Reactivity of Vinyl Epoxides/Oxetanes/Cyclopropanes toward Arynes: Access to Functionalized Phenanthrenes.

The reactivity of vinyl epoxides/oxetanes/cyclopropanes toward arynes has been demonstrated under mild conditions to give the corresponding phenanthrenes in moderate to good yields. This transition-metal-free cascade process involves a series of Diels-Alder reaction, ring-opening aromatization, and ene reaction. Various functionalized phenanthrenes could be synthesized utilizing the versatile hydroxy group. Interestingly, vinyl epoxides/oxiranes experience preferentially the Diels-Alder reaction toward arynes over nucleophilic attack of epoxides/oxiranes.

Introduction

As highly electrophilic reactive intermediates, arynes have recently gained great attention in organic synthesis.[1] Because of the high strain and low-lying lowest unoccupied molecular orbital (LUMO), arynes could experience nucleophilic attack readily by various neutral nucleophiles to generate versatile zwitterions. Owing to the strong nucleophilicity of aziridines and thioethers, arynes triggered ring-opening functionalization of aziridines,[2] and cyclic thioethers[3] have been developed well. However, the reactions of arynes and weakly nucleophilic strained rings (such as epoxides,[4] oxetanes, and cyclopropanes) are less developed.

Vinyl strained rings are versatile synthetic building blocks due to the presence of a vinyl moiety and the highly strained ring.[5] Therefore, the reactivity of vinyl strained rings toward arynes has two possible pathways. Strained rings could nucleophilic attack arynes to generate the highly reactive zwitterions, followed by intramolecular annulation. Alternatively, the aryne Diels–Alder reaction[6] could trigger ring-opening of strained rings. In 2012, Saito and co-workers disclosed an elegant [6 + 2] cycloaddition reaction of vinyl azetidines and arynes to access 1-benzazocines (Scheme a).[7] Recently, Studer and Yudin further developed a sophisticated [5 + 2] cycloaddition reaction of vinyl aziridines and arynes that resulted in benzazepines (Scheme b).[8] In sharp contrast to vinyl azetidines/aziridines, we envisioned that ring-opening of vinyl epoxides/oxetanes/cyclopropanes is triggered by the aryne Diels–Alder reaction (Scheme c).

Scheme 1

Reactivity of Vinyl Strained Rings toward Arynes

The phenanthrene unit constitutes a key structural motif in several pharmaceutically relevant compounds, therefore the development of efficient and practical approaches for the synthesis of phenanthrene derivatives has gained immense attention.[9] Despite the fact that palladium-catalyzed aryne annulation approaches to phenanthrenes have been developed well,[10] metal-free synthesis of phenanthrenes from arynes has been rarely studied. Recently, Wu[11] and Tiwari[12] developed elegant metal-free synthesis of phenanthrenes from α, β-unsaturated compounds and β-bromovinylarenes with arynes, respectively. Despite the success of these synthetic approaches, the development of transition-metal-free methodology for the synthesis of phenanthrenes without versatile functional groups is still highly desirable. In continuation of our work in the developing ring-opening functionalization of vinyl strained rings and aryne chemistry,[13] we are interested in preparing phenanthrenes having hydroxy groups from arynes under transition-metal-free conditions. Significantly, various functionalized phenanthrenes would be synthesized utilizing the versatile hydroxy group.

Results and Discussion

We began our studies with aryne precursor 1a and 2-(1-phenylvinyl)oxirane 2a as the benchmark substrates under various conditions (Table ). To our delight, the desired product 3aa was obtained in a 56% yield using CsF as a fluorine source in acetonitrile at room temperature (Table , entry 1). The yield of 3aa increased to 68% along with O-Ph byproduct 3aa′ in a 15% yield when the temperature of the reaction increased to 50 °C (Table , entry 2). However, the yield of 3aa declined slightly when running the reaction at 80 °C (Table , entry 3). The reaction was conducted in tetrahydrofuran (THF) at 70 °C, resulting in a 28% yield (Table , entry 4). The desired 3aa was obtained in a 41% yield using KF as a fluoride source in MeCN at 100 °C (Table , entry 5). Only a 20% yield of 3aa was obtained using tetrabutylammonium fluoride (TBAF) as a fluoride source in THF at room temperature (Table , entry 6). The desired 3aa was obtained in a 50% yield using KF/18-C-6 as a fluoride source in MeCN at room temperature (Table , entry 7). It was found that the reaction also proceeded smoothly in 1,4-dioxane, giving the desired 3aa in a 55% yield (Table , entry 8), although increasing the temperature to 50 °C did not improve the yield (Table , entry 9). Unfortunately, increasing the aryne precursors and fluoride sources also cannot improve the yield (Table , entry 10).

Table 1

Reaction Optimizationa

entry	fluoride (equiv)	solvent	temp (°C)	yield (%)
1	CsF	MeCN	rt	56
2	CsF	MeCN	50	68
3	CsF	MeCN	80	61
4	CsF	THF	70	28
5	KF	MeCN	100	41
6	TBAF	THF	rt	20
7	KF/18-C-6	MeCN	rt	50
8	KF/18-C-6	1,4-dioxane	rt	55
9	KF/18-C-6	1,4-dioxane	50	50
10b	CsF	MeCN	50	68

Reaction conditions: 1a (0.2 mmol), 2a (0.48 mmol), fluoride source (0.8 mmol), solvent (2 mL), and 6 h; isolated yields after column chromatography.

2a (0.6 mmol) and fluoride source (1 mmol).

Having the optimal conditions in hand, the scope of the aryne precursors and vinyl epoxides/oxetanes was investigated (Scheme ). Different arynes were tested first (3ba–da). The symmetrically disubstituted (OMe and Me) aryne precursors reacted smoothly with 2-(1-phenylvinyl)oxirane 2a, resulting in the desired products 3ba and 3ca in 65 and 71% yields, respectively. In addition, the unsymmetrical (3-OMe) benzyne precursor 1d reacted with 2a, affording a mixture of regioisomers (>10:1 ratio) in a 45% combined yield.[14] Subsequently, the scope of vinyl epoxides was screened. To our delight, representative aryl vinyl epoxides with electron-donating (Me, OMe, and Ph) or electron-withdrawing (F, Cl, and Br) groups in the benzene ring all worked well, giving the desired products (3ab–ag) in 51–67% yields. The symmetrically trisubstituted phenyl vinyl epoxide 2h afforded the desired product 3ah in a 55% yield. It is worth noting that the unsymmetrical phenyl vinyl epoxide 2i gave regioisomeric (1.5:1 ratio) product 3ai in a 53% yield. Vinyl methyl-substituted epoxide 2j gave two isolated diastereoisomers 3aj and 3aj′ in 24 and 22% yields, respectively. The structure of 3aj was confirmed unambiguously by single-crystal X-ray diffraction (XRD, CCDC 2113705). Additionally, vinyl phenyl-substituted epoxide 2k gave the diastereoisomer 3ak (dr = 1.5:1) in a 68% yield. Delightedly, the thienyl-substituted vinyl epoxide 2l also worked well in this reaction, affording the desired product 3al in a 61% yield. However, (E)-2-styryloxirane 2m gave [3 + 1] cycloaddition product 3am in a 50% yield. Encouraged by the abovementioned results, we turned to examine vinyl oxetanes. As expected, vinyl oxetanes with electron-donating (Me and Ph) or electron-withdrawing (F and Br) groups or trisubstituted groups in the aromatic ring worked well, giving the desired products (3an–ar) in moderate yields. Compared with vinyl epoxides/oxetanes, 2-(1-phenylvinyl)tetrahydrofuran 2t only gave the desired product 3at in a 16% yield.

Scheme 2

Scope of Arynes and Vinyl Epoxides/Oxetanes

Reaction conditions: 1 (0.2 mmol), 2 (0.48 mmol), CsF (0.8 mmol), MeCN (2 mL), 50 °C, and 6 h; isolated yields.

To further understand the ring-opening reaction, we conducted some essential control experiments. The vinyl donor–acceptor cyclopropane 4a could react smoothly with 1a under the standard conditions resulted in the desired ring-opening product 5aa in an 80% yield (Scheme a). In sharp contrast, vinyl cyclopropane 4b afforded the products 5ab1, 5ab2, and 5ab3 in 48, 17, and 30% yields, respectively (Scheme b). These two results indicated that the ring strain of cyclopropane and polarity of the C–C bond is indispensable in this ring-opening reaction. Unfortunately, the reaction of 1a and vinyl thiirane 4c was very messy even at room temperature (Scheme c).[3] Due to the strong nucleophilicity of thiirane, the sulfonium yield formation might contend with the Diels–Alder reaction. Similar to vinyl thiirane, vinyl aziridine 4d also gave a very messy reaction by the same token (Scheme d).[2] It is worth noting that no valuable product was detected by GC–MS in the reaction of vinyl oxirane 4e and 1a (Scheme e). The result indicated that the aryl group was necessary for the Diels–Alder reaction. Different from thiirane and aziridine, epoxide 4e displayed low reactivity toward arynes. Only an 18% yield of 5af was detected by the crude 1H NMR,[4] and the conversion of epoxide 4f was less than 30% (Scheme f). Based on the abovementioned experimental results, the reactivity toward arynes is aziridines/thioethers > styrenes > epoxides/oxetanes > cyclopropanes.

Scheme 3

Control Experiments

To prove the practicality of this approach, we executed the large-scale synthesis and further synthetic application for functionalized phenanthrenes (Scheme ). When the reaction was scaled up to 5 mmol, 776 mg of 3aa was obtained in a 52% yield. Then, a series of transformations of 3aa were conducted utilizing the versatile hydroxy group. Surprisingly, 3aa would transform into benzoyl phenanthrene 6 in an 85% yield in the presence of Cs2CO3 in dimethyl sulfoxide (DMSO) at 150 °C. As a ubiquitous nucleophile, a hydroxy group could react with various electrophiles to the corresponding functionalized phenanthrenes. For example, 3aa reacted with propargyl bromide with the assistance of NaH in THF at 45 °C, affording the product 7 in an 88% yield. In addition, 3aa was easily protected by benzoyl chloride (BzCl) and 4-methylbenzenesulfonyl chloride (TsCl) to yield the corresponding 8 and 9 in 93 and 85% yields, respectively. In addition, 9 would further transform using the OTs as a good leaving group. With the help of NaH, 9 could generate the styryl phenanthrene 10 in a 90% yield in THF at 60 °C. In addition, typical nucleophiles (BnNH2 and NaN3) could react with 9 to give the corresponding functionalized phenanthrenes 11 and 12 in 62 and 78% yields, respectively.

Scheme 4

Larger Synthesis and Synthetic Application for Functionalized Phenanthrenes

Based on the abovementioned experimental results, a plausible reaction mechanism is proposed in Scheme . Initially, aryl vinyl epoxides/cyclopropanes 2 reacted with in situ-generated arynes to yield the key intermediate A via the Diels–Alder reaction. Owing to the ring strain and polarity of the C–O/C–C bond (X = O or C(CO2Me)2), A readily experience ring-opening romanization, resulting in the corresponding intermediate B, which would further react with arynes to the final product 3 through the ene reaction. In the case of vinyl cyclopropane (X = CH2), A not only could react with aryne to generate 5ab1 through the ene reaction but also generate the corresponding 5ab2 and 5ab3 through 1,3-hydrogen transfer and oxidative aromatization, respectively.

Scheme 5

Plausible Mechanism

Conclusions

In summary, we have developed a transition-metal-free procedure for the synthesis of phenanthrene from vinyl epoxides/oxetanes/cyclopropanes with arynes under mild conditions. This unique cascade reaction appeared to combine the Diels–Alder reaction, ring-opening romanization, and ene reaction. In addition, various functionalized phenanthrenes could be synthesized utilizing the versatile hydroxy group. Interestingly, vinyl epoxides/oxiranes experience preferentially the Diels–Alder reaction toward arynes over nucleophilic attack of epoxides/oxiranes. Further efforts are ongoing in our laboratory to explore other ring-opening functionalization of vinyl strained rings.

Experimental Section

General Information

All reagents purchased from commercial sources were used as received. The silica gel for column chromatography was supplied as 300–400 meshes. The 1H and 13C NMR spectra are referenced to the residual solvent signals (7.26 ppm for 1H and 77.0 ppm for 13C in CDCl3). The high-resolution mass spectrometry (HRMS) spectra were recorded on a Bruker MicroTOF Q II spectrometer. Vinyl cyclopropane 4a(15) and 4b,[13a] vinyl thiirane 4c,[16] and vinyl aziridine 4d(17) were synthesized according to the literature.

General Procedures for the Synthesis of Vinyl Epoxides 2a–l and Vinyl Tetrahydrofuran 2t

To a 100 mL flame-dried round flask with a stir bar, methyltriphenylphosphonium bromide (2.32 g, 6.5 mmol) and dry THF (30 mL) were added. The reaction solution was protected by argon, and cooled to −78 °C, and n-BuLi (2.6 mL, 6.5 mmol) was added slowly in 30 min. Then, acyl epoxides (5.0 mmol) in THF (5 mL) were added slowly, and the reaction was monitored by thin layer chromatography (TLC). The reaction mixture was quenched with saturated NH4Cl and the mixture was extracted with CH2Cl2. The organic layers were dried over MgSO4 and filtered. The solvent was evaporated in vacuo and the residue was purified by column chromatography (50:1 PE/EA) to afford the corresponding vinyl epoxides.

2-(1-Phenylvinyl)oxirane (2a)[13a]

Slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.48–7.44 (m, 2 H), 7.39–7.31(m, 3 H), 5.45 (d, J = 0.8 Hz, 1 H), 5.38 (s, 1 H), 3.70–3.67 (m, 1 H), 3.05 (dd, J = 5.9, 4.1 Hz, 1 H), 2.64 (dd, J = 6.0, 2.6 Hz, 1 H); 13C NMR (100 MHz, CDCl3) δ 144.6, 137.9, 128.4, 128.0, 126.2, 112.6, 52.3, 49.5.

2-(1-(p-Tolyl)vinyl)oxirane (2b)[18]

Slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.36 (d, J = 8.1 Hz, 2 H), 7.18 (d, J = 8.0 Hz, 2 H), 5.42 (s, 1 H), 5.34 (s, 1 H), 3.68 (t, J = 3.0 Hz, 1 H), 3.04 (dd, J = 5.9, 4.1 Hz, 1 H), 2.63 (dd, J = 6.0, 2.6 Hz, 1 H), 2.37 (s, 3 H). 13C NMR (100 MHz, CDCl3) δ 144.4, 137.9, 135.1, 129.1, 126.0, 111.7, 52.4, 49.5, 21.1.

2-(1-(4-Methoxyphenyl)vinyl)oxirane (2c)

Slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.44–7.36 (m, 2 H), 6.93–6.85 (m, 2 H), 5.37 (s, 1 H), 5.29 (s, 1 H), 3.82 (s, 3 H), 3.66 (t, J = 3.2 Hz, 1 H), 3.04 (dd, J = 5.9, 4.1 Hz, 1 H), 2.63 (dd, J = 6.0, 2.6 Hz, 1 H). 13C NMR (100 MHz, CDCl3) δ 159.6, 144.0, 130.5, 127.3, 113.8, 110.9, 55.2, 52.4, 49.3. HRMS (ESI) m/z: [M + Na]+ calcd for 199.0730 C11H12O2Na, found 199.0732.

2-(1-([1,1′-Biphenyl]-4-yl)vinyl)oxirane (2d)

White solid. mp 90.4–92.7 °C. 1H NMR (400 MHz, CDCl3) δ 7.60 (dd, J = 8.2, 2.1 Hz, 4 H), 7.55 (d, J = 8.4 Hz, 2 H), 7.45 (t, J = 7.6 Hz, 2 H), 7.37 (d, J = 7.4 Hz, 1 H), 5.51 (s, 1 H), 5.41 (s, 1 H), 3.73 (t, J = 3.1 Hz, 1 H), 3.08 (dd, J = 5.9, 4.1 Hz, 1 H), 2.68 (dd, J = 5.9, 2.6 Hz, 1 H). 13C NMR (100 MHz, CDCl3) δ 144.1, 140.9, 140.6, 136.8, 128.8, 127.4, 127.2, 127.0, 126.6, 112.6, 52.3, 49.5. HRMS (ESI) m/z: [M + H]+ calcd for 223.1117 C16H15O, found 223.1108.

2-(1-(4-Fluorophenyl)vinyl)oxirane (2e)

Slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.47–7.38 (m, 2 H), 7.09–7.00 (m, 2 H), 5.40 (s, 1 H), 5.37 (s, 1 H), 3.64 (t, J = 3.2 Hz, 1 H), 3.03 (dd, J = 5.8, 4.1 Hz, 1 H), 2.61 (dd, J = 5.9, 2.6 Hz, 1 H). 13C NMR (100 MHz, CDCl3) δ 162.6 (d, 1JC–F = 247.2 Hz), 143.6, 133.9 (d, 4JC–F = 3.4 Hz), 127.9 (d, 3JC–F = 8.0 Hz), 115.2 (d, 2JC–F = 21.5 Hz), 112.9 (d, 5JC–F = 1.2 Hz), 52.3, 49.1. 19F NMR (376 MHz, CDCl3) δ −114.06. GC–MS (EI) m/z: 164.1, 149.0, 135.1, 133.1, 109.1.

2-(1-(4-Chlorophenyl)vinyl)oxirane (2f)

Slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.38 (d, J = 8.6 Hz, 2 H), 7.32 (d, J = 8.6 Hz, 2 H), 5.44 (s, 1 H), 5.40 (s, 1 H), 3.64 (t, J = 3.2 Hz, 1 H), 3.04 (dd, J = 5.8, 4.1 Hz, 1 H), 2.61 (dd, J = 5.9, 2.6 Hz, 1 H). 13C NMR (100 MHz, CDCl3) δ 143.6, 136.3, 134.0, 128.6, 127.6, 113.5, 52.2, 49.2. GC–MS (EI) m/z: 180.0, 165.0, 151.0, 145.1, 125.1, 115.1.

2-(1-(4-Bromophenyl)vinyl)oxirane (2g)

Slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.51–7.45 (m, 2 H), 7.35–7.29 (m, 2 H), 5.44 (s, 1 H), 5.40 (s, 1 H), 3.64 (t, J = 3.1 Hz, 1 H), 3.03 (dd, J = 5.8, 4.1 Hz, 1 H), 2.61 (dd, J = 5.9, 2.6 Hz, 1 H). 13C NMR (100 MHz, CDCl3) δ 143.6, 136.3, 133.9, 128.6, 127.6, 113.5, 52.2, 49.2. GC–MS (EI) m/z: 223.9, 194.9, 168.9, 145.1, 125.1, 115.1.

2-(1-(4-Bromo-3,5-dimethylphenyl)vinyl)oxirane (2h)

Slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.15 (s, 2 H), 5.42 (s, 1 H), 5.37 (s, 1 H), 3.64 (t, J = 3.2 Hz, 1 H), 3.04 (dd, J = 5.8, 4.1 Hz, 1 H), 2.62 (dd, J = 5.9, 2.6 Hz, 1 H), 2.43 (s, 6 H). 13C NMR (100 MHz, CDCl3) δ 143.9, 138.3, 136.4, 127.3, 126.0, 113.0, 52.2, 49.4, 23.9. HRMS (ESI) m/z: [M + Na]+ calcd for 275.0042 C12H13OBrNa, found 275.0041.

2-(1-(3,4-Dimethylphenyl)vinyl)oxirane (2i)

Slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.25 (s, 1 H), 7.21 (d, J = 7.8 Hz, 1 H), 7.13 (d, J = 7.8 Hz, 1 H), 5.41 (d, J = 0.6 Hz, 1 H), 5.32 (s, 1 H), 3.68 (t, J = 3.1 Hz, 1 H), 3.05 (dd, J = 6.0, 4.1 Hz, 1 H), 2.64 (dd, J = 6.0, 2.6 Hz, 1 H), 2.30 (s, 3 H), 2.28 (s, 3 H). 13C NMR (100 MHz, CDCl3) δ 144.5, 136.6, 135.6, 129.7, 127.3, 123.5, 111.5, 52.4, 49.6, 19.8, 19.4. HRMS (ESI) m/z: [M + Na]+ calcd for 197.0937 C12H14ONa, found 197.0935.

2-Methyl-3-(1-(p-tolyl)vinyl)oxirane (2j)

Slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.34 (d, J = 8.0 Hz, 2 H), 7.18 (d, J = 8.0 Hz, 2 H), 5.39 (s, 1 H), 5.31 (d, J = 9.7 Hz, 1 H), 3.39 (s, 1 H), 2.90–2.85 (m, 1 H), 2.37 (s, 3 H), 1.46 (d, J = 5.2 Hz, 3 H). 13C NMR (100 MHz, CDCl3) δ 144.3, 137.8, 135.3, 129.1, 125.9, 111.1, 59.4, 57.6, 21.1, 17.7. GC–MS (EI) m/z: 174.1, 159.1, 145.1, 131.1, 128.1, 115.1.

2-Phenyl-3-(1-phenylvinyl)oxirane (2k)

White solid. mp 36.5–37.7 °C. 1H NMR (400 MHz, CDCl3) δ 7.55–7.30 (m, 10 H), 5.58 (d, J = 0.5 Hz, 1 H), 5.54 (s, 1 H), 3.78 (s, 1 H), 3.75 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 144.0, 137.7, 137.0, 128.6, 128.5, 128.3, 128.1, 126.0, 125.6, 112.0, 62.5, 61.5. HRMS (ESI) m/z: [M + Na]+ calcd for 245.0937 C16H14ONa, found 245.0929.

2-(1-(Thiophen-2-yl)vinyl)oxirane (2l)

Slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.23 (d, J = 5.1 Hz, 1 H), 7.16 (d, J = 3.5 Hz, 1 H), 7.02 (dd, J = 4.9, 3.8 Hz, 1 H), 5.48 (s, 1 H), 5.29 (s, 1 H), 3.80–3.66 (m, 1 H), 3.02 (dd, J = 5.8, 4.1 Hz, 1 H), 2.69 (dd, J = 5.9, 2.6 Hz, 1 H). 13C NMR (100 MHz, CDCl3) δ 140.9, 138.3, 127.3, 124.8, 123.9, 111.2, 51.9, 48.9. GC–MS (EI) m/z: 152.1, 135.1, 123.1, 109.0, 97.0.

2-(1-Phenylvinyl)tetrahydrofuran (2t)[20]

Slightly yellow oil. 1H NMR (300 MHz, CDCl3) δ 7.45–7.27 (m, 5 H), 5.37 (t, J = 1.4 Hz, 1 H), 5.30 (s, 1 H), 4.86 (t, J = 6.9 Hz, 1 H), 4.07–3.97 (m, 1 H), 3.97–3.82 (m, 1 H), 2.18–2.03 (m, 1 H), 1.99–1.85 (m, 2 H), 1.73–1.55 (m, 1 H). 13C NMR (75 MHz, CDCl3) δ 149.6, 139.9, 128.2, 127.4, 126.7, 111.6, 80.1, 68.4, 31.7, 25.5.

General Procedures for the Synthesis of Vinyl Epoxide 2m

To a 100 mL flame-dried round flask with a stir bar, NaH (60% purity, 44 mg, 1.1 mmol) and dry THF (2 mL) were added, followed by NaI (14 mg, 10 mol %). The reaction solution was cooled to 0 °C, then (E)-1-chloro-3-phenylprop-2-en-1-ol (182 mg, 1 mmol) in THF (1 mL) was added slowly over 30 min to the abovementioned solution. The reaction was monitored by TLC. Then, the reaction mixture was quenched with saturated NH4Cl and the mixture was extracted with EtOAc. The organic layers were dried over MgSO4 and filtered. The solvent was evaporated in vacuo and the residue was purified by column chromatography (50:1 PE/EA) to afford the desired (E)-2-styryloxirane (2m)[19] as a slightly yellow oil: 1H NMR (300 MHz, CDCl3) δ 7.43–7.26 (m, 5 H), 6.82 (d, J = 16.0 Hz, 1 H), 5.88 (dd, J = 16.0, 8.0 Hz, 1 H), 3.60–3.47 (m, 1 H), 3.11–3.02 (m, 1 H), 2.78 (dd, J = 5.2, 2.6 Hz, 1 H). 13C NMR (75 MHz, CDCl3) δ 136.0, 134.5, 128.6, 128.0, 126.9, 126.4, 52.6, 49.2.

General Procedures for the Synthesis of Vinyl Oxetanes 2n–t[21]

To a 25 mL screw-capped test tube with a stir bar, vinyl epoxides (1 mmol), t-BuOH (5 mL), and trimethylsulfoxonium iodide (440 mg, 2 mmol) were added. Then, t-BuOK (224 mg, 2 mmol) was added to the abovementioned solution. The mixture was stirred at 50 °C for 12 h. Most of the reaction mixture was evaporated, and the residue was purified by column chromatography (50:1 PE/EA) to afford the corresponding vinyl oxetanes.

2-(1-Phenylvinyl)oxetane (2n)[20]

Slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.41–7.27 (m, 5 H), 5.70 (t, J = 7.5 Hz, 1 H), 5.60 (s, 1 H), 5.57 (s, 1 H), 4.82–4.76 (m, 1 H), 4.60–4.55 (m, 1 H), 2.98–2.90 (m, 1 H), 2.55–2.46 (m, 1 H). 13C NMR (100 MHz, CDCl3) δ 148.8, 137.5, 128.4, 127.8, 125.9, 110.9, 81.8, 68.0, 29.0.

2-(1-(p-Tolyl)vinyl)oxetane (2o)

Slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.24 (d, J = 8.1 Hz, 2 H), 7.15 (d, J = 8.1 Hz, 2 H), 5.68 (t, J = 7.5 Hz, 1 H), 5.53 (s, 1 H), 5.52 (s, 1 H), 4.84–4.74 (m, 1 H), 4.59–4.54 (m, 1 H), 3.00–2.87 (m, 1 H), 2.52–2.44 (m, 1 H), 2.35 (s, 3 H). 13C NMR (100 MHz, CDCl3) δ 148.6, 137.5, 134.5, 129.1, 125.7, 109.9, 81.8, 68.0, 29.0, 21.0. HRMS (ESI) m/z: [M + Na]+ calcd for 197.0937 C12H14ONa, found 197.0937.

2-(1-([1,1′-Biphenyl]-4-yl)vinyl)oxetane (2p)

White solid. mp 89.8–92.4 °C. 1H NMR (400 MHz, CDCl3) δ 7.67–7.57 (m, 4 H), 7.52–7.43 (m, 4 H), 7.38 (t, J = 7.3 Hz, 1 H), 5.77 (t, J = 7.5 Hz, 1 H), 5.65 (s, 2 H), 4.71–4.66 (m, 1 H), 4.68–4.55 (m, 1 H), 3.10–2.80 (m, 1 H), 2.66–2.46 (m, 1 H). 13C NMR (100 MHz, CDCl3) δ 148.4, 140.6, 140.5, 136.4, 128.7, 127.3, 127.1, 126.9, 126.2, 110.8, 81.7, 68.1, 29.0. HRMS (ESI) m/z: [M + Na]+ calcd for 259.1093 C17H16ONa, found 259.1090.

2-(1-(4-Fluorophenyl)vinyl)oxetane (2q)

Slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.39–7.28 (m, 2 H), 7.08–6.98 (m, 2 H), 5.64 (t, J = 7.5 Hz, 1 H), 5.54 (s, 1 H), 5.48 (s, 1 H), 4.83–4.72 (m, 1 H), 4.59–4.49 (m, 1 H), 3.01–2.82 (m, 1 H), 2.60–2.38 (m, 1 H). 13C NMR (100 MHz, CDCl3) δ 162.5 (d, 1JC–F = 246.9 Hz), 147.9, 133.7 (d, 4JC–F = 3.4 Hz), 127.7 (d, 3JC–F = 7.9 Hz), 115.3 (d, 2JC–F = 21.3 Hz), 111.1, 81.8, 68.0, 28.8. 19F NMR (376 MHz, CDCl3) δ −114.42. GC–MS (EI) m/z: 178.1, 150.1, 133.1, 121.1, 101.1.

2-(1-(4-Bromophenyl)vinyl)oxetane (2r)

White solid. mp 46.7–48.9 °C. 1H NMR (400 MHz, CDCl3) δ 7.45 (d, J = 8.5 Hz, 2 H), 7.21 (d, J = 8.5 Hz, 2 H), 5.63 (t, J = 7.5 Hz, 1 H), 5.57 (s, 1 H), 5.53 (s, 1 H), 4.79–4.74 (m, 1 H), 4.60–4.48 (m, 1 H), 2.99–2.84 (m, 1 H), 2.55–2.39 (m, 1 H). 13C NMR (100 MHz, CDCl3) δ 147.9, 136.5, 131.5, 127.6, 121.8, 111.7, 81.6, 68.0, 28.7. HRMS (ESI) m/z: [M + Na]+ calcd for 260.9885 C11H11OBrNa, found 260.9884.

2-(1-(4-Bromo-3,5-dimethylphenyl)vinyl)oxetane (2s)

Slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.05 (s, 2 H), 5.64 (t, J = 7.4 Hz, 1 H), 5.54 (s, 1 H), 5.50 (s, 1 H), 4.79–4.74 (m, 1 H), 4.57–4.52 (m, 1 H), 2.97–2.84 (m, 1 H), 2.54–2.35 (m, 7 H). 13C NMR (100 MHz, CDCl3) δ 148.3, 138.3, 136.2, 127.0, 125.8, 111.3, 81.7, 68.0, 28.8, 24.0. HRMS (ESI) m/z: [M + Na]+ calcd for 289.0198 C13H15OBrNa, found 289.0196.

General Procedures for the Synthesis of Phenanthrenes 3aa–da, 3ab–at, 5aa, 5ab1, 5ab2, and 5ab3

To a 10 mL flame-dried screw-capped test tube with a stir bar, aryne precursor 1 (0.48 mmol, 2.4 equiv), vinyl epoxides/oxetanes 2 (0.2 mmol), and MeCN (2 mL) were added. Then, CsF (70 mg, 1.2 mmol, 4 equiv) was added to the abovementioned solution. The mixture was stirred at 50 °C for 6 h. Most of the reaction mixture was evaporated, and the residue was purified by column chromatography (10:1 PE/EA) to afford the desired phenanthrenes 3.

2-(Phenanthren-9-yl)-2-phenylethan-1-ol (3aa)

Overall, 41 mg of 3aa was obtained from 1a (143 mg, 0.48 mmol) and 2a (29 mg, 0.2 mmol) in a 68% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 106.9–107.8 °C. 1H NMR (400 MHz, CDCl3) δ 8.73 (d, J = 8.2 Hz, 1 H), 8.68 (d, J = 7.9 Hz, 1 H), 8.09 (d, J = 8.2 Hz, 1 H), 7.92 (d, J = 7.4 Hz, 1 H), 7.80 (s, 1 H), 7.71–7.57 (m, 3 H), 7.54 (t, J = 7.5 Hz, 1 H), 7.37 (d, J = 7.4 Hz, 2 H), 7.31 (t, J = 7.3 Hz, 2 H), 7.23 (t, J = 7.1 Hz, 1 H), 4.99 (t, J = 6.6 Hz, 1 H), 4.50–4.40 (m, 1 H), 4.39–4.28 (m, 1 H), 1.74 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 141.2, 134.8, 131.3, 131.1, 131.0, 129.8, 129.4, 128.7, 128.6, 128.44, 128.39, 126.9, 126.73, 126.69, 126.6, 126.3, 125.3, 124.5, 123.2, 122.4, 66.1, 49.3. HRMS (ESI) m/z: [M + Na]+ calcd for 321.1250 C22H18ONa, found 321.1244.

9-(2-Phenoxy-1-phenylethyl)phenanthrene (3aa′)

Overall, 11 mg of 3aa′ was obtained from 1a (143 mg, 0.48 mmol) and 2a (29 mg, 0.2 mmol) in a 15% yield; purified by column chromatography (100:1 PE/EA); white solid. mp 50.4–52.8 °C 1H NMR (500 MHz, CDCl3) δ 8.75 (d, J = 8.1 Hz, 1 H), 8.69 (d, J = 8.2 Hz, 1 H), 8.11 (d, J = 8.2 Hz, 1 H), 7.87 (d, J = 7.8 Hz, 1 H), 7.73 (s, 1 H), 7.68–7.57 (m, 3 H), 7.57–7.51 (m, 1 H), 7.39 (d, J = 7.3 Hz, 2 H), 7.33–7.27 (m, 4 H), 7.23 (t, J = 7.3 Hz, 1 H), 7.00–6.92 (m, 3 H), 5.30 (t, J = 7.0 Hz, 1 H), 4.75 (dd, J = 9.6, 7.1 Hz. 1 H), 4.63 (dd, J = 9.6, 6.9 Hz, 1 H). 13C NMR (75 MHz, CDCl3) δ 158.7, 141.4, 134.8, 131.4, 131.04, 130.96, 129.9, 129.5, 128.8, 128.59, 128.55, 126.8, 126.71, 126.68, 126.5, 126.2, 126.0, 124.5, 123.2, 122.4, 120.9, 114.8, 70.7, 46.5. HRMS (ESI) m/z: [M + Na]+ calcd for 397.1563 C28H22ONa, found 397.1562.

2-(2,3-Dimethoxyphenanthren-9-yl)-2-(3,4-dimethoxyphenyl)ethan-1-ol (3ba)

Overall, 54 mg of 3ba was obtained from 1b (172 mg, 0.48 mmol) and 2a (29 mg, 0.2 mmol) in a 65% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 203.1–204.7 °C. 1H NMR (400 MHz, CDCl3) δ 8.59 (d, J = 8.3 Hz, 1 H), 8.10 (d, J = 8.3 Hz, 1 H), 8.00 (s, 1 H), 7.68 (s, 1 H), 7.61 (t, J = 7.5 Hz, 1 H), 7.51 (t, J = 7.5 Hz, 1 H), 7.27 (s, 1 H), 6.91 (d, J = 9.5 Hz, 2 H), 6.82 (d, J = 8.0 Hz, 1 H), 4.94 (t, J = 6.4 Hz, 1 H), 4.47–4.36 (m, 1 H), 4.36–4.26 (m, 1 H), 4.13 (s, 3 H), 4.06 (s, 3 H), 3.85 (s, 3 H), 3.81 (s, 3 H), 1.89 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 149.4, 149.3, 149.1, 147.8, 133.8, 133.2, 130.4, 130.3, 126.4, 125.9, 125.6, 124.5, 124.4, 124.3, 122.6, 120.4, 111.8, 111.2, 108.4, 103.0, 66.1, 56.0, 55.9, 55.8, 55.7, 48.7. HRMS (ESI) m/z: [M + Na]+ calcd for 441.1672 C26H26O5Na, found 441.1668.

2-(2,3-Dimethylphenanthren-9-yl)-2-(3,4-dimethylphenyl)ethan-1-ol (3ca)

White solid. Overall, 50 mg of 3ca was obtained from 1c (157 mg, 0.48 mmol) and 2a (29 mg, 0.2 mmol) in a 71% yield; purified by column chromatography (10:1 PE/EA); mp 132.7–134.3 °C. 1H NMR (400 MHz, CDCl3) δ 8.70 (d, J = 8.2 Hz, 1 H), 8.43 (s, 1 H), 8.09 (d, J = 8.2 Hz, 1 H), 7.71 (d, J = 9.9 Hz, 2 H), 7.59 (t, J = 7.4 Hz, 1 H), 7.51 (t, J = 7.5 Hz, 1 H), 7.16–7.02 (m, 3 H), 4.91 (t, J = 6.8 Hz, 1 H), 4.47–4.34 (m, 1 H), 4.35–4.23 (m, 1 H), 2.55 (s, 3 H), 2.50 (s, 3 H), 2.22 (s, 3 H), 2.20 (s, 3 H), 1.75 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 138.6, 136.9, 136.0, 135.8, 135.1, 134.0, 131.0, 130.8, 130.0, 129.6, 128.7, 128.2, 126.2, 126.0, 125.8, 124.6, 124.4, 122.9, 122.7, 66.3, 48.9, 20.6, 19.9, 19.8, 19.3. HRMS (ESI) m/z: [M + Na]+ calcd for 377.1876 C26H26O5Na, found 377.1876.

2-(4-Methoxyphenanthren-9-yl)-2-(3-methoxyphenyl)ethan-1-ol (3da)

White solid. Overall, 32 mg of 3da was obtained from 1d (157 mg, 0.48 mmol) and 2a (29 mg, 0.2 mmol) in a 45% yield; purified by column chromatography (10:1 PE/EA); mp 125.5–127.0 °C. 1H NMR (400 MHz, CDCl3) δ 9.76 (d, J = 8.4 Hz, 1 H), 8.09 (d, J = 8.1 Hz, 1 H), 7.76 (s, 1 H), 7.64–7.49 (m, 4 H), 7.22 (t, J = 7.9 Hz, 1 H), 7.19–7.12 (m, 1 H), 6.96 (d, J = 7.6 Hz, 1 H), 6.90 (s, 1 H), 6.76 (dd, J = 8.2, 2.3 Hz, 1 H), 4.95 (t, J = 6.7 Hz, 1 H), 4.32 (dd, J = 11.0, 6.7 Hz, 1 H), 4.22 (dd, J = 11.0, 6.7 Hz, 1 H), 4.13 (s, 3 H), 3.73 (s, 3 H), 1.77 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 159.9, 158.5, 142.9, 135.1, 133.8, 131.6, 131.2, 129.7, 129.0, 126.7, 126.00, 125.98, 125.8, 123.8, 121.7, 120.9, 120.3, 114.7, 111.8, 108.5, 66.2, 55.8, 55.1, 49.3. HRMS (ESI) m/z: [M + Na]+ calcd for 381.1461 C24H22O3Na, found 381.1452.

2-(6-Methylphenanthren-9-yl)-2-phenylethan-1-ol (3ab)

Overall, 42 mg of 3ab was obtained from 1a (143 mg, 0.48 mmol) and 2b (32 mg, 0.2 mmol) in a 67% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 142.3–144.4 °C. 1H NMR (400 MHz, CDCl3) δ 8.70 (d, J = 7.9 Hz, 1 H), 8.55 (s, 1 H), 8.00 (d, J = 8.5 Hz, 1 H), 7.93 (d, J = 7.3 Hz, 1 H), 7.75 (s, 1 H), 7.69–7.60 (m, 2 H), 7.40–7.36 (m, 3 H), 7.32 (t, J = 7.5 Hz, 2 H), 7.26–7.22 (d, J = 7.1 Hz, 1 H), 4.97 (t, J = 6.7 Hz, 1 H), 4.43 (dd, J = 11.1, 6.9 Hz, 1 H), 4.32 (dd, J = 11.1, 6.7 Hz, 1 H), 2.60 (s, 3 H), 1.96 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 141.3, 135.9, 134.7, 131.5, 131.1, 129.6, 129.0, 128.7, 128.6, 128.4, 128.4, 126.8, 126.6, 126.3, 124.3, 124.3, 122.9, 122.4, 66.1, 49.3, 21.8. HRMS (ESI) m/z: [M + Na]+ calcd for 335.1406 C23H20ONa, found 335.1404.

2-(6-Methoxyphenanthren-9-yl)-2-phenylethan-1-ol (3ac)

Overall, 38 mg of 3ac was obtained from 1a (143 mg, 0.48 mmol) and 2c (35 mg, 0.2 mmol) in a 58% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 45.7–46.5 °C. 1H NMR (400 MHz, CDCl3) δ 8.63–8.55 (m, 1 H), 8.09 (d, J = 2.4 Hz, 1 H), 7.99 (d, J = 9.1 Hz, 1 H), 7.89 (dd, J = 9.7, 7.4 Hz, 1 H), 7.67 (s, 1 H), 7.66–7.57 (m, 2 H), 7.35 (d, J = 7.3 Hz, 2 H), 7.30 (t, J = 7.5 Hz, 2 H), 7.22 (t, J = 7.1 Hz, 1 H), 7.17 (dd, J = 9.1, 2.5 Hz, 1 H), 4.94 (t, J = 6.8 Hz, 1 H), 4.43 (dd, J = 11.0, 7.0 Hz, 1 H), 4.31 (dd, J = 11.0, 6.7 Hz, 1 H), 3.98 (s, 3 H), 1.79 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 158.0, 141.2, 134.7, 132.6, 131.9, 129.4, 128.8, 128.7, 128.4, 126.9, 126.8, 126.2, 126.1, 125.7, 122.9, 122.5, 116.3, 104.7, 66.2, 55.4, 49.4. HRMS (ESI) m/z: [M + Na]+ calcd for 351.1356 C23H20O2Na, found 351.1353.

2-Phenyl-2-(6-phenylphenanthren-9-yl)ethan-1-ol (3ad)

Overall, 47 mg of 3ad was obtained from 1a (143 mg, 0.48 mmol) and 2d (44 mg, 0.2 mmol) in a 63% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 82.7–84.3 °C. 1H NMR (400 MHz, CDCl3) δ 8.83 (s, 1 H), 8.66 (d, J = 7.9 Hz, 1 H), 8.05 (d, J = 8.6 Hz, 1 H), 7.83 (d, J = 7.4 Hz, 1 H), 7.77–7.62 (m, 4 H), 7.62–7.48 (m, 2 H), 7.41 (t, J = 7.3 Hz, 2 H), 7.36–7.26 (m, 3 H), 7.22 (t, J = 7.3 Hz, 2 H), 7.13 (m, 1 H), 4.90 (t, J = 6.4 Hz, 1 H), 4.41–4.30 (m, 1 H), 4.30–4.16 (m, 1 H), 1.74 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 141.2, 141.1, 138.9, 134.70, 131.67, 131.3, 130.3, 123.0, 128.9, 128.8, 128.7, 128.5, 127. 5, 127.0, 126.9, 126.7, 126.0, 125.4, 125.0, 122.5, 121.5, 66.2, 49.4. HRMS (ESI) m/z: [M + Na]+ calcd for 397.1563 C28H20ONa, found 397.1559.

2-(6-Fluorophenanthren-9-yl)-2-phenylethan-1-ol (3ae)

New compound. Overall, 32 mg of 3ae was obtained from 1a (143 mg, 0.48 mmol) and 2e (33 mg, 0.2 mmol) in a 51% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 140.9–143.5 °C. 1H NMR (400 MHz, CDCl3) δ 8.58–8.47 (m, 1 H), 8.31 (dd, J = 11.0, 2.1 Hz, 1 H), 8.09–7.99 (m, 1 H), 7.96–7.87 (m, 1 H), 7.77 (s, 1 H), 7.70–7.61 (m, 2 H), 7.42–7.21 (m, 6 H), 4.92 (t, J = 6.6 Hz, 1 H), 4.49–4.37 (m, 1 H), 4.38–4.26 (m, 1 H), 1.74 (s, 1 H). 19F NMR (376 MHz, CDCl3) δ -114.17. 13C NMR (100 MHz, CDCl3) δ 161.2 (d, 1JC–F = 246.0 Hz), 141.0, 134.5, 132.9 (d, 3JC–F = 8.1 Hz), 131.8, 129.3, 129.2, 128.8, 128.7, 128.4, 127.8 (d, 4JC–F = 1.4 Hz), 127.4, 127.1, 126.8 (d, 3JC–F = 8.8 Hz), 126.7, 124.5 (d, 4JC–F = 2.1 Hz), 122.6, 115.5 (d, 2JC–F = 23.3 Hz), 108.2 (d, 2JC–F = 21.9 Hz), 66.1, 49.5. HRMS (ESI) m/z: [M + Na]+ calcd for 339.1156 C22H17OFNa, found 339.1160.

2-(6-Chlorophenanthren-9-yl)-2-phenylethan-1-ol (3af)

Overall, 41 mg of 3af was obtained from 1a (143 mg, 0.48 mmol) and 2f (36 mg, 0.2 mmol) in a 61% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 156.7–158.1 °C. 1H NMR (400 MHz, CDCl3) δ 8.60 (s, 1 H), 8.51 (d, J = 6.3 Hz, 1 H), 7.92 (d, J = 8.7 Hz, 1 H), 7.86 (d, J = 5.9 Hz, 1 H), 7.75 (s, 1 H), 7.60 (s, 2 H), 7.40 (d, J = 8.6 Hz, 1 H), 7.33–7.12 (m, 5 H), 4.85 (s, 1 H), 4.43–4.32 (m, 1 H), 4.32–4.21 (m, 1 H), 1.64 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 140.9, 134.5, 132.5, 132.3, 131.7, 129.5, 128.8, 128.7, 128.4, 127.4, 127.1, 126.9, 126.1, 125.5, 122.8, 122.5, 66.1, 49.4. HRMS (ESI) m/z: [M + Na]+ calcd for 335.0860 C22H17OClNa, found 335.0854.

2-(6-Bromophenanthren-9-yl)-2-phenylethan-1-ol (3ag)

Overall, 47 mg of 3ag was obtained from 1a (143 mg, 0.48 mmol) and 2g (45 mg, 0.2 mmol) in a 62% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 154.7–156.3 °C. 1H NMR (400 MHz, CDCl3) δ 8.73 (s, 1 H), 8.46 (d, J = 7.5 Hz, 1 H), 7.80 (d, J = 8.6 Hz, 2 H), 7.72 (s, 1 H), 7.61–7.51 (m, 2 H), 7.49 (d, J = 8.8 Hz, 1 H), 7.24–7.10 (m, 5 H), 4.79 (t, J = 6.5 Hz, 1 H), 4.39–4.27 (m, 1 H), 4.26–4.15 (m, 1 H), 1.65 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 140.9, 134.5, 132.5, 132.3, 131.7, 129.5, 128.8, 128.7, 128.4, 127.4, 127.1, 126.9, 126.1, 125.5, 122. 8, 122.5, 66.1, 49.4. HRMS (ESI) m/z: [M + Na]+ calcd for 339.0355 C22H17OBrNa, found 339.0341.

2-(6-Bromo-5,7-dimethylphenanthren-9-yl)-2-phenylethan-1-ol (3ah)

Overall, 44 mg of 3ah was obtained from 1a (143 mg, 0.48 mmol) and 2h (50 mg, 0.2 mmol) in a 55% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 146.3–147.7 °C. 1H NMR (400 MHz, CDCl3) δ 8.57–8.46 (m, 1 H), 7.93–7.85 (m, 1 H), 7.81 (s, 1 H), 7.73 (s, 1 H), 7.61–7.53 (m, 2 H), 7.37–7.28 (m, 4 H), 7.25–7.20 (m, 1 H), 4.90 (t, J = 6.7 Hz, 1 H), 4.45–4.36 (m, 1 H), 4.35–4.27 (m, 1 H), 3.12 (s, 3 H), 2.54 (s, 3 H), 1.66 (t, J = 5.8 Hz, 1 H). 13C NMR (100 MHz, CDCl3) δ 141.1, 135.9, 135.2, 134.1, 132.6, 131.3, 130.9, 130.2, 130.0, 128.9, 128.4, 128.3, 128.0, 127.0, 126.6, 125.9, 125.1, 123.3, 66.3, 49.3, 27.2, 25.1. HRMS (ESI) m/z: [M + Na]+ calcd for 427.0668 C24H21OBrNa, found 427.0662.

2-(6,7-Dimethylphenanthren-9-yl)-2-phenylethan-1-ol (3ai) and 2-(5,6-Dimethylphenanthren-9-yl)-2-phenylethan-1-ol (3ai′)

Overall, 35 mg of 3ai and 3ai′ was obtained from 1a (143 mg, 0.48 mmol) and 2i (35 mg, 0.2 mmol) in a 53% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 129.5–131.2 °C. Major isomer (3ai); 1H NMR (400 MHz, CDCl3) δ 8.65 (d, J = 8.1 Hz, 1 H), 8.48 (s, 1 H), 7.87 (d, J = 6.3 Hz, 2 H), 7.68 (s, 1 H), 7.64–7.55 (m, 2 H), 7.39 (d, J = 7.4 Hz, 2 H), 7.32 (t, J = 7.6 Hz, 2 H), 7.23 (t, J = 6.8 Hz, 1 H), 5.00 (t, J = 6.8 Hz, 1 H), 4.47–4.39 (m, 1 H), 4.32 (dd, J = 10.5, 6.9 Hz, 1 H), 2.50 (s, 3 H), 2.42 (s, 3 H), 1.76 (s, 1 H). Representative peaks of minor (3ai′); 1H NMR (400 MHz, CDCl3) δ 8.62 (d), 7.85–7.79 (m), 7.68 (s), 4.94 (t), 2.93 (s), 2.51 (s), 1.80 (s). Major isomer (3ai); 13C NMR (100 MHz, CDCl3) δ 141.30, 135.91, 135.59, 134.41, 131.12, 129.59, 129.35, 128.76, 128.54, 128.44, 126.85, 126.33, 126.18, 124.66, 124.37, 123.54, 122.21, 66.2, 49.2, 20.5, 20.3. Representative peaks of minor (3ai′); 141.4, 136.3, 134.6, 133.6, 130.8, 130.3, 129.4, 128.6, 128.3, 128.2, 125.9, 124.63, 124.61, 121.6, 66.3, 49.4, 22.1, 21.4. HRMS (ESI) m/z: [M + Na]+ calcd for 349.1563 C24H22ONa, found 348.1553.

(1R, 2S or 1S, 2R)-1-(6-Methylphenanthren-9-yl)-1-phenylpropan-2-ol (3aj)

Overall, 16 mg of 3aj was obtained from 1a (143 mg, 0.48 mmol) and 2j (35 mg, 0.2 mmol) in a 24% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 181.7–183.4 °C. 1H NMR (400 MHz, CDCl3) δ 8.65 (dd, J = 14.3, 7.4 Hz, 1 H), 8.50 (s, 1 H), 8.11 (d, J = 8.5 Hz, 1 H), 8.02 (s, 1 H), 7.95 (dd, J = 6.1, 2.9 Hz, 1 H), 7.67–7.58 (m, 2 H), 7.43–7.36 (m, 3 H), 7.23 (d, J = 7.7 Hz, 2 H), 7.15 (t, J = 7.3 Hz, 1 H), 4.84–4.74 (m, 1 H), 4.67 (d, J = 8.8 Hz, 1 H), 2.57 (s, 3 H), 2.19 (s, 1 H), 1.32 (d, J = 6.0 Hz, 3 H). 13C NMR (100 MHz, CDCl3) δ 141.5, 136.1, 135.2, 131.6, 131.3, 129.6, 129.5, 128.7, 128.52, 128.50, 128.4, 126.70, 126.66, 126.5, 124.3, 123.6, 123.0, 122.4, 70.0, 55.3, 21.8, 21.2. HRMS (ESI) m/z: [M + Na]+ calcd for 349.1563 C24H22ONa, found 349.1558.

(1R, 2R or 1S, 2S)-1-(6-Methylphenanthren-9-yl)-1-phenylpropan-2-ol (3aj)

Overall, 14 mg of 3aj′ was obtained from 1a (143 mg, 0.48 mmol) and 2j (35 mg, 0.2 mmol) in a 22% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 56.4–58.5 °C. 1H NMR (400 MHz, CDCl3) δ 8.68–8.61 (m, 1 H), 8.51 (s, 1 H), 8.08 (d, J = 8.5 Hz, 1 H), 7.92–7.88 (m, 1 H), 7.87 (s, 1 H), 7.65–7.56 (m, 2 H), 7.49 (d, J = 7.4 Hz, 2 H), 7.40 (d, J = 8.4 Hz, 1 H), 7.31 (t, J = 7.5 Hz, 2 H), 7.21 (t, J = 7.3 Hz, 1 H), 4.85–4.74 (m, 1 H), 4.64 (d, J = 7.3 Hz, 1 H), 2.58 (s, 3 H), 1.65 (s, 1 H), 1.38 (d, J = 6.1 Hz, 3 H). 13C NMR (100 MHz, CDCl3) δ 140.7, 136.7, 135.8, 131.7, 131.0, 129.4, 129.2, 129.0, 128.7, 128.6, 128.4, 127.0, 126.6, 126.2, 124.8, 124.2, 123.0, 122.4, 70.3, 54.2, 22.0, 21.8. HRMS (ESI) m/z: [M + Na]+ calcd for 349.1563 C24H22ONa, found 349.1564.

2-(Phenanthren-9-yl)-1,2-diphenylethan-1-ol (3ak)

Overall, 51 mg of 3ak (including two diastereoisomers) was obtained from 1a (143 mg, 0.48 mmol) and 2k (44 mg, 0.2 mmol) in a 68% yield; purified by column chromatography (10:1 PE/EA); white solid. Major isomer: 1H NMR (400 MHz, CDCl3) δ 8.67 (d, J = 8.1 Hz, 1 H), 8.65–8.60 (m, 1 H), 8.21 (s, 1 H), 8.02 (d, J = 8.3 Hz, 1 H), 7.97–7.91 (m, 1 H), 7.66–7.58 (m, 2 H), 7.56 (t, J = 7.6 Hz, 1 H), 7.47 (t, J = 7.2 Hz, 1 H), 7.37–7.14 (m, 10 H), 5.74 (t, J = 4.8 Hz, 1 H), 5.15 (d, J = 5.8 Hz, 1 H), 2.18 (d, J = 4.8 Hz, 1 H). Representative peaks of the minor isomer: 8.73 (d, J = 8.2 Hz), 8.24 (s), 8.12 (d, J = 8.1 Hz), 7.72–7.65 (m, 2 H), 6.90 (d, J = 4.2 Hz), 5.62 (d, J = 9.3 Hz), 5.05 (d, J = 9.3 Hz), 2.57 (s). The mixture of two isomers: 13C NMR (100 MHz, CDCl3) δ 142.9, 141.9, 140.3, 139.2, 136.1, 134.8, 131.4, 131.2, 130.9, 130.7, 129.9, 129.7, 129.6, 128.9, 128.8, 128.7, 128.4, 128.2, 128.1, 128.0, 127.6, 127.5, 127.1, 127.1, 126.8, 126.8, 126.7, 126.64, 126.60, 126.54, 126.49, 126.46, 126.3, 126.0, 124.4, 124.3, 123.1, 122.5, 122.3, 77.1, 76.3, 55.8, 54.0. HRMS (ESI) m/z: [M + Na]+ calcd for 397.1563 C28H22ONa, found 397.1563.

2-(Naphtho[2,1-b]thiophen-4-yl)-2-phenylethan-1-ol (3al)

Overall, 37 mg of 3al was obtained from 1a (143 mg, 0.48 mmol) and 2l (30 mg, 0.2 mmol) in a 61% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 107.3–109.6 °C. 1H NMR (400 MHz, CDCl3) δ 8.31 (d, J = 8.0 Hz, 1 H), 8.02–7.94 (m, 2 H), 7.77 (s, 1 H), 7.64–7.50 (m, 3 H), 7.40 (d, J = 7.2 Hz, 2 H), 7.33 (t, J = 7.4 Hz, 2 H), 7.29–7.22 (m, 1 H), 4.63 (t, J = 6.9 Hz, 1 H), 4.46 (dd, J = 11.0, 7.0 Hz, 1 H), 4.36 (dd, J = 11.0, 6.9 Hz, 1 H), 1.80 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 139.8, 138.7, 136.5, 133.5, 131.4, 128.7, 128.6, 128.52, 128.51, 127.2, 126.3, 125.8, 125.5, 123.4, 122.3, 122.2, 65.4, 52.6. HRMS (ESI) m/z: [M + Na]+ calcd for 327.0814 C20H16OSNa, found 327.0810.

(E)-3-Styryl-2,3-dihydrobenzofuran (3am)[22]

Overall, 22 mg of 3am was obtained from 1a (143 mg, 0.48 mmol) and 2m (29 mg, 0.2 mmol) in a 50% yield; purified by column chromatography (100:1 PE/EA); white solid. mp 70.8–72.9 °C 1H NMR (500 MHz, CDCl3) δ 7.40 (d, J = 7.3 Hz, 2 H), 7.33 (t, J = 7.6 Hz, 2 H), 7.29–7.23 (m, 1 H), 7.18 (t, J = 7.4 Hz, 2 H), 6.91 (t, J = 7.4 Hz, 1 H), 6.86 (d, J = 7.9 Hz, 1 H), 6.58 (d, J = 15.7 Hz, 1 H), 6.32–6.20 (m, 1 H), 4.86–4.73 (m,1 H), 4.38–4.24 (m, 2 H). 13C NMR (125 MHz, CDCl3) δ159.9, 136.7, 131.8, 129.4, 129.3, 128.6, 127.6, 126.3, 125.0, 120.7, 109.7, 76.5, 46.4.

3-(Phenanthren-9-yl)-3-phenylpropan-1-ol (3an)

Overall, 31 mg of 3an was obtained from 1a (143 mg, 0.48 mmol) and 2n (32 mg, 0.2 mmol) in a 50% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 33.8–35.0 °C. 1H NMR (400 MHz, CDCl3) δ 8.69 (d, J = 8.2 Hz, 1 H), 8.65–8.61 (m, 1 H), 8.18 (d, J = 8.1 Hz, 1 H), 7.90–7.85 (m, 1 H), 7.74 (s, 1 H), 7.65–7.48 (m, 4 H), 7.34 (d, J = 7.3 Hz, 2 H), 7.23 (d, J = 9.1 Hz, 2 H), 7.15 (t, J = 7.3 Hz, 1 H), 4.98–4.91 (m, 1 H), 3.78–3.66 (m, 2 H), 2.58–2.80 (m, 1 H), 2.46–2.37 (m, 1 H), 1.53 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 144.0, 137.9, 131.5, 131.1, 130.9, 129.7, 128.52, 128.50, 128.1, 126.63, 126.59, 126.34, 126.32, 126.1, 125.1, 124.6, 123.1, 122.4, 60.9, 42.5, 38.7. HRMS (ESI) m/z: [M + Na]+ calcd for 335.1406 C23H20ONa, found 335.1405.

3-(6-Methylphenanthren-9-yl)-3-phenylpropan-1-ol (3ao)

Overall, 29 mg of 3ao was obtained from 1a (143 mg, 0.48 mmol) and 2o (35 mg, 0.2 mmol) in a 44% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 89.0–90.2 °C. 1H NMR (400 MHz, CDCl3) δ 8.65 (d, J = 8.1 Hz, 1 H), 8.50 (s, 1 H), 8.08 (d, J = 8.5 Hz, 1 H), 7.91–7.84 (m, 1 H), 7.70 (s, 1 H), 7.66–7.55 (m, 2 H), 7.40–7.32 (m, 3 H), 7.29–7.23 (m, 3 H), 7.17 (t, J = 7.2 Hz, 1 H), 4.95 (t, J = 7.5 Hz, 1 H), 3.84–3.66 (m, 2 H), 2.65–2.51 (m, 4 H), 2.49–2.40 (m, 1 H). 13C NMR (100 MHz, CDCl3) δ 144.2, 137.8, 135.8, 131.7, 131.0, 129.5, 129.0, 128.52, 128.48, 128.3, 128.1, 126.5, 126.3, 126.1, 124.5, 124.2, 122.9, 122.4, 61.1, 42.6, 38.7, 21.8. HRMS (ESI) m/z: [M + Na]+ calcd for 349.1563 C24H20ONa, found 349.1558.

3-Phenyl-3-(6-phenylphenanthren-9-yl)propan-1-ol (3ap)

Overall, 35 mg of 3ap was obtained from 1a (143 mg, 0.48 mmol) and 2p (47 mg, 0.2 mmol) in a 45% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 69.7–72.0 °C. 1H NMR (400 MHz, CDCl3) δ 8.91 (d, J = 1.3 Hz, 1 H), 8.75 (d, J = 7.9 Hz, 1 H), 8.27 (d, J = 8.7 Hz, 1 H), 7.94–7.88 (m, 1 H), 7.82–7.72 (m, 4 H), 7.68–7.59 (m, 2 H), 7.51 (t, J = 7.6 Hz, 2 H), 7.43–7.37 (m, 3 H), 7.29 (t, J = 7.6 Hz, 2 H), 7.19 (t, J = 7.3 Hz, 1 H), 5.07–4.96 (m, 1 H), 3.86–3.71 (m, 2 H), 2.65–2.57 (m, 1 H), 2.52–2.44 (m, 1 H), 1.55 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 144.1, 141.2, 138.8, 137.8, 131.8, 131.2, 130.3, 129.8, 128.9, 128.62, 128.58, 128.1, 127.5, 127.4, 126.8, 126.40, 126.38, 125.9, 125.2, 125.1, 122.4, 121.5, 61.0, 42.6, 38.7. HRMS (ESI) m/z: [M + Na]+ calcd for 411.1719 C29H24ONa, found 411.1710.

3-(6-Fluorophenanthren-9-yl)-3-phenylpropan-1-ol (3aq)

Overall, 28 mg of 3aq was obtained from 1a (143 mg, 0.48 mmol) and 2q (36 mg, 0.2 mmol) in a 43% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 91.6–93.5 °C. 1H NMR (400 MHz, CDCl3) δ 8.51 (dd, J = 5.8, 3.4 Hz, 1 H), 8.30 (dd, J = 11.0, 2.4 Hz, 1 H), 8.17 (dd, J = 9.1, 5.9 Hz, 1 H), 7.90 (dd, J = 5.9, 3.3 Hz, 1 H), 7.73 (s, 1 H), 7.63 (dd, J = 6.0, 3.2 Hz, 2 H), 7.34 (d, J = 7.4 Hz, 2 H), 7.31–7.24 (m, 3 H), 7.18 (t, J = 7.2 Hz, 1 H), 5.01–4.87 (m, 1 H), 3.87–3.66 (m, 2 H), 2.61–4.52 (m, 1 H), 2.48–2.40 (m, 1 H), 1.49 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 161.2 (d, 1JC–F = 245.7 Hz), 143.8, 137.6, 132.8 (d, 3JC–F = 8.1 Hz), 131.9, 129.12, 129.08, 128.58, 128.55, 128.0, 127.8 (d, 4JC–F = 1.4 Hz), 127.2, 126.9 (d, 3JC–F = 8.7 Hz), 126.44, 126.38, 124.3 (d, 4JC–F = 1.9 Hz), 122.6, 115.3 (d, 2JC–F = 23.2 Hz), 108.1 (d, 2JC–F = 21.9 Hz), 60.8, 42.7, 38.6. 19F NMR (376 MHz, CDCl3) δ −114.53. HRMS (ESI) m/z: [M + Na]+ calcd for 353.1312 C23H19OFNa, found 353.1304.

3-(6-Bromophenanthren-9-yl)-3-phenylpropan-1-ol (3ar)

Overall, 31 mg of 3ar was obtained from 1a (143 mg, 0.48 mmol) and 2r (48 mg, 0.2 mmol) in a 40% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 177.2–179.1 °C. 1H NMR (400 MHz, CDCl3) δ 8.82 (d, J = 1.8 Hz, 1 H), 8.57–8.55 (m, 1 H), 8.04 (d, J = 8.9 Hz, 1 H), 7.93–7.86 (m, 1 H), 7.77 (s, 1 H), 7.68–7.57 (m, 3 H), 7.32 (d, J = 7.3 Hz, 2 H), 7.30–7.23 (m, 2 H), 7.18 (t, J = 7.2 Hz, 1 H), 4.93–4.89 (m, 1 H), 3.83–3.67 (m, 2 H), 2.60–2.51 (m, 1 H), 2.50–2.37 (m, 1 H), 1.50 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 143.7, 137.6, 132.6, 131.9, 129.8, 129.6, 128.7, 128.62, 128.58, 128.1, 127.3, 126.7, 126.5, 126.4, 125.9, 125.5, 122.5, 120.7, 60.8, 42.5, 38.6. HRMS (ESI) m/z: [M + Na]+ calcd for 413.0511 C23H19OBrNa, found 413.0499.

3-(6-Bromo-5,7-dimethylphenanthren-9-yl)-3-phenylpropan-1-ol (3as)

Overall, 29 mg of 3as was obtained from 1a (143 mg, 0.48 mmol) and 2s (53 mg, 0.2 mmol) in a 35% yield; purified by column chromatography (10:1 PE/EA); white solid. mp 33.8–35.0 °C.1H NMR (400 MHz, CDCl3) δ 8.50 (d, J = 7.5 Hz, 1 H), 7.93 (s, 1 H), 7.91–7.84 (m, 1 H), 7.71 (s, 1 H), 7.61–7.50 (m, 2 H), 7.34 (d, J = 7.4 Hz, 2 H), 7.30–7.23 (m, 2 H), 7.18 (t, J = 7.2 Hz, 1 H), 4.95–4.84 (m, 1 H), 3.83–3.66 (m, 2 H), 3.11 (s, 3 H), 2.61–2.36 (m, 5 H), 1.55 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 144.0, 137.1, 135.7, 135.0, 132.8, 131.2, 130.9, 130.0, 129.8, 128.6, 128.2, 128.03, 128.01, 126.4, 126.1, 125.7, 124.8, 123.5, 60.9, 42.5, 38.9, 27.2, 25.1. HRMS (ESI) m/z: [M + Na]+ calcd for 441.0824 C25H23ONa, found 441.0819.

4-(Phenanthren-9-yl)-4-phenylbutan-1-ol (3at)

Overall, 10 mg of 3at was obtained from 1a (143 mg, 0.48 mmol) and 2t (35 mg, 0.2 mmol) in a 16% yield; purified by column chromatography (10:1 PE/EA); slightly yellow oil. 1H NMR (300 MHz, CDCl3) δ 8.78–8.69 (m, 1 H), 8.69–8.62 (m, 1 H), 8.16 (d, J = 8.0 Hz, 1 H), 7.96–7.86 (m, 1 H), 7.78 (s, 1 H), 7.70–7.50 (m, 4 H), 7.35 (d, J = 7.3 Hz, 2 H), 7.31–7.21 (m, 2 H), 7.16 (t, J = 7.2 Hz, 1 H), 4.72 (t, J = 7.5 Hz, 1 H), 3.72 (t, J = 6.5 Hz, 2 H), 2.47–2.20 (m, 2 H), 1.85–1.57 (m, 2 H). 13C NMR (75 MHz, CDCl3) δ 144.5, 138.1, 131.6, 131.2, 130.9, 129.6, 128.5, 128.4, 128.1, 126.6, 126.5, 126.3, 126.2, 126.0, 125.0, 124.5, 123.1, 122.4, 62.9, 46.4, 32.5, 31.3. HRMS (ESI) m/z: [M + H]+ calcd for 327.1743 C24H23O, found 327.1735.

Dimethyl-2-(2-(phenanthren-9-yl)-2-phenylethyl)malonate (5aa)

Overall, 66 mg of 5aa was obtained from 1a (143 mg, 0.48 mmol) and 5a (52 mg, 0.2 mmol) in an 80% yield; purified by column chromatography (10:1 PE/EA); slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 8.72 (d, J = 7.7 Hz, 1 H), 8.68–8.63 (m, 1 H), 8.15 (d, J = 7.9 Hz, 1 H), 7.93–7.88 (m, 1 H), 7.77 (s, 1 H), 7.69–7.50 (m, 4 H), 7.41–7.31 (m, 4 H), 7.24–7.15 (m, 1 H), 4.84–4.73 (m, 1 H), 3.77 (s, 3 H), 3.67 (s, 3 H), 3.53 (t, J = 7.4 Hz, 1 H), 3.02–2.73 (m, 2 H). 13C NMR (100 MHz, CDCl3) δ 169.9, 169.8, 142.8, 136.8, 131.4, 130.9, 129.8, 128.7, 128.6, 128.2, 126.71, 126.70, 126.68, 126.5, 126.2, 125.1, 124.4, 123.2, 122.4, 52.7, 52.5, 49.9, 44.0, 34.8. HRMS (ESI) m/z: [M + Na]+ calcd for 435.1567 C27H24O4Na, found 435.1593.

9-Cyclopropyl-9-phenyl-9,10-dihydrophenanthrene (5ab1)

Overall, 28 mg of 5ab1 was obtained from 1a (143 mg, 0.48 mmol) and 4b (29 mg, 0.2 mmol) in a 48% yield; purified by column chromatography (200:1 PE/EA); slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.91 (dd, J = 7.5, 1.0 Hz, 1 H), 7.79–7.68 (m, 2 H), 7.52–7.42 (m, 2 H), 7.36–7.32 (m, 4 H), 7.31–7.27 (m, 2 H), 7.25 (d, J = 7.8 Hz, 1 H), 7.19 (t, J = 7.1 Hz, 1 H), 3.67–3.64 (m, 1 H), 3.22–3.18 (m, 1 H), 1.55–1.37 (m, 1 H), 0.74–0.53 (m, 2 H), 0.24–0.04 (m, 2 H). 13C NMR (100 MHz, CDCl3) δ 143.6, 142.4, 135.6, 134.9, 134.3, 128.8, 128.6, 128.3, 127.4, 127.2, 127.07, 127.06, 126.8, 125.8, 124.0, 123.3, 46.0, 41.9, 20.0, 2.9, −0.3. HRMS (ESI) m/z: [M + Na]+ calcd for 319.1457 C23H20Na, found 319.1452.

9-Cyclopropyl-9,10-dihydrophenanthrene (5ab2)

Overall, 8 mg of 5ab2 was obtained from 1a (143 mg, 0.48 mmol) and 4b (29 mg, 0.2 mmol) in a 17% yield; purified by column chromatography (200:1 PE/EA); slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.77 (t, J = 7.0 Hz, 2 H), 7.50 (d, J = 7.2 Hz, 1 H), 7.39–7.27 (m, 4 H), 7.26–7.21 (m, 1 H), 3.10–3.05 (m, 1 H), 2.92–2.68 (m, 1 H), 2.05–1.99 (m, 1 H), 0.95–0.80 (m, 1 H), 0.63–0.44 (m, 2 H), 0.34–0.29 (m, 1 H), 0.27–0.21 (m, 1 H). 13C NMR (100 MHz, CDCl3) δ 140.5, 136.5, 134.3, 133.9, 128.5, 127.5, 127.4, 127.2, 127.0, 126.9, 123.8, 123.5, 43.9, 35.3, 14.9, 5.0, 3.6. GC–MS (EI) m/z: 220.1, 205.0, 191.0, 179.1.

9-Cyclopropylphenanthrene (5ab3)[23]

Overall, 13 mg of 5ab3 was obtained from 1a (143 mg, 0.48 mmol) and 4b (29 mg, 0.2 mmol) in a 30% yield; purified by column chromatography (200:1 PE/EA); white solid. mp 64.9–66.6 °C. 1H NMR (400 MHz, CDCl3) δ 8.76–8.73 (m, 1 H), 8.68 (d, J = 7.9 Hz, 1 H), 8.56–8.52 (m, 1 H), 7.89–7.81 (m, 1 H), 7.75–7.66 (m, 2 H), 7.66–7.55 (m, 3 H), 2.44–2.31 (m, 1 H), 1.18–1.08 (m, 2 H), 0.91–0.81 (m, 2 H). 13C NMR (100 MHz, CDCl3) δ 137.3, 132.7, 131.9, 130.4, 129.6, 128.2, 126.54, 126.46, 126.3, 126.01, 125.04, 124.5, 122.9, 122.4, 13.8, 6.2.

Larger Synthesis of Phenanthrene 3aa

To a 100 mL flame-dried screw-capped test tube with a stir bar, aryne precursor 1a (3.58 g, 12 mmol), vinyl epoxide 2a (0.73 g, 5 mmol), and MeCN (20 mL) were added. Then, CsF (3.04 g, 20 mmol) was added to the abovementioned solution. The mixture was stirred at 50 °C for 6 h. Most of the reaction mixture was evaporated, and the residue was purified by column chromatography (10:1 PE/EA) to afford the desired 3aa (776 mg, 52% yield).

Synthesis of Functionalized Phenanthrene 6

To a 25 mL flame-dried screw-capped test tube with a stir bar, 3aa (60 mg, 0.2 mmol) and DMSO (2 mL) were added. Then, Cs2CO3 (65 mg, 0.2 mmol) was added to the abovementioned solution, and the mixture was stirred at 150 °C for 2 h. Most of the reaction mixture was evaporated, and the residue was purified by column chromatography (10:1 PE/EA) to afford the desired phenanthren-9-yl(phenyl)methanone 6(24) (48 mg, 85% yield) as a slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 8.76 (dd, J = 14.5, 8.4 Hz, 2 H), 8.13 (d, J = 8.2 Hz, 1 H), 7.95 (t, J = 8.2 Hz, 2 H), 7.90 (d, J = 7.8 Hz, 1 H), 7.86 (s, 1 H), 7.79–7.56 (m, 5 H), 7.48 (t, J = 7.7 Hz, 2 H). 13C NMR (100 MHz, CDCl3) δ 197.9, 138.1, 135.3, 133.3, 131.2, 130.6, 130.4, 130.0, 129.5, 129.3, 129.1, 128.5, 128.3, 127.2, 127.13, 127.09, 126.6, 122.9, 122.7.

Synthesis of Functionalized Phenanthrene 7

To a 25 mL flame-dried screw-capped test tube with a stir bar, 3aa (60 mg, 0.2 mmol), propargyl bromide (35 mg, 0.3 mmol), and dry THF (2 mL) were added. Then, NaH (14 mg, 0.6 mmol) was added to the abovementioned solution, and the mixture was stirred at 45 °C for 12 h. Most of the reaction mixture was evaporated, and the residue was purified by column chromatography (10:1 PE/EA) to afford the desired 9-(1-phenyl-2-(prop-2-yn-1-yloxy)ethyl)phenanthrene 7 (59 mg, 88% yield) as a slightly yellow solid. mp 81.7–83.8. 1H NMR (400 MHz, CDCl3) δ 8.76 (d, J = 8.2 Hz, 1 H), 8.70 (d, J = 7.7 Hz, 1 H), 8.15 (d, J = 8.2 Hz, 1 H), 7.95 (d, J = 7.4 Hz, 1 H), 7.83 (s, 1 H), 7.69–7.62 (m, 3 H), 7.57 (t, J = 7.5 Hz, 1 H), 7.41 (d, J = 7.5 Hz, 2 H), 7.33 (t, J = 7.5 Hz, 2 H), 7.28–7.22 (m, 1 H), 5.17 (t, J = 6.9 Hz, 1 H), 4.42 (t, J = 8.4 Hz, 1 H), 4.35–4.21 (m, 3 H), 2.60–2.50 (m, 1 H). 13C NMR (100 MHz, CDCl3) δ 141.6, 134.9, 131.5, 131.1, 130.9, 129.8, 128.6, 128.5, 126.7, 126.6, 126.4, 126.1, 125.9, 124.5, 123.1, 122.4, 79.7, 74.7, 72.8, 58.2, 46.6. HRMS (ESI) m/z: [M + Na]+ calcd for 359.1406 C25H20ONa, found 359.1407.

Synthesis of Functionalized Phenanthrene 8

To a 25 mL flame-dried screw-capped test tube with a stir bar, 3aa (60 mg, 0.2 mmol), 4-dimethylaminopyridine (5 mg, 0.04 mmol), dichloromethane (DCM) (2 mL), and Et3N (41 mg, 0.4 mmol) were added. Then, benzoyl chloride (42 mg, 0.3 mmol) was added to the abovementioned solution, and the mixture was stirred at room temperature for 2 h. Most of the reaction mixture was evaporated, and the residue was purified by column chromatography (10:1 PE/EA) to afford the desired 2-(phenanthren-9-yl)-2-phenylethyl benzoate 8 (75 mg, 93% yield) as a white solid. mp 84.6–85.4 °C. 1H NMR (400 MHz, CDCl3) δ 8.76 (d, J = 8.1 Hz, 1 H), 8.70 (d, J = 8.0 Hz, 1 H), 8.20 (d, J = 8.0 Hz, 1 H), 7.98 (d, J = 7.4 Hz, 2 H), 7.93 (d, J = 7.4 Hz, 1 H), 7.83 (s, 1 H), 7.70–7.61 (m, 3 H), 7.60–7.56 (m, 1 H), 7.52 (t, J = 7.9 Hz, 1 H). 7.44 (d, J = 7.4 Hz, 2 H), 7.39 (t, J = 7.7 Hz, 2 H), 7.33 (t, J = 7.5 Hz, 2 H), 7.27–7.23 (m, 1 H), 5.34 (t, J = 7.3 Hz, 1 H), 5.17 (dd, J = 11.1, 7.1 Hz, 1 H), 5.06 (dd, J = 11.1, 7.5 Hz, 1 H). 13C NMR (100 MHz, CDCl3). δ 13C NMR (100 MHz, CDCl3) δ 166.5, 140.9, 134.5, 132.9, 131.4, 131.0, 130.9, 130.5, 130.0, 129.9, 129.6, 128.8, 128.69, 128.65, 128.5, 128.3, 127.0, 126.77, 126.75, 126.6, 126.3, 125.7, 124.5, 123.2, 122.4, 67.3, 45.8. HRMS (ESI) m/z: [M + Na]+ calcd for 425.1512 C29H22O2Na, found 425.1511.

Synthesis of Functionalized Phenanthrene 9

To a 25 mL flame-dried screw-capped test tube with a stir bar, 3aa (60 mg, 0.2 mmol), 4-dimethylaminopyridine (5 mg, 0.04 mmol), DCM (2 mL), and Et3N (41 mg, 0.4 mmol) and were added. Then, 4-methylbenzenesulfonyl chloride (57 mg, 0.3 mmol) was added to the abovementioned solution, and the mixture was stirred at room temperature for 2 h. Most of the reaction mixture was evaporated, and the residue was purified by column chromatography (10:1 PE/EA) to afford the desired 2-(phenanthren-9-yl)-2-phenylethyl 4-methylbenzenesulfonate 9 (77 mg, 85% yield) as a white solid. mp 151.7–152.8 °C. 1H NMR (400 MHz, CDCl3) δ 8.72 (d, J = 8.2 Hz, 1 H), 8.67 (d, J = 8.0 Hz, 1 H), 7.98 (d, J = 8.3 Hz, 1 H), 7.81 (d, J = 7.6 Hz, 1 H), 7.73–7.58 (m, 5 H), 7.57 (s, 1 H), 7.52 (t, J = 7.6 Hz, 1 H), 7.34–7.21 (m, 5 H), 7.17 (d, J = 7.9 Hz, 2 H), 5.18 (t, J = 7.1 Hz, 1 H), 4.87 (t, J = 8.8 Hz, 1 H), 4.77 (dd, J = 9.6, 7.5 Hz, 1 H), 2.38 (s, 3 H). 13C NMR (100 MHz, CDCl3) δ 144.5, 139.3, 133.0, 132.6, 131.0, 130.8, 130.4, 129.8, 129.6, 128.6, 128.5, 128.3, 127.6, 127.1, 126.70, 126.66, 126.6, 126.2, 125.7, 124.0, 123.1, 122.3, 71.6, 45.7, 21.4. HRMS (ESI) m/z: [M + Na]+ calcd for 475.1338 C29H24O3SNa, found 475.1338.

Synthesis of Functionalized Phenanthrene 10

To a 25 mL flame-dried screw-capped test tube with a stir bar, 9 (90 mg, 0.2 mmol) and dry THF (2 mL) were added. Then, NaH (48 mg, 2 mmol) was added to the abovementioned solution, and the mixture was stirred at 60 °C for 12 h. Most of the reaction mixture was evaporated, and the residue was purified by column chromatography (10:1 PE/EA) to afford the desired 9-(1-phenylvinyl)phenanthrene 10(25) (50 mg, 90% yield) as a white solid. mp 128.3–130.7 °C. 1H NMR (400 MHz, CDCl3) δ 8.77 (dd, J = 8.0, 4.9 Hz, 2 H), 7.96 (d, J = 7.4 Hz, 1 H), 7.89 (d, J = 8.2 Hz, 1 H), 7.82 (s, 1 H), 7.76–7.62 (m, 3 H), 7.53–7.43 (m, 3 H), 7.37–7.28 (m, 3 H), 6.10 (d, J = 1.1 Hz, 1 H), 5.57 (d, J = 1.1 Hz, 1 H). 13C NMR (100 MHz, CDCl3) δ 148.5, 140.6, 138.3, 131.6, 131.0, 130.5, 130.3, 128.6, 128.4, 127.82, 127.75, 127.3, 126.8, 126.6, 126.54, 126.46, 126.3, 122.7, 122.5, 116.2.

Synthesis of Functionalized Phenanthrene 11

To a 25 mL flame-dried screw-capped test tube with a stir bar, 9 (90 mg, 0.2 mmol) and MeCN (2 mL) were added. Then, benzylamine (43 mg, 0.4 mmol) was added to the abovementioned solution, and the mixture was stirred at 100 °C for 24 h. Most of the reaction mixture was evaporated, and the residue was purified by column chromatography (10:1 PE/EA) to afford the desired N-benzyl-2-(phenanthren-9-yl)-2-phenylethan-1-amine 11 (48 mg, 62% yield) as a white solid. mp 95.9–98.6 °C. 1H NMR (400 MHz, CDCl3) δ 8.74 (d, J = 8.2 Hz, 1 H), 8.69 (d, J = 7.8 Hz, 1 H), 8.17 (d, J = 8.2 Hz, 1 H), 7.87 (d, J = 7.2 Hz, 1 H), 7.72–7.60 (m, 4 H), 7.56 (t, J = 7.5 Hz, 1 H), 7.41–7.27 (m, 9 H), 7.22 (t, J = 7.1 Hz, 1 H), 5.08 (t, J = 7.1 Hz, 1 H), 3.99–3.87 (m, 2 H), 3.55 (dd, J = 11.7, 7.4 Hz, 1 H), 3.40 (dd, J = 11.8, 7.0 Hz, 1 H), 1.80 (s, 1 H). 13C NMR (100 MHz, CDCl3) δ 142.7, 140.1, 136.0, 131.4, 131.2, 131.0, 129.8, 128.6, 128.5, 128.4, 128.2, 128.1, 126.9, 126.64, 126.63, 126.6, 126.4, 126.2, 125.0, 124.5, 123.1, 122.4, 53.8, 46.8. HRMS (ESI) m/z: [M + H]+ calcd for 388.2060 C29H26N, found 388.2056.

Synthesis of Functionalized Phenanthrene 12

To a 25 mL flame-dried screw-capped test tube with a stir bar, 9 (90 mg, 0.2 mmol) and MeCN (2 mL) were added. Then, NaN3 (26 mg, 0.4 mmol) was added to the abovementioned solution, and the mixture was stirred at 100 °C for 24 h. Most of the reaction mixture was evaporated, and the residue was purified by column chromatography (10:1 PE/EA) to afford the desired 9-(2-azido-1-phenylethyl)phenanthrene 12 (50 mg, 78% yield) as a slightly yellow oil. 1H NMR (400 MHz, CDCl3) δ 8.76 (d, J = 8.2 Hz, 1 H), 8.70 (d, J = 8.0 Hz, 1 H), 8.10 (d, J = 8.2 Hz, 1 H), 7.98–7.91 (m, 1 H), 7.74 (s, 1 H), 7.72–7.62 (m, 3 H), 7.58 (t, J = 7.2 Hz, 1 H), 7.40 (d, J = 7.3 Hz, 2 H), 7.34 (t, J = 7.4 Hz, 2 H), 7.31–7.26 (m, 1 H), 5.04 (t, J = 7.3 Hz, 1 H), 4.16 (dd, J = 12.4, 7.0 Hz, 1 H), 4.08 (dd, J = 12.4, 7.7 Hz, 1 H). 13C NMR (100 MHz, CDCl3) δ 141.0, 134.5, 131.2, 131.0, 130.7, 129.9, 128.8, 128.7, 128.3, 127.2, 126.80, 126.78, 126.7, 126.3, 125.5, 124.2, 123.3, 122.4, 55.7, 46.5. HRMS (ESI) m/z: [M + Na]+ calcd for 346.1315 C22H17N3Na, found 346.1312.