Investigation of the Selectivity of the Palladium-Catalyzed Aroylation and Arylation of Stannyl Glycals with Aroyl Chlorides.

The selectivity of the palladium-catalyzed aroylation and arylation of 1-tributylstannyl glycals with aroyl chlorides was investigated. The selectivity was controlled by the palladium catalyst, and high selectivity was achieved via ligand modification of the palladium catalyst. The reaction catalyzed by Pd(OAc)2 provided aroyl C-glycals with high selectivity, whereas the reaction catalyzed by Pd(PPh3)4 produced aryl C-glycals with diminished selectivity. The scope and limitation of the selectivity in this reaction are discussed.

Introduction

The palladium-catalyzed cross-coupling of acyl halides is a useful reaction for the preparation of carbonyl compounds.[1,2] The intermediate of this reaction, acylpalladium complex, leads to the desired carbonyl compound, whereas a decarbonylated compound is obtained if decarbonylation of the intermediate occurs.[3,4] In the Stille reaction of aroyl chlorides, it was reported that the addition of Et3SiH was effective for aromatic ketone synthesis,[2a] and the use of bis(di-tert-butylchlorophosphine)palladium(II) dichloride was beneficial for preparing a variety of diarylketones.[2c] 1-(2-Pyridylethynyl)-2-(2-thienylethynyl)benzene was also reported as an efficacious ligand in the palladium-catalyzed Heck reaction of acid chlorides for synthesizing alkynones.[2b] Conversely, a decarbonylative cross-coupling reaction was reported to be catalyzed by Pd0/Brettphos,[4b] and decarbonylation of the Mizoroki–Heck-type reaction in the presence of (PhCH2)Bu3NCl has been described.[4i,4j] Thus, the selectivity of the palladium-catalyzed cross-coupling of acyl halides remains incompletely understood, and further investigations are needed.

Aryl C-glycosides are naturally occurring compounds, and many synthetic analogues have been reported to possess a variety of biological activities.[5] The palladium-catalyzed arylation of 1-tributylstannyl glycal is a useful reaction for obtaining aryl C-glycoside analogues, and it has been used for natural product synthesis.[6] In the course of research dedicated to expanding the synthetic utility of glycals,[7] a novel type of aroyl C-glycoside that is expected to display a variety of biological activities was designed. To investigate the biological roles of aroyl C-glycoside, the elaboration of its synthetic method was required because only limited examples have been reported.[8,9] We found that the selectivity of the palladium-catalyzed aroylation and arylation of 1-tributylstannyl glycals 1 was influenced by the palladium catalyst. In this study, we demonstrated that aroyl C-glycals can be obtained in a selective manner by modifying the ligand of the catalyst, whereas the selectivity for synthesizing aryl C-glycals was diminished.[10]

Results and Discussion

The study was initiated by optimizing the reaction of triisopropylsilyl (TIPS)-protected 1-tributylstannyl d-glucal 1a with aroyl chloride 2 to obtain aroyl C-glucal 3, as presented in Table (0.10 mmol scale). As reported previously,[7] we optimized the cross-coupling reaction condition for benzyl C-glycal synthesis as 10 mol % PdCl2[1,2-bis(diphenylphosphino)ethane (dppe)], 2 equiv of Na2CO3, and 3 equiv of benzyl bromide in refluxing toluene. To elaborate the synthetic utility of this reaction condition, 1.2 equiv of benzoyl chloride (2a) was reacted with 1-tributylstannyl d-glucal 1a in refluxing toluene in the presence of 10 mol % PdCl2(dppe), which resulted in almost no reaction (entry 1). When Na2CO3 was omitted, trace amounts of aroyl C-glucal 3a and aryl C-glucal 4a were observed (entry 2). However, the reaction remained sluggish, and a large amount of the starting d-glucal 1a was not consumed. The use of PdCl2(CH3CN)2 has been reported to be effective for aroyl C-glucal synthesis,[8] and it increased the yield 3a (20%, entry 3). As this reaction remained sluggish with several byproducts, further optimization was required. When Na2CO3 was omitted and the amount of 2 was increased (3 equiv), the reaction proceeded smoothly, and the desired aroyl adduct 3a was obtained at 70% yield (entry 4). As 4-substituted aroyl chlorides 2b and 2c under this reaction led to poor results (entries 5 and 6), the effects of the palladium catalyst were examined in the reaction with aroyl chloride 2b. The use of PdCl2(PhCN)2 led to comparable results as PdCl2(CH3CN)2 (entry 7). The use of bidentate phosphine ligands, such as PdCl2(dppe) or PdCl2[1,1′-bis(diphenylphosphino)ferrocene (dppf)], did not improve the yield even after 25 h (entries 8 and 9). When PdCl2 was employed, aroyl C-d-glucal 3b was isolated at 17% yield (entry 10). The use of PdCl2 was reported for synthesizing aromatic ketone from acyl chlorides and arylboronic acid.[2e] The counter ion of the palladium catalyst is critical because the use of Pd(OAc)2 improved the yield of 3b (57%) with trace amounts of 4b (entry 11). The reaction with PdCl2 required a longer time than that with Pd(OAc)2, which completed within less than 1 h. The reaction catalyzed by Pd(OAc)2 at a scale of 1.0 mmol was performed to confirm the reproducibility of the reaction with a similar yield of 3b (66%), and a trace amount of 4b was observed in this reaction. The addition of CuI was not beneficial for the reaction (entry 12).[11] This result led us to examine Pd(TFA)2, which resulted in obtaining 3b at diminished yield (entry 13). Among the olefin ligands examined, Pd(acac)2 provided the best yield, which was comparable to that of Pd(OAc)2 (entries 11 and 16). The nitrogen ligand also provided 3b selectively in modest yields (entries 19–21). The monodentate phosphine ligand gave the opposite result. The use of Pd(PPh3)4 provided aryl C-d-glucal 4b selectively (71% yield) with a trace amount of aroyl adduct 3b (entry 22). It is interesting to note that Pd(PPh3)4 was reported to catalyze the synthesis of ketone from acid chloride and boronic acids.[2h] The use of PdCl2(PPh3)2 diminished the yield of 4b. The arsine ligand led to diminished selectivity.

Table 1

Influence of Palladium Catalysts on the Selectivity of 3 and 4a

	2
entry		Y	equiv	catalyst (10 mol %)	additives (equiv)	yield of 3 (%)b	yield of 4 (%)b	reaction time (h)
1	2a	H	1.2	PdCl2(dppe)	Na2CO3 (3 equiv)	0	0	30
2	2a	H	1.2	PdCl2(dppe)	none	<1	<1	30
3	2a	H	1.2	PdCl2(CH3CN)2	Na2CO3 (3 equiv)	20 (3a)	<1	7
4	2a	H	3	PdCl2(CH3CN)2	none	70 (3a)	<1	1.5
5	2b	CO2Me	3	PdCl2(CH3CN)2	none	22 (3b)	<1	5.5
6	2c	CN	3	PdCl2(CH3CN)2	none	24 (3c)	13 (4c)	1
7	2b	CO2Me	3	PdCl2(PhCN)2	none	21 (3b)	<1	5
8	2b	CO2Me	3	PdCl2(dppe)	none	15 (3b)	2 (4b)	25
9	2b	CO2Me	3	PdCl2(dppf)	none	12 (3b)	3 (4b)	25
10	2b	CO2Me	3	PdCl2	none	17 (3b)	0 (4b)	25
11	2b	CO2Me	3	Pd(OAc)2	none	57 (3b)	<1	0.5
12	2b	CO2Me	3	Pd(OAc)2	CuI (2 equiv)	44 (3b)	6 (4b)	1.5
13	2b	CO2Me	3	Pd(TFA)2	none	19 (3b)	<1	3
14	2b	CO2Me	3	[PdCl2(allyl)2]2	none	12 (3b)	3 (4b)	5
15	2b	CO2Me	3	Pd2(dba)3	none	<1	0	29.5
16	2b	CO2Me	3	Pd(acac)2	none	44 (3b)	<1	3
17	2b	CO2Me	3	PdCl2(cod)	none	20 (3b)	<1	3
18	2b	CO2Me	3	PdCl2(nbd)	none	26 (3b)	<1	6.5
19	2b	CO2Me	3	Pd2(TMEDA)2	none	24 (3b)	0	29
20	2b	CO2Me	3	Pd2(EDA)2	none	28 (3b)	0	30.5
21	2b	CO2Me	3	PdCl2(2,2′-bipyridine)	none	36 (3b)	0	30.5
22	2b	CO2Me	3	Pd(PPh3)4	none	<1	71 (4b)	7.5
23	2b	CO2Me	3	PdCl2(PPh3)2	none	4 (3b)	38 (4b)	3
24	2b	CO2Me	3	Pd(AsPh3)4	none	12 (3b)	8 (4b)	4.5

The reaction was performed using 1a (0.10 mmol), 2 (0.30 mmol), and Pd catalyst (0.010 mmol) in toluene (5 mL) under reflux.

Isolated yield.

As the use of Pd(OAc)2 provides aroyl C-d-glucal 3b and Pd(PPh3)4 produces aryl C-d-glucal 4b in a selective manner, the influence of 4-substituents of aroyl chloride on selectivity was investigated, as presented in Table . When benzoyl chloride (2a) was reacted, aroyl adduct 3a was obtained at 89% yield, which is better than that catalyzed by PdCl2(CH3CN)2 (Table , entry 4). 4-Toluoyl adduct 3d was also formed in a selective manner. When 4-cyanobenzoyl chloride (2c) was reacted with Pd(OAc)2, the selectivity was diminished, and aroyl C-d-glucal 3c and aryl C-d-glucal 4c were isolated at yields of 48 and 22%, respectively. Because there are no significant differences in the electrostatic nature of the aromatic ring substituted with the methoxycarbonyl or cyano group, it remains unclear why such diminished selectivity was observed. Similar high selectivity was observed when 1-tributylstannyl d-galactal 1b was reacted with aroyl chlorides 2 catalyzed by Pd(OAc)2 (Table ). In particular, the benzoyl and 4-toluoyl adducts 5a and 5d were obtained with greater than 80% yield. Thus, it is clear that the reaction catalyzed by Pd(OAc)2 proceeded selectively and required less than 1 h to complete, excluding the reaction of 1a and 2c.

Table 2

Reactions of 1-Tributylstannyl D-Glucal 1a or D-Galactal 1b with Aroyl Chlorides 2a–da

			Pd(OAc)2			Pd(PPh3)4
1	2	Y	yield of aroyl C-glycal (%)b	yield of aryl C-glycal (%)b	reaction time (h)	yield of aroyl C-glycal (%)b	yield of aryl C-glycal (%)b	reaction time (h)
1a	2a	H	89 (3a)	<1 (4a)	1	0 (3a)	67 (4a)	11
	2b	4-CO2Me	57 (3b)	<1 (4b)	0.5	<1 (3b)	71 (4b)	7.5
	2c	4-CN	48 (3c)	22 (4c)	4	<1 (3c)	56 (4c)	34
	2d	4-Me	54 (3d)	0 (4d)	1	30 (3d)	<1 (4d)	7
1b	2a	H	82 (5a)	0 (6a)	1	25 (5a)	50c(6a)	4.5
	2b	4-CO2Me	74 (5b)	0 (6b)	1	25 (5b)	<1 (6b)	4.5
	2c	4-CN	62 (5c)	<1 (6c)	1	46 (5c)	16c(6c)	28
	2d	4-Me	88 (5d)	0 (6d)	0.5	27 (5d)	30c(6d)	25

The reaction was performed using 1c (0.10 mmol), 2 (0.30 mmol), and Pd catalyst (0.010 mmol %) in refluxing toluene (5 mL).

Isolated yield.

Product was isolated with an inseparable impurity.

When Pd(PPh3)4 was used as a catalyst, an unsubstituted aryl C-d-glucal (4a) and its analogue with an electron-withdrawing substituent (4c) were selectively formed. These reactions required longer times to complete. The reactions with benzoyl chloride (2a) resulted in high selectivity with both catalysts. Compounds 4a and 4c have been reported, and both compounds exhibited identical spectra, as previously reported.[6j,12] Aroyl chloride with an electron-donating substituent exhibited the opposite selectivity. 4-Toluoyl C-d-glucal 3d was isolated selectively regardless of the palladium catalyst used. It was reported that electron-rich aryl esters primarily formed ketone in nickel-catalyzed coupling of aryl esters and arylboronic acid.[4e] When the reaction of 1-tributylstannyl d-galactal 1b and 2b was catalyzed by Pd(PPh3)4, only a trace amount of aryl C-d-galactal 6b was formed, and the corresponding aroyl adduct 5b was isolated at 25% yield. Furthermore, selectivity was lost when 2a and 2c were catalyzed by Pd(PPh3)4. In fact, the reaction of 1b catalyzed by Pd(PPh3)4 was not clean, and aryl C-d-galactals 6a, 6c, and 6d contained inseparable impurities. The reaction of 4-toluoyl chloride (2d) catalyzed by Pd(PPh3)4 resulted in the formation of aryl C-d-galactal 6d. This was an unexpected result because other stannyl glycals 1a, 1c, and 1d provided aroyl C-glycals 3d, 7d, and 9d selectively (Tables and 3; vide infra).

Table 3

Reactions of 6-Deoxy-l-glucal 1c or L-fucal 1d and Aroyl Chlorides 2a–da

			Pd(OAc)2			Pd(PPh3)4
1	2	Y	yield of aroyl C-glycal (%)b	yield of aryl C-glycal (%)b	reaction time (h)	yield of aroyl C-glycal (%)b	yield of aryl C-glycal (%)b	reaction time (h)
1c	2a	H	75 (7a)	0 (8a)	1	12, 53c(7a)	36e, 18c,e(8a)	4, 5c
	2b	4-CO2Me	76 (7b)	<1 (8b)	2	<1, <1c(7b)	34, 19c(8b)	2, 4c
	2c	4-CN	49 (7c)	8d(8c)	2	4, 6c(7c)	32d, 84c,d(8c)	8, 4.5c
	2d	4-Me	81 (7d)	0 (8d)	1	39 (7d)	<1 (8d)	6
1d	2a	H	84 (9a)d	0 (10a)	0.5	38 (9a)d	49 (10a)d	5
	2b	4-CO2Me	90 (9b)	<1 (10b)	2	44 (9b)	21 (10b)	8
	2c	4-CN	57 (9c)	<1 (10c)	1	58 (9c)	19 (10c)	7
	2d	4-Me	91 (9d)	0 (10d)	1	55 (9d)	0 (10d)	4.5

The reaction was performed using 1b (0.10 mmol), 2 (0.30 mmol), and Pd catalyst (0.010 mmol) in refluxing toluene (5 mL) unless otherwise noticed.

Isolated yield.

The palladium catalyst was used at 0.020 mmol.

A small amount of the adduct decomposed after several days.

Product was isolated with an inseparable impurity.

The selectivity with 6-deoxy-1-tributylstannyl-l-glucal 1c and 1-tributylstannyl-l-fucal 1d was then investigated under the same reaction condition, as described in Table . The selective formation of aroyl 6-deoxy-C-l-glucals 7a–7d and aroyl C-l-fucals 9a–9d was observed when Pd(OAc)2 was employed as a catalyst for all aroyl chlorides (2a–2d) examined. These reactions completed in less than 2 h. The use of 2c led to adducts 7c and 9c with lower yields than those of the aroyl C-glycals 7 and 9. The selectivity was lower in the reaction between 1c and 2c than the reactions of 1c with 2a, 2b, or 2d. However, the selectivity was better than that of the reaction of 1a with 2c (Table ). As reported previously, l-fucal analogues tend to exhibit instability,[7] and a small amount of aroyl adduct 9a decomposed after several days of standing at room temperature, as confirmed by the 1H NMR spectra (see the Supporting Information). As the corresponding aryl analogue 10a also displayed instability, the selectivity of adducts 9a and 10a cannot be discussed.

The selectivity was diminished when Pd(PPh3)4 was utilized in this reaction. Although aryl 6-deoxy-C-l-glucals 8a–8c were formed preferably when 2a–2c were used in reactions catalyzed by Pd(PPh3)4, the isolated yields and selectivity were lower than those of 4a–4c (Table ). 8a, 8b, and 8c were isolated with yields of 36, 34, and 32%, respectively. The amount of the palladium catalyst was revealed to affect the yield of the reaction. When 20 mol % Pd(PPh3)4 was used, 8b was obtained at lower yield, whereas the yield of 8c was greatly improved to 84%. Conversely, the use of 20 mol % Pd(PPh3)4 reversed the selectivity for 7a and 8a. Compound 8c displayed instability, and a small amount of 8c decomposed after several days at room temperature, which was confirmed by the 1H NMR spectra (see the Supporting Information). The reaction of 1c with 2c catalyzed by Pd(PPh3)4 was messy, and the adduct 8a contained an inseparable impurity. The reaction of 1-tributylstannyl-l-fucal 1d catalyzed by Pd(PPh3)4 lost selectivity when 2b and 2c were used. In these reactions, the formation of aroyl adducts 9b and 9c was preferred.

Again, when an electron-releasing 4-toluoyl chloride (2d) was reacted in the presence of Pd(PPh3)4, only aroyl C-glycal 7d or 9d was isolated with a modest yield.

The high selectivity associated with the use of Pd(OAc)2 and diminished selectivity with Pd(PPh3)4 could be explained by the rates of transmetallation and decarbonylation of acylpalladium complexes. It appears that under ligand-free conditions, such as the use of Pd(OAc)2, transmetallation proceeds preferably to provide aroyl adducts, whereas decarbonylation is accelerated when a sterically bulkier ligand, such as triphenylphosphine, was used as the palladium ligand. The higher trans effect of phosphine also accelerated decarbonylation by promoting the creation of the vacant site necessary for decarbonylation.[13]

An electron-releasing group at the 4-position of aroyl chloride is an important factor for selective aroylation. This could be explained by the stronger Ar–CO bond with the four-electron-releasing group.[14]

Conclusions

In conclusion, the selectivity of the palladium-catalyzed aroylation and arylation of 1-tributylstannyl glycals 1a–1d with aroyl chlorides 2a–2d was investigated. The reaction catalyzed by Pd(OAc)2 provided aroyl C-glycals selectively with high yields for all 1-tributylstannyl glycals (1a–1d) examined. Although aryl C-d-glucals 4a–4c were selectively obtained with the reaction of four-electron-withdrawing or unsubstituted aroyl chlorides (2a–2c) with 1-tributylstannyl d-glucal 1a catalyzed by Pd(PPh3)4, the selectivity was diminished or lost when the reaction was performed with other 1-tributylstannyl glycals (1b–1d). When the reaction was performed with electron-releasing 2d, the selective formation of aroyl adducts was observed regardless of the catalyst used. However, the selectivity was lost when the reaction of 2d and stannyl d-galactal 1c was catalyzed by Pd(PPh3)4. Thus, further research on selective arylation is required.

Experimental Section

All reactions were performed in glass flasks under N2. Starting reagents were purchased from commercial suppliers and used without further purification, unless otherwise specified. Chromatographic elution was conducted under continuous monitoring by thin-layer chromatography using silica gel 60F254 (Merck & Co., Inc.) as the stationary phase and the elution solvent used in column chromatography as the mobile phase. A UV detector was used for detection. Silica gel SK-85 (230–400 mesh) or silica gel SK-34 (70–230 mesh), both of which were manufactured by Merck & Co., Inc., was used as the column-packing silica gel. 1H and 13C NMR spectra were obtained on Varian Unity 400 MHz or JEOL JNM-GSX400 MHz spectrometers. Spectra were recorded in the indicated solvent at ambient temperature, and chemical shifts were reported in ppm (δ) relative to the solvent peak. Resonance patterns are represented by the following notations: br (broad signal), s (singlet), d (doublet), t (triplet), q (quartet), and m (multiplet). HRMS was conducted using an LC–MS system consisting of a Waters Xevo Quadropole-ToF MS and an Acquity UHPLC system.

General Procedure of Palladium-Catalyzed Coupling Reactions

To a solution of 1-tributylstannyl glycal 1(7) (0.10 mmol) in toluene (5 mL) was added palladium catalyst (0.01 mmol), followed by aroyl chloride 2 (0.30 mmol). The reaction mixture was stirred at reflux for the times indicated in Tables and 3. The solution was concentrated under reduced pressure. Column chromatography afforded the coupled product.

2,6-Anhydro-3-deoxy-1-phenyl-4,5,7-tris-O-[tri(propan-2-yl)silyl]-d-arabino-hept-2-enose (3a)

The reaction was performed with 1a (90 mg, 0.10 mmol), 2a (35 μL, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) to provide 3a (64.4 mg, 89%). [α]D23 = −7.4 (c = 0.2, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.98 (1H, dd, J = 1.1, 7.9 Hz), 7.53 (1H, t, J = 7.4 Hz), 7.40 (2H, t, J = 7.6 Hz), 5.82 (1H, dd, J = 2.0, 5.0 Hz, H-2), 5.42–4.48 (1H, m), 4.19–4.17 (2H, m), 4.11 (1H, dd, J = 7.9, 11.5 Hz, H-6), 3.90 (1H, dd, J = 4.4, 11.6 Hz), 1.08 (63H, s); 13C NMR (100 MHz, CDCl3): δ 190.7 (C), 149.3 (C), 136.5 (C), 132.5 (CH), 130.1 (CH), 127.9 (CH), 107.6 (CH), 81.8 (CH), 69.5 (CH), 65.8 (CH), 61.5 (CH2), 18.1 (Me), 18.0 (Me), 12.5 (CH), 12.3 (CH), 12.0 (CH); HRMS (FAB) m/z: [M + Na]+ cacld for C40H74O5Si3Na, 741.4742; found, 741.4728.

2,6-Anhydro-3-deoxy-1-[4-(methoxycarbonyl)phenyl]-4,5,7-tris-O-[tri(propan-2-yl)silyl]-d-arabino-hept-2-enose (3b)

The reaction was performed with 1a (90 mg, 0.10 mmol), 2b (60 mg, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) to provide 3b (39.7 mg, 57%). [α]D23 = −6.5 (c = 0.7, CHCl3); 1H NMR (400 MHz, CDCl3): δ 8.06 (2H, d, J = 8.6 Hz), 8.01 (2H, d, J = 8.2 Hz), 5.88 (1H, dd, J = 1.4, 5.2 Hz, H-2), 5.42–4.48 (2H, m), 4.19–4.16 (1H, m), 4.11 (1H, dd, J = 8.0, 11.3 Hz, H-6), 3.95 (3H, s), 3.88 (1H, dd, J = 4.3, 11.7 Hz, H-6), 1.08–1.08 (63H, m); 13C NMR (100 MHz, CDCl3): δ 190.2(C), 166.5(C), 148.9 (C), 140.2 (C), 133.2 (C), 129.8 (CH), 129.1 (CH), 108.2 (CH), 81.9 (CH), 69.4 (CH), 65.6 (CH), 61.4 (CH2), 52.4 (Me), 18.1 (Me), 17.9 (Me), 12.4 (CH), 12.3 (CH), 12.0 (CH); HRMS (FAB) m/z: [M + Na]+ cacld for C42H76O7Si3Na, 799.4797; found, 799.4785.

2,6-Anhydro-1-(4-cyanophenyl)-3-deoxy-4,5,7-tris-O-[tri(propan-2-yl)silyl]-d-arabino-hept-2-enose (3c)

The reaction was performed with 1a (90 mg, 0.10 mmol), 2c (50 mg, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) to provide 3c (35.4 mg, 48%) and 4c (15.5 mg, 22%). [α]D23 = −7.1 (c = 0.6, CHCl3); 1H NMR (400 MHz, CDCl3): δ 8.09 (2H, d, J = 8.2 Hz), 7.69 (2H, d, J = 7.7 Hz), 5.95 (1H, dd, J = 1.5, 5.8 Hz, H-2), 5.41–4.48 (1H, m), 4.18–4.16 (1H, m), 4.14–4.11 (2H, m), 3.82 (1H, dd, J = 3.5, 11.7 Hz, H-6), 1.08–1.08 (63H, m); 13C NMR (100 MHz, CDCl3): δ 189.0 (C), 148.4 (C), 139.9 (C), 131.7 (CH), 130.4 (CH), 118.2 (C), 115.7 (C), 108.3 (CH), 82.2 (CH), 69.5 (CH), 65.5 (CH), 61.3 (CH2), 18.1 (Me), 18.0 (Me), 17.9 (Me), 12.4 (CH), 12.3 (CH), 11.9 (CH); HRMS (FAB) m/z: [M + Na]+ cacld for C41H73O5NSi3Na, 766.4694; found, 766.4690.

2,6-Anhydro-3-deoxy-1-(4-methylphenyl)-4,5,7-tris-O-[tri(propan-2-yl)silyl]-d-arabino-hept-2-enose (3d)

The reaction was performed with 1a (90 mg, 0.10 mmol), 2d (40 μL, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) or Pd(PPh3)4 (12 mg, 0.010 mmol) to provide 3d (39.7 mg, 54%; 22.2 mg, 30%). [α]D23 = −9.5 (c = 0.2, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.91 (2H, d, J = 8.2 Hz), 7.20 (2H, d, J = 8.2 Hz), 5.79 (1H, dd, J = 2.7, 4.0 Hz, H-2), 5.41–4.47 (1H, m), 4.19–4.17 (2H, m), 4.10 (1H, dd, J = 8.0 Hz, 11.6, H-6), 3.91 (1H, dd, J = 4.6, 11.6 Hz, H-6), 2.40 (3H, s), 1.08–1.08 (63H, m); 13C NMR (100 MHz, CDCl3): δ 190.4 (C), 149.6 (C), 143.3 (C), 133.9 (C), 130.3 (CH), 128.7 (CH), 106.9 (CH), 81.7 (CH), 69.5 (CH), 65.8 (CH), 61.5 (CH2), 21.7 (Me), 18.2 (Me), 18.1 (Me), 18.0 (Me), 12.5 (CH), 12.3 (CH), 12.0 (CH); HRMS (FAB) m/z: [M + Na]+ cacld. for C41H76O5Si3Na, 755.4898; found, 755.4896.

1,5-Anhydro-2-deoxy-1-phenyl-3,4,6-tris-O-[tri(propan-2-yl)silyl]-d-arabino-hex-1-enitol (4a)

The reaction was performed with 1a (90 mg, 0.10 mmol), 2a (35 μL, 0.30 mmol), and Pd(PPh3)4 (12 mg, 0.010 mmol) to provide 4a (46.5 mg, 67%). The spectral characteristics were in agreement with the previously reported data.[12] [α]D23 = −11.4 (c = 0.3, CH2Cl2); 1H NMR (400 MHz, CDCl3): δ 7.65–7.61 (2H, m), 7.49–7.27 (3H, m), 5.35 (1H, dd, J = 1.2, 5.7 Hz, H-2), 4.46 (1H, dt, J = 2.1, 7.8 Hz), 4.19–4.14 (1H, m), 4.13 (1H, m), 4.11 (1H, dd, J = 7.8, 11.3 Hz, H-6), 3.90 (1H, dd, J = 4.3, 11.1 Hz), 1.08–1.08 (63H, m); 13C NMR (100 MHz, CDCl3): δ 150.3 (C), 136.3 (C), 128.2 (CH), 127.9 (CH), 125.4 (CH), 96.7 (CH), 81.3 (CH), 70.1 (CH), 66.8 (CH), 62.0 (CH2), 18.2 (Me), 18.1 (Me), 18.0 (Me), 12.6 (CH), 12.5 (CH), 12.1 (CH); HRMS (FAB) m/z: [M + K]+ cacld for C39H74O4Si3K, 729.4532; found, 729.4521.

1,5-Anhydro-2-deoxy-1-[4-(methoxycarbonyl)phenyl]-3,4,6-tris-O-[tri(propan-2-yl)silyl]-d-arabino-hex-1-enitol (4b)

The reaction was performed with 1a (90 mg, 0.10 mmol), 2b (60 mg, 0.30 mmol), and Pd(PPh3)4 (12 mg, 0.010 mmol) to provide 4b (53.2 mg, 71%). [α]D23 = −6.8 (c = 1.1, CHCl3); 1H NMR (400 MHz, CDCl3): δ 8.00 (2H, d, J = 8.6 Hz), 7.70 (2H, d, J = 8.4 Hz), 5.47 (1H, dd, J = 1.3, 5.2 Hz, H-2), 4.50–4.48 (1H, m), 4.19–4.17 (1H, m), 4.15–4.10 (2H, m), 3.92 (3H, s), 3.86 (1H, dd, J = 3.7, 11.2 Hz, H-6), 1.08–1.08 (63H, m); 13C NMR (100 MHz, CDCl3): δ 167.0 (C), 149.3 (C), 140.6 (C), 129.7 (C), 129.4 (CH), 125.2 (CH), 98.7 (CH), 81.5 (CH), 70.0 (CH), 66.5 (CH), 61.9 (CH2), 52.1 (Me), 18.2 (Me), 18.1 (Me), 18.0 (Me), 12.6 (CH), 12.4 (CH), 12.0 (CH); HRMS (FAB) m/z: [M + H]+ cacld for C41H77O6Si3, 749.5028; found, 749.5012.

1,5-Anhydro-1-(4-cyanophenyl)-2-deoxy-3,4,6-tris-O-[tri(propan-2-yl)silyl]-d-arabino-hex-1-enitol (4c)

The reaction was performed with 1a (90 mg, 0.10 mmol), 2c (50 mg, 0.30 mmol), and Pd(PPh3)4 (12 mg, 0.010 mmol) to provide 4c (39.9 mg, 56%). The spectral characteristics were in agreement with the previously reported data.[6j] [α]D23 = −9.5 (c = 1.0, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.61 (2H, d, J = 8.4 Hz), 7.03 (2H, d, J = 8.5 Hz), 5.48 (1H, dd, J = 1.0, 5.0 Hz, H-2), 4.51–4.47 (1H, m), 4.18–4.16 (1H, m), 4.14–4.09 (2H, m), 3.84 (1H, dd, J = 3.7, 11.6 Hz, H-6), 1.08–1.08 (63H, m); 13C NMR (100 MHz, CDCl3): δ 148.5 (C), 140.5 (C), 131.9 (CH), 125.7 (CH), 119.0 (C), 111.6 (C), 99.5 (CH), 81.7 (CH), 69.9 (CH), 66.3 (CH), 61.7 (CH2), 18.1 (Me), 18.0 (Me), 12.5 (CH), 12.4 (CH), 12.0 (CH); HRMS (FAB) m/z: [M + H]+ cacld for C40H74O4NSi3, 716.4926; found, 716.4925.

2,6-Anhydro-3-deoxy-1-phenyl-4,5,7-tris-O-[tri(propan-2-yl)silyl]-d-lyxo-hept-2-enose (5a)

The reaction was performed with 1b (90 mg, 0.10 mmol), 2a (35 μL, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) to provide 5a (58.7 mg, 82%). [α]D23 = −32.6 (c = 3.2, CHCl3); 1H NMR (400 MHz, CDCl3): δ 8.10–7.82 (2H, m), 7.53 (1H, t, J = 7.3 Hz), 7.40 (2H, t, J = 7.8 Hz), 6.00–5.41 (1H, m), 4.67–3.75 (5H, m), 1.12–1.01 (63H, m); 13C NMR (100 MHz, CDCl3): δ 190.3 (C), 149.6 (C), 136.5 (C), 132.6 (CH), 130.0 (CH), 128.0 (CH), 110.1 (CH), 81.4 (CH), 70.1 (CH), 64.2 (CH), 60.4 (CH2), 18.9 (Me), 18.0 (Me), 12.6 (CH), 12.0 (CH); HRMS (FAB) m/z: [M – H]− cacld for C40H73O5Si3, 717.4766; found, 717.4757.

2,6-Anhydro-3-deoxy-1-[4-(methoxycarbonyl)phenyl]-4,5,7-tris-O-[tri(propan-2-yl)silyl]-d-lyxo-hept-2-enose (5b)

The reaction was performed with 1b (90 mg, 0.10 mmol), 2b (60 mg, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) to provide 5b (49.8 mg, 74%). [α]D23 = −35.0 (c = 0.2, CHCl3); 1H NMR (400 MHz, CDCl3): δ 8.06 (2H, d, J = 8.2 Hz), 8.11–7.97 (2H, m), 5.90–5.60 (1H, m), 5.72–3.98 (5H, m), 3.95 (3H, s), 1.12–1.01 (63H, m), 13C NMR (100 MHz, CDCl3): δ 189.7 (C), 166.4 (C), 149.3 (C), 140.3 (C), 133.3 (C), 129.7 (CH), 129.2 (CH), 110.9 (CH), 81.4 (CH), 70.0 (CH), 64.3 (CH), 61.0 (CH2), 52.4 (Me), 18.2 (Me), 18.0 (Me), 12.6 (CH), 12.0 (CH); HRMS (FAB) m/z: M+• cacld for C42H76O7Si3, 776.4899; found, 776.4905.

2,6-Anhydro-1-(4-cyanophenyl)-3-deoxy-4,5,7-tris-O-[tri(propan-2-yl)silyl]-d-lyxo-hept-2-enose (5c)

The reaction was performed with 1b (90 mg, 0.10 mmol), 2c (50 mg, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) to provide 5c (46.1 mg, 62%). [α]D23 = −30.7 (c = 1.7, CHCl3); 1H NMR (400 MHz, CDCl3): δ 8.23–7.91 (2H, m), 7.69 (2H, d, J = 8.4 Hz), 6.19–5.41 (1H, m), 4.85–3.63 (5H, m), 1.12–1.01 (63H, m); 13C NMR (100 MHz, CDCl3): δ 188.6 (C), 148.5 (C), 139.8 (C), 131.8 (CH), 130.4 (CH), 118.2 (C), 115.8 (C), 111.5 (CH), 80.8 (CH), 70.1 (CH), 64.2 (CH), 60.2 (CH2), 18.3 (Me), 18.2 (Me), 18.0 (Me), 12.6 (CH), 12.0 (CH); HRMS (FAB) m/z: M+• cacld for C41H73O5NSi3, 743.4797; found, 743.4790.

2,6-Anhydro-3-deoxy-1-(4-methylphenyl)-4,5,7-tris-O-[tri(propan-2-yl)silyl]-d-lyxo-hept-2-enose (5d)

The reaction was performed with 1b (90 mg, 0.10 mmol), 2d (40 μL, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) to provide 5d (64.2 mg, 88%). [α]D23 = −35.7 (c = 1.1, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.99–7.82 (2H, m), 7.20 (2H, d, J = 8.0 Hz), 5.95–5.35 (1H, m), 4.85–3.65 (5H, m), 2.40 (3H, s), 1.11–1.03 (63H, m); 13C NMR (100 MHz, CDCl3): δ 189.9 (C), 150.0 (C), 143.5 (C), 133.8 (C), 130.2 (CH), 128.7 (CH), 109.7 (CH), 81.3 (CH), 70.0 (CH), 64.4 (CH), 60.5 (CH2), 21.7 (Me), 18.2 (Me), 18.0 (Me), 12.6 (CH), 12.0 (CH); HRMS (FAB) m/z: M+• cacld for C41H76O5Si3, 732.5001; found, 732.5006.

1,5-Anhydro-2-deoxy-1-phenyl-3,4,6-tris-O-[tri(propan-2-yl)silyl]-d-lyxo-hex-1-enitol (6a)

The reaction was performed with 1b (90 mg, 0.10 mmol), 2a (35 μL, 0.30 mmol), and Pd(PPh3)4 (12 mg, 0.010 mmol) to provide 6a (34.2 mg, 50%) and 5a (17.9 mg, 25%). Compound 6a was isolated with an inseparable impurity. [α]D23 = −23.3 (c = 1.7, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.62–7.59 (2H, m), 7.33–7.28 (3H, m), 5.39–5.26 (1H, m), 4.52–4.35 (2H, m), 4.31 (1H, t, J = 4.0 Hz), 4.28–4.10 (2H, m), 1.11–1.00 (63H, m); 13C NMR (100 MHz, CDCl3): δ 150.3 (C), 135.4 (C), 128.5 (CH), 128.0 (CH), 125.4 (CH), 98.7 (CH), 80.9 (CH), 76.7 (CH), 70.2 (CH), 70.0 (CH2), 18.3 (Me), 18.0 (Me), 12.7 (CH), 12.1 (CH); HRMS (FAB) m/z: [M – H]− cacld for C39H73O4Si3, 689.4817; found, 689.4797.

1,5-Anhydro-1-(4-cyanophenyl)-2-deoxy-3,4,6-tris-O-[tri(propan-2-yl)silyl]-d-lyxo-hex-1-enitol (6c)

The reaction was performed with 1b (90 mg, 0.10 mmol), 2c (50 mg, 0.30 mmol), and Pd(PPh3)4 (12 mg, 0.010 mmol) to provide 6c (11.1 mg, 16%) and 5c (34.1 mg, 46%). Compound 6c was isolated with an inseparable impurity. [α]D23 = −22.1 (c = 0.4, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.69 (2H, d, J = 8.5 Hz), 7.60 (2H, d, J = 8.3 Hz), 5.54–5.37 (1H, m), 4.55–4.34 (2H, m), 4.31 (1H, d, J = 3.7 Hz), 4.26–4.08 (2H, m), 1.10–1.03 (63H, m); 13C NMR (100 MHz, CDCl3): δ 148.6 (C), 139.6 (C), 133.9 (CH), 125.7 (CH), 118.9 (C), 112.0 (C), 101.8 (CH), 80.9 (CH), 70.0 (CH), 60.9 (CH), 60.8 (CH2), 18.2 (Me), 17.9 (Me), 12.7 (CH), 12.0 (CH); HRMS (FAB) m/z: [M + H]+ cacld for C40H74O4NSi3, 716.4926; found, 716.4935.

1,5-Anhydro-2-deoxy-1-(4-methylphenyl)-3,4,6-tris-O-[tri(propan-2-yl)silyl]-d-lyxo-hex-1-enitol (6d)

The reaction was performed with 1b (90 mg, 0.10 mmol), 2d (40 μL, 0.30 mmol), and Pd(PPh3)4 (12 mg, 0.010 mmol) to provide 6d (21.2 mg, 30%) and 5d (19.8 mg, 27%). Compound 6d was isolated with an inseparable impurity. [α]D23 = −27.2 (c = 1.0, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.49 (2H, d, J = 8.1 Hz), 7.11 (2H, d, J = 8.1 Hz), 5.39–5.20 (1H, m), 4.50–4.34 (2H, m), 4.33–4.28 (1H, m), 4.28–4.18 (1H, m), 4.15–4.12 (1H, m), 2.34 (3H, s), 1.11–1.00 (63H, m); 13C NMR (100 MHz, CDCl3): δ 150.3 (C), 142.8 (C), 132.6 (C), 128.7 (CH), 128.0 (CH), 98.7 (CH), 81.0 (CH), 70.2 (CH), 65.2 (CH), 61.0 (CH2), 21.2 (Me), 18.3 (Me), 18.2 (Me), 18.0 (Me), 12.7 (CH), 12.1 (CH); HRMS (FAB) m/z: [M + H]+ cacld for C40H77O4Si3, 705.5130; found, 705.5094.

2,6-Anhydro-3,7-dideoxy-1-phenyl-4,5-bis-O-[tri(propan-2-yl)silyl]-l-arabino-hept-2-enose (7a)

The reaction was performed with 1c (73 mg, 0.10 mmol), 2a (35 μL, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) to provide 7a (40.8 mg, 75%). [α]D23 = 39.7 (c = 0.7, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.89 (2H, dd, J = 1.1, 7.9 Hz), 7.54 (1H, t, J = 7.7 Hz), 7.42 (2H, t, J = 7.9 Hz), 5.76 (1H, dd, J = 1.4, 5.1 Hz, H-2), 4.56 (1H, tq, J = 1.8, 6.9 Hz, H-5), 4.23 (1H, dt, J = 2.1, 5.2 Hz, H-3), 4.01 (1H, dd, J = 2.0, 3.7 Hz, H-4), 1.45 (3H, d, J = 6.8 Hz), 1.07–1.07 (42H, m); 13C NMR (100 MHz, CDCl3): δ 191.5 (C), 148.7 (C), 136.8 (C), 132.5 (CH), 129.8 (CH), 128.0 (CH), 108.6 (CH), 75.8 (CH), 72.7 (CH), 66.5 (CH), 18.1 (Me), 15.7 (Me), 12.5 (CH), 12.4 (CH); HRMS (FAB) m/z: [M + Na]+ cacld for C31H54O4Si2Na, 569.3458; found, 569.3488.

2,6-Anhydro-3,7-dideoxy-1-[4-(methoxycarbonyl)phenyl]-4,5-bis-O-[tri(propan-2-yl)silyl]-l-arabino-hept-2-enose (7b)

The reaction was performed with 1c (73 mg, 0.10 mmol), 2b (60 mg, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) to provide 7b (45.6 mg, 76%). [α]D23 = 35.9 (c = 0.4, CHCl3); 1H NMR (400 MHz, CDCl3): δ 8.08 (2H, d, J = 8.5 Hz), 7.92 (2H, d, J = 8.3 Hz), 5.80 (1H, dd, J = 1.4, 5.2 Hz, H-2), 4.56 (1H, tq, J = 1.4, 7.1 Hz, H-5), 4.23 (1H, dt, J = 2.1, 5.2 Hz, H-3), 4.02 (1H, dd, J = 2.0, 3.6 Hz, H-4), 3.95 (3H, s), 1.44 (3H, d, J = 7.2 Hz), 1.07–1.07 (42H, m); 13C NMR (100 MHz, CDCl3): δ 190.9 (C), 166.4 (C), 148.3 (C), 140.4 (C), 133.2 (C), 129.6 (CH), 129.2 (CH), 109.4 (CH), 75.9 (CH), 72.5 (CH), 66.4 (CH), 52.4 (Me), 18.1 (Me), 15.6 (Me), 12.5 (CH), 12.4 (CH); HRMS (FAB) m/z: Found [M + Na]+ cacld for C33H56O6Si2Na, 627.3513; found, 627.3506.

2,6-Anhydro-1-(4-cyanophenyl)-3,7-dideoxy-4,5-bis-O-[tri(propan-2-yl)silyl]-l-arabino-hept-2-enose (7c)

The reaction was performed with 1c (73 mg, 0.10 mmol), 2c (50 mg, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) to provide 7c (28.1 mg, 49%) and 8c (4.4 mg, 8%). [α]D23 = 56.3 (c = 1.5, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.97 (2H, d, J = 8.5 Hz), 7.71 (2H, d, J = 8.5 Hz), 5.84 (1H, dd, J = 1.4, 5.2 Hz, H-2), 4.55 (1H, tq, J = 1.9, 7.1 Hz, H-5), 4.23 (1H, dt, J = 1.7, 5.6 Hz, H-3), 4.02 (1H, d, J = 1.8 Hz, H-4), 1.43 (3H, d, J = 7.2 Hz), 1.08–1.08 (42H, m); 13C NMR (100 MHz, CDCl3): δ 189.8 (C), 148.1 (C), 140.2 (C), 131.8 (CH), 130.1 (CH), 118.1 (C), 115.7 (C), 109.2 (CH), 76.1 (CH), 72.4 (CH), 66.2 (CH), 18.1 (Me), 18.0 (Me), 15.6 (Me), 12.5 (CH), 12.4 (CH); HRMS (FAB) m/z: [M + H]+ cacld for C32H54O4NSi2, 572.3591; found, 72.3588.

2,6-Anhydro-3,7-dideoxy-1-(4-methylphenyl)-4,5-bis-O-[tri(propan-2-yl)silyl]-l-arabino-hept-2-enose (7d)

The reaction was performed with 1c (73 mg, 0.10 mmol), 2d (40 μL, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) or Pd(PPh3)4 (12 mg, 0.010 mmol) to provide 7d (45.3 mg, 81%; 21.9 mg, 39%, respectively). [α]D23 = 38.8 (c = 1.4, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.82 (2H, d, J = 8.1 Hz), 7.22 (2H, d, J = 8.0 Hz), 5.74 (1H, dd, J = 1.4, 5.2 Hz, H-2), 4.55 (1H, tq, J = 1.9, 7.2 Hz, H-5), 4.23 (1H, dt, J = 2.1, 4.5 Hz, H-3), 4.01 (1H, dd, J = 2.0, 3.7 Hz, H-4), 2.41 (3H, s), 1.44 (3H, d, J = 7.1 Hz), 1.09–1.07 (42H, m); 13C NMR (100 MHz, CDCl3): δ 191.1 (C), 148.9 (C), 143.3 (C), 134.0 (C), 130.0 (CH), 128.7 (CH), 107.8 (CH), 75.8 (CH), 72.7 (CH), 66.5 (CH), 21.7 (Me), 18.1 (Me), 15.7 (Me), 12.5 (CH), 12.4 (CH); HRMS (FAB) m/z: [M + H]+ cacld for C32H57O4Si2, 561.3795; found, 561.3768.

1,5-Anhydro-2,6-dideoxy-1-phenyl-3,4-bis-O-[tri(propan-2-yl)silyl]-l-arabino-hex-1-enitol (8a)

The reaction was performed with 1c (73 mg, 0.10 mmol), 2a (35 μL, 0.30 mmol), and Pd(PPh3)4 (12 mg, 0.010 mmol) to provide 8a (18.4 mg, 36%) and 7a (6.7 mg, 12%). Compound 8a was isolated with an inseparable impurity. [α]D23 = 28.3 (c = 0.8, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.60 (2H, d, J = 6.7 Hz), 7.34–7.29 (3H, m), 5.36 (1H, dd, J = 1.2, 5.1 Hz, H-2), 4.49 (1H, tq, J = 2.0, 7.1 Hz, H-5), 4.25–4.21 (1H, m, H-3), 3.99 (1H, d, J = 1.5 Hz, H-4), 1.44 (3H, d, J = 7.2 Hz), 1.06–1.06 (42H, m); 13C NMR (100 MHz, CDCl3): δ 149.7 (C), 136.6 (C), 128.1 (CH), 128.0 (CH), 125.3 (CH), 97.0 (CH), 75.2 (CH), 73.3 (CH), 67.6 (CH), 18.2 (Me), 18.0 (Me), 16.1 (Me), 12.6 (CH), 12.3 (CH); HRMS (FAB) m/z: [M + H]+ cacld for C30H55O3Si2, 519.3690; found, 519.3655.

1,5-Anhydro-2,6-dideoxy-1-[4-(methoxycarbonyl)phenyl]-3,4-bis-O-[tri(propan-2-yl)silyl]-l-arabino-hex-1-enitol (8b)

The reaction was performed with 1c (73 mg, 0.10 mmol), 2b (60 mg, 0.30 mmol), and Pd(PPh3)4 (12 mg, 0.010 mmol) to provide 8b (19.7 mg, 34%). [α]D23 = 29.3 (c = 1.0, CHCl3); 1H NMR (400 MHz, CDCl3): δ 8.00 (2H, d, J = 8.6 Hz), 7.66 (2H, d, J = 8.3 Hz), 5.48 (1H, dd, J = 1.3, 5.1 Hz, H-2), 4.51 (1H, tq, J = 2.0, 7.0 Hz, H-5), 4.24 (1H, dt, J = 2.0, 5.2 Hz, H-3), 4.01 (1H, d, J = 1.5 Hz, H-4), 3.91 (3H, s), 1.44 (3H, d, J = 7.2 Hz), 1.07 (42H, s); 13C NMR (100 MHz, CDCl3): δ 166.9 (C), 148.8 (C), 140.8 (C), 129.6 (C), 129.5 (CH), 125.0 (CH), 98.9 (CH), 75.4 (CH), 73.1 (CH), 67.3 (CH), 52.1 (Me), 18.2 (Me), 18.1 (Me), 16.0 (Me), 12.6 (CH), 12.5 (CH); HRMS (FAB) m/z: [M + H]+ cacld for C32H57O5Si2, 577.3745; found, 577.3759.

1,5-Anhydro-1-(4-cyanophenyl)-2,6-dideoxy-3,4-bis-O-[tri(propan-2-yl)silyl]-l-arabino-hex-1-enitol (8c)

The reaction was performed with 1c (73 mg, 0.10 mmol), 2c (50 mg, 0.30 mmol), and Pd(PPh3)4 (12 mg, 0.010 mmol) to provide 8c (17.4 mg, 32%) and 7c (2.1 mg, 4%). A small amount of the adduct 8c decomposed after several days, as confirmed by the 1H NMR spectra (see the Supporting Information). [α]D23 = 44.2 (c = 0.3, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.70 (2H, d, J = 8.5 Hz), 7.62 (2H, d, J = 8.4 Hz), 5.49 (1H, d, J = 4.7 Hz, H-2), 4.52 (1H, tq, J = 1.6, 7.0 Hz, H-5), 4.23 (1H, dt, J = 2.1, 5.2 Hz, H-3), 4.01 (1H, d, J = 1.7 Hz, H-4), 1.43 (3H, d, J = 7.0 Hz), 1.09–1.09 (42H, m); 13C NMR (100 MHz, CDCl3): δ 148.0 (C), 140.7 (C), 132.0 (CH), 125.6 (CH), 119.0 (C), 111.5 (C), 99.7 (CH), 75.5 (CH), 72.9 (CH), 67.1 (CH), 18.1 (Me), 18.0 (Me), 15.9 (Me), 12.5 (CH); HRMS (FAB) m/z: [M + H]+ cacld for C31H54O3NSi2, 544.3642; found, 544.3647.

2,6-Anhydro-3,7-dideoxy-1-phenyl-4,5-bis-O-[tri(propan-2-yl)silyl]-l-lyxo-hept-2-enose (9a)

The reaction was performed with 1d (73 mg, 0.10 mmol), 2a (35 μL, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) to provide 9a (45.7 mg, 84%). A small amount of the adduct 9a was decomposed after several days, as confirmed by the 1H NMR spectra (see the Supporting Information). [α]D23 = 64.0 (c = 0.7, CHCl3); 1H NMR (400 MHz, CDCl3): δ (400 MHz) 7.87 (2H, d, J = 7.1 Hz), 7.53 (1H, t, J = 7.3 Hz), 7.41 (2H, t, J = 7.5 Hz), 5.61 (1H, m), 4.62 (1H, m), 4.53 (1H, m), 4.09 (1H, m), 1.51 (3H, d, J = 6.6 Hz), 1.13–1.07 (42H, m); 13C NMR (100 MHz, CDCl3): δ 190.9 (C), 149.7 (C), 136.7 (C), 132.5 (CH), 129.7 (CH), 128.0 (CH), 112.8 (CH), 75.1 (CH), 70.3 (CH), 63.8 (CH), 18.4 (Me), 18.1 (Me), 14.1 (Me), 13.2 (CH), 12.6 (CH); HRMS (FAB) m/z: [M + Na]+ cacld for C31H54O4Si2Na, 569.3458; found, 569.3469.

2,6-Anhydro-3,7-dideoxy-1-[4-(methoxycarbonyl)phenyl]-4,5-bis-O-[tri(propan-2-yl)silyl]-l-lyxo-hept-2-enose (9b)

The reaction was performed with 1d (73 mg, 0.10 mmol), 2b (60 mg, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) to provide 9b (53.9 mg, 90%). [α]D23 = 70.9 (c = 1.4, CHCl3); 1H NMR (400 MHz, CDCl3): δ 8.07 (2H, d, J = 8.3 Hz), 7.89 (2H, d, J = 8.5 Hz), 5.63 (1H, m), 4.64 (1H, m), 4.33 (1H, m), 4.13 (1H, m), 4.09 (3H, s), 1.49 (3H, d, J = 6.6 Hz), 1.13–1.07 (42H, m); 13C NMR (100 MHz, CDCl3): δ 190.2 (C), 166.4 (C), 149.6 (C), 140.5 (C), 133.2 (C), 129.5 (CH), 129.2 (CH), 113.9 (CH), 75.3 (CH), 70.2 (CH), 67.7 (CH), 52.4 (Me), 18.4 (Me), 18.3 (Me), 18.2 (Me), 18.1 (Me), 14.1 (Me), 13.3 (CH), 12.6 (CH); HRMS (FAB) m/z: [M + Na]+ cacld for C33H56O6Si2Na, 627.3513; found, 627.3486.

2,6-Anhydro-1-(4-cyanophenyl)-3,7-dideoxy-4,5-bis-O-[tri(propan-2-yl)silyl]-l-lyxo-hept-2-enose (9c)

The reaction was performed with 1d (73 mg, 0.10 mmol), 2c (50 mg, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) to provide 9c (32.4 mg, 57%). [α]D23 = 68.3 (c = 1.0, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.95 (2H, d, J = 8.5 Hz), 7.71 (2H, d, J = 8.4 Hz), 5.64 (1H, m), 4.65 (1H, m), 4.30 (1H, m), 4.08 (1H, m), 1.48 (3H, d, J = 6.6 Hz), 1.13–1.07 (42H, m); 13C NMR (100 MHz, CDCl3): δ 189.0 (C), 149.5 (C), 140.2 (C), 131.8 (CH), 130.0 (CH), 118.1 (C), 115.7 (C), 113.9 (CH), 75.4 (CH), 70.1 (CH), 68.0 (CH), 18.3 (Me), 18.2 (Me), 16.1 (Me), 13.4 (CH), 12.6 (CH); HRMS (FAB) m/z: [M + H]+ cacld for C32H54O4NSi2, 572.3591; found, 572.3622.

2,6-Anhydro-3,7-dideoxy-1-(4-methylphenyl)-4,5-bis-O-[tri(propan-2-yl)silyl]-l-lyxo-hept-2-enose (9d)

The reaction was performed with 1d (73 mg, 0.10 mmol), 2d (40 μL, 0.30 mmol), and Pd(OAc)2 (2.0 mg, 0.010 mmol) or Pd(PPh3)4 (12 mg, 0.010 mmol) to provide 9d (50.8 mg, 91%, 31.1 mg; 55%, respectively). [α]D23 = 79.2 (c = 1.8, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.81 (2H, d, J = 8.2 Hz), 7.21 (2H, d, J = 8.1 Hz), 5.59 (1H, m), 4.62 (1H, m), 4.34 (1H, m), 4.09 (1H, m), 2.41 (3H, s), 1.51 (3H, d, J = 6.6 Hz), 1.23–1.08 (42H, m); 13C NMR (100 MHz, CDCl3): δ 190.5 (C), 149.9 (C), 143.4 (C), 133.9 (C), 130.0 (CH), 128.7 (CH), 111.7 (CH), 75.0 (CH), 70.3 (CH), 67.5 (CH), 21.7 (Me), 18.4 (Me), 18.2 (Me), 15.7 (Me), 13.2 (CH), 12.7 (CH); HRMS (FAB) m/z: M+• cacld for C32H56O4Si2, 560.3717; found, 560.3696.

1,5-Anhydro-2,6-dideoxy-1-phenyl-3,4-bis-O-[tri(propan-2-yl)silyl]-l-lyxo-hex-1-enitol (10a)

The reaction was performed with 1d (73 mg, 0.10 mmol), 2a (35 μL, 0.30 mmol), and Pd(PPh3)4 (12 mg, 0.010 mmol) to provide 10a (25.6 mg, 49%) and 9a (20.8 mg, 38%). A small amount of the adduct 10a was decomposed after several days, as confirmed by the 1H NMR spectra (see the Supporting Information). [α]D23 = 57.4 (c = 0.8, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.56 (2H, dd, J = 1.5, 8.1 Hz), 7.35–7.28 (3H, m), 5.28 (1H, d, J = 4.23 Hz), 4.56 (1H, t, J = 3.5 Hz), 4.40–4.38 (1H, m), 4.15 (1H, t, J = 3.7 Hz), 1.50 (3H, d, J = 6.7 Hz), 1.13–1.07 (42H, m); 13C NMR (100 MHz, CDCl3): δ 150.2 (C), 135.8 (C), 128.3 (CH), 128.1 (CH), 125.2 (CH), 98.8 (CH), 74.2 (CH), 70.7 (CH), 66.6 (CH), 18.3 (Me), 18.2 (Me), 14.9 (Me), 12.9 (CH), 12.8 (CH); HRMS (FAB) m/z: [M + Na]+ cacld for C30H54O3Si2Na, 541.3509; found, 541.3499.

1,5-Anhydro-2,6-dideoxy-1-[4-(methoxycarbonyl)phenyl]-3,4-bis-O-[tri(propan-2-yl)silyl]-l-lyxo-hex-1-enitol (10b)

The reaction was performed with 1d (73 mg, 0.10 mmol), 2b (60 mg, 0.30 mmol), and Pd(PPh3)4 (12 mg, 0.010 mmol) to provide 10b (12.0 mg, 21%) and 9b (26.5 mg, 44%). [α]D23 = 57.3 (c = 0.4, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.99 (2H, d, J = 8.6 Hz), 7.62 (2H, d, J = 8.5 Hz), 5.38 (1H, d, J = 3.6 Hz), 4.58 (1H, m), 4.39 (1H, m), 4.14 (1H, t, J = 3.6 Hz), 3.91 (3H, s), 1.50 (3H, d, J = 6.7 Hz), 1.13–1.07 (42H, m); 13C NMR (100 MHz, CDCl3): δ 166.9 (C), 149.4 (C), 140.0 (C), 129.6 (C), 129.5 (CH), 124.9 (CH), 100.9 (CH), 74.4 (CH), 70.6 (CH), 66.9 (CH), 52.1 (Me), 18.3 (Me), 18.2 (Me), 13.0 (Me), 12.8 (CH); HRMS (FAB) m/z: [M + H]+ cacld for C32H57O5Si2, 577.3745; found, 577.3741.

1,5-Anhydro-1-(4-cyanophenyl)-2,6-dideoxy-3,4-bis-O-[tri(propan-2-yl)silyl]-l-lyxo-hex-1-enitol (10c)

The reaction was performed with 1d (73 mg, 0.10 mmol), 2c (50 mg, 0.30 mmol), and Pd(PPh3)4 (12 mg, 0.010 mmol) to provide 10c (10.0 mg, 19%) and 9c (33.0 mg, 58%). [α]D23 = 74.0 (c = 0.4, CHCl3); 1H NMR (400 MHz, CDCl3): δ 7.65(2H, d, J = 9.5 Hz), 7.61 (2H, d, J = 8.5 Hz), 5.37 (1H, m), 4.59 (1H, m), 4.37 (1H, m), 4.12 (1H, t, J = 3.3 Hz), 1.49 (3H, d, J = 6.8 Hz), 1.11–1.08 (42H, m); 13C NMR (100 MHz, CDCl3): δ 148.7 (C), 139.9 (C), 132.0 (CH), 125.5 (CH), 118.9 (C), 111.5 (C), 101.9 (CH), 74.5 (CH), 70.5 (CH), 66.9 (CH), 18.3 (Me), 18.2 (Me), 15.4 (Me), 13.1 (CH), 12.8 (CH); HRMS (FAB) m/z: [M + H]+ cacld for C31H54O3NSi2, 544.3642; found, = 544.3614.