Hao Wang1, Hoimin Jung2,3, Fangfang Song1, Shiyang Zhu1, Ziqian Bai1, Danye Chen1, Gang He1, Sukbok Chang4,5, Gong Chen6. 1. State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, China. 2. Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea. 3. Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, Republic of Korea. 4. Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea. sbchang@kaist.ac.kr. 5. Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, Republic of Korea. sbchang@kaist.ac.kr. 6. State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, China. gongchen@nankai.edu.cn.
Abstract
N-N linkages are found in many natural compounds and endow fascinating structural and functional properties. In comparison to the myriad methods for the construction of C-N bonds, chemistry for N-N coupling, especially in an intermolecular fashion, remains underdeveloped. Here, we report a nitrene-mediated intermolecular N-N coupling of dioxazolones and arylamines under iridium or iron catalysis. These reactions offer a simple and efficient method for the synthesis of various hydrazides from readily available carboxylic acid and amine precursors. Although the Ir-catalysed conditions usually give higher N-N coupling yield than the Fe-catalysed conditions, the reactions of sterically more demanding dioxazolones derived from α-substituted carboxylic acids work much better under the Fe-catalysed conditions. Mechanistic studies revealed that the nitrogen atom of Ir acyl nitrene intermediates has strong electrophilicity and can undergo nucleophilic attack with arylamines with the assistance of Cl···HN hydrogen bonding to form the N-N bond with high efficiency and chemoselectivity.
N-N linkages are found in many natural compounds and endow fascinating structural and functional properties. In comparison to the myriad methods for the construction of C-N bonds, chemistry for N-N coupling, especially in an intermolecular fashion, remains underdeveloped. Here, we report a nitrene-mediated intermolecular N-N coupling of n class="Chemical">dioxazolones and arylamines under iridium or iron catalysis. These reactions offer a simple and efficient method for the synthesis of various hydrazides from readily available carboxylic acid and amine precursors. Although the Ir-catalysed conditions usually give higher N-N coupling yield than the Fe-catalysed conditions, the reactions of sterically more demanding dioxazolones derived from α-substituted carboxylic acids work much better under the Fe-catalysed conditions. Mechanistic studies revealed that the nitrogen atom of Ir acyl nitrene intermediates has strong electrophilicity and can undergo nucleophilic attack with arylamines with the assistance of Cl···HN hydrogen bonding to form the N-N bond with high efficiency and chemoselectivity.
Authors: Lourdes Maestre; Ruth Dorel; Óscar Pablo; Imma Escofet; W M C Sameera; Eleuterio Álvarez; Feliu Maseras; M Mar Díaz-Requejo; Antonio M Echavarren; Pedro J Pérez Journal: J Am Chem Soc Date: 2017-02-06 Impact factor: 15.419