[4+1]Annulation of in situ generated azoalkenes with amines:A powerful approach to access 1-substituted 1,2,3-triazoles  

作　　者：Hongwei Wang Yongquan Ning Paramasivam Sivaguru Giuseppe Zanoni Xihe Bi 

机构地区：[1]Department of Chemistry,Northeast Normal University,Changchun 130024,China [2]Department of Chemistry,University of Pavia,Viale Taramelli 12,Pavia 27100,Italy [3]State Key Laboratory of Elemento-Organic Chemistry,Nankai University,Tianjin 300071,China

出　　处：《Chinese Chemical Letters》2022年第3期1550-1554,共5页中国化学快报（英文版）

基　　金：supported by the National Natural Science Foundation of China(NSFC,Nos.21871043,21961130376);Department of Science and Technology of Jilin Province(Nos.20180101185JC,20190701012GH,20200801065GH);the Fundamental Research Funds for the Central Universities(Nos.2412019ZD001,2412020ZD003)。

摘　　要：1-Substituted 1,2,3-triazoles represents‘privileged’structural scaffolds of many clinical pharmaceuticals.However,the traditional methods for their preparation mainly rely on thermal[3+2]cycloaddition of potentially dangerous acetylene and azides.Here we report a base-mediated[4+1]annulation of azoalkenes generated in situ from readily available difluoroacetaldehyde N-tosylhydrazones(DFHZ-Ts)with amines under relatively mild conditions.This azide-and acetylene-free strategy provides facile access to diverse 1-substituted 1,2,3-triazole derivatives in high yield in a regiospecific manner.This transformation has great functional group tolerance and can suit a broad substrate scope.Furthermore,the application of this novel methodology in the gram-scale synthesis of an antibiotic drug PH-027 and in the late-stage derivatization of several bioactive small molecules and clinical drugs demonstrated its generality,practicability and applicability.

关 键 词：[4+1]Annulation Azoalkene Late-stage functionalization 1-Substituted 1 2 3-triazoles 

分 类 号：O626.26[理学—有机化学] TQ460.1[理学—化学]