Photocatalyzed[2+1]cyclization of alkenes and silylated trifluorodiazoethanes:facile entry into(difluoromethylene)cyclopropanes  

作　　者：Suo Chen Yizhi Zhang Shanshan Liu Xiao Shen 

机构地区：[1]The Institute for Advanced Studies,Engineering Research Center of Organosilicon Compounds&Materials,Ministry of Education,Wuhan University,Wuhan 430072,China [2]Shenzhen Research Institute of Wuhan University,Shenzhen 518057,China

出　　处：《Science China Chemistry》2023年第11期3141-3147,共7页中国科学（化学英文版）

基　　金：supported by the National Key Research and Development Program of China(2022YFA1506100);Shenzhen Science and Technology Program(JCYJ20220818100604009);Guangdong Basic and Applied Basic Research Foundation(2021A1515010105,2023A1515010601)。

摘　　要：Methylenecyclopropanes are among the most robust building blocks in synthetic chemistry,but the study on(difluoromethylene)-cyclopropanes is rather limited,because of the difficulty in the synthesis of these compounds.Herein,we report the invention of a novel carbene precursor,(1-diazo-2,2,2-trifluoroethyl)dimethyl(phenyl)silane(1a)and its application in the synthesis of(difluoromethylene)cyclopropanes.The reaction proceeds through photocatalyzed[2+1]cyclization of readily available alkenes and diazo compound 1a followed by the work-up of the reaction through the elimination of silyl fluoride.Both aromatic and aliphatic alkenes are tolerated by the mild reaction conditions,affording various(difluoromethylene)cyclopropanes in 44%–82%yield(>30 examples).Gram scale reaction and diversified downstream transformations highlight the synthetic potential of this methodology.The experimental and DFT calculations suggest the involvement of triplet carbene intermediate.

关 键 词：triplet carbene CYCLOPROPANATION METHYLENECYCLOPROPANES (difluoromethylene)cyclopropanes 

分 类 号：O621.256.9[理学—有机化学]