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Published on: September 8, 2013
Difluoroketenimine: Generation from Difluorocarbene and Isocyanide and Its [3 + 2] Cycloadditions with Alkenes or
Rui Zhang1, Zhikun Zhang1, Kang Wang1
1Beijing National Laboratory of Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China.
Abstract:
Ketenimines have been explored as useful building blocks for the synthesis of heteroatom-containing cyclic compounds through the cycloaddition with polar multiple bonds. Herein, we report the cycloaddition of difluoroketenimine with nonpolar multiple bonds, namely, the cycloaddition with alkenes or alkynes. The difluoroketenimine is generated from the coupling of tert-butyl isocyanide and difluorocarbene, which is formed in situ from (bromodifluoromethyl)trimethylsilane. The difluoroketenimine then reacts in situ with alkenes or alkynes to afford fluorinated pyrrolidines or pyrroles. DFT study suggests that a fluorinated cyclic (alkyl)(amino)carbene is involved as the key intermediate in these reactions.
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