Various α-sulfonylcarbanions have been shown to react at low temperature with di- or tri-halogenolithiocarbenoïds, to give 1-mono- or 1,1-di-halogenoalkenes. Bromocarbenoïds gave better results than their chloro-analogues. Reaction of di-bromolithiomethane with α-lithiated sulfones gives a high yield of vinylic bromides, the stereochemistry of which is cleanly E. Evidence is presented that the carbenoïd
Iridium‐Catalyzed Hydrochlorination and Hydrobromination of Alkynes by Shuttle Catalysis
作者:Peng Yu、Alessandro Bismuto、Bill Morandi
DOI:10.1002/anie.201912803
日期:2020.2.10
Described herein are two different methods for the synthesis of vinyl halides by a shuttle catalysis based iridium-catalyzed transfer hydrohalogenation of unactivated alkynes. The use of 4-chlorobutan-2-one or tert-butyl halide as donors of hydrogen halides allows this transformation in the absence of corrosive reagents, such as hydrogen halides or acid chlorides, thus largely improving the functional-group
Silafunctional compounds in organic synthesis. 32. Stereoselective halogenolysis of alkenylsilanes: stereochemical dependence on the coordination state of the leaving silyl groups