Alkenylation of C-H Bonds via Reaction with Vinyl and Dienyl Triflones, Siereospecific Synthesis of Trisubstituted Vinyl Triflones via Organocopper Addition to Acetylenic Triflones

摘要

We recently reported that reaction of ethers, sulfides, and hydrocarbons with acetylenic triflones such as 2a,b provides facile access to substituted alkynes 3 (Scheme 1). The reaction proceeds via radical C-H abstraction3 by the very electrophilic trifluoromethyl radical 4~4 in a process involving addition of alkyl radical 5 to the ex-carbon of the acetylenic triflone 2 followed by elimination of the vinyl radical 6 to alkyne 3 and trifluo-romethylsulfonyl radical 7. Fragmentation of 7 to sulfur dioxide and the trifluoromethyl xadical 4 propagates the chain.