Electron-transfer processes. 43. Attack of alkyl radicals upon 1-alkenyl and 1-alkynyl derivatives of tin and mercury

Article abstract of DOI:10.1021/om00093a020

Alkyl radicals, obtained by reaction of Bu₃Sn^? or ClHg^? with alkylmercury halides, will undergo regioselective and in some cases stereospecific substitution by a free radical chain addition-elimination mechanism with 1-alkenylstannanes or -mercurials. The chain reaction is also observed for 1-alkynyl derivatives and in the photostimulated demercuration of mixed alkyl and 1-alkenyl- or 1-alkynylmercurials. Chain propagation with alkyl radical formation is also observed to occur in the reactions of β-eliminated ClHg^? with Grignard reagents in PhH-THF solution. In competitive reactions of Bu₃Sn^? or ClHg^? with pairs of alkylmercury chlorides, it is observed that a tert-butylmercurial is >1000 times more reactive than a n-butylmercurial, suggesting a concerted dissociate electron-transfer process not involving the intermediacy of RHg^? species.