Influence of the gegenion in the transmetalation reaction of vinylic tellurides with higher order cyanocuprates

Article abstract of DOI:10.1016/S0040-4039(00)73112-1

Dilithium cyanocuprates R²LCu(CN)Li₂ (L=2-Th, Me) react with vinylic tellurides of Z configuration, RCH=CHTeR¹ to give higher order vinylic cyanocuprates, [(RCH=CH)LCu(CN)Li₂]. By changing the gegenion from lithium to magnesium [R²LCu(CN)LiMgBr or R²LCu(CN)(MgBr)₂] the reaction gives cross - coupling products of Z configuration, RCH=CHR₂ in good yields.