Enantioselective reactions of scalemic acyclic alpha-(alkoxy)alkyl- and alpha-(N-carbamoyl)alkylcuprates

reaction: see text] Scalemic acyclic alpha-(alkoxy)alkyl- and alpha-(N-carbamoyl)alkylcuprates prepared from organostannanes via organolithium reagents react with vinyl iodides, propargyl mesylates, and alpha,beta-enones to afford coupled products with enantioselectivities ranging from 0 to 99% ee depending upon cuprate reagent, substrate structure, solvent, and temperature. In general, lithium cuprates give higher chemical yields and lower enantioselectivities, while the trends are reversed for the corresponding zinc cuprate reagents.