Reactivities of mixed organozinc and mixed organocopper reagents: 1 – Solvent controlled organic group transfer from mixed diorganozincs

The selectivity of organyl group transfer in the copper catalyzed benzoylation of n-butyl phenylzinc in THF depends on N-, O- or P-donor cosolvents and additives as well as copper salts and Lewis acids. In THF:NMP (3:1) and in THF:diglyme (2:1), n-butyl group/ phenyl group transfer ratio is 9:1 whereas only n-butyl group transfer is observed in THF:n-Bu3P (1 equiv.) and only phenyl group transfer is observed in THF:TMEDA (2:1).