Metal zinc-promoted gem-bisallylation of acid chlorides with allyl chlorides in the presence of chlorotrimethylsilane

Treatment of acid chlorides (2) with allyl chlorides (1) in the presence of zinc dust and a catalytic amount of chlorotrimethylsilane (TMSCl) in THF brought about highly facile and effective coupling to give the corresponding gem-bisallylation products, 4-hydroxy-penta-1,6-dienes (3), in good to excellent yields. These reactions are assumed to proceed through allylzinc intermediates generated in situ.