Direct construction of quaternary carbons from carbonyl compounds utilizing low-valent vanadium complexes

Article abstract of DOI:10.1016/S0040-4020(97)00632-7

Direct geminal diallylation of a carbonyl compound with allyl bromide has been achieved in the presence of a low-valent vanadium complex and zinc. The diallylation has been found to proceed stepwise and the two allyl groups were introduced successively. By applying this method, one-pot synthesis of asymmetric quaternary carbons has been accomplished. As the first alkylating reagent a combination of allyl bromide and zinc, a Grignard reagent, or an alkyllithium can be used. The second one should be the combination of a low- valent vanadium(II) complex and allyl bromide, benzyl bromide, or propargyl bromide. Strong oxophilicity of the low-valent vanadium facilitated the deoxygenative allylation.