Enantioselective synthesis of homoallylic amines. Evidence of reversible addition of allylzinc bromide to aromatic imines derived from (S)-valine methyl ester and (S)-valinol

Abstract

The reaction of aromatic and aliphatic imines derived from (S)-valine methyl ester and (S)-valinol with allyl bromide and zinc in tetrahydrofuran affords homoallylic amines with up to 100% diastereoisomeric excess (d.e.), but in the case of the aromatic imines the diastereoselectivity is lowered by increasing the reaction time, owing to the reversibility of the allylation reaction.