Highly Stereoselective Palladium(0)-Catalyzed Allylation of Active Methylene Compounds with Allyl Imidates under Neutral Conditions

In the presence of a catalytic amount of Pd(0), active methylene compounds were allylated by allyl imidates under neutral conditions. In allylation with 3,3-disubstituted allyl imidates, e.g., geranyl and neryl imidate the effect of solvent and ligand to the E/Z ratio are investigated. The reaction in dimethyl sulfoxide by addition of diphosphine, e.g., 1,2-bis(diphenylphosphino)ethane, or large excess of triphenylphosphine as additive ligand gave best results. In these conditions, various active methylene compounds were allylated stereoselectively, especially complete retention of starting olefin geometry was achieved with neryl imidate.