Intermolecular rhodium catalyzed hydroacylation of allenes: the regioselective synthesis of β,γ-unsaturated ketones

A variety of β-S-substituted aldehydes undergo efficient and regioselective rhodium catalyzed hydroacylation reactions with 1,3-disubstituted and 1,1,3-trisubstituted allenes, to deliver β,γ-unsaturated ketone products. Regioselectivites are controlled primarily by steric factors. The reactions are catalyzed by the complex [Rh(dppe)]ClO4.