Regio- and stereoselectivity control in palladium-catalyzed allylic alkylation of 1-cycloalkenylmethyl acetates

Enantiomerically pure allylic acetates 1a and 1b were obtained by lipase-catalyzed acylation through kinetic resolution processes of the racemates. Palladium-catalyzed alkylation of 1a with dimethyl malonate was both regio- and stereoselective, showing that no isomerization of the acetate 1a or the intermediate π-allylic palladium complex took place under the conditions used. Alkylation of 1b was stereoselective but not regioselective. The regioselectivity could be partially controlled by the proper choice of a chiral ligand. Conditions were set up to perform both the alkylation of 1b and the decarbomethoxylation of the resulting product to afford 3-(cyclohex-1-enyl) butanoate in a one-pot, one-step process.