Regiocontrolled and Stereocontrolled Diels-Alder Cycloadditions of 2-Pyrones and Unactivated, Unbranched 1-Alkenes

Abstract

The combination of 10-12 kbar pressure plus a catalytic amount of either zinc dibromide or zinc dichloride promotes Diels-Alder cycloadditions of 3-bromo-2-pyrone and of commercial 3-methoxycarbonyl-2-pyrone with several unactivated terminal alkenes, leading regioselectively, stereoselectively and directly to versatile bicyclic lactones.