An auxiliary induced asymmetric synthesis of functionalized cyclobutanes by means of catalytic (2+2)-cycloaddition reaction

A new entry to optically active hydroxycyclobutanes is described. Treatment of silyl enol ether and (−)-8-phenylmenthyl acrylate in the presence of a catalytic amount of EtAlCl2 affords enantiomerically enriched multi-substituted cyclobutane compounds in a good yield and diastereofacial selectivity.