Catalytic, asymmetric synthesis of α-phenoxy-β-aryl-β-lactams

The reactions of phenoxyacetyl chloride with aryl imines in the presence of catalytic quantities of a silyl cinchona alkaloid and an achiral Lewis acid affords α-phenoxy-β-aryl-β-lactams. These reactions presumably proceed by way of ketene or acyl ammonium enolate intermediates. These reactions occur in a high enantioselectivity regardless of the nature of the Lewis acid, however, a high diastereoselectivity depended on the use of a hindered lanthanide complex as the Lewis acidic co-catalyst.