Catalytic Enantioselective Addition of Silyl Ketene Acetals to Ketones

Significance

Using a CuF/TaniaPhos/PhBF₃K catalyst system with added (EtO)₃SiF, a variety of unsymmetrical ketones and silyl ketene acetals were transformed to the corresponding chiral 3° alcohol with high levels of enantio- and diastereo­selectivity. For β-substituted silyl ketene acetals, the diastereomeric ratio is independent of the E/Z ratio of the starting material; thus this is the first example of catalytic and enantioselective addition of silyl ketene acetals to ketones.