Catalytic asymmetric addition of diphenylzinc to cyclic alpha,beta-unsaturated ketones.

We have examined the use of our bis(sulfonamide) diol ligand (1) in the asymmetric addition of phenyl groups to cyclic alpha,beta-unsaturated ketones. Good to excellent enantioselectivities have been obtained with cyclic enones bearing alkyl substituents in the 2 position (71-97% enantiomeric excess). Furthermore, excellent enantioselectivities have been observed in the asymmetric phenylation of cyclic enones with 2-iodo and 2-bromo substituents. The results of this study broaden the scope of the asymmetric additions to ketones promoted by the titanium catalyst derived from ligand 1.