| Abstract
| - The catalytic enantioselective addition of an acetate enolate equivalent to ketones is described.Methyl trichlorosilyl ketene acetal reacts with a wide range of ketones in the presence of pyridineN-oxide to afford the aldol addition products in excellent yields. Chiral 2,2‘-pyridyl bis-N-oxidesbearing various substituents at the 3,3‘- and 6,6‘-positions also provide excellent yields of the aldolproducts with variable enantioselectivities ranging from 94/6 er for aromatic ketones to nearlyracemic for aliphatic ketones. An X-ray crystal structure of the complex between a catalyst andsilicon tetrachloride (((P)-(R,R)-19·SiCl4)) has been obtained. Extensive computational analysisprovides a stereochemical rationale for the observed trends in enantioselectivities.
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