Lewis Base Activation of Lewis Acids: Catalytic, Enantioselective Addition of Silyl Ketene Acetals to Aldehydes
作者:Scott E. Denmark、Gregory L. Beutner、Thomas Wynn、Martin D. Eastgate
DOI:10.1021/ja047339w
日期:2005.3.1
The concept of Lewisbase activation of Lewisacids has been reduced to practice for catalysis of the aldolreaction of silyl ketene acetals and silyl dienol ethers with aldehydes. The weakly acidic species, silicon tetrachloride (SiCl4), can be activated by binding of a strongly Lewis basic chiral phosphoramide, leading to in situ formation of a chiral Lewisacid. This species has proven to be a competent