Enantioselective Conjugate Addition of Silylketene Acetals to β-Enamidomalonates. Synthesis of β-Amino Acid Derivatives
作者:Mukund P. Sibi、Jianxie Chen
DOI:10.1021/ol026333d
日期:2002.8.1
Conjugate addition of silylketene acetals or enolsilanes to enamidomalonates proceeds with excellent chemical efficiency and good selectivity using Cu(OTf)(2) and a chiral bisoxazoline. The effect of the Lewis acid, ligand, the N-acyl substituent, and the nucleophile on yield and selectivity for the addition product have been evaluated.
Copper(I)-Catalyzed Disilylation of Alkylidene Malonates Employing a Lewis Base Activation Strategy
作者:Christopher T. Clark、Jason F. Lake、Karl A. Scheidt
DOI:10.1021/ja038530t
日期:2004.1.1
The disilylation of activated alpha,alpha-unsaturated esters has been accomplished by utilizing symmetrical disilanes and catalytic quantities of copper(I) salts in the presence of Lewis bases such as DMF. This new methodology with various alkylidene malonates is moderate to high yielding and affords alpha-silyl diesters, compounds that previously have not been readily accessible, that can be further manipulated to cleanly afford useful alpha-substituted alpha-hydroxy esters.
Enantioselective Conjugate Addition of Organomagnesium Amides to Enamidomalonates: Synthesis of Either Enantiomer of β-Amino Acid Derivatives