Sc(OTf)<sub>3</sub>-Catalyzed Conjugate Allylation of Alkylidene Meldrum’s Acids
作者:Aaron M. Dumas、Eric Fillion
DOI:10.1021/ol9003959
日期:2009.5.7
Alkylidene Meldrum’s acids are allylated in a conjugate fashion by allyltin nucleophiles under mild Sc(OTf)3-catalyzed conditions. The addition is functional group tolerant and reactions with nonracemic alkylidenes are highlydiastereoselective. Allylation of alkylidenes derived from α-ketoesters yield all-carbon quaternary stereocenters.
Asymmetric Synthesis of Carboxylic Acid Derivatives Having an All-Carbon α-Quaternary Center through Cu-Catalyzed 1,4-Addition of Dialkylzinc Reagents to 2-Aryl Acetate Derivatives
作者:Ashraf Wilsily、Eric Fillion
DOI:10.1021/ol800923q
日期:2008.7.3
The asymmetric synthesis of carboxylicacidderivatives having an all-carbon alpha-quaternary center has been achieved via copper-catalyzed 1,4-addition of dialkylzinc reagents to aryl acetate derivatives in the presence of phosphoramidite ligand. High isolated yields and enantioselectivities were obtained. It was demonstrated that the Meldrum's acid and ester moieties present on the all-carbon quaternary