Rhodium-Catalyzed Asymmetric 1,4-Addition of Sodium Tetraarylborates to β,β-Disubstituted α,β-Unsaturated Esters

A rhodium-catalyzed 1,4-addition of sodium tetraarylborates to beta,beta-disubstituted alpha,beta-unsaturated esters has been developed. Highly efficient asymmetric catalysis has also been described to create quaternary carbon stereocenters at the beta-position of esters by tuning the ester group of substrates and employing a readily available chiral diene ligand.