Chiral Bicyclic Bridgehead Phosphoramidite (Briphos) Ligands for Asymmetric Rhodium-Catalyzed 1,2-and 1,4-Addition

Abstract

A complementary solution for Rh-catalyzed enantioselective 1,2- and 1,4-arylation with two structurally related chiral ligands is reported. A chiral bicyclic bridgehead phosphoramidite (briphos) ligand.derived from 1-aminoindane was efficient for the 1,2-arylation of N-sulfonyl imines, while that derived from 1,2,3,4-tetrahydro-1-naphthylamine was efficient for 1,4-arylation of alpha,beta-unsaturated cyclic ketones. For alpha,beta-unsaturated N-tosyl ketimines, the briphos derived from 1-aminoindane was found to selectively provide gamma,gamma-diaryl N-tosyl enamines with high yields and stereoselectivities.