A Highly Diastereo- and Enantioselective Copper(I)-Catalyzed Henry Reaction Using a Bis(sulfonamide)-Diamine Ligand

A series of bis(sulfonamide)-diamine (BSDA) ligands were synthesized from commercially available chiral alpha-amino alcohols and diamines. The chiral BSDA ligand 3a, coordinated with Cu(I), catalyzes the enantioselective Henry reaction with excellent enantioselectivity (up to 99%). Moreover, with the assistance of pyridine, a CuBr-3a system promotes the diastereoselective Henry reaction with various aldehyde substrates and gives the corresponding syn-selective adduct with up to a 99% yield and 32.3:1 syn/anti selectivity. The enantiomeric excess of the syn adduct was 97%.