C2-symmetric chiral diene ligands based on 4,8-endo,endo-disubstituted bicyclo[3.3.1]nona-2,6-diene framework have been designed and synthesized. The rhodium complexes of the dienes, which were obtained in a few straightforward steps from enantiomerically pure bicyclo[3.3.1]nonane-2,6-dione, exhibited excellent catalytic activity and high enantioselectivity (up to 96 % ee) in the conjugate addition
Chiral Bidentate Bis(N-Heterocyclic Carbene)-Based Palladium Complexes Bearing Carboxylate Ligands: Highly Effective Catalysts for the Enantioselective Conjugate Addition of Arylboronic Acids to Cyclic Enones
作者:Tao Zhang、Min Shi
DOI:10.1002/chem.200701982
日期:2008.4.18
Axiallychiral cis-chelated bidentate bis(N-heterocyclic carbene)-palladium(II) complexes with two weakly coordinating carboxylate ligands are effective catalysts for the asymmetric conjugate addition of arylboronicacids to cyclic enones, producing the corresponding adducts in moderate-to-high yields and with good-to-high enantioselectivities, in most cases under mild conditions.