4,8-Disubstituted Bicyclo[3.3.1]nona-2,6-dienes as Chiral Ligands for Rh-Catalyzed Asymmetric 1,4-Addition Reactions

摘要

C-2-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 reaction of arylboronic acids to cyclic enones under mild reaction conditions with high atom efficiency.