Preparation of chiral 7,7′-disubstituted BINAPs for Rh-catalyzed 1,4-addition of arylboronic acids

A series of new 7,7′-disubstituted BINAPs were readily prepared starting with an asymmetric catalytic oxidative coupling. They were applied as ligands to rhodium catalyzed 1,4-addition of arylboronic acids to enones, resulting in enantioselectivities of up to 99% ee. The enantioselectivity was found to be dependent on the size of achiral substituents.