Chiral norbornadienes as efficient ligands for the rhodium-catalyzed asymmetric 1,4-addition of arylboronic acids to fumaric and maleic compounds.

[reaction: see text] A rhodium-catalyzed asymmetric 1,4-addition of arylboronic acids to fumaric and maleic compounds has been developed. While phosphorus-based chiral ligands fail to induce high stereoselectivity, chiral norbornadiene ligands have proved to be uniquely effective to achieve high enantioselectivity in these 1,4-addition reactions.