Effect of Chiral Diene Ligands in Rhodium-Catalyzed Asymmetric Addition of Arylboronic Acids to α,β-Unsaturated Sulfonyl Compounds

Asymmetric addition of arylboronic acids to α,β-unsaturated
sulfonyl compounds proceeded in the presence of a rhodium catalyst
coordinated with a chiral diene ligand to give high yields of the
addition products with high enantioselectivity (96–>99.5%
ee).
The diene ligand was proved to be essential for the formation of the
addition products, while the use of a bisphosphine ligand mainly gave
the cine-substitution product.