Practical Method for Asymmetric Addition of Arylboronic Acids to α,β-Unsaturated Carbonyl Compounds Utilizing an In Situ Prepared Rhodium Catalyst

A new practical method for the asymmetric Michael addition of arylboronic acids to alpha,beta-unsaturated carboryl compounds utilizing in situ generated chiral rhodium-binap-based catalyst has been developed to address the unavailability of the preformed catalysts. While maintaining high levels of enantioselectivity reported for the preformed catalysts, the new method provides a convenient access to either enantiomeric form of the product and allows for a substantial reductions in both the boronic acid and the catalyst loads.