Conjugate Addition of Aryl Alanes to Form Quaternary Stereocenters

Significance

General methods for the formation of chiral all-carbon quaternary stereocenters in an asymmetric fashion are highly desirable. Significant progress has recently been made towards conjugate addition reactions of β,β-disubstituted enones using copper and rhodium catalysis. However, limitations still exist in the availability of inexpensive catalysts and nucleophile sources. The authors make progress towards these goals by using a commercially available rhodium catalyst and pre-formed aryl alane nucleophiles to give conjugate addition products in excellent enantio­selectivities.