Chiral Metallacycles as Catalysts for Asymmetric Conjugate Addition of Styrylboronic Acids to α,β-Enones

Abstract

Introducing self-assembly strategies into the construction of catalysts has been proven to have great advantages in asymmetric catalysis. We constructed two chiral metalla-triangles by highly efficient coordination-driven self-assembly from a chiral 3,3’-dipyridyl substituted BINOL donor. They were successfully applied in asymmetric conjugate addition of a series of α,β-unsaturated ketones with trans-styrylboronic acids. The use of these metalla-triangles as supramolecular catalysts is obviously conducive to the enhancement of catalytic activity and stereose-lectivity in the presented addition reactions. Under induction of the chiral metalla-triangles, an array of α,β-enones were converted to chiral γ,δ-unsaturated ketones in medium to quantitative yields (40–98%) with high enantioselectivities (87–96% ee).