Chiral Metallacycles as Catalysts for Asymmetric Conjugate Addition of Styrylboronic Acids to α,β-Enones
Tao Hong1, Zibin Zhang1, Yan Sun2
1College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 311121, China.
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 stereoselectivity 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).
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