Synthesis of Chiral Tertiary Organoboronic Esters by Conjugate Addition

Significance

Enantioenriched alkyl boron derivatives have recently become of increased interest due to their ability to undergo stereoretentive transformations. An increasingly important method for the synthesis of chiral alkyl boron species is the copper-catalyzed conjugate addition of B₂pin₂. The range of electrophiles that can be used in this reaction has become quite diverse; however, challenges still remain. Acyclic β,β-disubstituted substrates species often react sluggishly or with low enantioselectivities. The authors present a copper-catalyzed conjugate addition of a boron nucleophile to β,β-disubstituted unsaturated esters, providing chiral β-boryl carbonyl compounds with high yields and enantioselectivities.