Enantioselective synthesis of tertiary boronic esters through catalytic asymmetric reversed hydroboration

Chiral tertiary boronic esters are important precursors to bioactive compounds and versatile synthetic intermediates to molecules containing quaternary stereocenters. The development of conjugate boryl addition to alpha,beta -unsaturated amide has been hampered by the intrinsic low electrophilicity of the amide group. Here we show the catalytic asymmetric synthesis of enantioenriched tertiary boronic esters through hydroboration of beta,beta -disubstituted alpha,beta -unsaturated amides. The Rh-catalyzed hydroboration occurs with previously unattainable selectivity to provide tertiary boronic esters in high enantioselectivity. This strategy opens a door for the hydroboration of inert Michael acceptors with high stereocontrol and may provide future applications in the synthesis of biologically active molecules. The development of conjugate boryl addition to alpha,beta -unsaturated amide has been hampered by the intrinsic low electrophilicity of the amide group. Here the authors show a catalytic asymmetric synthesis of enantioenriched tertiary boronic esters through hydroboration of beta,beta -disubstituted alpha,beta -unsaturated amides.

Automated summary

The research team successfully synthesized chiral tertiary boronic esters through hydroboration, providing a method with high stereocontrol for inert Michael acceptors and potential applications in the synthesis of biologically active molecules.