Chiral Integrated Catalysts Composed of Bifunctional Thiourea and Arylboronic Acid: Asymmetric Aza-Michael Addition of α,β-Unsaturated Carboxylic Acids

Abstract

The first intermolecular asymmetric Michael addition of nitrogen-nucleophiles to α,β-unsaturated carboxylic acids was achieved through a new type of arylboronic acid equipped with chiral aminothiourea. The use of BnONH₂ as a nucleophile gives a range of enantioenriched β-(benzyloxy)amino acid derivatives in good yields and with high enantioselectivity (up to 90% yield, 97% enantiomeric excess (ee)). The obtained products are efficiently converted to optically active β-amino acid and 1,2-diamine derivatives.

Graphical Abstract