Enantioselective construction of substituted hydantoins via chiral phosphoric acid catalyzed annulation/Heyns rearrangement of aryl-substituted ureas with glyoxals

Abstract

Herein, the de novo organocatalyzed enantioselective construction of hydantoins from simple urea and glyoxal is reported. A chiral phosphoric acid (CPA) catalyzed [3 + 2] heteroannulation/enantioselective Heyns rearrangement is proposed to be involved in this transformation. The Heyns rearrangement smoothly proceeded via a proton-transfer process involving an enol intermediate. The CPA served as a chiral proton-transfer shuttle to control the enantioselectivity.