Direct organocatalytic asymmetric Mannich-type reactions in aqueous media:: one-pot Mannich-allylation reactions

The first direct organocatalytic asymmetric Mannich-type reactions in aqueous media are demonstrated herein. L-Proline-catalyzed reactions in aqueous media to provide beta-formyl substituted alpha-amino acid derivatives with excellent diastereoselectivities (dr up to 19:1, syn/anti) and high enantioselectivities (ee between 72 and >99%). These conditions provided for the development of novel one-pot asymmetric syntheses of cyclic gamma-allyl substituted alpha-amino acid derivatives (ee up to >99%). This was accomplished by combining the proline-catalyzed Mannich-type reactions with indium promoted allylations in aqueous media. (C) 2003 Elsevier Science Ltd. All rights reserved.