[摘要]:A highly efficient diastereoselective Mannich reaction has been carried out in water using a catalytic amount of beta-cyclodextrin as a chiral host in the presence of acetic acid to give the corresponding beta-aminoketones (Mannich bases) with good yield (up to 98%) and excellent diastereomeric excess (up to >99%). This Bronsted acid-chiral cyclodextrin composite catalyzed reaction proceeds in a syn-selective manner with 98:2 syn/anti selectivity when propiophenone is used as the ketone moiety and in an anti-selective manner with 100: 0 (anti/syn) selectivity when cyclohexanone is used. |