The Mannich reaction of malonates with simple imines catalyzed by bifunctional cinchona alkaloids: enantioselective synthesis of beta-amino acids.
We describe the first efficient, direct asymmetric Mannich reactions with malonates and N-Boc aryl and alkyl imines by cooperative hydrogen-bonding catalysis with a cinchona alkaloid bearing a thiourea functionality. We have also extended the scope of this reaction to beta-ketoesters. The synthetic value of this new reaction is demonstrated in the establishment of a convergent enantioselective route toward the biologically important beta-amino acids under mild and air- and moisture-tolerant conditions.
Song
Jun
J
Department of Chemistry, Brandeis University, Waltham, Massachusetts 02454-9110, USA.
Wang
Yi
Y
Deng
Li
L