Catalytic Asymmetric Direct Mannich Reactions of Carbonyl Compounds with α-Imino Esters.
The development of a direct catalytic asymmetric Mannich reaction is shown and its potential demonstrated by the synthesis of optically active lactones via 4-hydroxyglutamic acid ester derivatives. The catalytic asymmetric Mannich reaction of carbonyl compounds with α-imino esters [Eq. (1); Ts = p-toluenesulfonyl] gives good yields and diastereoselectivities, as well as excellent enantioselectivities.
Center for Metal-Catalyzed Reactions Department of Chemistry, Aarhus University 8000 Aarhus C, Denmark, Fax: (+45) 8619-6199.
K
K
Juhl
N
N
Gathergood
K A
KA
Jørgensen
Lewis acids; Mannich reactions; amino acids; asymmetric catalysis; imines