RESUMO
1,3-Diamine-derived catalysts were designed, synthesized, and used in asymmetric Mannich reactions of ketones. The reactions catalyzed by one of the 1,3-diamine derivatives in the presence of acids afforded the Mannich products with high enantioselectivities under mild conditions. In most cases, bond formation occurred at the less-substituted α-position of the ketone carbonyl group. Our results indicate that the primary and the tertiary amines of the 1,3-diamine derivative cooperatively act for the catalysis.
RESUMO
Mannich-type reactions of cyclohexanone and related six-membered-ring ketones with N-p-methoxyphenyl-protected imines of arylaldehydes catalyzed by 3-pyrrolidinecarboxylic acid in the presence of K2CO3 that afford anti-isomers of the Mannich products with high diastereo- and enantioselectivities are reported. Addition of K2CO3 improved the enantioselectivities of the reactions catalyzed by 3-pyrrolidinecarboxylic acid while retaining the anti-selectivity of the reaction. Thus, the use of K2CO3 expands the scope of these organocatalytic reactions for providing the products with high enantioselectivities.
RESUMO
A short and highly efficient synthetic approach to enantiopure functionalized amino acids (FAAs) 1 skeleton from racemic butadiene monoepoxide as a starting material and its application to the total synthesis of an antiepileptic drug (R)-lacosamide 2 are described. The synthesis utilizes the palladium catalyzed Trost's Dynamic Kinetic Asymmetric Transformation (DYKAT) as key step.