Enantioselective direct aldol reaction of α-keto esters catalyzed by (Sa)-binam-d-prolinamide under quasi solvent-free conditions
作者:Santiago F. Viózquez、Abraham Bañón-Caballero、Gabriela Guillena、Carmen Nájera、Enrique Gómez-Bengoa
DOI:10.1039/c2ob25224d
日期:——
(Sa)-Binam-D-prolinamide (20 mol%), instead of (Sa)-binam-L-prolinamide, in combination with chloroacetic acid (100 mol%) is an efficient organocatalyst for the directaldolreaction between α-ketoesters as electrophiles and alkyl and α-functionalised ketones, under quasi solvent-free conditions, providing access to highly functionalised chiral quaternary γ-keto α-hydroxyesters with up to 92% ee.
complex-catalyzed ketoester-ene reaction with silyl enol ether can be achieved to produce an ene product with a quaternary carbon center in high yield and enantioselectivity. Even lower catalyst loading (up to 0.01 mol%) can be performed without a significant decrease in yield and enantioselectivity; this will open doors to industrial applications of chiral Lewisacidcatalysis.