Asymmetric construction of quaternary stereocenters by direct organocatalytic amination of alpha-substituted alpha-cyanoacetates and beta-dicarbonyl compounds.
The first organocatalytic highly enantioselective reactions of substituted alpha-cyanoacetates and beta-dicarbonyl compounds with azodicarboxylates are reported. In the presence of 0.1-5 mol % of a quinidine-derived alkaloid beta-ICD, optically active quaternary hydrazine adducts are obtained in very high yields and with enantioselectivities up to >98% ee. A two-step procedure for the cleavage of the hydrazine N-N bond using SmI2 is also demonstrated.
Saaby
Steen
S
The Danish National Research Foundation, Center for Catalysis, Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark.
Bella
Marco
M
Jørgensen
Karl Anker
KA