Catalytic Enantioselective Mannich-Type Reactions of Ketoimines

Significance

The authors describe the enantio­selective Mannich-type reaction using silyl ketene acetals and ketoimines as substrates. CuOAc was shown to be the best copper source. Very high ee values were obtained for aryl,alkyl-ketoimines, while slightly lower ee values were obtained for alkyl,alkyl-keto­imines. The use of a DuPHOS derivative proved to be the optimal chiral ligand for alkyl,alkyl-ketoimines, while DTBM-SEGPHOS was best for aryl,alkyl-ketoimines. Use of a silicon-containing additive proved necessary for catalyst turnover. Removal of the N-phosphinoyl group was shown to proceed with 3 N HCl in THF.