Organocatalysis with a fluorous tag: Asymmetric reduction of imines with trichlorosilane catalyzed by amino acid-derived formamides

[GRAPHIC] Asymmetric reduction of ketimines 1 with trichlorosilane can be catalyzed by N-methylvaline-derived Lewis-basic formamides 3a-d with high enantioselectivity (<= 95% ee) and low catalyst loading (1-5 mol %) at room temperature in toluene. Appending a fluorous tag, as in 5a-c, simplifies the isolation procedure, while preserving high enantioselectivity (<= 92% ee).