Enantioselective reduction secondary amides

By using glycine diphenylmethyl (Dpm) amide-derived Schiff base 22 as a key substrate and N-spiro chiral quaternary ammonium bromide lg as an ideal catalyst, a high enantioselectivity was achieved, even in the alkylation with less-reactive simple secondary alkyl halides, as shown in Table 5.5 [21]. This system offers a facile access to structurally diverse optically active vicinal diamines in combination with the subsequent reduction (Scheme 5.14) [21]. 

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