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Enantioselective reduction of ketoimines promoted by easily available (S)-proline derivativesDOI: 10.3762/bjoc.9.71 Keywords: chiral prolines , imine reduction , Lewis bases , organocatalysis , trichlorosilane Abstract: The behavior of readily synthesized and even commercially available (S)-proline derivatives, was studied in the trichlorosilane-mediated reduction of ketoimines. A small library of structurally and electronically modified chiral Lewis bases was considered; such compounds were shown to promote the enantioselective reduction of different substrates in good chemical yields. In the HSiCl3 addition to the model substrate N-phenylacetophenone imine, the organocatalyst of choice led to the formation of the corresponding amine with good stereoselectivity, up to 75% ee. Theoretical studies were also performed in order to elucidate the origin of the stereoselection.
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