Enantioselective reduction of ketoimines promoted by easily available (S)-proline derivatives

• Main Authors: Martina Bonsignore, Maurizio Benaglia, Laura Raimondi, Manuel Orlandi, Giuseppe Celentano
• Format: Article
• Language: English
• Published: Beilstein-Institut 2013-04-01
• Series: Beilstein Journal of Organic Chemistry
• Subjects: chiral prolines; imine reduction; Lewis bases; organocatalysis; trichlorosilane
• Online Access: https://doi.org/10.3762/bjoc.9.71

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.