Cinchona-Derived Picolinamides: Effective Organocatalysts for Stereoselective Imine Hydrosilylation

• Autor(a) principal: Burke, Anthony
• Data de Publicação: 2014
• Outros Autores: Barrulas, Pedro, Benaglia, Maurizio, Andrea, Genoni
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10174/13455; https://doi.org/10.1002/ejoc.201403180
• topic: Organocatálise; Hidrosililação

Picolinamide-cinchona organocatalysts for the successful enantioselective reduction of ketomines were developed. For the first time, a new type of chiral Lewis base, a cationic species, is reported to efficiently organocatalyze the addition of trichlorosilane to imines. Excellent yields with good to high enantioselectivities (up to 91%) were obtained in the reduction of differently substituted substrates. Noteworthy, remarkably high turnover frequencies for the hydrosilylation of imines were observed; the catalyst of choice proved to be active even at a loading of only 1 mol-%. The loading was further reduced to 0.5 mol-%, and for very short reaction times (15 min) very impressive asymmetric catalyst efficiency speed values were reached.