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.
Cinchona-derived picolinamides : effective organocatalysts for stereoselective Imine hydrosilylation / P. Barrulas, A. Genoni, M. Benaglia, A. Burke. - In: EUROPEAN JOURNAL OF ORGANIC CHEMISTRY. - ISSN 1099-0690. - 2014:33(2014), pp. 7339-7342.
|Titolo:||Cinchona-derived picolinamides : effective organocatalysts for stereoselective Imine hydrosilylation|
|Parole Chiave:||alkaloids; imines; Lewis bases; organocatalysis; reduction|
|Settore Scientifico Disciplinare:||Settore CHIM/06 - Chimica Organica|
|Data di pubblicazione:||2014|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1002/ejoc.201403180|
|Appare nelle tipologie:||01 - Articolo su periodico|