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Cinchona‐Derived Picolinamides: Effective Organocatalysts for Stereoselective Imine Hydrosilylation
Author(s) -
Barrulas Pedro C.,
Gei Andrea,
Benaglia Maurizio,
Burke Anthony J.
Publication year - 2014
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201403180
Subject(s) - hydrosilylation , chemistry , trichlorosilane , enantioselective synthesis , cinchona , imine , cationic polymerization , stereoselectivity , organocatalysis , catalysis , organic chemistry , cinchona alkaloids , medicinal chemistry , silicon
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.