Premium
Enantioselective Hydrosilylation of Ketones Catalyzed by a Readily Accessible N‐Heterocyclic Carbene–Ir Complex at Room Temperature
Author(s) -
Shinohara Kanako,
Kawabata Shun,
Nakamura Hanako,
Manabe Yoshiki,
Sakaguchi Satoshi
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.201402279
Subject(s) - hydrosilylation , chemistry , carbene , amide , ligand (biochemistry) , denticity , catalysis , enantioselective synthesis , medicinal chemistry , combinatorial chemistry , organic chemistry , crystal structure , biochemistry , receptor
A series of functionalized azolium compounds were synthesized from chiral α‐amino acid derivatives such as β‐amino alcohols. Reaction of hydroxy‐amide‐functionalized azolium salts thus obtained with Ag 2 O afforded N‐heterocyclic carbene‐Ag (NHC–Ag) complexes. Subsequent treatment of the resulting silver compound with [IrCl(cod)] 2 yielded monodentate IrCl(cod)(NHC), which was stable in air. The NHC–Ir complex facilitated efficient asymmetric hydrosilylation of ketones using (EtO) 2 MeSiH under ambient conditions. A chiral ligand containing an isobutyl stereodirecting group was found to be the best ligand for the functionalized NHC–Ir complexes that were examined. A linear relationship was found between the catalyst ee and the product ee . The hydroxy functional group on the NHC ligand side‐arm not only induced stereocontrol but also enhanced the reaction rate.