title: The aminomethylation of electron-rich aromatics with an N-silyl-N,O-acetal catalyzed by a metal triflate-TMSCl system: facile synthesis of aromatic primary amines, 1-aryl-trichloroethylamines.
abstract: The copper(II) triflate- and hafnium(IV) triflate-catalyzed aminomethylation of indole (2) with an N-silyl-N,O-acetal 1 containing a trichloromethyl group provides the primary amine derivative (3a) in modest yield. When 1 equiv of trimethylchlorosilane (TMSCl) was added to the reaction mixture, the reaction proceeded smoothly, and the yield of 3a was dramatically improved (>90%). The use of this catalytic system permitted the introduction of an aminomethyl group onto indoles 2a-h bearing a variety of functional groups, which appears to deactivate the Lewis acid, in 52-92% yields. Hf(OTf)4-doped TMSCl catalyzed the successful aminomethylation of various electron-rich aromatic compounds 4a-j to produce 1-aryl-trichloroethylamine derivatives 5a-j.
authors.affiliation: Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba 278-8510, Japan. sakachem@rs.noda.tus.ac.jp
authors.forename: Norio
authors.initials: N
authors.lastname: Sakai
authors.forename: Maki
authors.initials: M
authors.lastname: Hirasawa
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Hamajima
authors.forename: Takeo
authors.initials: T
authors.lastname: Konakahara