title: Preparation of Substituted Alkylpyrroles via Samarium-Catalyzed Three-Component Coupling Reaction of Aldehydes, Amines, and Nitroalkanes.
abstract: Pyrroles were synthesized by three-component coupling reaction of aldehydes, amines, and nitroalkanes in the presence of a catalytic amount of a samarium species under mild conditions. The reaction is considered to involve the coupling of alpha,beta-unsaturated imines, which are provided by the samarium-catalyzed aldol-type condensation of imines generated from amines and aldehydes, with nitroalkanes. In the case of the three-component coupling of alpha,beta-unsaturated aldehydes (or ketones) with amines and nitroalkanes, alkylpyrroles were obtained by only heating in the absence of any catalyst. For instance, a mixture of butylamine, 2-butylidenecyclohexanone, and nitroethane, allowed to react at 60 degrees C for 15 h, produced isoindole, 4r, which is difficult to prepare by conventional methods, in 39% yield.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering & High Technology Research Center, Kansai University, Suita, Osaka 564-8680, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shiraishi
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nishitani
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sakaguchi
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Ishii