title: Electroreductive intramolecular coupling of aromatic beta- and gamma-imino esters: a new synthetic method for N-alkoxycarbonyl-2-aryl-3-ones and cis-2-aryl-3-ols of pyrrolidines and piperidines.
abstract: The electroreduction of aromatic beta- and gamma-imino esters prepared from beta-alanine and GABA in the presence of chlorotrimethylsilane and subsequent N-alkoxycarbonylation of the resulting five- and six-membered cyclized amines gave mixed ketals of N-alkoxycarbonyl-2-arylpyrrolidin-3-ones and 2-arylpiperidin-3-ones, respectively. The best result of the electroreductive intramolecular coupling was achieved using Bu(4)NClO(4) as a supporting electrolyte and a Pb cathode in THF. Acid hydrolysis of the mixed ketals afforded N-alkoxycarbonyl-2-arylpyrrolidin-3-ones and 2-arylpiperidin-3-ones in good yields. The reduction of these ketones with NaBH(4) in methanol afforded the corresponding N-alkoxycarbonyl-cis-2-arylpyrrolidin-3-ols and cis-2-arylpiperidin-3-ols diastereospecifically.
authors.affiliation: Department of Biotechnology, Faculty of Engineering, Tottori University, Koyama, Tottori 680-8552, Japan. kise@bio.tottori-u.ac.jp
authors.forename: Naoki
authors.initials: N
authors.lastname: Kise
authors.forename: Kengo
authors.initials: K
authors.lastname: Ohya
authors.forename: Kie
authors.initials: K
authors.lastname: Arimoto
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yamashita
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Hirano
authors.forename: Tadahiro
authors.initials: T
authors.lastname: Ono
authors.forename: Nasuo
authors.initials: N
authors.lastname: Ueda
mesh_terms: D000588:Amines / Q000737:chemistry; D002384:Catalysis; D004952:Esters / Q000737:chemistry; D007098:Imino Acids / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010880:Piperidines / Q000138:chemical synthesis*; D011759:Pyrrolidines / Q000138:chemical synthesis*; D013237:Stereoisomerism; D015091:beta-Alanine / Q000737:chemistry; D005680:gamma-Aminobutyric Acid / Q000737:chemistry
chemical_list: D000588:Amines; D004952:Esters; D007098:Imino Acids; D010880:Piperidines; D011759:Pyrrolidines; D015091:beta-Alanine; D005680:gamma-Aminobutyric Acid