title: Ring transformation of 2-(haloalkyl)azetidines into 3,4-disubstituted pyrrolidines and piperidines.
abstract: [reaction: see text] Reduction of 4-(haloalkyl)azetidin-2-ones with chloroalane (AlH(2)Cl) afforded new 2-(haloalkyl)azetidines in high yields. The latter compounds proved to be very useful starting materials for rearrangements toward stereospecifically defined five- and six-membered azaheterocycles, such as 3,4-cis-disubstituted pyrrolidines and piperidines. During these reactions, bicyclic azetidinium intermediates were formed which were ring opened by a variety of nucleophiles. Hereby, reactions proceeding via 1-azoniabicyclo[2.2.0]hexanes are reported for the first time.
authors.affiliation: Department of Organic Chemistry, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium.
authors.forename: Willem
authors.initials: W
authors.lastname: Van Brabandt
authors.forename: Robin
authors.initials: R
authors.lastname: Van Landeghem
authors.forename: Norbert
authors.initials: N
authors.lastname: De Kimpe