Ring Transformation of 2-(Haloalkyl)azetidines into 3,4-Disubstituted Pyrrolidines and Piperidines
作者:Willem Van Brabandt、Robin Van Landeghem、Norbert De Kimpe
DOI:10.1021/ol0530676
日期:2006.3.1
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.
Reduction of 4-(Haloalkyl)azetidin-2-ones with LiAlH<sub>4</sub> as a Powerful Method for the Synthesis of Stereodefined Aziridines and Azetidines
作者:Willem Van Brabandt、Yves Dejaegher、Robin Van Landeghem、Norbert De Kimpe
DOI:10.1021/ol053015g
日期:2006.3.1
[reaction: see text] A new synthesis of stereodefined aziridines and azetidines, starting from 4-(1- or 2-haloalkyl)azetidin-2-ones, is described. Treatment of the latter compounds with LiAlH(4) gave 1,2-fission of the beta-lactam, followed by an intramolecular nucleophilic substitution of the halogen, giving rise to the formation of 2-(1-alkoxy-2-hydroxyethyl)aziridines in the case of 4-(1-haloalkyl)azetidin-2-ones