Synthesis of γ-aminobutyric acid analogues of restricted conformation. Part 1. The 2-aminocycloalkylacetic acids
作者:Peter D. Kennewell、Saroop S. Matharu、John B. Taylor、Robert Westwood、Peter G. Sammes
DOI:10.1039/p19820002553
日期:——
The syntheses of cis- and trans-2-aminocyclopropyl, -cyclobutyl, -cyclopentyl, and -cyclohexylacetic acids as γ-aminobutyricacidanalogues of restrictedconformation are described. Mass spectral evidence fully supports the stereochemical assignments of the configurational isomers.
2,3-Bis(phenylsulfonyl)-1,3-butadiene as a Reagent for the Synthesis of the Azatricyclic Core of (±)-Halichlorine
作者:Andrew C. Flick、Maria José Arevalo Caballero、Hyoung Ik Lee、Albert Padwa
DOI:10.1021/jo100055u
日期:2010.3.19
An efficient stereocontrolled route to the azatricyclic core of an advanced halichlorine intermediate is described. Reaction of the oxime derived from 2-(oxo-cyclopentyl)acetic acid ethyl ester with 2,3-bis(phenylsulfonyl)-1,3-butadiene gives rise to a 7-oxa-1-azanorbornane cycloadduct in high yield. The formation of the bicyclic isoxazolidine arises from conjugate addition of the oxime onto the diene