Synthesis of new aza-bicyclic 2-isoxazolines by 1,3-dipolar cycloaddition of endocyclic enecarbamates and enamides with nitrile oxides

de Almeida, VM
dos Santos, RJ
Goes, AJD
de Lima, JL
Correia, CRD
de Faria, AR

Open link

Publication date

November 2015

DOI

10.1016/j.tetlet.2008.11.096

Publisher

Inglaterra

Journal

issn:0040-4039

Abstract

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Novel aza-bicyclic 2-isoxazolines, 4,5-dihydroisoxazole[5,4-b]pyrrolidines, and 4,5-dihydroisoxazole[5,4b]piperidines were synthesized in a highly regioselective manner through a 1,3-dipolar cycloaddition reaction of 5- and 6-membered endocyclic enecarbamates and enamides with several nitrile oxides in good to excellent yields. Hydrogenolysis of 5- and 6-membered Cbz-cycloadducts led to secondary amines, which presented distinctive stabilities. 2-Isoxazoline bisamides were obtained in good yields through a N-benzoylation, followed by ammonolysis of the secondary amine, or directly from ammonolysis of the cycloadducts. (C) 2008 Elsevier Ltd. All rights reserved.506684687Cons...