1,3- versus 1,4-[π4+π2] Cycloadditions between methyl glyoxylate oxime and cyclopentadiene or cyclopentene

Autor:	Xerardo García-Mera, Carlos Sousa, M. Luísa C. Vale, José E. Rodríguez-Borges
Rok vydání:	2012
Předmět:	Cyclopentadiene Stereochemistry Organic Chemistry Glyoxylate cycle Oxime Biochemistry Cycloaddition Adduct chemistry.chemical_compound chemistry Drug Discovery Cyclopentene Aza-Diels–Alder reaction Octane
Zdroj:	Tetrahedron. 68:1682-1687
ISSN:	0040-4020
DOI:	10.1016/j.tet.2011.12.073
Popis:	The acid catalyzed cycloaddition reaction of methyl glyoxylate oxime with cyclopentadiene (CPD) afforded the corresponding aza-Diels–Alder adducts, the endo and exo isomers of (±)-methyl 2-hydroxy-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylates, and as the major product a 1,3-cycloadduct, methyl (1RS,4RS,5RS)-(2-oxa-3-azabicyclo[3.3.0]oct-7-ene)-4-carboxylate. The similar reaction using cyclopentene (CP) provided only the 1,3-cycloadduct methyl (1SR,4RS,5SR)-(2-oxa-3-azabicyclo[3.3.0]octane)-4-carboxylate. The influence of various parameters on the reaction outcome was studied and, based on the results obtained, a mechanism for the formation of both 1,3- and 1,4-cycloadducts is proposed. The structure of all adducts was confirmed by NMR spectroscopic data and/or by X-ray crystallography.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::74cf378953bd8cf7d052720505220728 https://doi.org/10.1016/j.tet.2011.12.073 Zobrazit plný text záznamu Full Text from ScienceDirect