Articolo in rivista, 2016, ENG, 10.1002/ejoc.201600897
Baglieri A.; Meschisi L.; De Sarlo F.; Machetti F.
Istituto di chimica dei composti organometallici, c/o Dipartimento di chimica Ugo Schiff, Consiglio nazionale delle ricerche (CNR), Via della Lastruccia 13, Sesto Fiorentino, Firenze, 50019, Italy; Dipartimento di chimica Ugo Schiff, Università degli studi di Firenze, Via della Lastruccia 13, Sesto Fiorentino, Firenze, 50019, Italy
Isoxazoles, mainly 3,5-disubstituted, are prepared by catalytic condensation of primary nitro compounds with terminal acetylenes by using a copper/base catalytic system. The additional catalytic effect of the copper(II) salts is evidenced by comparing the kinetic profiles. Selectivity dependence on reaction conditions is considered for phenylacetylene in the following competitive processes: oxidative coupling of terminal alkynes to conjugated diynes catalyzed by CuII and base in the presence of air; production of furazans beside condensation with benzoylnitromethane to 3-benzoylisoxazoles, as a result of the reaction of the dipolarophile with 3,4-dibenzoylfuroxan; addition of electron-poor alkynes (e.g., methyl propiolate) with themselves and with the nitro compound. Thus, oxidative coupling is negligible in reactions with "active" nitro compounds, whereas with nitroalkanes both products are observed: only trace amounts of isoxazoles are detected without copper. Similarly, in the presence of copper, 3-benzoyl-5-phenylisoxazole is predominant over the furazan. Furthermore, condensations of electron-poor alkynes give complex reaction mixtures in the presence of base alone, but cycloadducts are conveniently prepared with copper. The results indicate the practical and general utility of this catalytic method for synthetic practice.
European journal of organic chemistry (Print) 2016 (27), pp. 4643–4655
Alkynes, Copper, Homogeneous catalysis, Nitro compounds, Nitrogen heterocycles
ID: 360130
Year: 2016
Type: Articolo in rivista
Creation: 2016-11-03 08:56:31.000
Last update: 2021-04-14 10:29:28.000
CNR authors
CNR institutes
External links
OAI-PMH: Dublin Core
OAI-PMH: Mods
OAI-PMH: RDF
URL: https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/ejoc.201600897
External IDs
CNR OAI-PMH: oai:it.cnr:prodotti:360130
DOI: 10.1002/ejoc.201600897
Scopus: 2-s2.0-84988350472