Organocatalyzed Asymmetric Vinylogous Addition of Oxazole-2(3H)-thiones to alpha,beta-Unsaturated Ketones: An Additive-Free Approach for Diversification of Heterocyclic Scaffold

Autor(es)

Silva, Sandrina ^[1] ; Matsuo, Bianca T. ^[1] ; da Silva, Rodrigo C. ^[1] ; Pozzi, Lucas V. ^[1] ; Correa, Arlene G. ^[1] ; Rollin, Patrick ^{[2, 3]} ; Zukerman-Schpector, Julio ^[1] ; Ferreira, Marco A. B. ^[1] ; Paixao, Marcio W. ^[1]

Afiliação do(s) autor(es)

^[1] Fed Univ Sao Carlos UFSCar, Ctr Excellence Res Sustainable Chem CERSusChem, Dept Chem, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Orleans, F-45067 Orleans - France

^[3] CNRS, ICOA, UMR 7311, BP 6759, F-45067 Orleans - France

• Tipo de documento: Artigo Científico
• Fonte: Journal of Organic Chemistry; v. 83, n. 4, p. 1701-1716, FEB 16 2018.
• Citações Web of Science: 2

Resumo

A straightforward organocatalyzed asymmetric addition of oxazole-2(3H)-thiones to alpha,beta-unsaturated ketones is described. This additive-free Michael reaction in the presence of chiral cinchonine-derived primary amines as catalysts has proven to be highly effective for a wide range of cyclic and acyclic enones, leading to the Michael adducts in very good yields and excellent enantioselectivities. The absolute configuration (R) of compound 5j was unambiguously assigned by X-ray diffraction analysis. Furthermore, experimental and theoretical studies were performed and a mechanism is presented and discussed for this novel reaction. (AU)

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