Copper catalyzed access to functionalized oxazoles from oximes via carbenoids. Issue 23 (6th June 2018)

• Record Type: Journal Article
• Authors: Nagaraju, Anugula; Sandeep, K.; Kumara Swamy, K.C.
• Is Part Of: Tetrahedron letters. Volume 59:Issue 23(2018)
• Page Start: 2238
• Page End: 2242
• Publication Date: 2018-06-06
• Subjects: Oxazole -- Oxime -- Diazo acetate -- Carbenoid -- Copper catalyzed; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2018.05.004
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Highlights: Functionalized oxazoles are prepared using copper catalysis. Oximes and carbenoid precursors have been utilized. Two reducible functionalities (esters or ester + cyano) are introduced on oxazoles. Abstract: An operationally simple, economical and straightforward synthesis of diverse oxazoles from oximes possessing a vicinal carbonyl group has been achieved by treatment of the latter with terminal diazo compounds like ethyl/benzyl diazoacetate and diazoacetophenone (which act as carbenoids) in one pot. At least two reducible functional groups (two ester groups or cyano + ester) are simultaneously introduced in one step. This reaction involves expulsion of a molecule each of N2 and water only as byproducts under copper catalysis. The structure of one of these oxazoles is confirmed by X-ray crystallography. Both the ester groups in the oxazole product could be reduced to alcohol moieties by using NaBH4 /EtOH.