M-Chloroperbenzoic acid-oxchromium (VI)-mediated cleavage of 2, 4, 5-trisubstituted oxazoles. Issue 13 (29th March 2017)

• Record Type: Journal Article
• Authors: Patil, Pravin C.; Luzzio, Frederick A.
• Is Part Of: Tetrahedron letters. Volume 58:Issue 13(2017)
• Page Start: 1280
• Page End: 1282
• Publication Date: 2017-03-29
• Subjects: Cleavage -- Oxazoles -- Oxochromium (VI) -- Peroxides -- Triacylamines; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2017.02.027
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Highlights: A new method for the cleavage of 2, 4, 5-trisubstituted oxazoles to imides and triacylamines is detailed. The oxidation system utilizes two reagents composed of a peroxide and oxochromium (VI). Mechanisms are proposed for the oxidative cleavage reaction. A synthesis of (±)-phoracantholide seco -acid is detailed. Abstract: An array of 2-substituted-4, 5-diphenyloxazoles were found to be cleaved to triacylamines and diacylamines (imides) using a reagent system composed of m -chloroperbenzoic acid (MCPBA) and 2, 2′-bipyridinium chlorochromate (BPCC). The 2-alkyl-4, 5-diphenyloxazoles give imides (38–60%) as the predominant cleavage product while the 2-aryl-4, 5-diphenyloxazoles give triacylamines (44–71%). Two mechanisms involving intermediates such as cyclic endoperoxides or oxachromacycles were proposed. An application of the oxidative cleavage to the multi-step synthesis of (±)-phoracantholide I seco acid is detailed.