Lee A, Oh S, Kim H. Synthesis of α-(4-Oxazolyl)amino Esters via Brønsted Acid Catalyzed Tandem Reaction.
Org Lett 2018;
20:3319-3322. [PMID:
29763328 DOI:
10.1021/acs.orglett.8b01212]
[Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A one-step, Brønsted acid catalyzed tandem reaction for the synthesis of α-(4-oxazolyl)amino esters was developed. 4-Nitrobenzenesulfonic acid was found to be an efficient catalyst for the coupling of ethyl 2-oxobut-3-ynoates with amides to provide various α-(4-oxazolyl)amino esters. The experimental and X-ray crystallographic data suggest that a series of bond-forming reactions including imine formation, intermolecular Michael addition, and intramolecular Michael addition are involved to generate both the oxazole and amino acid functionalities.
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