Javed E, Guthrie JD, Neu J, Chirayath GS, Huo S. Introducing an α-Keto Ester Functional Group through Pt-Catalyzed Direct C-H Acylation with Ethyl Chlorooxoacetate.
ACS OMEGA 2020;
5:8393-8402. [PMID:
32309750 PMCID:
PMC7161214 DOI:
10.1021/acsomega.0c00982]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 03/25/2020] [Indexed: 06/11/2023]
Abstract
Platinum-catalyzed selective C-H acylation of 2-aryloxypyridines with ethyl chlorooxoacetate provides an efficient way of introducing an α-keto ester functional group. The reaction is oxidant-free, additive-free, and, more significantly, free of any decarbonylative side reactions. The reaction tolerates a variety of substituents from strongly electron-donating to strongly electron-withdrawing groups. Double acylation is feasible for 2-phenoxypyridine and its derivatives with only one substituent at the para position. Although the reaction of 2-(2-methylphenoxy)pyridine with ethyl malonyl chloride did not produce the desired β-keto ester, the reaction with ethyl succinyl chloride proceeded smoothly to give the γ-keto ester. Ethyl chlorooxoacetate is much more reactive than ethyl succinyl chloride in this Pt-catalyzed C-H acylation reaction.
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