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Indexed by:期刊论文

Date of Publication:2014-08-05

Journal:TETRAHEDRON

Included Journals:SCIE、Scopus

Volume:70

Issue:31

Page Number:4668-4674

ISSN No.:0040-4020

Key Words:Metathesis; Trifluoromethyl ketones; Esters; DFT

Abstract:A highly selective and atom efficient 'trifluoroacetic ester/ketone metathesis' has been sincerely witnessed. Enolizable alkyl (at least two non-hydrogen atoms) aryl ketones were found to react readily with ethyl trifluoroacetate under the promotion of NaH to afford trifluoroacetic ester/ketone exchange products, trifluoromethyl ketones (TFMKs), and aromatic acid esters, which were quite different from the general Claisen condensation products, 1,3-diketones. The outcome of the reaction between ketone and ethyl trifluoroacetate is strongly related to the structures of substrates, the steric congestion caused by alkyl group is in favor of the C-C bond cleavage. DFT investigation further disclosed that the metathesis reaction was a kinetically favored pathway. Using only a slight excess of cheap trifluoromethylation reagent, simple operation and mild conditions make it a practical method for preparation of TFMKs on large scale, as well as a new choice of converting aryl alkyl ketones to aromatic acid esters. (C) 2014 Elsevier Ltd. All rights reserved.