Synlett 2008(10): 1571-1573  
DOI: 10.1055/s-2008-1078421
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© Georg Thieme Verlag Stuttgart · New York

Efficient Direct Alkynylation of Trifluoromethyl Ketones Catalyzed by AgF in Water and Organic Solvents

Guo-Jun Denga, Chao-Jun Li*a,b
a Department of Chemistry, Tulane University, New Orleans, LA, 70118, USA
b Department of Chemistry, McGill University, 801 Sherbrooke St. West, Montreal, QC, H3A 2K6, Canada
Fax: +1(514)3983797; e-Mail: cj.li@mcgill.ca;
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Publikationsverlauf

Received 16 October 2007
Publikationsdatum:
16. Mai 2008 (online)

Abstract

A general and efficient method for the direct alkynylation of trifluoropyruvate and trifluoroacetophenone in water was developed by using AgF and PCy3 as a catalyst. The ligand enhanced the catalyst activity significantly. The reaction in water is comparable to the one carried out in organic solvents.

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Representative Experimental Procedure
A nitrogen-flushed 10 mL flask equipped with a magnetic stirrer and a septum was charged with AgF (6.3 mg, 0.05 mmol) and PCy3 (14 mg, 0.05 mmol). Ethyl 3,3,3-trifluoro-pyruvate (85 mg, 0.5 mmol), alkyne (2 equiv), and H2O (0.5 mL) were added by using a syringe. The reaction mixture was stirred for 1-2 d at r.t. and extracted with Et2O. The organic solvent was evaporated and the residue was purified by column chromatography (SiO2, hexane-EtOAc) and characterized by means of 1H NMR, 13C NMR, IR, and HRMS.