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Synlett 2011(17): 2562-2566  
DOI: 10.1055/s-0030-1260336
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Highly Efficient Copper- and Palladium-Free One-Pot Coupling of Alkynes with Sodium Carboxylate Salts Using Cyanuric and Magnesium Chlorides

Mohammad Navid Soltani Rad*, Somayeh Behrouz*
Department of Chemistry, Shiraz University of Technology, Shiraz 71555-313, Iran
Fax: +98(711)7354520; e-Mail: soltani@sutech.ac.ir; e-Mail: behrouz@sutech.ac.ir;
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Publication History

Received 31 July 2011
Publication Date:
27 September 2011 (online)

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Abstract

A facile and highly efficient copper- and palladium-free procedure for the one-pot synthesis of ynones via coupling of sodium carboxylate salts with alkynes is described. In this method, cross-coupling of terminal alkynes with a mixture of structurally diverse sodium carboxylate salts, cyanuric chloride and triethylamine in the presence of magnesium chloride furnishes the corresponding ynones in good to excellent yields at room temperature.

Key words

one-pot synthesis - alkyne - cyanuric chloride - sodium carboxylate salt - ynone

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Similar reaction conditions were employed for carboxylic acid, except that Et3N (6.6 equiv) was employed

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General procedure for coupling of alkynes with sodium carboxylate salts using cyanuric chloride: To a solution of sodium carboxylate salt (3.3 mmol) in anhydrous MeCN (5 mL), was added TCT (1 mmol) and the reaction mixture was stirred at r.t. for 10 min. A solution of the appropriate alkyne (3 mmol), Et3N (3.3 mmol) and MgCl2 (3.3 mmol) in anhydrous MeCN (5 mL) was added and the solution was stirred for a further 50-110 min (until TLC indicated completion of the reaction, see Table  [5] ). The solution was filtered and the solvent was evaporated under vacuum. The remaining foam was then diluted in CHCl3 (50 mL) and subsequently washed with H2O (2 × 50 mL). The organic layer was dried (Na2SO4) and evaporated. The crude product was purified by short column chromatography on silica gel (n-hexane-EtOAc, 20:1).