1,3-Bis(4-methylbenzyl)imidazol-2-ylidene silver(I) chloride catalyzed carboxylative coupling of terminal alkynes, butyl iodide and carbon dioxide

The N-heterocyclic carbene silver(I) complex 1,3-bis(4-methylbenzyl)imidazol-2-ylidene silver chloride was applied as the effective catalyst for the three-component carboxylative coupling of terminal alkynes, butyl iodide and carbon dioxide. The reaction proved to be highly efficient when using 2 mol% of 1,3-bis(4-methylbenzyl)imidazol-2-ylidene silver(I) chloride as the catalyst in the presence of 1.5 equiv. of Cs2CO3 as the base in DMF. This reaction shows good selectivity and substituent-loading capability, in which various functionalized 2-alkynoates were obtained in good yields under very mild conditions.