Phenyl or m-tolyl selenoamides reacted with functionalized α-haloacetic acid in 1∶1 or 1∶2 molar ratio with no catalyst in various alcohols to undergo a selenium transfer reaction. This reaction in dif-ferent molar ratios furnished the same C—Se—Se—C coupling products with a special structure bis(alkoxycarbonylmethyl) diselenide. A new and facile method for synthesis of such bis(alkoxycarbonyl-methyl) diselenides with the advantages of mild reaction conditions, high yields, easy availability of starting materials and good chemical selectivity was provided. In order to investigate the mechanism for this reac-tion, methyl α-bromoacetate or ethyl α-bromoacetate as starting material was added to the solution of phenyl selenoamide in ethanol in 1∶1 or 2∶1 molar ratio under the neutral condition at room temperature. The results indicated that the same product bis(methoxycarbonylmethyl) or bis(ethoxycarbonylmethyl) diselenide was formed. Byproduct ethyl benzoate was also separated. A mechanism for this C—Se—Se—C coupling reaction was proposed.

Key words: phenyl or m-tolyl selenoamide, α-haloacetic acid, diselenide, selenium transfer reaction