Selenophilicity of copper in selenium-carbon bond formation from selenous acid using Cu(II)/Sn(II) reagent

Abstract

A selenium transfer reaction from selenous acid to benzyl and alkyl halides is initiated in the presence of stannous chloride and a catalytic amount of cupric chloride resulting in the formation of the corresponding diorganoselenides and/or diorganodiselenides as the major products as indicated by ¹H, ¹³C, ⁷⁷Se NMR, and MS. The reaction is characterized by a dual-metal effect at the selenium activation and transfer step. Thus, initial reaction of stannous chloride, cupric chloride, and selenous acid gives rise to α-Cu₂Se. Selenium transfer from the latter to the organic halide takes place with additional assistance of stannous chloride.