Indirect Electroreduction of α,β-Epoxy and α,α-Dihalo Carbonyl Compounds with Diphenyl Diselenide or Ditelluride as a Recyclable Mediator

Abstract

Organoselenium and -tellurium compounds show rich redox properties at relatively low potential values. In particular, anionic species are useful when employed as recyclable reagents in an indirect electrolysis system, because they seem to be soft nucleophiles toward a variety of organic molecules. In the initial step of the recycle system, diphenyl diselenide may be reduced to a phenylselenide anion at the cathode. The mediated method provided better results than the direct one in terms of yield and product selectivity. The recycling method, however, was affected by a steric constraint of the alkyl substituents on oxirane ring. Turnover values of these reagents reach about 40; selenium or tellurium reagent can be recovered quantitatively as diselenide or ditelluride; the reaction proceeds in a selective fashion and can be applied to poly-functionalized molecules under mild conditions.