Diphenyl Diselenide as a Useful Reagent for Intermolecular Domino Reactions of Various Unsaturated Compounds under Photoirradiation Conditions

Abstract

Abstract This paper describes full details of a series of intermolecular domino reactions mediated by diphenyl diselenide (PhSeSePh). Diphenyl diselenide, which has just the right strength of carbon radical capturing ability, can be employed as a useful mediator for intermolecular domino reactions of unsaturated compounds. Upon irradiation through Pyrex with a tungsten lamp (hv > 300 nm), a sequential addition of diphenyl diselenide to alkynes bearing an electron-withdrawing group and alkenes bearing an electron-donating group proceeds successfully to provide the corresponding intermolecular three-component coupling products in high yields. In place of alkenes, the use of isocyanides leads to the formation of the corresponding three-component coupling products of alkynes, isocyanides, and (PhSe)2, selectively. Moreover, when two kinds of alkenes (i.e., electron-rich alkenes and electron-poor alkenes) are used in this photoinduced alkyne-(PhSe)2 reaction system, a novel domino reaction of diphenyl diselenide with an alkyne and two kinds of alkenes, followed by 5-exo radical cyclization, takes place sequentially to provide the corresponding cyclic four-component coupling products in good yields.