Diphenyl Diselenide-Assisted Radical Addition Reaction of Diphenyl Disulfide to Unsaturated Bonds upon Photoirradiation

Abstract

The addition reaction of interelement compounds with heteroatom–heteroatom single bonds to unsaturated bonds under photoirradiation is an important method for the efficient and atom-economical construction of carbon–heteroatom bonds. However, in practice, the desired addition reaction is sometimes unable to proceed as expected due to the low efficiency of the desired addition reactions or the preferential polymerization of unsaturated compounds. In this study, by combining an interelement compound with homologous heteroatom compounds as a catalyst, we succeeded in suppressing the polymerization of the unsaturated compounds and in attaining a highly selective carbon–heteroatom bond formation through the desired addition reaction. In this paper, we have examined in detail whether such a “catalytic radical reaction” proceeds for unsaturated compounds and found that the dithiolation of some unsaturated compounds (i.e., vinylic ethers, styrenes, and isocyanides) could proceed with the assistance of (PhSe)2 under light. The developed methods in this study are expected to have strong implications in the fields of radical chemistry, heteroatom chemistry, synthetic organic chemistry, and catalyst chemistry as atom-economical methods for carbon–heteroatom bond formation.

Recent advances in the dichalcogenation reactions of unsaturated compounds via double functionalization

“…More recently, Ogawa and coworkers disclosed a (PhSe) 2 -catalyzed 1,1-bis-thiolation of isocyanides 8a with diphenyl disulfide under photoirradiation (Scheme 8). 23 The products 8b were obtained in moderate to good yields with excellent selectivity. The reaction involves a thioselenation intermediate (PhS–C(N–R)–SePh) which could easily undergo thiyl radical addition followed by selenium radical elimination to produce the desired 1,1-dithiolation product.…”

“…The progress of radical thioselenation, thiotelluration, and selenotelluration of diverse unsaturated compounds, which is assisted by dichalcogenide binary systems under light irradiation, has been described by Dénès and Ogawa's group. 6 a ,23,65 In addition to these reports, there are another two examples of Rh-catalyzed or n BuLi-mediated synthesis of vinylic selenosulfides. 66 However, these methods generally suffer from narrow substrate scope, harsh reaction conditions and poor chemo-, regio- or stereoselectivity.…”