Photoinduced Synthesis of Bisphosphinated Quinoxalines via Radical Cyclization of <i>o</i>‐Diisocyanoarenes with Diphosphines
Yuki Yamamoto, Akiya Ogawa
Abstract
Abstract The cycloaddition reaction of o ‐diisocyanoarenes with interelement compounds under light is a very important reaction system to clarify whether this reaction proceeds by radical cyclization or by aza‐Bergman cyclization. In this study, a series of diphosphines with phosphorus‐phosphorus single bonds were selected as interelement compounds, and their cycloaddition reactions with o ‐diisocyanoarenes under light were investigated in detail to achieve a novel photoinduced synthesis of bisphosphinated quinoxalines via the radical cyclization pathway. In addition, the photoinduced reaction of diphosphines with isocyanides having o ‐functional groups such as cyano and ethenyl groups allowed us to elucidate the reaction pathway and product selectivity of this bisphosphination. Furthermore, the one‐pot synthesis of Pd II ‐quinoxaline complex was successfully achieved by applying the developed reaction.