電気陽性な典型元素の励起状態を利用する光反応の開発

Abstract

Photoinduced reactions have received much attention as a powerful tool to access kinetically or thermodynamically prohibited reactions on the ground state. However, these reactions have been developed mainly by using electro-negative elements such as C, O, N, halogens as well as transition-metals. On the other hand, we have revealed the nature of chemical species including electro-positive main-group elements, such as boron (B), silicon (Si), and tin (Sn), on the excited state, developing the highly reactive and selective photoinduced reactions. For diboron (B-B) reagents, we designed the anionic photo-absorbing borate complex to enable a quadruple borylation reaction of terminal alkynes under ultraviolet irradiation. For stannyl (Sn) species, we revealed that the illumination of stannyl anions generates the excited triplet stannyl diradicals, which showed the orthogonality to traditional reagents (cations, anions, and radicals) to enable hydrostannylation of alkynes and defluorostannylation of fluoroarenes. For silylborane (Si-B) reagents, we developed dearomative triple elementalization (carbo-silaboration) reactions of quinolines by the excitation of silyl-borate complexes without the need for any catalyst.