Visible-Light-Driven Photocatalytic Kharasch-Type Addition of 1,6-Enynes
Fang-Zhou Geng, Shichao Wang, Kexian Song, Wen‐Juan Hao, Bo Jiang
Abstract
A new visible-light-driven photocatalytic Kharasch-type addition of 1,6-enynes was reported. By using the characteristics of the in-situ-generation of trihalomethyl radicals from photocatalytic reduction of trichloromethane bromide and carbon tetrabromide, fac-Ir(ppy)3-catalyzed Kharasch-type addition of 1,6-enynes of these polyhalogenated hydrocarbon substrates at room temperature was conducted under visible-light irradiation, regioselectively affording 1-indanone derivatives with an exocyclic double bond and a quaternary carbon in moderate to good yields. Based on the experimental results and literature reports, a reasonable reaction mechanism was proposed, which involved the in-situ-generation of trihalomethyl radicals, radical-induced addition-cyclization and radical cross coupling. In addition, this protocol featured wide substrate scope, high functional group compatibility, 100% atomic utilization, and mild conditions as well as simple operation. It provides a green, mild, and efficient synthetic strategy for the construction of 1-indanone skeleton with potential application, which is consistent with the concept of green chemistry.