Photoredox/Cobalt Dual Catalysis Enabled Regiospecific Synthesis of Distally Unsaturated Ketones with Hydrogen Evolution

In this report, we present a photoredox/cobalt dual catalytic system for the synthesis of distally unsaturated ketones. Upon a cooperative utilization of an organo photoredox catalyst and a cobaloxime catalyst, sequential ring-opening C-C bond scission and dehydrogenation of nonstrained tertiary cycloalkanols of variable ring sizes are achieved under visible-light irradiation, producing a wide range of gamma,delta-, delta,epsilon-, and even more distally unsaturated ketones in good yields, with hydrogen gas as the sole byproduct. The produced distally unsaturated ketones are versatile building blocks, which can be easily converted to other valuable molecules.

Automated summary

In this report, a photoredox/cobalt dual catalytic system was developed for the synthesis of distally unsaturated ketones. By using an organo photoredox catalyst and a cobaloxime catalyst in cooperation, sequential ring-opening C-C bond scission and dehydrogenation of nonstrained tertiary cycloalkanols of various ring sizes were achieved under visible-light irradiation, resulting in a wide range of distally unsaturated ketones with good yields and hydrogen gas as the only byproduct. The produced distally unsaturated ketones are versatile building blocks that can be easily converted to other valuable molecules.