Photochemical and electrochemical regioselective cross-dehydrogenative C(sp2)–H sulfenylation and selenylation of substituted benzo[a]phenazin-5-ols

Abstract

A dual synthetic strategy based on visible-light (white LEDs/direct sunlight) irradiation and electrosynthesis has been explored for the regioselective cross-dehydrogenative C(sp²)–H sulfenylation and selenylation of substituted benzo[a]phenazin-5-ols in an oxygen atmosphere under mild reaction conditions. The photochemical process does not require any external photoredox catalysts. Photocatalytic application of in situ generated deprotonated species of benzo[a]phenazin-5-ol molecules has also been accomplished. This is the first report on the synthesis of functionalized phenazine derivatives.