Mechanism of the Dehydrogenative Phenothiazination of Phenols.

The straightforward capture of oxidized phenothiazines with phenols under aerobic conditions represents a unique cross-dehydrogenative C-N bond-forming reaction in terms of operational simplicity. The mechanism of this cross-dehydrogenative N-arylation of phenothiazines with phenols has been the object of debate, particularly regarding the order in which the substrates are oxidized and their potentially radical or cationic nature. Understanding the selective reactivity of phenols for oxidized phenothiazines is one of the key objectives of this study.