A method was developed for the direct dehydrogenative construction of CN bonds between unprotected phenols and a series of cyclic anilines without resorting to any kind of metal activation of either substrate and without the use of halides. The resulting process relies on the exclusively organic activation of molecular oxygen and the subsequent oxidation of the aniline substrate. This allows the coupling of ubiquitous phenols, thus furnishing aminophenols through an atom-economical and most sustainable dehydrogenative amination method. This new reactivity, which relies on the intrinsic organic reactivity of cumene in what can be seen as a modified Hock activation process of oxygen, is expected to have a large impact on the formation of CN bonds in organic synthesis.

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. The reaction mechanism is investigated in detail by utilizing electron paramagnetic resonance spectroscopy, cyclic voltammetry, radical trap experiments, kinetic isotope effects, and solvent effects. Finally, the key reaction steps are calculated by using density functional theory (DFT) and broken‐symmetry open‐shell singlet DFT methods to unravel a unique biradical mechanism for the oxidative phenothiazination of phenols.

What does it take to force a rigid and strained dehydrogenative ring closure, for example, in phenylcarbazoles? Since the works of Buchwald and Fagnou, palladium‐catalysed ring‐closing dehydrogenative reactions are legion, but will not operate when the strain at the reductive elimination stage becomes too large. We propose here a “muscled up” super‐oxidative palldium‐catalysed CH activation method for the ring closure of strained phenylcarbazoles.magnified image

[1] Einer der grçßten Vorteile der direkten aromatischen Funktionalisierung,o bn un durch elektrophilen Angriff [2]

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