Triarylamines are demonstrated as novel, tunable electroactivated photocatalysts that use dispersion precomplexation to harness the full potential of the visible photon (>4.0 V vs. SCE) in anti-Kasha photo(electro)chemical super-oxidations of arenes.

C-alkylations of alkali metal carbanions with olefins, first reported five decades ago, is a class of reaction undergoing a resurgence in organic synthesis in recent years. As opposed to expectations...

A highly efficient and enantioselective asymmetric hydrogenation catalyzed by Ru-DTBM-segphos is reported for a broad range of pyridine−pyrroline trisubstituted alkenes. Kinetic, spectroscopic, and computational studies suggest that addition of H 2 is rate-determining, alkene insertion is enantio-determining, and that the presence and position of the pyridine nitrogen is critical to enantioselectivity. These studies also reveal an intriguing Ru-catalyzed H/D exchange process that is facilitated by a substrate at room temperature and low pressure, where hydrogenation activity is suppressed. These studies lead to a mechanistic proposal that further defines the roles of hydrogen gas, Ru−H species, and protic solvents in this catalytic system.

Electron‐deficient acridones and in situ generated acridinium salts are reported potent, closed‐shell photooxidants that undergo surprising mechanisms. When bridging acyclic triarylamine catalysts with a carbonyl group (acridones), this completely diverts their behavior away from open‐shell, radical cationic, ‘beyond diffusion’ photocatalysis to closed‐shell, neutral, diffusion‐controlled photocatalysis. Brønsted acid activation of acridones dramatically increases excited state oxidation power (by +0.8 V). Upon reduction of protonated acridones, they transform to electron‐deficient acridinium salts as even more potent photooxidants (*E1/2 = +2.56‐3.05 V vs SCE). These oxidize even electron‐deficient arenes where conventional acridinium salt photooxidants have thusfar been limited to electron‐rich arenes. Surprisingly, upon photoexcitation these electron‐deficient acridinium salts appear to undergo two electron reductive quenching to form spectroscopically‐detected acridinide anions. This new behaviour is partly enabled by a substrate assembly with the arene, and contrasts to conventional SET reductive quenching of acridinium salts. Critically, this study illustrates how redox active chromophoric molecules initially considered photocatalysts can transform during the reaction to catalytically active species with completely different redox and spectroscopic properties.