Light-Controlled Biocatalysis by Unspecific Peroxygenases with Genetically Encoded Photosensitizers.

Fungal unspecific peroxygenases (UPOs) have gained substantial attention for their versatile oxyfunctionalization chemistry paired with impressive catalytic capabilities. A major drawback, however, remains their sensitivity towards their co-substrate hydrogen peroxide, necessitating the use of smart in situ hydrogen peroxide generation methods to enable efficient catalysis setups. Herein, we introduce flavin-containing protein photosensitizers as a new general tool for light-controlled in situ hydrogen peroxide production.

General cross-coupling reactions with adaptive dynamic homogeneous catalysis.

Cross-coupling reactions are among the most important transformations in modern organic synthesis. Although the range of reported (het)aryl halides and nucleophile coupling partners is very large considering various protocols, the reaction conditions vary considerably between compound classes, necessitating renewed case-by-case optimization of the reaction conditions. Here we introduce adaptive dynamic homogeneous catalysis (AD-HoC) with nickel under visible-light-driven redox reaction conditions for general C(sp)-(hetero)atom coupling reactions.

Synthetic Molecular Photoelectrochemistry: New Frontiers in Synthetic Applications, Mechanistic Insights and Scalability.

Synthetic photoelectrochemistry (PEC) is receiving increasing attention as a new frontier for the generation and handling of reactive intermediates. PEC permits selective single-electron transfer (SET) reactions in a much greener way and broadens the redox window of possible transformations. Herein, the most recent contributions are reviewed, demonstrating exciting new opportunities, namely, the combination of PEC with other reactivity paradigms (hydrogen-atom transfer, radical polar crossover, energy transfer sensitization), scalability up to multigram scale, novel selectivities in SET super-oxidations/reductions and the importance of precomplexation to temporally enable excited radical ion catalysis.

Photocatalytic C-H Trifluoromethylthiolation by the Decatungstate Anion.

A broadly applicable method for the trifluoromethylthiolation of methylene C(sp)-H, methine C(sp)-H, α-oxygen C(sp)-H, and formyl C(sp)-H bonds is presented using the decatungstate anion as the sole catalyst. By adjusting the substrate ratio and reaction concentration, this method was applied to 40 examples in good regioselectivities, including the derivatization of natural products. Furthermore, SCF-drug analogues were synthesized by subsequent functionalization of the SCF products, highlighting the importance of this photocatalyzed C-H functionalization.

Electro-mediated PhotoRedox Catalysis for Selective C(sp )-O Cleavages of Phosphinated Alcohols to Carbanions.

We report a novel example of electro-mediated photoredox catalysis (e-PRC) in the reductive cleavage of C(sp )-O bonds of phosphinated alcohols to alkyl carbanions. As well as deoxygenations, olefinations are reported which are E-selective and can be made Z-selective in a tandem reduction/photosensitization process where both steps are photoelectrochemically promoted. Spectroscopy, computation, and catalyst structural variations reveal that our new naphthalene monoimide-type catalyst allows for an intimate dispersive precomplexation of its radical anion form with the phosphinate substrate, facilitating a reactivity-determining C(sp )-O cleavage.

Visible light induced redox neutral fragmentation of 1,2-diol derivatives.

A homogeneous, redox-neutral photo fragmentation of diol derivatives was developed. Under photo/hydrogen atom transfer (HAT) dual catalysis, diol derivatives such as lignin model compounds and diol monoesters undergo selective β C(sp3)-O bond cleavage to afford ketones, phenols and acids effectively.