An aerobic visible-light driven photoredox catalytic formation of 2-substituted benzothiazoles through radical cyclization of thioanilides has been accomplished. The reaction features C-H functionalization and C-S bond formation with no direct metal involvement except the sensitizer. The reaction highlights the following: (1) visible-light is the reaction driving force; (2) molecular oxygen is the terminal oxidant, and (3) water is the only byproduct.

Direct arylation of unactivated arenes or heteroarenes with aryl halides could be carried out in the presence of potassium tert-butoxide and dimethyl sulfoxide under visible-light irradiation. Ir(ppy)3 was found to be an effective photoredox catalyst for this reaction. The reactions of aryl iodides occurred at room temperature. Elevated temperature was required for aryl bromides. Homolytic aromatic substitution was proposed to be the operative reaction pathway.

The catalytic oxidation of alkenes to α-diketones is unprecedented. A new oxidation of alkenes, catalyzed by a ruthenium complex, which allows an efficient route to α-diketones using TBHP as an oxidant is described. This methodology is highly functional group tolerant, is practically convenient, requires no additional ligand, and operates under mild conditions with short reaction times. Based upon experimental observations, a plausible mechanism is proposed.

The synthesis of 2-substituted benzothiazoles has been achieved via cyclization of o-iodothiobenzanilide derivatives using Pd/C as the catalyst at room temperature. The protocol is ligand-free, additive-free, and high-yielding and involves very mild conditions.