B 12 -Catalyzed Carbonylation of Carbon Tetrahalides: Using a Broad Range of Visible Light to Access Diverse Carbonyl Compounds.

Visible-light-driven organic synthesis is a green and sustainable method for producing fine chemicals and is highly desirable at both laboratory and industrial scales. In this study, we developed a broad-range (including the red region) visible-light-driven carbonylation of CCl ₄ , CBr ₄ , and CBr ₃ F with nucleophiles, such as amines and alcohols, using a B ₁₂ -Mg ²⁺ /TiO ₂ hybrid catalyst. Carbonyl molecules such as ureas, carbamates, carbonate esters, and carbamoyl fluorides were synthesized with high selectivity and efficiency under mild conditions. Diffuse reflectance UV-vis spectroscopy, femtosecond time-resolved diffuse reflectance spectroscopy, and density functional theory calculations revealed the reaction mechanism is a combination of S _N 2 and single-electron transfer. This is a rare example of a low-energy, red-light-driven photocatalysis, which has been a highly desired organic reaction in recent years. We believe that this study provides a general platform to access diverse carbonyl molecules and could promote photocatalytic carbonylation reactions on a pilot scale.
(© 2024 The Author(s). Chemistry - A European Journal published by Wiley-VCH GmbH.)