Harnessing visible light to access excited (triplet) states of organic compounds can enable impressive reactivity modes. This tutorial review covers the photophysical fundamentals and most significant advances in the field of visible-light-mediated energy transfer catalysis within the last decade. Methods to determine excited triplet state energies and to characterize the underlying Dexter energy transfer are discussed. Synthetic applications of this field, divided into four main categories (cyclization reactions, double bond isomerizations, bond dissociations and sensitization of metal complexes), are also examined.

As ystematic,u ser-friendly assessment tool that delivers ac lear overview of the sensitivity of reactions to key parameters is highly desirable.Herein, the development of such amethod is described. The intuitive,standardized presentation of the results in ar adar diagram enables the sensitivity of ap rotocol to be rapidly assessed. This method was applied to five different visible-light-mediated photochemical reactions, and the results were correlated to the underlying mechanism. Ultimately,webelieve that this assessment will help to increase the uptake of new synthetic methods and their reproducibility. Angewandte Chemie Communications

The concept of reductive radical-polar crossover (RRPCO) reactions has recently emerged as a valuable and powerful tool to overcome limitations of both radical and traditional polar chemistry.