ABSTRACT We report the first uses of a copper carbene–metal‐amido complex, Cu(IPr)(Cbz) ( 1 ), as an efficient photosensitizer for a broad range of triplet–triplet energy transfer (TTEnT) catalytic processes. Mechanistic studies confirm a triplet–triplet energy‐transfer pathway. These findings establish 1 as the first copper‐based photosensitizer competent in intermolecular 2+2 cycloaddition involving substrates with E T > 62 kcal/mol and hydrogen atom transfer via EnT, offering a cost‐effective, sustainable alternative to noble‐metal photocatalysts.
Ruggiero et al. (Mon,) studied this question.