Photocatalyzed Annulation-Biselenylation of Enynone with Diarylselenides toward Biselenium-Substituted 1-Indanones under Metal- and Photosensitizer-Free Conditions

A practical photocatalytic annulation-biselenylation strategy has been developed for the efficient synthesis of biselenium-substituted 1-indanones (38 examples in total) with generally good yields (up to 95%) and excellent stereoselectivity (>19 : 1 Z/E ratio) by employing enynones and diaryl selenides as starting materials under photosensitizer-free conditions. The reaction mechanism involves a cascade process comprising homolytic cleavage, radical addition, 5-exo-dig cyclization, and radical capture, enabling sequential formation of multiple bonds, such as C(sp³)-Se, C(sp³)-C(sp²), and C(sp²)-Se bonds, to rapidly construct molecular complexity. Notably, this approach demonstrates wide substrate compatibility and excellent tolerability towards various functional groups. It is further characterized by its remarkable efficiency in creating chemical bonds and achieving high atomic utilization of 100%.