Mechanistic Studies on Propargyl Alcohol-Tethered Alkylidenecyclopropane with Aryldiazonium Salt Initiated by Visible Light

Main observation and conclusion This paper discloses the reaction mechanism of two consecutive but different visible light photo-induced chain processes for the rapid construction of spirobi[indene] skeletons. The first process is triggered by a photo-induced single-electron-transfer (SET) of an electron donor-accepter (EDA) complex. The second process is initiated by a direct SET process between aryldiazonium salt and the excited allenic intermediate. In these two processes, another SET took place respectively on the in situ formed radical intermediate to realize a redox-neutral outcome. The mechanistic studies have been carried out by control experiments, kinetic and spectroscopic analyses, deuterium labeling experiments to support these two chain processes. [GRAPHICS] .

Automated summary

This study reveals the reaction mechanisms of two consecutive visible light photo-induced chain processes, triggered by photo-induced single-electron transfer and direct SET processes respectively. These processes were supported by mechanistic studies and experiments to achieve a redox-neutral outcome.