Probing Intramolecular Electron Transfer in Redox Tag Processes

Herein, we show that redox tag-guided intermolecular formal [2 + 2] cycloaddition can be used as a probe to investigate intramolecular single-electron transfer (SET) mechanisms. The efficacy of intramolecular SET can be evaluated in association with concomitant carbon–carbon bond formation and/or cleavage, leading to cycloaddition or cross-metathesis. Experimental and theoretical results suggest that the intramolecular SET is under both thermodynamic and kinetic control and can also occur through bonds, not only through space.