An electrochemical approach for the synthesis of seven-membered cyclic ethers through 7-endo-dig selenocyclization of propargylic benzyl ethers has been developed. The reactions are carried out at room temperature by employing diselenides as selenylation reagents, demonstrating good substrate suitability and functional group compatibility. Various 7-membered cyclic ethers are obtained with good regioselectivity and yields under metal-reagent-free and oxidant-free conditions. The utility of the reaction is further highlighted by gram-scale synthesis and diverse product transformations.
Wu et al. (Wed,) studied this question.