Regioselective Photoredox Catalyzed Cycloadditions of Acyclic Carbonyl Ylides.

A photoredox catalyzed [3 + 2] dipolar cycloaddition between acyclic carbonyl ylides generated from α-cyano epoxides and dipolarophiles is described. This method, influenced by anionic charge localization and temperature control, enabled the synthesis of regioselective functionalized cyclic ethers. By leveraging different dipolarophiles, Lewis acid mediated activation afforded either furan or hydroxy-dihydronaphthalene scaffolds. A direct synthesis of lignan natural products isodiphyllin and diphyllin is achieved by exploiting the nitrile's reactivity as a directing handle for the desired regioisomer.