Photocatalytic polarity-reversed Corey-Chaykovsky cyclopropanation

Cyclopropanes are ubiquitous structural motifs in biologically active molecules and functional materials, yet their synthesis remains largely either dependent on carbene-based approaches or limited to activated electron deficient π-systems. Herein, we report a photocatalytic polarity-reversed Corey-Chaykovsky cyclopropanation that exploits the single electron oxidative activation of sulfoxonium ylides to generate electrophilic carbon-centered radicals to access cyclopropanes from electron rich alkenes following a radical-polar crossover process. This strategy enables the efficient, mild and selective synthesis of functionalized cyclopropanes from non-activated alkenes, while avoiding the use of hazardous diazo reagents. Beyond expanding the synthetic utility of sulfoxonium ylides in cyclopropane synthesis, this work establishes photocatalytic oxidative activation of sulfur ylides as a powerful platform for polarity-reversed C-C bond construction.