Allene Cyclopropanation with Fluoroalkyl Carbenes.

[2 + 1] Cycloaddition is among the most widely studied strategies for building strained small-ring scaffolds in organic synthesis, yet the corresponding reaction involving substrates with cumulated unsaturated bonds poses a persistent challenge, due to the demand for concurrent regulation of chemo-, regio- and Z/E-selectivities across competing reactions. Herein, we report the first divergent allene cyclopropanation with fluoroalkyl carbenes derived from fluoroalkyl triftosylhydrazones under distinct catalyst systems. The protocol achieves formal regiodivergent cyclopropanation of allenes at either terminal or internal double bonds; cyclopropanation of allenes with difluoromethyl or trifluoromethyl carbenes; enantioselective cyclopropanation of allenes. Density functional theory calculations clarify the stereoselective and regioselective control mechanisms induced by divergent catalysts. Notably, this work delivers a diverse library of fluoroalkylated methylenecyclopropanes, alkylidenecyclopropanes and chiral analogues, creating new opportunities for organic synthesis and drug discovery.