Fe-Catalyzed Stereospecific Intramolecular Friedel-Crafts-type Reaction of Fluoroalkyl Cyclopropyl Carbinols via Non-classical Carbocation

Here we describe a Fe-catalyzed stereospecific intramolecular Friedel-Crafts-type reaction of polysubstituted stereodefined fluoroalkyl cyclopropyl carbinols. This transformation provides access to a series of fluoroalkyl group-substituted dihydro-1H-indenols bearing three continuous stereogenic centers including two congested tetra-substituted stereocenters. The key to the realization of this reaction relies on the electronic destabilizing effect of fluoroalkyl group to tune the stability and reactivity of non-classical cyclopropyl-carbinyl cation intermediate. Functional group interconversions of the obtained diastereomerically pure dihydro-1H-indenols further demonstrated the synthetic utility of this rationally designed reaction.