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The use of gem‐difluorinated cyclopropanes (gem‐DFCPs) as fluoroallyl surrogates under transition‐metal catalysis has drawn considerable attention recently but such reactions are restricted to producing achiral or racemic mono‐fluoroalkenes. Herein, we report the first enantioselective allylation of indoles under rhodium catalysis with gem‐DFCPs. This reaction shows exceptional branched regioselectivity towards rhodium catalysis with gem‐DFCPs, which provides an efficient route to enantioenriched fluoroallylated indoles with wide substrate scope and good functional group tolerance. [ABSTRACT FROM AUTHOR]

Transition-metal catalyzed allylic substitution reactions of alkenes are among the most efficient methods for synthesizing diene compounds, driven by the inherent preference for an inner-sphere mechanism. Here, we present a demonstration of an outer-sphere mechanism in Rh-catalyzed allylic substitution reaction of simple alkenes using gem-difluorinated cyclopropanes as allyl surrogates. This unconventional mechanism offers an opportunity for the fluorine recycling of gem-difluorinated cyclopropanes via C − F bond cleavage/reformation, ultimately delivering allylic carbofluorination products. The developed method tolerates a wide range of simple alkenes, providing access to secondary, tertiary fluorides and gem-difluorides with 100% atom economy. DFT calculations reveal that the C − C bond formation goes through an unusual outer-sphere nucleophilic substitution of the alkenes to the allyl-Rh species instead of migration insertion, and the generated carbon cation then forms the C − F bond with tetrafluoroborate as a fluoride shuttle. Allylic substitution reaction of alkenes has been well-developed, but it has limitations, partly due to the intrinsic predilection for an inner-sphere mechanism. Herein, the authors present an outer-sphere mechanism in Rh-catalyzed allylic substitution reaction of simple alkenes using gem-difluorinated cyclopropanes as allyl surrogates. [ABSTRACT FROM AUTHOR]