Synthesis of Fluorinated Spiroindolenines by Transition Metal‐Catalyzed Indole Dearomatizations

Abstract A strategy to access fluorinated spiroindolenines has been developed, involving a selective functionalization of indoles with fluorinated moieties and subsequent catalytic dearomatization. Trifluomethylthio (SCF 3 ), diethyl phosphono(difluoromethyl)thio (SCF 2 P(O)(OEt) 2 ) and (phenylsulfonyl)difluoromethyl (CF 2 SO 2 Ph) groups were embedded at the C2 position of indole derivatives substituted with alkynes, allenes, and allyl carbonate moieties at the C3 position. A gold‐catalyzed cycloisomerization gave access to five spiroindolenines, and an enantioselective palladium catalyzed cyclization provided 10 fluorinated spirocyclic products with up to 77% ee.