Organocatalyzed Enantioselective Fluorocyclizations


  • We thank the European Union (PIEF-GA-2009-235510 to T.M., PIEF-GA-2008-220034 to O.L.), GSK (G.B.) and the Berrow Foundation for a scholarship to G.T.G. We also thank Dr. S. Fletcher for very helpful discussions.


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Enantioenriched fluorinated heterocycles can be prepared through fluorocyclizations of prochiral indoles (see scheme; Ts=tosyl, Bn=benzyl, Boc=tert-butoxycarbonyl). More than twenty examples for this cascade fluorination–cyclization, which is catalyzed by cinchona alkaloids and employs N-fluorobenzenesulfonimide as the electrophilic fluorine source have been explored, and an unprecedented catalytic asymmetric difluorocyclization has also been identified.