Convenient Syntheses of Benzo-Fluorinated Dibenz[b,f]azepines: Rearrangements of Isatins, Acridines, and Indoles

Efficient procedures for the synthesis of benzo-fluorinated dibenz[b,f]azepines (iminostilbenes) from fluorinated isatins or indoles using a number of ring-expansion reactions are described. A range of mono- and difluorinated analogues is accessible, and the syntheses can deliver gram quantities of the final products, which are precursors of fluoro analogues of the important anticonvulsant carbamazepine.