Reaction of Vinyl Aziridines with Arynes: Synthesis of Benzazepines and Branched Allyl Fluorides.

We report the cycloaddition between vinyl aziridines and arynes. Depending on the reaction conditions and the choice of the aryne precursor, the aziridinium intermediate can be trapped through two distinct mechanistic pathways. The first one proceeds through a formal [5+2] cycloaddition to furnish valuable multi-substituted benzazepines. In the second pathway, the aziridinium is intercepted by a fluoride ion to afford allylic fluorides in good yields. Both reactions proceed stereospecifically and furnish enantiopure benzazepines and allylic fluorides.