Unusual reactions of N-allylic difluoroenamines under thermal conditions

N-Allylic difluoroenamines exhibited unusual behaviors under thermal conditions; N-allyl difluoroenamines in refluxing xylene afforded not only aza-Claisen rearrangement products, but also 2-azabicyclo2.1.1]hexanes, whose formation could be explained via intramolecular 2+2]-cycloaddition, whilst N-prenyl difluoroenamine underwent an ene reaction to give the pyrrolidine as a sole product.