An Investigation of the Intramolecular Ene Reaction of N-Acyl Imines

N-Acyl imines, produced by the flash vacuum thermolysis of hydroxamic acid derivatives, participate in the intramolecular ene reaction to give nitrogen heterocycles. The reaction is accelerated by carboxyl substitutents on the carbon atom of the N-acyl imine, and the reaction is more successful for the production of pyrrolidine rather than piperdine derivatives.