Model compounds of Δ4, 5-, Δ5, 6-, and Δ6, 7-alkenylnitrosamines were synthesized and photolyzed to generate the corresponding alkenylaminium radicals. The Δ5, 6- alkenylaminium radicals underwent efficient intramolecular addition leading to the exclusive formation of pyrrolidine derivatives, the yield of which was lower if the steric strain and hindrance were severe in the cyclization transition state. The Δ6, 7-alkenylaminium radical ...
