Stereoselective synthesis of 2-alkenylaziridines and 2-alkenylazetidines by palladium-catalyzed intramolecular amination of alpha- and beta-amino allenes

Whereas palladium-catalyzed reaction of N-arylsulfonyl-alpha -amino allenes with an aryl iodide (4 equiv) in the presence of potassium carbonate (4 eq uiv) in DMF at around 70 degreesC affords the corresponding 3-pyrroline der ivatives, the reaction in refluxing 1,4-dioxane under otherwise identical c onditions yields exclusively or most predominantly the corresponding 2-alke nylaziridines bearing an aryl group on the double bond. Similarly, N-arylsu lfonyl-beta -amino allenes can be also cyclized into the corresponding alke nylazetidines bearing a 2,4-cis-configuration under palladium-catalyzed cyc lization conditions in DMF.