Generation of aminyl radicals and use in the synthesis of nitrogen heterocycles

The purpose of this project was to show that aminyl radicals (nitrogen atoms with one unpaired electron) could be generated from the radical reactions between tri-n-butyltin hydride and sulfenamides. Sulfenamides are defined as a divalent sulfur atom bonded to a trivalent nitrogen atom. A wide range of sulfenamides were prepared in good yield using two methods. Benzenesulfenyl chloride and primary or secondary amines were reacted at room temperature with triethylamine as base to yield sulfenamides. Sulfenamides were also synthesised in good yield from the reaction between amines and N-(benzenesulfenyl)phthalimide. Initially, reactions were performed to show that aminyl radicals could be formed by reacting selected sulfenamides with tri-n-butyltin hydride in refluxing solvent. When these reactions proved to be successful, experiments were carried out to cyclise the intermediate aminyl radicals intramolecularly onto an olefin. The studies have led to a new method for the formation of nitrogen containing heterocycles. [Continues.]