Solution and Flash Vacuum Pyrolyses of 3-Arylpropanesulfonyl and 2-(Aryloxy)ethanesulfonyl Azides. Synthesis of 7-Membered Sultams

Article abstract of DOI:10.1021/jo00191a014

The solution and flash vacuum pyrolyses of 3-arylpropanesulfonyl azides have been studied and the results compared with those of the corresponding 2-arylethanesulfonyl azides.The best yields of 7-membered ring sultams are formed on solution decomposition in Freon 113.Hydrogen abstraction and solvent insertion products are obtained mainly in hydrocarbon solvents.The structure of the 7-membered sultams have been established unambiguously and an authentic sample of the parent 2,3,4,5-tetrahydro-1,2-thiazepine 1,1-dioxide prepared.Decomposition of 3-(2,6-dichlorophenyl)propanesulfonyl azide (22) leads to a 6,9-dichloro sultam (33c) via a 1,2-chlorine shift.FVP of 3-(2-mesityl)propanesulfonyl azide (20) gave a good yield of the 7-membered ring sultam (34)(1,2-methyl shift).FVP of 3-phenyl-1-propanesulfonyl azide (16) at 995 deg C (0.05 mm) gave, among other products, a 6.2percent yield of 5,6,7,8-tetrahydroquinoline (39).The formation of these products is discussed.Thermolysis of 2-(aryloxy)ethanesulfonyl azides gave the corresponding 7-membered ring sultams 27 as well.