Erstes Beispiel einer H-Verschiebung in ‘Thiocarbonyl-aminiden’ (N-(Alkylidensulfonio)aminiden)

First Example of an H-Shift in ‘Thiocarbonyl Aminides’ (N-(Alkylidenesulfonio)aminides) Reaction of benzyl azide ( 15a ) with the sterically hindered C?S group of 4,4-dimethyl-1,3-thiazole-5(4H)-thiones 14 (Scheme 3) and 1,1,3,3-tetramethylindane-2-thione ( 17 , Scheme 4) at 80° leads to the corresponding imines in high yield, without formation of any by-product. In contrast, 15a and 2,2,4,4-tetramethyl-3-thioxocyclobutanone ( 7 ) under the same conditions yielded, in addition to imine 19 , products 20a and 21 (Scheme 5). For the formation of 20a , a reaction mechanism via 1,4]-H shift in the intermediate ‘thiocarbonyl aminides’ 23 is proposed (Scheme 6). Product 21 as well as the dithiazole derivative 22 , which is formed only in the reaction with 4-nitrobenzyl azide ( 15c ), are formal adducts of the dipole 23 . Whereas precedents are known for the formation of cycloadducts of type 22 , the pathway to 21 is not known. Two possible mechanisms of its formation are proposed in Schemes 8 and 9.