N-Sulfonylamines are generated and in situ reacted with 3-dialkylamino-2H-azirines to give N-sulfamoyl-acrylamidines. The magneticnonequivalence of prochiral groups in the 1H NMR spectrum suggests an axially chiral structure, which is supported by density-functional theory calculations. Base-induced cyclization occurs readily to give 1,2,6-thiadiazine derivatives.
The title compounds react to give [2:1] cycloadducts with a dithiatriazine structure. However, the least sterically hindered sulfonylamine and a 3,4-dihydroisoquinoline react in a highly unusual [4+4] cycloaddition.