Abstract
Sulfonylallenes, R - SO2 - CHCCH2 (R= 3 - vinyl - cyclohex - 2 - en - 1 - yl (1a) and 2 - methyl - 3 - vinylcyclohex - 2 - en - 1 - yl (1b) ) undergo thermally the [4+2] Diels - Alderand [2+2] two-step intramolecular cycloadditions, the latter predominating in 1b. Thebranching between the two types of cycloadditions has been studied in terms of the transitionstates calculated semiempirically.
