Studies of heterocyclic analogues of azulenes. Part 9. Regioselective cycloadditions of 2H-cycloheptathiazol-2-one with acetylenic esters and electron-deficient olefins
Abstract
Cycloadditions of 2H-cycloheptathiazol-2-one with acetylenic esters and electron-deficient olefins have been found to proceed regioselectively, producing 2-oxo-3H-1-this-2a-azacyclopent[cd]azulenes by 1,10-dipolar cyclisation, and 2-oxo-3H-1-this-2a-azacyclopenta[ef]heptalenes.