Kaolinite Powder Catalyzed Stereoselective Conversion of Dialkyl-2-(1,1,3-trioxo-1,3-dihydro-2H-1,2-benzisothiazol- 2-yl)-3-(triphenylphosphoranylidene)succinates to Dialkyl- 2-(1,1,3-trioxo-1,3-dihydro-2H-1,2-benzisothiazol-2-yl)-2- butendioat

Abstract

Protonation of the highly reactive 1:1 intermediates produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates by saccharin leads to vinyltriphenyl-phosphonium salts, which undergo an addition reaction with counter anion in CH₂Cl₂ at room temperature to produce corresponding stabilized phosphorus ylides. Kaolinite powder was found to catalyze conversion of the stabilized phosphorus ylides to corresponding electron-poor N-vinylated isothiazoles in solvent-free conditions at 100ºC in 1 h in fairly good yields.