Isotope effects as mechanistic probes in solution and in intrazeolite photooxygenations. The formation of a hydroperoxysulfonium ylide.
The reactions of singlet oxygen with 2,2,6,6-tetradeuterio-1,4-dithiane have been examined in acetone and methanol, and in the interior of the zeolite NaY. The product isotope effects k(H)/k(D) have been measured for sulfoxide and, when possible, for sulfone formation. The results provide evidence for a hydroperoxysulfonium ylide intermediate in acetone, a hydrogen bonded or sulfurane intermediate in methanol, and an interesting equilibrium between two complexed forms of the substrate in NaY.
Clennan
Edward L
EL
Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, USA. clennane@uwyo.edu
Pan
Gui-Lan
GL