Reaction of dialkyldisulfides or diselenides with allenes is catalyzed by a rhodium-phosphine complex and trifluoromethanesulfonic acid giving (E)-2-alkylthio(seleno)-1,3-dienes and (E)-2-alkylthio(seleno)-2-alkenes. Unlike the reaction of alkynes, the reaction of allene is accompanied by hydridetransfer.
undergo an exchange reaction. The reactions of diaryl disulfides and dialkyl disulfides are even faster, and reach equilibrium within 5 min at room temperature in the presence of the rhodium complex and 1,2-bis(diphenylphosphino)ethane (dppe). This exchange reaction is considerably affected by the substituents on the disulfides. Treatment of diphenyl disulfide, di(p-tolyl) disulfide, and bis(sec-butyl) disulfide
Opticallyactive alkyl aryl selenoxides were synthesized by the asymmetricoxidation of corresponding selenides under Sharpless oxidation conditions. The absolute configurations of the opticallyactive alkyl aryl selenoxides prepared were estimated by comparisons of their circular dichroism spectra with those of the opticallyactivesulfoxides.