[2,3] Sigmatropic Rearrangement of Unstable Sulfur Ylides from Allyl Sulfonium Salts. Comparative Study of Electrochemical Reduction with the Base Method and Mechanism Elucidation by the MO Method

Abstract

Abstract The cathodic reduction of sulfonium salts in acetonirile under the presence and absence of benzaldehyde were carried out and compared with the results of the base method. Under the presence of benzaldehyde, the electrochemical reduction gave epoxides as a result of a Corey–Chaykovsky reaction confirming ylide formation. The electrochemical reduction of sulfonium salt without benzaldehyde yields the same [2,3] sigmatropic rearrangement product as those obtained by the base method, in high yield. The reaction mechanism was studied by semi-emprical MO methods.