Rearrangements of Unsaturated Sulphides

The Wittig rearrangement of allyl vinyl and benzyl vinyl ethers brought about by strong bases is not shown by benzyl vinyl sulphides. Base-catalysed rearrangement of bis(propargyl) sulphides involves first the formation of the 

Nakamura, N. Ogino, and T. Migita, Intemat. J. Sulfur Chem., 1973,8, 13. 

Examples of thio-Claisen rearrangements in the recent literature involve 3-substituted 4-allylthio-pyrimidin-2-ones, 2-propargylthiobenzimidazoles, and S-allylthiodimedones (25), which give (26) when AcjO is used as solvent, or 

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