The Z-enoate Assisted Meyer-Schuster Rearrangement with Thiol Nucleophiles. An Approach for the Functionalized Vinyl Sulfides, and Sulfones.

Vinyl sulfides and their sulfones act as very important building blocks in organic synthesis. Further they are prevalent in bioactive natural and unnatural products and exhibit diverse bioactivities. Here in we report a Z-enoate assisted Meyer-Schuster rearrangement approach for the rapid generation of 1,4-ketoester based vinyl sulfides. The thiols were employed as nucleophiles during this versatile transformation the propargylic alcohols. The process exhibited broader scope for thiols (aryl and alkyl), and propargylic alcohols. Further these vinyl sulfides were efficiently converted into the corresponding vinyl sulfones by employing a Mo-based oxidizing agent. Sodium borohydride reduction of the 1,4-ketoester based vinyl sulfides directly gave the butyrolactones having the vinyl sulfide unit. The phenols, alcohols and amines were found to be inefficient as nucleophiles to give the corresponding vinyl ethers.