Iodonium Ion-Catalyzed Domino Synthesis of Z-Selective α,β-Diphenylthio Enones from Easily Accessible Secondary Alcohols.

The application of stabilized iodonium ions in organic synthesis remains largely unexplored. Herein, a metal-free domino synthesis of Z-selective α,β-diphenylthio enones is developed from easily available benzylic secondary alcohols employing thiophenol-stabilized iodonium ion as a catalyst. This methodology was further extended to five-membered and six-membered cyclic secondary alcohols. The UV-vis experiments suggest the formation of thiol-coordinated iodine(I) intermediates. Several control experiments establish that the reaction proceeds via the oxidation of alcohol to ketone, α-thiolation of ketones followed by α,β-unsaturation, and finally the β-thiolation of α,β-unsaturated ketones to generate bis-vinyl sulfides. The in situ-generated stabilized iodonium ion is highly efficient to catalyze multiple functional group transformations in a domino manner.