Thiol-Promoted Selective Addition of Aldehydes to Ketones

Doron Pappo, Chemistry, Ben-Gurion University, Beer Sheva, Israel

A simple and efficient thiol-mediated addition of aromatic and aliphatic aldehydes to ketones was developed.

This thermodynamically controlled Pummerer/aldol addition reaction, which can tolerate both moisture and protic functionalities, provide a direct entry to syn-beta-ketosulfides in high chemo and regioselectivity.

Mechanistic study revealed that selective transformation of the aldehyde to an electrophilic thionium ion species concurrent with the generation of nucleophilic vinyl sulfide coupling partner from the ketone are imposing cross coupling over dimerization.