A Modular Olefination of Aldehydes with Thiols as Coupling Partners

Olefins range amongst the most important motifs in organic chemistry. Hence, the development of novel olefin syntheses has remained a constant field of research in synthetic chemistry to date. Herein, we report the development of a modular olefination that converts aldehydes into olefins with thiols as reaction partners. The simple, transition metal-free protocol proceeds via an unsymmetrical bissulfone intermediate which is converted into the respective alkene in a Ramberg-Backlund-type process. Differently substituted olefins can be synthesized from readily available starting materials in typically good yields and stereoselectivities using basic laboratory chemicals exclusively. Complementary reaction conditions differing in the choice of solvent favor the E/Z-products respectively under kinetic control rendering this protocol an interesting economical addition to the family of olefin syntheses.

Automated summary

We report a novel method for the synthesis of olefins from aldehydes and thiols. The process involves the conversion of an unsymmetrical bissulfone intermediate into the corresponding alkene via a transition metal-free protocol. Differently substituted olefins can be synthesized in good yields and with stereoselectivity using basic laboratory chemicals. The choice of solvent determines the kinetic control for the formation of E/Z-products, making this method an interesting addition to olefin syntheses.