De‐Risking S‐F Bond Formation: A Gas Cylinder‐Free Strategy to Access S(IV) and S(VI) Fluorinated Compounds**
Reza Kordnezhadian, Armir Zogu, Carlotta Borgarelli, Ruben Van Lommel, Joachim Demaerel, Wim M. De Borggraeve, Ermal Ismalaj
Abstract
Abstract The sulfur‐fluorine partnership occupies a privileged position in fluorine chemistry given the functional versatility that it imparts to organic structures. Despite this, available methodologies to forge S−F bonds are limited compared to C−F bond formation. Here, we describe a synthetic protocol that selectively enables the oxidative halogenation of aliphatic, aromatic, and heteroaromatic thiols to their corresponding SF 4 Cl, SO 2 F and SF 3 derivatives. Selective oxidation of thiols to either S(IV)‐F or S(VI)‐F compounds is achieved by employing bench‐stable calcium hypochlorite as chlorine surrogate (CLOgen), in the presence of KF as fluoride source. Density functional theory (DFT) calculations provided insight into the mechanistic aspects of the transformation and rationalized the observed isomeric preference towards the SF 4 Cl derivatives. Ultimately, this glovebox‐free method selectively dispatches three classes of compounds upon reaction condition fine‐tuning. Furthermore, first‐in‐class transformations are reported, including the preparation of aliphatic SF 4 Cl intermediates, their transformation into aliphatic sulfur pentafluoride analogs, and post‐functionalizations that allow accessing highly complex SF 4 ‐bridged scaffolds.