Reactions of Fluoroölefins with Sulfur Trioxide

Chemoselective Reactions of Functionalized Sulfonyl Halides

Chemoselective transformations of functionalized sulfonyl fluorides and chlorides are surveyed comprehensively. It is shown that sulfonyl fluorides provide an excellent selectivity control in their reactions. Thus, numerous conditions are tolerated by the SO2 F group - from amide and ester formation to directed ortho-lithiation and transition-metal-catalyzed cross-couplings. Meanwhile, sulfur (VI) fluoride exchange (SuFEx) is also compatible with numerous functional groups, thus confirming its title of "another click reaction". On the contrary, with a few exceptions, most transformations of functionalized sulfonyl chlorides typically occur at the SO2 Cl moiety.

Methyl fluorosulfonyldifluoroacetate (MFSDA): An Underutilised Reagent for Trifluoromethylation

The introduction of fluorine groups to pharmaceutical compounds can have a dramatic effect on the lipophilicity and metabolic stability of the molecule in vivo. Around 20 % of drugs contain at least one fluorine atom. The trifluoromethyl group is known to have beneficial effects and can dramatically affect the biological activity when substituted for a methyl group, for example. In any case, the direct and late-stage introduction of a trifluoromethyl group is a powerful transformation in the tool box of the medicinal chemist. The use of methyl fluorosulfonyldifluoroacetate (MFSDA) as a relatively inexpensive reagent for trifluoromethylation was first reported in 1989; however, in our opinion it has been somewhat underutilised. Herein, a comprehensive review of trifluoromethylation using MFSDA is reported, which we hope will further expose readers to this useful reagent.

Sulfonyl chloride activation of hydroxylic materials

We have discovered that chromophoric sulfonyl chlorides and affinity ligand-containing sulfonyl chlorides prepared based upon fluorinated carbon skeletons are excellent activating agents for agarose. The primary basis for development of such reagents has been pentafluorobenzenesulfonyl chloride and tresyl chloride, both of which are excellent activating agents. Activation using the sulfonyl chlorides whose synthesis is described here has yielded matrices that are very reactive to nucleophilic displacement by amines and thiols and, thus, should be excellent agents for the immobilization of affinity ligands, enzymes, cells, etc. The resulting material is based on covalent coupling and, thus, is more stable than affinity ligands or enzymes immobilized by other methods.