Transition-Metal-Free Direct Trifluoromethylthiolation and Trifluoromethylsulfoxidation of Electron-Rich Aromatics with CF3SO2Na in the Presence of PCl3.

A new transition-metal-free route for the direct trifluoromethylthiolation and trifluoromethylsulfoxidation of electron-rich aromatics with CF3SO2Na in the presence of PCl3 was developed. Notably, PCl3 was used as a reducing and chlorination reagent. The transition-metal-free protocol utilized cheap and readily available reagents and exhibited good atom economy; therefore, it will serve as an alternative and practical strategy for the trifluoromethylthiolation and trifluoromethylsulfoxidation of electron-rich aromatics.

Tetrabutylammonium Iodide-Promoted Thiolation of Oxindoles Using Sulfonyl Chlorides as Sulfenylation Reagents.

3-Sulfanyloxindoles were synthesised by triphenylphosphine-mediated transition-metal-free thiolation of oxindoles using sulfonyl chlorides as sulfenylation reagents. The above reaction was promoted by iodide anions, which was ascribed to the in situ conversion of sulfenyl chlorides into the more reactive sulfenyl iodides. Moreover, the thiolation of 3-aryloxindoles was facilitated by bases. The use of a transition-metal-free protocol, readily available reagents, and mild reaction conditions make this protocol more practical for preparing 3-sulfanyloxindoles than traditional methods.

Iodine-catalysed regioselective thiolation of flavonoids using sulfonyl hydrazides as sulfenylation reagents.

Iodine-catalysed regioselective sulfenylation of flavonoid derivatives with sulfonyl hydrazides was developed. Various flavonoid thioethers were obtained in moderate to good yield. The thiolation could be conveniently directed to C-8 for flavone, flavonol, dihydroflavone, and isoflavone derivatives or to C-7 for aurone derivatives by employing the isopropyl ethers of flavonoids bearing free OH groups at the C-5 or C-4 positions.