A New Portal to SuFEx Click Chemistry: A Stable Fluorosulfuryl Imidazolium Salt Emerging as an “F−SO2+” Donor of Unprecedented Reactivity, Selectivity, and Scope

• Published in: Angewandte Chemie International Edition 2018-03, Vol.57 (10), p.2605-2610
• Main Authors: Guo, Taijie, Meng, Genyi, Zhan, Xiongjie, Yang, Qian, Ma, Tiancheng, Xu, Long, Sharpless, K. Barry, Dong, Jiajia
• Format: Article
• Language: English
• Subjects: Amines; azolium salts; Chemical synthesis; click chemistry; Fluorides; fluorosulfurylation; Imides; Phenols; Salts; Selectivity; Substrates; SuFEx chemistry; sulfamoyl fluoride; Sulfur dioxide; Sulfuryl fluoride; Triethylamine
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201712429

Sulfuryl fluoride, SO2F2, has been found to derivatize phenols in all kinds of environments, even those in highly functional molecules. We now report that a solid fluorosulfuryl imidazolium triflate salt delivers the same “F−SO2+” fragment to Nu−H acceptor groups in the substrates. However, this triflate salt is a far more reactive fluorosulfurylating agent than SO2F2 and displays selectivity preferences of its own. Moreover, the new azolium triflate reagent reacts once with primary amines and anilines before the reaction stops. On the other hand, with triethylamine and two equivalents of the “F−SO2+” donor present, it proceeds on to the bis(fluorosulfuryl)imides in good yield—two important conversions that we have never seen with sulfuryl fluoride as the electrophile. A fluorosulfuryl imidazolium salt delivers the “F−SO2+” fragment to Nu−H acceptor groups (phenols and amines) in various substrates. This new azolium triflate reagent reacts once with primary amines and anilines before the reaction stops. However, with triethylamine and two equivalents of the “F−SO2+” donor present, it proceeds on to the bis(fluorosulfuryl) imide in good yield.