When SF outplays CF: effects of pentafluorosulfanyl decorated scorpionates on copper.

Polyfluorinated, electron-withdrawing, and sterically demanding supporting ligands are of significant value in chemistry. Here we report the assembly and use of a bis(pyrazolyl)borate, [PhB(3-(SF)Pz)] that combines all such features, and involves underutilized pentafluorosulfanyl substituents. The ethylene and carbonyl chemistry of copper(i) supported by [PhB(3-(SF)Pz)], a comparison to the trifluoromethylated counterparts involving [PhB(3-(CF)Pz)], as well as copper catalyzed cyclopropanation of styrene with ethyl diazoacetate and CFCHN are presented. The results from cyclopropanation show that SF groups dramatically improved the yields and stereoselectivity compared to the CF.