Toward more versatile fluorinations

Abstract

University of Michigan chemists have developed a Lewis acid-base pair strategy to prepare and stabilize a versatile new reagent capable of adding trifluoromethyl groups to molecules. The method promises to expand on current synthetic strategies for making fluorinated pharmaceuticals and agrochemicals while lowering costs and reducing chemical waste. Jacob B. Geri and Nathaniel K. Szymczak conducted a computational study and developed an acid-base affinity scale to help identify hexamethylborazine as the optimal Lewis acid—an electron-pair acceptor—to go with trifluoromethyl anion as the Lewis base—an electron-pair donor. They carried out the study with the aim of deriving CF3– from fluoroform (CHF3), an industrial waste product and potent greenhouse gas, while also allowing for simple CF3– transfer from the acid-base pair to a range of inorganic and organic electrophilic reagents (J. Am. Chem. Soc. 2017, DOI: 10.1021/jacs.7b05408). Chemists have previously developed acid-base trifluoromethylating reagents, including the widely used trifluoromethyltrimethylsilane (TMSCF3). These reagents