A Unified Flow Strategy for the Preparation and Use of Trifluoromethyl-heteroatom Anions

The trifluoromethyl group (CF3) is a key moiety in pharmaceutical and agrochemical development, greatly enhancing the efficacy and properties of resulting compounds. However, attaching the CF3 group to heteroatoms such as sulfur, oxygen, and nitrogen poses significant challenges due to the lack of general synthetic methods and reliance on bespoke reagents. In this study, we present a unified approach to address this issue by employing a modular flow platform that streamlines the synthesis of heteroatom-CF3 motifs. Our method utilizes readily available organic precursors in combination with cesium fluoride as the primary fluorine source, facilitating the rapid generation of NCF3(R), SCF3, and OCF3 anions on demand. Despite their reactivity and atom economy, the instability of these anions has previously hindered their widespread application. However, our platform overcomes this limitation, enabling the subsequent coupling of these nucleophiles with a diverse range of electrophiles. This capability allows for the late-stage modification of various drug intermediates, offering a versatile and efficient synthetic route. A notable advantage of our approach is its sustainability. Unlike traditional methods reliant on polyfluoroalkyl substances (PFAS) as reagents, our strategy bypasses their use, resulting in a more environmentally friendly synthesis of trifluoromethyl(heteroatom)-containing molecules. Furthermore, our method expands the chemical space available for the heteroatom-CF3 group, with the potential for scalability in manufacturing processes facilitated by flow technology.