Modular radical cross-coupling with sulfones enables access to sp3-rich (fluoro)alkylated scaffolds

A sulfur matchmaker for fluorous coupling Fluorination is a burgeoning technique for fine-tuning the properties of pharmaceutical compounds. Unfortunately, the cross-coupling reactions widely used to make carbon-carbon bonds in drug research can be tripped up by fluorine substituents. Merchant et al. report a class of easily prepared, solid sulfone compounds that engage in nickel-catalyzed coupling of their fluoroalkyl groups with aryl zinc reagents. These sulfones considerably simplify the synthetic routes to fluorinated analogs that would previously have required multistep strategies focused strictly on the fluorination protocol. Science, this issue p. 75 Stable sulfone compounds facilitate introduction of fluoroalkyl substituents into targets for medicinal chemistry research. Cross-coupling chemistry is widely applied to carbon-carbon bond formation in the synthesis of medicines, agrochemicals, and other functional materials. Recently, single-electron–induced variants of this reaction class have proven particularly useful in the formation of C(sp2)–C(sp3) linkages, although certain compound classes have remained a challenge. Here, we report the use of sulfones to activate the alkyl coupling partner in nickel-catalyzed radical cross-coupling with aryl zinc reagents. This method’s tolerance of fluoroalkyl substituents proved particularly advantageous for the streamlined preparation of pharmaceutically oriented fluorinated scaffolds that previously required multiple steps, toxic reagents, and nonmodular retrosynthetic blueprints. Five specific sulfone reagents facilitate the rapid assembly of a vast set of compounds, many of which contain challenging fluorination patterns.