Onward to simpler C–H functionalizations | Chemical & Engineering News
Volume 94 Issue 44 | p. 13 | Concentrates
Issue Date: November 7, 2016

Onward to simpler C–H functionalizations

Chemists develop a new class of copper catalyst for aromatic imidations and a simple selectivity rule to predict product outcome
Department: Science & Technology
News Channels: JACS In C&EN, Organic SCENE
Keywords: catalysis, C–H activation, C–H functionalization, C–N bond formation, imidation, amination

Selective C–H activation and functionalization has emerged as an integral strategy for organic synthesis. Chemists have already developed an abundant set of methods, and many researchers are now turning to finding ways of simplifying those strategies. In one of the latest examples, a team led by Kenichiro Itami of Nagoya University and Djamaladdin G. Musaev of Emory University has used a computational-experimental approach to create a predictive regioselective reaction for C–H imidation of aromatic compounds (Chem. Sci. 2016, DOI: 10.1039/c6sc04145k). One hurdle for C–H functionalization has been that it’s a two-electron oxidation process, but inexpensive first-row transition metals used as catalysts typically are capable of one-electron redox activity. The way around this problem is to use two concurrent one-electron oxidations, which typically requires two catalysts. Itami, Musaev, and their team have found that treating copper bromide and a bipyridine ligand with the commercially available oxidizing reagent N-fluorobenzenesulfonimide (NFSI) leads to a new class of dinuclear copper catalysts in which the two Cu(II) centers work collectively to guide NFSI-promoted aromatic C–H imidation. As a bonus to the process, the researchers developed a way to calculate the charge on carbon atoms in aromatic molecules to predict which C–H bond is favored for imidation (shown above).

 
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