Tweezer‐Based C−H Oxidation Catalysts Overriding the Intrinsic Reactivity of Aliphatic Ammonium Substrates

New supramolecular tweezer catalysts capable of oxidizing strongly deactivated C3/C4 positions of aliphatic ammonium salts were synthesized. The best performing catalyst Fe(pdp)Twe was explored in the oxidation of new substrates.

Abstract

The site-selective C−H oxygenation of alkyl chains as well as deactivated positions remains a great challenge for chemists. Here, we report the synthesis and application of four new supramolecular tweezer-based oxidation catalysts. They consist of the well-explored M(pdp/mcp) oxidation moiety and a molecular tweezer capable of binding ammonium salts. All catalysts display preferential oxidation of the strongly deactivated C3/C4 positions, however to different degrees. Furthermore, the best performing catalyst Fe(pdp)Twe was explored with an expanded substrate scope. It was demonstrated that the deactivated positions C3/C4 are also preferentially oxidized in these cases.

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