Hypervalent iodine-mediated selective oxidative functionalization of (thio)chromones with alkanes

Abstract

C-C bond formation is the most fundamental way for the chain propagation in organic molecules. This achievement through tandem oxidation of two different C-H bonds represents the state of the art in organic synthesis. Selective functionalization of the ubiquitous aliphatic C-H bonds offers an attractive option for this oxidative cross-coupling methodology. To develop such a methodology under mild and "metal-free" conditions remains challenging. Herein, we report hypervalent iodine-mediated selective oxidative functionalization of aliphatic C-H bonds of alkanes with chromones and (thio)chromones. A wide range of alkanes, both cyclic and acyclic, has been found to react selectively and predictably in good yields. The developed methodology is also the first report of a direct oxidative functionalization of the C-2 position of (thio)chromones with alkanes to access bioactive compounds. Hypervalent iodine: An efficient IIII-mediated selective oxidative functionalization of alkanes with chromones and (thio)chromones has been developed. The developed methodology provides a direct access to the 2-alkyl chromones under metal-free and ambient conditions. Both cyclic and acyclic alkanes can be selectively functionalized (see scheme). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.