Abstract
The direct transformation of C-H bonds has attracted much interest in recent years, because it avoids prior functional group manipulations for the synthesis of a pre-activated precursor and thus greatly streamlines synthetic sequences. Among such reactions, functionalization of unreactive C(sp3)-H bonds is particularly advantageous for construction of highly complex natural products, which generally contain a high ratio of sp3-hybridized carbon centers. However, this extremely useful reaction remains challenging mainly due to the lack of general strategies for activating inert C(sp3)-H bonds. We developed four reagent systems for direct C-H oxidation, and established three carbon-chain elongations via straightforward installation of carbon unit to C-H bonds. Highly reactive chemical species acting like oxygen radical are utilized as a key C-H activator.
