Tandem C-C Bond Cleavage of ­Cyclopropanols and Oxidative Aromatization by Manganese(IV) Oxide in a Direct C-H to C-C Functionalization of Heteroaromatics

We report a direct C–H to C–C bond functionalization of electron‐deficient heteroaromatics enabled by mild C–C bond cleavage of cyclopropanols as a new route to β‐aryl carbonyl‐containing products. Additionally, as an alternative to using a “catalyst” that requires an excess amount of a sacrificial oxidant for regeneration and/or oxidative aromatization, this paper features manganese(IV) oxide as an inexpensive “dual role” reagent – effecting both C–C bond cleavage and ultimate rearomatization. Under the specified conditions, a variety of heterocycles proved competent for regioselective C–C bond formation, alongside a diverse array of cyclopropanols with broad functional‐group tolerance. We highlight applications to complex‐molecule synthesis and direct derivatization of biologically active alkaloids. Furthermore, kinetic isotope effect (KIE) experiments, radical scavengers, and some insight into the application of tri‐ and tetravalent manganese species are invoked to shape an initial mechanistic hypothesis. Manganese(IV) oxide plays a dual role in this C–C bond‐forming reaction involving cyclopropanols and heteroaromatics. A diverse substrate scope and good yields are highlighted, as well as potential applications to natural product synthesis, complex molecule derivatization, and preliminary mechanistic investigations.