Manganese-Catalyzed C(sp2)-H Addition to Polar Unsaturated Bonds

Transition-metal-catalyzed nucleophilic C-H addition of hydrocarbons to polar unsaturated bonds could intrinsically avoid prefunctionalization of substrates and formation of waste byproducts, thus featuring high step- and atom-economy. As the third most abundant transition metal, manganese-catalyzed C-H addition to polar unsaturated bonds remains challenging, partially due to the difficulty in building a closed catalytic cycle of manganese. In the past few years, we have developed manganese catalysis to enable the sp2-hydrid C-H addition to polar unsaturated bonds (e.g., imines, aldehydes, nitriles), which will be discussed in this personal account.