Rhodium-Catalyzed Decarboxylative Michael Reaction of Coumarin-3- Carboxylic Acids with N-heterocycles Triggered by C-H Bond Functionalization

Rhodium-catalyzed hydrocarbon bond activation of N-heterocycles and decarboxylative Michael addition with coumarin-3-carboxylic acids has been well achieved. Various N-heterocycles substituted 3,4-dihydrocoumarin could be easily provided with excellent chemo- and regioselectivity in good to excellent yields. A class of functional groups on N-heterocycles and coumarin-3-carboxylic acids is compatible with this process. A stoichiometric amount of Zn(OAc)2 is necessary for the high yield of products.