Palladium-catalyzed Coupling Of Sp~2C-H Bond Of Electron-deficient Arene And β-acyloxylation Of Alkyl Sp~3C-H Bond Of Simple Amide

C-H activation/functionalization has been developed enormously in recent years and has been emerged as a potentially ideal tool for organic synthesis. Current objects of C-H activation are mainly focused on aryl sp2C-H bonds and alkyl sp3C-H bonds.In the field of sp2C-H activation, synthesis of biaryls via dual C-H activation using arenes as raw materials is one of the challenges. Current reports are mainly concentrated on heteroarenes, directing groups containing arenes, or polyfluoroarenes. Simple arenes are less reported. Moreover, catalytic coupling of electron-deficient simple arenes under mild conditions has not been reported yet. In this dissertation, catalytic homocoupling of electron-deficient simple arenes including nitrobenzene, trifluoromethylbenzene, ethyl benzoate and their derivatives has been fulfilled using Pd(OAc)2/CF.3.CO.2.H/K.2.S.2.O.8. or O2(1atm) oxidative catalytic system (9examples,35-68%yields). Strongly electron-deficient simple arenes such as1,3-dinitrobenzene could also be coupled in this reaction. Besides, highly selective cross-coupling of ethyl benzoate with nitrobenzene or trifluoromethylbenzene is available using esters as directing groups (2examples,55%or56%yields). Furthermore, cross-coupling products of simple electron-deficient arenes without directing groups could also be obtained in moderate selectivity.In the field of sp3C-H activation, both reactivity and selectivity remains problematic. For alkyl sp3C-H bond is more inert than aryl sp2C-H bond, specially synthesized directing groups are normally required to be installed to the substrates in sp3C-H functionalization. Using simple functional groups, which exist naturally in both reactants and products, as directing groups in direct oxygenation of sp3C-H bonds has not been reported. In this dissertation, direct acyloxylation of sp3C-H bonds has been fulfilled utilizing simple amides as effective directing groups in Pd(OAc).2./CF.3.CO.2.H/K2.S.2.O.8oxidative catalytic system. Sole β-C-H acyloxylated products from various N-substituted by linear alkyl, cyclo alkyl, or electron-deficient benzyl2,2-dimethylpropanamide or2,2-dimethylbutanamide could be obtained in moderate to high yields (19examples,63-96%yields). Besides, β-sp3C-H acyloxylation of2-methyrpropanamide or2-ethylbutanamide is also available using N-methoxycarbonylethylene amide as a directing group. All these β-acyloxylated amides could be converted to the corresponding β-hydroxy amides quantitatively under mild conditions.