Study On The Synthesis Of Amide Via Tandem Catalyzed C≡C Bond Cleavage

Tandem catalytic reaction with outstanding characteristics can achieve multistep transformation by one-pot, has attracted more and more attention of chemists.Carbon-carbon bond is the basic unit of chemical bond in organic compounds, to achieve the cleavage of carbon-carbon bond and its subsequent functionalization is an important task in organic chemistry, and helps to the utilization of organic compounds.However, these researches are full of challenge due to the relative inertness of carbon-carbon bond. The research about C≡C bond cleavage and transformation are less, mainly concentrate on the hydrogenation, oxidation, hydroamination etc.. At the same time, amides are an important class of organic compounds, which are widely applied in the fields of pharmaceutical industry, material science, agricultural chemical, biochemistry etc., Direct conversion from alkynes to amide, not only has important scientific significance, but also has certain significance of synthesis. In this paper, the palladium/copper tandem catalyzed C≡C bond cleavage and C-N bond formation as the foundation, under mild reaction conditions, for the first time,achieving the transformation of diphenyl acetylene, and reacting with aniline by one-pot, finally we get N-phenylbenzamide.The main contents of this paper are as follows:Firstly, palladium copper tandem catalyzed diphenyl acetylene cutting C≡C bond synthesis of N-phenylbenzamide: exploration and optimization of reaction.We selected aniline and diphenylacetylene as substrate, after a series of optimization of conditions(catalysts, oxidant, ligands, solvents, etc.), we got the optimum reaction conditions: aniline(0.2 mmol), diphenylacetylene(0.4 mmol), PdCl2(10 mol%),CuCl2·2H2O(20 mol%), DPPE(10 mol%), 1,10-phen·H2O(40 mol%), AgOTf(20mol%), H2O(5 eq.), dioxane(0.25 mL). The mixture was stirred and heated at 100 °C.Secondly, substrate range and adaptability of the target reaction. The reactions of various substituted anilines and diphenylacetylenes were carried out under the optimized reaction conditions to test the reaction applicability. The experiments proved the fact that this method had wide reaction substances and good compatibility with various functional groups.Finally, we provided the synthetic methods and experimental steps of the raw materials and substituted N-phenylbenzamide. The structure of amide products werecharacterized by 1H NMR and 13 C NMR, We also provided Spectrogram and data.In a word, this paper base on the palladium/copper tandem catalysis, in mild reaction conditions, achieving the C≡C bond cleavage and its subsequent functionalization to get N-phenylbenzamide and provide a new way for the transformation of the C≡C bond. We also make an important supplement for synthesis of amides, which uses alkyne as substrates, having significance of synthesis.