Catalytic Decarboxylation Of Aroylformic Acid With Tetrahydroquinoline Derivatives By Palladium

Aryl ketones are important pharmaceutical motifs and chemical products in pesticides, functional materials and dyes. Aromatic ketones containing tetrahydroquinoline are used as alkaloid, whose ubiquitous distributions are in medicinal agents. They are usually synthesized by Friedel-Crafts acylation and the oxidation dehydrogenation of aryl alcohols. These catalytic transformations need harsh reaction conditions and produce waste. The palladium-catalyzed C-H activation decarboxylation coupling reaction by directing group are widely applied to synthesize aryl ketones compounds due to the mild conditions, preclusion of pre-activation for substances and atom economy. A new palladium-catalyzed C-H activation decarboxylation coupling reaction to give aromatic ketones have been developed in this thesis.Firstly, N-Acetyl-1, 2, 3, 4-tetrahydroquinolines as the new substrates have been designed and the acyl is the directing group. The synthesis route of the substrate has been optimized and 7 different kinds of substrates have been synthesized. Meanwhile, the 12 kinds of α-oxoarylacetic acids as acyl reagent have been obtained by the oxidation of acetylbenzene with different groups.Subsequently, the novel palladium-catalyzed C-H activation decarboxylation coupling reaction has been studied. Optimized reaction conditions have been obtained by screening of catalyst, reaction solvents, oxidants, the quantity of oxidant and reaction temperature. Sixteen 8-aroyl-tetrahydroquinolines are synthesized on the optimal condition. The decarboxylation mechanism has also been hypothesized. All the compounds are characterized by 1H NMR, 13 C NMR and HRMS.The reaction system of preparing aryl ketones only needs mild reaction condition, but has high yield. It is friendly to the environment and has good functional group tolerance.