Study On Transition Metal-Catalyzed Synthesis Of Chloroalkynes And Derivations Of Cyanoalkynes To Form Indoles And Conjugated Enyne

Haloalkynes have always been the important parts in organic synthesis. They have unique C(sp)-X bond which has controllable electrophilic and nucleophilic properties. Thus, when participating in chemical reaction, haloalkynes are flexible. Chloroalkynes is a kind of haloalkynes, howerver, research about it is rare, and one of the reasons is that there is no good method for its synthesis. As alkynes pseudohalogn substitution derivative, cyanoalkynes is concerned by people for its special structure that double unsaturations exist in C(sp)- C(sp) conjugated manner, so they have great potential in the construction of small important organic molecules. In this thesis, this paper try to find a good method for the synthesis of chloroalkynes by transition metal catalyzed organic reaction; using cyanoalkynes synthesize indoles, nitrile conjugated enyne functional small molecules. The main contents of this thesis are as follows:1. Chloroalkynes were prepared in good yields with terminal alkyne as raw material directly, and N-chlorosuccinimide as common chlorine source, relatively stable and easy to get silver carbonate as catalysis, and potassium carbonate as a base, under an inert atmosphere. This method is of good in substrate applicability, and many functional groups can be tolerated. Compared with traditional methods, this method has some features such as cheap and readily available raw materials, mild reaction conditions, simple operation, low toxicity, and relatively environmental friendly.2. Indoles were synthesized using cyanoalkynes and substituted anilines as raw material by palladium acetate catalysis in one pot. The reaction uses oxygen as the oxidant, avoiding possible contamination caused by other high-priced metal oxidants and oxidizing organic. In addition, one-pot reaction can avoid the isolation of the intermediate, which simplifies the operation. The reaction mechanism was verified by experiments. Palladium insert alkenyl hydroxide position of the enamine, cyclization occurs with benzene, and the palladium removed to form an indole ring, and the reducing to zero-valent palladium were oxidized by oxygen giving divalent palladium.3. In the presence of an excess of triethylamine, 5% of 1,4-bis(diphenylphosphino) butane palladium dichloride catalyst can effectively promote cyanoacetylene and terminal alkyne addition of conjugated enynes generated nitrile. The analysis of NMR spectrum could prove that the reaction is good in steric selectivity, which substantially generate a single configuration nitrile conjugated enyne. Moreover, it is characterized as simple reaction condition and good functional group compatibility, so it is likely to be used to synthesize multivariate conjugated enyne nitrile.