Synthesis Of C-C And C-O Bonds From Arylcopper(Ⅲ) Intermediates

Because of the great potential in synthesis, direct C-H bond activation andfunctionalization have been regarded as a Holy Grail, attracting ever growing interest.In comparison to noble metals, copper salts are more cost-effective, less toxic and morefriendly benign, and copper salts catalyzed or mediated C-H activation andfunctionalization appear more interesting and advantageous. Although organocopper（III）species have been hypothesized as intermediates in many copper-involved reactions,solid evidence is still very rare. The in-depth study is highly demanding and ofsignificant in the understanding of the mechanism of organocopper（III） species and inthe design of copper-catalyzed reactions. This Ph.D. thesis is aimed to study thereactions of azacalix[1]arene[3]pyridine-derived arylcopper（III） complex with oxygennucleophiles such as alcohols and phenols and with alkynyl and alkyl lithium reagentsin order to establish and develop new methods for the construction of C-O and C-Cbonds.In the presence of1,8-Diazabicyclo[5.4.0]undec-7-ene （DBU） as a base, thearyl-copper（III） complexes reacted with primary and secondary alcohols and varioussubstituted phenols to form C_aryl-O bond in good yields. The chiral alcohols such as（S）-2-methylbutanol and （S）-2-phenylethanol also reacted with aryl-copper（III）complexes to produce chiral azacalix[1]arene[3]pyridine. The C_aryl-O bond formationreaction was also achieved from Cu（ClO4）2-mediated direct C-H bond activation andsubsequent alkoxylation of azacalix[1]arene[3]pyridine in a one pot reacion.The reaction between arylcopper（III） complexes and alkynyl lithium reagentsproceeded effectively at room temperature to afford C_aryl-Cspbond. The method allowedthe synthesis of a variety of alkynylated azacalix[1]arene[3]pyridine products.Copper salt mediated direct alkynylation of azacalix[1]arene[3]pyridine with analkynyl lithium was realized in a convenient one-pot reaction fashion. Startingfrom iodobenzene-containing azacalix[1]arene[3]pyridine, Cu（I）-mediatedCastro-Stephens reaction with a terminal alkyne proceed via a structurally welldefined arylcopper（III） intermediate to form a C_aryl-Cspbond. The outcomes suggestan alternative mechanism of Castro-Stephens reaction that comprises the oxidativeaddition of Cu（I） into C-I bond to form an arylcopper（III） intermediate.The C_aryl-C_sp3bond has also been constructed from the reaction of arylcopper（III）complexs with alkyl lithium reagents in moderate yields. One pot reaction withoutisolation and purification of arylcopper（III） intermediate has been successfully carriedout from Cu（ClO4）2-mediated direct C-H bond activation and cross coupling with analkyllithium. A mumber of alkylated azacalix[1]arene[3]pyridine have been synthesized.In conclusion, we have shown the reactivity of structurally well definedarylcopper（III） complexes toward both oxygen and carbon nucleophiles. The newmethod has been developed for the construction of C_aryl-O, C_aryl-Cspand C_aryl-C_sp3bond. The synthesis of C-O and C-C bonds has also been demonstrated by a convenientone-pot reaction between azacalix[1]arene[3]pyridines and oxygen and carbonnucleophiles, respectively without isolation and purification of arylcopper（III）intermediate. The C-H bond activation provides a unique approach to a variety offunctionalized azacalixaromatics, which are valuable macrocyclic host molecules insupromolecular chemisty.