Studies On Several Transition Metal-catalyzed Carbon-carbon And Carbon-heteroatom Bond Forming Reaction

Transition metal-catalyzed C-C, C-heteroatom bond forming reactions, including conventional cross coupling reactions, C-H functionalization and decarboxylic coupling etc, are central synthetic tactic in current organic synthesis, The transition metal catalysis-based synthesis of aromatic and heteroaromatic compound are highly useful in the areas of medicinal chemistry, materials and biologically active molecules. This thesis present our researches on several transition metal-catalyzed C-C and C-heteroatom reactions for the synthesis of different small molecules. The whole thesis consists of four sections.(1) Copper-catalyzed C-S coupling reactions of electron deficient heteroaryl thiophenols and aryl halides. Under the condition of copper catalysis, the reactions of aryl halides and heteroaryl thiophenols were investigated by condition optimization and scope examination, by which a new method for the synthesis of heteroaryl sulfides via the coupling reactions between heteroaryl thiophenols and aryl halides was established. This method provided a new route to the synthesis of diverse heteroaryl sulfides.(2) Copper-catalyzed tandem reactions for indoles synthesis. The tandem reactions started from simple reactants acyl chlorides, Witigg reagents and o-iodoanilines. Under the condition of copper catalysis, the acryl chorides reacted with Witigg reagents to provide allenes in situ, o-iodoanilines then reacted with allenes to provide structurally diverse indoles via tandem transformations of Michael addition, C-C coupling and tautomerization. The work in this section established a new approach toward the synthesis of indoles.(3) Palladium-catalyzed, C-H arylation-based multicomponent, one-pot tandem reactions for o-arylphenylacetamide synthesis. The reactions employed phenylacetyl chlorides, 8-aminoquinolines and iodobenzenes as starting materials. The aminoquinoline directing group was installed in situ via the reactions of phenylacetyl chlorides and 8-aminoquinoline, which subsequently assembled with iodobenzenes via ?-C-H activation, and provided arylated amides. Meanwhile, by modifying reaction conditions, we successfully realized the selective mono- and diarylation of two identical C-H bonds, and built up a new type of efficient directing group assisted C-H activation reactions.(4) Copper-catalyzed degradative amidation reactions of phenylacetic acids for the synthesis of N-pyridinyl benzamides. Starting from phenylacetic acids and 2-aminopyridines, the copper-catalyzed tandem oxidative degradation and oxidative carbonylation took place and enabled the synthesis of a series of N-pyridinyl carboxamides containding phenyl, heteroaryl and napthyl etc. The work disclosed the new model of transformation and phenylacetic acids and its application potential in the synthesis of amides.