Exploration Of Methodology Based On Aryne And Synthetic Studies Towards Trigonoliimine A

This thesis is mainly focused on aryne-based methodology development and synthetic studies towards trigonoliimine A and consists of three parts.In Part Ⅰ, the preparation methods and the reactions of arynes are reviewed.Part Ⅱ mainly deals with the reaction of arynes and nucleophiles under metal-free conditions. Aryl hydrazines are among the most important intermediates for natural product synthesis, but arylative N-C bond formation still remains one of the most challenging areas in modern organic synthesis. We developed a new method to synthesize aryl hydrazine derivatives by the reaction of an aryne with a1,3-dipole generated in situ from triphenylphosphine and a dialkyl azodicarboxylate. In addition, aryl hydrazine derivatives can be converted to indole and pyrazole derivatives in a one-pot fashion. In addition, some other new reactions based on the high reactivity of arynes towards nucleophiles were investigated and relevant mechanistic studies were performed.In Part Ⅲ, the synthetic studies towards trigonoliimine A was described. Trigonoliimine A, a natural product with an unprecedented polycyclic skeleton, was isolated from the leaves of Trigonostemon. lii Y. T. Chang collected in Yunnan Province of China. Owing to its intriguing chemical structure and interesting biological profile, trigonoliimine A has emerged as an attractive target molecule for the synthetic community. The synthestic studies on trigonoliimine A, featuring a Pictet-Spengler cyclization and a Bischler-Napieralski reaction as the key trasformations, has been conducted in our laboratory.