Carboxylic Oxonium Ylide Trapping Based Three-component Reaction And Synthesis Of Two Kinds Of Oxindole Derivatives

Diazo chemistry has attracted more and more attention due to its diversity in reaction types as well as its high efficiency and high atom economy in organic synthesis. Against this background, in recent years, our group have developed an array of multi-component reactions based on the trapping of active intermediates including ylides and zwitterions. However, the ylides that can be trapped are restricted to ammonium ylides, alcoholic or aquatic oxonium ylides. In this thesis, we initiated our stuty from the exploring of new reactions based on trapping carboxylic oxonium ylides. We not only successfully interceped this kind of active intermediate, but also developed new methods for the synthesis of two kinds of different oxindoles after intensive study of the side reactions.We first studied the three component reaction of carboxylic acids, a-diazoacetophenones and imines. This is the first example in which carboxylic oxonium ylides are intercepted by electrophiles that act as the third component. Through this reaction, an array of relatively complexed a-hydroxy-β-aminoketone derivatives can be synthesized from simple materials. We proposed that the formation of the hydrogen bonding between carboxylic oxonium ylides and imines is crucial for the reaction to occur. This hypothesis was proved to be reasonable by some control experiments.In chapter3, we initiated our study by exploring new reactions based on trapping carboxylic oxonium ylides with α,β-unsaturated imines. The first example of [1+4] cycloaddition of diazo compounds and aza-dienes was found as the unexpected reaction during the analysis of byproduct. The substrate scope of the reaction was examined and an array of potentially bio-active spiro[pyrrolidin-3,2’-oxindoles] were synthesized. The reaction mechanism was verified through conducting control experiments. We also gave explanation for why the reaction shows excellent diastereoselectivity. In, chapter4, we initiated our study by exploring new reactions based on trapping carboxylic oxonium ylides with intramolecular alkynes. Though extensive study of the way how the unexpected product forms, the Friedel-Crafts reaction of diazocompound and arene was found. Under metal-free and mild conditions, an array of3-aryl oxindoles were efficiently synthesized through the highly regioselective reaction of3-diazooxindoles and electron-rich arenes.