A Cascade Esterification-Rearrangement Reaction Catalyzed By N-Heterocyclic Carbenes

This thesis is composed of three parts:(1) N-Heterocyclic carbenes, as a kind of versatile organocatalysts, reverse the polarity of aldehydes, resulting umpolung aldehyde, or acyl anion equivalents. The umpolung aldehydes are induced to undergo various nucleophilic reactions. The history of the development of N-heterocyclic carbenes was reviewed. Benzoin condensation, Stetter reaction, a3 to d3 umpolung and Ring expansion, as four kinds of classical reactions catalyzed by N-heterocyclic carbenes were presented. These reactions provide a concise and effective method for construction of carbon-carbon bonds and various functionalized compounds.(2) We have shown that a-bromine-α,β-Unsaturated aldehyde react with various 1,3-dicarbonyl compounds under NHC catalysis to provide dihydropyranones. Only a low loading of a cheap carbene catalyst was required. The reactions were conducted under mild conditions and were easy to run.(3) Five heterocyclic compounds which based on a QSAR model in virtual screening inhibitors targeting STAT3 SH2 domain were synthesized. Anti-tumor activity of the test in progress.