Alkyne Or Olefins-mediated Functionalizations

Alkynes and olefins can exhibit unique chemical properties in organic synthesis dueto their triple and double carbon-carbon bond. Thus, functionalization of alkynes orolefins has become an important research in organic chemistry. Over the past fewdecades, alkynes have gained much attention of organic synthesis chemists, since theywere employed as the alkynyl reagents of Sonogashira coupling or the source of alkenylgroups in the addition reactions. The direct functionalization of olefins provides a simple,inexpensive and effective way for synthesis of many natural products, drug moleculesand fine chemical products. Based on the previous works in this area, we wish to discloseour recent development on their further applications in synthetic organic chemistry.This dissertation is made up of four chapters:Chapter one is about Pd/Cu co-catalyzed couplings of heteroaryl halides with variousalkynes. The reactions of heteroaryl bromides and chlorides with terminal alkynes can beperformed with the excellent yields using Pd/Cu co-catalyzed system at roomtemperature. In addition, we also studied the fluorescence properties of the product of thedialkynylation of benzofuran, which can be proved to be used as a potential fluorescentmaterial.Chapter two is about Pd-catalyzed coupling between arylboronic acids and alkynesor alkynyl carboxylic acids. The optimized oxidative alkynylation coupling in the catalystsystem was palladium complex/silver oxide/potassium acetate. Thiosemicarbazone Pd(II)complexes have shown high efficiency and high stability for coupling reactions whichmakes them to complete the catalytic cycle effectively.Chapter three is about transition-metal-free synthesis of N-(1-alkenyl)imidazoles via potassium phosphate-promoted addition reaction of alkynes to imidazoles. Thesereactions were operationally simple, and afforded good yields with high chemical andstereo selectivities.Chapter four is about copper-catalyzed oxyalkylation of vinylarenes under aerobicconditions via cleavage of sp3C–H bonds to nitrogen. We described here aCuF22H2O/TBHP system for the radical addition reaction of aromatic olefins to sp3C-Hradical to nitrogen with moderate yields. It presents a simple, direct, low-cost andeffective protocol for synthesis of1,5-dicarbonyl amide.