Studies On Dearomative Spirocyclization Reactions Of Alkyne-tethered Phenol-based Biaryls

The dearomatization reaction of aromatic compounds is the main method for the construction of complicated spirocyclic and polycyclic molecules.Among them,as subunits of aromatic hydrocarbon compounds,the dearomative spirocyclic reaction of phenol and its derivatives has attracted more and more research interests of chemists.The highly functionalized spirocyclohexenone structure molecules by the dearomative spirocyclic reaction of phenol compounds are a class of high-value chemicals,because of these chemicals are significant core fragments of the cyclic natural products with important biological activities,pharmaceutical active molecules as well as functional material molecules.Therefore,research on the dearomatization of phenol and its derivatives is of great significance for promoting the development of medicine,life sciences and other fields.Therefore,based on this,the dissertation mainly includes the following several parts:The first part,we summarizes the development status of aromatic compound dearomatization in detail and presents the main work during the postgraduate period.The second part,we synthesized new alkynes tethered aryl phenol as starting substrates and systematically studied the intermolecular tandem/dearomatization of alkynes tethered aryl phenol with different coupling reagents such as allyl iodides,alkynyl bromides and alkyl iodides under the catalysis of transition metal palladium.A variety of allyl-,alkynyl-and alkenyl-containing spirocyclohexenone molecules were prepared with high selectivity,and the reaction showed good substrates scope.Mechanistic studies showed that these reactions underwent the formation of hydrocarbyl palladium intermediates and the cascade dearomative spirocyclization of alkynes tethered aryl phenol.The third part,we still choose alkynes tethered aryl phenol as starting substrate and respectively carried out the cascade dearomatization reaction of alkynes tethered aryl phenol with electrophilic iodine and diaryl diselenides.A series of spirocyclic cyclohexadienone compounds with carboniodine bonds and carbon-selenium bonds were efficiently prepared,and the iodine-substituted spirocyclohexenone molecules were successfully used as couplers in the coupling reaction of palladium-catalyzed hydrazones.The reaction has the advantages of mild conditions,simple operation,and a wide range of substrates.These works have developed and enriched the synthetic methods for the construction of spirocarbocyclic frameworks molecules and provided a feasible method for the synthesis of active molecules with similar to the skeleton.