Investigation On Nitrile Compounds Participated In Construction Of Carbon-carbon And Carbon-heteroatom Bond Formation

The development of general and efficient methodologies for the synthesis of high-added-value compounds from easily available materials is the central focus of mordern organic chemistry.Nitriles are an important class of organic compounds containing a cyano group（-CN）,which is widely used as intermediate and raw material.It is characterized by high stability,low cost and wide varieties.They not only could be easily transferred into various valuable functional groups,but also applied widely as key intermediates in compounding various natural products,biologically active molecules and designed functional materials.The carbon-nitrogen triple bond cleavage of nitriles required extraordinarily large bond dissociation energy,thus they are quite stable under mild conditions.It is generally known that nitriles such as acetonitrile or benzonitrile have been used as solvents or ligands in organometallic reactions.Therefore,the development of high efficiency and high atom economic approach to useful compounds using common nitriles as substrates remains a challenging area for exploration.In this context,our objectives are to develop catalytic system or metal-free conditions to selectively build new carbon-carbon and carbon-heteroatom bonds to create useful molecules from common nitriles.The details are summarized as follows:（1）We have successfully developed a novel method to synthesize a series of aryl ketone derivatives from arylhydrazines and inexpensive nitriles via a palladium-catalyzed coupling reaction.Taking into account the combination of some desirable features,such as readily accessible starting materials,operational simplicity,molecular oxygen as the sole oxidant,good tolerance to scale-up synthesis,as well as nontoxic gaseous N₂ as the by-products,Controlledexperimentsrevealedthat the mechanism involving the Pd^II/Pd⁰ catalytic cycle and go through a cationic palladium intermediate process.（2）We researched a palladium-catalyzed sequential one-pot cyclization reaction construct a series of 1H-indene and phthalimide derivatives form 2-bromobenzonitriles or2-（2-bromophenyl）acetonitriles,isonitriles,and aminesa.The products were easily isolated by precipitation in moderate to excellent yields for a wide range of substrates,making this a highly attractive method for the synthesis of 1H-indenes and phthalimides.（3）We researched a copper-catalyzed for the synthesis of substituted quinazolines from benzonitriles and 2-ethynylanilines via annulation/cyclization process.Oxygen is not only used as an oxidant,but also plays a very important role in promoting the cleavage of carbon-nitrogen bond and carbon-carbon bond.Controlledexperimentsrevealedthat aromatic nitrile coordinates with KO^tBu to form complexes have profound impacts on reaction paths and selectivity.（4）We researched KO^tBu-mediated annulation reaction of benzonitriles with2-ethynylanilines:synthesisofseriesofquinazoline-substitutedetheneswith aggregation-induced emission（AIE）.The AIE molecules have great value to application and research in the material fields.In contrast with traditional method for the synthesis of such molecules,the present work features advantages including mild conditions,facile operation,rapid reaction rate,high selectivity,easily available starting materials and atom economy,etc.In addition,optical research shows that the introduction of appropriate electron-donating or electron-withdrawing substituent into the quinazoline-substituted ethene skeleton can effectively tune the range of emission colors.The restricted intramolecular rotation effect is the main reason for the products show AIE phenomenon.This protocol will provide a clue about the further development of new types of AIE luminescent materials.