Palladium Catalyzed Carbon-carbon Coupling Reactions Enabled By Thioether Ligands

3H-naphtho[2,1-b]pyran-3-one is a kind of compound with coumarin as its basic skeleton,and 2-phenylnaphtho[2,1-b]furan is a kind of compound with benzofuran as its basic skeleton,so they all have certain potential social and economic value.In this dissertation,a palladium catalyzed C-C coupling reaction with hydroxyl group as the guiding group was developed in the presence of 3-(4-methoxyphenyl)thiopropane-1-sulfonate as a ligand.A series of 3H-naphtho[2,1-b]pyran-3-one and 2-phenylnaphtho[2,1-b]furan were synthesized.The reaction has the advantages of low cost and easy synthesis of raw materials(naphthol substrate,acrylate and styrene),mild reaction conditions,no need of inert gas protection,simple operation,and less pollution with acetic acid as solvent.A novel synthesis method of 3H-naphtho[2,1-b]pyran-3-one was developed using naphthol and acrylate as substrates.In this method,palladium acetate was used as catalyst,sodium 3-(4-methoxyphenyl)thiopropane-1-sulfonate was used as ligand,benzoquinone as oxidant and acetic acid as solvent.After a series of conditions screening,the optimal reaction conditions were obtained.At the same time,a series of 6-phenyl-2-naphthol substrates were designed and synthesized according to Suzuki Miyaura coupling reaction under optimal conditions,a series of naphthopyran-3-ones were synthesized from 2-naphthol and 6-phenyl-2-naphthol substrates with different substituents.The yields of these compounds ranged from30% to 90%.2-phenylnaphtho[2,1-b]furan were synthesized by palladium catalyzed carbon carbon coupling reaction between naphthol substrates and styrene compounds.After obtaining the same optimal conditions,according to the conditions,a variety of styrene,2-naphthol and 6-phenyl-2-naphthol substrates with different groups were explored.Finally,16 kinds of 2-phenylnaphtho[2,1-b]furan were successfully synthesized,with the yields ranging from 15% to 32%.A more feasible reaction mechanism was proposed,and the intermediate was designed to verify the reaction mechanism.The mechanism of the reaction is as follows: the ligand and catalyst coordinate to form an active species with empty coordination sites.The active species coordinate with naphthol substrates to form a complex.The carbon carbon double bond in acrylate or styrene reacts with the carbon palladium single bond in the complex to complete the construction of new carbon carbon bond.At the same time,a new active complex is formed and ?-hydrolysis occurs.In addition,the intermediates and palladium hydrogen compounds are formed,and the intermediate further reacts to produce the target product,and the palladium hydrogen compound reacts with the oxidant to regenerate the catalytic active species,thus completing the cycle of catalytic reaction.