Synthesis Of Ortho-Alkenyl Phenol Derivatives

Ortho-alkenylphenol is a common skeleton of biologically active molecules,such as Ratanhine,Oxyresveratrol.At the same time,ortho-alkenylphenol is also an important synthetic intermediator,which can be converted into complex drug molecular skeletons easily,such as coumarin,benzoxanthine,benzopyran and so on.The reported synthesis methods of ortho-alkenylphenol were usually of low atom economy,poor selectivity,or using of strong acids and other harsh conditions that resulted in poor functional group compatibility for those reactions.In order to solve the above problems,we planned to develop new methods to construct the ortho-alkenylphenol skeleton efficiently in one step from stable,cheap,and easily available raw materials,which not only conformed to the principles of green chemistry,but also met the strategic requirements of sustainable development.Therefore,this dissertation mainly focused on the synthesis of ortho-alkenylphenol in the following two parts:（1）Nickel-catalyzed ring-opening conversion of benzofuran with silane into ortho-alkenylphenol derivatives:the reaction was conducted under nitrogen atmosphere,benzofuran and silane was used as starting material,Ni（cod）₂ as catalyst with PCy₃ or NHC as ligand,the ortho-alkenylphenol derivative containing silicon protecting group was obtained in high yield.This method had the characteristics of high yield and broad substrate scope.In addition,benzofuran compounds were used as raw materials,which were cheap and easy-to-obtain by numerous synthesis methods.（2）Tris（pentafluorophenyl）borane catalyzed the addition of phenol derivatives to alkynes:considering the problem that halogen atoms were incompatible in the above nickel catalyzed ring-opening of benzofuran,in this part,we developed a B（C₆F₅）₃ catalyzed the C-C bonding of phenol derivatives and phenylacetylene derivatives using chlorobenzene as the solvent,those transformations used commercially available phenol derivatives and phenylacetylene derivatives as raw materials.The reaction operation was simple,that was,a series of ortho-alkenylphenol could be obtained with good yield and selectivity by adding the corresponding catalyst and solvent at room temperature.