Synthesis And Wittig Olefination Of (2-methyl-3-oxoisoindolin-1-yl)triphenyl Phosphonium Tetrafluoroborate

Wittig olefination reaction is one of the classical reactions to build carbon-carbon double bond in organic synthesis.Isoindolinone is a kind of important compound with biological activity and widely exists in natural base compound.Therefore,it is of great importance to seek effective methods for synthesis of these compounds.We adopted the cheap and accessible phthalimide as the staring material,through reaction of N-methylation and reduction of one carbonyl of phthalimide,then reacting with triphenylphosphine tetrafluoroborate at room temperature,finally,(2-methyl-3-oxoisoindolin-1-yl)triphenylphosphonium tetrafluoroborate was obtained,which shows solid state and stays stable in air.Meanwhile,under the condition of room temperature,this compound could react with aldehydes(aliphatic aldehydes and aromatic aldehydes)by Wittig olefination to product isoindolinone derivatives with yield 35%~91%.The optimal condition was divided into two parts: For the electron-rich aldehydes,t-BuOK as base and anhydrous THF as solvent for stirring 3hours at room temperature;For the electron-deficient aldehydes,DBU and CH3 CN as base and solvent,respectively,at room temperature for stirring overnight.We also have found that some diacarbonyl compounds with aldehyde group could react with 2-(diphenylphosphino)benzalcohol and triphenylphosphine tetrafluoroborate in THF solvent,at room temperature for stirring overnight,forming cyclic ?-alkoxyphosphonium from the aldehyde group.Meanwhile,under the condition of K2CO3 as base and DMSO/CH3CN(10/1)as solvent,at room temperature,the polycyclic aromatic compound containing vinyl ether fraction with yields of 30%-84% was prepared by conducting intramolecular Wittig olefination with the other carbonyl.