Facile synthesis of isoindoline-1,3-diones by palladium-catalyzed carbonylative cyclization of o-bromobenzoic acid and primary amines

摘要

A facile method for the carbonylative cyclization of o-bromobenzoic acid with primary amine using Pd(OAC)_2 as a metal precursor and 1,1'-bis(diphenylpho-sphino)ferrocene (dppf) as a ligand has been developed. The effect of various reaction parameters such as ligand, solvent, base, time and temperature on this cyclization was studied. The optimized protocol was used for a wide variety of substituted aryl amines with different steric and electronic properties, affording the corresponding isoindoline-1,3-diones in good to excellent yields under atmospheric pressure of carbon monoxide at 100℃ within 10 h using 1,4-diazabicyclo[2.2.2]octane (DABCO) as a base. The reaction system finds attractive alternative to the conventional multistep synthetic process and thus represents an effective utilization of carbonylative protocol for synthesis of valuable chemicals.