Effect of substituents and promoters on the Diels–Alder cycloaddition reaction in the biorenewable synthesis of trimellitic acid

)/2 were both suggested to be suitable descriptors for the DA reaction of electron-rich diene and electron-deficient dienophile. Further solvents did not have a significant effect on the activation barrier for DA reaction. In contrast, the presence of a Lewis acid was seen to lower the activation barrier due to the reduction in the FMO gap.