In order to understand the vital role of the imide substituent, a systematic theoretical DFT study at the PCM/B3LYP/6-31+G(d) level was carried out. We found that substituents at the nitrogen atom of epoxyimides exerted remarkable effects on the regioselectivity in the ethanolysis reaction, based on the solvent effects and intramolecular electronic interactions. Particularly, the preference for the
Under mechanochemical milling conditions, Diels-Alder cycloaddition of cyclopentadiene with maleic anhydride and maleimide derivatives proceeded very smoothly, affording endo-norbornenes exclusively in quantitative yield. All the transformations were accomplished at room temperature without using any catalyst or organic solvent, thus the workup and purification procedure is very simple. Control experiments on traditional and other tentative conditions were also investigated.
You can append on me! Porphyrin‐appended polynorbornenes derived from 5,6‐endo‐fused N‐arylpyrrolidenonorbornenes have been shown to have coherentlyaligned pendant groups that exhibit exciton coupling and fluorescence quenching in the absorption and emission profiles (see figure).
Two methods for the chemoselective alcoholysis of acylureas were developed to generate esters and amides, respectively. In alcoholysis using sodium methoxide in methanol, methoxide attacked the acyl carbonyl to give the corresponding methyl ester. While in alcoholysis using lithium benzyloxide in diethyl ether, benzyloxide attacked the urea carbonyl to give the amide. The chemoselectivity originates in the different chelating abilities of the metals and the polarity of the solvents.