Supramolecular Phthalimide Networks Via Tandem Diels–Alder Reaction–Aromatization Using Biomass-Derived Furanic Dienes

The design and synthesis of phthalimide derivatives are important goals for applications in fields such as pharmaceutical science and optoelectronics. In the present study, a facile and convenient synthetic pathway (no heat or acid/catalyst needed) is devised to produce phthalimides from a biomass-derived furan by directly introducing an N-carbamate group at the C-2 position of the furan ring via thermal Curtius rearrangement. The electron-donating N-carbamate group increases the energy level of the highest occupied molecular orbital of the furan diene, resulting in a significant increase of the rate of the Diels–Alder reaction with maleimide compared to the conventional furfuryl furan. Interestingly, the Diels–Alder adduct smoothly undergoes aromatization (dehydration) to generate the phthalimide motif. It is shown that the biomass-derived phthalimides can produce supramolecular gels and act as sensors of basic anions like F⁻ and CN⁻. The novel synthetic pathway to phthalimide derivatives from a biomass-derived furan can potentially be used to develop novel phthalimide motifs for a variety of applications.