A direct Diels-Alder reaction of chitin derived 3-acetamido-5-acetylfuran

Abstract

The Diels-Alder (DA) reaction of biomass derived furans is an emerging technology for the preparation of new molecular entities and “drop-in” commodity chemicals. In this work, we address the challenge of the direct use of electron-poor furanic platforms as dienes through the use of an unexplored chitin derived furan, 3-acetamido-5-acetylfuran (3A5AF). The 3-acetamido group promoted a remarkable increase in the kinetics of the DA reaction, allowing for the preparation of 7-oxanorbornenes (7-ONBs) at 50 °C. Partial hydrolysis of enamide to hemi-acylaminals was possible upon fine-tuning of the reaction conditions, disabling retro-DA processes. Finally, the DA reaction of the reduced form of 3A5AF allowed quantitative formation of 7-ONBs under aqueous conditions after 10 minutes. Certainly, these are the first steps for expanding the toolbox of chitin derived 3A5AF as a diene.