Targeting Nitrogenated Aromatics: Tandem Diels-Alder/Aromatization Reaction of Chitin-Derived Furans

Abstract

The application of biomass-derived furans in sequential Diels-Alder (DA)/aromatization reactions is a promising approach for the preparation of aromatic compounds with different substitution patterns. In this work, we addressed the challenge of using chitin-derived furans, 3-acetamido-5-ethylfuran (3A5EF) and 3-Acetamido-5-(1-hydroxyethyl) furan (3A5HF), for the formation of 4-Acetylaminophthalimides and other N-containing aromatic compounds. The transformation is carried out sequentially and involves the formation of the DA adduct, 7-oxa-norbornene, which in an acid/acetylating medium undergoes a dehydration/aromatization reaction, providing the compounds in yields ranging from 16-80%. To the best of our knowledge, this is the first report involving a chitin derivative for the formation of 4-Acetylaminophthalimides, which is the first step towards expanding the toolbox of chitin-derived furans in the synthesis of nitrogenated aromatic compounds with the nitrogen atom directly attached to the benzene ring.

π-Facial selectivity in the Diels–Alder reaction of glucosamine-based chiral furans and maleimides

“…22 The DA reaction has been applied extensively to carbohydrate-derived furans. [23][24][25][26] This normally requires that these typically electron poor dienes are first converted into more electron rich derivatives. 27,28 However, very recently examples of the direct Diels-Alder reaction with carbohydrate-based furans have been reported.…”