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

Abstract

Furans derived from carbohydrate feedstocks are a versatile class of bio-renewable building blocks and have been used extensively to access 7-oxanorbornenes via Diels-Alder reactions. Due to their substitution patterns these...

Substituted anilides from chitin-based 3-acetamido-furfural

“…Next, we tried the reaction with the less reactive dienophile ethyl acrylate, which was initially unsuccessful. Based on our experience with Di-HAF , 27 we assumed that the Diels–Alder reaction with ethyl acrylate was reversible and the retro reaction dominated. Reversibility in Diels–Alder reactions with furans is a common phenomenon.…”

“…16,17 From this amino-sugar the platform chemicals dihydroxyethyl acetamidofuran ( Di-HAF ) 18 and 3-acetamido-5-acetylfuran ( 3A5AF ) 19–21 can be accessed through a dehydration process. These furans exhibit a rich reactivity profile 22,23 and have been employed in rearrangement reactions, 24,25 cyclo-additions 26,27 and as synthetic building blocks for the preparation of various alkaloids. 28,29…”

“…16,17 From this amino-sugar the platform chemicals dihydroxyethyl acetamidofuran (Di-HAF) 18 and 3-acetamido-5-acetylfuran (3A5AF) [19][20][21] can be accessed through a dehydration process. These furans exhibit a rich reactivity profile 22,23 and have been employed in rearrangement reactions, 24,25 cyclo-additions 26,27 and as synthetic building blocks for the preparation of various alkaloids. 28,29 While the formation of an anilide side product was already identified during development of the synthesis of 3A5AF, 19 it was only recently that the first targeted synthesis of anilides from a chitin-derived furan was published by Pastre et al (Scheme 1A).…”

Insights into Endo/Exo Stereopreference in Diels–Alder Cycloadditions of Chitin-Derived Furans

“…18,19 Recently, the first studies were published demonstrating DA cycloaddition with NAG-derived nitrogen-containing furans. Chirality transfer from enantiopure Di-HAF by stereocenterinduced π-facial selectivity was reported by Minnaard et al 20 The group of Gomes 21 used 3A5AF and N-[5-(1-hydroxyethyl)-3-furanyl]acetamide (HEFA) as dienes and focused on expanding the scope of DA cycloadditions of 3A5AF with several dienophiles. The focus of this seminal report was on achieving improved yields and determining the scope of the reaction and the formation of the hydration side product.…”

Expanding Heteroaromatic and 2-Aminosugar Chemical Space Accessible from the Biopolymer Chitin

“…We recently demonstrated that the inherent chirality present in chitin can be transferred to the natural product epi-leptosphaerin A via the chiral pool di-HAF platform [22]. Other research groups have shown that 3A5AF (and derivatives) [23,24] and di-HAF [25] can serve as dienes in the Diels-Alder reaction, while 3A5F has shown significant promise as a platform chemical, including as a bioconjugation handle for N-cysteine's modification [13].…”