Furan Oxidations in Organic Synthesis: Recent Advances and Applications

Abstract

Oxidation reactions of several furan derivatives as effective methods for the preparation of key synthetic intermediates are reviewed. Depending on the oxidizing reagent the furan ring can be considered as a C-1 or C-4 synthon, which upon different conditions leads to 1,4-dicarbonyl compounds, carboxylic acids, pyranones or butenolides.

(E)-4-(3-Phenylisoxazol-5-yl)but-3-en-2-one

“…Oxime 2c was synthesized via the reaction of furfuryl ketone 5 with hydroxylamine hydrochloride, and sodium acetate in ethanol. The subsequent furan ring opening-isoxazole ring closure reaction of 2c under oxidative conditions [15,16] provided the target 4-(3-phenylisoxazol-5-yl)but-3-en-2-one 4c in high yield as a mixture of (E,Z)-isomers (Scheme 2). Isoxazole (E)-4c was obtained in a pure form through iodine-mediated isomerization [17] and fully characterized (Scheme 3).…”

Homogeneous Catalyzed Valorization of Furanics: A Sustainable Bridge to Fuels and Chemicals

“…Those chemicals can be produced via different processes. For example, the typical reactions that the furanic aldehyde functionality can undergo are reduction to alcohols by H 2 or by hydrogen transfer (Meerwein-Ponndorf-Verley reduction) [47], decarbonylation [48], reductive amination to amines [49], oxidation to carboxylic acid [50], acetalization [51], aldol and Knoevenagel condensations [52], acylation, and Grignard reactions [53]. The second reactive functionality is the hydroxyl group that can undergo hydrogenolysis of the C−O bond, oxidation to an aldehyde or acid, etherification, acetalization, esterification, and halogenation reactions [54].…”

Syntheses and applications of furanyl-functionalised 2,2’:6’,2’’-terpyridines

“…In fact, the furan ring can readily undergo oxidative cleavage under various conditions, thus providing an interesting route to carboxylates [35]. In the case of tpys, oxidation of the furanyl ring was performed by using potassium permanganate in a basic reaction medium, followed by acidification to recover the acids.…”