Intermolecular Diels-Alder Cycloadditions of Furfural-Based Chemicals from Renewable Resources: A Focus on the Regio- and Diastereoselectivity in the Reaction with Alkenes

Abstract

A recent strong trend toward green and sustainable chemistry has promoted the intensive use of renewable carbon sources for the production of polymers, biofuels, chemicals, monomers and other valuable products. The Diels-Alder reaction is of great importance in the chemistry of renewable resources and provides an atom-economic pathway for fine chemical synthesis and for the production of materials. The biobased furans furfural and 5-(hydroxymethyl)furfural, which can be easily obtained from the carbohydrate part of plant biomass, were recognized as “platform chemicals” that will help to replace the existing oil-based refining to biorefining. Diels-Alder cycloaddition of furanic dienes with various dienophiles represents the ideal example of a “green” process characterized by a 100% atom economy and a reasonable E-factor. In this review, we first summarize the literature data on the regio- and diastereoselectivity of intermolecular Diels-Alder reactions of furfural derivatives with alkenes with the aim of establishing the current progress in the efficient production of practically important low-molecular-weight products. The information provided here will be useful and relevant to scientists in many fields, including medical and pharmaceutical research, polymer development and materials science.

Diels–Alder Cycloadditions of Bio-Derived Furans with Maleimides as a Sustainable «Click» Approach towards Molecular, Macromolecular and Hybrid Systems

“…The literature data on the diastereoselectivity of the DA reactions between the most common biobased furans and N-alkyl or N-aryl maleimides are summarized in Tables 1 and 2. Based on these data, some typical patterns for the furan/alkene DA reaction [16] were also found for DA reactions with maleimides as dienophiles. An important parameter of the fmDA reaction that should be taken into account in the development of bioactive compounds is diastereoselectivity, because endo and exo diastereomers can exhibit different biological activity [31].…”

“…The literature data on the diastereoselectivity of the DA reactions between the most common biobased furans and N-alkyl or N-aryl maleimides are summarized in Tables 1 and 2. Based on these data, some typical patterns for the furan/alkene DA reaction [16] were also found for DA reactions with maleimides as dienophiles. also possesses strong biological activity (Figure 2) [24][25][26][27][28][29].…”

“…The general routes of applications include the synthesis of aliphatic or aromatic cyclic products, biologically active compounds, monomers and polyfunctional scaffolds. Reductions in the double bond in the furan-derived oxanorbornenes is a route to oxanorbornanes, structural analogs of the bioactive small molecules cantharidin (natural terpenoid isolated from Spanish fly blister beetles) and its synthetic analogs norcantharidin and norcantharimides, which Several recent reviews covered the scientific literature regarding the development of functional or dynamic macromolecular systems employing the fmDA approach [19][20][21]; other reviews provided detailed information about the reactivity of biobased furans in DA cycloadditions [16,22,23]; however, in the context of fmDA reactions, these coverages are not comprehensive or need updating. In this review, we briefly survey recent research trends in the application of the furan/maleimide-based «click» methodology for the production of functional or dynamic molecular, biomolecular and macromolecular systems.…”

“…Electron-poor dienophiles (particularly maleimides) showed high activity in DA cycloadditions with many biobased furans. Some of these reactions proceed efficiently under solvent-free and non-catalytic conditions [16]. The DA reaction of a furanic diene and maleimide dienophile results in the formation of oxabicyclic core (oxanorbornene) as a single diastereomer or as a mixture of the kinetically favored endo form and the more thermodynamically stable exo product.…”

“…Due to its high efficiency, excellent selectivity, 100% atom economy and the biobased nature of most of the furanic substrates, the fmDA reaction may be considered as a sustainable «click» approach for the production of functional or dynamic molecular, biomolecular and macromolecular systems (Figure 1). Several recent reviews covered the scientific literature regarding the development of functional or dynamic macromolecular systems employing the fmDA approach [19][20][21]; other reviews provided detailed information about the reactivity of biobased furans in DA cycloadditions [16,22,23]; however, in the context of fmDA reactions, these coverages are not comprehensive or need updating. In this review, we briefly survey recent research trends in the application of the furan/maleimide-based «click» methodology for the production of functional or dynamic molecular, biomolecular and macromolecular systems.…”