Derivatization of Natural Polymers and Their Derivatives Through Multicomponent Reactions

The ever-growing ecological awareness coerces scientists to employ more sustainable resources, such as natural polymers and their derivatives. However, common derivatization methods often produce persistent by-products, employ harsh solvents and/or coupling agents, thus negatively impacting the environmental footprint of the final materials. In contrast, multicomponent reactions (MCRs) offer significant advantages because of their good atom economy and structural diversity, all in a “one-pot” manner and without coupling agents. Because MCRs fulfill some criteria of green chemistry, they are suitable for the modification of natural polymers and their derivatives. In the present review, we compile and discuss all the studies combining MCRs with natural polymers and their derivatives. This work is separated into isocyanide-based MCRs (Passerini, Ugi) and other reagents-based MCRs (Hantzsch, Biginelli, Mannich, Kabachnik-Fields, Debus-Radziszewski). For each MCRs, its details and mechanism are described, along with its versatility and sustainability. The polymer modified by the MCRs are then developed in connection with the end-uses. Additionally, we provide further insights into the use of aqueous medium and more innocuous reagents, the need for green metrics and the adoption of emerging synthetic techniques. An extensive database of all cited articles is provided in supplementary information, to assist MCRs and natural polymers researchers.