Facile Multicomponent Polymerization and Postpolymerization Modification via an Effective Meldrum's Acid‐Based Three‐Component Reaction

Abstract

Providing access to highly diverse polymer structures by multicomponent reactions is highly desirable; efficient Meldrum's acid‐based multicomponent reactions, however, have been rarely highlighted in polymer chemistry. Here, the three‐component reaction of Meldrum's acid, indole, and aldehyde is introduced into polymer synthesis. Direct multicomponent polymerization of Meldrum's acid, dialdehyde, and diindole can perform under mild conditions, resulting in complex Meldrum's acid‐containing polymers with well‐defined structures, and high molecular weights. Additionally, nearly quantitative postpolymerization modification can also perform via this Meldrum's acid‐based multicomponent reaction. These results indicate that Meldrum's acid‐based multicomponent reaction will be a potential tool to prepare novel polymers.

Covalent Materials and Hybrids: From 0D to 3D

“…32 They have used essential oil extracts to prepare ultravioletprotective polymers by multicomponent Biginelli reaction. Conversely, a proline-catalyzed three-component reaction of Meldrum's acid, aldehydes, and indole was reported by Meng et al 33…”

The Molecular Diversity Scope of Meldrum's Acid in Multicomponent Reactions

“…The reaction of Meldrum's acid 1, indole 33 or 33', and aldehyde 13 or 13' using L-proline generated indole derivatives 157 or highyield polymer 158 (Scheme 71A-B). [72] Synthesis of 5-((1H-indol-3-yl)(aryl)methyl)-2,2-dimethyl-1,3-dioxane-4,6-diones 160 was reported by Szewczyk and co-workers through the MCR between N-methylindole 159, benzaldehydes 13, and Meldrum's acid 1 catalyzed by Lproline in acetonitrile (Scheme 72). [73] A catalyst-free method for the preparation of Knoevenogel-Michael adducts of imidazole derivatives 162 via a three-component reaction of aromatic aldehydes 13 with Meldrum's acid 1 and 2-amino-4-arylimidazoles 161 in refluxing 2-propranol for 3-5 minutes was reported by Lipson and co-workers (Scheme 73).…”

“…The reaction of Meldrum's acid 1 , indole 33 or 33′ , and aldehyde 13 or 13′ using L ‐proline generated indole derivatives 157 or high‐yield polymer 158 (Scheme 71A–B). [72] …”

Room-Temperature Metal-Free Multicomponent Polymerizations of Elemental Selenium toward Stable Alicyclic Poly(oxaselenolane)s with High Refractive Index

“…Elemental selenium, as a byproduct from the metal refinery industry, is stable and possesses low toxicity, which could be an ideal selenium source for the preparation of selenium-containing polymers. Multicomponent polymerizations (MCPs) featuring high efficiency, simple operation, high atom economy, environmental benefit, and great structural diversity of polymer products have been recently developed as powerful tools for the construction of complex polymer structures from simple monomers, − which could realize direct conversion from elemental selenium to selenium-containing polymers . For example, we have successfully developed a series of elemental sulfur/selenium-based MCPs for the high-throughput construction of sulfur/selenium-containing functional polymers such as polythioamides, , polythioureas, and polyselenoureas, which generally enjoy high yields, high molecular weights, unique luminescence properties, and potential applications in gold recovery from electronic wastes or mercury removal.…”