In this review, we provide a concise analysis of internal catalysis as an attractive design principle to combine chemical robustness with reactivity in dynamic covalent chemistry applications and a material context.

During the previous decade, many popular chemical reactions used in the area of "click" chemistry and similarly efficient "click-inspired" reactions have been applied for the design of sequence-defined and, more generally, sequence-controlled structures. This combination of topics has already made quite a significant impact on scientific research to date and has enabled the synthesis of highly functionalized and complex oligomeric and polymeric structures, which offer the prospect of many exciting further developments and applications in the near future. This minireview highlights the fruitful combination of these two topics for the preparation of sequence-controlled oligomeric and macromolecular structures and showcases the vast number of publications in this field within a relatively short span of time. It is divided into three sections according to the click-(inspired) reaction that has been applied: copper-catalyzed azide-alkyne cycloaddition, thiol-X, and related thiolactone-based reactions, and finally Diels-Alder-chemistry-based routes are outlined, respectively.

Phthalate monoesters (PMEs) were recently introduced as a simple dynamic covalent bond for implementation in covalent adaptable networks (CANs), which undergo rapid transesterifications in the absence of catalysts, due to...

Dynamic sequence‐defined oligomers carrying a chemically written pin code are obtained through a strategy combining multicomponent reactions with the thermoreversible addition of 1,2,4‐triazoline‐3,5‐diones (TADs) to indole substrates. The precision oligomers are specifically designed to be encrypted upon heating as a result of the random reshuffling of the TAD‐indole covalent bonds within the backbone, thereby resulting in the scrambling of the encoded information. The encrypted pin code can eventually be decrypted following a second heating step that enables the macromolecular pin code to be deciphered using 1D electrospray ionization‐mass spectrometry (ESI‐MS). The herein introduced concept of encryption/decryption represents a key advancement compared with current strategies that typically use uncontrolled degradation to erase and tandem mass spectrometry (MS/MS) to analyze, decipher, and read‐out chemically encrypted information. Additionally, the synthesized macromolecules are coated onto a high‐value polymer material, which demonstrates their potential application as coded product tags for anti‐counterfeiting purposes.

Sequence-defined macromolecules of high molecular weight are synthesised by the combination of click chemistry with multicomponent reactions. The synthesis is performed on solid phase as well as in solution to directly compare the two approaches.

A strategy for the synthesis of sequence-defined oligomers using a selective side-group insertion approach making use of thiophenol-catalyzed amidation reactions is herein reported. In this context, a new thiolactone-based, multistep, iterative protocol is designed, utilizing thioacrylates in combination with solid-phase synthesis for step-by-step growth, resulting in sequence-defined oligomers. Sequence definition and structure variation are introduced by substituting the thioacrylate side groups with a wide variety of amines. The step-by-step growth of the oligomers is followed by liquid chromatography-mass spectrometry and high-resolution mass spectroscopy to determine both conversion and purity.

An automated, iterative protocol for the synthesis of multifunctional, sequence‐defined oligo‐urethane‐amides using thiolactone chemistry is reported. Here, sequenced functionalization of the backbone is easily introduced using commercially available primary amines. The chemistry is carried out on solid phase using different supports for better optimization of the synthetic protocol and in order to demonstrate the versatility of the approach. This technique is very effective for iterative synthesis and solid‐phase chemistry and enables the exploration of full automation of this approach using a robotic peptide synthesizer. As a result, this automated protocol allows for the synthesis of a sequence‐defined nonamer of high purity.

This study combines vinylogous urethane (VU) and beta-amino ester chemistry for the synthesis of covalent adaptable networks (CANs). The resulting CANs are synthesised using a range of diacetoacetates and commercially...