The acetosolv extraction, allylation and subsequent cross-linking of wheat straw lignin to thermoset biomaterials is herein described. The extraction temperature proved to be of great importance for the quality of the resulting lignin, with moderate temperature being key for preservation of β-O-4’ linkages. The allylation of the acetosolv lignin was carried out using three different synthetic strategies, resulting in selective installation of either benzylic or phenolic allyl ethers, or unselective allylation of various hydroxyl groups via etherification and carboxyallylation. The different allylation protocols employed either allyl alcohol, allyl chloride, or diallylcarbonate as allyl precursors, with the latter resulting in the highest degree of functionalization. Selected allylated acetosolv lignins were cross-linked using a thiol-ene approach and the lignin with the highest density of allyl groups was found to form a cross-linked thermoset material with properties comparable to kraft lignin-based analogues.

An efficient reaction at the counter electrode is of key importance for the success of net oxidative and net reductive electrochemical transformations. For electrooxidative processes, cathodic proton reduction to H 2 serves as the benchmark counter reaction. In contrast, net reductive electrochemical transformations have less attractive oxidative counter reactions to choose from and commonly rely on dissolution of a sacrificial anode that effectively results in stoichiometric metal consumption for the processes. In this study, we demonstrate that anodic borohydride oxidation has great potential to successfully replace the use of such sacrificial anodes for a variety of electroreductive organic transformations. This anodic transformation effectively serves as the inverse of cathodic proton reduction, producing H 2 using inert carbon‐based electrode materials.

Alcohols are highly common organic compounds but remain scarce as alkyl donors in synthetic procedures. Here, we describe an electrochemical procedure for their deoxygenative cross-electrophile coupling with hydrosilanes, furnishing organosilane products in good to excellent yields. Mechanistic studies provide insights into the operating pathways of this semi-paired electrolytic transformation, suggesting that silyl ethers are likely reaction intermediates. Furthermore, a unified mechanistic proposal is presented that accounts for observed reactivity differences with analogous deoxygenative electrocarboxylation.

During the last decade, electrosynthesis has emerged as a highly useful synthetic strategy to access complex organic compounds via intermediate radical species. In the context of carbohydrates, electrochemically driven methods have primarily been used to furnish oxocarbenium ion intermediates for glycosylation reactions. Here, we outline a selection of transformations that take off from this established activation mode and provide new routes to structurally diverse glycan-based compounds under net-oxidative, net-reductive and paired electrolytic conditions.

Hole scavenger plays a crucial role in the photocatalytic hydrogen evolution reaction (HER), yet the principle guiding its selection remains controversial. In our study, we evaluate the photocatalytic HER performance of ZnIn2S4 (ZIS) with ten commonly used hole scavengers, and surprisingly find that the HER efficiency is dependent on the coordination interaction between the hole scavenger and the photocatalyst, rather than the commonly recognized redox potential of the scavengers. This coordination interaction can be quantitatively interpreted using the adsorption energy (AE) as a key metric. Notably, a scaling relationship is established between the calculated AE and the experimentally observed photocatalytic H2 evolution rate (Hrate). Among the ten investigated hole scavengers, triethanolamine demonstrates the strongest coordination interaction with ZIS, leading to the highest photocatalytic Hrate of 226.67 μmol h–1. As such, this work offers a valuable guideline for the rational selection of hole scavengers in a given photocatalytic system.

Titanium is an earth abundant metal with low toxicity that is able to form complexes that mediate a wide range of organic transformations in both polar and radical manifolds. In context of the latter, the use of Ti-catalysts in electrosynthesis is surprisingly underexplored, considering the great potential for electrochemical (re)generation of low-valent and catalytically active species. To spur further innovation in the field, this Review provides an overview of the current literature and discusses the limitations and possibilities for electrochemically driven Ti-catalysis.

Herein, we present an electrochemical desulfurative protocol for the formation of alkyl boronic esters from thioethers. The paired electrolytic transformation utilizes HBpin as coupling partner and proceeds with inert electrodes. The transformation features mild conditions, broad substrate scope and excellent functional group tolerance, as illustrated by late-stage functionalization of pharmaceutical compounds and natural products. Furthermore, the protocol is scalable, successfully producing gram quantities of borylated product.

Zirconocene triflate is a powerful moisture-tolerant catalyst for activation of C O bonds in carboxylic acids and alcohols in the absence of water scavenging techniques. Herein, an overview of the use of this robust metal complex for direct amidation, esterification, and etherification is presented, along with a discussion on mechanistic aspects of the transformations and the catalyst class.

Alcohols are one of the most common organic compound classes among natural and synthetic products. Thus, methods for direct removal of C−OH groups without the need for wasteful pre-functionalization are of great synthetic interest to unlock the full synthetic potential of the compound class. Herein, electroreductive C−OH bond activation and subsequent deoxygenative C−H and C−C bond formation of benzylic and propargylic alcohols are demonstrated along with mechanistic insights. Experimental and theoretical studies indicate that the reductive C−OH bond cleavage furnishes an open shell intermediate that undergoes a radical-polar crossover to the corresponding carbanion that subsequently undergoes protonation to furnish alkane products. Furthermore, we demonstrate that the carbanion can be trapped with CO2 to form arylacetic acids. The cathodic transformations are efficiently balanced by the anodic oxidation of sub-stoichiometric borohydride additives, a strategy that serves as a highly attractive alternative to the use of sacrificial metal anodes.