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A catalytic domino, three-component reaction has been developed for the transformation of carbon dioxide into functionalized six-membered cyclic carbonates. The catalytic process combines an initial carboxylative cyclization of β-epoxy alcohols followed by an oxa-Michael reaction affording an unparalleled scope of heterocyclic structures. The wide range of functional groups, including free-alcohols, empowers the access to a range of products including C 11 -oxo-based bicyclic heterocycles. The versatility of these functionalized carbonates is further complemented by a series of synthetic diversifications. Control experiments are consistent with the first step of this domino process being promoted by a binary Lewis acid/base catalyst, while the second stage only requires catalytic base., (© 2023 Wiley‐VCH GmbH.)

Conversion of β-elemene into new β-elemene dicarbonates through epoxidation and halide salt-catalyzed CO 2 cycloaddition reactions is reported. Step-growth polyaddition of this dicarbonate to five different, commercial diamines was investigated under neat conditions at 150 °C yielding non-isocyanate-based low molecular weight oligo(hydroxyurethane)s with 1.3≤M n ≤6.3 kDa and 1.3≤Ð≤2.1, and with glass transition temperatures ranging from -59 to 84 °C. The preparation of one selected polyhydroxyurethane material, obtained in the presence of Jeffamine® D-2010 was scaled-up to 43 g. The latter, when combined in a formulation using Irgacure® 2100 and Laromer® LR 9000 allowed the preparation of coatings that were analyzed with several techniques showing the potential of these biobased oligourethanes towards the preparation of commercially relevant materials., (© 2022 The Authors. ChemSusChem published by Wiley-VCH GmbH.)

Glycerol carbonate (GC) has emerged as an attractive synthetic target due to various promising technological applications. Among several viable strategies to produce GC from CO 2 and glycerol and its derivatives, the cycloaddition of CO 2 to glycidol represents an atom-economic an efficient strategy that can proceed via a halide-free manifold through a proton-shuttling mechanism. Here, it was shown that the synthesis of GC can be promoted by bio-based and readily available organic salts leading to quantitative GC formation under atmospheric CO 2 pressure and moderate temperatures. Comparative and mechanistic experiments using sodium citrate as the most efficient catalyst highlighted the role of both hydrogen bond donor and weakly basic sites in the organic salt towards GC formation. The citrate salt was also used as a catalyst for the conversion of other epoxy alcohols. Importantly, the discovery that homogeneous organic salts catalyze the target reaction inspired us to use metal alginates as heterogeneous and recoverable bio-based catalysts for the same process., (© 2022 Wiley-VCH GmbH.)

Biobased epoxy-derived raw materials will be essential for future coating and adhesive designs in industry. Here, a facile approach is reported towards the incorporation of limonene into an epoxy-functionalized polycarbonate and its crosslinking with a polyamine curing agent to obtain a thermoset material. For the first time, a solvent-borne adhesive with excellent film-forming, mechanical and adhesion strength properties is described., (© 2022 Wiley-VCH GmbH.)

The unparalleled potential of substrate-induced reactivity modes in the catalytic conversion of carbon dioxide and alcohol or amine functionalized epoxides is discussed in relation to more conventional epoxide/CO 2 coupling strategies. This conceptually new approach allows for a substantial extension of the substitution degree and functionality of cyclic carbonate/carbamate products, which are predominant products in the area of nonreductive CO 2 transformations. Apart from the creation of an advanced library of CO 2 -based heterocyclic products and intermediates, also the underlying mechanistic reasons for this novel reactivity profile are debated with a prominent role for the design and structure of the involved catalysts., (© 2020 Wiley-VCH GmbH.)

In this series of articles, the board members of ChemSusChem discuss recent research articles that they consider of exceptional quality and importance for sustainability. This entry features Prof. A. W. Kleij, who discusses the use of electrosynthesis to advance the regioselective hydrocarboxylation of low-value olefins to afford high-value carboxylic acids using carbon dioxide as reagent. In particular, in a recent breakthrough contribution a general β-carboxylation of aromatic olefins is displayed and as such significantly expands state-of-the-art carboxylation chemistry., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Tertiary allylic alcohols were conveniently converted into either (Z)- or (E)-configured α,β-unsaturated γ-amino acids by treatment with secondary amines under Pd catalysis at ambient conditions. The key to control the stereochemical course of these formal allylic aminations was the presence of a suitable diphosphine ligand, with dppp [1,3-bis(diphenylphosphino)propane, L12] providing high yields and selectivities for the (Z) isomers, whereas the bis[(2-diphenylphosphino)phenyl]ether (DPEPhos) derivative L1' allowed for selective formation of the corresponding (E) isomeric products. This ligand-controlled, stereodivergent protocol thus shows promise for the stereoselective preparation of allylic amine products from a common substrate precursor., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In this series of articles, the board members of ChemSusChem discuss recent research articles that they consider of exceptional quality and importance for sustainability. This entry features Prof. Arjan W. Kleij, who discusses the use of terpenes as raw materials for the synthesis of biobased polyesters and polycarbonates, and the opportunities and challenges that lie ahead for these renewable polymers in the area of material science, trying to meet the requirements of a circular economy., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Catalytic ring-opening of bio-sourced non-strained lactones with aromatic amines can offer a straightforward, 100 % atom-economical, and sustainable pathway towards relevant N-aryl amide scaffolds. Herein, the first general, metal-free, and highly efficient N-aryl amide formation is reported from poorly reactive aromatic amines and non-strained lactones under mild operating conditions using an organic bicyclic guanidine catalyst. This protocol has high application potential as exemplified by the formal syntheses of drug-relevant molecules., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We report a comparative study on the activity of a series of fifteen binary catalysts derived from various reported aluminum-based complexes. A benchmarking of their initial rates in the coupling of various terminal and internal epoxides in the presence of three different nucleophilic additives was carried out, providing for the first time a useful comparison of activity metrics in the area of cyclic organic carbonate formation. These investigations provide a useful framework for how to realistically valorize relative reactivities and which features are important when considering the ideal operational window of each binary catalyst system., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Out of thin air: In this Editorial, the Guest Editors introduce a Special Issue on Carbon Dioxide Conversion Catalysis, discuss its importance in modern chemical processes, and highlight a few examples of its use in industry, such as the synthesis of cyclic carbonates and the conversion of CO 2 into fuels., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A detailed study on the mechanism for the alternating copolymerization of cyclohexene oxide (CHO) and CO 2 mediated by an [Al{amino-tri(phenolate)}]/NBu 4 I binary catalyst system was performed by using DFT-based methods. Four potential mechanisms (one monometallic and three bimetallic) were considered for the first propagation cycle of the CHO/CO 2 copolymerization. The obtained Gibbs free energies provided a rationale for the relative high activity of a non-covalent dimeric structure formed in situ and thus for the feasibility of a bimetallic mechanism to obtain polycarbonates quantitatively. Gibbs free energies also indicated that the alternating copolymerization was favored over the cyclic carbonate formation., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The challenging coupling of highly substituted terpene oxides and carbon dioxide into bio-based cyclic organic carbonates catalyzed by Al(aminotriphenolate) complexes is reported. Both acyclic as well as cyclic terpene oxides were used as coupling partners, showing distinct reactivity/selectivity behavior. Whereas cyclic terpene oxides showed excellent chemoselectivity towards the organic carbonate product, acyclic substrates exhibited poorer selectivities owing to concomitant epoxide rearrangement reactions and the formation of undesired oligo/polyether side products. Considering the challenging nature of these coupling reactions, the isolated yields of the targeted bio-carbonates are reasonable and in most cases in the range 50-60 %. The first crystal structures of tri-substituted terpene based cyclic carbonates are reported and their stereoconnectivity suggests that their formation proceeds through a double inversion pathway., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A variety of cavitand-based polyphenols was prepared from cheap and accessible aldehyde and resorcinol/pyrogallol reagents to give the respective resorcin[4]- or pyrogallol[4]arenes. The preorganization of the phenolic units allows intra- and intermolecular hydrogen bond (HB) networks that affect both the reactivity and stability of these HB-donor catalysts. Unexpectedly, we found that the resorcin[4]arenes show cooperative catalysis behavior compared to the parent resorcinol in the catalytic coupling of epoxides and CO2 with a significantly higher turnover. At elevated reaction temperatures, the resorcin[4]arene-based catalyst 3 d displays the best catalytic performance with very high turnover numbers and frequencies, combining increased reactivity and stability compared to pyrogallol, and an ample substrate scope. This type of polyphenol structure thus illustrates the importance of a new, highly competitive organocatalyst design to devise sustainable CO2 conversion processes., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A binary catalyst system based on tannic acid/NBu4X (X=Br, I) is presented as a highly efficient organocatalyst at very low catalyst loading for the coupling of carbon dioxide and functional oxiranes to afford organic carbonates in good yields. The presence of multiple polyphenol fragments within the tannic acid structure is considered to be beneficial for synergistic effects that lead to higher stabilization of the catalyst structure during catalysis. The observed turnover frequencies (TOFs) exceed 200 h(-1) and are among the highest reported to date for organocatalysts in this area of CO2 conversion. This organocatalyst system presents a useful, readily available, inexpensive, and, above all, reactive alternative for most of the metal-based catalyst systems reported to date., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The atom-efficient reaction of CO2 with a variety of epoxides has been efficiently achieved employing iron pyridylamino-bis(phenolate) complexes as bifunctional catalysts. The addition of a Lewis base co-catalyst allowed significant reduction in the amount of iron complex needed to achieve high epoxide conversions. The possibility of controlling the selectivity of the reaction towards either cyclic carbonate or polycarbonate was evaluated. An efficient switch in selectivity could be achieved when cyclic epoxides such as cyclohexene oxide and the seldom explored 1,2-epoxy-4-vinylcyclohexane were used as substrates. The obtained poly(vinylcyclohexene carbonate) presents pending vinyl groups, which allowed post-synthetic cross-linking by reaction with 1,3-propanedithiol. The cross-linked polycarbonate displayed a substantial increase in the glass transition temperature and chemical resistance, thus opening new opportunities for the application of these green polymers., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The use of phenolic compounds as organocatalysts is discussed in the context of the atom-efficient cycloaddition of carbon dioxide to epoxides, forming useful cyclic organic carbonate products. The presence and cooperative nature of adjacent phenolic groups in the catalyst structure results in significantly enhanced catalytic efficiencies, allowing these CO(2) fixation reactions to operate efficiently under virtually ambient conditions. The cooperative effect has also been studied by computational methods. Furthermore, when the cycloaddition reactions are carried out on a larger scale and under solvent-free conditions, further enhancements in activity are observed, combined with the advantageous requirement of reduced loadings of the binary organocatalyst system. The reported system is among one of the mildest and most effective metal-free catalysts for this conversion and contributes to a much more sustainable development of organic carbonate production; this feature has not been the main focus of previous contributions in this area., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)