Effective Production of Selected Dioxolanes by Sequential Bio- and Chemocatalysis Enabled by Adapted Solvent Switching.

Most combinations of chemo- and biocatalysis take place in aqueous media or require a solvent change with complex intermediate processing. Using enzymes in the same organic solvent as the chemocatalyst eliminates this need. Here, it was shown that a complete chemoenzymatic cascade to form dioxolanes could be carried out in a purely organic environment.

Efficient Plastic Waste Recycling to Value-Added Products by Integrated Biomass Processing.

The industrial production of polymeric materials is continuously increasing, but sustainable concepts directing towards a circular economy remain rather elusive. The present investigation focuses on the recycling of polyoxymethylene polymers, facilitated through combined catalytic processing of polymer waste and biomass-derived diols. The integrated concept enables the production of value-added cyclic acetals, which can flexibly function as solvents, fuel additives, pharmaceutical intermediates, and even monomeric materials for polymerization reactions.

Ruthenium-Catalyzed Synthesis of Cyclic and Linear Acetals by the Combined Utilization of CO , H , and Biomass Derived Diols.

Herein a transition-metal catalyst system for the selective synthesis of cyclic and linear acetals from the combined utilization of carbon dioxide, molecular hydrogen, and biomass derived diols is presented. Detailed investigations on the substrate scope enabled the selectivity of the reaction to be largely guided and demonstrated the possibility of integrating a broad variety of substrate molecules. This approach allowed a change between the favored formation of cyclic acetals and linear acetals, originating from the bridging of two diols with a carbon-dioxide based methylene unit.

Ruthenium-Catalyzed Synthesis of Dialkoxymethane Ethers Utilizing Carbon Dioxide and Molecular Hydrogen.

The synthesis of dimethoxymethane (DMM) by a multistep reaction of methanol with carbon dioxide and molecular hydrogen is reported. Using the molecular catalyst [Ru(triphos)(tmm)] in combination with the Lewis acid Al(OTf)3 resulted in a versatile catalytic system for the synthesis of various dialkoxymethane ethers. This new catalytic reaction provides the first synthetic example for the selective conversion of carbon dioxide and hydrogen into a formaldehyde oxidation level, thus opening access to new molecular structures using this important C1 source.

Selective Catalytic Synthesis Using the Combination of Carbon Dioxide and Hydrogen: Catalytic Chess at the Interface of Energy and Chemistry.

The present Review highlights the challenges and opportunities when using the combination CO2 /H2 as a C1 synthon in catalytic reactions and processes. The transformations are classified according to the reduction level and the bond-forming processes, covering the value chain from high volume basic chemicals to complex molecules, including biologically active substances. Whereas some of these concepts can facilitate the transition of the energy system by harvesting renewable energy into chemical products, others provide options to reduce the environmental impact of chemical production already in today's petrochemical-based industry.

Ruthenium-catalyzed reductive methylation of imines using carbon dioxide and molecular hydrogen.

The use of the well-defined [Ru(triphos)(tmm)] catalyst, CO2 as C1 source, and H2 as reducing agent enabled the reductive methylation of isolated imines, as well as the direct coupling of amines with aldehydes and the subsequent reductive methylation of the in situ formed imines. The method, which afforded the corresponding N-methyl amines in very good to excellent yields, was also used for the preparation of the antifungal agent butenafine in one step with no apparent waste, thus increasing the atom efficiency of its synthesis.

Palladium-catalyzed direct arylation of luminescent bis-cyclometalated iridium(III) complexes incorporating C^N- or O^O-coordinating thiophene-based ligands: an efficient method for color tuning.

We report the palladium-catalyzed direct 5-arylation of both metalated and nonmetalated thiophene moieties of iridium complexes 2, 3, and 4 with aryl halides via C-H bond functionalization. This method opens new routes to varieties of Ir complexes in only one step, allowing easy modification of the nature of the ligand. The photophysical properties of the new functionalized complexes have been studied by means of absorption and emission spectroscopy.

A straightforward access to photochromic diarylethene derivatives via palladium-catalysed direct heteroarylation of 1,2-dichloroperfluorocyclopentene.

A novel and efficient palladium-catalysed direct di-heteroarylation of 1,2-dichloroperfluorocyclopentene with a variety of heteroarenes is reported, giving rise to 1,2-di(heteroaryl)ylperfluorocyclopentene photochromic compounds. The reaction proceeds with thiazoles, thiophenes or furan derivatives and tolerates various substituents.

Palladium-catalysed direct arylation of a tris-cyclometallated Ir(III) complex bearing 2,2'-thienylpyridine ligands: a powerful tool for the tuning of luminescence properties.

Palladium-catalysed direct 5-arylation of metallated thiophenes of fac-Ir(N^C(3')-thpy)(3) with aryl bromides via C-H bond functionalisation allows the synthesis of a variety of new Ir complexes in only one step (thpyH = 2,2'-thienylpyridine). The method offers simple modification of the nature of the ligand and hence of the photophysical properties of such complexes.

Cyclopentyl methyl ether: an alternative solvent for palladium-catalyzed direct arylation of heteroaromatics.

Some ethers, such as cyclopentyl methyl ether and di-n-butyl ether, which can be considered as "greener" solvents than N,N-dimethylacetamide (DMAc) or DMF, can be advantageously employed for the palladium-catalyzed direct arylation of heteroaromatics. In the presence of such ethers and only 0.5-1 mol % of palladium catalysts at 125-150 °C, the direct 5-arylation of thiazoles, thiophenes, or furans by using aryl bromides as coupling partners proceeds in moderate to high yields.

Efficient ruthenium-catalyzed synthesis of [3]dendralenes from 1,3-dienic allylic carbonates.

Selective elimination from 1,3-dienic allylic carbonates occurs in the presence of a catalytic amount of [Ru(C(5)Me(5))(4,4'-di-Bu(t)-2,2'-bipyridine)(CH(3)CN)]PF(6) and provides efficient access to a variety of [3]dendralenes.