Concatenating Microbial, Enzymatic, and Organometallic Catalysis for Integrated Conversion of Renewable Carbon Sources.

The chemical industry can now seize the opportunity to improve the sustainability of its processes by replacing fossil carbon sources with renewable alternatives such as CO, biomass, and plastics, thereby thinking ahead and having a look into the future. For their conversion to intermediate and final products, different types of catalysts-microbial, enzymatic, and organometallic-can be applied. The first part of this review shows how these catalysts can work separately in parallel, each route with unique requirements and advantages.

Interdisciplinary development of an overall process concept from glucose to 4,5-dimethyl-1,3-dioxolane via 2,3-butanediol.

To reduce carbon dioxide emissions, carbon-neutral fuels have recently gained renewed attention. Here we show the development and evaluation of process routes for the production of such a fuel, the cyclic acetal 4,5-dimethyl-1,3-dioxolane, from glucose via 2,3-butanediol. The selected process routes are based on the sequential use of microbes, enzymes and chemo-catalysts in order to exploit the full potential of the different catalyst systems through a tailor-made combination.

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.

Organic Dye-Catalyzed Atom Transfer Radical Addition-Elimination (ATRE) Reaction for the Synthesis of Perfluoroalkylated Alkenes.

An atom transfer radical addition elimination (ATRE) reaction of terminal alkenes with perfluoroalkyl halides under visible light is described. The photoredox catalysis with Eosin Y provides perfluoroalkenes in good yields. The reaction has been utilized for the late stage perfluoroalkenylation of an estrone-derived alkene.

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.