In the presence of a catalyst system consisting of a ruthenium/triphos complex and the Brønsted acid trifluoromethanesulfonimide, mixtures of fatty acids and aliphatic alcohols are converted into the corresponding ethers at 70 bar H2 . The protocol allows the sustainable one-step synthesis of valuable long-chain ether fragrances, lubricants, and surfactants from renewable sources. The reaction protocol is extended to various fatty acids and esters both in pure form and as mixtures, for example, tall oil acids or rapeseed methyl ester (RME). Even the mixed triglyceride rapeseed oil was converted in one step.

A copper(I) catalyst enables the insertion of carbon dioxide into alkyne C-H bonds by using a suitable organic base with which hydrogenation of the resulting carboxylate salt with regeneration of the base becomes thermodynamically feasible. In the presence of catalytic copper(I) chloride/4,7-diphenyl-1,10-phenanthroline, polymer-bound triphenylphosphine, and 2,2,6,6-tetramethylpiperidine as the base, terminal alkynes undergo carboxylation at 15 bar CO and room temperature. After filtration, the ammonium alkynecarboxylate can be hydrogenated to the primary alcohol and water at a rhodium/molybdenum catalyst, regenerating the amine base. This demonstrates the feasibility of a salt-free overall process, in which carbon dioxide serves as a C1 building block in a C-H functionalization.

Various (hetero)arenecarboxylic acids were converted to the corresponding Daugulis amides and nitrated selectively in the ortho-position in the presence of [CuNO3(PPh3)2] and AgNO2 at 50 °C. A microwave-assisted saponification allows regenerating the carboxylate group within minutes, which may then be removed tracelessly by protodecarboxylation, or substituted by aryl- or alkoxy-groups via decarboxylative cross-coupling.

A hydroxymethylation of alkynes with carbon dioxide and hydrogen was achieved without producing any salt waste. In a sequential procedure, terminal alkynes are carboxylated followed by hydrogenation of the carboxylate salts formed as intermediates. The gorge symbolizes the gap in pKa at which the two reaction steps usually operate. The key to bridging this gap was to identify a base that, under carefully controlled conditions, is able to mediate both steps and may be recycled. The overall process demonstrates a sustainable use of carbon dioxide as a C1 building block. For more information, see the Communication by L. J. Gooßen et al. on page 6019 ff.

An efficient chelation assisted regioselective C‐H nitration of a variety of arenes and hetero arenes is developed.