Robby Vroemans

Nature, Published online: 09 December 2021; doi:10.1038/d41586-021-03650-9

Abstract

C−H Activation by transition metals has revolutionized the field of modern synthetic organic chemistry thereby enabling efficient and atom-economical construction of complex organic frameworks in reduced number of steps. Various ways are being explored in order to maximize efficiency of the approach and construct previously unknown molecules. The major challenge in this aspect is the ubiquitous presence of C−H bond in an organic molecule that demands sophistication to achieve site-selective functionalization. Directing group approach provided the most viable solution which operates through formation of a thermodynamically preferred metallacycle. Although, five and six membered metallacycles are known to be thermodynamically most favorable, there exists ingenious methodologies that operates through a four-membered metallacycle in order to achieve site-selectivity. In this review article, we summarize the C−H activation reactions evidenced to proceed via four-membered metallacycle intermediate to achieve synthetically relevant transformations.

Molecules, Vol. 26, Pages 7363: 5-Dodecanolide, a Compound Isolated from Pig Lard, Presents Powerful Anti-Inflammatory Properties

Molecules doi: 10.3390/molecules26237363

Authors: Xavier Capó Miquel Martorell Josep A. Tur Antoni Sureda Antoni Pons

Background: Pork lard (PL) is traditionally used as an anti-inflammatory agent. We propose to demonstrate the anti-inflammatory properties of PL, and elucidate which compounds could be responsible for the anti-inflammatory effects. Methods: The anti-inflammatory effects of PL were tested in a rat model of zymosan-induced hind paw inflammation. Further, the hydroalcoholic extract from PL was obtained, the composition analyzed, and the anti-inflammatory activity of the extracts and isolated components assayed using immune cells stimulated with lipopolysaccharide (LPS). Results: Applying the ointment on the inflamed rat feet reduced the foot diameter, foot weight, and activities of antioxidant enzymes and inflammatory markers of circulating neutrophils. The main components of the hydroalcoholic extract were 5-dodecanolide, oleamide, hexadecanoic acid, 9-octadecenoic acid, hexadecanamide, and resolvin D1. Conclusions: PL reduces the immune response in an animal model stimulated with zymosan. Hydroalcoholic PL extract and its components (5-Dodecanolide, Oleamide, and Resolvin D1) exerted an anti-inflammatory effect on LPS-stimulated neutrophils and peripheral mononuclear cells reducing the capability to produce TNFα, as well as the activities of antioxidant and pro-inflammatory enzymes. These effects are attributable to 5-dodecanolide, although the effects of this compound alone do not reach the magnitude of the anti-inflammatory effects observed by the complete hydroalcoholic extract.

The interaction of nucleophiles with nitroarenes can result in direct, reversible addition to form σ adducts and products of S_NAr, or in single electron transfer (SET) which usually initiates other processes.

Abstract

Analysis of effects of various parameters on reactions of C, N and O nucleophiles with nitroarenes leads to the conclusion that there are two different major pathways: direct addition leading to substitution of hydrogen or halogens and single electron transfer (SET), leading to other processes. In some, rather rare cases, paramagnetic species generated by SET can combine, resulting in substitution.

Nature Catalysis, Published online: 02 December 2021; doi:10.1038/s41929-021-00710-1

Nature Catalysis, Published online: 02 December 2021; doi:10.1038/s41929-021-00709-8

Nature, Published online: 01 December 2021; doi:10.1038/d41586-021-03572-6

Nature, Published online: 01 December 2021; doi:10.1038/d41586-021-03603-2

The Front Cover illustrates a concept to switch the raw material basis for plasticizer production from fossil to bio-based feedstocks. The bicyclic plasticizers, which were synthesized as target molecules, are accessible from bio-based 2-methylfuran, maleic anhydride and 2-ethylhexanol. Evaluating the performance of this new bio-based plasticizer generation revealed promising plasticizing properties. More information can be found in the Full Paper by R. Otter, A. Liese, H. Gröger et al.

Publication date: 13 January 2022

Source: Chem, Volume 8, Issue 1

Author(s): Wen-Hao Li, Jiarui Yang, Dingsheng Wang, Yadong Li

A fast method for the easy access of 4-amino substituted 3-nitro-phenyl isocyanides was developed under room temperature with moderate to high yields. The products are very reactive in a number of tested typical multicomponent reactions.

Abstract

Isocyanides are important building blocks in organic synthesis; however, their synthesis is time and resource consuming and often unpleasant due to their smelly nature. Diversification of isocyanides can be accomplished by de novo synthesis or from already existing isocyanides. In this work, we report for the first-time isocyanide diversification based on nucleophilic aromatic substitution of suitable precursor isocyanides. The mild conditions allow for easy access to multiple novel isocyanides useful in organic synthesis. The resulting isocyanides are solid and non-noxious, yet react nicely in multicomponent reactions.

A Co single atom is incorporated in a RuO₂ sphere through a one-pot hydrothermal process, as revealed by EXAFS, HRTEM, and AC-STEM. The Co single atoms could tailor the local electronic structure of the bifunctional electrocatalyst for high-performance HER and OER, which significantly reduces the energy barrier, and the catalyst shows the lowest overpotential of 45 mV for HER and 200 mV for OER at a current density of 10 mA cm⁻².

Abstract

The development of highly active and stable bifunctional noble-metal-based electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is a crucial goal for clean and renewable energy, which still remains challenging. Herein, we report an efficient and stable catalyst comprising a Co single atom incorporated in an RuO₂ sphere for HER and OER, in which the Co single atom in the RuO₂ sphere was confirmed by XAS, AC-STEM, and DFT. This tailoring strategy uses a Co single atom to modify the electronic structures of the surrounding Ru atoms and thereby remarkably elevates the electrocatalytic activities. The catalyst requires ultralow overpotentials, 45 mV for HER and 200 mV for OER, to deliver a current density of 10 mA cm⁻². The theoretical calculations reveal that the energy barriers for HER and OER are lowered after incorporation of a cobalt single atom.