Robby Vroemans

Synlett
DOI: 10.1055/a-1672-7285

Various nitro azaheterocyclic compounds were subjected to C–H amination by vicarious nucleophilic substitution with 4H-1,2,4-triazol-4-amine (ATA). The aminated products were characterized by NMR, mass spectroscopy, and single-crystal X-ray diffraction analyses. The substrates examined gave moderate to excellent yields (30–88%) and showed good regioselectivities. This protocol offers the advantages of mild conditions, a short reaction time (2–4 hours), and an inexpensive, commercially available, and less-toxic amination reagent; moreover, no additional catalyst or reagent is needed. A possible reaction mechanism is discussed.
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Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

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Publication date: 1 February 2022

Source: Coordination Chemistry Reviews, Volume 452

Author(s): Priyanka Aggarwal, Debasish Sarkar, Kamlendra Awasthi, Prashanth W. Menezes

Electrocatalytic water splitting has been considered as a promising strategy for sustainable evolution of hydrogen energy and storage of intermittent electric energy. A self-supported electrode architecture is highly attractive. Here, we intend to offer a timely and comprehensive review of MOFs-derived self-supported carbon-based nanomaterials for electrocatalytic water splitting and a deep analysis and understanding of the relationship between the component manipulation and their properties is also showed. For more information, see the Review by Li et al. on page 15866.

Abstract

A copper(I)-catalyzed interrupted click-sulfenylation of O-/N-propargyl benzyl thiosulfonates with organic azides has been disclosed. The unified CuAAC-thiolation provides a wide range of triazole-fused eight-membered heterocycles in good to high (51–94%) yields under mild reaction conditions. Moreover, a three-component reaction is also achieved involving O-/N-propargyl benzyl thiosulfonates, benzyl bromide, and sodium azide to deliver fused-triazoles in 61–74% yields. From a synthetic point of view, the present protocol has been demonstrated at gram-scale reactions. A plausible mechanism is also proposed based on experimental results and control experiments.

Nature, Published online: 11 November 2021; doi:10.1038/d41586-021-03407-4

Publication date: 1 February 2022

Source: Coordination Chemistry Reviews, Volume 452

Author(s): Vasudha Hasija, Shilpa Patial, Pankaj Raizada, Aftab Aslam Parwaz Khan, Abdullah M. Asiri, Quyet Van Le, Van-Huy Nguyen, Pardeep Singh

A series of calix[4]pyrrole-based crosslinked polymer networks was synthesized via Sonogashira–Hagihara polycondensation. One system, C[4]P-BTP, was found to be highly effective for iodine capture from water with an uptake capacity of 3.24 g g⁻¹ and quick kinetics (k _obs=7.814 g g⁻¹ min⁻¹). Flow-through adsorption experiments revealed that C[4]P-BTP was able to remove 93.2 % of iodine from an aqueous phase with a flow rate of 1 mL min⁻¹.

Abstract

A series of calix[4]pyrrole-based crosslinked polymer networks designed for iodine capture is reported. These materials were prepared by Sonogashira coupling of α,α,α,α-tetra(4-alkynylphenyl)calix[4]pyrrole with bishalide building blocks with different electronic properties and molecular sizes. Despite their low Brunauer–Emmett–Teller surface areas, iodine vapor adsorption capacities of up to 3.38 g g⁻¹ were seen, a finding ascribed to the presence of a large number of effective sorption sites including macrocyclic π-rich cavities, aryl units, and alkyne groups within the material. One particular system, C[4]P-BTP, was found to be highly effective at iodine capture from water (uptake capacity of 3.24 g g⁻¹ from a concentrated aqueous KI/I₂ solution at ambient temperature). Fast capture kinetics (k_obs=7.814 g g⁻¹ min⁻¹) were seen. Flow-through adsorption experiments revealed that C[4]P-BTP is able to remove 93.2 % of iodine from an aqueous source phase at a flow rate of 1 mL min⁻¹.

Nature, Published online: 09 November 2021; doi:10.1038/d41586-021-03045-w

Nature, Published online: 05 November 2021; doi:10.1038/d41586-021-03026-z

Acceptorless dehydrogenative coupling reactions (ADC) and hydrogen transfer strategies (HT) have attracted much attention for the sustainable and atom-efficient formation of N-heterocycles. This Minireview emphasizes base metal catalyst systems which promote these cyclizations, and compares their activities with state-of-the-art noble metal catalysts.

Abstract

Acceptorless dehydrogenative coupling reactions (ADC) and hydrogen transfer strategies (HT) provide a powerful tool in the multicomponent formation of N-heterocycles. A broad variety of complex products can be obtained starting from simple, cheap and commercially available reagents. The protocols are highly atom-efficient, as water, dihydrogen, or in some cases hydrogen peroxide, are the only by-products. Moreover, neither further reducing or oxidizing agents, nor external hydrogen are in general required. Especially base metal-catalyzed strategies become ever more important. Therefore, in recent years, various different manganese, iron, cobalt, nickel and copper catalysts have been developed. This Minireview highlights the progress that has been made by using abundant metal complexes to promote multicomponent cyclizations for the formation of N-heterocycles and compares their performance with available noble metal catalyst systems.

Synthesis
DOI: 10.1055/a-1577-5864

This review article summarizes progress made on [1,2]-sigmatropic rearrangements using carbenes in the ylide formation step. While other rearrangements, such as the [2,3]-sigmatropic, Doyle–Kirmse, or Sommelet–Hauser rearrangements, have been studied in detail over the past decades, investigations on [1,2]-sigmatropic rearrangements are still limited. Based on the application of diazoalkanes as carbene precursors, research on diazoalkanes in ylide formation reactions started flourishing in the 1990s. This Short Review covers milestones from the advent of [1,2]-sigmatropic rearrangements using carbenes to generate ammonium, oxonium and other ylide species, and should serve as an overview to further promote research in this area.1 Introduction2 Ammonium Ylides3 Oxonium Ylides4 Sulfonium and Selenium Ylides5 Halonium Ylides6 Conclusion and Outlook
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Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

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