Results 141 to 150 of about 128,089 (280)

Nickel‐Catalyzed Enantioconvergent Arylation of Unactivated Cyclic Electrophiles: Asymmetric Synthesis of 3‐Substituted Pyrrolidines

Angewandte Chemie, EarlyView.
Metal‐catalyzed enantioconvergent substitutions of unactivated cyclic electrophiles by organometallic nucleophiles have not previously been reported. Herein, a chiral nickel catalyst is described that achieves this objective, coupling 3‐iodopyrrolidine derivatives with arylzinc nucleophiles.
Ting Hei Matthew Wong, Xiaoyu Tong, Gregory C. Fu   +2 more
wiley   +2 more sources

Magnetic decorated 5-sulfosalicylic acid grafted to chitosan: A solid acid organocatalyst for green synthesis of quinazoline derivatives

Carbohydrate Polymer Technologies and Applications
In this research, a new magnetically decorated multifunctional solid acid was designed and prepared conveniently by grafting of 5-sulfosalicylic acid (SSA) onto the chitosan (CS) backbone using toluene-2,4-diisocyanate (TDI) linker for the first time ...
Reyhaneh Peyvasteh Sourkouhi, Mohammad G. Dekamin, Ehsan Valiey, Mohammad Dohendou   +3 more
doaj   +1 more source

Diazo Transfer From Nitrous Oxide Employing Phosphorus Ylides

Angewandte Chemie, EarlyView.
A phosphorus ylide‐mediated strategy achieves the direct fixation of nitrous oxide (N2O) to access diazo compounds, which after intra‐ or intermolecular trapping, afford N2‐containing organic building blocks. This approach provides an alternative to hazardous diazo‐transfer reagents and establishes N2O fixation as a sustainable methodology.
Jhen‐Kuei Yu, Jan Niclas Ludwig, Patrick Wolf Antoni, David Tymann, Max Martin Hansmann   +4 more
wiley   +2 more sources

Azide‐to‐Diazo Transformation Facilitated by Michael Addition via Phosphazide Formation

Angewandte Chemie, EarlyView.
A new type of Michael addition based on azide‐to‐diazo conversion is disclosed. This unusual transformation proceeds via 1,4‐addition accompanied by N─N bond cleavage of phosphazide intermediates under practical conditions. The high versatility of the resulting Michael adducts enables the synthesis of a wide variety of organonitrogen compounds ...
Tomoki Mano, Takahiro Yasuda, Gaku Orimoto, Suguru Yoshida   +3 more
wiley   +2 more sources

Sulfur‐Directed Construction of Vinyl Cyclopropanes from 1,3‐Dienes

Angewandte Chemie, EarlyView.
Sulfur takes control. A pending thioether acts as a molecular compass, directing carbene addition to the 1,3‐diene scaffold with exceptional regio‑ and diastereocontrol to forge sulfur‐substituted vinyl cyclopropanes (S‐VCPs) — molecular architectures inaccessible via conventional cyclopropanation strategies.
Anna Keimer, Jonas Rettig, Tim‐Niclas Streit, Bob Barthel, Mélissa Calmels, Moritz Malischewski, Franz‐Lucas Haut   +6 more
wiley   +2 more sources

Hydrogen Isotope Exchange in Pyridine Catalyzed by an Iron(II) Imido Complex: Counterion‐Directed Regioselectivity

Angewandte Chemie, EarlyView.
Anionic high‐spin iron(II) imido complexes are catalysts for the hydrogen isotope exchange (HIE) reaction with pyridine as the substrate. The alkali metal counter‐cation plays critical roles in activating the substrate and facilitating deuteration. These complexes catalyze site‐selective α‐, α,β,γ‐, and β,γ‐deuteration of pyridine, where the counter ...
Bin Feng, Guorong Li, Yafei Gao, Nobuyuki Yamamoto, Maren Pink, Qian Peng, Jeremy M. Smith   +6 more
wiley   +2 more sources

From [NHC─H]• to Persistent σ‐Complex Radicals: Photoinduced Radical Chemistry of Imidazolium Salts

Angewandte Chemie, EarlyView.
Visible‐light excitation of electron donor–acceptor (EDA) complexes between imidazolium salts and triarylamines enables controlled single‐electron transfer (SET) and reveals a family of carbene‐centered σ‐complex radical cations. Cryogenic electron paramagnetic resonance (EPR) captures the elusive [NHC─H]• intermediate and its thermal evolution into ...
Filipp M. Kolomeychuk, Lars J. C. van der Zee, Simon Mathew, Bas de Bruin, J. Chris Slootweg   +4 more
wiley   +2 more sources

Bent N‐Heterocyclic Allenes From a Well‐Defined Titanium Vinylidene Complex

Angewandte Chemie, EarlyView.
The syntheses and the structures of N‐heterocyclic allenes are reported. Allenes bearing fluorenylidene capping groups show markedly bent C═C═C units, a carbene‐like reactivity, and they can act as potent C‐donor ligands for metal complexes. ABSTRACT Allenes typically display a linear geometry. A notable exception occurs in allenes bearing two electron‐
Bastiaan Kooij, Damien W. Chen, Rosario Scopelliti, Farzaneh Fadaei‐Tirani, Kay Severin   +4 more
wiley   +2 more sources

Bionanocomposite MIL-100(Fe)/Cellulose as a high-performance adsorbent for the adsorption of methylene blue

Scientific Reports
World production of dyes is estimated at more than 800,000 t·yr−1. The purpose of this research falls within the scope of the choice of an effective, local, and inexpensive adsorbent to remove dyes from wastewater.
Shahla Abbasi, Zahra Nezafat, Shahrzad Javanshir, Behzad Aghabarari   +3 more
doaj   +1 more source

Iterative Synthesis of Pentacene Derivatives with Continuous Boron–Oxygen Bonds

Angewandte Chemie, EarlyView.
An iterative synthetic strategy enables the controlled introduction of continuous multiple B–O bonds at the zigzag edge of acenes. A simple two‐step cycle—ipso iodination and Suzuki cross‐coupling/condensation—efficiently constructs BO‐acenes ranging from naphthalene to pentacene.
Seonghwa Jeong, Si‐In Kim, Jonghwan Lee, Hwon Kim, Jinuk Jang, Jiyeon Kim, Wonyoung Choe, Seung Kyu Min, Young S. Park   +8 more
wiley   +2 more sources