Results 51 to 60 of about 14,653 (264)

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

NHCs Catalyzed Hydrophosphonylation of α-Ketoesters and α-Trifluoromethyl Ketones

The Scientific World Journal, 2013
N-Heterocyclic carbenes catalyzed hydrophosphonylation reaction of α-ketoesters and α-trifluoromethyl ketones was developed. Under the catalysis of 10 mol% IPr, α-ketoesters or α-trifluoromethyl ketones reacted with dialkyl phosphites to provide ...
Lin He, Zhi-Hua Cai, Ji-Xin Pian, Guang-Fen Du   +3 more
doaj   +1 more source

Flexible cycloalkyl-substituted N-heterocyclic carbenes

Dalton Transactions, 2010
The use of two metal systems cis-Pt(NHC)(2)Me(2) and cis-Ir(NHC)(CO)(2)Cl help to highlight the flexibility of a series of cycloalkyl-substituted N-heterocyclic carbene ligands (ICy, ICy(7), ICy(8), ICy(12)). Bond dissociation enthalpies of several N-heterocyclic carbenes (NHCs) in cis-Pt(NHC)(2)Me(2) are estimated.
Fortman, G. C.; Slawin, A. M. Z.; Nolan, S. P.   +3 more
openaire   +2 more sources

Ruthenium Olefin Metathesis Catalysts Bearing Carbohydrate-Based N-Heterocyclic Carbenes [PDF]

, 2010
Ru-based olefin metathesis catalysts containing carbohydrate-derived NHCs from glucose and galactose were synthesized and characterized by NMR spectroscopy. 2D-NMR spectroscopy revealed the presence of Ru−C (benzylidene) rotamers at room temperature, and
Grubbs, Robert H., Keitz, Benjamin K.
core   +2 more sources

Breaking boundaries in ammonia production at ambient conditions: Exploring pristine carbon allotropes as catalyst

Sustainable Chemistry for the Environment
The synthesis of ammonia from molecular nitrogen and hydrogen under ambient conditions remains one of the greatest challenges in chemical method development. Notable successes have been achieved using transition metal complexes.
Amrita Pathak, Saswati Garai, Arpit Dutta, Arijit Bag   +3 more
doaj   +1 more source

Vinylic Addition Polynorbornene in Catalysis [PDF]

, 2019
Vinylic addition polynorbornenes (VA-PNB) result from the insertion polymerization of norbornene or specific norbornene derivatives catalyzed by transition metal com- plexes. The VA-PNB skeleton is completely aliphatic and keeps the bicyclic structure of
Albéniz Jiménez, Ana Carmen, García Loma, Rodrigo   +1 more
core   +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

Generalization of the copper to late-transition-metal transmetallation to carbenes beyond N-heterocyclic carbenes [PDF]

, 2016
The authors gratefully acknowledge the Royal Society (University Research Fellowship to C.S.J.C.), the EPSRC (EP/J500549/1) and the DOE (DE-FG02-13ER16370) for financial support.Carbene transition-metal complexes have become a prevalent family of ...
Bertrand, Guy, Bidal, Yannick D., Cazin, Catherine S. J., Cordes, David B., Melaimi, Mohand, Santoro, Orlando, Slawin, Alexandra M. Z.   +6 more
core   +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

Charge-Transfer Adducts of Chalcogenourea Derivatives of N-Heterocyclic Carbenes with Iodine Monochloride

Molbank, 2022
In this communication, we investigate the reaction between seleno- and thiourea, derived from N-heterocyclic carbenes, with the interhalogen iodine monochloride.
Marina Saab, Fady Nahra, Kristof Van Hecke   +2 more
doaj   +1 more source