Search results for "coupling"
showing 10 items of 1862 documents
Influence of the Nature of Boron‐Doped Diamond Anodes on the Dehydrogenative Phenol‐Phenol Cross‐Coupling
2019
Anodic coupling of guaiacol derivatives on boron-doped diamond electrodes.
2011
The anodic treatment of guaiacol derivatives on boron-doped diamond electrodes (BDD) provides a direct access to nonsymmetrical biphenols, which would require a multistep sequence by conventional methods. Despite the destructive nature of BDD anodes they can be exploited for chemical synthesis.
Adiabatic-antiadiabatic crossover in a spin-Peierls chain
2004
We consider an XXZ spin-1/2 chain coupled to optical phonons with non-zero frequency $\omega_0$. In the adiabatic limit (small $\omega_0$), the chain is expected to spontaneously dimerize and open a spin gap, while the phonons become static. In the antiadiabatic limit (large $\omega_0$), phonons are expected to give rise to frustration, so that dimerization and formation of spin-gap are obtained only when the spin-phonon interaction is large enough. We study this crossover using bosonization technique. The effective action is solved both by the Self Consistent Harmonic Approximation (SCHA)and by Renormalization Group (RG) approach starting from a bosonized description. The SCHA allows to an…
Measuring High-Order Interactions in Rhythmic Processes Through Multivariate Spectral Information Decomposition
2021
Many complex systems in physics, biology and engineering are modeled as dynamical networks and described using multivariate time series analysis. Recent developments have shown that the emergent dynamics of a network system are significantly affected by interactions involving multiple network nodes which cannot be described using pairwise links. While these higher-order interactions can be probed using information-theoretic measures, a rigorous framework to describe them in the frequency domain is still lacking. This work presents an approach for the spectral decomposition of multivariate information measures, capable of identifying higher-order synergistic and redundant interactions betwee…
Electrochemical Synthesis of 2-Hydroxy-para-terphenyls by Dehydrogenative Anodic C–C Cross-Coupling Reaction
2019
The anodic C–C cross-coupling reaction provides fast access to a wide range of bi- and terarylic scaffolds by electrochemically mediated arylation reactions. Herein, a metal- and reagent-free electrosynthetic protocol for the synthesis of nonsymmetrical 2-hydroxy-para-teraryl derivatives is presented for the first time. It is scalable, easy to conduct, and allows the use of a broad variety of different functional groups.
Visible-Light Organophotoredox-Catalyzed Synthesis of Precursors for Horner-Type Olefinations
2018
Front Cover Picture: SBA‐15/POSS‐Imidazolium Hybrid as Catalytic Nanoreactor: the role of the Support in the Stabilization of Palladium Species for C…
2019
Synthese substituierter 1,4-Divinylbenzole durch doppelte Heck-Reaktion mit Ethen unter Druck
1999
Substituted 1,4-divinylbenzenes 3a–i were synthesized by twofold Heck coupling from the corresponding 1,4-dibromo) (electron withdrawing substituents) or 1,4-di-iododialkoxybenzenes 1a–i and ethene. Oligomerizations could be suppressed by increasing the pressure of ethene to 30 bar, simultaneously improving the yields of the title compounds.
MoVReagents in Organic Synthesis (Eur. J. Org. Chem. 11/2016)
2016
Cobalt−NHC Catalyzed C(sp2)−C(sp3) and C(sp2)−C(sp2) Kumada Cross‐Coupling of Aryl Tosylates with Alkyl and Aryl Grignard Reagents
2021
The first cobalt‐catalyzed cross‐coupling of aryl tosylates with alkyl and aryl Grignard reagents is reported. The catalytic system uses CoF3 and NHCs (NHC=N‐heterocyclic carbene) as ancillary ligands. The reaction proceeds via highly selective C−O bond functionalization, leading to the corresponding products in up to 98 % yield. The employment of alkyl Grignard reagents allows to achieve a rare C(sp2)−C(sp3) cross‐coupling of C−O electrophiles, circumventing isomerization and β‐hydride elimination problems. The use of aryl Grignards leads to the formation of biaryls. The C−O cross‐coupling sets the stage for a sequential cross‐coupling by exploiting the orthogonal selectivity of the cataly…