Search results for "coupling"

Synthesis of Natural Products By Rhodium-Mediated Intramolecular C-H Insertion

1998

The strategic advantages of the Rh-mediated intramolecular C–H insertion, which has been used as the key step in several natural product syntheses, are described here. The most recent such synthesis is the elegant route to (+)-morphine shown below.

ChemInform Abstract: Light Induced C-C Coupling of 2-Chlorobenzazoles with Carbamates, Alcohols, and Ethers.

2016

A light induced, transition-metal-free C-C coupling reaction of 2-chlorobenzazoles with aliphatic carbamates, alcohols, and ethers is presented. Inexpensive reagents, namely sodium acetate, benzophenone, water, and acetonitrile, are employed in a simple reaction protocol using a cheap and widely available 25 W energy saving UV-A lamp at ambient temperature.

Phenanthroline Ligands with Divergent Pyridine Units

2009

2-Mono- and 2,9-di-substituted 1,10-phenanthrolines with 4-pyridine units attached either via 1,4-phenylene- or 4-ethynyl-phenyl spacers, have been synthesised. The strategy is based on the introduction of 4-trimethylsilylphenyl group(s) at the phenanthroline core with the subsequent ipso-substitution of TMS groups by bromine or iodine and successive Suzuki or Sonogashira reactions with 4-pyridineboronic acid or 4-ethynylpyridine, respectively.

ChemInform Abstract: Preparation and Nonlinear Optics of Monodisperse Oligo(1,4-phenyleneethynylene)s.

2010

Oligo(1,4-phenyleneethynylene)s 1a−e, with solubilizing propoxy side chains, were prepared by use of Hagihara−Sonogashira coupling reactions. The synthetic strategy was based on a building block system and on the use of trimethylsilyl and triisopropylsilyl protecting groups that could be cleaved selectively. The extension of the conjugation with an increasing number of repeat units provokes a bathochromic shift of the long wavelength absorption and a superlinear increase of the second hyperpolarizability |γ|. The corresponding third harmonic generation (THG) measurements were performed using polystyrene matrices and variable laser wavelengths. We conclude that the conjugation length is much…

ChemInform Abstract: Gold-Catalyzed Intramolecular Hydroamination of o-Alkynylbenzyl Carbamates: A Route to Chiral Fluorinated Isoindoline and Isoqui…

2013

Title compounds are prepared in enantiomerically pure form by the diastereoselective addition of fluorinated nucleophiles to N-(tert-butanesulfinyl)imines (I) followed by a sequence of Sonogashira cross-coupling/gold(I)-catalyzed cycloisomerization of the corresponding carbamate.

Iodine oxidative coupling of diene and triene-diolates of unsaturated carboxylic acids.

1991

Abstract Oxidative Coupling of the dianions of unsaturated carboxylic acids 1 , and 4 with iodine, which provides a convenient and facile preparation of γ,γ and e,e-dicarboxylic acids 2 and 5, apparently occurs through SET substitution of intermediate iodo-carboxylates.

ChemInform Abstract: Iodine Oxidative Coupling of Diene- and Triene-Diolates of Unsaturated Carboxylic Acids.

2010

Abstract Oxidative Coupling of the dianions of unsaturated carboxylic acids 1 , and 4 with iodine, which provides a convenient and facile preparation of γ,γ and e,e-dicarboxylic acids 2 and 5, apparently occurs through SET substitution of intermediate iodo-carboxylates.

Optimization Strategies for the Anodic Phenol‐Arene Cross‐Coupling Reaction

2021

Polycondensed nitrogen heterocycles. Part 22. Pyrrolo[3,4-d]-1,2,3-triazines: A new ring system as potential antineoplastic agent

1989

Diazotization of the 3-aminopyrrole-4-carboxamides 6a,b under different conditions directly led to the new ring system pyrrolo[3,4-d]-1,2,3-triazine in excellent yields through an intramolecular coupling reaction. In all the cases it was impossible to isolate the intermediate 3-diazopyrroles.

Temperature dependence of the static structure factor of ortho-terphenyl in the supercooled liquid regime close to the glass transition

1993

Abstract Studying the temperature dependence of the static structure factor of ortho-terphenyl from the liquid state down to the glass we find that the main peak of S ( Q ) is split into two maxima which behave quite differently. While the maximum at Q =1.4 A −1 is not much affected by the temperature variation the one at 1.9 A −1 is significantly enhanced. This effect is connected with a change of the short range order, i.e. of the intermolecular distances, but evolves continuously. Thus the dynamic anomalies that have been observed in this system around a characteristic temperature T c ≈290 K are not simply due to a discontinuous change in S ( Q ) but can be attributed to the existence of…