Nitrogen Heterocyclic Carbene Research Articles

Synthesis of enantiomerically pure N-(2,3-dihydroxypropyl)arylamides via oxidative esterification

A highly efficient synthesis of enantiomerically pure (S) and (R)-isomers of N-(2,3-dihydroxypropyl)arylamides has been developed with good overall yields in a two step process. The key step involves the ring opening of the chiral epoxide with a nitrogen heterocyclic carbene (NHC) and further rearrangement to chiral N-(2,3-dihydroxypropyl)arylamides in high yields and enantioselectivity. During the reaction, no erosion in chiral purity was observed.

NHC-Gold-Alkyne Complexes: Influence of the Carbene Backbone on the Ion Pair Structure

We have studied the ion pair structure of [NHC-Au(η2-3-hexyne)][BF4] (NHC = nitrogen-heterocyclic carbene) by solution NOE NMR spectroscopy and relativistic DFT calculation. The neutral complexes [...

ChemInform Abstract: Metal‐Free Arylation of Benzene and Pyridine Promoted by Amino‐Linked Nitrogen Heterocyclic Carbenes.

AbstractAn amino‐linked nitrogen heterocyclic carbene mediates the carbon—carbon coupling reaction through direct C—H functionalization of benzene (II) and pyridine (IV) with aryl iodides (I) in the absence of a metal catalyst.

Metal-free arylation of benzene and pyridine promoted by amino-linked nitrogen heterocyclic carbenes

An amino-linked nitrogen heterocyclic carbene (amino-NHC), 1-tBu, has been shown to mediate carbon-carbon coupling through the direct C-H functionalization of benzene and pyridine in the absence of a metal catalyst. Using EPR, the first spectroscopic evidence corroborating the single electron transfer mechanism for the metal-free carbon-carbon coupling manifold, as reported by others, is introduced.

Highly stereoselective synthesis of (1E)-2-methyl-1,3-dienes by palladium-catalyzed trans-selective cross-coupling of 1,1-dibromo-1-alkenes with alkenylzinc reagents.

Ligand control: The use of Pd complexes containing tBu3P or nitrogen-heterocyclic carbene (NHC) ligands almost completely prevents stereoisomerization, thereby permitting an efficient and selective methylation and higher alkylation of (Z)-2-bromo-1,3-dienes (see scheme, dba=trans,trans-dibenzylideneacetone).

Highly active nickel catalysts for the isomerization of unactivated vinyl cyclopropanes to cyclopentenes.

Inflatable rings: Low-valent Ni0–nitrogen-heterocyclic carbene catalysts were found to isomerize activated and unactivated vinyl cyclopropanes to their respective substituted cyclopentenes under mild conditions and in high yields (see scheme, cod=cycloocta-1,5-diene). Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2004/z53469_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.