Suzuki-Miyaura coupling reactions are promoted by Pd complexes ligated with C₂-symmetric multi-dentate N-heterocyclic carbenes derived in situ from Pd(OAc)₂ and imidazolium salts. Good to excellent yields were obtained for aryl bromides as substrates. Turnover numbers of up to 10⁵ could be achieved with 5 × 10⁻⁴ mol% of Pd(OAc)₂/1 × 10⁻³ mol% NHC precatalyst in 24 h.

Linear two-coordinate copper complexes of cyclic (alkyl)(amino)carbenes (CAAC)CuX (X = halide) show photoluminescence with solid-state quantum yields of up to 96%; in contrast to previously reported Cu photoemitters the emission is independent of temperature over the range T = 4–300 K and occurs very efficiently by prompt rather than delayed fluorescence, with lifetimes in the subnanosecond range.

Chiral N-heterocyclic carbenes were found to be efficient catalysts for the formal [2+2] cycloaddition reaction of alkyl(aryl)ketenes and nitroso compounds to give the corresponding 1,2-oxazetidin-3-ones in moderate to good yields with high enantioselectivities. Reductive ring-opening of the oxazetidinones give the corresponding α-hydroxy acid derivatives in good yields.

N-Heterocyclic carbenes bearing poly(ethylene glycol) chains of different lengths have been designed and employed as ligands in palladium-catalyzed coupling reactions. The catalyst system having longer chains was found to be highly efficient for Suzuki-Miyaura coupling and borylation reactions employing aryl chlorides under mild reaction conditions.

Novel 1,3-dialkylperhydrobenzimidazolinium chloride salts were prepared as precursors of N-heterocyclic carbenes 3a-e by reacting N,N'-dialkylcyclohexandiamine, triethyl orthoformate and ammonium chloride. The salts were characterized spectroscopically and the complexes formed in situ from Pd(OAc)2 and 3 have been tested as catalysts in homogenous Heck and Suzuki reactions.

A series of C₂-symmetric chiral benzimidazolium salts, the precursor of N-heterocyclic carbene ligands, were designed and synthesized from 1,2-dibromobenzene. In situ prepared corresponding carbenes were tested in the asymmetric palladium-catalyzed intramolecular α-arylation of amides, affording chiral diarylmethanols with high yields and moderate enantioselectivities.

7-Aryl-1,3,5-cycloheptatrienes react intermolecularly with methylenecyclopropanes in a triple gold(I)-catalyzed reaction to form cyclopentenes. The same formal (4+1) cycloaddition occurs with cyclobutenes. Other precursors of gold(I) carbenes can also be used as the C1 component of the cycloaddition.

Unexpected and unprecedented directed remote lateral lithiation at one CH(CH3)2 of the 3-(2,6-di-isopropylphenyl) wingtip took place upon the reaction of functionalised N-heterocyclic carbene-type molecules with excess of LiCH2SiMe3, leading to dilithiated dianionic 4-amido-N-heterocyclic carbenes. DFT calculations show that the nature of the isolated species are under thermodynamic control.

We report experimental and computational evidence that cationic N-heterocyclic carbene gold complexes with electron-rich cyclopropanes rearrange to produce Fischer gold carbene complexes in the gas phase, in analogy to long-known condensed-phase rearrangements of protonated cyclopropanes. Our results help to generalize the relationship between Lewis-acidic metal complexes of cyclopropanes, meta...

The organocatalytic behavior of N-heterocyclic carbenes in the aerobic oxidation of aromatic aldehydes to esters with boronic acids has been explored. This transition metal-free protocol allows access to a wide variety of aromatic esters in good to excellent yields under mild reaction conditions.