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.

A theoretical study focusing on the ring expansion that occurs in the reaction of N-heterocyclic carbenes with silanes has been carried out. A detailed reaction pathway was determined which indicates that formation of C-H bonds is the crucial factor in the transformation.

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 quaternary α-hydroxyphosphonates in good to excellent yield.

The effect of substituents at the heteroatom on the electronic structures of different N-heterocyclic carbenes (1, 2 and 3), silylene (4) and germylene (5) are examined using Density Functional Theory. The kinetic and thermodynamic stabilities of these molecules are assessed by examining the HOMO-LUMO gap and hydrogenation energies, respectively. The extent of cyclic electron delocalization pre...

Functionalization of N-heterocyclic carbenes (NHCs) has an important influence on their stability, Lewis donor, and acceptor properties. In this study, we report on the selective functionalization of a four-membered N-heterocyclic bis-silylene (2,6-Ar2C6H3NSi:)2 (1) (Ar = 2,4,6-iPr3C6H2) with mono-oxygen sources N2O and Me3NO. Treatment of 1 with N2O results in the selective formation of mono-s...

An easy to operate method of catalytic hydroboration of unsaturated compounds has been developed with wide substrate scope. Reactions of various aldimines, ketimines, α,β-unsaturated carbonyl compounds, and alkynes were successfully executed with bis(pinacolato)diboron and N-heterocyclic carbenes in methanol without requiring a transition metal or inert atmosphere.

An electron-withdrawing group was introduced to the α-position of chalcones, and the resulting alkylidene diketones showed new reactivities with enals under the catalysis of N-heterocyclic carbenes (NHCs). Selective activation of enals affords enolate equivalents that undergo highly enantioselective intermolecular Diels-Alder reactions with the alkylidene diketones. No products that might have ...

Novel rhodium(I) complexes with N-heterocyclic carbenes bearing a 2,3,4,5-tetraphenylphenyl and its higher dendritic frameworks were synthesized and the complexes were used as catalysts in rhodium-catalyzed hydrosilylation of alpha,beta-unsaturated ketones to show high 1,4-adduct selectivity.

A novel electrochemical procedure for the preparation of metal complexes of N-heterocyclic carbenes using imidazolium salts or corresponding silver-NHC complexes as carbene sources and electrolytes, and metal plates as the sacrificial anodes is described. The procedure is simple and good yielding without the use of expensive or air-sensitive reagents.