Reactivity umpolung allows us to consider nontraditional bond disconnections. We report herein that treatment of an alpha-haloaldehyde with a nucleophile in the presence of catalytic amounts of nucleophilic carbenes results in an internal redox reaction giving rise to a dehalogenated acylating agent as an intermediate by a new reaction manifold. A brief illustration of the scope of this reactio...

The dicarbene platinum complexes of the type [Pt(L)2]Br2 [5]Br2 – [8]Br2 (L = N-alkyl-N′picolylbenzimidazolin-2-ylidene) have been prepared by two different methods. The in situ deprotonation of picoline-functionalized benzimidazolium salts 1 – 4 with platinum acetylacetonate gave the platinum complexes [5]Br2 – [8]Br2 in good yields. Complex [8]Br2 has also been obtained by a ligand transfer r...

A novel DNA-based hybrid catalyst comprised of salmon testes DNA and an iron(III) complex of a cationic meso-tetrakis(N-alkylpyridyl)porphyrin was developed. When the N-methyl substituents were placed at the ortho position with respect to the porphyrin ring, high reactivity in catalytic carbene-transfer reactions was observed under mild conditions, as demonstrated in the catalytic enantioselect...

The reactivities of monoand dihalocarbene anions (CHCl•−, CHBr•−, CF2•−, CCl2•−, and CBrCl•−) were studied using a tandem flowing afterglow-selected ion flow tube instrument. Reaction rate constants and product branching ratios are reported for the reactions of these carbene anions with six neutral reagents (CS2, COS, CO2, O2, CO, and N2O). These anionswere found to demonstrate diverse chemistr...

Enantioselective α-alkylation of carbonyl is considered as one of the most important processes for asymmetric synthesis. Common alkylation agents, that is, alkyl halides, are notorious substrates for both Lewis acids and organocatalysts. Recently, olefins emerged as a benign alkylating species via photo/radical mechanisms. However, examples of enantioselective alkylation of aldehydes/ketones ar...

In this paper are reported the results of a comprehensive mechanistic study of nucleophilic attack by amines on coordinated isocyanides in square—planar Pd(II) complexes, leading to amino—carbene complexes. The reactivity pattern that has emerged displays several facets: (i) whatever the details, in this stepwise mechanism the most prominent step always involves direct attack of the amine nitro...

The trapping of the elusive vinylogous position a vinyl carbene with an aliphatic Csp3-H bond has been achieved for first time during silver-catalyzed carbene/alkyne metathesis (CAM) process. A Tpx-containing silver complex promotes generation donor-acceptor which triggers CAM, generating subsequent donor-donor species, then undergoes selective C(sp3)-H insertion, leading to synthesis new famil...

Rate and equilibrium constants for the reaction between N-aryl triazolium N-heterocyclic carbene (NHC) precatalysts and substituted benzaldehyde derivatives to form 3-(hydroxybenzyl)azolium adducts under both catalytic and stoichiometric conditions have been measured. Kinetic analysis and reaction profile fitting of both the forward and reverse reactions, plus onwards reaction to the Breslow in...

The facile syntheses of ring-expanded N-heterocyclic carbene (RE-NHC) copper(I) halide complexes are reported. method makes use a weak inorganic base in green solvent. reaction times can be greatly reduced by this weak-base route under microwave irradiation. easy access to these permits an evaluation the catalytic activity and profiling [Cu(RE-NHC)X] Huisgen 1,3-cycloaddition reaction.

Suzuki-Miyaura reaction of aryl and vinyl halides or triflates with organoboron reagents has developed into one of the most important C-C bond-forming reactions.1,2 The mild and simple reaction conditions, the availability of various boronic acids that are normally nontoxic and stable, and easy workup and separation of the products are some of the factors that are responsible for the increasing...