Reactions Of Diazo Compounds Research Articles

Mechanistic study on gold(I)‐catalyzed crosscoupling of diazo compounds: A DFT study

AbstractThe reaction mechanisms of the gold(I)‐catalyzed cross‐coupling reaction of aryldiazoacetate R1 with vinyldiazoacetate R2 leading to N‐substituted pyrazoles have been theoretically investigated using density functional theory calculations. Two possible reaction mechanisms were examined and discussed. The preferred reaction mechanism (mechanism A) can be characterized by five steps: the formation of the gold carbenoid A2 via the attack of catalyst to R1 (step I), nucleophilic addition of another reactant R2 to generate intermediate A3 (step II), intramolecular cyclization of A3 to form intermediate A4 (step III), hydrogen migration to give intermediate A5 (step IV), and catalyst elimination affording the final product P1 (step V). Step IV is found to be the rate‐determining step with an overall free energy barrier of 28.3 kcal/mol. Our calculated results are in good agreement with the experimental observations. The present study may provide a useful guide for understanding these kinds of gold(I)‐catalyzed cross‐coupling reactions of diazo compounds.

Diazo Esters as Dienophiles in Intramolecular (4 + 2) Cycloadditions: Computational Explorations of Mechanism.

The first experimental examples of Diels-Alder (DA) reactions of diazo compounds as heterodienophiles with dienes have been studied with density functional theory (DFT) using the M06-2X functional. For comparison, the reactivities of diazo esters as dienophiles or 1,3-dipoles with 1,3-dienes in intermolecular model systems have been analyzed by the distortion/interaction model. The 1,3-dipolar cycloaddition is strongly favored for the intermolecular system. The intramolecular example is unique because the tether strongly favors the (4 + 2) cycloaddition.

A theoretical study on the reaction of diazocompounds with C70 fullerene

Using density functional theory calculations, we investigated the chemical functionalization of a C70 fullerene with diazocompounds which has been reported experimentally. The results indicate that the [5,6]-bond of the apex of C70 is more reactive than the equatorial bonds toward the cycloaddition of the diazocompounds. The energetic stability of phenyl C71 butyric acid methyl ester (PCBM)-type [5,6]-fulleroids (products) shows the same trend (1>2>3>4) to that observed experimentally. The reaction energy for different isomers of [5,6]-fulleroids is in the range of −23.3 to −37.7kcal/mol. Our frontier molecular orbital analysis explains the experimentally observed UV–vis spectrums and confirmed the formation of [5,6]-fulleroids rather than [6,6]-methanofullerenes. The electron–hole pair binding energy for C70 is calculated to be about 0.6 to 0.9eV. Theoretical 1H-nuclear magnetic resonance (NMR), in good agreement with the corresponding experimental data, was used to more investigate the structure of the most stable complex.

DFT Calculations on the Mechanism of Transition-Metal-Catalyzed Reaction of Diazo Compounds with Phenols: O-H Insertion versus C-H Insertion.

The reaction of diazo compounds with transition-metal carbenes is an efficient way to achieve the functionalization of chemical bonds in organic molecules, especially for the C-H and O-H bonds. However, the selective mechanisms of C-H and O-H bond insertions by various metal carbenes such as Rh and Cu complexes are not quite clear. In this work, we performed a comprehensively theoretical investigation of the phenol C-H and O-H bonds inserted by Rh and Cu carbenes by using DFT calculations. The calculated results reveal that the nucleophilic additions of phenols to the Rh and Cu carbenes in the C-H bond insertions are the rate-determining steps of whole reactions, which are higher than the barriers in the O-H insertions. In the process of intramolecular [1,3]-H transfer, the Rh and Cu ligands in their carbenes tend to dissociate into solution rather than the intramolecular migration due to their weak metal-carbon bonds. A deeply theoretical analysis of the electronic structures of Rh, Cu, and Au carbenes as well as their complexes elucidated their differences in the chemoselectivity of C-H and O-H insertion products, which agrees with the experimental observations well.

ChemInform Abstract: Divergent Roles of Urea and Phosphoric Acid Derived Catalysts in Reactions of Diazo Compounds.

Hydrogen-bond-donor catalysts enable a variety of formal insertion reactions of diazo compounds. The role of the catalyst in the reaction system may vary depending on several factors, including the nucleophilicity of the diazo compound and the acidity of the insertion partner. Ureas and phosphoric acid derivatives can offer complementary reactivity patterns when selected as catalysts for selected O–H and S–H insertion reactions of aryl- and diazo-substituted esters.

ChemInform Abstract: Reaction of Diazocompounds with C70: Unprecedented Synthesis and Characterization of Isomeric [5,6]‐Fulleroids.

AbstractThe synthesis of a variety of PCBM‐type [5,6]‐fulleroids and their further highly selective photoisomerization to the respective [6,6]‐methanofullerenes is presented.

Reaction of Diazo Compounds with Difluorocarbene: An Efficient Approach towards 1,1-Difluoroolefins.

A transition-metal-free difluoromethylenation of diazo compounds that proceeds under mild conditions has been developed and is based on the use of TMSCF2 Br as the difluoromethylene source and tetrabutylammonium bromide (TBAB) as the promoter. The chemoselective formal carbene dimerization reaction is achieved owing to the electronic properties and the relative stability of the difluorocarbene intermediate.

Reaction of Diazo Compounds with Difluorocarbene: An Efficient Approach towards 1,1‐Difluoroolefins

AbstractA transition‐metal‐free difluoromethylenation of diazo compounds that proceeds under mild conditions has been developed and is based on the use of TMSCF2Br as the difluoromethylene source and tetrabutylammonium bromide (TBAB) as the promoter. The chemoselective formal carbene dimerization reaction is achieved owing to the electronic properties and the relative stability of the difluorocarbene intermediate.

Cover Picture: Construction of Multifunctionalized Azopyrazoles by Silver- Catalyzed Cascade Reaction of Diazo Compounds (Adv. Synth. Catal. 12/2015)

Cover Picture: Construction of Multifunctionalized Azopyrazoles by Silver- Catalyzed Cascade Reaction of Diazo Compounds (Adv. Synth. Catal. 12/2015)

ChemInform Abstract: Palladium‐Catalyzed Cross‐Coupling Reaction of Diazo Compounds and Vinyl Boronic Acids: An Approach to 1,3‐Diene Compounds.

AbstractA novel approach to 1,3‐dienes having one double bond in a carbocyclic or oxacyclic ring by Pd‐catalyzed coupling of α‐diazoketones and lactones with vinyl boronic acids is presented.

ChemInform Abstract: Trifluoromethylthiolation of Diazo Compounds Through Copper Carbene Migratory Insertion.

A strategy to introduce the SCF3 group through the CuI-promoted reaction of diazo compounds with the nucleophilic AgSCF3 trifluoromethylthiolation reagent was developed. Various diazo compounds were smoothly converted under mild conditions to form the C(sp3)–SCF3 bond. Mechanistically, migratory insertion of SCF3-bearing Cu carbene intermediates is involved in this transformation.

Reaction of diazocompounds with C70: unprecedented synthesis and characterization of isomeric [5,6]-fulleroids.

The synthesis of a variety of PCBM-type [5,6]-fulleroids and their further highly selective photoisomerization to the respective [6,6]-methanofullerenes is presented. Interestingly, the chemical reactivity of [5,6]-fulleroids reveals the same trend (a > b > c > d) to that observed for pristine C70 (α > β > γ > δ).

Cross-Coupling Reactions of Diazo Compounds and Vinylboronic Acids

Cross-Coupling Reactions of Diazo Compounds and Vinylboronic Acids

Trifluoromethylthiolation of Diazo Compounds through Copper Carbene Migratory Insertion

AbstractA strategy to introduce the SCF3 group through the CuI‐promoted reaction of diazo compounds with the nucleophilic AgSCF3 trifluoromethylthiolation reagent was developed. Various diazo compounds were smoothly converted under mild conditions to form the C(sp3)–SCF3 bond. Mechanistically, migratory insertion of SCF3‐bearing Cu carbene intermediates is involved in this transformation.

ChemInform Abstract: Reaction of Diazo Compounds with Organoboron Compounds

AbstractReview: 58 refs.

ChemInform Abstract: Diversity‐Oriented Three‐Component Reactions of Diazo Compounds with Anilines and 4‐Oxo‐Enoates.

AbstractThis new multicomponent reaction allows the selective synthesis of pyrrolidines or the corresponding linear α‐amino ester derivatives by controlling the addition sequence of the substrates.

Reaction of Diazo Compounds with Organoboron Compounds

The transition-metal-free reactions of diazo compounds with organoboron compounds are reviewed. This type of reaction provides an alternative approach for the formation of C–C, C–B, and C–Si bonds. Moreover, by using tosylhydrazones as diazo compound precursors and boronic acids/esters as the boron substrates, this type of reaction becomes of practical use in organic synthesis. This short review covers the recent developments of this area with an introduction to the historical background. 1 Introduction 2 Reaction of Diazo Compounds with Organoboranes 3 Reactions of Diazo Compounds with Boronic Acids and Related Organoborons 4 Reaction of Diazo Compounds with Boronic Esters 5 Concluding Remarks

Diversity‐Oriented Three‐Component Reactions of Diazo Compounds with Anilines and 4‐Oxo‐Enoates

Zwei Wege stehen der Titelreaktion offen, je nachdem, in welcher Reihenfolge die Substrate zugegeben werden. Auf divergente Weise entstehen mehrfach funktionalisierte Produkte – Pyrrolidine oder lineare α-Aminoester-Derivate – in guten Ausbeuten und mit hohen Diastereoselektivitäten.

Diversity‐Oriented Three‐Component Reactions of Diazo Compounds with Anilines and 4‐Oxo‐Enoates

This new multicomponent reaction allows the selective synthesis of pyrrolidines or the corresponding linear α-amino ester derivatives by controlling the addition sequence of the substrates.

ChemInform Abstract: Trapping of Oxonium Ylides with Michael Acceptors: Highly Diastereoselective Three‐Component Reactions of Diazo Compounds with Alcohols and Benzylidene Meldrum′s Acids/4‐Oxo‐enoates.

AbstractIt is revealed that the title compounds are suitable Michael acceptors for interception of oxonium ylides generated from diazo compounds and alcohols via a 1,4‐addition mode.