Diazocarbonyl Compounds Research Articles

A copper(I)-complexed magnetic nanoparticle catalyst for enaminone synthesis

The synthesis of a copper(I)-complexed magnetic nanoparticle catalyst is described. The catalyst was characterized using Fourier transform infrared spectroscopy (FT–IR), energy-dispersive X-ray spectroscopy (XPS), atomic absrobtion spectroscopy (AA), thermogravimetric analysis (TGA), vibrating sample magnetometery (VSM), X-ray photoelectron spectroscopy (XPS), scanning electron miscroscopy (SEM) and transmission electron microscopy (TEM). The catalyst coupled thioamides and diazocarbonyl compounds to produce diverse enaminones. The catalyst reduced the reaction times and temperature and provided enaminones in high yields and selectivity. Moreover, the catalyst can be separated by a magnet and recycled.

Total Synthesis of the Cyclic Dodecapeptides Wewakazole and Wewakazole B.

The cyclic dodecapeptides wewakazole and wewakazole B have been synthesized by a divergent strategy via a common tris-proline containing oxazole octapeptide and two separate bis-oxazole containing tetrapeptide units, followed by peptide coupling and macrocyclization. The three oxazole amino acid fragments are readily accessible by rhodium(II)-catalyzed amide N-H insertion of diazocarbonyl compounds, or by the cycloaddition of rhodium carbenoids with nitriles.

Negative ion Wolff rearrangement of some diazoketones: A theoretical mechanistic study

The mechanism of the Wolff rearrangement of some deprotonated diazocarbonyl compounds has been studied using density functional calculations, for both the gas and aqueous phases. The anionic rearrangement of the deprotonated analogues proceeds in a similar manner to the neutral counterparts. In the gas phase, the syn and anti conformers form the deprotonated ketene product concertedly. In certain analogues, the reaction of the anti conformer occurs non-concertedly, involving a deprotonated carbene-like intermediate. The migratory aptitude is similar to that in the neutral rearrangement, except that methoxy and amino substituents exchange positions.

Total Synthesis of the Post-translationally Modified Polyazole Peptide Antibiotic Goadsporin.

The structurally unique polyazole antibiotic goadsporin contains six heteroaromatic oxazole and thiazole rings integrated into a linear array of amino acids that also contains two dehydroalanine residues. An efficient total synthesis of goadsporin is reported in which the key steps are the use of rhodium(II)-catalyzed reactions of diazocarbonyl compounds to generate the four oxazole rings, which demonstrates the power of rhodium carbene chemistry in organic chemical synthesis.

Advances in the TBAF-induced aldol-type addition of α-trialkylsilyl-α-diazoacetones: TIPS versus TES

α-Triisopropylsilyl-α-diazoacetone (TIPS-diazoacetone) underwent high-yielding “diazo-side” Mukaiyama aldol-type addition with a range of aryl and alkyl aldehydes when subjected to stoichiometric amount of tetrabutylammonium fluoride at −16 °C, in Et 2 O. Robustness of the TIPS group makes TIPS-diazoacetone a stable surrogate for α-triethylsilyl-α-diazoacetone, on which generation of the corresponding carbanion can still be efficiently achieved under nucleophilic, weakly basic and practical conditions. These results highlight the synthetic potential that can be expected from TIPS-diazoacetone, promising building block for the convergent elaboration of highly functionalised versatile diazocarbonyl compounds.

Copper-catalyzed chemoselective cross-coupling reaction of thioamides and α-diazocarbonyl compounds: Synthesis of enaminones

The development of operationally simple and cost-effective methods for CC bond formation reactions are highly important in pharmaceutical, agrochemical and material research. In this article we describe the first copper-catalyzed cross-coupling reaction of thioamides with acceptor/acceptor-substituted and acceptor-only substituted α-diazocarbonyl compounds to yield enaminones. The reaction shows broad substrate scope in terms of thioamides and diazocarbonyl compounds. Primary, secondary and tertiary thioamides all give enanminones when reacted with α-diazodiesters, α-diazoketoesters, α-diazodiketones, α-diazoketoamides, α-diazoesteramides, α-diazoketosulfones and α-diazomonoketones.

Chemical Synthesis of the ODM-201's Diastereomers through an Efficient Intramolecular 1,3-Dipolar Cycloaddition.

An efficient synthesis of ODM-201's diastereomers has been developed from (R)-methyl 3-hydroxybutanoate or (S)-methyl 3-hydroxybutanoate, respectively, with high overall yield and excellent diastereomeric purity. The key step in this synthesis is the preparation of the key intermediate (R)-5-(1-((tert-butyldimethylsilyl)oxy)ethyl)-1H-pyrazole-3-carboxylic acid or (S)-5-(1-((tert-butyldimethylsilyl)oxy)ethyl)-1H-pyrazole-3-carboxylic acid through intramolecular 1,3-dipolar cycloaddition of the vinyl diazo carbonyl compounds.

Cyclopolymerization of Bis(diazocarbonyl) Compounds Leading to Well-Defined Polymers Essentially Consisting of Cyclic Constitutional Units

Cyclopolymerization of bis(diazocarbonyl) compounds is described for the first time. By choosing appropriate reaction conditions and monomer structures, the cyclopolymerization of bis(diazoacetate)s efficiently proceeded to give carbon–carbon main chain cyclopolymers with well-defined structures, as confirmed by MALDI-TOF-MS analyses. The products are a new kind of cyclopolymer with respect to polymer structure: there exists no free methylene in the sp3-carbon-based polymer backbone in contrast to conventional cyclopolymers prepared from divinyl compounds, which inevitably have free methylenes in and between cyclic units in their polymer backbones. The resulting cyclopolymers with closely aligned cyclic units along the polymer backbone showed a much higher glass transition temperature compared to the corresponding polymers without cyclized repeating units.

ChemInform Abstract: Copper‐Catalyzed Coupling of 2‐Siloxy‐1‐alkenes and Diazocarbonyl Compounds: Approach to Multisubstituted Furans, Pyrroles, and Thiophenes.

We report herein copper(II)-catalyzed cyclization reactions of silyl enol ethers derived from methyl ketones with α-diazo-β-ketoesters or α-diazoketones to afford 2-siloxy-2,3-dihydrofuran derivatives or 2,3,5-trisubstituted furans, respectively, under mild conditions. The former cyclization products serve as versatile 1,4-diketone surrogates, allowing facile preparation of 2,3,5-trisubstituted furans, pyrroles, and thiophenes.

ChemInform Abstract: Rhodium‐Catalyzed Geminal Oxyfluorination and Oxytrifluoro‐Methylation of Diazocarbonyl Compounds.

AbstractStable and easily accessible benziodoxole reagents are used as fluorine source in reactions of aromatic and aliphatic diazocarbonyl compounds with a variety of alcohols, phenol, and carboxylic acids.

ChemInform Abstract: Unusual Reactions of Diazocarbonyl Compounds with α,β‐Unsaturated δ‐Amino Esters: Rh(II)‐Catalyzed Wolff Rearrangement and Oxidative Cleavage of N—H‐Insertion Products.

Rh(II)-сatalyzed reactions of aroyldiazomethanes, diazoketoesters and diazodiketones with α,β-unsaturated δ-aminoesters, in contrast to reactions of diazomalonates and other diazoesters, give rise to the Wolff rearrangement and/or oxidative cleavage of the initially formed N-H-insertion products. These oxidation processes are mediated by Rh(II) catalysts possessing perfluorinated ligands. The formation of pyrrolidine structures, characteristic for catalytic reactions of diazoesters, was not observed in these processes at all.

Synergistic Diazo-OH Insertion/Conia-Ene Cascade Catalysis for the Stereoselective Synthesis of γ-Butyrolactones and Tetrahydrofurans.

A novel and highly efficient diazo-OH insertion/Conia-ene cascade reaction of readily available homopropargylic acids and alcohols with diazo carbonyl compounds is described. The cascade reaction involves a synergistic Rh/Ag/Au catalyst cocktail and proceeds instantly with a variety of substituted diazo compounds and acids/alcohols to provide functionalized γ-butyrolactones and tetrahydrofurans with complete regio- and stereoselectivity. The unprecedented rate-enhancement, complete stereoselectivity, and the enabling of new Conia-ene cyclizations suggest a concerted [4+1]-cycloaddition reaction pathway under synergistic (Rh/Ag/Au)-catalysis conditions.

ChemInform Abstract: Palladium‐Catalyzed Intramolecular Carbene Insertion into C(sp3)—H Bonds.

AbstractA regioselective Pd‐catalyzed cyclization of α‐diazoesters to N‐arylpyrrolidines is developed.

Theoretical study of the mechanism of the Wolff rearrangement of some diazocarbonyl compounds

The Wolff rearrangement is a 1,2-rearrangement reaction of α-diazocarbonyl compounds, leading to ketene formation and the extrusion of nitrogen. The reaction may undergo a concerted mechanism or involve a carbene as an intermediate. There is also the possibility of its rearrangement to oxirene. In this work, we have performed density functional calculations to elucidate the mechanism of the thermal Wolff reaction for both the gas and aqueous phases. The concerted mechanism appears to be slightly favored over the stepwise mechanism for alkyl and aryl substitution of the aldehydic hydrogen. Various diazocarbonyl systems have been investigated in order to explore the influence of the migrating group on the activation barrier and course of reaction. The stepwise rearrangement is preferred in case of methoxy and amino substitution. The intermediate in the stepwise rearrangement is found to have an interesting structure, neither completely a carbene nor an oxirene.

Unusual reactions of diazocarbonyl compounds with α,β-unsaturated δ-amino esters: Rh(II)-catalyzed Wolff rearrangement and oxidative cleavage of N-H-insertion products.

Rh(II)-сatalyzed reactions of aroyldiazomethanes, diazoketoesters and diazodiketones with α,β-unsaturated δ-aminoesters, in contrast to reactions of diazomalonates and other diazoesters, give rise to the Wolff rearrangement and/or oxidative cleavage of the initially formed N–H-insertion products. These oxidation processes are mediated by Rh(II) catalysts possessing perfluorinated ligands. The formation of pyrrolidine structures, characteristic for catalytic reactions of diazoesters, was not observed in these processes at all.

Redox‐Neutral C1 Functionalization of Unprotected Tetrahydroisoquinolines with Diazo Carbonyl Compounds

AbstractA silver or acid‐mediated three‐component reaction of tetrahydroisoquinolines, benzaldehydes, and diazo compounds has been developed. The reaction provides a novel route to β‐amino‐α‐diazo compounds through redox‐neutral C1 functionalization of unprotected THIQs with diazo carbonyl motifs with high regioselectivity.

ChemInform Abstract: Dirhodium(II)‐Catalyzed Annulation of Enoldiazoacetamides with α‐Diazoketones: An Efficient and Highly Selective Approach to Fused and Bridged Ring Systems.

AbstractThe addition of a mixture of two structurally different diazocarbonyl compounds to a dirhodium catalyst produces the donor‐acceptor cyclopropane‐fused benzoxa[3.2.1]octane scaffolds (III) with excellent chemo‐, regio‐ and diastereoselectivity.

ChemInform Abstract: Amination of Diazocarbonyl Compounds: N—H Insertion under Metal‐Free Conditions.

Transition-metal-free intermolecular N–H insertion of α-diazocarbonyl compounds is reported. Among the series of nitrogen sources examined, dibenzenesulfonimide was found to be the choice in terms of the yields and the reaction time. Primary mechanistic experiments suggest that a pathway involving a sequence of protonation and nucleophilic substitution was preferred.

Copper-Catalyzed Coupling of 2-Siloxy-1-alkenes and Diazocarbonyl Compounds: Approach to Multisubstituted Furans, Pyrroles, and Thiophenes.

We report herein copper(II)-catalyzed cyclization reactions of silyl enol ethers derived from methyl ketones with α-diazo-β-ketoesters or α-diazoketones to afford 2-siloxy-2,3-dihydrofuran derivatives or 2,3,5-trisubstituted furans, respectively, under mild conditions. The former cyclization products serve as versatile 1,4-diketone surrogates, allowing facile preparation of 2,3,5-trisubstituted furans, pyrroles, and thiophenes.

ChemInform Abstract: Aminofluorination: Transition‐Metal‐Free N—F Bond Insertion into Diazocarbonyl Compounds.

AbstractUsing NFSI (II) as F and N source, geminal aminofluorination of aryl diazoesters (I) is achieved.