Chromium Carbene Complexes Research Articles

New lactone synthesis using a chromium carbene complex

A new lactone synthesis was developed using the Fischer chromium carbene complex. The lactone was formed from an alkyne bearing a hydroxyl or silyloxyl group in a tether, along with carbene carbon and carbon monoxide of the chromium carbene complex. Using this procedure, (+)-blastmycinone and (+)-antimycinone were synthesized from ( S)-ethyl lactate in short steps.

Intermolecular Carbene–Carbene Coupling of a Nucleophilic Vinylidene and an Electrophilic 1‐Methoxyethylidene Ligand

The first example of an intermolecular carbene–carbene coupling reaction between a Fischer and a Schrock carbene ligand is achieved by coupling of the vinylidene fragment in 1 with the methoxyethylidene ligand in 2. In the resulting red titanacyclic chromium carbene complex 3 the chromium is coordinated in such a way by the methoxy substituent that the bicyclic framework is virtually planar.

ChemInform Abstract: Novel Synthesis of Lactam from Alkyne Having Amide in a Tether Using Fischer Chromium Carbene Complex.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Characterization of chromium-carbene complexes by high-performance liquid chromatography-mass spectrometry with particle beam interface

High-performance liquid chromatography (HPLC) coupled with mass spectrometric (MS) detection was used to separate and characterize a series of chromium -aminocarbene and alkoxycarbene complexes of the Fischer type, some of which were synthesized as new compounds. Chromium-carbene complexes are known to have interesting photochemical properties. The separation of all the compounds examined was performed under normal-phase conditions and a particle beam LC-MS interface was used. The acquisition of positive-ion and negative-ion chemical ionization mass spectra of the eluates was performed. The use of the LC-PB-MS system demonstrated the potential role of this technique in the elucidation of the structure of polar organometallic compounds, such as the carbene complexes of chromium examined.

Reaction of Propargylsilanes with Chromium Carbene Complexes: Synthesis of Conjugated Diene Enol Ethers through a Tandem Alkyne Insertion-1,2-Silicon Shift Process.

Reaction of Propargylsilanes with Chromium Carbene Complexes: Synthesis of Conjugated Diene Enol Ethers through a Tandem Alkyne Insertion-1,2-Silicon Shift Process.

Photoreactions of γ,δ-Unsaturated Chromium Carbene Complexes

A number of functionalized γ,δ-unsaturated chromium carbene complexes were synthesized, and their photochemistry was studied. Photolysis of carbene complexes 5 and 17 induced intramolecular [2 + 2] cycloaddition to afford cyclobutanones 6 and 18, respectively. If the photoreactions were not run in thoroughly degassed solvents, small amounts of lactones 7 and 19 were obtained as well. Cyclobutanones 6 and 18 were stable once isolated, but underwent an acid-catalyzed Pinacol rearrangement/hydrolysis transformation in acidic solution to afford novel α-hydroxy-substituted bicyclo[3.1.0]hexanone compounds 20 and 21. Photolysis of cyclopropyl carbene complex 28 induced a vinylcyclopropyl rearrangement involving the photogenerated ketene moiety to provide α-alkoxy cyclopentenone 29.

Tricyclic pentacarbonyl carbene complexes of chromium: a novel synthetic pathway via diazo precursors and benzannulation

9-Diazo-9H-fluorene 2, 9-diazo-9H-xanthtene 3 and 5-diazo-5H-dibenzo[a,d]cycloheptene 4 react with pentacarbonyl(η2-cis-cyclooctene) chromium(0) 1 to give the novel tricyclic Fischer-type carbene complexes 5–7, which undergo benzannulation upon reaction with hex-1-yne.

Photochemical Reaction between Tertiary Allylic Amines and Chromium Carbene Complexes: Synthesis of Lactams via a Zwitterion Aza Cope Rearrangement.

Photolysis of chromium carbene complexes in the presence of tertiary allylic amines resulted in a zwitterionic aza Cope rearrangement to produce unsaturated lactams in fair yield.

Intermediates and Transition Structures of the Benzannulation of Heteroatom-Stabilized Chromium Carbene Complexes with Ethyne: A Density Functional Study

We present a density functional study of the benzannulation reaction of heteroatom-stabilized chromium pentacarbonyl carbene complexes with ethyne. According to our calculations, the benzannulation...

Novel synthesis of lactam from alkyne having amide in a tether using fischer chromium carbene complex

A novel lactam synthesis from alkyne having amide in a tether was developed. The reaction proceeds via a vinylketene complex generated from alkyne and Fischer chromium carbene complex, and the lactam ring was formed from carbon monoxide, alkyne carbon and nitrogen of tosylamide. The four-,five-, six-, and seven-membered lactams having a substituent at the α-position were obtained in good yields.

ChemInform Abstract: Asymmetric syn‐Selective Michael Addition of Enolates to Chiral 8‐ Phenylmenthyloxy Vinyl Chromium Carbene Complexes.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Chromium(0) Carbene Complexes Bearing Imino Tethers: Synthesis and Photochemical Reactivity.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A Novel Synthesis of Isoindoline and Isoquinoline Using Chromium Carbene Complex

Abstract The reaction of diyne 1 which has nitrogen in a tether with chromium carbene complex 2 afforded isoindoline 4 in good yield. In this reaction, the two carbene carbons (carbene carbon of chromium carbene complex and carbon monoxide) reacted with the two alkynes, respectively, to form an aromatic ring, that is, [2+2+1+1] cocyclization. Using this procedure, isoquinoline derivatives, 6a, 7a, and 9a, were synthesized.

Organic Syntheses via Transition Metal Complexes. 79. Aminomethylenation of (.beta.-NH-Aminoethenyl)carbene Complexes of Chromium and Tungsten

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrganic Syntheses via Transition Metal Complexes. 79. Aminomethylenation of (.beta.-NH-Aminoethenyl)carbene Complexes of Chromium and TungstenRudolf Aumann, Beate Jasper, and Roland FroehlichCite this: Organometallics 1995, 14, 7, 3167–3172Publication Date (Print):July 1, 1995Publication History Published online1 May 2002Published inissue 1 July 1995https://doi.org/10.1021/om00007a017RIGHTS & PERMISSIONSArticle Views53Altmetric-Citations7LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (749 KB) Get e-AlertsSupporting Info (2)»Supporting Information Supporting Information Get e-Alerts

Synthesis of Amino Acids and Peptides Using Chromium Carbene Complex Photochemistry

Synthesis of Amino Acids and Peptides Using Chromium Carbene Complex Photochemistry

Asymmetric syn‐Selective Michael Addition of Enolates to Chiral 8‐Phenylmenthyloxy Vinyl Chromium Carbene Complexes

AbstractMichael addition reactions of ketone and ester lithium enolates to optically active Fischer vinylcarbene complexes derived from (‐)‐8‐phenylmenthol take place with high syn selectivity and high levels of asymmetric induction. The initial Michael adducts can be further elaborated through diastereoselective addition of organometallic reagents to ketones and aldol reactions. Removal of the metal fragment and chiral auxiliary group leads to cyclic enol ethers with three or five contiguous stereogenic centers and of high enantiomeric purity.

New Synthesis of Functionalized Chromium Carbene Complexes Using Zinc Organometallics

New Synthesis of Functionalized Chromium Carbene Complexes Using Zinc Organometallics

ChemInform Abstract: Reaction of a Chromium Carbene Complex with 1‐Azadienes and the Synthesis of Trisubstituted Pyrroles.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Chromium(0) Carbene Complexes Bearing Imino Tethers: Synthesis and Photochemical Reactivity

Chromium(0) Carbene Complexes Bearing Imino Tethers: Synthesis and Photochemical Reactivity

ChemInform Abstract: Effect of Alkene Substituents on Molybdenum and Chromium Carbene Complex Mediated Cyclization Reactions.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.