An interesting rhodium-catalyzed asymmetric aqueous Pauson-Khand-type reaction was developed. A chiral atropisomeric dipyridyldiphosphane ligand was found to be highly effective in this system. This operationally simple protocol allows both catalyst and reactants to be handled under air without precautions. Various enynes were transformed to the corresponding bicyclic cyclopentenones in good yield and enantiomeric excess (up to 95 % ee). A study of the electronic effects of the enyne substrates revealed a correlation between the electronic properties of the substrates and the ee value obtained in the product of the Pauson-Khand-type reaction. A linear free-energy relationship was observed from a Hammett study.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/chem.200401237 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Photosensitization enables Pauson-Khand-type reactions with nitrenes.
Science
February 2024
RWTH Aachen University, Institute of Organic Chemistry, Landoltweg 1, D-52074 Aachen, Germany.
The Pauson-Khand reaction has in the past 50 years become one of the most common cycloaddition reactions in chemistry. Coupling two unsaturated bonds with carbon monoxide, the transformation remains limited to CO as a C building block. Herein we report analogous cycloaddition reactions with nitrenes as an N unit.
View Article and Find Full Text PDFIntermolecular Pauson-Khand-Type Reaction of Vinyl Iodides with Alkynes and a CO Surrogate.
J Org Chem
April 2023
ETH Zürich, Vladimir-Prelog-Weg 3, HCI, 8093 Zürich, Switzerland.
A strategy for the palladium-catalyzed intermolecular synthesis of polysubstituted cyclopentenones is reported. The three-component reaction utilizes vinyl iodides and internal alkynes to form the carbon framework of the cyclopentenone with Cr(CO) serving as an easy to handle, solid CO surrogate, and a hydrosilane as a hydride source. We demonstrate the scope of the reaction which includes a wide range of functional groups.
View Article and Find Full Text PDFRhodium-Catalyzed Pauson-Khand-Type Cyclization of 1,5-Allene-Alkynes: A Chirality Transfer Strategy for Optically Active Bicyclic Ketones.
Chemistry
July 2019
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, P.R. China.
An efficient chirality transfer in the [RhCl(CO) ] -catalyzed [2+2+1] cyclization of optically active axially chiral 1,3-disubstituted allenynes with CO to access optically active bicyclopentenone compounds has been developed. The distal C=C bond of allenes reacted with the alknye unit and CO to afford [4.3.
View Article and Find Full Text PDFA Complementary Process to Pauson-Khand-Type Annulation Reactions for the Construction of Fully Substituted Cyclopentenones.
Org Lett
January 2019
Department of Chemistry , Dartmouth College, Burke Laboratory, Hanover , New Hampshire 03755 , United States.
A complementary process to the Pauson-Khand annulation is described that is well suited to forging densely substituted/oxygenated cyclopentenone products (including fully substituted variants). The reaction is thought to proceed through a sequence of metallacycle-mediated bond-forming events that engages an internal alkyne and a β-keto ester in an annulation process that forges two C-C bonds. A variant of this annulation process has also been established that delivers deoxygenated cyclopentenones that lack the allylic tertiary alcohol.
View Article and Find Full Text PDFIntegration of CO Reduction with Subsequent Carbonylation: Towards Extending Chemical Utilization of CO.
ChemSusChem
July 2018
State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China.
Currently, it still remains a challenge to amplify the spectrum of chemical fixation of CO , although enormous progress has been achieved in this field. In view of the widespread applications of CO in a myriad of industrial carbonylation processes, an alternative strategy is proposed in which CO reduction to CO is combined with carbonylation with CO generated ex situ, which affords efficiently pharmaceutically and agrochemically attractive molecules. As such, CO in this study was efficiently reduced by triphenysilane using CsF to CO in a sealed two-chamber reactor.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!