The umpolung of β,γ-unsaturated diketones through N-heterocyclic carbene catalysis is described, which allows access to a variety of highly functionalized bicyclic cyclohexene-β-lactones and 1,3,4-triaryl benzenes. An unprecedented reaction pattern involving the catalytic formation of nucleophilic O-acylated homoenolate intermediate is proposed. A diverse set of transformations on the product further showed the synthetic potential of this protocol.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acs.orglett.7b03358 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Exploring Divergent Role of Amine in Chemodivergent Synthesis of 4-alkyl/aryl-3H-1,2-Dithiole-3-thione and Ketothioamide.
Chemistry
January 2025
Central University of Gujarat, School of Chemical Sciences, Sector 30, 382030, Gandhinagar, INDIA.
The selective synthesis of 4-alkyl/aryl-3H-1,2-dithiole-3-thione in THF and water-dependent switchable product ketothioamide is demonstrated. The presented method describes explicitly the synthesis of the extremely rare positional isomer 4-alkyl/aryl-3H-1,2-dithiole-3-thione, a unique structure distinct from another positional isomer, 5-alkyl/aryl-3H-1,2-dithiole-3-thione. The unique umpolung of the nitromethyl group is exploited for solvent selective nucleophilic sulfur and amine addition.
View Article and Find Full Text PDFPolarity reversal, or "umpolung", is a widely acknowledged strategy to allow organic functional groups amenable to react in alternative ways to the usual preference set by their electronic features. In this article, we demonstrate that cyclohexyne umpolung, realized through complexation to zirconocene, makes the small strained cycloalkyne amenable to C-F bond functionalisation. Such strong bond activation chemistry is unprecedented in "free" aryne and strained alkyne chemistry.
View Article and Find Full Text PDFMechanistic Pathways in Cyanide-Mediated Benzoin Condensation: A Comprehensive Electron Localisation Function (ELF) and Catastrophe Theory Analysis of the Umpolung Reaction.
Molecules
January 2025
Faculty of Chemistry, University of Wroclaw, 50-383 Wroclaw, Poland.
This research investigates the mechanism of the cyanide-type umpolung reaction in benzoin condensation using topological analysis of ELF and catastrophe theory. The study achieves a comprehensive understanding of the evolution of chemical bonds and non-bonding electron density in the reaction of benzaldehyde and cyanide ions. The results reveal that the reaction proceeds through five transition state structures, with the formation of Lapworth's cyanohydrin being the rate-determining step.
View Article and Find Full Text PDFCatalytic Enantioselective Synthesis of 1,4-(Hetero) Dicarbonyl Compounds through α-Carbonyl Umpolung.
J Am Chem Soc
January 2025
Institute of Organic Chemistry, University of Leipzig, 04103 Leipzig, Germany.
The enantioselective synthesis of 1,4-dicarbonyl compounds continues to pose a significant challenge in organic synthesis, and a catalytic process which generates two adjacent stereogenic centers with full stereochemical control is lacking until now. The 1,4-relationship of the functional groups requires an Umpolung strategy as one of the α-carbonyl positions has to be inverted into an electrophilic center to react with a normal enolate. We report herein the highly enantio- and diastereoselective addition of silyl ketene acetals toward electrophilic 1-azaallyl cations to furnish chiral 4-hydrazonoesters, which are masked 1,4-dicarbonyl compounds.
View Article and Find Full Text PDFLight-Dependent Amide or Thioamide Formation of Acylsilanes with Amines using Elemental Sulfur.
Chemistry
January 2025
School of Chemistry, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
Due to the diverse chemical and physical properties of functional groups, mild and controllable ligation methods are often required to construct complex drugs and functional materials. To make diverse sets of products with tunable physicochemical properties, it is also useful to employ complimentary ligation methods that adopt the same starting materials. Here, we disclose the efficient and modular synthesis of amides or thioamides through the chemical ligation of acylsilanes with amines, simply by turning a light on or off.
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!