The α-umpolung of carbonyl compounds significantly expands the boundaries of traditional carbonyl chemistry. Despite various umpolung methods available today, reversing the inherent reactivity of carbonyls still remains a substantial challenge. In this article, we report the first use of sulfonium salts, of well-established hypervalent iodines, for the carbonyl umpolung event. The protocol enables the incorporation of a wide variety of heteroatom nucleophiles into the α-carbon of 2-oxazolines. The success of this investigation hinges on the following factors: (1) the use of sulfoxides, which are abundant, structurally diverse and tunable, and easily accessible, ensures the identification of a superior oxidant namely phenoxathiin sulfoxide for the umpolung reaction; (2) the "assembly/deprotonation" protocol previously developed for rearrangement reactions in our laboratory was successfully applied here for the construction of α-umpoled 2-oxazolines.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9093176 | PMC |
| http://dx.doi.org/10.1039/d2sc00476c | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Mechanistic 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 PDFNucleophilic Functionalization of Activated P in [CpFe(CO)-(η-P)][Al(OR)] with Alcohols R-OH.
Chemistry
January 2025
Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany.
The bonding situation in [Fp-P][Al(OR)] (1) (Fp = (CO)CpFe, R = C(CF)) gives rise to an Umpolung of the P fragment, which should make it accessible for nucleophiles. To investigate this projected reactivity, the complex was combined with a series of hydroxy-nucleophiles - that all do not react with free P - leading to a variety of P building blocks. With excess of R-OH (R = Me, Et, Ph), the thermodynamically more stable complex salts [Fp-P(H)(OR))][Al(OR)] (x=2,1,0) (2b-2d) are formed and show that the phosphonium type pathway is accessible.
View Article and Find Full Text PDFA Protocol for the Synthesis of Organophosphorus(V) Compounds with P-N and P-O Bonds by Umpolung Strategy Using Hydroxymethylphosphine Sulfides.
J Org Chem
January 2025
Department of Applied Chemistry, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790-8577, Japan.
Versatile P-N and P-O bond-forming reactions by an umpolung approach using air- and moisture-stable hydroxymethylphosphine sulfides were developed. Phosphine sulfides containing multiple hydroxymethyl groups could undergo sequential transformations combining P-N and P-O as well as P-C bond formations, providing a novel protocol for the synthesis of a variety of organophosphorus(V) compounds with P-N and P-O bonds.
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!