A Brønsted acid-catalyzed pinacol-type rearrangement pathway is reported here to synthesize various substituted α-(3-indolyl) ketones by employing unprotected indoles and α-hydroxy aldehydes as coupling partners. Utilization of economic and readily available Brønsted acid catalyst and use of simple starting precursors exemplify the economic viability of this method. Under this developed protocol, selective migration of aryl over alkyl or a second aryl group is observed depending upon the migratory aptitude of the substituents. Applicability of this method was further demonstrated by synthesizing highly substituted carbazoles through a simple extension of this method to one-pot cascade annulation strategy.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acs.joc.9b02474 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Intramolecular Inhibition by Imidazole in Acid-Catalyzed Hydrolysis of Protected Carbohydrates.
Chemistry
December 2024
Eotvos Lorand University, Organic Chemistry, Pazmany Peter Setany 1/A, 1117, Budapest, HUNGARY.
The present study reveals an unexpected anomaly observed in the acid-catalyzed hydrolysis of the 5,6-O-isopropylidene group in 3-O-protected D-gluco- and D-allofuranose derivatives. Although the removal of the 5,6-O-isopropylidene protecting group is typically rapid and quantitative under acidic conditions, an unexpected inhibition of this reaction is observed for the two C3-epimers, 3-O-imidazole sulfonyl moiety. X-ray data show a two-faced imidazole ring orientation in the crystal, while solution state NOE data reveal a critical interaction type between the isopropylidene and the imidazole rings.
View Article and Find Full Text PDFChiral Phosphoric Acid-Catalyzed Enantioselective Synthesis of 2,2-Disubstituted 2,3-Dihydro-4-quinolones from Isatins and 2'-Aminoacetophenones.
Org Lett
December 2024
Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan.
Herein, we present the enantioselective synthesis of 2,3-dihydro-4-quinolones bearing chiral tetrasubstituted carbons from isatins and 2'-aminoacetophenones. The transformation is mediated by a chiral phosphoric acid catalyst and proceeds via an generated ketimine and subsequent enantioselective intramolecular cyclization. The methodology features a broad scope and functional group tolerance with yields and enantioselectivities of up to 99% and 98% ee.
View Article and Find Full Text PDFAcid-Catalyzed Redox Isomerizations of 6,8-dioxabicyclo[3.2.1]octan-4-ols Provide Mechanistic Insights for Levoglucosenone Formation.
ChemSusChem
December 2024
University of New England, School of Science and Technology, 1 Elm Avenue, 2351, Armidale, AUSTRALIA.
Levoglucosenone is an important platform chemical and the principal product of acid-catalyzed cellulose pyrolysis, formed through several intermediates including levoglucosan. An acid-catalyzed redox isomerization of substituted 6,8-dioxabicyclo[3.2.
View Article and Find Full Text PDFDiverse Synthesis of Arene-Fused [n.1.1]-Bridged Molecules via Catalytic Cycloaddition and Rearrangement Reactions.
Angew Chem Int Ed Engl
December 2024
Xi'an Jiaotong University, Frontier Institute of Science and Technology, 99 Yanxiang road, Yanta district, 710054, Xi'an, CHINA.
Although great advancement has been made in synthesis of 3D bridged bicyclic[n.1.1]-bioisosteres, facile construction of 2D/3D merged molecules incorporating bridged rings, as novel chemical space in drug discovery, remains a significant challenge.
View Article and Find Full Text PDFSynthesis, Reactivity and Aromatic Characteristics of Porphyrinoids Derived from -Alkylcarbaporphyrin-2-Carbaldehydes: Isolation of Nickel(II) and Palladium(II) Complexes, Weakly Diatropic 21-Oxycarbaporphyrins and Strongly Aromatic Trioxycarbaporphyrins.
J Org Chem
December 2024
Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, United States.
Acid catalyzed condensation of -alkyltripyrranes with trialdehydes derived from 1,3-cyclopentadiene or methyl-1,3-cyclopentadiene, followed by oxidation with aqueous ferric chloride solutions, gave 23-alkyl-21-carbaporphyrin-2-carbaldehydes in 22-27% yield together with weakly aromatic oxycarbaporphyrins. The carbaporphyrins reacted with palladium(II) acetate or nickel(II) acetate to give organometallic complexes but in both cases alkyl group migration took place to generate 21-alkyl derivatives. Although this type of reactivity had been observed previously for palladium complexes, this is the first time the phenomenon has been seen in nickel(II) carbaporphyrins.
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!