Nitrogenated azaphilones are interesting natural products with a wide range of applications. The structure of these compounds is characterized by the presence of an isoquinolinone framework. Here, we describe a new multicomponent silver-catalysed reaction that allows the transformation of simple imines derived from ortho-alkynylbenzaldehydes into complex nitrogenated azaphilone-type molecules in a straightforward way. This atom-economical process is high yielding, technically very simple and proceeds through a series of cascade processes that imply cycloisomerisation and formal cross-coupling reactions. This conceptually new process formally involves the synchronised catalytic generation and selective coupling of a nucleophile (isoquinolinone) and an electrophile (isoquinolinium). Some interesting colour properties of the synthesized azaphilone-type molecules are discussed.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1002/chem.201700170 | DOI Listing |
Org Biomol Chem
June 2022
Key Laboratory of Medicinal Chemistry for Natural Resources, Ministry of Education and Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming, 650091, China.
An Ag-catalysed three-component reaction of alkynyl aryl ketones bearing an -methoxy group, element selenium, and arylboronic acid, providing a facile route to selenofunctionalized chromone products has been developed. This protocol features high efficiency and high regioselectivity, and the use of selenium powder as the selenium source. Mechanistic experiments indicated that the combined oxidative effect of (bis(trifluoroacetoxy)iodo)benzene and oxygen in the air pushes the catalytic redox cycle of the Ag catalyst and the phenylselenium trifluoroacetate formed is the key intermediate of the PIFA-mediated 6--electrophilic cyclization and selenofunctionalization reaction of alkynyl aryl ketones.
View Article and Find Full Text PDFOrg Biomol Chem
May 2022
Department of Chemistry, University of Cape Town, Rondebosch, Cape Town, 7700, South Africa.
An atom-efficient silver-catalysed double carboxylative strategy for the one-step synthesis of quinolin-2-ones an addition-cyclisation-elimination cascade sequence of oxamic acids to acrylic acids, mediated either thermally or photochemically, is reported. The reaction was applicable to the synthesis of a broad range of quinolin-2-ones and featured a double-disconnection approach that constructed the quinolin-2-one core the formal and direct addition of a C(sp)-H/C(sp)-H olefin moiety to a phenylformamide precursor.
View Article and Find Full Text PDFOrg Biomol Chem
August 2021
Departament de Química Orgànica, Facultat de Química, Universitat de València, Dr. Moliner 50, 46100 Burjassot, València, Spain.
Naphthols, hydroxyindoles and an activated phenol are reacted with differently substituted (E)-nitrobut-1-en-3-ynes using the commercially available Rawal's chiral squaramide. The corresponding β-nitroalkynes were obtained with good yields and excellent enantioselectivities. Moreover, dihydronaphthofurans can be accessed via silver catalysed cyclization in a tandem one-pot procedure, with high preservation of the optical purity.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
April 2021
Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149, Münster, Germany.
Hydroarylation is an effective strategy to rapidly increase the complexity of organic structures by transforming flat alkene moieties into three-dimensional frameworks. Many strategies have already been developed to achieve the hydroarylation of styrenes, however most of these reports examine the hydroarylation of unpolar, β-mono- or β-unsubstituted styrenes, while exploring mainly electron-rich benzene nucleophiles. Herein, we report a mild and general catalytic system for the selective hydroheteroarylation of multiply substituted styrenes and heteroaromatic styrenes.
View Article and Find Full Text PDFChem Commun (Camb)
June 2019
Department of Chemistry, Yale University, 275 Prospect St., New Haven, CT 06511, USA.
Silver-catalyzed nitrene insertion enables the formation of benzosultams in good yield and with regioselectivity complementary to other transition metal nitrene-transfer catalysts. Preferential formation of six-membered benzosultam rings predominates for alkyl-substituted benzenesulphonamide precursors. Ligand-controlled tunability is also achieved for benzenesulphonamides with γ-branched alkyl substituents.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!