Described herein is a convenient and highly selective synthesis of alkynylated isoquinolines and biisoquinolines from various aryl ketone O-pivaloyloxime derivatives and 1,3-diynes via rhodium-catalyzed C-H bond activation. In this transformations, alkynylated isoquinolines, 3,4'- and 3,3'-biisoquinolines could be obtained respectively through changing the reaction conditions. Mechanistic investigation revealed that the C-H activation of aryl ketone O-pivaloyloxime was the key step to this reaction.
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http://dx.doi.org/10.1021/acs.joc.7b01867 | DOI Listing |
J Org Chem
January 2025
Department of Chemistry, Indian Institute of Technology Indore, Indore 453552, Madhya Pradesh, India.
Herein, we report the -generated transient bromoiodane-mediated brominative annulation of 2-alkynyl arylimidate for the synthesis of 4-bromoisoquinolines at room temperature. Using a simple hypervalent iodine reagent PIDA as a mild oxidant and potassium bromide as the halogen source, a broad range of valuable 4-bromoisoquinolines can be synthesized in excellent yields. The reaction features readily available chemicals, mild metal-free conditions, and high functional group tolerance, providing an efficient alternative for the construction of halogenated isoquinolines.
View Article and Find Full Text PDFJ Org Chem
August 2024
Centro de Ciências Químicas, Farmacêuticas e de Alimentos (CCQFA), Universidade Federal de Pelotas (UFPel), P.O. Box 354, Pelotas, 96010-900 Rio Grande do Sul, Brazil.
Herein, we describe the use of benzeneseleninic acid derivatives (BSA) as a bench-stable and easy to handle selenium reagent to access 4-(selanyl)isoquinoline--oxides through the selenocyclization of -alkynyl benzaldehyde oximes. The reaction is conducted in refluxing methanol, allowing the thermal generation of electrophilic selenium species in situ. By this new protocol, a library of 19 selenium-decorated -oxide isoquinolines was accessed in up to 96% yield with an outstanding substrate tolerance and the feasibility to scale it up 10 times (from 0.
View Article and Find Full Text PDFChem Commun (Camb)
June 2024
Chang-Kung Chuang Institute, East China Normal University, 3663 N. Zhongshan Road, Shanghai 200062, China.
An efficient Rh(III)-catalyzed enantioselective C-H alkynylation of isoquinolines is disclosed. The C-H alkynylation of 1-aryl isoquinolines with hypervalent iodine-alkyne reagents proceeded in DMA at room temperature in the presence of 2.5 mol% chiral SCpRh(III) complex along with 20 mol% AgSbF, providing axially chiral alkynylated 1-aryl isoquinolines in excellent yields (up to 93%) and enantioselectivity (up to 95% ee).
View Article and Find Full Text PDFJ Org Chem
March 2024
Guangxi Key Laboratory of Drug Discovery and Optimization, Guangxi Engineering Research Center for Pharmaceutical Molecular Screening and Druggability Evaluation, Key Laboratory of Medical Biotechnology and Translational Medicine, School of Pharmacy, Guilin Medical University, Guilin 541199, Guangxi, China.
A simple and efficient visible-light-promoted selenylation/cyclization of -alkynyl benzylazides/-propargyl arylazides have been realized for the practical synthesis of seleno-substituted isoquinolines and quinolines. This strategy provides the synthesis of valuable seleno-substituted isoquinoline and quinoline derivatives via the construction of one C(sp2)-Se bond and one C-N bond within one process.
View Article and Find Full Text PDFJ Org Chem
March 2024
Faculty of Pharmaceutical Sciences, Toho University 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
A palladium-catalyzed cyclization-carbonylation of 2-alkynyl primary benzamides afforded methyl 3-substituted 1-methoxyisoquinoline-4-carboxylates in good to moderate yields. In the case of mesylate , was obtained directly via a cyclization-carbonylation-cyclization cascade. Compounds were converted to isoquinolin-1(2)-ones in good yields under microwave irradiation.
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