A palladium-catalyzed direct C-H arylation of indolines at C-7 position has been achieved at near-ambient temperature. The reaction was carried out with aryltriazene as a stable aryl source and electron shuttle to sustainably release aryl radical under the action of promoter, and pyrimidine as a detachable directing group for the synthesis of 7-arylindolines under oxidant- and ligand-free conditions. Notably, this catalytic system can also be applied to the direct and site-selective arylation of tetrahydroquinolines (C-8) and carbazoles (C-1).
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http://dx.doi.org/10.1021/acs.joc.3c01022 | DOI Listing |
Org Biomol Chem
September 2024
Department of Chemical Sciences, Tezpur University, Napaam, Tezpur, Assam, India 784028.
2-(2-Nitrobenzyl)-2-(2-nitrophenyl)malonates, readily prepared by SAr-arylation of diethyl malonate with -fluoronitrobenzenes, followed by S2-alkylatioin of the resulting products with -nitrobenzyl bromides, undergo a tandem Fe/AcOH-promoted nitro-reduction and double lactamization sequence to afford spiro[indoline-3,3'-quinoline]-2,2'-diones in high overall yields. The method is operationally simple, economical, and has a broad substrate scope. The synthetic practicality of this methodology was illustrated by performing the reaction on a gram scale with the same efficiency.
View Article and Find Full Text PDFJ Org Chem
September 2024
School of Pharmacy, China Medical University, Taichung 406040, Taiwan.
Org Lett
June 2024
Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Materials Science, Zhejiang Normal University, Jinhua 321004, China.
A method for direct construction of cyclopenta[]indolines via a photocatalytic fluoroalkylative radical cyclization cascade of ynamides has been established, which proceeds via a sequence of radical addition, 1,5-HAT, 5-- cyclization, intramolecular arylation, and oxidative deprotonation. This protocol allows for the controllable assembly of a tricyclic architecture with three contiguous stereocenters, showcasing its high efficiency, compatibility, and regio- and diastereoselectivity for accessing pharmacologically significant fluoroalkylated cyclopenta[]indolines. It represents one of the very few examples of tetrafunctionalization of alkynes.
View Article and Find Full Text PDFOrg Lett
March 2024
College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Chaowang Road 18#, Hangzhou 310014, China.
A palladium-catalyzed dearomative diarylation of C2-deuterated or C2-nonsubstituted indoles through domino Heck/Suzuki coupling is established. Relying on electron-deficient phosphite ligand, side reactions including intermolecular Suzuki coupling and intramolecular C-D/H arylation are inhibited and a wide range of 2,3-diarylated indolines bearing vicinal tertiary stereocenters including deuterated ones are afforded in moderate to excellent yields (up to 94%) and excellent diastereoselectivities (>20:1). The catalyst loading can be lowered to 0.
View Article and Find Full Text PDFPhotochem Photobiol
January 2024
Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune, India.
Squaraine dyes possess sharp far-red active transition with high extinction coefficient and form aggregates on TiO surface. Aggregation of dyes on TiO has been considered as a detrimental factor for DSSC device performance, which can be controlled by appending alkyl groups to the dye structures. Hence by integrating alkylated (alkyl groups with both in-plane and out-of-plane) aryl group with indoline moiety to make it compatible with other electrolytes and for controlling the dye-aggregation, a series of squaraine acceptor-based dyes SQA4-6 have been designed and synthesized.
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