We reveal a direct strategy for the flexible synthesis of C2-aryl/heteroaryl indoles without transition metal catalysts. The synthesis involves a one-pot, four-component reaction of readily available starting materials to offer diversity around the indole moiety with a broad substrate scope and high yields. The reaction proceeds via the Friedel-Crafts C-arylation of C-acylimine formed , followed by N-arylation with aryne, a formal [3+2] cycloaddition, and a subsequent aromatization cascade.
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http://dx.doi.org/10.1021/acs.joc.2c01753 | DOI Listing |
J Org Chem
January 2025
School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, P. R. China.
In this study, a metal-free and efficient method for the synthesis of sulfilimines and -sulfanylanilines in high yields with excellent chemoselectivities from oxonium aryne precursors with sulfenamides has been developed. This method features mild reaction conditions, simple operations, a general substrate scope, and good tolerance of functional groups. In addition, scale-up synthesis, related applications, and preliminary mechanistic explorations were also investigated.
View Article and Find Full Text PDFChem Sci
August 2024
Organisch-Chemisches Institut, Universität Münster Corrensstraße 40 48149 Münster Germany
Radical transformations with arynes represent an underexplored research field and only a few examples have been disclosed. In this research article, the implementation of arynes in three-component reactions with TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl) and activated alkenes is demonstrated. TEMPO is added to arynes, which triggers a Meerwein-type arylation cascade where the final alkyl radial is eventually trapped by a second equivalent of TEMPO.
View Article and Find Full Text PDFChemistry
August 2024
Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Chemistry, IGCME, Sun Yat-sen University, 510275, Guangzhou, Guangdong, China.
Benzyne derived from hexadehydrogenated Diels Alder (HDDA) reactions was found to be an efficient hydrosilylation acceptors. Various silanes can react smoothly with HDDA-derived benzyne to give the arylation products. Lewis acid such as boron trifluoride etherate can accelerate these hydrosilylation reactions.
View Article and Find Full Text PDFNat Commun
April 2024
School of Chemistry and Chemical Engineering, Chongqing University, 174 Shazheng Street, Chongqing, 400030, PR China.
Arynes are known to serve as highly reactive benzene-based synthons, which have gained numerous successes in preparing functionalized arenes. Due to the superb electrophilic nature of these fleeting species, however, it is challenging to modulate the designated aryne transformation chemoselectively, when substrates possess multiple competing reaction sites. Here, we showcase our effort to manipulate chemoselective control between two major types of aryne transformations using either 3-methoxybenzyne or 3-silylbenzyne, where nucleophilic addition-triggered reactions and non-polar pericyclic reactions could be differentiated.
View Article and Find Full Text PDFJ Org Chem
April 2024
National and Local Joint Engineering Research Center for Green Preparation Technology of Biobased Materials, School of Chemistry and Environment, Yunnan Minzu University, Kunming 650500, P. R. China.
Reactions allowing chemodivergence prove to be attractive strategies in synthetic organic chemistry. We herein described a highly practical, transition-metal-free, highly regioselective and chemodivergent cascade reaction controlled by fluorine sources, which involved a [3 + 2] cycloaddition or -arylation process between aryne precursors and 3-aminomaleimides. These two pathways led to a wide scope of structurally diverse pyrrolo[3,4-]indoles (19 examples) and 3-arylated maleimides (25 examples) in good-to-excellent yields.
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