Garg P, Upreti GC, Singh A. Synthesis of Tritylones via Cascade Reaction of Arynes with 5-Ethoxyoxazoles.
J Org Chem 2022;
87:7219-7228. [PMID:
35580308 DOI:
10.1021/acs.joc.2c00437]
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Abstract
A cascade reaction involving arynes and 5-ethoxyoxazoles has been developed toward the synthesis of 9-alkyl/aryl tritylones. 5-Ethoxyoxazoles undergo a [4 + 2] cycloaddition reaction with arynes followed by retro-[4 + 2] cycloaddition, a second intermolecular [4 + 2] cycloaddition reaction, and hydrolytic ring cleavage to generate substituted tritylones in good yields. The conversion of tritylone products to a series of spirocyclic anthrone derivatives has been demonstrated. The reaction is expeditious, exhibits wide scope, and employs readily available starting materials.
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