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Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Visible Light-Mediated In Situ Generation of δ,δ-Disubstituted p-Quinone Methides: Construction of a Sterically
Arun Sharma1, Vikas Dixit1, Sharvan Kumar1
1Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, 110016 New Delhi, India.
Abstract:
An unprecedented visible light-assisted and zinc triflate-catalyzed construction of a diaryl-substituted quaternary stereocenter is reported. 2-(4-Hydroxyphenyl)-substituted aldehydes and ketones have been prepared in moderate to high yields via multicomponent reaction of acetylene, benzoquinone (BQ), and indole/aniline/thiol. The reaction is believed to proceed via in situ generation of p-quinone methide through a [2+2] cycloaddition-retroelectrocyclization of BQ and acetylene in blue light followed by a zinc triflate-catalyzed vinylogous Michael addition reaction with nucleophiles.
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