Michael addition of amines to sterically crowded ortho-benzoquinone completed with unprecedented 1,2-shift of a tert-butyl group

A strong electron-withdrawing nitro group introduced into the 6-position of 3,5-di-(tert-butyl)-1,2-benzoquinone provides for activation of the sterically blocked Michael addition reaction channel. Addition of amines to the quinone is followed by a concerted 1,2-migration of a tert-butyl group to af...

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Bibliographic Details
Published in:Tetrahedron 2021-01, Vol.79, p.131841, Article 131841
Main Authors: Ivakhnenko, Eugeny, Malay, Vasily, Romanenko, Galina, Demidov, Oleg, Knyazev, Pavel, Starikov, Andrey, Minkin, Vladimir
Format: Article
Language:English
Subjects:
6-Nitrocyclohexa-2,5-dienones
Density functional calculations alkyl 1,2-migration
Michael addition
Quinones
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Summary:A strong electron-withdrawing nitro group introduced into the 6-position of 3,5-di-(tert-butyl)-1,2-benzoquinone provides for activation of the sterically blocked Michael addition reaction channel. Addition of amines to the quinone is followed by a concerted 1,2-migration of a tert-butyl group to afford derivatives of 4-amino-3-nitrocyclohexa-3,5-diene-1,2-dione system. The multistep reaction mechanism was examined using DFT computational methods. [Display omitted] •Michael addition reaction channel blocked in sterically crowded o-quinones is activated.•3,5-di-(tert-butyl)-6-nitro-1,2-benzoquinone reacts with amines to give cyclohexadienones.•The addition reaction is accompanied by 1,2-shift of a tert-butyl group along the ring.•The multistep mechanism of the reaction is unveiled by the DFT study.
ISSN:0040-4020
1464-5416
DOI:10.1016/j.tet.2020.131841