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

Abstract

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