Cationic cobalt-catalyzed [1,3]-rearrangement of -alkoxycarbonyloxyanilines.

A cationic cobalt catalyst efficiently promoted the reaction of -alkoxycarbonyloxyanilines at 30 °C, affording the corresponding -aminophenols in good to high yields. As reported previously, our mechanistic studies including oxygen-18 labelling experiments indicate that the rearrangement of the alkoxycarbonyloxy group proceeds in [1,3]-manner. In this article, we discuss the overall picture of the cobalt-catalysed [1,3]-rearrangement reaction including details of the reaction conditions and substrate scope.

Cationic N-Heterocyclic Carbene Copper-Catalyzed [1,3]-Alkoxy Rearrangement of N-Alkoxyanilines.

The [1,3]-alkoxy rearrangement reactions of N-alkoxyanilines were efficiently catalyzed by cationic N-heterocyclic carbene (NHC)-Cu catalysts in affording 2-alkoxyaniline derivatives in good to excellent yields with high functional group compatibility. For N-alkoxyanilines having an electron-withdrawing substituent at the meta-position, the alkoxy group selectively migrated to the more hindered ortho-position. In contrast, the alkoxy group migrated to the less hindered ortho-position for N-alkoxyanilines having an electron-donating substituent.

Concerted [1,3]-Rearrangement in Cationic Cobalt-Catalyzed Reaction of O-(Alkoxycarbonyl)-N-arylhydroxylamines.

O-(Alkoxycarbonyl)-N-arylhydroxylamines were efficiently converted to 2-aminophenol derivatives by cationic cobalt catalysts at 30 °C. The results of O-labeling experiments suggested that rearrangement of the alkoxycarbonyl group from the aniline nitrogen to the ortho position proceeded in an unprecedented [1,3] manner.