Sigmatropic rearrangement of adducts from ipso-nitration: formation of adducts containing a secondary nitro-group
Abstract
The regiospecific and stereospecific rearrangement of 3-chloro-6 methyl-6-nitrocyclohexa-2,4-dienyl acetate (and related adducts) to 5-chloro-2-methyl-6-nitrocyclohexa-2,4-dienyl acetate (and analogues) and of 2-cyano-4,5-dimethyl-4-nitrocyclohexa-2,5-dienyl acetate (and its 3,4-dimethyl isomer) to 2-cyano-4,5-dimethyl-6-nitrocyclohexa-2,4-dienyl acetate (and its 3,4-dimethyl isomer) appear to involve [1,5] and [1,3] sigmatropic nitro-shifts, respectively.