Ipso nitration. XXII. The stereochemistry of 1,4-dimethyl-4-nitrocyclohexa-2,5-dienols and their acetates and methyl ethers

Abstract

The higher melting isomer of 1,4-dimethyl-4-nitrocyclohexa-2,5-dienol has the (E)-configuration. The stereospecific interconversion of the dienols and the corresponding acetates and the stereospecific conversion of dienols to methyl ethers allow the assignment of the configurations of the isomeric acetates and ethers. Parallels in physical properties allow the assignment of the stereochemistry of the isomers of 1-alkyl-4-methyl-4-nitrocyclohexa-2,5-dienyl acetates (alkyl = Et, i-Pr, t-Bu) and of 1-alkyl-4-ethyl-4-nitrocyclohexa-2,5-dienyl acetates (alkyl = Me, Et).