Reactions of conjugated arylazocyclohexenes with Grignard reagents. Part 2. A new stereospecific route to 2-alkyl- and 2-aryl-cyclohexanones

Abstract

4-Methyl- and 4-t-butyl-1-arylazocyclohexenes react with aliphatic and aromatic Grignard reagents, to furnish, after oxidative hydrolysis of the intermediate aryihydrazones, 2-alkyl-4-methyl-, 2-aryl-4-methyl-, 2-alkyl-4-tbutyl-, and 2-aryl-4-t-butyl-cyclohexanones, with a trans-configuration. From the reactions with o-tolyl- and α-naphthyl-magnesium bromide only the cis-isomers were obtained. The structures of the products were, determined by spectroscopic methods and by epimerization of the trans-cyclohexanones into the more stable cis-isomers.