90554-25-9Relevant articles and documents
Stereoselective Two-Step Chemical Preparation of 1,4-Dialkyl-1,4-dimethoxycyclohexa-2,5-dienes
Alonso, Francisco,Yus, Miguel
, p. 7471 - 7476 (2007/10/02)
The reaction of p-benzoquinone (1) with several organolithium compounds (methyl-, ethyl-, n-butyl-, phenyllithium) led, after hydrolysis with water, to the corresponding crude diols 4, which were successively treated with sodium hydride and methyl iodide yielding the expected 1,4-dialkyl-1,4-dimethoxycyclohexa-2,5-dienes 2a-d in a stereoselective manner.The use of a tandem process with two different organolithium reagents followed by methylation by the same procedure yielded stereoselectively the mixed 1-alkyl-4-alkyl' derivatives 2e,f.
Reactions of the 1-hydroxy-1,4-dimethylcyclohexadienyl cation, an intermediate in the solvolysis of 1,4-dimethyl-4-nitrocyclohexa-2,5-dien-1-ol
Fischer, Alfred,Henderson, George N.,Smyth, Trevor A.
, p. 1093 - 1101 (2007/10/02)
Solvolysis of 1,4-dimethyl-4-nitrocyclohexa-2,5-dien-1-ol in mixed aqueous organic solvents gives the diastereomers of 1,4-dimethylcyclohexa-2,5-dien-1,4-diol, 1,4-dimethylcyclohexa-3,5-diene-1,2-diol, 2-nitro-p-xylene, 2,4-dimethylphenol (all derived from the title cation, itself formed by ionization of the nitro group as nitrite), and 2,5-dimethylphenol.In aqueous methanol the diastereomers of 4-methoxy-1,4-dimethylcyclohexa-2,5-dienol are also obtained.Significant yields of 2,5-dimethylphenol are only obtained on the acid-catalyzed further reaction of the dienediol (or the methoxydienol) and involve the intermediate formation of 1,4-dimethylcyclohexa-3,5-diene-1,2-diol.In the absence of added base the acid released in the solvolysis catalyses this reaction and leads to the aromatization of the dienes.
