PREPARATION OF 2,5-DIMETHYL-3-(2-METHYL-1-CYCLOHEXENYL)-4-THIOPHENECARBOXYLIC ACID AND 2,5-DIMETHYL-3-(2-METHYL-2,6-CYCLOHEXADIENYL)-4-THIOPHENECARBOXYLIC ACID

Some presumptively optically active (atropisomeric) thiophene derivatives with a 2-methyl-1-cyclohexenyl group at the 3-position have been prepared by reacting a 3-thienyllithium compound with 2-methylcyclohexanone, followed by the elimination of water from the resulting tertiary alcohol. A method for directing the elimination reaction has been worked out. The title compounds were obtained starting from 3,4-dibromo-2,5-dimethylthiophene and 2-methyl-cyclohexanone and 2-methyl-2-cyclohexenone, respectively.