X-Ray structural investigation of 1,3,6-trichloro-3,6-dimethylcycloheptanecarbonitrile and 2,5-dimethyl-2,5-dichlorohexane — Products of the reaction of 2,5-dimethyl-1,5-hexadiene with trichloroacetonitrile

Addition of trichloroacetonitrile to 2,5-dimethyl-1,5-hexadiene in the presence of cuprous amine complexes is studied. Single crystal X-ray diffraction unambiguously proves that the main product is a racemic mixture of the cyclic symmetric nitrile: (1r,3R,6S)-and (1r,3S,6R)-1,3,6-trichloro-3,6-dimethylcycloheptanecarbonitrile. Established relative configuration of the product confirms the ring closure mechanism suggested before. Also, a side product 2,5-dimethyl-2,5-dichlorohexane is isolated (the product of hydrochlorination of the starting alkadiene). Low-temperature (190 K) structural examination of this centrosymmetrical molecule indicates that the unit cell comprises one molecule.