Collect. Czech. Chem. Commun. 1983, 48, 1864-1866

The mechanism of formation of 2,7-dimethyl-2,6-octadiene in the synthesis of 3-methylene-7-methyl-1,6-octadiene

Jan Bartoňa and Ivan Kmínekb

a Department of Organic Technology, Prague Institute of Chemical Technology, 166 28 Prague 6
b Institute of Macromolecular Chemistry, Czechoslovak Academy of Sciences, 162 06 Prague 6


2,7-Dimethyl-2,6-octadiene is formed in the catalytic solution for the dimerization of 2-methyl-1,3-butadiene to β-myrcene (3-methylene-7-methyl-1,6-octadiene), as revealed by mass spectrometry and 13C NMR spectroscopy. Visual observations together with the results of gas chromatographic analysis of the catalytic solution suggest that the formation of 2,7-dimethyl-2,6-octadiene is associated with the transition of the alkali metal (sodium) from the solid phase into the solution. A reaction pathway is suggested accounting for the formation of 2,7-dimethyl-2,6-octadiene in the system.