Effect of the amine structure on the course of linear anionic-coordination dimerization of isoprene in the presence of dialkylamine and sodium

Abstract

The effect was studied of the structure of the amine on the course of linear anionic-coordination dimerization of isoprene (2-methyl-1,3-butadiene) to β-myrcene (3-methylene-7-methyl-1,6-octadiene) in tetrahydrofuran solution in the presence of dialkylamine and sodium. The modified Taft-Pavelich equation was used to express this effect quantitatively. The selectivity of the reaction to β-myrcene was found to depend above all on the polar properties of the substituents R1, R2 of the dialkylamine use, described by the Σσ* parameter, while the reaction rate of the formation of β-myrcene depended more on their steric properties, expressed by the ΣEs parameter.