Zeolites in the Synthesis of Terpenyl Amines By Isoprene Telomerization, pp. 625-636
Authors: (E.A. Petrushkina, D.V. Khomishin, N.E. Mysova, A.V. Orlinkov, V.N. Kalinin, Ya.V. Zubavichus, A.A. Veligzhanin - Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, Russia and others)
Abstract: The telomerization of 1,3-dienes with nucleophiles catalyzed by transition metals is an example of the environmentally benign synthetic method. Easily available starting materials are converted in the presence of a catalyst to functionalized octa-2,7-dienes in a 100% atom efficient manner [1, 2]. The use of isoprene in this reaction offers attractive routes to various terpenoid derivatives. The isoprene coupling can occur in a tail-to-tail (t-t), tail-to-head (t-h), head-to-head (h-h) and head-to-tail (h-t) manners (Scheme 1). Along with the 1-substituted 2:1 telomers, 3-substituted products of the same carbon skeleton, 1:1 adducts, and nonsubstituted trienes can be obtained as by-products (Scheme 1). The fractions of possible products depend on the nature of the nucleophile, solvent, temperature and catalyst employed. In the case of alcohols as nucleophiles, only modest selectivity is usually achieved with tailto- head or tail-to-tail telomers dominating. Meanwhile, in the case of amines, all possible skeleton isomers are afforded  and the selection of appropriate palladium complex, ligand, solvent and acid enabled the 60-98% selectivity for the t-t telomer , the 56-89% selectivity for the t-h telomer  and the 73-97% selectivity for the h-h telomer . The worst selectivity of only 40-41% [4c, 5a] was achieved for the h-t telomer with the naturally occurring structure of α-geranylamine.