Pd(OAc)₂/Ph₃P-catalyzed dimerization of isoprene and synthesis of monoterpenic heterocycles

Abstract

The palladium-catalyzed dimerization of isoprene is a practical approach of synthesizing monoterpenes. Though several highly selective methods have been reported, most of them still required pressure or costly ligands for attaining the active system and desired selectivity. Herein, we present a simple and economical procedure towards the tail-to-tail dimer using readily available Pd(OAc)2 and inexpensive triphenylphosphine as ligand. Furthermore, simple screw cap vials are employed, allowing carrying out the reaction at low pressure. In addition, the potential of the dimer as a chemical platform for the preparation of heterocyclic terpenes by subsequent (hetero)-Diels–Alder or [4 + 1]-cycloadditions with nitrenes is also depicted.

Thermal cyclodimerization of isoprene for the production of high-performance sustainable aviation fuel

“…For example, dimerization of isoprene with palladium catalysts can yield various acyclic C10 trienes. 35 More recently, Ottosson and co-workers reported a photochemical route to cyclic isoprene dimers. 36 Isoprene can also be effectively dimerized via a [4+4]-cycloaddition catalyzed by an iron pyridineimine (Fe-PDI) catalyst to generate 2,6-dimethyl-1,5-cyclooctadiene (DMCOD).…”

A Study of the Catalytic Properties of Synthetic Aluminosilicates of Different Morphologies in Cracking Reactions of the Byproducts of Isoprene Synthesis

“…The petrochemical processes related to the production of isoprene for the production of synthetic rubbers (SRs), as a rule, are accompanied by the formation of a wide range of byproducts (BPs) (for example, dioxane alcohols, hydropyrans, and esters [1][2][3]). The latter are mainly used as fuel in waste heat boilers and are only partially processed technologically with the useful products being recycled [4].…”