The coupling reaction of allylic halides to produce non-conjugated dienes was investigated. It was found that iron powder could be utilized, without any special pretreatment, to promote the coupling reaction when a dipolar aprotic solvent was employed as the rcaction medium.Effects of variables such as thc nature of the halogen atom in the reactive position of the substrate, substituents on the substrate, Dresence or absence of organic or inorganic halide catalysts, and solvent type were explored briefly.Non-conjugated dienes can be prepared in yields which exceed 90% in the Inore favorable cases. The present procedure avoids many of the difficulties inherent in such previous rnetl~ods as the Grignard reaction or the nickel carbonyl-promoted reaction.

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Isopren (V) wird gewonnen durch Reaktion von Formaldehyd (I) mit Methanol/HCl zum Chlormethyl‐methyläther (II) und dessen Umsetzung mit Isobutylen (III) zu 3‐Chlor‐3‐methyl‐butyl‐methyläther (IV), der zu (V) pyrolysiert wird.