An easy and efficient zirconium-mediated synthesis of allylamines from simple amines and enol ethers is described. This strategy also allows the synthesis of amino alcohol derivatives containing a Z double bond in their structure when 2,3-dihydrofuran is used. Simple conventional modification of these amino alcohols leads to 2-substituted piperidine derivatives. By applying this approach, a formal total synthesis of the alkaloid coniine is easily achieved from a protected butylamine. Finally, the zirconium-mediated reaction of amines and allyl phenyl ether furnishes homoallylamines or amino ethers depending on the structure of the starting amine.

This tutorial review surveys recent advances in the field of zirconium promoted coupling reactions of unsaturated molecules (and/or organolithium compounds) and heterosubstituted alkenes. This reaction has recently emerged as a powerful tool in organic chemistry to access a variety of synthetically useful building blocks not easily available by other methods. In particular, three different reaction pathways are discussed: i) the reaction involving alkyne-zirconocene and aryne-zirconocene complexes which allows access to dienyl and aryl zirconocene complexes; ii) the reaction of alkene-zirconocene complexes and enol ethers which has shown to be highly dependent on the structure of the enol ether used, allowing the synthesis of simple vinyl zirconocenes or multicomponent coupling products, and; iii) the reaction involving imine-zirconocene complexes which supposes a new entry to allylic amines.

A new regio- and stereoselective zirconocene-catalyzed reaction for the synthesis of medium-sized rings is described. The global reaction supposes a formal ring expansion of a cyclic enol ether to give a functionalized carbocycle.

Unexpected results are obtained on treatment of alkene–zirconocene complexes with cyclic enol ethers. The ring size of the enol ether makes the reaction proceed through different mechanisms allowing Z alkenols to be prepared from furan derivatives and cyclobutanes from pyran derivatives (see scheme).

A diastereoselective synthesis of 1,3-butadiene or cyclobutene derivatives by a zirconium-mediated reaction of alkenyllithium compounds and vinyl bromides is reported. The key steps involve the generation of zirconocene-alkyne complexes from haloalkenes and subsequent coupling with alkenyl bromides. Thus, formally the process supposes the cross-coupling reaction between a terminal alkyne and an alkenyl bromide. Moreover, the use of butyl vinyl ether instead of vinyl bromide as the unsaturated system allows an alternative access to different 1,3-butadiene regioisomers.