Preparation and Reactivity of Acylzirconocene Derivatives

In this case, the presence of the free phenolic hydroxyl group at the ortho position (and also in the para-position) of benzylidene moieties served to fill the role of protic additive in the reaction. 

The reactivity of these unmasked acylzirconocenes can also be increased by transmetaUation reactions as described in the following scheme. 

The reaction proceeds via an acylzirconocene chloride species, formed in situ, and the subsequent Cu(I) (3 mol%) atalyzed coupling reaction gives the corresponding a-ethyl selanyl-substituted vinyl alkynyl ketone derivative. The stereochemistry is maintained during the coupling reaction [40]. 

This strategy has been further developed for the preparation of several iminoa-cyl complexes that have found extensive applications in the synthesis of polycyclic derivatives [42]. 

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