Preparation of Functionalized Alkenylzirconocene Derivatives

Copyright 2005 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 3-527-31131-9 

In general, the functional group compatibility of the process is limited by the oxophilic, hard Lewis-acid character of the Schwartz reagent. The following examples demonstrate the scope of this tolerance. 

Treatment of Cp2ZrCl2 with LiEtjBH in THF leads also to the formation of Cp2Zr(H)Cl Subsequent introduction of terminal acetylenes gives the hydrozirconation reaction without compromising the acid-sensitive functionality present in 

Indeed, intra-or intermolecular chelation shuts down ligand exchange with Me2CuCNLi2 and, hence, vinylcuprate formation. 

The stereodefmed Sn/Zr reagent can be selectivity transmetallated at the zirconium center to afford the corresponding cuprate that react in a clean Sn2 reaction with allylbromide. The functionalized Z-vinyl tin derivative is therefore easily formed in 75% yield. 

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