ORGN 8 |
| Gerhard Erker, Universität Münster, Corrensstrasse 40, Münster, 48149, Germany |
| (Butadiene)zirconocenes are readily formed e.g. upon treatment of a great variety of zirconocene dihalides with the "butadiene-magnesium" reagent. Both, the s-cis- and the s-trans-conjugated diene bent metallocene isomers react readily with a variety of electrophilic reagents. Upon treatment with nitriles (2 equivalents) the organometallic precursors of stable primary enamines, the corresponding 1,6-diaminohexatrienes, are formed. The reaction with metal carbonyls yields O-zirconated Fischer carbene complexes, that have served as precursors for the synthesis of remotely functionalized unsaturated carboxylic acids. The strong Lewis acid tris(pentafluorophenyl)borane adds to the (butadiene)zirconocenes to yield zwitterionic complexes that are active homogeneous Ziegler-Natta olefin polymerization catalysts. They have allowed for the experimental observation of the first olefin insertion steps in the initiation sequence of the catalytic process. Some mechanistic features of these reactions will be discussed. |
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Half-A-Century of Organozirconium Chemistry
9:00 AM-12:00 PM, Sunday, March 28, 2004 Anaheim Convention Center -- Ballroom C, Oral
Division of Organic Chemistry |