研究室工作进展 Sep. 13th, 2013.
Alkaline-Earth Metallocenes Coordinated with Ester Pendants: Synthesis, Structural Characterization, and Application in Metathesis Reaction
Heng Li, Wen-Xiong Zhang, and Zhenfeng Xi*
Chem. Eur. J. 2013, 19, 12859-12866.
A variety of ester-substituted cyclopentadiene derivatives were synthesized in one-pot from the reaction of 1,4-dilithio-1,3-butadienes, CO and acid chlorides. Direct deprotonation of the ester-substituted cyclopentadienes with Ae[N(SiMe3)]22 (Ae = Ca, Sr, Ba) efficiently generated a new type of heavier alkaline-earth (Ca, Sr, Ba) metallocenes in good to excellent isolated yields. Single-crystal X-ray structural analysis demonstrated that these heavier alkaline-earth metallocenes were featured with two intramolecularly coordinated ester pendants and multiply substituted cyclopentadienyl ligands. Their corresponding transition metal metallocenes, such as ferrocene derivatives and half-sandwich cyclopentadienyl tricarbonylrhenium complexes, could be generated highly efficiently via metathesis reactions. The multiply substituted cyclopentadiene ligands containing an ester pendant, and their corresponding heavier alkaline-earth and transition-metal metallocenes would have further applications in coordination chemistry, organometallic chemistry and organic synthesis.
背景介绍
近年来重碱土金属（heavier alkaline-earth，包括钙，锶，钡）配合物的合成、结构与催化应用研究受到重视。但是，这些配合物的高活性（不稳定性）和很差的溶解性阻碍了其进一步研究。 寻找合适的配体以生成稳定的配合物并增加其溶解度成为重要研究方向。本工作利用我们自己发展的反应（Angew. Chem. Int. Ed. 2009, 48, 8111; Chem. Eur. J. 2011, 17, 7399.），合成了一系列酯基取代的环戊二烯配体。利用这些配体合成了重碱土金属(Ca, Sr, Ba)配合物，并初步研究了这些配合物的反应性。预期这些配体及其金属配合物将有更多独特的应用。