Semimasked 1,1′-diethynylferrocenes: synthetic concepts, preparations, and reactions
作者:Herwig Schottenberger、Josef Lukassser、Erwin Reichel、Adrian Gallus Müller、Georg Steiner、Holger Kopacka、Klaus Wurst、Karl Hans Ongania、Karl Kirchner
DOI:10.1016/s0022-328x(01)00975-5
日期:2001.12
Due to the inherent instability of 1,1'-diethynylferrocene, the respective coupling chemistry for the access of oligonuclear systems requires stepwise preparative sequences involving consecutive ethyne deprotection, or the conversion of latent ethyne precursor functionalities, respectively. The new derivatives 1-acetyl-1'-ethynylferrocene, 3, and, preferably, 1-ethynyl-1'-formylferrocene, 9, turned out to be the most favorable starting compounds. The subsequent synthetic chemistry, as well as the X-ray structures of selected starting and target derivatives are presented. A unique intramolecular coupling product, 12, represents the first ladder-type tricyclic metallocenophane system exhibiting high ring strain. Supplementary novelties concerning monoacetylenic parent systems are also presented. (C) 2001 Elsevier Science B.V. All rights reserved.