Layered π Systems Based on Ferrocenophanes

[1.1]Ferrocenophane was prepared by the literature method along with a small amount of [1.1.1.1]ferrocenophane, which was for the first time characterized by a crystal structure analysis. Oxidation of [1.1]ferrocenophane with DDQ afforded [1.1]ferrocenophane‐1,12‐dione. Here, new results of the chemistry of this compound are reported. One electron oxidation gave the mixed valence Fe(II)/Fe(III) monocation, which was characterized by its Mößbauer spectrum. Knoevenagel condensations of [1.1]ferrocenophane‐1,12‐dione with malonodinitrile and cyanoacetic acid esters in the presence of a Lewis acid gave a number of mono‐ and di‐condensation products, all of which showed a syn conformation. While condensations with malonodinitrile afforded the mono‐ and the di‐condensation products, less symmetric substrates such as tert ‐butyl cyanoacetate gave mixtures of diastereomers. At elevated temperatures decarboxylation reactions gave cyanomethylene substituted [1.1]ferrocenophane derivatives as diastereomeric mixtures, which could chromatographically be separated. An attempted McMurry reaction of [1.1]ferrocenophane‐1,12‐dione did not result in an intramolecular coupling but in an intermolecular combination. Finally, the reduction of [1.1]ferrocenophane‐1,12‐dione with lithium tetrahydridoaluminate followed by aqueous work up gave a small yield of an intramolecular etherification product. In eight cases, the reaction products were characterized by crystal structure analyses.