New Phenoxy[4]ferrocenophanedienes: First Case of a Boat Conformation of a Diazacyclohexene 1,4-Capped by a Ferrocene

Some new aryloxy[4]ferrocenophanedienes are described, which have been obtained by reaction of 1,1′-di(1-propynyl)ferrocene and respective phenols. These include one case of a twofold reaction of this type. The possibility of using the products as substrates in Diels-Alder cycloadditions was evaluated with the result that only the most reactive dienophile, 4-phenyl-1,2,4-triazoline-3,5-dione, underwent this reaction. The cycloadduct has an unprecedented structure in that the ferrocene moiety 1,4-diaxially caps a boat conformer of a cyclohexane moiety.