Synthesis of [1,1]Ferrocenophanes via 1,1'-Bis(6-fulvenyl)ferrocene

An efficient and practical synthesis of [1.1] ferrocenophane is described. The sequence of reactions starts with 1,1-dilithioferrocene, which is added to 6-dimethylaminofulvene, producing, after hydrolysis, the previously unknown 1,Vbis(6-fulvenyl)ferrocene in better than 80% yield. Other procedures for the preparation of the compound are also given. The fulvene is reduced with lithium tri(sec-butyl)borohydride in THF to the 1,1-bis(cyclopentadienylmethyl)ferrocene dianion, from which the [1.1] ferrocenophane is obtained by reaction with ferrous chloride in THF in average yield of 35 to 45% after purification. Thus, the ferrocenophane is available for the first time through a satisfactory preparative method in large enough quantities to investigate its chemistry. From the intermediates used in this synthesis, substituted ferrocenophanes can also be obtained. © 1981, American Chemical Society. All rights reserved.