Cyclophanes, XXXVIII. [2]Metacyclo[2]indenophanes: Synthesis, Anions and Iron Complexes

[2.2]Metacyclophane can be directly formylated according to the Rieche method to give 4‐formyl[2.2]metacyclophane ( 12 ) in 44% yield. The synthesis of the [2]metacyclo[2]indenophane 8 from the aldehyde 12 by the pathway previously employed for the corresponding [2.2]paracyclophanes failed due to the harsh conditions of the cyclization step. An alternative synthesis of 8 and its isomer 9 involving the construction of the five‐membered ring prior to that of the cyclophane unit succeeded. Compounds 8 and 9 were obtained as an 82:18 mixture, deprotonation of which afforded the anion 10 , which shows long‐term stability. The 1 H‐NMR spectrum of this anion does not exhibit a through‐space charge transfer due to its structure. The 1 H‐NMR parameters and molecular mechanics calculations are discussed. Both faces of 10 react in the presence of FeCl 2 · 2 THF and a twentyfold excess of LiCp to give a 70:30 mixture of the ferrocene derivatives 7 and 35 .