Abstract
Condensation of anilines and primary aliphatic amines with 3,4-diphenylcyclo-2-pentenone leads to the corresponding diphenylcyclopentene imines in good yields of 72-90%. Deprotonation of these aminocyclopentadiene tautomers and reaction with FeCl2 leads to the synthesis of the respective 1,1'-diamino-3,3',4,4'-tetraphenylferrocenes. Yields increase from 33% to 65% with a decrease in the steric bulk of the amine substituent. The observation that a successful conversion requires two equivalents of base is conceived on the basis of the discussed reaction mechanism. The molecular structure of 1,1'-dianilino-3,30,4,40-tetraphenylferrocene ( 3a), which was determined by single crystal X-ray analysis reveals a trans coordination of the two amine moieties with respect to the central Cp-Fe-Cp axis of the ferrocenyl backbone. (C) 2007 Elsevier B. V. All rights reserved.