Formation of functionalized [3]ferrocenophane derivatives by an enamine condensation reaction (vol 586, pg 218, 1999)

Treatment of 1,1'-diacetylferrocene (10) with excess piperidine and a stoichiometric amount of TiCl4 in pentane leads to CC-coupling of the two functional groups at the ferrocene framework. This enamine condensation reaction leads to the formation of the 1,3-connected dienamine-bridged [3]ferrocenophane system 13a. Complex 13a was characterised by X-ray crystal structure analysis. The analogous TiCl4-mediated coupling and condensation reactions of 10 with morpholine. pyrrolidine or methyl-isopropylamine yield the corresponding substituted [3]ferrocenophane systems 13b-d. (C) 2000 Elsevier Science S.A. All rights reserved.