Ferrocenyl substituted chlorostilbenes and butadienes

The readily accessible alpha -chlorophosphonates (OCH2CMe2CH2O)P(O)CH(Cl)-C 6H4-4-R [1: R = Me (a), OMe (b), Cl (c), H (d)] react with ferrocenecarboxa ldehyde in the presence of NaH [Horner-Wadsworth -Emmons reaction] to give good yields of ferrocenyl substituted chlorostilbenes. The novel bis ferroc enyl butadiene C5H5FeC5H4-CH=CH-C(CN)CHC5H4FeC5H5 (9) as well as the ferroc enyl 2-cyano-1,3-butadienes 4-R-C6H4-CH=CH-C(CN)=CHC5H4FeC5H5 [R = Me (10a) , OMe (10b), Cl (10c)] have been obtained by using the new allylphosphonate (OCH2CMe2CH2O)P(O)CH2C(CN)=CHC5H4FeC5H5 (8); the latter compound was prepa red in good yields by the reaction of the Baylis-Hillman adduct, C5H5FeC5H4 CH(OH)C(CN)=CH2 (7), with the chlorophosphite (OCH2CMe2CH2O)PCl. The electr ochemical behavior of the ferrocenyl compounds thus synthesized has been st udied: two reversible one-electron processes are observed in the case of co mpound 9 suggesting a cooperative interaction between the two ferrocenyl re sidues. (C) 2001 Elsevier Science B.V. All rights reserved.