Preparation and some chemistry of ferrocenylethynyl ketones

Reactions of Fc′(CHO)21 (Fc′ = 1,1′-ferrocenediyl) with LiCtriple bond; length of mdashCR gave substituted propargylic alcohols Fc′{CH(OH)Ctriple bond; length of mdashCR}2 (R = SiMe32, Fc 9). Oxidation (MnO2) of these alcohols afforded the bis(alkynyl ketone)s Fc′{C(O)Ctriple bond; length of mdashCR}2 (R = SiMe33, Fc 10), the former being accompanied by the partially desilylated Fc′{C(O)Ctriple bond; length of mdashCH}-1-{C(O)Ctriple bond; length of mdashCSiMe3}-1′ 4. The reaction between 4 and RuCl(dppe)Cp in the presence of Na[BPh4] gave the cyclic vinylidene complex [Ru{double bond; length as m-dashCdouble bond; length as m-dashC[C(O)Fc′C(O)CHdouble bond; length as m-dashCH]}(dppe)Cp]BPh45. The diastereomers were separated by flash chromatography (2) or preparative t.l.c. (9) to give the cis (2a, 9a) and trans (2b, 9b) isomers. Cyclisation of each isomer to the corresponding ferrocenophane was catalysed by pTSA to give Fc′{[CH(Ctriple bond; length of mdashCR)]2O} (R = SiMe36a, 6b; Fc 11a, 11b), of which 6a, 6b could be desilylated to Fc′{[CH(Ctriple bond; length of mdashCH)]2O} 7a, 7b, and further transformed into the bis(η2-alkyne-dicobalt) complexes Fc′{[CH(η2-C2H[Co2(μ-dppm)(CO)4])]2O} 8a, 8b with Co2(μ-dppm)(CO)6. Molecular structures of 3, 5, 6a, 6b, 7a, 7b and 10 were determined by single-crystal XRD methods.