SYNTHESIS AND CHARACTERIZATION OF NEW PERFLUOROALKYLATED SIDE-CHAIN FERROCENES AND FERRICINIUM SALTS

The synthesis and characterization of various mono- and 1,1'-bis-[omeg a-(F-alkyl)acyl]ferrocenes, 1,1'-bis-[omega-(F-alkyl)alkyl]ferrocenes and -[omega-(F-alkyl)-alpha-(hydroxy)-alkyl]ferrocenes are described ( where F-alkyl denotes perfluoroalkylation). The [(F-alkyl)acyl]ferroce nes were obtained by Friedel-Crafts acylation of ferrocene with (F-alk yl)acyl chlorides. The (F-alkyl)alkyl and (F-alkyl)-alpha-(hydroxy)alk yl analogues were selectively prepared by reduction of the acyl deriva tives with LiAIH(4)-AlCl3 and LiAlH4 respectively. These reactions ill ustrate the chemical inertness of (F-alkyl)acyl and (F-alkyl)alkyl cha ins under strongly reducing conditions. When the acylation of ferrocen e was performed with omega-[2-(F-alkyl)ethenyl]acyl chlorides, acylfer rocenes were obtained but their side chains contained the (Z)-CF=CH-CH (Cl)- sequence. Formation of these chains resulted from a highly stere ospecific (E)-CF2-CH=CH- to (Z)-CF=CH-CH(Cl) transformation, which inv olves an F-Cl exchange and a double-bond migration in the [2-(F-alkyl) ethenyl]acyl chain. The 1,1'-bis-[11-(F-alkyl)undecanoyl]ferrocenes we re found to be most effectively oxidized to the corresponding ferricin ium species by HBF4-p-benzoquinone, while their hydrocarbon analogue 1 ,1'-bis-[undecanoyl]ferrocene underwent a Michael addition to give ben zofuranylferrocenes.