MODELS OF THE INTERACTION OF FERROCENE-1,1'-DITHIOL AND DIOLEFINS .2. ACID AND BASE-CATALYZED REACTIONS OF FERROCENETHIOLS WITH ACTIVATED OLEFINS

Both ferrocenethiol and ferrocene-1,1'-dithiol, Fe(C5H5)(C5H4SH) and Fe(C5H4SH)(2), add to activated olefins to give 1:1 and 1:2 adducts, respectively. The base-catalysed (NEt(3)) reactions of the monofunctional ferrocenethiol with the mono-olefins methyl methacrylate, methyl vinyl sulfone and benzylidene acetone lead to the expected 1:1 adducts whereas 2:1 adducts are obtained with bifunctional olefins such as divinyl sulfone and dibenzylidene acetone. The corresponding bifunctional ferrocene-1,1'-dithiol gives 1:2 adducts with methyl methacrylate, methyl vinyl ketone and benzylidene acetone. For comparison, the aliphatic 2-fenocenyl-ethanethiol, Fe(C5H5)(C5H4-CH2CH2SH), was reacted with methyl vinyl sulfone and divinyl sulfone. In all cases, the disulfides Fc-SS-Fc and Fc-CH2CH2-SS-CH2CH2-Fc, respectively, are also formed. The acid-catalysed (HCl) reactions of ferrocenethiol and fenocene-1,1'-dithiol, Fe(C5H5)(C5H4SH) and Fe(C5H4SH)(2), with isobutyl vinyl ether produce the expected 1:1 and 1:2 adducts although the formation of dimercaptals is also possible. Thus the reaction of ferrocene-1,1'-dithiol with isobutyl vinyl ether leads to both the 1:2 adduct and the 2-methyl 1,3-dithia-[3]fenocenophane, Fe(C5H4S)(2)CH(CH3), and the HCl-catalysed addition of ferrocenethiol to 1,4-butanediol divinyl ether gives 1,1-di(ferrocenylmercapto) ethane, CH3CH(SFc)(2). The new sulfur derivatives of ferrocene were characterized by H-1 and C-13 NMR spectroscopy.