Synthesis of poly-ferrocene heterocycles by cycloaddition of mono- or bis(ferrocenecarbonyl)acetylenes and bis[1,2]dithiolo[1,4]thiazinethiones

Cycloaddition of a bis[1,2]dithiolo[1,4]thiazine ketothione and mono- or bis(ferrocenecarbonyl)acetylenes under catalysis by scandium triflate gave mono- and bis-ferrocenecarbonyl-1,3-dithiolylidene[1,2]dithiolo[1,4]thiazines. Cycloaddition of a bis-dithiolothiazine dithione and bis-ferrocenylbutynedione gave 3,5-di(bis-ferrocenecarbonyl-1,3-dithiolylidene)[1,4]thiazine, a structure related to extended tetrathiafulvalenes