Construction of extended and polymeric 1,3-dithiolane and tetrathiafulvalene derivatives using cycloaddition of Buⁿ₃P•CS₂

Cycloaddition of the adduct between Bu(3)(II)P and CS2 to strained double bonds such as in norbornene gives novel zwitterionic products such as 5. This dissociates to the ylide 4 so that carrying out the reaction in the presence of an aldehyde leads to a Wittig reaction to give 2-alkylidene-1,3-dithiolanes, The compound 5 reacts with acetylenic dipolarophiles by cycloaddition accompanied by loss of Bu(3)(II)P to give dihydro-TTF derivatives, Both these reaction types also occur for norbornadiene and by using this together with dialdehydes or diacetylenes a range of new sulfur-rich extended and polymeric structures have been obtained.