2-(Triphenylphosphonio)-4,5-bis(benzoylthio)-1,3-dithiole Tetrafluoroborate: A Versatile Wittig Reagent for the Synthesis of Unsymmetrical Tetrathiafulvalenes and 1,3-Dithiol-2-ylidene Derivatives

Article abstract of DOI:10.1021/jo00097a038

The title Wittig reagent 5 has been prepared in three steps (84percent overall yield) from 4,5-bis(benzoylthio)-1,3-dithiole-2-thione.Reactions of ylide 7, generated by treatment of 5 with diisopropylethylamine at room temperature, have been exploited in the synthesis of new unsymmetrical tetrathiafulvalenes and 1,3-dithiol-2-ylidene derivatives.Subsequent removal of the benzoyl protecting group with sodium ethoxide liberates the transient TTF-dithiolate or 1,3-dithiole-dithiolate anions which can be alkylated in situ.The X-ray crystal structures of compounds 17 and 18 are reported: close nonbonded S...O intramolecular interactions are observed in both structures.