Reactivity of Alkali Metal Yldiides Toward Carbon Disulfide

The use of carbon disulfide as CS source for the construction of sulfur-containing molecules is an attractive strategy in organic synthesis. Herein, we report the formation of CS2 adducts with α-metalated ylides. The resulting alkali metal salts are readily isolable and were characterized by both spectroscopic and crystallographic methods. In the solid state, the CS2 complexes exhibit short, newly formed C–C bond distances, indicative of pronounced doublebond character and a strong contribution of the 1,1-dithiolate form. Investigations into the potential formation of alkynyl sulfide anions from the yldiide–CS2 complexes via phosphine sulfide release revealed reactivity patterns highly dependent on the ylide substituents. Thermal treatment of these complexes results either in phosphine sulfide elimination via C–P bond cleavage and presumed alkynyl sulfide formation or in C–Z bond scission with concomitant release of phosphoranylidene thioketene (Ph3P=C=C=S). Photolysis experiments indicate a preference for C–Z bond cleavage, albeit no approach delivered isolable products.