Reactions of Alkynyl−Ruthenium Complexes with the Ketene Dithioacetal, (MeS)₂CC(CN)₂

Reactions of several alkynyl−ruthenium complexes with the ketene dithioacetal (MeS)2CC(CN)2 (2) are described. The first examples of metalated 6-alkylthio-6-azafulvenes, Ru{CCRC(SMe)C(CN)CN(SMe)}(PPh3)Cp [R = Ph (5a), Fc (5b)], were obtained from Ru(CCR)(PPh3)2Cp, while Ru(CCPh)(CO)(PPh3)Cp gave dienyl complexes Ru{C(SMe)CPhC(SMe)C(CN)2}(CO)(PPh3)nCp [n = 1 (8), 0 (9)]. Yields of the azafulvenes were increased under conditions conducive to radical formation. The reaction between 5 and Ru(CCCCPh)(PPh3)2Cp afforded the alkynyl−dienyl Ru{C(SMe)C(CCPh)C(SMe)C(CN)2}(PPh3)Cp (11) and the dienynyl Ru{CCC(SMe)CPhC(SMe)C(CN)2}(PPh3)2Cp (12), formed by formal insertion of either CC triple bond into one C−S bond. The reaction of Ru(CCPh)(PPh3)2Cp with dimethyl 2,3-dicyanofumarate (3) afforded diastereomers of the η3-dienyl complex Ru{η3-C(CN)(CO2Me)CPhCC(CN)(CO2Me)}(PPh3)Cp (13). XRD structural determinations of 5a, 8, 9, 11, and one diastereomer of 13 are reported.