Reactions of alkynyl-ruthenium complexes with the ketene dithioacetal, (MeS)₂C═C(CN)₂

Abstract

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. © 2008 American Chemical Society.