REACTIONS OF [RUCLH(CO)(BSD)(PPH3)2] (BSD = BENZO-2,1,3-SELENADIAZOLE) WITH ALKYNES

The reactions of [RuClH(CO)(BSD)(PPh3)2] (BSD = benzo-2,1,3-selenadiazole) with alkynes have been investigated and found to proceed readily with cis-hydroruthenation of the alkyne: The alkynes H-C = C-R (R = H, (n)C4H9, C6H4Me-4, CMe2OH) provide simple 18-electron sigma-E-vinyl complexes [Ru(CH = CHR)-Cl(CO)(BSD)(PPh3)2]; diphenylbutadiyne provides an alpha-(ethynyl)vinyl derivative [Ru{C(C = CPh) = CHPh}Cl(CO)(BSD)(PPh3)2], whilst the propargylic ylide precursor HC = C-CH2CH(CO2Et)PO(OEt)2 yields the novel complex [Ru(CH = CH-CH2CH(CO2Et)PO(OEt)2)Cl(CO)(BSD)(PPh3)2]. The BSD ligand in these complexes inhibits secondary insertion reactions but is sufficiently labile to be readily replaced by (2,6-dimethylphenyl)isonitrile to provide [Ru(vinyl)Cl(CO)(CNC6H3Me2-2,6)(PPh3)2].