Oligomerisation of alkynes at a pentamethylcyclopentadienylruthenium centre

摘要

Reactions between the neutral vinylidene RuCl(=C=CHPh)(PPh3)Cp* 2 and AgC=CCO2Me gave Ru{eta(1)-C(C=CPh)=CHC(O)OMe-O}(PPh3)Cp* 3, while either LiC=CPh or HC=CPh/NaOMe afforded the known Ru{eta(3)-PhCHCHC=CPh(C=CPh)}(PPh3)Cp* 1. Similarly, RuCl{=C=CH(CO2Me)}(PPh3)Cp* 4 reacted with HC=CPh/NaOMe to give Ru{eta(3)-CH(CO2Me)CHC=CPh(C=CCO2Me)}(PPh3)Cp* 5. Complex 3 reacted with HC=CCO2R (R = Me or Et) to give the 1,3,4,5-tetraen-1-yls Ru{eta(1),eta(2)-C(CO2R)=CHCPh=C=C=CH(CO2Me)}(PPh3)Cp* (R = Me 6 or Et 7)] and with HC=CSiMe3 to give a mixture of Ru{eta(3)-CH(CO2Me)C(CH=CHSiMe3)C=CPhC=CSiMe3}(PPh3)Cp* 8 and Ru{eta(3)-CH(CO2Me)CHC=CPh(C=CSiMe3)}(PPh3)Cp* 9. Crystal structures of 1, 3 and 5-8 were determined. These reactions provide routes to the stepwise formation of novel non-cyclic oligomers of 1-alkynes, with 8 containing the first example derived from four alkynes. [References: 23]