Selective transformations of alkynes with ruthenium catalysts

The electrophilic activation of terminal alkynes by suitable ruthenium(II) catalyst precursors has provided selective access to enol esters, functional dienes, ketoesters and furans. The step-by-step modification of the ligands of simple complexes such as (arene)RuCl 2 (PR 3 ), [Ru(µ-O 2 CH)(CO) 2 (PR 3 )] 2 or (diphosphine)Ru(allyl) 2 , has allowed the determination of efficient catalytic conditions for regio- and stereo-selective additions to alkynes. The utilization of electron-rich ruthenium(II) complexes containing the bulky pentamethylcyclopentadienyl ligand, has made possible the catalytic carbon–carbon bond forming reaction from alkynes and allyl alcohol to give unsaturated aldehydes.