Regio- and diastereoselective nucleophilic additions of lithium enolates on the allenylidene complexes [Ru{= C = C = C(R)Ph}(eta(5)-C9H7)(PPh3)2][PF6] (R = H, Ph): Synthesis of the first chiral keto-functionalized (sigma-alkynyl)ruthenium(II) complexes

Indenylruthenium(II) allenylidene complexes undergo regioselective nucleophilic additions of lithium enolates at the C-gamma atom of the unsaturated chain to afford keto-functionalized sigma-alkynyl derivatives. Enolates derived from the chiral ketones: (-)-carvone and (+)-pulegone are added regio- and diastereoselectively to give the first chiral keto-functionalized (sigma-alkynyl)ruthenium(II) complexes.