Intramolecular Hydroalkylation as a Route to Strained Dicationic Bis(arene) [3]Ruthenocyclophanes

Abstract

Base-promoted intramolecular hydroalkylation of the carbon−carbon triple bond in the ruthenium bis(arene) complexes [(p-cymene)Ru(η 6-C6H5C⋮CR)][OTf]2 (1, R = Et; 2, R = Ph; OTf = O3SCF3) generates the strained [3]ruthenocyclophane complexes 3 and 4, in which a propenyl (−CH2CRCH−) group bridges the two arene ligands. The presence of the propenyl bridge results in a bent-metallocene structure for the [3]ruthenocyclophane cation in 4, with an angle of 11.8° between the arene ligands.

Preparation, Reactivity and Peptide Labelling Properties of (η6‐Arene)ruthenium(II) Complexes with Pendant Carboxylate Groups

“…The 1 H NMR signal for the benzyl protons of 4b can be observed at δ ϭ 3.67 ppm in acetonitrile (or CD 3 OH) but disappears within 5 min in D 2 O or CD 3 OD. The responsible rapid H/D exchange in the latter solvents is clearly a consequence of the relatively high acidity of the methylene protons in 4b as a result of both the η 6 -coordination of the phenyl group [25,26] and the presence of a neighbouring carboxylate group. A similar H/D exchange is also observed for 4a in CD 3 OD but not for the η 6 -phenylbutyric acid complex 5 with its longer side-chain.…”

Spirocyclic and Bicyclic Cyclohexadienyl Complexes from Intramolecular Nucleophilic Addition Reactions in Dicationic Arene Complexes

“…Research efforts in our laboratory have focused on exploiting the substantial electrophilic activation of the arene ligands in dicationic arene complexes of ruthenium and iridium for organic synthesis applications. , Several characteristics of these complexes make them attractive substrates for the continued development of intramolecular nucleophilic addition reactions. The ability of dicationic arene complexes to react with a wide range of nucleophiles , may dramatically expand the scope of this methodology by providing access to more types of spirocyclic and bicyclic ring systems.…”

Remarkably Favorable Hydration of Carbonyl Substituents in Dicationic Bis(arene) Ruthenium Complexes

“…Aromatic carbonyls are notoriously poor substrates for the direct formation of metal arene complexes. , We have found, however, that the direct metalation of benzaldehyde and acetophenone with [( p -cymene)Ru(OTf) 2 ] (OTf = O 3 SCF 3 ) proceeds in excellent yield (>85%) in nitromethane at 60 °C to give the corresponding bis(arene) ruthenium complexes, 1 and 2 (eq 1). , The use of CH 3 NO 2 as the solvent is absolutely crucial in these reactionsno formation of 1 is observed when other solvents (CH 2 Cl 2 , CF 3 CO 2 H) are employed . Both 1 and 2 have been completely characterized by spectroscopic methods; 1 was also characterized by X-ray crystallography (Figure ).…”