Permethyl Yttrocene 2-Furyl Complexes: Synthesis and Ring-Opening Reactions of the Furyl Moiety

Abstract

Permethyl yttrocene 2-furyl ate-complexes Cp*2Y(μ-C4H3O)(μ-Cl)Li(THF)2 (1, Cp* = C5Me5) and Cp*2Y(μ-C4H3O)2Li(TMEDA) (2) were obtained by reaction of Cp*2Y(μ-Cl)2Li(OEt2)2 with 1 and 2 equiv of 2-lithiofuran, respectively. Furan is metalated by (Cp*2YH)2 in hydrocarbon solvents to give the 2-furyl complex Cp*2Y(η2-C4H3O) (3). With Lewis bases, 3 reacts to give the adducts Cp*2Y(η1-C4H3O)(L) (L = THF, 4; pyridine), of which 4 was crystallographically characterized. Compound 3 decomposes through deprotonation and ring-opening of the 2-furyl group to give the (crystallographically characterized) bimetallic ynyl-enolate complex (Cp*2Y)2(μ-OCHCHC⋮C) (5). With excess H2, 3 is transformed into the crystallographically characterized oxo-complex (Cp*2Y)2(μ-O) (6), free furan, and n-butane. In the presence of a large excess of furan, this reaction stops at the enolate species Cp*2YOCHCHEt.