BCSJ Award Article : C-F Bond Breaking through Aromatic Nucleophilic Substitution with a Hydroxo Ligand Mediated via Water Bifunctional Activation

DOI PDF Web Site 被引用文献6件 参考文献117件

この論文をさがす

抄録

<jats:title>Abstract</jats:title> <jats:p>Transformation of C–F to C–O bond mediated by bifunctional ruthenium and iridium complexes is described. This reaction proceeds through water O–H bond cleavage via metal–ligand cooperation in the newly developed 16e bifunctional ruthenium and iridium complexes bearing chiral (S,S)-C6F5SO2-dpen ligand. The 16e Ru amido complex, [Ru{(S,S)-Pfbsdpen}(η6-hmb)] (1a), readily reacted with water at room temperature producing oxometallacyclic compound, (R)-[Ru{κ3(N,N′,O)-(S,S)-OC6F4SO2dpen}(η6-hmb)] (3aR), as a result of bifunctional water activation followed by ortho-oxometallation via SNAr. Complex 3aR can be prepared either from 1a or, more conveniently from its 18e chlorido precursor, complex (R)-[RuCl{(S,S)-Pfbsdpen}(η6-hmb)]. On the contrary, the 16e Ir amido complex, [Cp*Ir{(S,S)-Pfbsdpen}] (2), is kinetically stable toward water at room temperature. Oxometallacyclic compound (R)-[Cp*Ir{κ3(N,N′,O)-(S,S)-OC6F4SO2dpen}] (4R) was prepared in high yield by the reaction of [Cp*IrCl2]2 with 2 equiv of (S,S)-Pfbsdpen in the presence of KOH under reflux in THF. In either case 3R or 4R is obtained as a single diastereomer, the structure of which has been determined by single-crystal X-ray diffraction studies in solid state and NMR-analysis in solution. Reaction mechanism was studied by NMR spectroscopy combined with continuum solvent reaction-field density functional theory (DFT) analysis. Experimental studies showed that diastereoselective oxocyclometallation 1a → 3aR proceeds at temperatures &gt;0 °C in a stepwise manner through the detectable intermediate, hydroxo complex (R)-[Ru(OH){(S,S)-Pfbsdpen}(η6-hmb)] (6aR), which exists in equilibrium with less-populated diastereomer (S)-[Ru(OH){(S,S)-Pfbsdpen}(η6-hmb)] (6aS) in 10:1 ratio at −80 °C in CD2Cl2. Computational analysis essentially explains the diastereoselectivity in this reaction via a significant difference in the stabilities of the corresponding transition states: although diastereomers 6aR and 6aS are in equilibrium via complex 1a, only 6aR is transformed into 3aR via rate-determining Meisenheimer-type transition state.</jats:p>

収録刊行物

被引用文献 (6)*注記

もっと見る

参考文献 (117)*注記

もっと見る

関連プロジェクト

もっと見る

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ