Ring Expansion versus exo−endo Isomerization in (2-Pyridyl)methylenecyclobutane Coordinated to Hydrido(trispyrazolyl)borate- and Cyclopentadienyl-Osmium Complexes

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• 作者：Ruth Castro-Rodrigo ; Miguel A. Esteruelas ; Ana M. Lpez ; Fernando Lpez ; Jos L. Mascareas ; Silvia Mozo ; Enrique Oate ; Luca Saya
• 刊名：Organometallics
• 出版年：2010
• 出版时间：May 24, 2010
• 年：2010
• 卷：29
• 期：10
• 页码：2372-2376
• 全文大小：758K
• 年卷期：v.29,no.10(May 24, 2010)
• ISSN：1520-6041

文摘

The reactions of (2-pyridyl)methylenecyclobutane with the metal fragments [OsTp(PⁱPr₃)]⁺ and [OsCp(PⁱPr₃)]⁺ (Tp = hydridotris(pyrazolyl)borate, Cp = cyclopentadienyl) are shown. Complex [OsTp(κ¹-OCMe₂)₂(PⁱPr₃)]BF₄ (1) reacts with the organic substrate to give [OsTp{η²-C(CH₂CH₂CH₂)═CH-C₅H₄N}(PⁱPr₃)]BF₄ (2), which evolves into the cyclopentylidene derivative [OsTp(═CCH₂CH₂CH₂CH-C₅H₄N)(PⁱPr₃)]BF₄ (3) as a result of the ring expansion of the methylenecyclobutane unit of the coordinated substrate. The reaction of (2-pyridyl)methylenecyclobutane with [OsCp(NCCH₃)₂(PⁱPr₃)]PF₆ (4) leads to [OsCp{η²-C(CH₂CH₂CH₂)═CH-C₅H₄N}(PⁱPr₃)]PF₆ (5). In contrast to 2, complex 5 evolves by means of exo−endo isomerization of the C−C double bond of the coordinated substrate to afford [OsCp{η²-C(═CHCH₂CH₂)-CH₂-C₅H₄N}(PⁱPr₃)]PF₆ (6).