Unusual Regioselectivity in the Aldehyde Addition Reactions of Allenyl/Propargyl Zirconium Complexes Derived from 纬-(2-Pyridyl)propargyl Ethers: Synthesis of Multisubstituted 伪-Hydroxyallenes

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• 作者：Guoqin Fan ; Xin Xie ; Yuanhong Liu ; Yuxue Li
• 刊名：Organometallics
• 出版年：2013
• 出版时间：March 25, 2013
• 年：2013
• 卷：32
• 期：6
• 页码：1636-1642
• 全文大小：441K
• 年卷期：v.32,no.6(March 25, 2013)
• ISSN：1520-6041

文摘

Zirconium-mediated reactions of 纬-(2-pyridyl)propargyl ethers with aldehydes afford 伪-hydroxyallenes selectively via the formation of allenyl/propargyl zirconium species. The reaction outcome is quite different to that of the reactions using propargylic ethers without a pyridyl group reported so far, in which homopropargyl alcohols were formed predominantly. The structure of allenylzirconium intermediate has been confirmed by X-ray crystal analysis which reveals an intramolecular Zr鈥揘 coordination. DFT calculations suggest that the smaller steric effect of the pyridine ring compared with the phenyl ring and its capability to form hydrogen bondings with hydrogen atoms of the Cp ligand and the aldehyde may account for the observed regioselectivity.