Metathesis of Olefin-Substituted Pyridines: The Metalated NCN-Pincer Complex in a Dual Role as Protecting Group and Scaffold Part of this work was presented at the 14th International Symposium on Olefin Metathesis, Boston, August 2001
作者:Harm P. Dijkstra、Aleksey Chuchuryukin、Bart M. J. M. Suijkerbuijk、Gerard P. M. van Klink、Allison M. Mills、Anthony L. Spek、Gerard van Koten
DOI:10.1002/1615-4169(200208)344:6/7<771::aid-adsc771>3.0.co;2-c
日期:2002.8
diolefin-substituted pyridines (3,5- or 2,6-substitution) were successfully synthesized, and subsequently used in olefin meta- thesis (RCM) as a model study for template-directed synthesis of macrocycles. Especially a 3,5-disubstitut- ed pyridine bound to a NCN-Pt II -center (5a) gave a fast metathesis reaction, while the same reaction with the Pd II analogue (4a) was much slower and less selective (isomerization products
钳形钯 (II) 和 - 铂 (II) 阳离子,YCY-M (YCY (2,6-(YCH2)2C6H3) ;Y NMe2, SPh; M Pd II ,P t II ),与二烯烃结合-取代吡啶(3,5-或2,6-取代)被成功合成,随后用于烯烃复分解(RCM)作为模板指导合成大环化合物的模型研究。尤其是与 NCN-Pt II 中心 (5a) 结合的 3,5-二取代吡啶产生了快速的复分解反应,而与 Pd II 类似物 (4a) 的相同反应则慢得多且选择性较低(异构化产物为形成)。此外,发现 2,6-二烯烃取代的吡啶 (4b, 5b, 5c) 产生缓慢的复分解反应,这主要归因于闭环步骤中的空间位阻。在所有需要延长反应时间的异构化过程中,最有可能由阳离子钳-M II 物种辅助,被观察为竞争反应。1 HN MR 光谱实验表明,吡啶与阳离子 NCN-Pt II 中心的结合比与 Pd II 类似物的结合