Unusually Accelerated Silylmethyl Transfer from Tin in Stille Coupling: Implication of Coordination-Driven Transmetalation
作者:Kenichiro Itami、Toshiyuki Kamei、Jun-ichi Yoshida
DOI:10.1021/ja0160593
日期:2001.9.1
accelerated by simply appending the 2-pyridyl group on silicon. The pyridyl-to-palladium coordination was validated in the palladium(II) complex 2-PyMe2SiCH2PdClPPh3 by 1H NMR and X-ray crystalstructure analysis. The cross-coupling product was used for further transformations. The C-Si oxidation of the cross-coupling product 2-PyMe2SiCH2Ar afforded ArCH2OH in high yield. The fluoride ion-catalyzed 1,2-addition
钯催化的 2-PyMe2SiCH2SnBu3 与芳基碘 (Ar-I) 的交叉偶联反应仅产生 2-PyMe2SiCH2 转移产物 2-PyMe2SiCH2Ar。发现有机基团从锡的相对转移能力为 2-PyMe2SiCH2 >> Ph > Me > Bu >> PhMe2SiCH2,这意味着有利的吡啶基-钯配位效应。因此,通过简单地将 2-吡啶基附加到硅上,可以显着加速甲硅烷基甲基从锡到钯的转移。通过 1H NMR 和 X 射线晶体结构分析,在钯 (II) 配合物 2-PyMe2SiCH2PdClPPh3 中验证了吡啶基与钯的配位。交叉偶联产物用于进一步转化。交叉偶联产物 2-PyMe2SiCH2Ar 的 C-Si 氧化以高产率提供了 ArCH2OH。氟离子催化1,