Biferrocene-Based Diphosphine Ligands: Synthesis and Application of Walphos Analogues in Asymmetric Hydrogenations
作者:Afrooz Zirakzadeh、Manuela A. Groß、Yaping Wang、Kurt Mereiter、Felix Spindler、Walter Weissensteiner
DOI:10.1021/om3012147
日期:2013.2.25
A total of four biferrocene-based Walphos-type ligands have been synthesized, structurally characterized, and tested in the rhodium-, ruthenium- and iridium-catalyzed hydrogenation of alkenes and ketones. Negishi coupling conditions allowed the biferrocene backbone of these diphosphine ligands to be built up diastereoselectively from the two nonidentical and nonracemic ferrocene fragments (R)-1-(N
总共合成了四种基于双二茂铁的Walphos型配体,并在铑,钌和铱催化的烯烃和酮的氢化反应中进行了结构表征和测试。Negishi偶联条件允许从两个不相同和不外消旋的二茂铁片段(R)-1-(N,N-二甲基氨基)乙基二茂铁和(S Fc)-2-bromoiodoferrocene选择性非对映地建立这些二膦配体的二茂铁骨架。(S Fc)-2-溴碘二茂铁的分子结构,偶联产物,两个配体和两个配合物([PdCl2(L)]和[RuCl(p-cymene)(L)] PF6)的结构由X-射线衍射。将配合物的结构特征和使用新合成的基于二茂铁的配体获得的催化结果与相应的Walphos配体进行了比较。