Synthesis of lanthanide(II)–imine complexes and their use in carbon–carbon and carbon–nitrogen unsaturated bond transformation
作者:Ken Takaki、Kimihiro Komeyama、Katsuomi Takehira
DOI:10.1016/j.tet.2003.06.003
日期:2003.12
1 quantitatively, the structure of which was characterized by X-ray analysis. The imine complexes 1 catalyzed dehydrogenativesilylation of terminal alkynes, hydrosilylation of imines and alkenes, and intermolecular hydrophosphination of alkynes. Moreover, dehydrogenative double silylation of conjugated dienes was achieved with 1.
Alkyl Grignard reagents were found to be isomerized to more stable ones in high isomerization ratios (>99%) under cooperative catalysis by iron and copper, which promote isomerization of alkyl groups and transmetalation between Fe-Mg, respectively.
NiCl2·6H2O/tBuOK, for the electrophilically activated hydrosilylation of terminal alkenes with primary silanes. This protocol provides excellent performance under mild reaction conditions: exclusive anti-Markovnikov selectivity, broad functional group tolerance (36 examples), and good scalability (TON = 5500). However, the secondary and tertiarysilanes are not suitable. Mechanistic studies revealed that
我们报告了一种简单有效的镍基催化体系NiCl 2 ·6H 2 O / t BuOK,用于末端烯烃与伯硅烷的亲电子活化氢化硅烷化。该方案在温和的反应条件下具有出色的性能:独特的抗马尔科夫尼科夫选择性,宽泛的官能团耐受性(36个示例)和良好的可扩展性(TON = 5500)。但是,仲和叔硅烷是不合适的。机理研究表明,这种均相催化的硅氢加成反应包括一种亲电子活化的Si-H键过程,而不会产生氢化镍。
Hydrosilylation of olefins and dehydrogenative double silylation of conjugated dienes catalyzed by lanthanide–imine complexes
Divalent lanthanide–imine complexes and a related species catalyzed the hydrosilylation of olefins with phenyl- and diphenylsilane. On the other hand, conjugated dienes were converted to 1,4-bissilyl-2-butenes and 3-silacyclopentenes, accompanied with hydrogen evolution, under similar conditions.
Rare earth alkyl and hydride complexes bearing silylene-linked cyclopentadienyl-phosphido ligands. Synthesis, structures, and catalysis in olefin hydrosilylation and ethylene polymerization
作者:Olivier Tardif、Masayoshi Nishiura、Zhaomin Hou
DOI:10.1016/j.tet.2003.07.015
日期:2003.12
cyclopentadienyl-phosphido rareearthalkyl and hydride complexes of type Me2Si(C5Me4)(PR′)LnR (Ln=Y, Yb, Lu; R′=Ph, Cy, C6H2tBu3-2,4,6; R=CH2SiMe3, H) have been synthesized and structurally characterized, and their activity in ethylene polymerization and olefin hydrosilylation has been studied. These complexes represent the first examples of rareearthalkyl and hydride complexesbearing cyclopentadienyl-phosphido
Me 2 Si(C 5 Me 4)(PR')LnR(Ln = Y,Yb,Lu; R'= Ph,Cy,C 6 H合成了2 t Bu 3 -2,4,6; R = CH 2 SiMe 3,H)并对其结构进行了表征,并研究了它们在乙烯聚合和烯烃氢化硅烷化中的活性。这些配合物代表了带有环戊二烯基-磷基配体的稀土烷基和氢化物配合物的第一个例子,它们在结构和化学上都与类似的环戊二烯基-酰胺基和茂金属配合物形成鲜明对比。