Polysiloxane-bound ligand accelerated catalysis: a modular approach to heterogeneous and homogeneous macromolecular asymmetric dihydroxylation ligands
作者:Michael S. DeClue、Jay S. Siegel
DOI:10.1039/b406341d
日期:——
polysiloxane backbone while approximately half of these sites contained ligand in the homogeneous version. This approach led to macromolecular catalysts with high loadings of ligand and therefore materials with very low equivalent weights. Although these polymers are highly loaded they do maintain reactivity on a par with their free ligand counterpart. Using straightforward purification techniques (i.e. precipitation
Silicone-Supported Cinchona Alkaloid Derivatives as Insoluble Organocatalysts in the Enantioselective Dimerization of Ketenes
作者:Damiano Cancogni、Alessandro Mandoli、Ravindra P. Jumde、Dario Pini
DOI:10.1002/ejoc.201101320
日期:2012.3
ester and silyl ether derivatives of theCinchona alkaloid 10,11-dihydroquinidine within insoluble cross-linked silicone elastomeric films. These materials were effective heterogeneous organocatalysts in the asymmetric dimerization of ketenes, which provided chiral Weinreb β-ketoamides in 28–83 % yield and 79–99 % ee in the course of several recycles. A productivity/enantioselectivity protocol is also proposed
提出了一种简单的方法,用于将金鸡纳生物碱 10,11-二氢奎尼丁的酯和甲硅烷基醚衍生物共价固定在不溶性交联有机硅弹性体膜中。这些材料是烯酮不对称二聚中有效的多相有机催化剂,在几次循环过程中以 28-83% 的产率和 79-99% 的 ee 提供手性 Weinreb β-酮酰胺。还提出了生产力/对映选择性协议,以更好地评估可溶性和支持的不对称催化系统对过程强化的相对优点。