A New Class of Modular P,N-Ligand Library for Asymmetric Pd-Catalyzed Allylic Substitution Reactions: A Study of the Key PdâÏ-Allyl Intermediates
作者:Javier Mazuela、Alexander Paptchikhine、Päivi Tolstoy、Oscar Pà mies、Montserrat Diéguez、Pherâ
G. Andersson
DOI:10.1002/chem.200901842
日期:2010.1.11
A new class of modular P,N‐ligand library has been synthesized and screened in the Pd‐catalyzed allylic substitution reactions of several substrate types. These series of ligands can be prepared efficiently from easily accessible hydroxyl–oxazole/thiazole derivatives. Their modular nature enables the bridge length, the substituents at the heterocyclic ring and in the alkyl backbone chain, the configuration
合成了新型的模块化P,N-配体库,并在几种底物类型的Pd催化的烯丙基取代反应中进行了筛选。这些系列的配体可以从容易获得的羟基-恶唑/噻唑衍生物中高效制备。它们的模块性质使桥的长度,杂环和烷基主链上的取代基,配体主链的构型以及亚磷酸亚芳基酯部分中的取代基/构型易于系统地变化。因此,通过仔细选择配体成分,可以实现较高的区域选择性和对映选择性(ee值高达96%),并在广泛的单取代,二取代和三取代的线性受阻和不受阻底物和环状底物中实现了良好的活性。对Pd-π-烯丙基中间体的NMR光谱和DFT研究提供了对配体参数对对映选择性起源的影响的更深刻的理解。