Computationally Guided Design of a Readily Assembled Phosphite–Thioether Ligand for a Broad Range of Pd-Catalyzed Asymmetric Allylic Substitutions
作者:Maria Biosca、Jèssica Margalef、Xisco Caldentey、Maria Besora、Carles Rodríguez-Escrich、Joan Saltó、Xacobe C. Cambeiro、Feliu Maseras、Oscar Pàmies、Montserrat Diéguez、Miquel A. Pericàs
DOI:10.1021/acscatal.7b04192
日期:2018.4.6
A modular approach employing indene as common starting material, has enabled the straightforward preparation in three reaction steps of P-thioether ligands for the Pd-catalyzed asymmetric allylic substitution. The analysis of a starting library of P-thioether ligands based on rational design and theoretical calculations has led to the discovery of an optimized anthracenethiol derivative with excellent
A New Modular Phosphite-Pyridine Ligand Library for Asymmetric Pd-Catalyzed Allylic Substitution Reactions: A Study of the Key Pd-π-Allyl Intermediates
作者:Javier Mazuela、Oscar Pàmies、Montserrat Diéguez
DOI:10.1002/chem.201203365
日期:2013.2.11
A library of phosphite‐pyridine ligands L1–L12 a–g has been successfully applied for the first time in the Pd‐catalyzedallylicsubstitution reactions of several di‐ and trisubstituted substrates by using a wide range of C, N and O nucleophiles, among which are the little studied α‐substituted malonates, β‐diketones, and alkyl alcohols. The highly modular nature of this ligand library enables the
亚磷酸吡啶配体L1 – L12 a – g的文库通过使用广泛的C,N和O亲核试剂,已成功地将其首次成功地用于Pd催化的几种二和三取代底物的烯丙基取代反应中,其中包括研究较少的α-取代的丙二酸酯,β-二酮和烷基醇。该配体库的高度模块化性质使得配体主链上的取代基/构型以及亚磷酸亚芳基酯部分上的取代基/构型易于系统地变化。我们发现,对映体纯亚磷酸亚芳基酯部分的引入在增加Pd催化系统的多功能性方面起着至关重要的作用。因此,通过使用广泛的C,N和O亲核试剂,对几种受阻和不受阻的二取代和三取代底物的对映选择性很高。 ee)和三取代底物S6和S7获得的高活性,这与文献中报道的最佳活性相比是有利的。我们还扩大了这些新催化系统在替代性环境友好型溶剂(如碳酸亚丙酯和离子液体)中的使用。对Pd-π-烯丙基中间体的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。
Theoretical and Experimental Optimization of a New Amino Phosphite Ligand Library for Asymmetric Palladium-Catalyzed Allylic Substitution
A new library of modular amino phosphite ligands obtained in a few synthetic steps from enantiopure amino alcohols has been tested in asymmetric Pd‐catalyzed allylicsubstitution. The modular ligand design is crucial to find highly selective catalysts for each substrate type using a wide range of C‐, N‐, and O‐nucleophiles. A DFT study of the species responsible for the enantiocontrol was used to optimize
be efficiently introduced, independently of their nature. Among the whole library, ligands that contain an additional chiral centre in the alkyl backbone chain next to the phosphitegroup and an enantiopure biaryl phosphitegroup provided the best enantioselectivities. In general, there is a cooperative effect between these two chiral elements, and therefore, a matched combination between them is necessary
Ruthenium(ii)-catalysed cycloisomerisation of 1,6-dienes by focused microwave dielectric heating: improved rates and selectivities leading to exo-methylenecyclopentanes
作者:Ian J. S. Fairlamb、Gerard P. McGlacken、Felix Weissberger
DOI:10.1039/b513798e
日期:——
We herein report the effect of microwave dielectric heating in the Ru-catalysed cycloisomerisation of 1,6-dienes. Substantially improved reaction rates are attained for a series of 1,6-diene substrates, with equivalent or higher isomeric purity than conventional thermal heating.