Sweets for Catalysis - Facile Optimisation of Carbohydrate-Based Bis(oxazoline) Ligands
作者:Tobias Minuth、Mustafa Irmak、Annika Groschner、Tobias Lehnert、Mike M. K. Boysen
DOI:10.1002/ejoc.200801035
日期:2009.3
A new type of carbohydrate-based bis(oxazoline) ligands was prepared from inexpensive D-glucosamine and tested in asymmetric cyclopropanation reactions. For optimisation, modified ligands with 3-O substituents of varying size and electronic properties were prepared as well as a 3-OH unprotected and a perpivaloylated derivative. All new ligands were tested in asymmetric cyclopropanation, revealing a
一种新型的基于碳水化合物的双(恶唑啉)配体由廉价的 D-葡糖胺制备,并在不对称环丙烷化反应中进行了测试。为了优化,制备了具有不同大小和电子特性的 3-O 取代基的修饰配体以及未保护的 3-OH 和全新戊酰化衍生物。所有新配体都在不对称环丙烷化中进行了测试,揭示了对映选择性对 3-O 残基的空间需求和电子特性的强烈依赖性。此外,观察到由环状缩醛基团的存在或不存在决定的吡喃糖构象的显着影响。因此,很容易将新的碳水化合物双(恶唑啉)配体调整到给定的反应。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)