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首页> 外文期刊>Chemistry: A European journal >Application of a Supramolecular-Ligand Library for the Automated Searchfor Catalysts for the Asymmetric Hydrogenation of Industrially RelevantSubstrates
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Application of a Supramolecular-Ligand Library for the Automated Searchfor Catalysts for the Asymmetric Hydrogenation of Industrially RelevantSubstrates

机译：超分子配体库在工业相关底物不对称加氢自动搜索催化剂中的应用

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摘要

A procedure is described forthe automated screening and lead opti-mization of a supramolecular-ligand li-brary for the rhodium-catalyzed asym-metric hydrogenation of five challeng-ing substrates relevant to industry.Each catalyst is (self-) assembled fromtwo urea-functionalized ligands and atransition-metal center through hydro-gen-bonding interactions. The modularligand structure consists of three dis-tinctive fragments: the urea bindingmotif, the spacer, and the ligand back-bone, which carries the phosphorusdonor atom. The building blocks forthe ligand synthesis are widely avail-able on a commercial basis, thus ena- bling access to a large number of li-gands of high structural diversity. Thesimple synthetic steps enabled thescale-up of the ligand synthesis to mul-tigram quantities. For the catalystscreening, a library of twelve newchiral ligands was prepared that com-prised substantial variation in electron-ic and steric properties. The automatedprocedures employed ensured the fastcatalyst assembly, screening, and direct acquisition of samples for analysis. Itappeared that the most selective cata-lyst was different for every substrateinvestigated and that small variationsin the building blocks had a majorimpact on the catalyst performance.For two substrates, a catalyst wasfound that provided the product withoutstanding enantioselectivity. The sub-sequent automated optimization ofthese two leads showed that an in-crease of catalyst loading, dihydrogenpressure, and temperature had a posi-tive effect on the catalyst activity with-out affecting the catalyst selectivity.
机译：描述了一种程序的自动化筛选和优化铅的超分子配体库，用于铑催化的与工业相关的五种挑战性底物的不对称加氢反应。每种催化剂都是（自）由两种尿素组装而成的。通过氢键相互作用实现功能化的配体和过渡金属中心。模块化配体结构由三个不同的片段组成：尿素结合基，间隔基和带有磷供体原子的配体骨架。配体合成的基本组成部分可以在商业上广泛使用，因此可以使用大量具有高度结构多样性的配体。简单的合成步骤可将配体合成扩大到多种数量。为了筛选催化剂，制备了包含十二种新手性配体的库，该库包括电子性质和空间性质的显着变化。所采用的自动化程序确保了快速催化剂的组装，筛选和直接采集样品进行分析。似乎对于每种被研究的底物来说，最有选择性的催化剂是不同的，并且结构单元的微小变化对催化剂的性能有重大影响。对于两种底物，发现了一种提供对映体选择性而没有产物的催化剂。随后对这两个线索进行的自动优化表明，增加催化剂负载量，双氢压力和温度对催化剂活性具有积极影响，而不会影响催化剂的选择性。

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