Enzymatic resolution of hindered secondary alcohols: Efficient access to a new simplified chiral auxiliary
摘要:
2,2-Diphenylcyclopentanol, an efficient chiral auxiliary which bears only one stereogenic center, as well as some related hindered secondary alcohols, were resolved by means of pig liver acetone powder (PLAP) and horse liver acetone powder (HLAP).
Chiral-at-metal iridium complex for efficient enantioselective transfer hydrogenation of ketones
作者:Cheng Tian、Lei Gong、Eric Meggers
DOI:10.1039/c6cc00972g
日期:——
A bis-cyclometalated iridium(III) complex with metal-centered chirality catalyzes the enantioselectivetransferhydrogenation of ketones with high enantioselectivities at low catalyst loadings down to 0.002 mol%. Importantly, the rate of catalysis...
Using water as solvent, the oxidativekineticresolution of a wide range of racemicsecondaryalcohols with a chiral PNNP/Ir catalyst was investigated. The catalytic reaction proceeded smoothly with excellent enantioselectivity (up to 97% ee) under mild conditions, providing an environmentally benign process to achieve optically active alcohols.
使用 水 作为 溶剂,广泛的外消旋体的氧化动力学拆分 仲醇 带有手性PNNP / Ir 催化剂被调查了。催化反应在温和条件下以优异的对映选择性(高达97%ee)顺利进行,为实现光学活性提供了环境友好的工艺酒类。
Mechanism-Based Enantiodivergence in Manganese Reduction Catalysis: A Chiral Pincer Complex for the Highly Enantioselective Hydroboration of Ketones
作者:Vladislav Vasilenko、Clemens K. Blasius、Hubert Wadepohl、Lutz H. Gade
DOI:10.1002/anie.201704184
日期:2017.7.10
A manganese alkyl complex containing a chiralbis(oxazolinyl‐methylidene)isoindoline pincer ligand is a precatalyst for a catalytic system of unprecedented activity and selectivity in the enantioselective hydroboration of ketones, thus producing preparatively useful chiral alcohols in excellent yields with up to greater than 99 % ee. It is applicable for both aryl alkyl and dialkyl ketone reduction
含有手性双(恶唑啉基-亚甲基)异二氢吲哚钳位配体的锰烷基络合物是酮对映选择性氢硼化反应中空前的活性和选择性的催化体系的预催化剂,从而以高达99的高收率生产了制备有用的手性醇。 %ee。它适用于在温和的反应条件下(TOF> 450 h -1在-40°C下)。富含地球的贱金属催化剂在极低的催化剂负载量(低至0.1 mol%)下运行,并且具有很高的官能团耐受性。有证据表明存在两种不同的锰催化氢化物转移机理,并介绍了它们在选择性确定步骤中对映体控制的作用。
Manganese Catalyzed Asymmetric Transfer Hydrogenation of Ketones Using Chiral Oxamide Ligands
The asymmetric transferhydrogenation of ketones using isopropyl alcohol (IPA) as hydrogen donor in the presence of novel manganese catalysts is explored. The selective and active systems are easily generated in situ from [MnBr(CO)5] and inexpensive C 2-symmeric bisoxalamide ligands. Under the optimized reaction conditions, the Mn-derived catalyst gave higher enantioselectivity compared with the related
探索了在新型锰催化剂存在下使用异丙醇 (IPA) 作为氢供体的酮的不对称转移氢化。选择性和活性系统很容易由 [MnBr(CO)5] 和廉价的 C 2 对称双草酰胺配体原位生成。在优化的反应条件下,Mn 衍生的催化剂与相关的钌催化剂相比具有更高的对映选择性。
Iron Catalyzed Asymmetric Hydrogenation of Ketones
preferentially catalytically. Among all the asymmetric catalytic reactions, asymmetrichydrogenation with H2 (AH) is the most widely used in the industry. With few exceptions, these AH processes usecatalysts based on the three critical metals, rhodium, ruthenium, and iridium. Herein we describe a simple, industrially viable iron catalyst that allows for the AH of ketones, a process currently dominated by ruthenium
手性分子(如醇)对于精细化学品、药物、农用化学品、香料和新型材料的制造至关重要。这些分子需要以高产率和高光学纯度并优先催化生产。在所有的不对称催化反应中,工业上应用最广泛的是与H2(AH)的不对称加氢反应。除了少数例外,这些 AH 工艺使用基于三种关键金属(铑、钌和铱)的催化剂。在本文中,我们描述了一种简单的、工业上可行的铁催化剂,它允许酮的 AH,目前该过程主要由钌和铑催化剂主导。通过将手性 22 元大环配体与廉价、易得的 Fe3(CO)12 结合,多种酮在 50 bar H2 和 45-65 °C 下氢化,提供了非常有价值的手性醇,其对映选择性接近或超过用贵金属催化剂获得的那些。与大多数贵金属催化剂的 AH 相比,铁催化的氢化似乎是非均相的。