Asymmetric synthesis of cyclic β-amino acids and cyclic amines via sequential diastereoselective conjugate addition and ring closing metathesis
作者:Ann M Chippindale、Stephen G Davies、Keiji Iwamoto、Richard M Parkin、Christian A.P Smethurst、Andrew D Smith、Humberto Rodriguez-Solla
DOI:10.1016/s0040-4020(03)00411-3
日期:2003.4
β-unsaturated esters followed by ringclosingmetathesis is used to afford efficiently a range of substituted cyclic β-amino esters in high d.e. Alternatively, conjugate addition to α,β-unsaturated Weinreb amides, functional group conversion and ringclosingmetathesis affords cyclic amines in high d.e. The further application of this methodology to the synthesis of a range of carbocyclic β-amino esters via
Tandem olefin metathesis–elimination reactions. A new route to doubly unsaturated carbonyl derivatives
作者:Bruce H. Lipshutz、Subir Ghorai、Žarko V. Bošković
DOI:10.1016/j.tet.2008.04.027
日期:2008.7
Cross-metathesis between an activated olefin and an ethereal derivative of homoallylic alcohols leads to products that are subject to facile elimination resulting in α,β,γ,δ-unsaturated esters, ketones, acids, and aldehydes in high yields.
Synthesis of Linear (<i>Z</i>
)-α,β-Unsaturated Esters by Catalytic Cross-Metathesis. The Influence of Acetonitrile
作者:Elsie C. Yu、Brett M. Johnson、Erik M. Townsend、Richard R. Schrock、Amir H. Hoveyda
DOI:10.1002/anie.201608087
日期:2016.10.10
Kinetically controlled catalytic cross‐metathesis reactions that generate (Z)‐α,β‐unsaturated esters selectively are disclosed. A key finding is that the presence of acetonitrile obviates the need for using excess amounts of a more valuable terminal alkene substrates. On the basis of X‐ray structure and spectroscopic investigations a rationale for the positive impact of acetonitrile is provided. Transformations
High-value alcohols and higher-oxidation-state compounds by catalytic Z-selective cross-metathesis
作者:Ming Joo Koh、R. Kashif M. Khan、Sebastian Torker、Miao Yu、Malte S. Mikus、Amir H. Hoveyda
DOI:10.1038/nature14061
日期:2015.1
high-value compounds by cross-metathesis. The ruthenium complex is prepared from a commercially available precursor and an easily generated air-stable zinc catechothiolate. Transformations typically proceed with 5.0 mole per cent of the complex and an inexpensive reaction partner in 4–8 hours under ambient conditions; products are obtained in up to 80 per cent yield and 98:2 Z:E diastereoselectivity.
烯烃复分解催化剂为生命科学领域的医生和研究人员提供了必不可少的分子。然而,一个持续存在的问题是缺乏直接生成无环 Z 烯丙醇的化学转化,包括含有受阻相邻取代基或反应性功能单元(如苯酚、醛或羧酸)的产品。在这里,我们提出了一种电子改性的二硫化钌催化剂,它可以通过交叉复分解有效地产生这种高价值的化合物。钌配合物由市售前体和易于生成的空气稳定儿茶酚硫醇锌制备。在环境条件下,转化通常在 4-8 小时内以 5.0 摩尔百分比的配合物和廉价的反应伙伴进行;以高达 80% 的产率和 98:2 Z:E 非对映选择性获得产品。该催化剂的使用已在天然抗肿瘤剂 Neopeltolide 的合成以及可再生原料(油酸)向抗真菌剂的一步立体选择性克级转化中得到证明。在这种转化中,新催化剂比常用的二氯钌配合物更有效地促进交叉复分解,表明其效用可能超出 Z 选择性过程。
Palladium-Catalyzed Cascade sp<sup>2</sup>
C−H Functionalization/Intramolecular Asymmetric Allylation: From Aryl Ureas and 1,3-Dienes to Chiral Indolines
作者:Shu-Sen Chen、Min-Song Wu、Zhi-Yong Han
DOI:10.1002/anie.201702745
日期:2017.6.1
functionalization/intramolecular asymmetric allylation reaction is reported. A new chiral sulfoxide–oxazoline (SOX) ligand bearing single chiral center on the sulfur was identified as the optimal ligand for the reaction, being efficient both in the C−H cleavage step and the stereocontrol of the allylation step. The broad scope of this method with respect to aryl ureas and 1,3-dienes enables the rapid construction
报道了手性Pd II催化的级联sp 2 C H功能/分子内不对称烯丙基化反应。一种新的手性亚砜-恶唑啉(SOX)配体在硫上具有一个手性中心,被确定为该反应的最佳配体,在CH裂解步骤和烯丙基化步骤的立体控制方面均十分有效。关于芳基脲和1,3-二烯,该方法的广泛范围使得能够快速构建有价值的手性二氢吲哚衍生物,具有高收率和对映选择性(最高收率99%,最高收率95:5 er)。