轴向手性阻转异构化合物广泛用于不对称催化和药物化学中,对合成的有效方法有很高的要求。这尤其适用于衍生自五元芳族环的阻转异构体,因为它们在联芳基轴之间旋转的较低阻挡层限制了它们的不对称合成。我们在这里报告了一种手性Rh Jas Cp络合物的对映选择性CH功能化方法,用于合成可从三个不同的五元环杂环中获得的联芳基阻转异构体类型。
Organocatalytic Formal (3 + 2) Cycloaddition toward Chiral Pyrrolo[1,2-<i>a</i>]indoles via Dynamic Kinetic Resolution of Allene Intermediates
作者:Jian-Fei Bai、Lulu Zhao、Fang Wang、Fachao Yan、Taichi Kano、Keiji Maruoka、Yuehui Li
DOI:10.1021/acs.orglett.0c01812
日期:2020.7.17
straightforward method to synthesize chiral pyrrolo[1,2-a]indole bearing a tetrasubstituted carbon stereocenter. The reaction proceeds smoothly with a wide array of substrate tolerance to deliver various chiral pyrrolo[1,2-a]indoles in up to 93% yield and 98% ee. The utility of this method is highlighted by the diverse transformations of the products into various indolederivatives.
我们报道了手性磷酸催化的3-取代的1 H-吲哚和含有功能性导向基团(对-NHAc或对-OH)的炔丙醇的正式(3 + 2)环加成反应。这项工作代表了一种简单的方法来合成带有四取代碳立体中心的手性吡咯并[1,2- a ]吲哚。反应以多种底物耐受性顺利进行,以高达93%的收率和98%ee的产率递送各种手性吡咯并[1,2- a ]吲哚。通过将产物多样化转化为各种吲哚衍生物,突出了该方法的实用性。
Methylation of C(sp<sup>3</sup>)–H/C(sp<sup>2</sup>)–H Bonds with Methanol Catalyzed by Cobalt System
作者:Zhenghui Liu、Zhenzhen Yang、Xiaoxiao Yu、Hongye Zhang、Bo Yu、Yanfei Zhao、Zhimin Liu
DOI:10.1021/acs.orglett.7b02462
日期:2017.10.6
a commercially available Co salt, a tetradentate phosphine ligand P(CH2CH2PPh2)3(PP3), and a base (denoted as [Co]/PP3/base), is developed for the methylation of C(sp3)–H and C(sp2)-H bonds using methanol as a methylating reagent. The Co(BF4)2·6H2O/PP3/K2CO3 catalytic system showed high catalytic activity for the methylation of C–H bonds in aryl alkyl ketones, aryl acetonitriles, and indoles, with wide
一种高效的钴基催化体系,由市售的钴盐,四齿膦配体P(CH 2 CH 2 PPh 2)3(PP 3)和碱(表示为[Co] / PP 3 / base)组成),用于使用甲醇作为甲基化试剂对C(sp 3)–H和C(sp 2)-H键进行甲基化。Co(BF 4)2 ·6H 2 O / PP 3 / K 2 CO 3催化体系对芳烷基酮,芳基乙腈和吲哚中CH键的甲基化反应具有很高的催化活性,具有广泛的底物范围和良好的官能团耐受性,在100°C条件下获得的甲基取代产物的收率好至极好C。这种便宜,容易获得且高效的Co基催化体系在使用甲醇的甲基化反应中可能具有广阔的应用前景。
Asymmetric Synthesis of Furo[3,4‐
<i>b</i>
]indoles by Catalytic [3+2] Cycloaddition of Indoles with Epoxides
A highly efficient N,N′‐dioxide–NiII catalyst system for the catalytic [3+2] cycloaddition of indoles with epoxides through CC cleavage of oxiranes was accomplished under mild conditions. It provided a promising approach for chiral furo[3,4‐b]indoles in up to 98 % yield with up to 91 % enantiomeric excess (ee) and >95:5 diastereomeric ratio (d.r.).
一个高效Ñ,Ñ '二氧化物-镍II为吲哚与环氧化物至C催化的[3 + 2]环加成催化剂体系环氧乙烷的C ^裂解温和的条件下完成的。它为手性呋喃[3,4- b ]吲哚提供了一种有前途的方法,产率高达98%,对映体过量(ee)高达91%,非对映体比率(dr)大于95:5。
Enantioselective 2-Alkylation of 3-Substituted Indoles with Dual Chiral Lewis Acid/Hydrogen-Bond-Mediated Catalyst
作者:Zijun Zhou、Yanjun Li、Lei Gong、Eric Meggers
DOI:10.1021/acs.orglett.6b03500
日期:2017.1.6
hydrogen bond formation. This new bifunctional chiral Lewis acid/hydrogen-bond-mediated catalyst permits the challenging enantioselective 2-alkylation of 3-substituted indoles with α,β-unsaturated 2-acyl imidazoles in up to 99% yield and with up to 98% enantiomeric excess at a catalyst loading of 2 mol %. As an application, the straightforward synthesis of a chiral pyrrolo[1,2-a]indole is demonstrated.
手性金属双环金属化铱配合物将通过金属配位的亲电子活化与通过氢键形成的亲核活化结合在一起。这种新型的双功能手性路易斯酸/氢键介导的催化剂可实现具有α,β-不饱和2-酰基咪唑的3-取代吲哚的具有挑战性的对映选择性2-烷基化,产率最高可达99%,对映体过量可达98%。催化剂负载量为2摩尔%。作为一种应用,证明了手性吡咯并[1,2- a ]吲哚的直接合成。
Enantioselective Dearomatization of Indoles by an Azoalkene‐Enabled (3+2) Reaction: Access to Pyrroloindolines
作者:Guang‐Jian Mei、Xiwen Tang、Yildiz Tasdan、Yixin Lu
DOI:10.1002/anie.201911686
日期:2020.1.7
The enantioselectivedearomatization of indoles by an organocatalytic (3+2) reaction has been established. The reaction makes use of simple indole derivatives as substrates, and employs azoalkenesreaction partners. A wide range of pyrroloindolines containing an all-carbon quaternary stereogenic center were readily prepared in high yields and with excellent enantioselectivities.