作者:Mukesh Kumar、Pankaj Chauhan、Stephen J. Bailey、Ehsan Jafari、Carolina von Essen、Kari Rissanen、Dieter Enders
DOI:10.1021/acs.orglett.8b00175
日期:2018.2.16
An efficient and highly stereoselective one-pot, four-component synthesis of functionalized tricyclic chromanes has been achieved through an organocatalyzed quadruple dominoreaction. The reaction sequence involves an oxa-Michael/Michael/Michael/aldol condensation between alcohols, 2 equiv of acrolein, and nitrochromenes to generate the pharmaceutically important tricyclic chromanes bearing three contiguous
通过有机催化的四重多米诺反应,已实现了高效且高度立体选择性的一锅四组分官能化三环苯并吡喃的合成。反应顺序包括在醇,2当量的丙烯醛和硝基色酮之间进行oxa-Michael / Michael / Michael / aldol缩合反应,以产生药学上重要的三环苯并三环苯并烷,其中包括三个连续的立体异构中心,包括手性四取代碳中心,具有良好的多米诺产量(30– 70%)和出色的非对映选择性和对映选择性(> 20:1 dr和> 99%ee)。
Enantioselective Cascade Michael Addition/Cyclization Reactions of 3-Nitro-2<i>H</i>-Chromenes with 3-Isothiocyanato Oxindoles: Efficient Synthesis of Functionalized Polycyclic Spirooxindoles
An unprecedented Zn(OTf)2‐catalyzed asymmetric Michaeladdition/cyclization cascade of 3‐nitro‐2H‐chromenes with 3‐isothiocyanato oxindoles has been disclosed. This transformation provides an efficient access to various synthetically important polycyclic spirooxindoles in a highly stereoselective manner under mild conditions (72–99 % yields, up to >95:5 d.r. and >99 % ee). The reaction leads to the
公开了前所未有的Zn(OTf)2催化的3-硝基-2 H-色酮与3-异硫氰酸根合吲哚的不对称Michael加成/环化级联反应。这种转化可在温和条件下(72–99%的收率,高达> 95:5 dr和> 99%ee的情况下)以高度立体选择性的方式,有效地获得各种合成上重要的多环螺氧并吲哚类化合物 。该反应可在一次操作中形成三个连续的立体中心,包括1,3-不相邻的四取代碳立体中心。基于对照实验,提出了手性Zn(OTf)2 /双(恶唑啉)配合物的双功能激活模型,其中Zn II 分子部分起路易斯酸的作用,而游离NH基团的N原子通过氢键相互作用起路易斯碱的作用。
Enantioselective [4+2] Cycloadditions of 2-Vinyl-1 H-indoles with 3-Nitro-2 H-chromenes Catalyzed by a Zn(OTf)2/Bis(oxazoline) Complex: An Efficient Approach to Fused Heterocycles with a Quaternary Stereocenter
There's a ringer: The asymmetric [4+2] cycloaddition reaction of 3‐nitro‐2H‐chromenes with 1‐benzyl‐2‐vinyl‐1H‐indoles catalyzed by Zn(OTf)2 with bis(oxazoline) ligands offers a practical and efficient method to synthesize a variety of fused heterocycles bearing a quaternary stereocenter with good reaction efficiency (up to 94% yield) and excellent stereoselectivities (up to 96% ee, >95:5 d.r.).
A highly stereoselective triple dominoreaction for the synthesis of functionalized tricyclic chromane scaffolds has been developed. A secondary amine-catalyzed domino Michael/Michael/aldol condensation reaction between aliphatic aldehydes, nitro-chromenes, and α,β-unsaturated aldehydes leads to the formation of synthetically important tricyclic chromanes bearing four contiguous stereogenic centers
已经开发出用于合成官能化的三环苯并二氢吡喃骨架的高度立体选择性的三重多米诺反应。脂族醛,硝基色烯和α,β-不饱和醛之间的仲胺催化的多米诺Michael / Michael / aldol缩合反应导致形成重要的具有三个连续立体中心的合成重要的三环苯并二氢吡喃中心,包括收率高的四取代碳( 20–66%)和出色的立体选择性(> 20:1 dr和> 99%ee)。