Combining Electronic and Steric Effects To Generate Hindered Propargylic Alcohols in High Enantiomeric Excess
作者:Vijyesh K. Vyas、Richard C. Knighton、Bhalchandra M. Bhanage、Martin Wills
DOI:10.1021/acs.orglett.7b03884
日期:2018.2.16
o-fluoro substituents results in an improvement to the reduction enantioselectivity, as does the replacement of a phenyl ring on the alkyne with a trimethylsilyl group. These effects are rationalized as resulting from a change in the steric properties of the aryl ring and the electronic properties of the alkyne which, when matched in the reduction transition state, combine within a “window” of substrate/catalyst
A novel copper-catalyzed tandemreaction of 1-(2-iodoaryl)-2-yn-1-ones with isocyanides is described. The reaction is through a formal [3 + 2] cycloaddition/coupling tandem process and leads to efficient formation of 4-oxo-indeno[1,2-b]pyrroles.
描述了一种新型的铜催化的1-(2-碘芳基)-2-yn-1-one与异氰酸酯的串联反应。该反应通过正式的[3 + 2]环加成/偶联串联过程进行,并导致4-氧代茚并[1,2- b ]吡咯的有效形成。
Selective Insertion of Alkynes into C–C σ Bonds of Indolin-2-ones: Transition-Metal-Free Ring Expansion Reactions to Seven-Membered-Ring Benzolactams or Chromone Derivatives
作者:Mengdan Wang、Yajie Yang、Bo Song、Liqiang Yin、Shuhui Yan、Yanzhong Li
DOI:10.1021/acs.orglett.9b04081
日期:2020.1.3
An unprecedented ring expansion reaction of indolin-2-ones with alkynyl ketones under transition-metal-free conditions has been developed. Base-promoted selective cleavage of a C-Cσbond of the amide is the key in this process, which provides a straightforward and efficient way to synthesize seven-membered-ring benzolactams or chromone derivatives. The significant advantages of this method include
<i>N</i>-Iodosuccinimide-Promoted Rapid Access to Indeno[1,2-<i>c</i>]pyrroles<i>via</i>[3+2] Annulation of Enamine-alkynes
作者:Jampani Santhi、Beeraiah Baire
DOI:10.1002/adsc.201600711
日期:2016.12.7
(NIS)‐promoted, cascade strategy for the efficient synthesis of biologically important indeno[1,2‐c]pyrroles via a [3+2] annulation process of enamine‐alkynes. This methodology had shown a very broad scope for diversely functionalized enamines and alkynes. We have also developed a one‐pot, multicomponent strategy for the direct synthesis of indeno‐pyrrolesfrom diynones via enamine‐alkynes. Control experiments
我们已经开发了一种无金属,N-碘代琥珀酰亚胺(NIS)促进的级联策略,用于通过烯胺炔烃的[3 + 2]环合法有效合成重要的生物学上重要的茚并[1,2- c ]吡咯。该方法学显示了功能多样的烯胺和炔烃的广泛应用范围。我们还开发了一种单锅多组分策略,可通过烯胺炔烃直接从二酮中合成茚并吡咯。对照实验支持NIS通过离子机制而非自由基途径作为亲电子活化剂的参与。
Synthesis of 1,4-benzoxazines <i>via</i> Y(OTf)<sub>3</sub>-catalyzed ring opening/annulation cascade reaction of benzoxazoles with propargylic alcohols
作者:Hongbo Qi、Yupeng Zhao、Wencong Li、Shufeng Chen
DOI:10.1039/d2cc03080b
日期:——
A convenient Y(OTf)3-catalyzed cascade formal [4 + 2] cyclization approach for the formation of 1,4-benzoxazine scaffolds from benzoxazoles and propargyl alcohols through a ring-opening and regioselective ring-closure process has been developed. By using this mild and practical protocol, a broad range of aldehyde-containing 1,4-benzoxazine compounds were prepared in moderate to excellent yields with
已经开发了一种方便的 Y(OTf) 3 -催化级联形式 [4 + 2] 环化方法,用于通过开环和区域选择性闭环过程从苯并恶唑和炔丙基醇形成 1,4-苯并恶嗪支架。通过使用这种温和而实用的方案,可以以中等至优异的产率制备多种含醛的 1,4-苯并恶嗪化合物,并具有良好的官能团耐受性。机理研究表明,苯并恶唑与炔丙基阳离子的 S N 1 亲核取代参与了这一转变。