Gold‐Catalyzed Bicyclic and [3+2]‐Annulations of Internal Propargyl Alcohols with Nitrones and Imines To Yield to Two Distinct Heterocycles
作者:Sayaji Arjun More、Tzu‐Hsuan Chao、Mu‐Jeng Cheng、Rai‐Shung Liu
DOI:10.1002/adsc.202001119
日期:2021.1.19
4‐a]indoles from 1‐oxo‐3‐yn‐4‐ols and nitrones is described; this new bicyclic annulation presents the first examples that internal alkynes can react with nitrones to undergo an oxoarylation route. DFT calculations indicate a [3,3]‐sigmatropic shift of initial alkenylgold intermediates to elude the intermediacy of gold carbenes. We also developed new [3+2]‐annulations of the same 1‐oxo‐3‐yn‐4‐ols with imines
描述了一种由金催化的由1-氧代3-yn-4-醇和硝酮合成的1,3-二氢恶唑并[3,4- a ]吲哚的方法;这种新的双环环化反应是第一个实例,表明内部炔烃可以与硝酮反应进行羰基化反应。DFT计算表明,初始烯基金中间体发生了[3,3]-σ位移,从而避开了金卡宾的中间产物。我们还用亚胺开发了相同的1-oxo-3-yn-4醇与新的[3 + 2]环,有效地生成了oxazolidin-4-yylne衍生物。这些1-oxo-3-ynes的束缚醇可捕获其亚稳的2-azadienium中间体,从而实现新颖的环化反应。我们的机械分析表明,尽管两种产品在结构上相关,但它们是由两个独立的系统生产的。
An Expedient Route for the Stereoselective Construction of Bridged Polyheterocyclic Ring Systems Using the Tandem “Pincer” Diels−Alder Reaction
作者:Mark Lautens、Eric Fillion
DOI:10.1021/jo9701593
日期:1997.6.1
The tandem "pincer" Diels-Alder reaction, consisting of two consecutive [4 + 2] cycloadditions between two dienes and an acetylenic bis-dienophile, has been applied toward the rapid construction of bridged polyoxacyclic ring systems when furan derivatives are used as the diene components. The study has demonstrated the stereoselectivity (exo-exo adduct), the chemoselectivity ("pincer" vs "domino")
Efficient Stereoselective Syntheses of Cyclic Amino Acids via Michael-Induced Ring-Closing Reactions
作者:Matthias Pohlman、Uli Kazmaier
DOI:10.1021/ol034777j
日期:2003.7.1
[reaction: see text] Zn-chelated glycine ester enolates are highly efficient nucleophiles for the synthesis of trans-methoxycarbonylcyclopropyl- and cyclobutylglycines by domino sequences of Michael additions and subsequent ring closures. They react to give the anti isomers with high yields and excellent diastereoselectivities.
Functionalized Hexahydropyrrolo[2,1‐
<i>b</i>
]oxazoles from Catalyst‐Free Annulation of Δ
<sup>1</sup>
‐Pyrrolines with Electron‐Deficient Propargylic Alcohols
作者:Ludmila A. Oparina、Dmitrii A. Shabalin、Anastasiya G. Mal'kina、Nikita A. Kolyvanov、Lyudmila A. Grishchenko、Igor' A. Ushakov、Alexander V. Vashchenko、Boris A. Trofimov
DOI:10.1002/ejoc.202000582
日期:2020.7.23
Catalyst‐free annulation of Δ1‐pyrrolines with electron‐deficient propargylic alcohols was demonstrated allowing the formation of functionalized hexahydropyrrolo[2,1‐b ]oxazoles in good to excellent yields.
证实了无电子的炔丙基醇对Δ1-吡咯啉的无催化剂环化反应,可以形成官能化的六氢吡咯并[2,1- b ]恶唑,收率高至优异。
Siloxanes as temporary tethers in [2+2] photocycloadditions
作者:Michael T. Crimmins、Lisa E. Guise
DOI:10.1016/0040-4039(94)88312-2
日期:1994.3
Intramolecular [2+2] photocycloadditions utilizing siloxanes as temporary tethers between an enone and olefin results in the products of an intermolecular photocycloaddition with the selectivity of the intramolecularreaction after cleavage of the temporary tether.