The Reactivity of 4-Hydroxy- and 4-Silyloxy-1,5-allenynes with Homogeneous Gold(I) Catalysts
作者:Michael Wegener、Stefan F. Kirsch
DOI:10.1021/acs.orglett.5b00348
日期:2015.3.20
Two new gold(I)-catalyzed cascade reactions of 4-hydroxy- and 4-silyloxy-1,5-allenynes are disclosed, offering access to a variety of mono- and bicyclic, polyunsaturated carbonyl compounds. The diverse reactivity observed for the investigated allenyne system is controlled by the nature of the unsaturated substrate: Allenynes bearing a free hydroxyl group engage in what is likely an oxycyclization/allene-ene
Two-step synthesis of β-alkyl chalcones and their use in the synthesis of 3,5-diaryl-5-alkyl-4,5-dihydropyrazoles
作者:Christopher D. Cox、Michael J. Breslin、Brenda J. Mariano
DOI:10.1016/j.tetlet.2003.12.026
日期:2004.2
We report a simple and efficient two-step synthesis of variously substituted β-alkyl chalcones (7) from the corresponding Weinreb amide and a terminal alkyne, and that these chalcones are useful intermediates for the synthesis of medicinally interesting 3,5-diaryl-5-alkyl-4,5-dihydropyrazoles (6). The current methodology allows for the incorporation of many substitution patterns not available from
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。
Acid-Catalyzed Cyclization Reactions of Substituted Acetylenic Ketones: A new Approach for the Synthesis of 3-Halofurans, Flavones, and Styrylchromones
作者:Daniel Obrecht
DOI:10.1002/hlca.19890720305
日期:1989.5.3
Acetylenic acetals of type I(Scheme 1) and acetylenic ketones of type III(Scheme 1), 37 and 38(Scheme 7) are versatile synthetic precursors for the synthesis of various heterocycles by acid-catalyzed cyclization reactions. By this way, substituted 3-halofurans of type II and IV(Scheme 1) and flavones and styrylchromones (Scheme 7) can be synthesized in good-to-excellent yields. The high degree of regioselectivity
A novel one-pot three-component synthesis of 3-halofurans and sequential Suzuki coupling
作者:Alexei S. Karpov、Eugen Merkul、Thomas Oeser、Thomas J. J. Müller
DOI:10.1039/b502324f
日期:——
electrophilic addition to an ynone, with concomitant deprotection and cyclocondensation, opens a new one-potsynthesis of 3-halofurans; the method can be readily elaborated to a new sequential Sonogashira-addition-cyclocondensation-Suzuki reaction to furnish 2,3,5-trisubstituted furans in a one-pot fashion.