Trans-Selective Conversions of γ-Hydroxy-α,β-Alkynoic Esters to γ-Hydroxy-α,β-Alkenoic Esters
摘要:
gamma-Hydroxy-alpha,beta-acetylenic esters are used as precursors to prepare gamma-hydroxy-alpha,beta-alkenoic esters by means of trans-selective additions of two hydrogen atoms or one hydrogen atom and one iodine atom across the triple bonds. These methods allow for the preparation of beta-substituted and alpha,beta-disubstituted alkenoic esters in highly stereoselective manners.
The palladium-tributylammonium formate reagent in the stereoselective hydrogenation, and stereo- and regioselective hydroarylation of alkyl 4-hydroxy-2-alkynoates: a route to substituted butenolides
The reaction of aryl iodides with alkyl 4-hydroxy-2-alkynoates in the presence of formic acid, tri-n-butylamine and a palladium(II) catalyst provides a convenient route to functionalized substituted butenolides through a one pot hydroarylation/cyclization reaction. In the presence of formic acid, tri-n-butylamine and a palladium(II) catalyst, alkyl 4-hydroxy-2-alkynoates undergo a one pot hydrogenation/cyclization
Cationic Rhodium(I) Complex-Catalyzed [3 + 2] and [2 + 1] Cycloadditions of Propargyl Esters with Electron-Deficient Alkynes and Alkenes
作者:Yu Shibata、Keiichi Noguchi、Ken Tanaka
DOI:10.1021/ja102418h
日期:2010.6.16
A cationic rhodium(I) complex, [Rh(cod)(2)]SbF(6), catalyzes the [3 + 2] cycloaddition of propargyl esters with dialkyl acetylenedicarboxylates in good yields, presumably through carbonyl-stabilized cationic rhodium(I) alkenylcarbene intermediates. The same rhodium(I) complex also catalyzes the [2 + 1] cycloaddition (cyclopropanation) of propargyl esters with N,N-disubstituted acrylamides in good yields
New procedures for the synthesis of 3(2H)-furanones and 4-alkoxy-2(5H)-furanones are reported. Reaction of ketones with the lithium salt of propynal diethyl acetal, followed by treatment of the resulting 4-hydroxy-2-alkynal diethyl acetals with sulfuric acid–methanol, gave 2,2-disubstituted 3(2H)-furanones. The action of a polymer reagent Hg/Nafion-H upon 4–hydroxy-2-alkynones produced 2,2,5-trisubstituted
Expeditious synthesis of pyrano[2,3,4-de]quinolines via Rh(<scp>iii</scp>)-catalyzed cascade C–H activation/annulation/lactonization of quinolin-4-ol with alkynes
作者:Gang Liao、Hong Song、Xue-Song Yin、Bing-Feng Shi
DOI:10.1039/c7cc04113f
日期:——
One-step synthesis of tetracyclic pyrano[2,3,4-de]quinolones via Rh(iii)-catalyzed cascade C–H activation/annulation/lactonization is described.
Ionic Liquids—Advanced Reaction Media for Organic Synthesis
作者:Nikolai V. Ignat'ev、Michael Schulte、Karsten Koppe、Peter Barthen、Sergei G. Zlotin、Nina N. Makhova、Aleksei B. Sheremetev、Anabela A. Valente
DOI:10.1080/10426507.2010.538557
日期:2011.5.1
Abstract The advantages in the application of ionicliquids as reaction media in organicsynthesis, i.e., in the preparation of chromane derivatives, substituted pyrazines, 4-aminofuran-2(5H)-ones, or in bromination of Levulinic acid or dehydration of alcohols, saccharides, and polysaccharides, have been demonstrated on several examples. Ionicliquids with Brønsted acidity have been shown to possess