Condition-controlled selective synthesis of coumarins and flavones from 3-(2-hydroxyphenyl)propiolates and iodine
摘要:
2H-Chromen-2-ones (coumarins) and 4H-chromen-4-ones (flavones) were selectively prepared via the reaction of 3-(2-hydroxyphenyl)propiolates with iodine in toluene and N,N-dimethylformide, respectively. (C) 2011 Elsevier Ltd. All rights reserved.
Stereo- and Regioselective Palladium-Catalysed Hydroarylation and Hydrovinylation of Functionalised Alkynes: a Route to Substituted <i>Z</i>-2-Cinnamyl Esters, 3-Chromen-2-ols, and Coumarins
作者:Sandro Cacchi、Giancarlo Fabrizi、Leonardo Moro、Paola Pace
DOI:10.1055/s-1997-1040
日期:——
The palladium-catalysed hydroarylation and hydrovinylation of methyl 3-phenylpropynoate and 3,3-diethyoxy-1-(o-tetrahydropyranyloxy)phenyl-1-propyne with aryl and vinyl halides or triflates in the presence of Pd(OAc)2 and KOOCH has been studied. The reaction affords stereoselectively syn addition products. The regiochemical outcome appears to be controlled by steric effects and the new carbon-carbon bond is generated preferentially on the carbon far from the aromatic ring ligated to the acetylenic carbon. The reaction can be applied to the synthesis of 3-substituted-3-chromen-2-ols and 3-substituted coumarins.
One-pot synthesis of a natural product inspired pyrrolocoumarine compound collection by means of an intramolecular 1,3-dipolar cycloaddition as key step
作者:Srinivasa Rao Vidadala、Herbert Waldmann
DOI:10.1016/j.tetlet.2015.01.021
日期:2015.6
A general, sequential and efficient one-pot synthesis of natural product inspired chromeno[3,4-b]pyrrol-4(3H)-ones is described. The one-pot reaction sequence consists of N-Boc deprotection of a N-substituted Boc-glycine O-aryl ester embodying an ortho-alkyne substituent, azomethine ylide generation with an aldehyde, subsequent intramolecular 1,3-dipolarcycloaddition with the alkyne followed by oxidative
描述了由天然产物激发的chromeno [3,4- b ]吡咯-4(3 H)-ones的一般,顺序和有效的一锅合成。一锅法反应序列由体现邻炔烃取代基的N-取代Boc-甘氨酸O-芳基酯的N-Boc脱保护,乙醛生成甲亚胺基叶立德,随后与炔烃分子内进行1,3-偶极环加成通过氧化芳香化。这种合成方法使人们可以高效地获得一系列高度取代的各种吡咯香豆香豆素。
Condensed heteroaromatic ring systems. XXIV. Palladium-catalyzed cyclization of 2-substituted phenylacetylenes in the presence of carbon monoxide
The palladium-catalyzed reaction of 2-alkynylanilines and 2-alkynylphenols in the presence of carbon monoxide and methanol under basic conditions gave the sequential cyclization / carbonylation products, methyl 2-substituted indole and benzo[b]-furan-3-carboxylates. Similar reaction of 2-alkynylbenzamides gave 3-alkylidenisoindole derivatives.
在碱性条件下,在一氧化碳和甲醇存在下,钯催化的2-炔基苯胺和2-炔基苯酚的反应,依次得到环化/羰基化产物,2-甲基取代的吲哚和苯并[ b ]-呋喃-3-羧酸酯。2-炔基苯甲酰胺的类似反应得到3-亚烷基亚异吲哚衍生物。
(Ethoxycarbonyliodomethyl)triphenylphosphonium Iodide: A Convenient Reagent for the Direct Synthesis of β-Substituted Propiolic Acids<i>via</i>the Corresponding Esters
作者:Jaques Chenault、Jean-François E. Dupin
DOI:10.1055/s-1987-27983
日期:——
Reaction between (ethoxycarbonyliodomethyl)triphenylphosphonium iodide, potassium carbonate, and various aromatic or aliphatic aldehydes in a liquid solid two phases system gives ß-substituted propiolic esters. The corresponding acids are obtained in good yield by hydrolysis.
Transition-metal-free base catalyzed intramolecular cyclization of 2-ynylphenols for efficient and facile synthesis of 2-substituted benzo[<i>b</i>]furans
作者:Yong Liu、Tao Lu、Wei-Fang Tang、Jian Gao
DOI:10.1039/c8ra03882a
日期:——
A transition-metal-free basecatalyzedintramolecular cyclization of 2-ynylphenols was developed for the facile synthesis of 2-substituted benzo[b]furans. Various 2-aryl and 2-alkyl substituted benzo[b]furans can be obtained with good to excellent yields using readily available Cs2CO3 as the catalyst under mild reaction conditions. The broad substrates scope and the typical maintenance of vigorous
开发了一种无过渡金属碱催化的 2-炔基酚分子内环化,用于简便合成 2-取代的苯并[ b ]呋喃。使用容易获得的 Cs 2 CO 3作为催化剂,在温和的反应条件下,可以以良好至优异的收率获得各种 2-芳基和 2-烷基取代的苯并[ b ]呋喃。广泛的底物范围和克级高效效率的典型维持使该协议成为合成 2-取代苯并[ b ]呋喃衍生物的潜在实用方法。