Silica Gel Catalyzed Conversion of Dialkyl 2-(2-Hydroxy-1-naphthyl)-3-(1,1,1-triphenyl-λ 5 -phosphanylidene) Succinates to Alkyl 3-Oxo-3 H -benzo[ f ]chromene-1-carboxylates in Solvent-free Conditions
摘要:
Protonation of the highly reactive 1:1 intermediates produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates by 2-hydroxynaphthalene leads to vinyltriphenylphosphonium salts, which undergo aromatic electrophilic substitution reaction with conjugate base to produce dialkyl 2-(1-hydroxy-2-naphthyl)-3-(1,1,1-triphenyl-lambda(5)-phosphanylidene) succinates. Silica gel was found to catalyze conversion of dialkyl 2-(1-hydroxy-2-naphthyl)-3-(1,1,1-triphenyl-lambda(5)-phosphanylidene) succinates to alkyl 3-oxo-3H-benzo[f]chromene-1-carboxylates in solvent-free conditions at 60degreesC in fairly good yields.
Phosphinite ionic liquid (IL-OPPh2) as a recyclable reagent for the efficient synthesis of coumarins under microwave irradiation conditions
作者:H. Valizadeh、H. Gholipour、M. Mahmoudian
DOI:10.1007/bf03245917
日期:2011.9
the efficient synthesis of 4-substituted coumarins via the reaction of di(methyl or ethyl) acetylenedicarboxylate with phenolic compounds under microwave irradiation conditions. The effects of parameters such as the amount of the phosphinite ionic liquid, reaction temperature and reaction time on this procedure were investigated. Products were obtained in good yields using this mild and one-pot methodology
intermediates, produced in the reactionbetweentriphenylphosphine and dialkyl acetylenedicarboxylates, by phenols (1-hydroxynaphthalene, 2-hydroxynaphthalene, 4-bromophenol, 2-hydroxybenzaldehyde, and 5-bromo-2-hydroxyben- zaldehyde) leads to vinyltriphenylphosphonium salts, which undergo electrophilic substitutionreaction with conjugate base to produce corresponding stabilized phosphorus ylides. Microwave was
Abstract A convenient one-potsynthesis of coumarin derivatives from the three-component reaction of triphenylphosphine, an acetylenicester, and a phenol (1-naphthol, 2-naphthol and benzo[1,3]dioxol-5-ol) in the presence of a catalytic amount (4.5 mol%) of ß-cyclodextrin as a nanocatalyst and nanoreactor is reported. This methodology is of interest due to the use of water in the presence of this “ß-cyclodextrin
Synthesis of Dimethyl 2-(2,4,6-Trimethylphenoxy)-3-triphenylphosphoniobutanedioate and its Application in Intramolecular Wittig Reactions
作者:Issa Yavari、Farahnaz Nourmohammadian、Hamid R. Bijanzadeh
DOI:10.1080/10426500211709
日期:2002.5.1
Protonation of the reactive 1:1 intermediate produced in the reaction between triphenylphosphine and dimethyl acetylenedicarboxylate by 2,4,6-trimethylphenol leads to a stable ylide in high yield, which is employed in intramolecular Wittigreactions.
Manganese(II) Sulfate Powder is an Efficient Catalyst for the Synthesis of Coumarins from <i>In Situ</i> Generated Stabilized Phosphorus Ylides in Solvent-Free Conditions
reactive 1:1 intermediates, produced in the reactionbetweentriphenylphosphine and dialkyl acetylenedicarboxylates, by phenols (1-hydroxynaphthalene, 2-hydroxynaphthalene, and 4-bromophenol) leads to vinyltriphenylphosphonium salts, which undergo aromatic electrophilic substitutionreaction with conjugate base to produce corresponding stabilized phosphorus ylides. Manganese(II) sulfate powder was found
摘要 三苯基膦与二烷基乙炔二羧酸酯反应产生的高反应性 1:1 中间体,由苯酚(1-羟基萘、2-羟基萘和 4-溴苯酚)质子化生成乙烯基三苯基鏻盐,与共轭物发生芳香族亲电取代反应。生成相应的稳定磷叶立德。发现硫酸锰 (II) 粉末可在 90°C 的无溶剂条件下催化稳定的磷叶立德转化为香豆素,原因是 1 小时的高转化率。还发现在无溶剂条件下,在无溶剂条件下,在硫酸锰 (II) 粉末存在下,微波可在 1 分钟内以 1 KW 的微波功率催化相同的反应。