Wittig Reactions in Water Media Employing Stabilized Ylides with Aldehydes. Synthesis of α,β-Unsaturated Esters from Mixing Aldehydes, α-Bromoesters, and Ph<sub>3</sub>P in Aqueous NaHCO<sub>3</sub>
作者:Amer El-Batta、Changchun Jiang、Wen Zhao、Robert Anness、Andrew L. Cooksy、Mikael Bergdahl
DOI:10.1021/jo070665k
日期:2007.7.1
range of stabilized ylides and aldehydes. Despite sometimes poor solubility of the reactants, good chemical yields normally ranging from 80 to 98% and high E-selectivities (up to 99%) are achieved, and the rate of the reactions in water is unexpectedly accelerated. The efficiency of water as a medium in the Wittig reaction is compared to conventional organic solvents ranging from carbon tetrachloride
An expedient approach to synthesize fluorescent 3-substituted 4H-quinolizin-4-ones via (η<sup>4</sup>-vinylketene)-Fe(CO)<sub>3</sub> complexes
作者:Alfredo Rosas-Sánchez、Rubén A. Toscano、José G. López-Cortés、M. Carmen Ortega-Alfaro
DOI:10.1039/c4dt03021d
日期:——
From simple starting materials, an efficient methodology for the synthesis of 3-substituted 4H-quinolizin-4-ones using (η4-vinylketene)-Fe(CO)3 complexes as key intermediates was developed. Fluorescent properties and quantum yields were determined.
Water is demonstrated to be an excellent medium for the Wittigreaction employing stabilized ylides and aldehydes. Although the solubility in water appears to be an unimportant characteristic in achieving good chemical yields and E/Z-ratios, the rate of Wittigreactions in water is unexpectedly accelerated.
Direct addition of 2-methylazines to aryl glyoxals for the synthesis of α-hydroxy ketones
作者:Binbin Li、Huiping Wei、Haiyan Li、Olga P. Pereshivko、Vsevolod A. Peshkov
DOI:10.1016/j.tetlet.2015.07.053
日期:2015.9
A catalyst-free protocol for the reaction of 2-methylazines and aryl glyoxal hydrates leading to alpha-hydroxy ketones bearing azaarene moiety is described. The process is operationally simple and can be applied to a broad range of substrates. (C) 2015 Elsevier Ltd. All rights reserved.
Synthesis of Functionalized Cyclopentenes through Catalytic Asymmetric [3+2] Cycloadditions of Allenes with Enones