Superoxide mediated isomerization of 4-aryl-but-1-ynes to 1-aryl-1,3-butadienes
摘要:
A new role of superoxide ion in the isomerization of homobenzylic acetylenes leading to 1-aryl-1,3-butadienes is reported. The unconventional reagent 1(02 is found to be superior in performing this kind of isomerization over other the commonly used bases. For substrates containing arene moiety and triple bond connected through more than two methylene groups, and for propargylcyclohexanol the reagent selectively effected migration of the triple bond. Reactivity of 1(02 towards the substrates having disubstitution at benzylic position varied depending on the nature of the substitution, alkyl-substitution lead to isomerization to give mixture of allene (an intermediate in the isomerization of acetylene to 1,3-butadiene) and triple bond migration product; whereas phenyl-substituted compound gave 1,3-diene. The utility of the methodology was demonstrated through a Diels-Alder reaction of one of the dienes obtained by the isomerization with suitable dienophiles. (C) 2015 Elsevier Ltd. All rights reserved.
Efficient Synthesis of 3-Chloromethyl-2(5<i>H</i>)-furanones and 3-Chloromethyl- 5,6-dihydropyran-2-ones via the PdCl<sub>2</sub>-Catalyzed Chlorocyclocarbonylation of 2,3- or 3,4-Allenols
作者:Xin Cheng、Xuefeng Jiang、Yihua Yu、Shengming Ma
DOI:10.1021/jo8015677
日期:2008.11.21
was formed between the center carbon atom of the allene moiety and the hydroxyl oxygen, which was established by the X-ray single crystal diffraction study of gamma-lactone 3p. The highly opticallyactive 3-chloromethyl-2(5H)-furanones could be easily prepared from the readily available opticallyactive 2,3-allenols. A mechanism for this reaction was proposed.
Copper (I) Iodide-Catalyzed One-Step Preparation of Functionalized Allenes from Terminal Alkynes: Amine Effect
作者:Jinqiang Kuang、Hongwen Luo、Shengming Ma
DOI:10.1002/adsc.201100772
日期:2012.3.16
An efficient one‐step synthesis of functionalizedallenesfrom readily available functionalizedterminal alkynes and aldehydes by applying the effect of a dialkylamine has been developed. The protocol is catalyzed by copper(I) iodide and the dialkylamine is believed to play a very important role in the transformation.
An Efficient Synthesis of Terminal Allenes from Terminal 1-Alkynes
作者:Jinqiang Kuang、Shengming Ma
DOI:10.1021/jo802391x
日期:2009.2.20
We have developed a modified method for the synthesis of terminalallenesfromterminal 1-alkyne: The reaction of 1-alkynes with 1.8 equiv of Cy2NH and 2.5 equiv of paraformaldehyde mediated by CuI (0.5 equiv) in refluxing dioxane may produce terminalallenes in much higher yields than the previously reported protocol and many functional groups such as mesylate, hydroxyl group, ether, amide, etc. may
Room temperature Fe(NO3)3·9H2O/TEMPO/NaCl-catalyzed aerobic oxidation of homopropargylic alcohols
作者:Jinxian Liu、Shengming Ma
DOI:10.1016/j.tet.2013.08.082
日期:2013.11
and eco-friendly aerobicoxidation of homopropargylic alcohols using Fe(NO3)3·9H2O/TEMPO/NaCl as catalysts at roomtemperature under atmospheric pressure was developed affording corresponding homopropargylic ketones with moderate to good yields. Aryl, heteroaryl as well as alkyl 1,2-allenic ketones were obtained by the isomerization of corresponding terminal homopropargylic ketones through column chromatographic
使用的Fe homopropargylic醇的实际和生态友好的有氧氧化(NO 3)3 ·9H 2 O / TEMPO / NaCl的如在大气压下室温催化剂的开发得到对应homopropargylic酮与中度至良好的产率。芳基,杂芳基以及烷基1,2-丙二烯酮类通过柱层析后处理在硅胶上相应的端子homopropargylic酮的异构化获得的。
A practical procedure of propargylation of aldehydes
作者:Papiya Ghosh、Angshuman Chattopadhyay
DOI:10.1016/j.tetlet.2012.07.021
日期:2012.9
An operationally simple procedure of propargylation of aldehydes in moist solvent (distilled THF) has been developed through direct addition of propargyl bromide to aldehyde substrates mediated with low valent iron or tin. The metals were spontaneously prepared in situ employing bimetal redox strategy. Using different aldehydes as substrates (3a–k) both these metal mediated reactions took place producing