Polarity Variation of Room Temperature Ionic Liquids and Its Influence on a Diels-Alder Reaction

Author(s):  
Richard A. Bartsch ◽  
Sergei V. Dzyuba
2007 ◽  
Vol 20 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Ana Vidiš ◽  
Gábor Laurenczy ◽  
Ernst Küsters ◽  
Gottfried Sedelmeier ◽  
Paul J. Dyson

2005 ◽  
Vol 347 (2-3) ◽  
pp. 266-274 ◽  
Author(s):  
Ana Vidiš ◽  
C. André Ohlin ◽  
Gábor Laurenczy ◽  
Ernst Küsters ◽  
Gottfried Sedelmeier ◽  
...  

2010 ◽  
Vol 8 (2) ◽  
pp. 356-360 ◽  
Author(s):  
Nitin Mirgane ◽  
Sandip Kotwal ◽  
Anil Karnik

AbstractIonic liquids (IL) are gaining importance as green solvents. Imidazolium ionic liquid [bmim]+[Cl]−, an environmentally benign solvent, was found to promote the Diels-Alder reaction between anthrone and maleimides at room temperature with excellent yields. The ionic liquid played a dual role as solvent and catalyst.


2015 ◽  
Vol 11 ◽  
pp. 576-582 ◽  
Author(s):  
Grzegorz Mlostoń ◽  
Paulina Grzelak ◽  
Maciej Mikina ◽  
Anthony Linden ◽  
Heinz Heimgartner

Selected hetaryl and aryl thioketones react with acetylenecarboxylates under thermal conditions in the presence of LiClO4 or, alternatively, under high-pressure conditions (5 kbar) at room temperature yielding thiopyran derivatives. The hetero-Diels–Alder reaction occurs in a chemo- and regioselective manner. The initially formed [4 + 2] cycloadducts rearrange via a 1,3-hydrogen shift sequence to give the final products. The latter were smoothly oxidized by treatment with mCPBA to the corresponding sulfones.


2015 ◽  
Vol 11 ◽  
pp. 169-173 ◽  
Author(s):  
Almaz Zagidullin ◽  
Vasili Miluykov ◽  
Elena Oshchepkova ◽  
Artem Tufatullin ◽  
Olga Kataeva ◽  
...  

Two different approaches have been employed to enhance the reactivity of 1-alkyl-1,2-diphospholes – the introduction of electron-withdrawing groups either at the phosphorus atoms or in the para-position of the arene ring. The alkylation of sodium 1,2-diphospha-3,4,5-triphenylcyclopentadienide with alkyl halides Hal-CH2-R (R = CN, COOEt, OMe, CH2OEt) results in corresponding 1-alkyl-3,4,5-triphenyl-1,2-diphospholes (alkyl = CH2CN (1a), CH2COOEt (1b), CH2OMe (1c), and (CH2)2OEt (1d)), which spontaneously undergo the intermolecular [4 + 2] cycloaddition reactions at room temperature to form the mixture of the cycloadducts, 2a–c, respectively. However the alkylation of sodium 1,2-diphospha-3,4,5-tri(p-fluorophenyl)cyclopentadienide with ethyl iodide leads to stable 1-ethyl-3,4,5-tris(p-fluorophenyl)-1,2-diphosphole (1e), which forms the [4 + 2] cycloadduct 2,3,4,4a,5,6-hexa(p-fluorophenyl)-1-ethyl-1,7,7a-triphospha-4,7-(ethylphosphinidene)indene (2e) only upon heating up to 60 °C. With further heating to 120 °C with N-phenylmaleimide, the cycloadducts 2a–c and 2e undergo the retro-Diels–Alder reaction and form only one product of the [4 + 2] cycloaddition reaction 3a–с, 3e with good yields up to 65%.


Heterocycles ◽  
2008 ◽  
Vol 76 (1) ◽  
pp. 381 ◽  
Author(s):  
Hiroto Nakano ◽  
Mitsuhiro Takeshita ◽  
Yasuhiro Nishiuchi ◽  
Kouichi Takahashi ◽  
Reiko Fujita ◽  
...  

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