scholarly journals The Chemoselective Reduction of Isoxazolineγ-Lactams Through Iminium Aza-Diels-Alder Reactions: A Short-Cut Synthesis of Aminols as Valuable Intermediates towards Nucleoside Derivatives

2012 ◽  
Vol 2012 ◽  
pp. 1-10
Author(s):  
Misal Giuseppe Memeo ◽  
Mariella Mella ◽  
Paolo Quadrelli
Keyword(s):  
Catalytic Oxidation ◽  
Ring Opening ◽  
Diels Alder ◽  
Mild Conditions ◽  
Nucleoside Synthesis ◽  
Conformationally Locked

Isoxazolineγ-lactams are prepared starting from the regioisomeric cycloadducts of benzonitrile oxide to theN-alkyl 2-azanorbornenes taking advantage of the efficient catalytic oxidation by RuO4. The reduction of the amide groups is easily conducted in the presence of LiAlH4under mild conditions, which allowed for the chemoselective reduction of the amide moiety followed by ring opening to afford the desired conformationally locked isoxazoline-carbocyclic aminols, as valuable intermediates for nucleoside synthesis.

Masked Bisketenes as Diels–Alder Dienes

2020 ◽  
Author(s):  
Isuru Dissanayake ◽  
Jacob Hart ◽  
Emma Becroft ◽  
Christopher Sumby ◽  
Christopher Newton
Keyword(s):  
Natural Product ◽  
Ring Opening ◽  
Alder Reaction ◽  
Diels Alder ◽  
Natural Product Synthesis ◽  
One Pot ◽  
Neuroprotective Agent ◽  
Mild Conditions ◽  
Diels Alder Reaction

<div> <div> <div> <p>2,5-Bis(<i>tert</i>-butyldimethylsilyloxy)furans are established as masked vicinal bisketenes for application as dienes in the Diels–Alder reaction. Cycloaddition with olefinic dienophiles, under exceptionally mild conditions, enables convergent access to highly substituted <i>para</i>-hydroquinones in unprotected form via a one-pot Diels–Alder/ring-opening/tautomerization sequence. The synthesis of <i>para</i>-benzoquinones from acetylenic dienophiles, including benzynes, is also demonstrated, and 2,5-bis(<i>tert</i>-butyldimethylsilyloxy)pyrroles are established as competent dienes for the synthesis of <i>para</i>-iminoquinones. Application in natural product synthesis enables gram-scale access to the neuroprotective agent (±)-indanostatin. </p> </div> </div> </div>

Bisketene Equivalents as Diels–Alder Dienes

2020 ◽  
Author(s):  
Isuru Dissanayake ◽  
Jacob Hart ◽  
Emma Becroft ◽  
Christopher Sumby ◽  
Christopher Newton
Keyword(s):  
Natural Product ◽  
Ring Opening ◽  
Alder Reaction ◽  
Diels Alder ◽  
Natural Product Synthesis ◽  
One Pot ◽  
Neuroprotective Agent ◽  
Mild Conditions ◽  
Diels Alder Reaction

<div> <div> <div> <p>2,5-Bis(<i>tert</i>-butyldimethylsilyloxy)furans are established as vicinal bisketene equivalents for application as dienes in the Diels–Alder reaction. Cycloaddition with olefinic dienophiles, under exceptionally mild conditions, enables convergent access to highly substituted <i>para</i>-hydroquinones in unprotected form via a one-pot Diels–Alder/ring-opening/tautomerization sequence. The synthesis of <i>para</i>-benzoquinones from acetylenic dienophiles, including benzynes, is also demonstrated, and 2,5-bis(<i>tert</i>-butyldimethylsilyloxy)pyrroles are established as competent dienes for the synthesis of <i>para</i>-iminoquinones. Application in natural product synthesis enables gram-scale access to the neuroprotective agent (±)-indanostatin.</p> </div> </div> </div>

Oxidation of 2-methylpyrroles with perchlorinated iron(III) metalloporphyrin catalysts: a versatile synthesis of symmetric and asymmetric dipyrromethanes

1998 ◽  
Vol 76 (10) ◽  
pp. 1467-1473 ◽  
Author(s):  
Veranja Karunaratne ◽  
David Dolphin
Keyword(s):  
Catalytic Oxidation ◽  
Allylic Alcohols ◽  
The Novel ◽  
Efficient Synthesis ◽  
Mild Conditions ◽  
Metalloporphyrin Catalysts

A variety of substituted 2-methylpyrroles (3-8) were oxidized using the metalloporphyrin catalysts iron(III) meso-tetra(2,6-dichloro-3-sulphonatophenyl)-β-octachloroporphyrin chloride 1 and iron(III) meso-tetra(2,6-dichlorophenyl)-β-octachloroporphyrin chloride 2 under very mild conditions. Treatment of the resulting allylic alcohols 3a-8a with α-free pyrroles 9 and 10 resulted in a very efficient synthesis of the corresponding dipyrromethanes 3b-8b and 3c-8c. Furthermore, the above allylic alcohols when treated with furfurylamine produced the novel (2-furylmethyl)-2-pyrrolylmethylamines 3d-8d.Key words: catalytic oxidation, metalloporphyrins, pyrroles, dipyrromethanes, polyhalogenated porphyrins.

scholarly journals Imidazolinium and amidinium salts as Lewis acid organocatalysts

2012 ◽  
Vol 8 ◽  
pp. 1798-1803 ◽  
Author(s):  
Oksana Sereda ◽  
Nicole Clemens ◽  
Tatjana Heckel ◽  
René Wilhelm
Keyword(s):  
Lewis Acid ◽  
Ring Opening ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction

The application of imidazolinium and amidinium salts as soft Lewis acid organocatalysts is described. These salts were suitable catalysts for the activation of unsaturated thioesters in a Diels–Alder reaction and in the ring opening of thiiranes and epoxides. The products were isolated in good yields. The mild catalysts did not cause desulfurization of the products containing a thiol or thiocarbonyl group.

Catalytic Oxidation of Alcohols with Polymer-Supported Ruthenium Complex under Mild Conditions.

ChemInform ◽  
2006 ◽  
Vol 37 (15) ◽  
Author(s):  
Qiao-xiang Kang ◽  
Ju-jie Luo ◽  
Yan-bin Bai ◽  
Zhi-wang Yang ◽  
Zi-qiang Lei
Keyword(s):  
Catalytic Oxidation ◽  
Ruthenium Complex ◽  
Mild Conditions ◽  
Oxidation Of Alcohols ◽  
Polymer Supported

Extraction combined catalytic oxidation desulfurization of petcoke in ionic liquid under mild conditions

Fuel ◽  
2020 ◽  
Vol 260 ◽  
pp. 116200 ◽  
Author(s):  
Hui Liu ◽  
Huanhuan Xu ◽  
Mingqing Hua ◽  
LinLin Chen ◽  
Yanchen Wei ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Catalytic Oxidation ◽  
Mild Conditions
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