scholarly journals Synthesis of Illisimonin a Skeleton by Intramolecular Diels–Alder Reaction of Ortho-Benzoquinones and Biomimetic Skeletal Rearrangement of Allo-Cedranes

Organics ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 306-312
Author(s):  
Takahiro Suzuki ◽  
Riko Nagahama ◽  
Muhammad Aiman Fariz ◽  
Yuki Yukutake ◽  
Kazutada Ikeuchi ◽  
...  

Illisimonin A is a new sesquiterpene isolated from Illicium simonsii, and it possesses a novel 5/5/5/5/5 pentacyclic skeleton. The tricyclic skeleton of illisimonin A, tricyclo[5.2.1.01,5]decane, is presumed to be biosynthesized from allo-cedranes via a skeletal rearrangement. Herein, we report the concise synthesis of highly oxidized allo-cedranes by an intramolecular Diels–Alder reaction using ortho-benzoquinones and demonstrate the biomimetic transformation of allo-cedranes by a retro-Claisen/aldol pathway.

1978 ◽  
Vol 31 (8) ◽  
pp. 1841 ◽  
Author(s):  
R Bergamasco ◽  
QN Porter ◽  
C Yap

3-Vinylindoles give adducts containing a benzo- or naphtho-carbazole ring system by 1,4-cycloadditionsto 1,4-benzoquinone and 1,4- naphthoquinone respectively. The adducts are readily dehydrogenated to the corresponding heterocyclic quinones. No skeletal rearrangement accompanies oxidation with oxygen in base.


1977 ◽  
Vol 30 (7) ◽  
pp. 1523 ◽  
Author(s):  
R Bergamasco ◽  
QN Porter

3-Vinylindene gives high yields of adducts with 1,4-benzoquinone, 1,4- naphthoquinone, and benzo[b]-thiophen 1,1-dioxide. The structures and stereochemistries of the adducts are confirmed by p.m.r. and mass spectrometry. The effects of various oxidation procedures on the 1,4- naphthoquinone adduct are described; no skeletal rearrangement accompanies oxidation with oxygen in base. Some adducts of 34sopropenylindene and 2-methyl-3-vinylindene are also described.


Synlett ◽  
1989 ◽  
Vol 1989 (01) ◽  
pp. 30-32
Author(s):  
Thomas V. Lee ◽  
Alistair J. Leigh ◽  
Christopher B. Chapleo

2020 ◽  
Author(s):  
Radu Talmazan ◽  
Klaus R. Liedl ◽  
Bernhard Kräutler ◽  
Maren Podewitz

We analyze the mechanism of the topochemically controlled difunctionalization of C60 and anthracene, where an anthracene molecule is transferred from one C60 monoadduct to another one under exclusive formation of equal amounts of C60 and the difficult to make antipodal C60 bisadduct. Our herein disclosed dispersion corrected DFT studies show the anthracene transfer to take place in a synchronous retro Diels-Alder/Diels-Alder reaction: an anthracene molecule dissociates from one fullerene under formation of an intermediate, while already undergoing stabilizing interactions with both neighboring fullerenes, facilitating the reaction kinetically. In the intermediate, a planar anthracene molecule is sandwiched between two neighboring fullerenes and forms equally strong "double-decker" type pi-pi stacking interactions with both of these fullerenes. Analysis with the distorsion interaction model shows that the anthracene unit of the intermediate is almost planar with minimal distorsions. This analysis sheds light on the existence of noncovalent interactions engaging both faces of a planar polyunsaturated ring and two convex fullerene surfaces in an unprecedented 'inverted sandwich' structure. Hence, it sheds light on new strategies to design functional fullerene based materials.<br>


2016 ◽  
Vol 20 (22) ◽  
pp. 2421-2442 ◽  
Author(s):  
Kévin Cottet ◽  
Maria Kolympadi ◽  
Dean Markovic ◽  
Marie-Christine Lallemand

2014 ◽  
Vol 10 (6) ◽  
pp. 951-960
Author(s):  
Orazio Attanasi ◽  
Luca Bianchi ◽  
Maurizio D’Auria ◽  
Gianfranco Favi ◽  
Fabio Mantellini ◽  
...  

2018 ◽  
Vol 15 (2) ◽  
pp. 221-229 ◽  
Author(s):  
Shah Bakhtiar Nasir ◽  
Noorsaadah Abd Rahman ◽  
Chin Fei Chee

Background: The Diels-Alder reaction has been widely utilised in the syntheses of biologically important natural products over the years and continues to greatly impact modern synthetic methodology. Recent discovery of chiral organocatalysts, auxiliaries and ligands in organic synthesis has paved the way for their application in Diels-Alder chemistry with the goal to improve efficiency as well as stereochemistry. Objective: The review focuses on asymmetric syntheses of flavonoid Diels-Alder natural products that utilize chiral ligand-Lewis acid complexes through various illustrative examples. Conclusion: It is clear from the review that a significant amount of research has been done investigating various types of catalysts and chiral ligand-Lewis acid complexes for the enantioselective synthesis of flavonoid Diels-Alder natural products. The results have demonstrated improved yield and enantioselectivity. Much emphasis has been placed on the synthesis but important mechanistic work aimed at understanding the enantioselectivity has also been discussed.


2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Urbain C. Kassehin ◽  
Sèdami M. Fagla ◽  
Fernand A. Gbaguidi ◽  
Julien R. C. Prevost ◽  
Raphaël Frédérick ◽  
...  

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