Efforts Toward a Synthesis of Crotogoudin and Crotobarin

Synlett ◽  
2017 ◽  
Vol 28 (14) ◽  
pp. 1758-1762 ◽  
Author(s):  
Duy Mai ◽  
Dmitriy Uchenik ◽  
Christopher Vanderwal
Keyword(s):  
Cascade Reaction ◽  
Diels Alder ◽  
Cope Rearrangement ◽  
Radical Chemistry ◽  
Phenolic Oxidation ◽  
Set Up

Two synthesis designs for the diterpenoid crotogoudin are discussed, and efforts to achieve each are described. First, a Cope rearrangement/intramolecular Diels–Alder cascade reaction was investigated. Second, a bioinspired sequence of cationic bicyclization and A-ring oxidative fragmentation set-up for a lactonization induced by a phenolic oxidation, ultimately providing a tricyclic intermediate that required only installation of the bridging ring of the salient bicyclo[2.2.2]octane system. This last endeavor was fraught with difficulty, but did lead to the development of conditions for cyclization of related keto-alkenes via manganese(III)-based radical chemistry.

Uncatalyzed diastereoselective synthesis of alkyliminofurochromone-derived benzylmalononitriles via a three-component cascade reaction: competition between Diels–Alder cycloaddition and Michael addition

2021 ◽  
Author(s):  
Mohammad Bagher Teimouri ◽  
Zahra Mokhtare ◽  
Hamid Reza Khavasi
Keyword(s):  
Michael Addition ◽  
Heterocyclic Ring ◽  
Cascade Reaction ◽  
Diels Alder ◽  
Chemical Bonds ◽  
Diastereoselective Synthesis ◽  
Atom Economy ◽  
One Pot

Three new chemical bonds and three stereogenic centres and one heterocyclic ring were assembled stereoselectively in a convenient high atom-economy one-pot operation.

scholarly journals Grafting of adipic anhydride to carbon nanotubes through a Diels-Alder cycloaddition/oxidation cascade reaction

Carbon ◽  
2016 ◽  
Vol 98 ◽  
pp. 421-431 ◽  
Author(s):  
Rui Filipe Araújo ◽  
Maria Fernanda Proença ◽  
Carlos Jorge Silva ◽  
Tarsila G. Castro ◽  
Manuel Melle-Franco ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Cascade Reaction ◽  
Diels Alder

Diels-Alder Cycloaddition: (+)-Armillarivin (Banwell), Gelsemiol (Gademann), (+)-Frullanolide (Liao), Myceliothermophin A (Uchiro), Peribysin E (Reddy), Caribenol A (Li/Yang)

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Elevated Pressure ◽  
Diels Alder ◽  
Cope Rearrangement ◽  
National Chemical Laboratory ◽  
Chemical Laboratory ◽  
Enantiomerically Pure ◽  
Peking University ◽  
National University ◽  
Diastereoselective Addition ◽  
The University

Martin G. Banwell of the Australian National University prepared (Org. Lett. 2013, 15, 1934) the enantiomerically pure diol 1 by fermentation of the aromatic precursor. Diels-Alder addition of cyclopentenone 2 proceeded well at elevated pressure to give 3, the precursor to (+)-armillarivin 4. Karl Gademann of the University of Basel found (Chem. Eur. J. 2013, 19, 2589) that the Diels-Alder addition of 6 to 5 proceeded best without solvent and with Cu catalysis to give 7. Reduction under free radical conditions led to gelsemiol 8. Chun-Chen Liao of the National TsingHua University carried out (Org. Lett. 2013, 15, 1584) the diastereoselective addition of 10 to 9. A later oxy-Cope rearrangement established the octalin skeleton of (+)-frullanolide 12. D. Srinivasa Reddy of CSIR-National Chemical Laboratory devised (Org. Lett. 2013, 15, 1894) a strategy for the construction of the angularly substituted cis-fused aldehyde 15 based on Diels-Alder cycloaddition of 14 to the diene 13. Further transformation led to racemic peribysin-E 16. An effective enantioselective catalyst for dienophiles such as 14 has not yet been developed. Hiromi Uchiro of the Tokyo University of Science prepared (Tetrahedron Lett. 2012, 53, 5167) the bicyclic core of myceliothermophin A 19 by BF3•Et2O-promoted cyclization of the tetraene 17. The single ternary center of 17 mediated the formation of the three new stereogenic centers of 18, including the angular substitution. En route to caribenol A 22, Chuang-Chuang Li and Zhen Yang of the Peking University Shenzen Graduate School assembled (J. Org. Chem. 2013, 78, 5492) the triene 20 from two enantiomerically pure precursors. Inclusion of the radical inhibitor BHT sufficed to suppress competing polymerization, allowing clean cyclization to 21. Methylene blue has also been used (J. Am. Chem. Soc. 1980, 102, 5088) for this purpose.

scholarly journals A chiral cobalt(ii) complex catalyzed enantioselective aza-Piancatelli rearrangement/Diels–Alder cascade reaction

2020 ◽  
Vol 11 (15) ◽  
pp. 3862-3867 ◽  
Author(s):  
Bin Shen ◽  
Qianwen He ◽  
Shunxi Dong ◽  
Xiaohua Liu ◽  
Xiaoming Feng
Keyword(s):  
Cascade Reaction ◽  
Diels Alder ◽  
Complex Catalyst

An asymmetric aza-Piancatelli rearrangement/Diels–Alder cascade reaction between 2-furylcarbinols and N-(furan-2-ylmethyl)anilines was realized by using a chiral N,N′-dioxide/cobalt(ii) complex catalyst.

A Caveat Concerning Anionic Oxy-cope Rearrangements Within Bicyclo[2.2.2]octenyl Frameworks

1996 ◽  
Vol 49 (5) ◽  
pp. 639 ◽  
Author(s):  
MG Banwell ◽  
JR Dupuche ◽  
RW Gable
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Cope Rearrangement ◽  
Diels Alder Reaction ◽  
Cope Rearrangements ◽  
Potassium Hydride

Compounds (10), (15) and (16) all react with potassium hydride at 0°C to give, via retro- Diels-Alder reaction, 1-methylnaphthalene (12) in 60-67% yield. No evidence could be obtained for the formation of a product derived from the anionic oxy-Cope rearrangement of substrate (16).

Cascade reaction involving Diels–Alder cascade: modular synthesis of amino α-pyrones, indolines and anilines

2018 ◽  
Vol 5 (24) ◽  
pp. 3574-3578 ◽  
Author(s):  
Yangyong Shen ◽  
Chaorong Wang ◽  
Wei Chen ◽  
Sunliang Cui
Keyword(s):  
Cascade Reaction ◽  
Alder Reaction ◽  
Diels Alder ◽  
Modular Synthesis ◽  
Diels Alder Reaction

A cascade reaction involving Diels–Alder reaction for modular synthesis of amino α-pyrones, indolines and anilines is reported.

Part 2: Efficient strategies for the construction of variably substituted bicyclo[5.3.1]undecenones (AB-taxane ring systems) and their conversion to tricyclo[9.3.1.03,8]pentadecenones (ABC taxane ring systems) and bicyclo[2.2.2]octanones

2004 ◽  
Vol 82 (2) ◽  
pp. 227-239 ◽  
Author(s):  
Nidia P Villalva-Servín ◽  
Alain Laurent ◽  
Alex G Fallis
Keyword(s):  
Lewis Acid ◽  
Sigmatropic Rearrangement ◽  
Diels Alder ◽  
Direct Access ◽  
Cope Rearrangement ◽  
Ring Closing Metathesis ◽  
Ring Systems ◽  
Sigmatropic Rearrangements ◽  
Key Words Magnesium ◽  
Cope Rearrangements

The extension of our strategies for the construction of cyclic molecules containing variably substituted bicyclo[5.3.1]undecenones (AB taxane ring systems) for the synthesis of the tricyclo[9.3.1.03,8]pentadecenone (ABC taxane ring system) and bicyclo[2.2.2]octanones are described. These routes employ a multi-component coupling protocol that employs sequential magnesium-mediated carbometallation of allyl-substituted propargyl alcohols followed by diastereoselective Lewis acid catalyzed intramolecular Diels–Alder reactions (IMDA). Subsequent ring-closing metathesis (RCM) afforded the ABC taxane core structure. Enone accelerated [3,3] sigmatropic rearrangements (Cope rearrangements) generated the bicyclo[2.2.2]octanone nucleus. In the presence of a Lewis acid, the dienophile precursor underwent a tandem reaction via the adduct directly to the bicyclo[2.2.2]octanones. This is the first example of a novel enone accelerated carbocycle Cope rearrangement and provides direct access to bicyclo[2.2.2]octanones by a new route that compliments the traditional cyclohexadiene cycloaddition approach. Key words: magnesium chelate, Lewis acid, taxanes, Diels–Alder, sigmatropic rearrangement, oxy-Cope, ring-closing metathesis, bicyclo[2.2.2]octanone.

ChemInform Abstract: Efficient Oxa-Diels-Alder/Semipinacol Rearrangement/Aldol Cascade Reaction: Short Approach to Polycyclic Architectures.

ChemInform ◽  
2015 ◽  
Vol 46 (28) ◽  
pp. no-no
Author(s):  
Jin-Bao Peng ◽  
Yue Qi ◽  
Ze-Ran Jing ◽  
Shao-Hua Wang ◽  
Yong-Qiang Tu ◽  
...  
Keyword(s):  
Cascade Reaction ◽  
Diels Alder ◽  
Semipinacol Rearrangement
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