Asymmetric Dearomatizative Diels-Alder Reaction for the Construction of Hydrodibenzo[b,d]furan Frameworks with Tetrasubstituted Stereogenic Centers

2017 ◽  
Vol 359 (6) ◽  
pp. 1018-1027 ◽  
Author(s):  
Ben-Xian Xiao ◽  
Wei Du ◽  
Ying-Chun Chen
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Stereogenic Centers

The Nakada Synthesis of (-)-FR182877

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Complex Mixture ◽  
Alder Reaction ◽  
Single Step ◽  
Diels Alder ◽  
Allylic Alcohol ◽  
Allylic Alcohols ◽  
Weinreb Amide ◽  
Diels Alder Reaction ◽  
Reaction Matrix ◽  
Stereogenic Centers

The Streptomyces metabolite (-)-FR182877 3 binds to and stabilizes microtubules, showing the same potency of anticancer activity as Taxol (paclitaxel). Masahisa Nakada of Waseda University assembled (Angew. Chem. Int. Ed. 2009, 48, 2580) the hexacyclic ring system of 3 by the tandem intramolecular Diels-Alder–intramolecular hetero Diels-Alder cyclization of 1, generating seven new stereogenic centers in a single step. The construction of the pentaene substrate 1 started with the known aldehyde 4, prepared by homologation of commercial ethyl 3-methyl-4-oxocrotonate. Addition of the propionyl oxazolidine anion 5 proceeded with high diastereocontrol, to give 6. The acyl oxazolidinone was not an efficient acylating agent, so it was converted to the Weinreb amide. Protection and deprotection then delivered the allylic acetate 7. The key step in the pentaene assembly was the carefully optimized Negishi-Wipf methylation of 8, followed by Pd-mediated coupling of the alkenyl organometallic so generated with the allylic acetate, to give 9. Condensation of the derived keto phosphonate 11 with the known aldehyde 12 then delivered the enone 13. The Nakada group has worked extensively on the intramolecular Diels-Alder reaction of substrates such as 1. They have shown that protected anti diols such as 1 cyclize with substantial diastereocontrol and in the desired sense. In contrast, cyclizations of protected syn diols proceed with poor diastereocontrol. The enone 13 was therefore reduced to the anti diol and protected, leading to 14 . Oxidation of 14 at room temperature led to a complex mixture, but slow oxidation at elevated temperature delivered 2 . Although the yield of 2 was not much better than if the reactions were carried out sequentially, first the intramolecular Diels-Alder cyclization, then the intramolecular hetero Diels-Alder cyclization, with the cascade protocol pure 2 was more readily separated from the reaction matrix. With 2 in hand, there was still the challenge of assembling the seven-membered ring. Cyclization was effected with an intramolecular Heck protocol. The two diastereomers of the allylic alcohol 15 cyclized with comparable efficiency. Ir-catalyzed alkene migration then converted the allylic alcohols to a mixture of ketones, which was equilibrated to give the more stable diasteromer.

scholarly journals Synthetic studies on clerodane diterpenoids. The total synthesis of (±)-2-oxo-5α,8α-13,14,15,16-tetranorclerod-3-en-12-oic acid

1997 ◽  
Vol 75 (6) ◽  
pp. 646-655 ◽  
Author(s):  
Hsing-Jang Liu ◽  
Kak-Shan Shia ◽  
Yongxin Han ◽  
Daqing Sun ◽  
Yu Wang
Keyword(s):  
Total Synthesis ◽  
Alder Reaction ◽  
Diels Alder ◽  
Synthetic Approach ◽  
Racemic Form ◽  
Diels Alder Reaction ◽  
Stereogenic Centers ◽  
The Face ◽  
Clerodane Diterpenoids ◽  
Synthetic Studies

A general synthetic approach to diterpenoids of the cis-clerodane family has been developed, leading to the first total synthesis, in racemic form, of 2-oxo-5α,8α-13,14,15,16-tetranorclerod-3-en-12-oic acid (2). The key operation involved is the face-selective Diels–Alder reaction of dienone ester 10 with trans-piperylene, giving rise to adduct 11 containing the decalin nucleus and correct stereogenic centers common to many cis-clerodane diterpenoids. Keywords: cis-clerodanes, general synthetic approach, total synthesis, face-selective Diels–Alder reaction.

ChemInform Abstract: Stereoselective Construction of Halogenated Quaternary Stereogenic Centers via Catalytic Asymmetric Diels-Alder Reaction.

ChemInform ◽  
2010 ◽  
Vol 41 (35) ◽  
pp. no-no
Author(s):  
Kazutaka Shibatomi ◽  
Kentaro Futatsugi ◽  
Fumito Kobayashi ◽  
Seiji Iwasa ◽  
Hisashi Yamamoto
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Stereogenic Centers ◽  
Catalytic Asymmetric ◽  
Quaternary Stereogenic Centers

scholarly journals Asymmetric Organocatalysis Revisited: Taming Hydrindanes with Jørgensen–Hayashi Catalyst

Synthesis ◽  
2018 ◽  
Vol 51 (05) ◽  
pp. 1123-1134 ◽  
Author(s):  
Yannick Stöckl ◽  
Wolfgang Frey ◽  
Johannes Lang ◽  
Birgit Claasen ◽  
Angelika Baro ◽  
...  
Keyword(s):  
Aldol Condensation ◽  
Alder Reaction ◽  
Diels Alder ◽  
Catalyst Loading ◽  
Diels Alder Reaction ◽  
Stereogenic Centers ◽  
Asymmetric Organocatalysis ◽  
Molecular Complexity ◽  
Low Catalyst Loading ◽  
High Degree

The organocatalytic Michael reaction of easily available 1-cyclopentene-1-carbaldehyde and 1,3-dicarbonyl compounds led to cyclopentanecarbaldehydes on a gram scale with low catalyst loading (2 mol%) and high enantioselectivity. The synthetic potential of 4-acylhexahydroindenones from intramolecular aldol condensation was demonstrated by Diels–Alder reaction to a tetracyclic derivative with seven stereogenic centers. The diastereofacial preference of the tetracyclic product was confirmed by DFT calculations. The described reaction sequence is characterized by few redox-economic steps and high degree of molecular complexity.

Stereoselective Construction of Halogenated Quaternary Stereogenic Centers via Catalytic Asymmetric Diels−Alder Reaction

2010 ◽  
Vol 132 (16) ◽  
pp. 5625-5627 ◽  
Author(s):  
Kazutaka Shibatomi ◽  
Kentaro Futatsugi ◽  
Fumito Kobayashi ◽  
Seiji Iwasa ◽  
Hisashi Yamamoto
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Stereogenic Centers ◽  
Catalytic Asymmetric ◽  
Quaternary Stereogenic Centers

The Diels-Alder Reaction of 2-Ethenyl-1,4-Benzodioxin: A New and Simple Synthesis of Bisaryl Ethers

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

The intermolecular anthracene-transfer in a regiospecific antipodal C60 difunctionalization

2020 ◽  
Author(s):  
Radu Talmazan ◽  
Klaus R. Liedl ◽  
Bernhard Kräutler ◽  
Maren Podewitz
Keyword(s):  
Noncovalent Interactions ◽  
Interaction Model ◽  
Alder Reaction ◽  
Diels Alder ◽  
Stacking Interactions ◽  
Pi Stacking ◽  
Diels Alder Reaction ◽  
Double Decker ◽  
Anthracene Molecule ◽  
New Strategies

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>

Natural Products Biosynthesis Involving a Putative Diels-Alder Reaction

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