A Chemoenzymatic and Enantioselective Route to the Tricyclic Frameworks Associated with the Protoilludane and Marasmane Classes of Sesquiterpene

2004 ◽  
Vol 57 (9) ◽  
pp. 895 ◽  
Author(s):  
Martin G. Banwell ◽  
Gwion J. Harfoot
Keyword(s):  
Natural Products ◽  
Benzene Solution ◽  
Cycloaddition Reaction ◽  
Diels Alder ◽  
Enantiomerically Pure ◽  
Direct Irradiation ◽  
Tricyclic Ketone

The enantiomerically pure cis-1,2-dihydrocatechol 3, which is obtained in quantity by microbial dihydroxylation of toluene, has been converted over ten steps, including an initial Diels–Alder cycloaddition reaction, into the tricyclic ketone 12. Direct irradiation of a benzene solution of the latter compound affords a mixture of compounds 13 and 14 which embody the tricyclic frameworks of the sesquiterpene natural products tsugicoline A (1) and isovelleral (2), respectively.

Chemoenzymatic methods for the enantioselective preparation of sesquiterpenoid natural products from aromatic precursors

2003 ◽  
Vol 75 (2-3) ◽  
pp. 223-229 ◽  
Author(s):  
M. G. Banwell ◽  
A. J. Edwards ◽  
G. J. Harfoot ◽  
K. A. Jolliffe ◽  
M. D. McLeod ◽  
...  
Keyword(s):  
Natural Products ◽  
Diels Alder ◽  
Cycloaddition Reactions ◽  
Enantiomerically Pure

The enantiomerically pure cis-1,2-dihydrocatechols 2, which are generated by enzymatic dihydroxylation of the corresponding aromatic, engage in regio- and stereo-controlled Diels-Alder cycloaddition reactions to give a range of synthetically useful bicyclo[2.2.2]octenes. Certain examples of the latter type of compound have been used as starting materials in the synthesis of the sesquiterpenoids (−)-patchoulenone and (−)-hirsutene.

Pigments of Fungi. LIX. Synthesis of (1S,3S)- and (1R,3R)-Austrocortilutein and (1S,3S)-Austrocortirubin from Citramalic Acid

2000 ◽  
Vol 53 (4) ◽  
pp. 245 ◽  
Author(s):  
Melvyn Gill ◽  
Michael F. Harte ◽  
Abilio Ten
Keyword(s):  
Natural Products ◽  
Diels Alder ◽  
Pure Form ◽  
Enantiomerically Pure ◽  
Naturally Occurring ◽  
First Time

The naturally occurring tetrahydroanthraquinone (1S,3S)-austrocortilutein (1) is synthesized for the first time in enantiomerically pure form by Diels–Alder cycloaddition between the functionalized butadiene derivative (8) and the chiral 1,3-dihydroxy-1,2,3,4-tetrahydro-5,8-naphthoquinone (9), the latter being derived from (R)-citramalic acid (3). The natural products (1S,3S)-austrocortirubin (2) and (1R,3R)-austrocortilutein (5) were also prepared for the first time by using the same strategy.

A Chemoenzymatic Synthesis of the cis-Decalin Core Associated with the Novel Anti-Mitotic Agent Phomopsidin: Some Observations Concerning a High-Pressure-Promoted Diels–Alder Cycloaddition Reaction of (1S,2R)-3-Methyl-cis-1,2-dihydrocatechol and the Anionic Oxy–Cope Rearrangement of Compounds Derived from the Adduct

2004 ◽  
Vol 57 (7) ◽  
pp. 641 ◽  
Author(s):  
Martin G. Banwell ◽  
Alison J. Edwards ◽  
Malcolm D. McLeod ◽  
Scott G. Stewart
Keyword(s):  
Cycloaddition Reaction ◽  
Diels Alder ◽  
Chemoenzymatic Synthesis ◽  
Cope Rearrangement ◽  
The Novel ◽  
X Ray Diffraction ◽  
Enantiomerically Pure ◽  
X Ray ◽  
Wittig Rearrangements ◽  
Rearrangement Reaction

The enantiomerically pure and enzymatically derived cis-1,2-dihydrocatechol 2 engages in a diastereofacially selective Diels–Alder cycloaddition reaction with commercially available lactone 3 at 19 kbar to afford adduct 4, which is readily elaborated to the diene-ol 13. Treatment of this last compound with KH/18[crown]-6 resulted in successive anionic oxy-Cope and 1,2-Wittig rearrangements to afford acyloin 14 embodying the cis-decalin core associated with the natural product phomopsidin (1). Compound 16 also engages in an anionic oxy-Cope rearrangement reaction to give, depending on the molar equivalents of base used, either the cis-decalin 17 or the hexahydroindene 18. The structure of compound 18 has been established by single-crystal X-ray diffraction analysis.

Competitive Intramolecular Diels - Alder Reactions of bis-α,β-Unsaturated Ester Derivatives of Enzymatically Derived and Enantiopure cis-1,2-Dihydrocatechols. Enantiodivergent Synthesis of Monochiral Bicyclo[2.2.2]oct-2-enes

2003 ◽  
Vol 56 (9) ◽  
pp. 861 ◽  
Author(s):  
Martin G. Banwell ◽  
Cai Chun ◽  
Alison J. Edwards ◽  
Markus M. Vögtle
Keyword(s):  
Natural Products ◽  
Single Crystal ◽  
Building Blocks ◽  
Diels Alder ◽  
Unsaturated Ester ◽  
Enantiomerically Pure ◽  
X Ray ◽  
Derivatives Of ◽  
Natural Products Synthesis

bis-Crotonate and related α,β-unsaturated ester derivatives of readily available and enantiomerically pure cis-1,2-dihydrocatechols engage, upon heating in refluxing toluene, in two competitive intramolecular Diels–Alder reactions to give varying mixtures of chromatographically separable and pseudo-enantiomeric bicyclo[2.2.2]oct-2-enes. Such adducts, many of which have been characterized by single-crystal X-ray analysis, are likely to serve as useful building blocks in natural products synthesis.

Development of the Claisen Rearrangement/Organocatalytic Diels-Alder Approach for the Synthesis of Eunicellins

2014 ◽  
Vol 67 (9) ◽  
pp. 1189 ◽  
Author(s):  
Joel F. Hooper ◽  
Jonathan M. White ◽  
Andrew B. Holmes
Keyword(s):  
Natural Products ◽  
Claisen Rearrangement ◽  
Cycloaddition Reaction ◽  
Diels Alder ◽  
Powerful Method ◽  
Medium Ring

The intramolecular Diels-Alder approach to synthesizing eunicellins has proved to be a powerful method for the synthesis of this class of natural products. The key to the success of this strategy is control over the endo/exo selectivity of the cycloaddition reaction, which we have addressed through an organocatalytic reaction employing the MacMillan imidazolidinone catalyst. This approach has been further developed to address the issue of functionality at the C8 position, and a novel scalable method for the extension of the medium-ring lactone has been developed.

scholarly journals The Chemoenzymatic Total Synthesis of Phellodonic Acid, a Biologically Active and Highly Functionalized Hirsutane Derivative Isolated from the Tasmanian Fungus Phellodon melaleucus

2008 ◽  
Vol 61 (2) ◽  
pp. 94 ◽  
Author(s):  
Tristan A. Reekie ◽  
Kerrie A. B. Austin ◽  
Martin G. Banwell ◽  
Anthony C. Willis
Keyword(s):  
Total Synthesis ◽  
Cycloaddition Reaction ◽  
Genetically Engineered ◽  
Diels Alder ◽  
Biologically Active ◽  
Enantiomerically Pure ◽  
Toluene Dioxygenase ◽  
E Coli ◽  
Whole Cell Biotransformation ◽  
Genetically Engineered Microorganism

A total synthesis of the title natural product, 1, has been achieved using the cis-1,2-dihydrocatechol 7 as starting material. Compound 7 is readily obtained in large quantity and in an enantiomerically pure form through the whole-cell biotransformation of toluene using the genetically engineered microorganism E. coli JM109 (pDTG601) that overexpresses the enzyme toluene dioxygenase (TDO). Three key chemical steps were employed in the synthesis, the first of which was the microwave-promoted Diels–Alder cycloaddition reaction between diene 8 and cyclopent-1-en-2-one to give adduct 9. The second key step was the photochemically promoted oxa-di-π-methane rearrangement of the bicyclo[2.2.2]octenone derivative 15 of 9 to give the epimers 16 and 17, and the third key step was the reductive cleavage of the last pair of compounds so as to afford the linear triquinane 19. Elaboration of compound 19 to target 1 followed established procedures. Single-crystal X-ray analyses were carried out on compounds 11 and 19.

scholarly journals Recent applications of intramolecular Diels–Alder reaction in total synthesis of natural products

RSC Advances ◽  
2015 ◽  
Vol 5 (63) ◽  
pp. 50890-50912 ◽  
Author(s):  
Majid M. Heravi ◽  
Vaezeh Fathi Vavsari
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Organic Synthesis ◽  
Cycloaddition Reaction ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction

Diels–Alder (D–A) reaction is undoubtedly the most powerful [4 + 2] cycloaddition reaction in organic synthesis.

Biomimetic Synthesis of Hyperjapones F-I

2018 ◽  
Vol 71 (9) ◽  
pp. 649 ◽  
Author(s):  
Hiu C. Lam ◽  
Quang D. Phan ◽  
Christopher J. Sumby ◽  
Jonathan H. George
Keyword(s):  
Natural Products ◽  
Building Blocks ◽  
Diels Alder ◽  
Biomimetic Synthesis ◽  
Enantiomerically Pure ◽  
Biosynthetic Precursor ◽  
Hypericum Japonicum ◽  
Optical Rotations

Hyperjapones F–I are tetracyclic meroterpenoids recently isolated from Hypericum japonicum. All four of these natural products have been synthesised using oxidative, intermolecular hetero-Diels–Alder reactions to couple their common biosynthetic precursor, norflavesone, to the appropriate monoterpene building blocks: sabinene, β-pinene, and α-pinene. The synthesis of enantiomerically pure hyperjapones H and I and comparison of their optical rotations to those of the natural samples indicated that these meroterpenoids are probably biosynthesised as either racemic or scalemic mixtures.

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

Enantioselective Syntheses of Flavonoid Diels-Alder Natural Products: A Review

2018 ◽  
Vol 15 (2) ◽  
pp. 221-229 ◽  
Author(s):  
Shah Bakhtiar Nasir ◽  
Noorsaadah Abd Rahman ◽  
Chin Fei Chee
Keyword(s):  
Natural Products ◽  
Organic Synthesis ◽  
Lewis Acid ◽  
Alder Reaction ◽  
Diels Alder ◽  
Enantioselective Synthesis ◽  
Chiral Ligand ◽  
Asymmetric Syntheses ◽  
Diels Alder Reaction ◽  
Enantioselective Syntheses

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.

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