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.

Pigments of Fungi. LXIII. Synthesis of (1S,3R)- and (1R,3S)-Austrocortilutein and the Enantiomeric Purity of Austrocortilutein in some Australian Dermocybe Toadstools

2000 ◽  
Vol 53 (1) ◽  
pp. 41 ◽  
Author(s):  
Catherine Elsworth ◽  
Melvyn Gill ◽  
Evelin Raudies ◽  
Abilio Ten
Keyword(s):  
Stationary Phase ◽  
Chiral Stationary Phase ◽  
Enantiomeric Purity ◽  
Diels Alder ◽  
Pure Form ◽  
Enantiomerically Pure ◽  
Naturally Occurring ◽  
First Time

The naturally occurring tetrahydroanthraquinones (1S,3R)- and (1R,3S)-austrocortilutein (1b) and (1d), respectively, are synthesized for the first time in enantiomerically pure form by Diels–Alder cycloaddition between the functionalized butadiene derivative (4) and the corresponding monochiral trans-1,3-dihydroxy-1,2,3,4- tetrahydro-5,8-naphthoquinone (5a) or (5b), themselves derived from citramalic acid. Separation of the four stereoisomeric austrocortiluteins by using h.p.l.c. over a chiral stationary phase reveals that the enantiomeric purity of the (1S,3S)- and (1R,3R)-quinones (1a) and (1c) varies from species to species whereas the (1S,3R)-isomer (1b) is, in the five cases examined, enantiomerically pure.

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.

Naturally occurring organoiodines

RSC Advances ◽  
2014 ◽  
Vol 4 (101) ◽  
pp. 57350-57376 ◽  
Author(s):  
Lishu Wang ◽  
Xuefeng Zhou ◽  
Mangaladoss Fredimoses ◽  
Shengrong Liao ◽  
Yonghong Liu
Keyword(s):  
Natural Products ◽  
The Past ◽  
Naturally Occurring ◽  
First Time

This review, with 290 references, presents the fascinating area of iodinated natural products over the past hundred years for the first time.

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.

scholarly journals Thiourea-catalyzed Diels–Alder reaction of a naphthoquinone monoketal dienophile

2013 ◽  
Vol 9 ◽  
pp. 1414-1418 ◽  
Author(s):  
Carsten S Kramer ◽  
Stefan Bräse
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Alder Reaction ◽  
Diels Alder ◽  
Selective Synthesis ◽  
Quaternary Center ◽  
Diels Alder Reaction ◽  
Cycloaddition Product ◽  
Sterically Hindered ◽  
First Time

A variety of organocatalysts were screened for the catalysis of the naphthoquinone monoketal Diels–Alder reaction. In this study we found that Schreiner's thiourea catalyst 10 and Jacobson's thiourea catalyst 12 facilitate the cycloaddition of the sterically hindered naphthoquinone monoketal dienophile 3 with diene 4. The use of thiourea catalysis allowed for the first time the highly selective synthesis of the exo-product 2a in up to 63% yield. In this reaction a new quaternary center was built. The so formed cycloaddition product 2a represents the ABC tricycle of beticolin 0 (1) and is also a valuable model substrate for the total synthesis of related natural products.

scholarly journals Bisindole Alkaloids from a New Zealand Deep-Sea Marine Sponge Lamellomorpha strongylata

Marine Drugs ◽  
2019 ◽  
Vol 17 (12) ◽  
pp. 683 ◽  
Author(s):  
Kavita Ragini ◽  
Andrew M. Piggott ◽  
Peter Karuso
Keyword(s):  
Natural Products ◽  
New Zealand ◽  
Secondary Metabolites ◽  
Marine Sponge ◽  
Deep Sea ◽  
Indole Alkaloids ◽  
Chemical Investigation ◽  
Enantiomerically Pure ◽  
The One ◽  
First Time

Chemical investigation of the secondary metabolites of a rare New Zealand deep-sea sponge, Lamellomorpha strongylata, resulted in the isolation of twenty-one indole alkaloids, including two new bisindoles—(Z)-coscinamide D (1), (E)-coscinamide D (2)—and four compounds isolated for the first time as natural products—lamellomorphamides A (3), B (4), C (5) and D (6). In addition, fifteen previously reported natural products were isolated, seven of which are seco analogs of hamacanthin alkaloids. The one sponge produces enantiomerically pure but opposite configurations of compounds that only differ in the number of bromines, suggesting enantiodivergent biosynthesis. In addition, four compounds were isolated as partial racemates, suggesting these compounds are biosynthesized via two independent routes.

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.

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.

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