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.

Taxane Diterpene Synthesis Studies. Part 2: Towards Taxinine—Enantiospecific Construction of an AB-ring Substructure Incorporating both Quaternary Carbon Centres and Attempts to Annulate the C-ring

2004 ◽  
Vol 57 (1) ◽  
pp. 53 ◽  
Author(s):  
Martin G. Banwell ◽  
Malcolm D. McLeod ◽  
Andrew G. Riches
Keyword(s):  
Total Synthesis ◽  
Cycloaddition Reaction ◽  
Ring System ◽  
Diels Alder ◽  
Biologically Active ◽  
Allylic Oxidation ◽  
Cope Rearrangement ◽  
Rearrangement Reaction ◽  
Ab Ring ◽  
Active Natural

In connection with efforts to develop an efficient total synthesis of the biologically active natural product taxinine 1, the enzymatically-derived and monochiral cis-1,2-dihydrocatechol 7 was converted, over several steps including a Diels–Alder cycloaddition reaction, into the bicyclo[2.2.2]octan-2-one 18. Reaction of the last compound with the organocerium reagent 22 afforded the 1,5-diene 23 which engaged in an anionic oxy-Cope rearrangement reaction to give, after C-methylation of the product enolate 25, bicyclo[5.3.1]undecenone 27 embodying the AB-ring system of target 1. Two methods for allylic oxidation of such products were developed and several unsuccessful attempts to effect a cyclization reaction so as to establish the taxane C-ring are described.

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.

scholarly journals A Versatile, Diels–Alder Reaction-Based Approach to Prenyleudesmane Diterpenoids: A Concise Total Synthesis of Sinupol

Synlett ◽  
2020 ◽  
Vol 31 (10) ◽  
pp. 1007-1010
Author(s):  
Koichiro Ota ◽  
Hiroaki Miyaoka ◽  
Kazuo Kamaike
Keyword(s):  
Total Synthesis ◽  
Asymmetric Synthesis ◽  
Alder Reaction ◽  
Diels Alder ◽  
Biologically Active ◽  
Diels Alder Reaction ◽  
Step Procedure

Herein, a concise strategy designed to provide general and diversifiable access to various prenyleudesmane terpenoids is described and utilized in the asymmetric synthesis of a biologically active prenyleudesmane diterpenoid, sinupol, which is accomplished in a seven-step procedure.

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.

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 total synthesis of ent-neopinone and formal total synthesis of ent-codeinone from β-bromoethylbenzene*

2011 ◽  
Vol 89 (6) ◽  
pp. 709-729 ◽  
Author(s):  
Jan Duchek ◽  
T. Graeme Piercy ◽  
Jacqueline Gilmet ◽  
Tomas Hudlicky
Keyword(s):  
Total Synthesis ◽  
Heck Reaction ◽  
Aldol Condensation ◽  
Side Chain ◽  
Prins Reaction ◽  
Toluene Dioxygenase ◽  
E Coli ◽  
Key Steps ◽  
New Compounds ◽  
Stereogenic Center

Formal total synthesis of ent-codeinone and ent-codeine was accomplished via the total synthesis of ent-neopinone attained in 14 steps from β-bromoethylbenzene. The key steps included (i) enzymatic dihydroxylation of β-bromoethylbenzene with E. coli JM109 (pDTG601a), an organism that overexpresses toluene dioxygenase, (ii) a Heck reaction to establish C-13 stereogenic center, (iii) aldol condensation, and (iv) 1,6-conjugate addition of the ethylamino side chain to C-9. Several other modes of construction of the C-9 and C-14 centers were also investigated: Mannich cyclization, and aza-Prins reaction. The synthesis of ent-codeinone was formalized by intersecting Fukuyama’s recently published approach. Experimental and spectral data are provided for all new compounds.

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