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 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 Stereoselective total syntheses of (±)-sinularene and (±)-5-epi-sinularene: a general intramolecular Diels–Alder approach to tricyclic sesquiterpenes

1985 ◽  
Vol 63 (4) ◽  
pp. 993-995 ◽  
Author(s):  
Kazimierz Antczak ◽  
John F. Kingston ◽  
Alex G. Fallis
Keyword(s):  
Double Bond ◽  
Methyl Ester ◽  
Total Synthesis ◽  
Ring System ◽  
Diels Alder ◽  
Exocyclic Double Bond ◽  
Total Syntheses ◽  
Methyl Group ◽  
Secondary Hydroxyl ◽  
Selective Hydrogenolysis

Stereoselective total synthesis of (±)-sinularene and (±)-5-epi-sinularene are described. The sequence employs a "blocked" cyclopentadiene in which the cyclopropane unit also serves as a latent methyl group. Thus intramolecular [4 + 2] cycloaddition of the substituted methyl spiro[2.4]hepta-4,6-dien-1-yl)-2-pentenoate 11 affords 5-benzyloxy-6-isopropyl-8-carbomethoxytetracyclo[5.4.01,7.02,4.02,9]undec-10-ene (12) which after selective hydrogenolysis generates the tricyclo[4.4.01,6.02,8]decane (sinularene) ring system. Removal of the secondary hydroxyl function (Ph3P/CCl4/CH3CN; H2/Pd/C), reduction of the methyl ester (LiAlH4), and introduction of the exocyclic double bond (acetate pyrolysis, 550 °C) completes the synthesis of (±)-sinularene in 14 steps from cyclopentadiene. A parallel series of reactions employing the isopropyl epimer of 12 affords (±)-5-epi-sinularene.

A Thio-Diels−Alder Route to the Azocine Ring System. Total Synthesis of (±)-Otonecine

1998 ◽  
Vol 120 (15) ◽  
pp. 3613-3622 ◽  
Author(s):  
Edwin Vedejs ◽  
Rocco J. Galante ◽  
Peter G. Goekjian
Keyword(s):  
Total Synthesis ◽  
Ring System ◽  
Diels Alder

Recent results toward the stereoselective synthesis of biologically active natural products

2007 ◽  
Vol 79 (2) ◽  
pp. 163-172 ◽  
Author(s):  
Luiz C. Dias ◽  
Luciana G. de Oliveira ◽  
Paulo R. R. Meira
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Cell Cultures ◽  
Stereoselective Synthesis ◽  
Animal Cell ◽  
Biologically Active ◽  
Asymmetric Total Synthesis ◽  
Callystatin A ◽  
Animal Cell Cultures ◽  
Active Natural

This paper describes the convergent and stereocontrolled asymmetric total synthesis of (+)-crocacins C and D, potent inhibitors of animal cell cultures and several yeasts and fungi, and (-)-callystatin A, a potent antitumor polyketide.

Diversity-Oriented Synthesis of Natural Products via Gold-Catalyzed Cascade Reactions

Synlett ◽  
2018 ◽  
Vol 29 (12) ◽  
pp. 1552-1571 ◽  
Author(s):  
Jianxian Gong ◽  
Zhen Yang ◽  
Yueqing Gu ◽  
Ceheng Tan
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Cascade Reactions ◽  
Cascade Reaction ◽  
Biologically Active ◽  
Synthetic Methods ◽  
Left Wing ◽  
Asymmetric Total Synthesis ◽  
Diversity Oriented Synthesis ◽  
Active Natural

This account describes our group’s latest research in the field of diversity-oriented synthesis of natural products via gold-catalyzed cascade reactions. We present two general strategies based on gold-catalyzed cycloisomerization: a gold-catalyzed cascade reaction of 1,7-diynes and a pinacol-terminated gold-catalyzed cascade reaction. We highlight our development of synthetic methods for the construction of biologically active natural products by using these two strategies.1 Introduction2 Gold-Catalyzed Cascade Reactions of 1,7-Diynes2.1 Collective Synthesis of C15 Oxygenated Drimane-Type Sesquiterpenoids2.2 Synthesis of Left-Wing Fragment of Azadirachtin I2.3 Collective Synthesis of Cladiellins3 Pinacol-Terminated Gold-Catalyzed Cascade Reaction3.1 Asymmetric Formal Total Synthesis of (+)-Cortistatins3.2 Total Synthesis of Orientalol F3.3 Asymmetric Total Synthesis of (–)-Farnesiferol C4 Summary and Outlook

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