ChemInform Abstract: Stereoselective Ring Expansion of Vinyl Oxiranes: Mechanistic Insights and Natural Product Total Synthesis.

ChemInform ◽  
2010 ◽  
Vol 41 (27) ◽  
pp. no-no
Author(s):  
Matthew Brichacek ◽  
Lindsay A. Batory ◽  
Jon T. Njardarson
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Ring Expansion

scholarly journals Synthesis of Highly Functionalised Furo[3,4-b]pyrans: Towards the Fungal Metabolite (−)-TAN-2483B

2021 ◽  
Author(s):  
◽  
R.M. Kalpani K. Somarathne
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Natural Product ◽  
Cyclopropane Ring ◽  
Ring Expansion ◽  
Ethyl Esters ◽  
Pyran Ring ◽  
Synthetic Strategy ◽  
Alternative Approach ◽  
Synthetic Approaches

<p>Carbohydrate-derived cyclopropanes combine both the stereochemical wealth of carbohydrates and the reactivity of cyclopropanes. A diverse variety of reaction modes for these cyclopropyl carbohydrates can be harnessed for the synthesis of natural products and other targets.  The natural products (−)-TAN-2483A and (−)-TAN-2483B are fungal secondary metabolites displaying a variety of bioactivities such as inhibition of c-src kinase action and parathyroid hormone-induced bone resorption. This thesis described several synthetic approaches to the natural product (−)-TAN-2483B and analogues of (−)-TAN-2483B employing cyclopropane ring expansion.  The synthetic route to (−)-TAN-2483B began with the readily available substrate D-mannose. The pyran ring unsaturation of the natural product was established by a cyclopropanation-ring expansion sequence. A synthetic strategy via dichlorocyclopropane-based intermediates is described in chapter 2. This being unsuccessful, an alternative approach via 2-fomyl-glycal was developed in chapter 3. The chapter 2 and 3 provided a solid background for the achievement of the analogues synthesis illustrated in chapter 4 via dibromocyclopropane. Lewis acid-mediated alkynylation followed by Pdcatalysed carbonylative lactonisation was successfully utilised in the revelation of the furo[3,4-b]pyran ring skeleton. This route afforded analogues of TAN-2483B; the Z-and E-unsaturated ethyl esters 140 and 141 and hydroxy(−)-TAN-2483B 145. The total synthesis of (−)-TAN-2483B was not achieved due to unforeseen obstacles encountered in the deoxygenation of the side arm of 335 (Chapter 4) into the E-propenyl side arm of (−)-TAN-2483B.</p>

scholarly journals A Concise Total Synthesis of (±)-Vibralactone

2018 ◽  
Author(s):  
Sepand Nistanaki ◽  
Luke A. Boralsky ◽  
Roy D. Pan ◽  
Hosea Nelson
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Early Stage ◽  
Ring Expansion ◽  
Biologically Active ◽  
Valence Isomerization ◽  
Reduction Strategy ◽  
Quaternary Stereocenter

Disclosed is a four-step synthesis of (<i>±</i>)-vibralactone, a biologically active terpenoid natural product. A key photochemical valence isomerization of 3-prenyl-pyran-2-one forges both the all-carbon quaternary stereocenter and the β-lactone at an early stage. Cyclopropanation of the resulting bicyclic β-lactone furnishes a strained housane structure that is converted to the natural product through a sequential ring expansion and reduction strategy. Our concise and modular route to the natural product provides the shortest total synthesis of (<i>±</i>)-vibralactone reported to date. <br>

Stereoselective Ring Expansion of Vinyl Oxiranes: Mechanistic Insights and Natural Product Total Synthesis

2010 ◽  
Vol 49 (9) ◽  
pp. 1648-1651 ◽  
Author(s):  
Matthew Brichacek ◽  
Lindsay A. Batory ◽  
Jon T. Njardarson
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Ring Expansion

Stereoselective Ring Expansion of Vinyl Oxiranes: Mechanistic Insights and Natural Product Total Synthesis

2010 ◽  
Vol 122 (9) ◽  
pp. 1692-1695 ◽  
Author(s):  
Matthew Brichacek ◽  
Lindsay A. Batory ◽  
Jon T. Njardarson
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Ring Expansion

scholarly journals A Concise Total Synthesis of (±)-Vibralactone

2018 ◽  
Author(s):  
Sepand Nistanaki ◽  
Luke A. Boralsky ◽  
Roy D. Pan ◽  
Hosea Nelson
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Early Stage ◽  
Ring Expansion ◽  
Biologically Active ◽  
Valence Isomerization ◽  
Reduction Strategy ◽  
Quaternary Stereocenter

Disclosed is a four-step synthesis of (<i>±</i>)-vibralactone, a biologically active terpenoid natural product. A key photochemical valence isomerization of 3-prenyl-pyran-2-one forges both the all-carbon quaternary stereocenter and the β-lactone at an early stage. Cyclopropanation of the resulting bicyclic β-lactone furnishes a strained housane structure that is converted to the natural product through a sequential ring expansion and reduction strategy. Our concise and modular route to the natural product provides the shortest total synthesis of (<i>±</i>)-vibralactone reported to date. <br>

scholarly journals A Concise Total Synthesis of (±)-Vibralactone

2018 ◽  
Author(s):  
Sepand Nistanaki ◽  
Luke A. Boralsky ◽  
Roy D. Pan ◽  
Hosea Nelson
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Early Stage ◽  
Ring Expansion ◽  
Biologically Active ◽  
Valence Isomerization ◽  
Reduction Strategy ◽  
Quaternary Stereocenter

Disclosed is a four-step synthesis of (<i>±</i>)-vibralactone, a biologically active terpenoid natural product. A key photochemical valence isomerization of 3-prenyl-pyran-2-one forges both the all-carbon quaternary stereocenter and the β-lactone at an early stage. Cyclopropanation of the resulting bicyclic β-lactone furnishes a strained housane structure that is converted to the natural product through a sequential ring expansion and reduction strategy. Our concise and modular route to the natural product provides the shortest total synthesis of (<i>±</i>)-vibralactone reported to date. <br>

scholarly journals Synthesis of Highly Functionalised Furo[3,4-b]pyrans: Towards the Fungal Metabolite (−)-TAN-2483B

2021 ◽  
Author(s):  
◽  
R.M. Kalpani K. Somarathne
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Natural Product ◽  
Cyclopropane Ring ◽  
Ring Expansion ◽  
Ethyl Esters ◽  
Pyran Ring ◽  
Synthetic Strategy ◽  
Alternative Approach ◽  
Synthetic Approaches

<p>Carbohydrate-derived cyclopropanes combine both the stereochemical wealth of carbohydrates and the reactivity of cyclopropanes. A diverse variety of reaction modes for these cyclopropyl carbohydrates can be harnessed for the synthesis of natural products and other targets.  The natural products (−)-TAN-2483A and (−)-TAN-2483B are fungal secondary metabolites displaying a variety of bioactivities such as inhibition of c-src kinase action and parathyroid hormone-induced bone resorption. This thesis described several synthetic approaches to the natural product (−)-TAN-2483B and analogues of (−)-TAN-2483B employing cyclopropane ring expansion.  The synthetic route to (−)-TAN-2483B began with the readily available substrate D-mannose. The pyran ring unsaturation of the natural product was established by a cyclopropanation-ring expansion sequence. A synthetic strategy via dichlorocyclopropane-based intermediates is described in chapter 2. This being unsuccessful, an alternative approach via 2-fomyl-glycal was developed in chapter 3. The chapter 2 and 3 provided a solid background for the achievement of the analogues synthesis illustrated in chapter 4 via dibromocyclopropane. Lewis acid-mediated alkynylation followed by Pdcatalysed carbonylative lactonisation was successfully utilised in the revelation of the furo[3,4-b]pyran ring skeleton. This route afforded analogues of TAN-2483B; the Z-and E-unsaturated ethyl esters 140 and 141 and hydroxy(−)-TAN-2483B 145. The total synthesis of (−)-TAN-2483B was not achieved due to unforeseen obstacles encountered in the deoxygenation of the side arm of 335 (Chapter 4) into the E-propenyl side arm of (−)-TAN-2483B.</p>

Progress Toward The Total Synthesis Of The Marine Natural Product Karlotoxin 5

Planta Medica ◽  
2013 ◽  
Vol 79 (10) ◽  
Author(s):  
M Albadry ◽  
Y Zou ◽  
Y Takahashi ◽  
A Waters ◽  
M Hossein ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Marine Natural Product

Total Synthesis of the Antitumor Depsipeptide FE399 and its S-Benzyl Derivative: A Macrolactamization Approach

2020 ◽  
Author(s):  
Takayuki Tonoi ◽  
Miyuki Ikeda ◽  
Teruyuki Sato ◽  
Ryo Kawahara ◽  
Takatsugu Murata ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Total Synthesis ◽  
Natural Product ◽  
Condensation Reaction ◽  
Practical Method ◽  
Equilibrium Mixture ◽  
Conformational Isomers ◽  
Single Isomer

<div>An efficient and practical method for the synthesis of (9R,14R,17R)-FE399, a novel antitumor bicyclic depsipeptide, was developed. A 2-methyl-6-nitrobenzoic anhydride (MNBA)-mediated dehydration condensation reaction was effectively employed for the formation of the 16-membered macrocyclic depsipeptide moiety of FE399. FE399 was found to exist as an inseparable equilibrium mixture of conformational isomers; the mixture was quantitatively transformed into the corresponding S-benzyl product and isolated as a single isomer. Thus, we could confirm that the molecular structure of FE399 obtained by this method is identical to that of the natural product.</div>

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