scholarly journals Bioinspired Divergent Oxidative Cyclization from Strictosidine and Vincoside Derivatives: Second‐Generation Total Synthesis of (−)‐Cymoside and Access to an Original Hexacyclic‐Fused Furo[3,2‐ b ]indoline

2020 ◽  
Vol 26 (71) ◽  
pp. 17190-17194
Author(s):  
Yingchao Dou ◽  
Cyrille Kouklovsky ◽  
Guillaume Vincent
Keyword(s):  
Total Synthesis ◽  
Second Generation ◽  
Oxidative Cyclization

Synthesis of (+)-bovidic acid

2015 ◽  
Vol 93 (2) ◽  
pp. 196-198 ◽  
Author(s):  
Geoffrey A. Phillips ◽  
Timothy B. Wright ◽  
Andrew C. Stevens ◽  
Brian L. Pagenkopf
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Second Generation ◽  
Oxidative Cyclization ◽  
The Core ◽  
Insect Repellant

(+)-Bovidic acid is an 18-carbon hydroxyfuranoid acid isolated from the pelage of the gaur (Bos frontalis) and displays potential as an insect repellant. Both a formal and total synthesis of (+)-bovidic acid was carried out with the core of the natural product being synthesized through Mukaiyama aerobic oxidative cyclization employing the second-generation Co(nmp)2 catalyst.

scholarly journals Bioinspired Divergent Oxidative Cyclization of Strictosidine and Vincoside Derivatives: Second Generation Enantioselective Total Synthesis of (–)-Cymoside

2020 ◽  
Author(s):  
Yingchao Dou ◽  
Cyrille Kouklovsky ◽  
Guillaume Vincent
Keyword(s):  
Total Synthesis ◽  
Second Generation ◽  
Oxidative Cyclization ◽  
Enol Ether ◽  
Enantioselective Total Synthesis ◽  
Terminal Alkene

<p>We report our second generation synthesis of (–)-cymoside as well as the formation of a new hexacyclic-fused furo[3,2-<i>b</i>]indoline framework. After a Pictet-Spengler condensation between secologanin tetraacetate and tryptamine, the course of the cyclization of the 7-hydroxyindolenine intermediate generated by oxidation with an oxaziridine, depends on the stereochemistry of the 3-position. The 3<i>-(S)-</i>strictosidine stereochemistry delivered efficiently the scaffold of cymoside via intramolecular coupling with the C16-C17 enol ether, while the 3<i>-(R)-</i>vincoside stereochemistry directed towards the reaction with the C18-C19 terminal alkene and the formation of the unexpected caged compound.</p>

scholarly journals Bioinspired Divergent Oxidative Cyclization of Strictosidine and Vincoside Derivatives: Second Generation Enantioselective Total Synthesis of (–)-Cymoside

2020 ◽  
Author(s):  
Yingchao Dou ◽  
Cyrille Kouklovsky ◽  
Guillaume Vincent
Keyword(s):  
Total Synthesis ◽  
Second Generation ◽  
Oxidative Cyclization ◽  
Enol Ether ◽  
Enantioselective Total Synthesis ◽  
Terminal Alkene

<p>We report our second generation synthesis of (–)-cymoside as well as the formation of a new hexacyclic-fused furo[3,2-<i>b</i>]indoline framework. After a Pictet-Spengler condensation between secologanin tetraacetate and tryptamine, the course of the cyclization of the 7-hydroxyindolenine intermediate generated by oxidation with an oxaziridine, depends on the stereochemistry of the 3-position. The 3<i>-(S)-</i>strictosidine stereochemistry delivered efficiently the scaffold of cymoside via intramolecular coupling with the C16-C17 enol ether, while the 3<i>-(R)-</i>vincoside stereochemistry directed towards the reaction with the C18-C19 terminal alkene and the formation of the unexpected caged compound.</p>

scholarly journals Total syntheses of all tri-oxygenated 16-phytoprostane classes via a common precursor constructed by oxidative cyclization and alkyl–alkyl coupling reactions as the key steps

2017 ◽  
Vol 15 (44) ◽  
pp. 9408-9414 ◽  
Author(s):  
Jakub Smrček ◽  
Radek Pohl ◽  
Ullrich Jahn
Keyword(s):  
Total Synthesis ◽  
Oxidative Cyclization ◽  
Coupling Reactions ◽  
Total Syntheses ◽  
Common Precursor ◽  
Key Steps

A parallel total synthesis of 16-F1t-, 16-E1-phytoprostanes and a first synthesis of 16-D1t-phytoprostanes based on a common precursor are described.

scholarly journals Bioinspired Oxidative Cyclization of the Geissoschizine Skeleton for the Enantioselective Total Synthesis of Mavacuran Alkaloids

2019 ◽  
Author(s):  
Maxime Jarret ◽  
Victor Turpin ◽  
Aurélien Tap ◽  
Jean-Francois Gallard ◽  
Cyrille Kouklovsky ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Oxidative Coupling ◽  
Indole Alkaloids ◽  
Oxidative Cyclization ◽  
Total Syntheses ◽  
Enantioselective Total Synthesis ◽  
Biosynthetic Precursor ◽  
Monoterpene Indole Alkaloids ◽  
Coupling Approach

We report the enantioselective total syntheses of mavacurans alkaloids, (+)-taberdivarine H, (+)-16-hydoxymethyl-pleiocarpamine, (+)-16-epi-pleiocarpamine, and their postulated biosynthetic precursor 16-formyl-pleiocarpamine. This family of monoterpene indole alkaloids is a target of choice since some of its members are subunits of intricate bisindole alkaloids such as bipleiophylline. Inspired by the biosynthetic hypothesis, we explored an oxidative coupling approach from the geissoschizine framework to form the N1-C16 bond. Quaternization of the aliphatic nitrogen was key to achieve the oxidative coupling induced by KHMDS/I<sub>2 </sub>since<sub> </sub>it hides the nucleophilicity of the aliphatic nitrogen and locks the required cis conformation.

Second-generation total synthesis of (−)-diversifolin

2010 ◽  
Vol 51 (14) ◽  
pp. 1876-1879 ◽  
Author(s):  
Kazuma Tsuboi ◽  
Tomoaki Nakamura ◽  
Takahiro Suzuki ◽  
Atsuo Nakazaki ◽  
Susumu Kobayashi
Keyword(s):  
Total Synthesis ◽  
Second Generation

Total Synthesis of (−)-Kainic Acid via Intramolecular Michael Addition: A Second-Generation Route

2008 ◽  
Vol 10 (9) ◽  
pp. 1711-1714 ◽  
Author(s):  
Hiroshi Sakaguchi ◽  
Hidetoshi Tokuyama ◽  
Tohru Fukuyama
Keyword(s):  
Total Synthesis ◽  
Kainic Acid ◽  
Michael Addition ◽  
Second Generation

scholarly journals First Total Synthesis and Investigation of the X-ray Crystal Structure of the Pyrano[3,2-a]carbazole Alkaloid Clausenalansine A

Synthesis ◽  
2020 ◽  
Vol 53 (02) ◽  
pp. 359-364
Author(s):  
Hans-Joachim Knölker ◽  
Valerie Lösle ◽  
Olga Kataeva
Keyword(s):  
Crystal Structure ◽  
Total Synthesis ◽  
Lewis Acid ◽  
Oxidative Cyclization ◽  
Formyl Group ◽  
Pyran Ring ◽  
X Ray ◽  
Synthetic Strategy

AbstractWe describe the first total synthesis of the recently discovered pyrano[3,2-a]carbazole alkaloid clausenalansine A. The synthetic strategy for the construction of this formylpyrano[3,2-a]carbazole is based on a sequence of Buchwald–Hartwig coupling, palladium(II)-catalyzed oxidative cyclization, Lewis acid promoted annulation of the pyran ring, and chemoselective oxidation of a methyl to a formyl group.

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