scholarly journals Towards the total synthesis of keramaphidin B

2016 ◽  
Vol 12 ◽  
pp. 1096-1100 ◽  
Author(s):  
Pavol Jakubec ◽  
Alistair J M Farley ◽  
Darren J Dixon

The enantio- and diastereoselective Michael addition of a δ-valerolactone-derived pronucleophile to a substituted furanyl nitroolefin catalysed by a bifunctional cinchonine-derived thiourea has been used as the key stereocontrolling step in a new synthetic strategy to the heavily functionalised piperidine core of keramaphidin B.

2018 ◽  
Author(s):  
Timothy Newhouse ◽  
Daria E. Kim ◽  
Joshua E. Zweig

The diverse molecular architectures of terpene natural products are assembled by exquisite enzyme-catalyzed reactions. Successful recapitulation of these transformations using chemical synthesis is hard to predict from first principles and therefore challenging to execute. A means of evaluating the feasibility of such chemical reactions would greatly enable the development of concise syntheses of complex small molecules. Herein, we report the computational analysis of the energetic favorability of a key bio-inspired transformation, which we use to inform our synthetic strategy. This approach was applied to synthesize two constituents of the historically challenging indole diterpenoid class, resulting in a concise route to (–)-paspaline A in 9 steps from commercially available materials and the first pathway to and structural confirmation of emindole PB in 13 steps. This work highlights how traditional retrosynthetic design can be augmented with quantum chemical calculations to reveal energetically feasible synthetic disconnections, minimizing time-consuming and expensive empirical evaluation.


2021 ◽  
Author(s):  
◽  
Benjamin Mark Mandinka Deeble

<p>Azasugars are structural analogues of carbohydrates whereby the oxygen in the heterocyclic ring is substituted for a nitrogen. These carbohydrates are an important class of compounds with medicinal bioactivities and have shown potential for the treatment of diabetes, viral-infection, cancers, and lysosomal storage diseases. 1-deoxymannojirimycin (DMJ), is a mannosidase inhibiting azasugar which has shown anti-cancer and anti-viral activity. There has been significant effort put towards developing methodology to produce this compound and libraries of its derivatives. This thesis presents the synthesis of DMJ and a selection of its derivatives via an efficient 4 step methodology from a carbohydrate starting material, exploiting chemo and regioselective reactions to allow for a total synthesis with minimal use of protecting groups. The synthesis of DMJ, using the methodology developed herein, surpasses published syntheses in efficiency. This synthetic strategy was then used for the preparation of N-functionalised DMJ derivatives without the requirement of additional synthetic steps. To illustrate the versatility of this methodology, a selection of derivatives incorporating different functionalities have been synthesised.</p>


1990 ◽  
Vol 68 (11) ◽  
pp. 1917-1922 ◽  
Author(s):  
Réjean Ruel ◽  
Pierre Deslongchamps

The total synthesis of the title compound 22 and methyl 14α-hydroxy-5β,13α,8-androstene-1,7,17-trioxo-10β-oate 21 isomer is reported. We also describe the 1,6-Michael addition of 2-methyl-1,3-cyclopentanedione on dienone 14 and the protic ammonium salt catalyzed intramolecular Michael addition of cyclic β-ketoester on the conjugated acetylenic ketone 13. Keywords: cardenolides, steroid synthesis, aldol, Michael addition.


2005 ◽  
Vol 117 (34) ◽  
pp. 5569-5574 ◽  
Author(s):  
Matthew Ball ◽  
Matthew J. Gaunt ◽  
David F. Hook ◽  
Alan S. Jessiman ◽  
Shigeru Kawahara ◽  
...  

2021 ◽  
Author(s):  
Yi An ◽  
Mengjuan Wu ◽  
Weijian Li ◽  
Yaling Li ◽  
Zhenzhen Wang ◽  
...  

Reported herein a concise and enantioselective total synthesis of Schizozygine alkaloids (–)-strempeliopine. This synthetic strategy features a palladium-catalyzed decarboxylative asymmetric allylic alkylation of N-benzoyl lactam to set up the absolute...


Synthesis ◽  
2021 ◽  
Author(s):  
alexandre guy ◽  
Jérémy Merad ◽  
Thomas Degrange ◽  
Guillaume Reversat ◽  
Valérie Bultel-Poncé ◽  
...  

Oxylipins are formed in-vivo from polyunsaturated fatty acids (PUFAs). A large structural variety of compounds is grouped under the term oxylipins, which differ from their formation mechanism (involving enzymes or not), as well as their chemical structures (cyclopentanes, tetrahydrofurans, hydroxylated-PUFA etc.). All structures of oxylipins are of great biological interests. Directly correlated to oxidative stress phenomenon, non-enzymatic oxylipins are used as systemic and/or specific biomarkers in various pathologies and more especially, they were found to have their own biological properties. Produced in-vivo as a non-separable mixture of isomers, total synthesis is a keystone to answer biological questions. In this work, we described the total synthesis of three non-enzymatic oxylipins derived from docosahexaenoic acid (DHA) and docosapentanoic acid (DPAn-3) using a unique and convergent synthetic strategy.


2008 ◽  
Vol 10 (9) ◽  
pp. 1711-1714 ◽  
Author(s):  
Hiroshi Sakaguchi ◽  
Hidetoshi Tokuyama ◽  
Tohru Fukuyama

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