scholarly journals Total synthesis of biseokeaniamides A–C and late-stage electrochemically-enabled peptide analogue synthesis

2020 ◽  
Vol 11 (39) ◽  
pp. 10752-10758 ◽  
Author(s):  
Yutong Lin ◽  
Lara R. Malins

A late-stage electrochemical decarboxylation enables rapid access to structural analogues of biseokeaniamides A–C, cytotoxic lipopeptide natural products.

2011 ◽  
Vol 84 (6) ◽  
pp. 1379-1390 ◽  
Author(s):  
Michael C. McLeod ◽  
Margaret A. Brimble ◽  
Dominea C. K. Rathwell ◽  
Zoe E. Wilson ◽  
Tsz-Ying Yuen

Studies toward the synthesis of three biologically active [5,6]-benzannulated spiroketal natural products are described. The first total synthesis of paecilospirone is reported, employing a late-stage, pH-neutral spiroketalization. A formal synthesis of γ-rubromycin is described, where the spiroketal moiety is formed by delicate manipulation of the electronic properties of the spirocyclization precursor. Finally, model work toward the total synthesis of berkelic acid is summarized, introducing a novel Horner–Wadsworth–Emmons/oxa-Michael (HWE/oxa-M) cascade to access the spiroketal precursor.


Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4848
Author(s):  
Yngve Guttormsen ◽  
Magnus E. Fairhurst ◽  
Sunil K. Pandey ◽  
Johan Isaksson ◽  
Bengt Erik Haug ◽  
...  

Phorbazoles are polychlorinated heterocyclic secondary metabolites isolated from a marine sponge and several of these natural products have shown inhibitory activity against cancer cells. In this work, a synthesis of the trichlorinated phorbazole B using late stage electrophilic chlorination was developed. The synthesis relied on the use of an oxazole precursor, which was protected with an iodine in the reactive 4-position, followed by complete chlorination of all pyrrole positions. Attempts to prepare phorbazole A and C, which contain a 3,4-dichlorinated pyrrole, were unsuccessful as the desired chlorination pattern on the pyrrole could not be obtained. The identities of the dichlorinated intermediates and products were determined using NMR techniques including NOESY/ROESY, 1,1-ADEQUATE and high-resolution CLIP-HSQMBC.


2020 ◽  
Vol 18 (40) ◽  
pp. 8109-8118
Author(s):  
Matthew J. Anketell ◽  
Theodore M. Sharrock ◽  
Ian Paterson

A convergent synthesis of the actinoallolides with late-stage diversification provides access to a photoaffinity probe to identify the target of these potent anti-trypanosomal natural products.


Synthesis ◽  
2019 ◽  
Vol 51 (09) ◽  
pp. 2001-2006 ◽  
Author(s):  
Egor Chirkin ◽  
Chouaha Bouzidi ◽  
François-Hugues Porée

Herein, we report a concise enantioselective synthesis of (–)-allosecurinine, a tetracyclic Securinega alkaloid featuring an α,β-unsaturated γ-lactone moiety. Starting from inexpensive and readily available trans-l-hydroxyproline, our strategy entails a rare late-stage [2+2+1]-hetero-Pauson–Khand cycloaddition between a ketone and an alkyne as the key complexity-generating step to rapidly install the CD-ring system. The reported W(CO)6-promoted intramolecular cyclization provides the first example of a tungsten-mediated hetero-Pauson–Khand reaction. This approach to the strained bicyclic CD motif present in ­allosecurinine provides some insights into the boundaries of this potentially powerful methodology that might be further extended to other butenolide-containing natural products.


2009 ◽  
Vol 131 (13) ◽  
pp. 4904-4916 ◽  
Author(s):  
Hayato Ishikawa ◽  
David A. Colby ◽  
Shigeki Seto ◽  
Porino Va ◽  
Annie Tam ◽  
...  

Marine Drugs ◽  
2021 ◽  
Vol 19 (5) ◽  
pp. 273
Author(s):  
Antonio Rosales Martínez ◽  
Ignacio Rodríguez-García ◽  
Josefa L. López-Martínez

The divergent total synthesis strategy can be successfully applied to the preparation of families of natural products using a common late-stage pluripotent intermediate. This approach is a powerful tool in organic synthesis as it offers opportunities for the efficient preparation of structurally related compounds. This article reviews the synthesis of the marine natural product aureol, as well as its use as a common intermediate in the divergent synthesis of other marine natural and non-natural tetracyclic meroterpenoids.


2019 ◽  
Author(s):  
Florian Bartels ◽  
Manuela Weber ◽  
Mathias Christmann

<div>An efficient strategy for the synthesis of the potent phospholipase A2 inhibitors spongidine A and D is presented. The tetracyclic core of the natural products was assembled via an intramolecular hydrogen atom transfer‐initiated Minisci reaction. A divergent late‐stage functionalization of the tetracyclic ring system was also used to achieve a concise synthesis of petrosaspongiolide L methyl ester.</div>


2019 ◽  
Author(s):  
Timothy Newhouse ◽  
Aneta Turlik ◽  
Yifeng Chen ◽  
Anthony Scruse

<div> <p>The total synthesis of principinol D, a rearranged kaurane diterpenoid, is reported. This grayanane natural product is constructed via a convergent fragment coupling approach, wherein the central 7-membered ring is synthesized at a late stage. The bicyclo[3.2.1]octane fragment is accessed by a Ni-catalyzed α-vinylation reaction. Strategic reductions include a diastereoselective SmI<sub>2</sub>-mediated ketone reduction with PhSH and a new protocol for selective ester reduction in the presence of ketones. The convergent strategy reported herein may be an entry point to the larger class of kaurane diterpenoids.</p> </div>


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