Enabling strategies for step efficient syntheses

2018 ◽  
Vol 47 (21) ◽  
pp. 7985-7995 ◽  
Author(s):  
Johannes Schwan ◽  
Mathias Christmann

The field of natural product total synthesis has reached the point where synthetic efficiency has become more important than merely defining a viable (yet less ideal) route to the target molecule. Several synthesis of different types of natural products are compared using color-coded flow charts.

2019 ◽  
Author(s):  
Lars Gnägi ◽  
Severin Vital Martz ◽  
Daniel Meyer ◽  
Robin Marc Schärer ◽  
Philippe Renaud

<div><div><div><div><p>A very concise total synthesis of (+)-brefeldin C starting from 2-furanylcyclopentene is described. This approach is based on an unprecedented enantioselective radical hydroalkynylation process to introduce the two cyclopentane stereocenters in a single step. The use of a furan substituent allows to achieve a high trans diastereoselectivity during the radical process and it contains the four carbon atoms C1–C4 of the natural product in an oxidation state closely related to the one of the target molecule. The eight-step synthesis require six product purifications and it provides (+)-brefeldin C in 18% overall yield.</p></div></div></div></div>


2014 ◽  
Vol 10 ◽  
pp. 1228-1232 ◽  
Author(s):  
Jens Schmidt ◽  
Zeinab Khalil ◽  
Robert J Capon ◽  
Christian B W Stark

The heronapyrroles A–C have first been isolated from a marine-derived Streptomyces sp. (CMB-0423) in 2010. Structurally, these natural products feature an unusual nitropyrrole system to which a partially oxidized farnesyl chain is attached. The varying degree of oxidation of the sesquiterpenyl subunit in heronapyrroles A–C provoked the hypothesis that there might exist other hitherto unidentified metabolites. On biosynthetic grounds a mono-tetrahydrofuran-diol named heronapyrrole D appeared a possible candidate. We here describe a short asymmetric synthesis of heronapyrrole D, its detection in cultivations of CMB-0423 and finally the evaluation of its antibacterial activity. We thus demonstrate that biosynthetic considerations and the joint effort of synthetic and natural product chemists can result in the identification of new members of a rare class of natural products.


2020 ◽  
Author(s):  
Justin Shapiro ◽  
Savannah Post ◽  
William Wuest

In a 2016 screen of natural product extracts a new family of natural products, the cahuitamycins, was discovered and found to inhibit the formation of biofilms in the human pathogen <i>Acinetobacter baumannii</i>. The molecules contain an unusual piperazate residue that raises structure/function and biosynthesis questions and resemble iron-trafficking virulence factors from <i>A. baumannii</i>, suggesting a connection between metal homeostasis and biofilm-mediated pathogenicity. Here we disclose the first total synthesis of the reported structure of cahuitamycin A in a twelve-step longest linear sequence and 18% overall yield. Comparison of spectral data of the authentic natural product and synthetic target compound demonstrate that the reported structure is distinct from the isolated metabolite. Herein, we propose an alternative structure to reconcile our findings with the isolation report, setting the stage for future synthetic and biochemical investigations of an important class of natural products.


2000 ◽  
Vol 72 (9) ◽  
pp. 1783-1786 ◽  
Author(s):  
Keisuke Suzuki

Strategies and tactics associated with the total synthesis of hybrid natural products are discussed. The target is ravidomycin (2), one of the gilvocarcin-class antitumor antibiotics with an aryl C-glycoside structure. The first total synthesis of 2, which was achieved along similar lines of that of gilvocarcin V (1), served for the determination of the relative as well as the absolute stereochemistry of 2. Also revealed was a limitation of the synthetic scheme so long as the amino sugar congener was concerned. A preliminary result is discussed on the [2+2+2] approach that relies on the ready availability of various benzocyclobutene derivatives via regioselective [2+2] cycloaddition of α-alkoxybenzynes and ketene silyl acetals.


2020 ◽  
Vol 37 (8) ◽  
pp. 1065-1079 ◽  
Author(s):  
Christian R. Zwick ◽  
Hans Renata

This review highlights recent chemoenzymatic syntheses of natural products that feature strategic applications of oxidative transformations with Fe/αKG enzymes.


2019 ◽  
Vol 17 (31) ◽  
pp. 7270-7292 ◽  
Author(s):  
Sagar S. Thorat ◽  
Ravindar Kontham

Oxaspirolactones are ubiquitous structural motifs found in natural products and synthetic molecules with a diverse biochemical and physicochemical profile, and represent a valuable target in natural product chemistry and medicinal chemistry.


2018 ◽  
Vol 5 (1) ◽  
pp. 132-150 ◽  
Author(s):  
Pengquan Chen ◽  
Yuecheng Wu ◽  
Shifa Zhu ◽  
Huanfeng Jiang ◽  
Zhiqiang Ma

This review highlights the recent applications of Ir-catalyzed reactions in the total synthesis of natural products.


2020 ◽  
Author(s):  
Peter Ertl ◽  
Tim Schuhmann

AbstractNatural products (NPs) have evolved over a very long natural selection process to form optimal interactions with biologically relevant macromolecules. NPs are therefore an extremely useful source of inspiration for the design of new drugs. In the present study we report the results of a cheminformatics analysis of a large database of NP structures focusing on their scaffolds. First, general differences between NP scaffolds and scaffolds from synthetic molecules are discussed, followed by a comparison of the properties of scaffolds produced by different types of organisms. Scaffolds produced by plants are the most complex and those produced by bacteria differ in many structural features from scaffolds produced by other organisms. The results presented here may be used as a guidance in selection of scaffolds for the design of novel NP-like bioactive structures or NP-inspired libraries.


2021 ◽  
Author(s):  
◽  
R.M. Kalpani K. Somarathne

<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>


2018 ◽  
Vol 16 (35) ◽  
pp. 6372-6390 ◽  
Author(s):  
Saumitra Sengupta ◽  
Goverdhan Mehta

Natural product modulators of the cAMP pathway have been evaluated and their total synthesis campaign is described in detail.


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