Total synthesis of bryostatin 3

Science ◽  
2020 ◽  
Vol 368 (6494) ◽  
pp. 1007-1011 ◽  
Author(s):  
Barry M. Trost ◽  
Youliang Wang ◽  
Andreas K. Buckl ◽  
Zhongxing Huang ◽  
Minh H. Nguyen ◽  
...  
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Marine Natural Products ◽  
Biological Activities ◽  
Step Count ◽  
Total Syntheses ◽  
Linear Sequence ◽  
Wide Range

Bryostatins are a family of 21 complex marine natural products with a wide range of potent biological activities. Among all the 21 bryostatins, bryostatin 3 is structurally the most complex. Whereas nine total syntheses of bryostatins have been achieved to date, bryostatin 3 has only been targeted once and required the highest number of steps to synthesize (43 steps in the longest linear sequence and 88 total steps). Here, we report a concise total synthesis of bryostatin 3 using 22 steps in the longest linear sequence and 31 total steps through a highly convergent synthetic plan by the use of highly atom-economical and chemoselective transformations in which alkynes played a major role in reducing step count.

scholarly journals Oxazolidinones as Chiral Auxiliaries in the Asymmetric 1,4-Conjugate Addition Reaction Applied to the Total Synthesis of Natural Products: A Supplemental Mini-Review

2018 ◽  
Vol 15 (1) ◽  
pp. 3-20 ◽  
Author(s):  
Vahideh Zadsirjan ◽  
Majid M. Heravi
Keyword(s):  
Total Synthesis ◽  
Biological Activities ◽  
Conjugate Addition ◽  
Chiral Auxiliary ◽  
Addition Reactions ◽  
Chiral Auxiliaries ◽  
Complex Molecules ◽  
Total Syntheses ◽  
Naturally Occurring ◽  
Wide Range

Background: The most frequently used chiral auxiliaries, oxazolidinones (Evans' oxazolidinones) have been employed in 1,4-congugate addition reactions to α,β-unsaturated carbonyl compounds. Supplementary to our previous reports in this mini-review, we attempted to underscore the applications of this strategy in a step (steps) in the total synthesis of some naturally occurring compounds exhibiting diverse biological activities. Objective: In this mini-review, we try to underscore the applications of oxazolidinones (Evans’ oxazolidinones) in 1,4-congugate addition reactions to α,β-unsaturated carbonyl in the total synthesis of some naturally occurring compounds exhibiting diverse biological activities. Conclusion: In spite of well-known superiority of asymmetric catalyzed reactions, the use of auxiliarycontrolled reactions are still considered as commanding, vital and sometimes as only tools in the generation of stereogenic centers during the construction of complex molecules and total synthesis of naturally occurring compounds. The commercial availability, or readily accessibility of a wide variety of chiral amino alcohols as starting materials to synthesize a wide range of oxazolidinones is the merits of them. In addition, the ease of removal and subjection to various and diverse stereoselective reactions make oxazolidinones as the ideal and superior chiral auxiliaries. In this regard, they were successfully used in asymmetric 1,4-conjugate addition reactions with high stereoselectivities. The high degree of asymmetric induction can be attributed to the rigid chelation of N-acyloxazolidinones with metal ions, as well as the covering of one face of the system by the bulkiness of 4-substituent. In summary, in this report, the importance of the applications of chiral oxazolidinones as suitable chiral auxiliaries in the stereoselective, 1,4-conjugate addition reactions in asymmetric synthesis and in particular, the total synthesis of naturally occurring compounds and some complex molecules were underscored. Noticeably, in these total syntheses, this chiral auxiliary is controlling the stereochemistry of a newly created stereogenic center as well as preserving the configuration of other chiral centers, which already have been presented in the precursor. General methods have been established for the attachment of the chiral auxiliary as a moiety to the substrate molecule in high to excellent yields. At the end of these reactions, this auxiliary can be easily removed leaving various desired reactive motifs for the next step in multi-step synthesis.

Total synthesis of the potent antifungal agents bengazole C and E

2009 ◽  
Vol 74 (6) ◽  
pp. 887-900 ◽  
Author(s):  
Álvaro Enríquez-García ◽  
Steven V. Ley
Keyword(s):  
Natural Products ◽  
Antifungal Activity ◽  
Total Synthesis ◽  
Marine Natural Products ◽  
Antifungal Agents ◽  
Nitrile Oxide ◽  
Total Syntheses ◽  
Unique Structure

The bengazoles are marine natural products with unique structure, containing two oxazole rings flanking a single carbon. They show very potent antifungal activity. The total syntheses of bengazole C and E are described following a convergent route which involves diastereoselective cycloaddition of an appropriately substituted nitrile oxide with a butane-1,2-diacetal-protected alkenediol as the key step.

Enantioselective Total Syntheses of Marine Natural Products (+)-Cylindricines C, D, E and Their Diastereomers

2021 ◽  
Author(s):  
Ying-Hong Huang ◽  
Zhan-Jiang Liu ◽  
Pei-Qiang Huang
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Marine Natural Products ◽  
Total Syntheses

A seven-step total synthesis of (+)-cylindricine D and epi-cylindricine D is described. The efficiency relies on the highly diastereoselective reductive bis-functionalization of N,O-protected (S)-pyroglutaminol by our recently improved protocol to...

scholarly journals Marine Natural Products from Tunicates and Their Associated Microbes

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 308
Author(s):  
Chatragadda Ramesh ◽  
Bhushan Rao Tulasi ◽  
Mohanraju Raju ◽  
Narsinh Thakur ◽  
Laurent Dufossé
Keyword(s):  
Natural Products ◽  
Marine Natural Products ◽  
Biological Activities ◽  
Biological Properties ◽  
Anticancer Activities ◽  
Microbial Association ◽  
Wide Range ◽  
Microbial Groups ◽  
Global Oceans

Marine tunicates are identified as a potential source of marine natural products (MNPs), demonstrating a wide range of biological properties, like antimicrobial and anticancer activities. The symbiotic relationship between tunicates and specific microbial groups has revealed the acquisition of microbial compounds by tunicates for defensive purpose. For instance, yellow pigmented compounds, “tambjamines”, produced by the tunicate, Sigillina signifera (Sluiter, 1909), primarily originated from their bacterial symbionts, which are involved in their chemical defense function, indicating the ecological role of symbiotic microbial association with tunicates. This review has garnered comprehensive literature on MNPs produced by tunicates and their symbiotic microbionts. Various sections covered in this review include tunicates’ ecological functions, biological activities, such as antimicrobial, antitumor, and anticancer activities, metabolic origins, utilization of invasive tunicates, and research gaps. Apart from the literature content, 20 different chemical databases were explored to identify tunicates-derived MNPs. In addition, the management and exploitation of tunicate resources in the global oceans are detailed for their ecological and biotechnological implications.

Marine Natural Products with High Anticancer Activities

2020 ◽  
Vol 27 (8) ◽  
pp. 1243-1307 ◽  
Author(s):  
Dario Matulja ◽  
Karlo Wittine ◽  
Nela Malatesti ◽  
Sylvain Laclef ◽  
Maris Turks ◽  
...  
Keyword(s):  
Natural Products ◽  
Marine Natural Products ◽  
Cancer Biology ◽  
Molecular Mechanisms ◽  
Recent Literature ◽  
Biological Activities ◽  
Anticancer Activities ◽  
Total Syntheses ◽  
Biosynthetic Studies ◽  
Shed Light

This review covers recent literature from 2012-2019 concerning 170 marine natural products and their semisynthetic analogues with strong anticancer biological activities. Reports that shed light on cellular and molecular mechanisms and biological functions of these compounds, thus advancing the understanding in cancer biology are also included. Biosynthetic studies and total syntheses, which have provided access to derivatives and have contributed to the proper structure or stereochemistry elucidation or revision are mentioned. The natural compounds isolated from marine organisms are divided into nine groups, namely: alkaloids, sterols and steroids, glycosides, terpenes and terpenoids, macrolides, polypeptides, quinones, phenols and polyphenols, and miscellaneous products. An emphasis is placed on several drugs originating from marine natural products that have already been marketed or are currently in clinical trials.

scholarly journals Bicyclo [6.3.0] Undecane Sesquiterpenoids: Structures, Biological Activities, and Syntheses

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3912 ◽  
Author(s):  
Guo-Fei Qin ◽  
Hong-Bao Liang ◽  
Wen-Xiu Liu ◽  
Feng Zhu ◽  
Ping-Lin Li ◽  
...  
Keyword(s):  
Natural Products ◽  
Biological Activities ◽  
Membered Ring ◽  
Isopropyl Group ◽  
Total Syntheses ◽  
The Core ◽  
Naturally Occurring ◽  
Important Target ◽  
Wide Range ◽  
Antiviral Activities

Sesquiterpenoids constitute a marvelously varied group of natural products that feature a vast array of molecular architectures. Among them, the unusual bicyclo [6.3.0] undecane sesquiterpenoids are one of the most representative. To date, only approximately 42 naturally occurring compounds with this unique scaffold, which can be classified into seven different groups, have been reported. As the first-found member of each type, dactylol, asteriscanolide, dumortenol, toxicodenane C, and capillosanane S are characteristic of the four methyl groups on the five-eight-membered ring system. Only 11-hydroxyjasionone and sinuketal decorate the core with an isopropyl group. These natural products exhibit a wide range of bioactivities, including antifouling, anti-inflammatory, immune suppression, cytotoxic, antimutagenic, antiplasmodial, and antiviral activities. It was noted that some total syntheses of precapnellane-sesquiterpenoids (dactylol, poitediol, precapnelladiene), asteriscanolide, and 11-hydroxyjasionone have been achieved, because their cyclooctanoid core represents an important target for the development of synthetic strategies to prepare eight-membered ring-containing compounds. This review focuses on these natural sesquiterpenoids and their biological activities and synthesis, and aims to provide a foundation for further research of these interesting compounds.

Pyrone-derived Marine Natural Products: A Review on Isolation, Bio-activities and Synthesis

2020 ◽  
Vol 24 (4) ◽  
pp. 354-401 ◽  
Author(s):  
Keisham S. Singh
Keyword(s):  
Natural Products ◽  
Marine Natural Products ◽  
Marine Fungi ◽  
Kojic Acid ◽  
Biological Activities ◽  
Biological Significance ◽  
Pyrone Ring ◽  
Enol Ethers ◽  
Bioactive Natural Products ◽  
Marine Metabolites

Marine natural products (MNPs) containing pyrone rings have been isolated from numerous marine organisms, and also produced by marine fungi and bacteria, particularly, actinomycetes. They constitute a versatile structure unit of bioactive natural products that exhibit various biological activities such as antibiotic, antifungal, cytotoxic, neurotoxic, phytotoxic and anti-tyrosinase. The two structure isomers of pyrone ring are γ- pyrone and α-pyrone. In terms of chemical motif, γ-pyrone is the vinologous form of α- pyrone which possesses a lactone ring. Actinomycete bacteria are responsible for the production of several α-pyrone compounds such as elijopyrones A-D, salinipyrones and violapyrones etc. to name a few. A class of pyrone metabolites, polypropionates which have fascinating carbon skeleton, is primarily produced by marine molluscs. Interestingly, some of the pyrone polytketides which are found in cone snails are actually synthesized by actinomycete bacteria. Several pyrone derivatives have been obtained from marine fungi such as Aspergillums flavus, Altenaria sp., etc. The γ-pyrone derivative namely, kojic acid obtained from Aspergillus fungus has high commercial demand and finds various applications. Kojic acid and its derivative displayed inhibition of tyrosinase activity and, it is also extensively used as a ligand in coordination chemistry. Owing to their commercial and biological significance, the synthesis of pyrone containing compounds has been given attention over the past years. Few reviews on the total synthesis of pyrone containing natural products namely, polypropionate metabolites have been reported. However, these reviews skipped other marine pyrone metabolites and also omitted discussion on isolation and detailed biological activities. This review presents a brief account of the isolation of marine metabolites containing a pyrone ring and their reported bio-activities. Further, the review covers the synthesis of marine pyrone metabolites such as cyercene-A, placidenes, onchitriol-I, onchitriol-II, crispatene, photodeoxytrichidione, (-) membrenone-C, lihualide-B, macrocyclic enol ethers and auripyrones-A & B.

scholarly journals Xylochemical Synthesis and Biological Evaluation of Shancigusin C and Bletistrin G

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3224
Author(s):  
Leander Geske ◽  
Ulrich Kauhl ◽  
Mohamed E. M. Saeed ◽  
Anja Schüffler ◽  
Eckhard Thines ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Biological Activities ◽  
Biological Evaluation ◽  
Aromatic Substitution ◽  
Substitution Reactions ◽  
Total Syntheses ◽  
Wittig Olefination ◽  
Starting Point ◽  
Perkin Reaction ◽  
Synthesis And Biological Evaluation

The biological activities of shancigusin C (1) and bletistrin G (2), natural products isolated from orchids, are reported along with their first total syntheses. The total synthesis of shancigusin C (1) was conducted by employing the Perkin reaction to forge the central stilbene core, whereas the synthesis of bletistrin G (2) was achieved by the Wittig olefination followed by several regioselective aromatic substitution reactions. Both syntheses were completed by applying only renewable starting materials according to the principles of xylochemistry. The cytotoxic properties of shancigusin C (1) and bletistrin G (2) against tumor cells suggest suitability as a starting point for further structural variation.

scholarly journals Modern Synthetic Methods for the Stereoselective Construction of 1,3-Dienes

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 249
Author(s):  
Raquel G. Soengas ◽  
Humberto Rodríguez-Solla
Keyword(s):  
Organic Chemistry ◽  
Natural Products ◽  
Functional Group ◽  
Biological Activities ◽  
Synthetic Methods ◽  
Bond Forming ◽  
Drug Candidates ◽  
The Past ◽  
Wide Range

The 1,3-butadiene motif is widely found in many natural products and drug candidates with relevant biological activities. Moreover, dienes are important targets for synthetic chemists, due to their ability to give access to a wide range of functional group transformations, including a broad range of C-C bond-forming processes. Therefore, the stereoselective preparation of dienes have attracted much attention over the past decades, and the search for new synthetic protocols continues unabated. The aim of this review is to give an overview of the diverse methodologies that have emerged in the last decade, with a focus on the synthetic processes that meet the requirements of efficiency and sustainability of modern organic chemistry.

Total synthesis of marine natural products separacenes A and B

2017 ◽  
Vol 15 (22) ◽  
pp. 4842-4850 ◽  
Author(s):  
Subhendu Das ◽  
Rajib Kumar Goswami
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Marine Natural Products
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