1
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Tian DS, Zhang X, Cox RJ. Comparing total chemical synthesis and total biosynthesis routes to fungal specialized metabolites. Nat Prod Rep 2024. [PMID: 39145774 DOI: 10.1039/d4np00015c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2024]
Abstract
Covering the period 1965-2024Total synthesis has been defined as the art and science of making the molecules of living Nature in the laboratory, and by extension, their analogues. At the extremes, specialised metabolites can be created by total chemical synthesis or by total biosynthesis. In this review we explore the advantages and disadvantages of these two approaches using quantitative methodology that combines measures of molecular complexity, molecular weight and fraction of sp3 centres for bioactive fungal metabolites. Total biosynthesis usually involves fewer chemical steps and those steps move more directly to the target than comparable total chemical synthesis. However, total biosynthesis currently lacks the flexibility of chemical synthesis and the ability to easily diversify synthetic routes.
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Affiliation(s)
- Dong-Song Tian
- College of Pharmaceutical Sciences, Southwest University, 400715 Chongqing, China.
| | - Xiao Zhang
- College of Pharmaceutical Sciences, Southwest University, 400715 Chongqing, China.
| | - Russell J Cox
- Institute for Organic Chemistry, Leibniz University of Hannover, Schneiderberg 38, 30167 Hannover, Germany.
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2
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Peng C, Guo Q, Xu GX, Huo L, Wu W, Chen TY, Hong X, Hu P. Divergent Synthesis of Scabrolide A and Havellockate via an exo- exo- endo Radical Cascade. J Am Chem Soc 2024; 146:14422-14426. [PMID: 38709624 DOI: 10.1021/jacs.4c03995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Here we report a concise and divergent synthesis of scabrolide A and havellockate, representative members of polycyclic marine natural product furano(nor)cembranoids. The synthesis features a highly efficient exo-exo-endo radical cascade. Through the generation of two rings, three C-C bonds, and three contiguous stereocenters in one step, this remarkable transformation not only assembles the bowl-shaped, common 6-5-5 fused ring system from simple building blocks but also precisely installs the functionalities at desired positions and sets the stage for further divergent preparation of both target molecules. Further studies reveal that the robust and unusual 6-endo radical addition in the cascade is likely facilitated by the rigidity of the substrate.
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Affiliation(s)
- Chen Peng
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science, and Research Center for Industries of the Future, Westlake University, Hangzhou, 310030, China
| | - Quanping Guo
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science, and Research Center for Industries of the Future, Westlake University, Hangzhou, 310030, China
| | - Guo-Xiong Xu
- Center of Chemistry for Frontier Technologies, Department of Chemistry, State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China
| | - Luqiong Huo
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science, and Research Center for Industries of the Future, Westlake University, Hangzhou, 310030, China
| | - Weilin Wu
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science, and Research Center for Industries of the Future, Westlake University, Hangzhou, 310030, China
| | - Tian-Yi Chen
- Center of Chemistry for Frontier Technologies, Department of Chemistry, State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China
| | - Xin Hong
- Center of Chemistry for Frontier Technologies, Department of Chemistry, State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China
| | - Pengfei Hu
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science, and Research Center for Industries of the Future, Westlake University, Hangzhou, 310030, China
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3
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Alleman C, Gadais C, Legentil L, Porée FH. Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series. Beilstein J Org Chem 2023; 19:245-281. [PMID: 36895430 PMCID: PMC9989678 DOI: 10.3762/bjoc.19.23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 02/13/2023] [Indexed: 03/06/2023] Open
Abstract
Terpene compounds probably represent the most diversified class of secondary metabolites. Some classes of terpenes, mainly diterpenes (C20) and sesterterpenes (C25) and to a lesser extent sesquiterpenes (C15), share a common bicyclo[3.6.0]undecane core which is characterized by the presence of a cyclooctane ring fused to a cyclopentane ring, i.e., a [5-8] bicyclic ring system. This review focuses on the different strategies elaborated to construct this [5-8] bicyclic ring system and their application in the total synthesis of terpenes over the last two decades. The overall approaches involve the construction of the 8-membered ring from an appropriate cyclopentane precursor. The proposed strategies include metathesis, Nozaki-Hiyama-Kishi (NHK) cyclization, Pd-mediated cyclization, radical cyclization, Pauson-Khand reaction, Lewis acid-promoted cyclization, rearrangement, cycloaddition and biocatalysis.
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Affiliation(s)
- Cécile Alleman
- Université Rennes, Faculté de Pharmacie, CNRS ISCR UMR 6226, F-35000 Rennes, France
| | - Charlène Gadais
- Université Rennes, Faculté de Pharmacie, CNRS ISCR UMR 6226, F-35000 Rennes, France
| | - Laurent Legentil
- Université Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS, ISCR - UMR 6226, F-35000 Rennes, France
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4
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Goethe O, DiBello M, Herzon SB. Total synthesis of structurally diverse pleuromutilin antibiotics. Nat Chem 2022; 14:1270-1277. [PMID: 36163267 PMCID: PMC9633427 DOI: 10.1038/s41557-022-01027-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 07/21/2022] [Indexed: 11/08/2022]
Abstract
The emergence of drug-resistant bacterial pathogens has placed renewed emphasis on the total chemical synthesis of novel antibacterials. Tetracyclines, macrolides, streptogramins and lincosamides are now accessible through flexible and general synthetic routes. Pleuromutilins (antibiotics based on the fungal metabolite pleuromutilin) have remained resistant to this approach, in large part due to the difficulties encountered in the de novo construction of the decahydro-3a,9-propanocyclopenta[8]annulene skeleton. Here we present a platform for the total synthesis of pleuromutilins that provides access to diverse derivatives bearing alterations at previously inaccessible skeletal and peripheral positions. The synthesis is enabled by the serendipitous discovery of a vinylogous Wolff rearrangement, which serves to establish the C9 quaternary centre in the targets, and the development of a highly diastereoselective butynylation of an α-quaternary aldehyde, which forms the C14 secondary alcohol. The versatility of the route is demonstrated through the synthesis of seventeen structurally distinct derivatives, with many possessing potent antibacterial activity.
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Affiliation(s)
- Olivia Goethe
- Department of Chemistry, Yale University, New Haven, CT, USA
| | - Mikaela DiBello
- Department of Chemistry, Yale University, New Haven, CT, USA
| | - Seth B Herzon
- Department of Chemistry, Yale University, New Haven, CT, USA.
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, USA.
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5
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Chen H, Li Z, Shao P, Yuan H, Chen SC, Luo T. Total Synthesis of (+)-Mutilin: A Transannular [2+2] Cycloaddition/Fragmentation Approach. J Am Chem Soc 2022; 144:15462-15467. [DOI: 10.1021/jacs.2c06934] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Han Chen
- Key Laboratory of Bioorganic Chemistry and Molecular Engineering, Ministry of Education and Beijing National Laboratory for Molecular Science, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Zesheng Li
- Key Laboratory of Bioorganic Chemistry and Molecular Engineering, Ministry of Education and Beijing National Laboratory for Molecular Science, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Peng Shao
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Haosen Yuan
- Key Laboratory of Bioorganic Chemistry and Molecular Engineering, Ministry of Education and Beijing National Laboratory for Molecular Science, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Si-Cong Chen
- Key Laboratory of Bioorganic Chemistry and Molecular Engineering, Ministry of Education and Beijing National Laboratory for Molecular Science, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Tuoping Luo
- Key Laboratory of Bioorganic Chemistry and Molecular Engineering, Ministry of Education and Beijing National Laboratory for Molecular Science, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen, Guangdong 518055, China
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6
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Morrill C, Péter Á, Amalina I, Pye E, Crisenza GEM, Kaltsoyannis N, Procter DJ. Diastereoselective Radical 1,4-Ester Migration: Radical Cyclizations of Acyclic Esters with SmI 2. J Am Chem Soc 2022; 144:13946-13952. [PMID: 35858251 PMCID: PMC9377304 DOI: 10.1021/jacs.2c05972] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Reductive cyclizations of carbonyl compounds, mediated
by samarium(II)
diiodide (SmI2, Kagan’s reagent), represent an invaluable
platform to generate molecular complexity in a stereocontrolled manner.
In addition to classical ketone and aldehyde substrates, recent advances
in radical chemistry allow the cyclization of lactone and lactam-type
substrates using SmI2. In contrast, acyclic esters are
considered to be unreactive to SmI2 and their participation
in reductive cyclizations is unprecedented. Here, we report a diastereoselective
radical 1,4-ester migration process, mediated by SmI2,
that delivers stereodefined alkene hydrocarboxylation products via
radical cyclization of acyclic ester groups in α-carbomethoxy
δ-lactones. Isotopic labeling experiments and computational
studies have been used to probe the mechanism of the migration. We
propose that a switch in conformation redirects single electron transfer
from SmI2 to the acyclic ester group, rather than the “more
reactive” lactone carbonyl. Our study paves the way for the
use of elusive ketyl radicals, derived from acyclic esters, in SmI2-mediated reductive cyclizations.
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Affiliation(s)
- Charlotte Morrill
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Áron Péter
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Ilma Amalina
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Emma Pye
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Giacomo E M Crisenza
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Nikolas Kaltsoyannis
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - David J Procter
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
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7
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Abstract
Synthesis of a potent inhibitor of bacterial protein synthesis, pleuromutilin, is described. Assembly of the critical cyclooctane fragment relies on an oxidative ring-expansion, and complete stereochemical relay in the synthetic sequence is enabled by the judicious choice of tactics. The requisite connectivity pattern of the perhydroindanone motif is rapidly established in a sequence of cycloaddition and radical cyclization events. Application of this strategy allows for preparation of the target natural product in 16 steps from commercially available material.
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Affiliation(s)
- Nicholas J Foy
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Sergey V Pronin
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
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8
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Galliher MS, Roldan BJ, Stephenson CRJ. Evolution towards green radical generation in total synthesis. Chem Soc Rev 2021; 50:10044-10057. [PMID: 34350919 PMCID: PMC9074136 DOI: 10.1039/d1cs00411e] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The use of radicals as intermediates in total synthesis has evolved since their initial use in the latter half of the twentieth century. Radical generation from metal hydride methodologies has shifted to "greener" techniques including catalytic metal-mediated systems, electrochemical and photoredox-mediated processes. This review will focus on these classical and contemporary methods for radical generation and their applications in recent total syntheses.
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Affiliation(s)
- Matthew S Galliher
- Department of Chemistry, University of Michigan, 930 N. University Ave, Ann Arbor, MI 48109, USA.
| | - Bec J Roldan
- Department of Chemistry, University of Michigan, 930 N. University Ave, Ann Arbor, MI 48109, USA.
| | - Corey R J Stephenson
- Department of Chemistry, University of Michigan, 930 N. University Ave, Ann Arbor, MI 48109, USA.
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9
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Péter Á, Agasti S, Knowles O, Pye E, Procter DJ. Recent advances in the chemistry of ketyl radicals. Chem Soc Rev 2021; 50:5349-5365. [PMID: 33972956 PMCID: PMC8111543 DOI: 10.1039/d0cs00358a] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ketyl radicals are valuable reactive intermediates for synthesis and are used extensively to construct complex, functionalized products from carbonyl substrates. Single electron transfer (SET) reduction of the C
Created by potrace 1.16, written by Peter Selinger 2001-2019
]]>
O bond of aldehydes and ketones is the classical approach for the formation of ketyl radicals and metal reductants are the archetypal reagents employed. The past decade has, however, witnessed significant advances in the generation and harnessing of ketyl radicals. This tutorial review highlights recent, exciting developments in the chemistry of ketyl radicals by comparing the varied contemporary – for example, using photoredox catalysts – and more classical approaches for the generation and use of ketyl radicals. The review will focus on different strategies for ketyl radical generation, their creative use in new synthetic protocols, strategies for the control of enantioselectivity, and detailed mechanisms where appropriate. Ketyl radicals are valuable reactive intermediates for synthesis. This review highlights exciting recent developments in the chemistry of ketyl radicals by comparing contemporary and more classical approaches for their generation and use.![]()
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Affiliation(s)
- Áron Péter
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, UK.
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10
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Dibrell SE, Tao Y, Reisman SE. Synthesis of Complex Diterpenes: Strategies Guided by Oxidation Pattern Analysis. Acc Chem Res 2021; 54:1360-1373. [PMID: 33621061 DOI: 10.1021/acs.accounts.0c00858] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
With complex molecular architectures, intriguing oxidation patterns, and wide-ranging biological activities, diterpene natural products have greatly impacted research in organic chemistry and drug discovery. Our laboratory has completed total syntheses of several highly oxidized diterpenes, including the ent-kauranoids maoecrystal Z, trichorabdal A, and longikaurin E; the antibiotic pleuromutilin; and the insecticides ryanodol, ryanodine, and perseanol. In this Account, we show how analysis of oxidation patterns and inherent functional group relationships can inform key C-C bond disconnections that greatly simplify the complexity of polycyclic structures and streamline their total syntheses. In articulating these concepts, we draw heavily from the approaches to synthetic strategy that were codified by Evans, Corey, Seebach, and others, based on the formalism that heteroatoms impose an alternating acceptor and donor reactivity pattern upon a carbon skeleton. We find these ideas particularly useful when considering oxidized diterpenes as synthetic targets.In the first part of the Account, we describe the use of reductive cyclizations as strategic tactics for building polycyclic systems with γ-hydroxyketone motifs. We have leveraged Sm-ketyl radical cyclizations as "reactivity umpolungs" to generate γ-hydroxyketones in our total syntheses of the Isodon ent-kauranoid diterpenes (-)-maoecrystal Z, (-)-longikaurin E, and (-)-trichorabdal A. Following this work, we identified the same γ-hydroxyketone pattern in the diterpene antibiotic (+)-pleuromutilin, which again inspired the use of a SmI2-mediated reductive cyclization, this time to construct a bridging eight-membered ring. This collection of four total syntheses highlights how reductive cyclizations are particularly effective umpolung tactics when used to simultaneously form rings and introduce 1,4-dioxygenation patterns.In the second part of the Account, we detail the syntheses of the complex and highly oxidized ryanodane and isoryanodane diterpenes and present the oxidation pattern analysis that guided our synthetic designs. We first discuss our 15-step total synthesis of (+)-ryanodol, which incorporated five of the eight oxygen atoms in just two transformations: a dihydroxylation of (S)-pulegone and a SeO2-mediated trioxidation of the A-ring cyclopentenone. This latter transformation gave rise to an independent investigation of SeO2-mediated peroxidations of simple bicyclic cyclopent-2-en-1-ones. The syntheses of (+)-ryanodine and (+)-20-deoxyspiganthine are also presented, which required modified end-game strategies to selectively incorporate the key pyrrole-2-carboxylate ester. Finally, we describe our fragment coupling approach to prepare the isoryanodane diterpene (+)-perseanol. Using a similar oxidation pattern analysis to that developed in the synthesis of ryanodol, we again identified a two-stage strategy to install the five hydroxyl groups. This strategy was enabled by a Pd-mediated carbopalladation/carbonylation cascade and leveraged unexpected, emergent reactivity to sequence a series of late-stage oxidations.While each of the diterpene natural products discussed in this Account present unique synthetic questions, we hope that through their collective discussion, we provide a conceptual framework that condenses and summarizes the chemical knowledge we have learned and inspires future discourse and innovations in strategy design and methodology development.
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Affiliation(s)
- Sara E. Dibrell
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Yujia Tao
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Sarah E. Reisman
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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11
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Agasti S, Beattie NA, McDouall JJW, Procter DJ. SmI 2-Catalyzed Intermolecular Coupling of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation and Reactivity. J Am Chem Soc 2021; 143:3655-3661. [PMID: 33629852 PMCID: PMC8028054 DOI: 10.1021/jacs.1c01356] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The archetypal single electron transfer reductant, samarium(II) diiodide (SmI2, Kagan's reagent), remains one of the most important reducing agents and mediators of radical chemistry after four decades of widespread use in synthesis. While the chemistry of SmI2 is very often unique, and thus the reagent is indispensable, it is almost invariably used in superstoichiometric amounts, thus raising issues of cost and waste. Of the few reports of the use of catalytic SmI2, all require the use of superstoichiometric amounts of a metal coreductant to regenerate Sm(II). Here, we describe a SmI2-catalyzed intermolecular radical coupling of aryl cyclopropyl ketones and alkynes. The process shows broad substrate scope and delivers a library of decorated cyclopentenes with loadings of SmI2 as low as 15 mol %. The radical relay strategy negates the need for a superstoichiometric coreductant and additives to regenerate SmI2. Crucially, our study uncovers an intriguing link between ketone conformation and efficient cross-coupling and thus provides an insight into the mechanism of radical relays involving SmI2. The study lays further groundwork for the future use of the classical reagent SmI2 in contemporary radical catalysis.
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Affiliation(s)
- Soumitra Agasti
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Nicholas A Beattie
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Joseph J W McDouall
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - David J Procter
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
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12
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Hsu IT, Tomanik M, Herzon SB. Metric-Based Analysis of Convergence in Complex Molecule Synthesis. Acc Chem Res 2021; 54:903-916. [PMID: 33523640 DOI: 10.1021/acs.accounts.0c00817] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Convergent syntheses are characterized by the coupling of two or more synthetic intermediates of similar complexity, often late in a pathway. At its limit, a fully convergent synthesis is achieved when commercial or otherwise readily available intermediates are coupled to form the final target in a single step. Of course, in all but exceptional circumstances this level of convergence is purely hypothetical; in practice, additional steps are typically required to progress from fragment coupling to the target. Additionally, the length of the sequence required to access each target is a primary consideration in synthetic design.In this Account, we provide an overview of alkaloid, polyketide, and diterpene metabolites synthesized in our laboratory and present parameters that may be used to put the degree of convergence of each synthesis on quantitative footing. We begin with our syntheses of the antiproliferative, antimicrobial bacterial metabolite (-)-kinamycin F (1) and related dimeric structure (-)-lomaiviticin aglycon (2). These synthetic routes featured a three-step sequence to construct a complex diazocyclopentadiene found in both targets and an oxidative dimerization to unite the two halves of (-)-lomaiviticin aglycon (2). We then follow with our synthesis of the antineurodegenerative alkaloid (-)-huperzine A (3). Our route to (-)-huperzine A (3) employed a diastereoselective three-component coupling reaction, followed by the intramolecular α-arylation of a β-ketonitrile intermediate, to form the carbon skeleton of the target. We then present our syntheses of the hasubanan alkaloids (-)-hasubanonine (4), (-)-delavayine (5), (-)-runanine (6), (+)-periglaucine B (7), and (-)-acutumine (8). These alkaloids bear a 7-azatricyclo[4.3.3.01,6]dodecane (propellane) core and a highly oxidized cyclohexenone ring. The propellane structure was assembled by the addition of an aryl acetylide to a complex iminium ion, followed by intramolecular 1,4-addition. We then present our synthesis of the guanidinium alkaloid (+)-batzelladine B (9), which contains two complex polycyclic guanidine residues united by an ester linkage. This target was logically disconnected by an esterification to allow for the independent synthesis of each guanidine residue. A carefully orchestrated cascade reaction provided (+)-batzelladine B (9) in a single step following fragment coupling by esterification. We then discuss our synthesis of the diterpene fungal metabolite (+)-pleuromutilin (10). The synthesis of (+)-pleuromutilin (10) proceeded via a fragment coupling involving two neopentylic reagents and employed a nickel-catalyzed reductive cyclization reaction to close the eight-membered ring, ultimately providing access to (+)-pleuromutilin (10), (+)-12-epi-pleuromutilin (11), and (+)-12-epi-mutilin (12). Finally, we discuss our synthesis of (-)-myrocin G (13), a tricyclic pimarane diterpene that was assembled by a convergent annulation.In the final section of this Account, we present several paramaters to analyze and quantitatively assess the degree of convergence of each synthesis. These parameters include: (1) the number of steps required following the point of convergence, (2) the difference in the number of steps required to prepare each coupling partner, (3) the percentage of carbons (or, more broadly, atoms) present at the point of convergence, and (4) the complexity generated in the fragment coupling step. While not an exhaustive list, these parameters bring the strengths and weaknesses each synthetic strategy to light, emphasizing the key contributors to the degree of convergence of each route while also highlighting the nuances of these analyses.
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Affiliation(s)
- Ian Tingyung Hsu
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Martin Tomanik
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Seth B. Herzon
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
- Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut 06520, United States
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13
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Komine K, Lambert KM, Savage QR, Cox JB, Wood JL. Synthetic studies toward longeracemine: a SmI 2-mediated spirocyclization and rearrangement cascade to construct the 2-azabicyclo[2.2.1]heptane framework. Chem Sci 2020; 11:9488-9493. [PMID: 34094215 PMCID: PMC8162136 DOI: 10.1039/d0sc03422c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Longeracemine, a member of the Daphniphyllum family of alkaloids contains a novel carbon framework featuring a highly functionalized 2-azabicyclo[2.2.1]heptane core as part of an overall 5/6/5/5/6/5 skeleton. A synthetic intermediate containing the core of longeracemine has been efficiently prepared by employing a stereoselective SmI2-mediated cascade reaction to advance a 7-azabicyclo[2.2.1]heptadiene to a 2-azabicyclo[2.2.1]heptene that is functionally poised for conversion to the natural product.
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Affiliation(s)
- Keita Komine
- Department of Chemistry and Biochemistry, Baylor University One Bear Place 97348 Waco TX 76798 USA
| | - Kyle M. Lambert
- Department of Chemistry and Biochemistry, Baylor UniversityOne Bear Place 97348WacoTX 76798USA
| | - Quentin R. Savage
- Department of Chemistry and Biochemistry, Baylor UniversityOne Bear Place 97348WacoTX 76798USA
| | - Joshua B. Cox
- Department of Chemistry and Biochemistry, Baylor UniversityOne Bear Place 97348WacoTX 76798USA
| | - John L. Wood
- Department of Chemistry and Biochemistry, Baylor UniversityOne Bear Place 97348WacoTX 76798USA
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14
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Hu YJ, Li LX, Han JC, Min L, Li CC. Recent Advances in the Total Synthesis of Natural Products Containing Eight-Membered Carbocycles (2009-2019). Chem Rev 2020; 120:5910-5953. [PMID: 32343125 DOI: 10.1021/acs.chemrev.0c00045] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Natural products containing eight-membered carbocycles constitute a class of structurally intriguing and biologically important molecules such as the famous diterpenes taxol and vinigrol. Such natural products are being increasingly investigated because of their fascinating architectural features and potent medicinal properties. However, synthesis of natural products with cyclooctane moieties has proved to be highly challenging. This review highlights the recently completed total syntheses of natural products with eight-membered carbocycles with a focus on strategic considerations. A collection of 27 representative studies from the literature covering the decade from 2009 to 2019 is described in chronological order with relevant studies grouped together, including syntheses of the same natural product by different research groups using different strategies. Finally, a summary and outlook including a discussion of the major features of each strategy used in the syntheses are presented. This review illustrates the diversity and creativity in the elegant synthetic designs of eight-membered carbocycles. We hope this review will provide timely illumination and beneficial guidance for future synthetic efforts for organic chemists who are interested in this area.
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Affiliation(s)
- Ya-Jian Hu
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Li-Xuan Li
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Jing-Chun Han
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Long Min
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Chuang-Chuang Li
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
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15
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Wang Z. Construction of all-carbon quaternary stereocenters by catalytic asymmetric conjugate addition to cyclic enones in natural product synthesis. Org Chem Front 2020. [DOI: 10.1039/d0qo00763c] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This review discusses the construction of all-carbon quaternary stereocenters using catalytic asymmetric conjugate addition and its application in natural product synthesis.
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Affiliation(s)
- Zhuo Wang
- Southern University of Science and Technology
- School of Medicine
- Shenzhen
- People's Republic of China
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16
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Beemelmanns C, Nitsch D, Bentz C, Reissig HU. Stereoselective Cascade Cyclizations with Samarium Diiodide to Tetracyclic Indolines: Precursors of Fluorostrychnines and Brucine. Chemistry 2019; 25:8780-8789. [PMID: 31033048 DOI: 10.1002/chem.201900087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/25/2019] [Indexed: 12/16/2022]
Abstract
A series of γ-indolylketones with fluorine, cyano or alkoxy substituents at the benzene moiety was prepared and subjected to samarium diiodide-promoted cyclization reactions. The desired dearomatizing ketyl cascade reaction forming two new rings proceeded in all cases with high diastereoselectivity, but with differing product distribution. In most cases, the desired annulated tetracyclic compounds were obtained in moderate to good yields, but as second product tetracyclic spirolactones were isolated in up to 29 % yield. The reaction rate was influenced by the substituents at the benzene moiety of the substrate as expected, with electron-accepting groups accelerating and electron-donating groups decelerating the cyclization process. In case of a difluoro-substituted γ-indolylketone a partial defluorination was observed. The intermediate samarium enolate of the tetracyclic products could be trapped by adding reactive alkylating agents as electrophiles delivering products with quarternary carbons. In the case of a dimethoxy-substituted tetracyclic cyclization product a subsequent reductive amination stereoselectively provided a pentacyclic compound that was subsequently N-protected and subjected to a regioselective elimination. The obtained functionalized pentacyclic product should be convertible into the alkaloid brucine by four well-established steps. Overall, the presented report shows that functionalized tetracyclic compounds with different substituents are rapidly available with the samarium diiodide cascade cyclization as crucial step. Hence, analogues of the landmark alkaloid strychnine, for example, with specific fluorine substitutions, should be easily accessible.
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Affiliation(s)
- Christine Beemelmanns
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195, Berlin, Germany.,Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie, Beutenbergstraße 11a, 07745, Jena, Germany
| | - Dominik Nitsch
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195, Berlin, Germany
| | - Christoph Bentz
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195, Berlin, Germany
| | - Hans-Ulrich Reissig
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195, Berlin, Germany
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17
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Huffman BJ, Shenvi RA. Natural Products in the "Marketplace": Interfacing Synthesis and Biology. J Am Chem Soc 2019; 141:3332-3346. [PMID: 30682249 PMCID: PMC6446556 DOI: 10.1021/jacs.8b11297] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Drugs are discovered through the biological screening of collections of compounds, followed by optimization toward functional end points. The properties of screening collections are often balanced between diversity, physicochemical favorability, intrinsic complexity, and synthetic tractability (Huggins, D. J.; et al. ACS Chem. Biol. 2011, 6, 208; DOI: 10.1021/cb100420r ). Whereas natural product (NP) collections excel in the first three attributes, NPs suffer a disadvantage on the last point. Academic total synthesis research has worked to solve this problem by devising syntheses of NP leads, diversifying late-stage intermediates, or derivatizing the NP target. This work has led to the discovery of reaction mechanisms, the invention of new methods, and the development of FDA-approved drugs. Few drugs, however, are themselves NPs; instead, NP analogues predominate. Here we highlight past examples of NP analogue development and successful NP-derived drugs. More recently, chemists have explored how NP analogues alter the retrosynthetic analysis of complex scaffolds, merging structural design and synthetic design. This strategy maintains the intrinsic complexity of the NP but can alter the physicochemical properties of the scaffold, like core instability that renders the NP a poor chemotype. Focused libraries based on these syntheses may exclude the NP but maintain the molecular properties that distinguish NP space from synthetic space (Stratton, C. F.; et al. Bioorg. Med. Chem. Lett. 2015, 25, 4802; DOI: 10.1016/j.bmcl.2015.07.014 ), properties that have statistical advantages in clinical progression (Luker, T.; et al. Bioorg. Med. Chem. Lett. 2011, 21, 5673, DOI: 10.1016/j.bmcl.2011.07.074 ; Ritchie, T. J.; Macdonald, S. J. F. Drug Discovery Today 2009, 14, 1011, DOI: 10.1016/j.drudis.2009.07.014 ). Research that expedites synthetic access to NP motifs can prevent homogeneity of chemical matter available for lead discovery. Easily accessed, focused libraries of NP scaffolds can fill empty but active gaps in screening sets and expand the molecular diversity of synthetic collections.
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Affiliation(s)
- Benjamin J. Huffman
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Ryan A. Shenvi
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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18
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19
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Goethe O, Heuer A, Ma X, Wang Z, Herzon SB. Antibacterial properties and clinical potential of pleuromutilins. Nat Prod Rep 2019; 36:220-247. [PMID: 29979463 DOI: 10.1039/c8np00042e] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Covering: up to 2018Pleuromutilins are a clinically validated class of antibiotics derived from the fungal diterpene (+)-pleuromutilin (1). Pleuromutilins inhibit bacterial protein synthesis by binding to the peptidyl transferase center (PTC) of the ribosome. In this review we summarize the biosynthesis and recent total syntheses of (+)-pleuromutilin (1). We review the mode of interaction of pleuromutilins with the bacterial ribosome, which involves binding of the C14 extension and the tricyclic core to the P and A sites of the PTC, respectively. We provide an overview of existing clinical agents, and discuss the three primary modes of bacterial resistance (mutations in ribosomal protein L3, Cfr methylation, and efflux). Finally we collect structure-activity relationships from publicly available reports, and close with some forward looking statements regarding future development.
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Affiliation(s)
- Olivia Goethe
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA.
| | - Abigail Heuer
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA.
| | - Xiaoshen Ma
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA.
| | - Zhixun Wang
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA.
| | - Seth B Herzon
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA. and Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut 06520, USA
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20
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McCombie SW, Quiclet-Sire B, Zard SZ. Reflections on the mechanism of the Barton-McCombie Deoxygenation and on its consequences†. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.03.042] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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21
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Zhang ZS, Huang YZ, Luo J, Jin Z, Liu YH, Tang YZ. Synthesis and antibacterial activities of novel pleuromutilin derivatives bearing an aminothiophenol moiety. Chem Biol Drug Des 2018; 92:1627-1637. [PMID: 29722184 DOI: 10.1111/cbdd.13328] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/18/2018] [Accepted: 03/29/2018] [Indexed: 12/30/2022]
Abstract
We synthesized a series of novel thioether pleuromutilin derivatives incorporating 2-aminothiophenol moieties into the C14 side chain via acylation reactions under mild conditions. We evaluated the in-vitro antibacterial activities of the derivatives against methicillin-resistant Staphylococcus aureus (MRSA, ATCC 43300), Staphylococcus aureus (ATCC 29213) and Escherichia coli (ATCC 25922). The majority of the synthesized derivatives possessed moderate antibacterial activities. Compound 8 was found to be the most active antibacterial derivative against MRSA. We conducted docking experiments to understand the possible mode of interactions between compounds 8, 9b, 11a and 50S ribosomal subunit. The docking results proved that there is a reasonable correlation between the binding free energy and the antibacterial activity. Compound 8 was evaluated for its in-vivo antibacterial activity and showed higher efficacy than tiamulin against MRSA in mouse infection model.
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Affiliation(s)
- Zhao-Sheng Zhang
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Yun-Zhen Huang
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Jian Luo
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Zhen Jin
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Ya-Hong Liu
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - You-Zhi Tang
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
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22
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Huang HM, McDouall JJW, Procter DJ. Radical Anions from Urea-type Carbonyls: Radical Cyclizations and Cyclization Cascades. Angew Chem Int Ed Engl 2018; 57:4995-4999. [PMID: 29493858 DOI: 10.1002/anie.201800667] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Indexed: 11/12/2022]
Affiliation(s)
- Huan-Ming Huang
- School of Chemistry; University of Manchester; Oxford Road Manchester M13 9PL UK
| | | | - David J. Procter
- School of Chemistry; University of Manchester; Oxford Road Manchester M13 9PL UK
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23
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Huang HM, McDouall JJW, Procter DJ. Radical Anions from Urea-type Carbonyls: Radical Cyclizations and Cyclization Cascades. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201800667] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Huan-Ming Huang
- School of Chemistry; University of Manchester; Oxford Road Manchester M13 9PL UK
| | | | - David J. Procter
- School of Chemistry; University of Manchester; Oxford Road Manchester M13 9PL UK
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24
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Morrill C, Jensen C, Just-Baringo X, Grogan G, Turner NJ, Procter DJ. Biocatalytic Conversion of Cyclic Ketones Bearing α-Quaternary Stereocenters into Lactones in an Enantioselective Radical Approach to Medium-Sized Carbocycles. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201800121] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Charlotte Morrill
- School of Chemistry; University of Manchester; Manchester M13 9PL UK
| | - Chantel Jensen
- School of Chemistry; University of Manchester; Manchester M13 9PL UK
| | | | - Gideon Grogan
- Department of Chemistry; University of York, Heslington; York YO10 5DD UK
| | | | - David J. Procter
- School of Chemistry; University of Manchester; Manchester M13 9PL UK
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25
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Morrill C, Jensen C, Just-Baringo X, Grogan G, Turner NJ, Procter DJ. Biocatalytic Conversion of Cyclic Ketones Bearing α-Quaternary Stereocenters into Lactones in an Enantioselective Radical Approach to Medium-Sized Carbocycles. Angew Chem Int Ed Engl 2018; 57:3692-3696. [PMID: 29393988 PMCID: PMC6055628 DOI: 10.1002/anie.201800121] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Indexed: 01/11/2023]
Abstract
Cyclic ketones bearing α‐quaternary stereocenters underwent efficient kinetic resolution using cyclohexanone monooxygenase (CHMO) from Acinetobacter calcoaceticus. Lactones possessing tetrasubstituted stereocenters were obtained with high enantioselectivity (up to >99 % ee) and complete chemoselectivity. Preparative‐scale biotransformations were exploited in conjunction with a SmI2‐mediated cyclization process to access complex, enantiomerically enriched cycloheptan‐ and cycloctan‐1,4‐diols. In a parallel approach to structurally distinct products, enantiomerically enriched ketones from the resolution with an α‐quaternary stereocenter were used in a SmI2‐mediated cyclization process to give cyclobutanol products (up to >99 % ee).
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Affiliation(s)
- Charlotte Morrill
- School of Chemistry, University of Manchester, Manchester, M13 9PL, UK
| | - Chantel Jensen
- School of Chemistry, University of Manchester, Manchester, M13 9PL, UK
| | | | - Gideon Grogan
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
| | - Nicholas J Turner
- School of Chemistry, University of Manchester, Manchester, M13 9PL, UK
| | - David J Procter
- School of Chemistry, University of Manchester, Manchester, M13 9PL, UK
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26
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Hung K, Hu X, Maimone TJ. Total synthesis of complex terpenoids employing radical cascade processes. Nat Prod Rep 2018; 35:174-202. [PMID: 29417970 PMCID: PMC5858714 DOI: 10.1039/c7np00065k] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Covering: 2011-2017Radical cyclizations have a rich history in organic chemistry and have been particularly generous to the field of natural product synthesis. Owing to their ability to operate in highly congested molecular quarters, and with significant functional group compatibility, these transformations have enabled the synthesis of numerous polycyclic terpenoid natural products over the past several decades. Moreover, when programmed accordingly into a synthetic plan, radical cascade processes can be used to rapidly assemble molecular complexity, much in the same way nature rapidly constructs terpene frameworks through cationic cyclization pathways. This review highlights recent total syntheses of complex terpenoids (from 2011-2017) employing C-C bond-forming radical cascade sequences.
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Affiliation(s)
- Kevin Hung
- Department of Chemistry, University of California - Berkeley, Berkeley, CA 94720, USA.
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27
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Narita K, Minami A, Ozaki T, Liu C, Kodama M, Oikawa H. Total Biosynthesis of Antiangiogenic Agent (-)-Terpestacin by Artificial Reconstitution of the Biosynthetic Machinery in Aspergillus oryzae. J Org Chem 2018; 83:7042-7048. [PMID: 29417814 DOI: 10.1021/acs.joc.7b03220] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The total biosynthesis of (-)-terpestacin was achieved by heterologous expression of four biosynthetic enzyme genes ( tpcA- D) in Aspergillus oryzae. After construction of preterpestacin I by the action of bifunctional terpene synthase (TpcA), two cytochrome P450s (TpcBC) activate inert C-H bond to install three hydroxyl groups on the A-ring in stereo- and regioselective manners. Subsequently, a flavin-dependent oxidase (TpcD) catalyzes oxidation of the vicinal diol moiety to give a α-diketone, which undergoes an enolization to furnish terpestacin. The successful synthesis of structurally elaborated terpestacin showed that a reconstitution approach that harnesses several biosynthetic enzyme genes in A. oryzae could be a promising alternative to the current chemical synthesis of natural terpenoids.
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Affiliation(s)
- Koji Narita
- Division of Chemistry, Graduate School of Science , Hokkaido University , Sapporo 060-0810 , Japan
| | - Atsushi Minami
- Division of Chemistry, Graduate School of Science , Hokkaido University , Sapporo 060-0810 , Japan
| | - Taro Ozaki
- Division of Chemistry, Graduate School of Science , Hokkaido University , Sapporo 060-0810 , Japan
| | - Chengwei Liu
- Division of Chemistry, Graduate School of Science , Hokkaido University , Sapporo 060-0810 , Japan
| | - Motoichiro Kodama
- Faculty of Agriculture , Tottori University , Tottori 680-8553 , Japan
| | - Hideaki Oikawa
- Division of Chemistry, Graduate School of Science , Hokkaido University , Sapporo 060-0810 , Japan
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28
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Abstract
An 18-step synthesis of the antibiotic (+)-pleuromutilin is disclosed. The key steps of the synthesis include a highly stereoselective SmI2-mediated cyclization to establish the eight-membered ring and a stereospecific transannular [1,5]-hydrogen atom transfer to set the C10 stereocenter. This strategy was also used to prepare (+)-12-epi-pleuromutilin. The chemistry described here will enable efforts to prepare new mutilin antibiotics.
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Affiliation(s)
| | | | - Felix Schäfers
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Sarah E. Reisman
- The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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29
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Affiliation(s)
- Masaya Nakajima
- Graduate School of Pharmaceutical Sciences, Chiba University
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30
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Yamane M, Minami A, Liu C, Ozaki T, Takeuchi I, Tsukagoshi T, Tokiwano T, Gomi K, Oikawa H. Biosynthetic Machinery of Diterpene Pleuromutilin Isolated from Basidiomycete Fungi. Chembiochem 2017; 18:2317-2322. [PMID: 28924980 DOI: 10.1002/cbic.201700434] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Indexed: 12/11/2022]
Abstract
The diterpene pleuromutilin is a ribosome-targeting antibiotic isolated from basidiomycete fungi, such as Clitopilus pseudo-pinsitus. The functional characterization of all biosynthetic enzymes involved in pleuromutilin biosynthesis is reported and a biosynthetic pathway proposed. In vitro enzymatic reactions and mutational analysis revealed that a labdane-related diterpene synthase, Ple3, catalyzed two rounds of cyclization from geranylgeranyl diphosphate to premutilin possessing a characteristic 5-6-8-tricyclic carbon skeleton. Biotransformation experiments utilizing Aspergillus oryzae transformants possessing modification enzyme genes allowed the biosynthetic pathway from premutilin to pleuromutilin to be proposed. The present study sets the stage for the enzymatic synthesis of natural products isolated from basidiomycete fungi, which are a prolific source of structurally diverse and biologically active terpenoids.
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Affiliation(s)
- Momoka Yamane
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Atsushi Minami
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Chengwei Liu
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Taro Ozaki
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Ichiro Takeuchi
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Tae Tsukagoshi
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Tetsuo Tokiwano
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Katsuya Gomi
- Graduate School of Agricultural Science, Tohoku University, Sendai, 981-8555, Japan
| | - Hideaki Oikawa
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, 060-0810, Japan
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31
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Zeng M, Murphy SK, Herzon SB. Development of a Modular Synthetic Route to (+)-Pleuromutilin, (+)-12-epi-Mutilins, and Related Structures. J Am Chem Soc 2017; 139:16377-16388. [PMID: 29048164 PMCID: PMC7024634 DOI: 10.1021/jacs.7b09869] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We describe the development of an enantioselective synthetic route to (+)-pleuromutilin (1), (+)-12-epi-mutilin, and related derivatives. A key hydrindanone was prepared in three steps and 48% overall yield from cyclohex-2-en-1-one. 1,4-Hydrocyanation provided a nitrile (53%, or 85% based on recovered starting material) that was converted to the eneimide 57 in 80% yield by the 1,2-addition of methyllithium to the nitrile function, cyclization, and in situ acylation with di-tert-butyldicarbonate. The eneimide 57 was employed in a 2-fold neopentylic coupling reaction with an organolithium reagent derived from the alkyl iodides (R)- or (S)-30, which contain the C11-C13 atoms of the target, to provide diastereomeric diketones in 60% or 48% yield (for coupling with (R)- or (S)-30, respectively). The diketone derived from (S)-30 contains the (S)-C12 stereochemistry found in pleuromutilin and was elaborated to an alkynylaldehyde. Nickel-catalyzed reductive cyclization of this alkynylaldehyde, to construct the eight-membered ring of the target, unexpectedly provided a cyclopentene (67%), which arises from participation of the C12-α-olefin in the transformation. The diketone derived from the enantiomeric C12-fragment (R)-30 underwent reductive cyclization to provide the desired product in 60% yield. This was elaborated to 12-epi-mutilin by a four-step sequence (39% overall). Installation of the glycolic acid residue followed by C12 epimerization (Berner et al. Monatsh. Chem. 1986, 117, 1073) generated (+)-pleuromutilin (1). (+)-12-epi-Pleuromutilin and (+)-11,12-di-epi-pleuromutilin were prepared by related sequences. This work establishes a convergent entry to the pleuromutilins and provides a foundation for the production of novel antibiotics to treat drug-resistant and Gram-negative infections.
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Affiliation(s)
- Mingshuo Zeng
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Stephen K. Murphy
- Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut 06520, United States
| | - Seth B. Herzon
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
- Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut 06520, United States
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32
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Plesniak MP, Huang HM, Procter DJ. Radical cascade reactions triggered by single electron transfer. Nat Rev Chem 2017. [DOI: 10.1038/s41570-017-0077] [Citation(s) in RCA: 169] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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33
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Murphy SK, Zeng M, Herzon SB. Scalable Synthesis of a Key Intermediate for the Production of Pleuromutilin-Based Antibiotics. Org Lett 2017; 19:4980-4983. [PMID: 28858512 PMCID: PMC7001007 DOI: 10.1021/acs.orglett.7b02476] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An improved synthesis of an eneimide, which is a useful precursor to pleuromutilin-based antibiotics, is reported. This synthesis proceeds in six steps and 17% overall yield (27% based on recovery of a key hydrindenone intermediate) and requires two fewer chromatography steps and five fewer days of reaction time than the previously reported route. The use of expensive, acutely toxic, and precious metal reagents or catalysts has been minimized.
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Affiliation(s)
- Stephen K. Murphy
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Mingshuo Zeng
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Seth B. Herzon
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
- Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut 06520, United States
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34
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A brief history of antibiotics and select advances in their synthesis. J Antibiot (Tokyo) 2017; 71:153-184. [DOI: 10.1038/ja.2017.62] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 04/17/2017] [Accepted: 04/23/2017] [Indexed: 12/20/2022]
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35
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Huq SR, Shi S, Diao R, Szostak M. Mechanistic Study of SmI2/H2O and SmI2/Amine/H2O-Promoted Chemoselective Reduction of Aromatic Amides (Primary, Secondary, Tertiary) to Alcohols via Aminoketyl Radicals. J Org Chem 2017. [DOI: 10.1021/acs.joc.7b00372] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Syed R. Huq
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Shicheng Shi
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Ray Diao
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Michal Szostak
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
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36
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Murphy SK, Zeng M, Herzon SB. A modular and enantioselective synthesis of the pleuromutilin antibiotics. Science 2017; 356:956-959. [PMID: 28572392 PMCID: PMC7001679 DOI: 10.1126/science.aan0003] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 04/25/2017] [Indexed: 12/20/2022]
Abstract
The tricyclic diterpene fungal metabolite (+)-pleuromutilin has served as a starting point for antibiotic development. Semisynthetic modification of its glycolic acid subunit at C14 provided the first analogs fit for human use, and derivatization at C12 led to 12-epi-pleuromutilins with extended-spectrum antibacterial activity, including activity against Gram-negative pathogens. Given the inherent limitations of semisynthesis, however, accessing derivatives of (+)-pleuromutilin with full control over their structure presents an opportunity to develop derivatives with improved antibacterial activities. Here we disclose a modular synthesis of pleuromutilins by the convergent union of an enimide with a bifunctional iodoether. We illustrate our approach through synthesis of (+)-12-epi-mutilin, (+)-11,12-di-epi-mutilin, (+)-12-epi-pleuromutilin, (+)-11,12-di-epi-pleuromutilin, and (+)-pleuromutilin itself in 17 to 20 steps.
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Affiliation(s)
- Stephen K Murphy
- Department of Chemistry, Yale University, New Haven, CT 06520, USA
| | - Mingshuo Zeng
- Department of Chemistry, Yale University, New Haven, CT 06520, USA
| | - Seth B Herzon
- Department of Chemistry, Yale University, New Haven, CT 06520, USA.
- Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520, USA
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37
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Alberti F, Foster GD, Bailey AM. Natural products from filamentous fungi and production by heterologous expression. Appl Microbiol Biotechnol 2017; 101:493-500. [PMID: 27966047 PMCID: PMC5219032 DOI: 10.1007/s00253-016-8034-2] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/22/2016] [Accepted: 11/25/2016] [Indexed: 01/07/2023]
Abstract
Filamentous fungi represent an incredibly rich and rather overlooked reservoir of natural products, which often show potent bioactivity and find applications in different fields. Increasing the naturally low yields of bioactive metabolites within their host producers can be problematic, and yield improvement is further hampered by such fungi often being genetic intractable or having demanding culturing conditions. Additionally, total synthesis does not always represent a cost-effective approach for producing bioactive fungal-inspired metabolites, especially when pursuing assembly of compounds with complex chemistry. This review aims at providing insights into heterologous production of secondary metabolites from filamentous fungi, which has been established as a potent system for the biosynthesis of bioactive compounds. Numerous advantages are associated with this technique, such as the availability of tools that allow enhanced production yields and directing biosynthesis towards analogues of the naturally occurring metabolite. Furthermore, a choice of hosts is available for heterologous expression, going from model unicellular organisms to well-characterised filamentous fungi, which has also been shown to allow the study of biosynthesis of complex secondary metabolites. Looking to the future, fungi are likely to continue to play a substantial role as sources of new pharmaceuticals and agrochemicals-either as producers of novel natural products or indeed as platforms to generate new compounds through synthetic biology.
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Affiliation(s)
- Fabrizio Alberti
- School of Life Sciences and Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL UK
| | - Gary D. Foster
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
| | - Andy M. Bailey
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
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38
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Huang HM, Bonilla P, Procter DJ. Selective construction of quaternary stereocentres in radical cyclisation cascades triggered by electron-transfer reduction of amide-type carbonyls. Org Biomol Chem 2017; 15:4159-4164. [DOI: 10.1039/c7ob00739f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Radical cyclisation cascades triggered by electron-transfer to amide-type carbonyls using SmI2–H2O–LiBr, result in the selective construction of quaternary carbon stereocentres.
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Affiliation(s)
| | - Pablo Bonilla
- School of Chemistry
- University of Manchester
- Manchester
- UK
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39
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Luo J, Yang QE, Yang YY, Tang YZ, Liu YH. Design, synthesis, and structure-activity relationship studies of novel pleuromutilin derivatives having a piperazine ring. Chem Biol Drug Des 2016; 88:699-709. [PMID: 27273921 DOI: 10.1111/cbdd.12799] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Revised: 05/18/2016] [Accepted: 05/31/2016] [Indexed: 11/29/2022]
Abstract
A series of novel pleuromutilin derivatives possessing piperazine moieties were synthesized under mild conditions. The in vitro antibacterial activities of these derivatives against Staphylococcus aureus and Escherichia coli were tested by the agar dilution method. Structure-activity relationship studies resulted in compounds 11b, 13b, and 14a with the most potent in vitro antibacterial activity among the series (minimal inhibitory concentration = 0.0625-0.125 μg/mL). The binding of compounds 11b, 13b, and 14a to the E. coli ribosome was investigated by molecular modeling, and it was found that there is a reasonable correlation between the binding free energy and the antibacterial activity.
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Affiliation(s)
- Jian Luo
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Qiu-E Yang
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Yuan-Yuan Yang
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - You-Zhi Tang
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.
| | - Ya-Hong Liu
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.
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40
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Yan M, Lo JC, Edwards JT, Baran PS. Radicals: Reactive Intermediates with Translational Potential. J Am Chem Soc 2016; 138:12692-12714. [PMID: 27631602 PMCID: PMC5054485 DOI: 10.1021/jacs.6b08856] [Citation(s) in RCA: 678] [Impact Index Per Article: 84.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Indexed: 02/08/2023]
Abstract
This Perspective illustrates the defining characteristics of free radical chemistry, beginning with its rich and storied history. Studies from our laboratory are discussed along with recent developments emanating from others in this burgeoning area. The practicality and chemoselectivity of radical reactions enable rapid access to molecules of relevance to drug discovery, agrochemistry, material science, and other disciplines. Thus, these reactive intermediates possess inherent translational potential, as they can be widely used to expedite scientific endeavors for the betterment of humankind.
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Affiliation(s)
- Ming Yan
- Department
of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Julian C. Lo
- Department
of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Jacob T. Edwards
- Department
of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Phil S. Baran
- Department
of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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41
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Just-Baringo X, Clark J, Gutmann MJ, Procter DJ. Selective Synthesis of Cyclooctanoids by Radical Cyclization of Seven-Membered Lactones: Neutron Diffraction Study of the Stereoselective Deuteration of a Chiral Organosamarium Intermediate. Angew Chem Int Ed Engl 2016; 55:12499-502. [PMID: 27600354 PMCID: PMC5113801 DOI: 10.1002/anie.201606792] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Indexed: 11/09/2022]
Abstract
Seven-membered lactones undergo selective SmI2 -H2 O-promoted radical cyclization to form substituted cyclooctanols. The products arise from an exo-mode of cyclization rather than the usual endo-attack employed in the few radical syntheses of cyclooctanes. The process is terminated by the quenching of a chiral benzylic samarium. A labeling experiment and neutron diffraction study have been used for the first time to probe the configuration and highly diastereoselective deuteration of a chiral organosamarium intermediate.
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Affiliation(s)
| | - Jemma Clark
- School of Chemistry, University of Manchester, Manchester, M13 9PL, UK
| | - Matthias J Gutmann
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, UK
| | - David J Procter
- School of Chemistry, University of Manchester, Manchester, M13 9PL, UK.
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42
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Just-Baringo X, Clark J, Gutmann MJ, Procter DJ. Selective Synthesis of Cyclooctanoids by Radical Cyclization of Seven-Membered Lactones: Neutron Diffraction Study of the Stereoselective Deuteration of a Chiral Organosamarium Intermediate. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201606792] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | - Jemma Clark
- School of Chemistry; University of Manchester; Manchester M13 9PL UK
| | - Matthias J. Gutmann
- ISIS Facility; Rutherford Appleton Laboratory; Chilton, Didcot Oxfordshire OX11 0QX UK
| | - David J. Procter
- School of Chemistry; University of Manchester; Manchester M13 9PL UK
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43
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Liu J, Bedell TA, West JG, Sorensen EJ. Design and Synthesis of Molecular Scaffolds with Anti-infective Activity. Tetrahedron 2016; 72:3579-3592. [PMID: 27284210 PMCID: PMC4894353 DOI: 10.1016/j.tet.2016.01.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
| | - T. Aaron Bedell
- Department of Chemistry, Princeton University, Frick Chemical Laboratory, Princeton, New Jersey 08544, USA
| | - Julian G. West
- Department of Chemistry, Princeton University, Frick Chemical Laboratory, Princeton, New Jersey 08544, USA
| | - Erik J. Sorensen
- Department of Chemistry, Princeton University, Frick Chemical Laboratory, Princeton, New Jersey 08544, USA
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44
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Huang D, Schuppe AW, Liang MZ, Newhouse TR. Scalable procedure for the fragmentation of hydroperoxides mediated by copper and iron tetrafluoroborate salts. Org Biomol Chem 2016; 14:6197-200. [PMID: 27273761 DOI: 10.1039/c6ob00941g] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
An improved protocol for the formal elimination of propene from organic substrates is reported. This process entails the ozonolytic conversion of an alkene to a methoxy hydroperoxide which undergoes fragmentation mediated by copper and iron. The use of soluble Cu(BF4)2 and Fe(BF4)2 results in reproducible results up to a 100 gram scale.
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Affiliation(s)
- David Huang
- Department of Chemistry, Yale University, 275 Prospect St., New Haven, CT 06520-8107, USA.
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45
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Bailey AM, Alberti F, Kilaru S, Collins CM, de Mattos-Shipley K, Hartley AJ, Hayes P, Griffin A, Lazarus CM, Cox RJ, Willis CL, O’Dwyer K, Spence DW, Foster GD. Identification and manipulation of the pleuromutilin gene cluster from Clitopilus passeckerianus for increased rapid antibiotic production. Sci Rep 2016; 6:25202. [PMID: 27143514 PMCID: PMC4855138 DOI: 10.1038/srep25202] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 04/11/2016] [Indexed: 12/16/2022] Open
Abstract
Semi-synthetic derivatives of the tricyclic diterpene antibiotic pleuromutilin from the basidiomycete Clitopilus passeckerianus are important in combatting bacterial infections in human and veterinary medicine. These compounds belong to the only new class of antibiotics for human applications, with novel mode of action and lack of cross-resistance, representing a class with great potential. Basidiomycete fungi, being dikaryotic, are not generally amenable to strain improvement. We report identification of the seven-gene pleuromutilin gene cluster and verify that using various targeted approaches aimed at increasing antibiotic production in C. passeckerianus, no improvement in yield was achieved. The seven-gene pleuromutilin cluster was reconstructed within Aspergillus oryzae giving production of pleuromutilin in an ascomycete, with a significant increase (2106%) in production. This is the first gene cluster from a basidiomycete to be successfully expressed in an ascomycete, and paves the way for the exploitation of a metabolically rich but traditionally overlooked group of fungi.
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Affiliation(s)
- Andy M. Bailey
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Fabrizio Alberti
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Sreedhar Kilaru
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Catherine M. Collins
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Kate de Mattos-Shipley
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Amanda J. Hartley
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Patrick Hayes
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Alison Griffin
- GSK, Southdownview Way, Worthing, West Sussex, BN14 8QH, UK
| | - Colin M. Lazarus
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Russell J. Cox
- School of Chemistry, University of Bristol, Cantock’s Close Bristol, BS8 1TS, UK
| | - Christine L. Willis
- School of Chemistry, University of Bristol, Cantock’s Close Bristol, BS8 1TS, UK
| | - Karen O’Dwyer
- GSK, 1250 S. Collegeville Road, Collegeville, Pennsylvania, 19426-0989, United States
| | - David W. Spence
- School of Chemistry, University of Bristol, Cantock’s Close Bristol, BS8 1TS, UK
| | - Gary D. Foster
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
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46
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Ruscoe RE, Fazakerley NJ, Huang H, Flitsch S, Procter DJ. Copper-Catalyzed Double Additions and Radical Cyclization Cascades in the Re-Engineering of the Antibacterial Pleuromutilin. Chemistry 2016; 22:116-9. [PMID: 26527052 PMCID: PMC4736435 DOI: 10.1002/chem.201504343] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Indexed: 12/30/2022]
Abstract
A general synthetic sequence involving simply prepared starting materials provides rapid access to diverse, novel tricyclic architectures inspired by pleuromutilin. Sm(II) -mediated radical cyclization cascades of dialdehydes, prepared using a new, one-pot, copper-catalyzed double organomagnesium addition to β-chlorocyclohexenone, proceed with complete sequence selectivity and typically with high diastereocontrol to give analogues of the target core. Our expedient approach (ca. 7 steps) allows non-traditional, de novo synthetic access to analogues of the important antibacterial that can't be prepared from the natural product by semisynthesis.
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Affiliation(s)
- Rebecca E Ruscoe
- School of Chemistry University of Manchester, Oxford Rd, Manchester, M13 9PL (UK)
| | - Neal J Fazakerley
- School of Chemistry University of Manchester, Oxford Rd, Manchester, M13 9PL (UK)
| | - Huanming Huang
- School of Chemistry University of Manchester, Oxford Rd, Manchester, M13 9PL (UK)
| | - Sabine Flitsch
- School of Chemistry University of Manchester, Oxford Rd, Manchester, M13 9PL (UK)
| | - David J Procter
- School of Chemistry University of Manchester, Oxford Rd, Manchester, M13 9PL (UK).
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47
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Shi S, Szostak R, Szostak M. Proton-coupled electron transfer in the reduction of carbonyls using SmI2–H2O: implications for the reductive coupling of acyl-type ketyl radicals with SmI2–H2O. Org Biomol Chem 2016; 14:9151-9157. [DOI: 10.1039/c6ob01621a] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The feasibility of concerted PCET in the reduction of carbonyl groups using SmI2–H2O is quantitatively assessed.
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Affiliation(s)
- Shicheng Shi
- Department of Chemistry
- Rutgers University
- Newark
- USA
| | - Roman Szostak
- Department of Chemistry
- Wroclaw University
- Wroclaw 50-383
- Poland
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48
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Just-Baringo X, Procter DJ. Sm(II)-Mediated Electron Transfer to Carboxylic Acid Derivatives: Development of Complexity-Generating Cascades. Acc Chem Res 2015; 48:1263-75. [PMID: 25871998 DOI: 10.1021/acs.accounts.5b00083] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Reductive electron transfer (ET) to organic compounds is a powerful method for the activation of substrates via the formation of radicals, radical anions, anions, and dianions that can be exploited in bond-cleaving and bond-forming processes. Since its introduction to the synthetic community in 1977 by Kagan, SmI2 has become one of the most important reducing agents available in the laboratory. Despite its widespread application in aldehyde and ketone reduction, it was widely accepted that carboxylic acid derivatives could not be reduced by SmI2; only recently has our work led to this dogma being overturned, and the reduction of carboxylic acid derivatives using SmI2 can now take its place alongside aldehyde/ketone reduction as a powerful activation mode for synthesis. In this Account, we set out our studies of the reduction of carboxylic acid derivatives using SmI2, SmI2-H2O, and SmI2-H2O-NR3 and the exploitation of the unusual radical anions that are now accessible in unprecedented carbon-carbon bond-forming processes. The Account begins with our serendipitous discovery that SmI2 mixed with H2O is able to reduce six-membered lactones to diols, a transformation previously thought to be impossible. After the successful development of selective monoreductions of Meldrum's acid and barbituric acid heterocyclic feedstocks, we then identified the SmI2-H2O-NR3 reagent system for the efficient reduction of a range of acyclic carboxylic acid derivatives that typically present a significant challenge for ET reductants. Mechanistic studies have led us to propose a common mechanism for the reduction of carboxylic acid derivatives using Sm(II), with only subtle changes observed as the carboxylic acid derivative and Sm(II) reagent system are varied. At the center of our postulated mechanism is the proposed reversibility of the first ET to the carbonyl of carboxylic acid derivatives, and this led us to devise several strategies that allow the radical anion intermediates to be exploited productively in efficient new processes. First, we have used internal directing groups in substrates to "switch on" productive ET to esters and amides and have exploited such an approach in tag-removal cyclization processes that deliver molecular scaffolds of significance in biology and materials science. Second, we have exploited external ligands to facilitate ET to carboxylic acid derivatives and have applied the strategy in telescoped reaction sequences. Finally, we have employed follow-up cyclizations with alkenes, alkynes, and allenes to intercept radical anion intermediates formed along the reaction path and have employed this strategy in complexity-generating cascade approaches to biologically significant molecular architectures. From our studies, it is now clear that Sm(II)-mediated ET to carboxylic acid derivatives constitutes a general strategy for inverting the polarity of the carbonyl, allowing nucleophilic carbon-centered radicals to be formed and exploited in novel chemical processes.
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Affiliation(s)
| | - David J. Procter
- School of Chemistry, University of Manchester, Manchester M13 9PL, U.K
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49
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Sirouspour M, Souri S. Synthesis of New Functionalized Heterocyclic [4,3,3] Propellanes via Three-component Reaction Based on Ninhydrin-Phenol Adducts. J Heterocycl Chem 2015. [DOI: 10.1002/jhet.2283] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Mehdi Sirouspour
- Department of Chemistry, Borujerd Branch; Islamic Azad University; Borujerd Iran
| | - Sanaz Souri
- Department of Chemistry, Borujerd Branch; Islamic Azad University; Borujerd Iran
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50
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Shen M, Tu Y, Xie G, Niu Q, Mao H, Xie T, Flowers RA, Lv X, Wang X. Allylsamarium Bromide-Mediated Cascade Cyclization of Homoallylic Esters. Synthesis of 2-(2-Hydroxyalkyl)cyclopropanols and 2-(2-Hydroxyethyl)bicyclo[2.1.1]hexan-1-ols. J Org Chem 2015; 80:52-61. [PMID: 25427109 DOI: 10.1021/jo501797w] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In continuation of our previous study on the intramolecular reductive coupling of simple homoallylic esters promoted by allylSmBr/HMPA/H2O, which afforded a facile synthesis of 2-(2-hydroxyalkyl)cyclopropanols, here we report the reductive cascade cyclization of but-3-enyl but-3-enoates mediated by allylSmBr/HMPA/CuCl2·2H2O, in which the two C═C bonds were successively coupled to allow the construction of the structurally interesting bridged bicyclic tertiary alcohols. Thus, the 2-(2-hydroxyethyl)bicyclo[2.1.1]hexan-1-ols were prepared in moderate to good yields with excellent diastereoselectivity.
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Affiliation(s)
- Mengmeng Shen
- †Department of Chemistry, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, People's Republic of China
| | - Yawei Tu
- †Department of Chemistry, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, People's Republic of China
| | - Guanqun Xie
- †Department of Chemistry, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, People's Republic of China
| | - Qingsheng Niu
- †Department of Chemistry, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, People's Republic of China
| | - Hui Mao
- †Department of Chemistry, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, People's Republic of China
| | - Tingting Xie
- †Department of Chemistry, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, People's Republic of China
| | - Robert A Flowers
- ‡Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Xin Lv
- †Department of Chemistry, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, People's Republic of China
| | - Xiaoxia Wang
- †Department of Chemistry, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, People's Republic of China
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