1
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Hackbarth J, Friestad GK. A Three-Step Catalytic Asymmetric Sequence from Alkynes to α-Silyloxyaldehydes and Its Application to a C22-C41 Fragment of Bastimolide A. Org Lett 2024; 26:4492-4496. [PMID: 38753853 PMCID: PMC11148846 DOI: 10.1021/acs.orglett.4c01310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/07/2024] [Accepted: 05/13/2024] [Indexed: 05/18/2024]
Abstract
1,5-Polyol structures present challenges in stereocontrol, configurational assignment, and diastereomer separation; these are all compromised by remote stereochemical relationships. A configuration-encoded approach with alcohol configurations previously established within enantiopure building blocks offers a versatile solution to these issues. The iterative construction begins with α-silyloxyaldehydes; here, we introduce an enantioselective and step-economical route from alkynes to α-silyloxyaldehydes via silyl cation-induced ring opening of enol ester epoxides. This development enables an efficient configuration-encoded synthesis of the C22-C41 fragment of the bastimolides.
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Affiliation(s)
- Jacob
N. Hackbarth
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Gregory K. Friestad
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
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2
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Mittendorf F, Celik IE, Kirsch SF. Total Synthesis of Cryptoconcatone D via Construction of 1,3-Diol Units Using Chiral Horner-Wittig Reagents. J Org Chem 2022; 87:14899-14908. [PMID: 36195315 DOI: 10.1021/acs.joc.2c01737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The modular synthesis of 1,3-polyols using a chiral phosphine oxide building block is reported. This versatile building block works in a repetitive way for the stereocontrolled synthesis of a tetraol key intermediate, which serves for the first total synthesis of the potentially anti-inflammatory natural product cryptoconcatone D. A new route toward the chiral building block is also presented: Starting from 2-deoxy-d-ribose, the optimized sequence now makes the use of the building block more attractive to practicing chemists again.
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Affiliation(s)
- Fabia Mittendorf
- Organic Chemistry, Bergische Universität Wuppertal, Gaußstr. 20, 42119 Wuppertal, Germany
| | - Ibrahim-Ethem Celik
- Organic Chemistry, Bergische Universität Wuppertal, Gaußstr. 20, 42119 Wuppertal, Germany
| | - Stefan F Kirsch
- Organic Chemistry, Bergische Universität Wuppertal, Gaußstr. 20, 42119 Wuppertal, Germany
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3
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Fiorito D, Keskin S, Bateman JM, George M, Noble A, Aggarwal VK. Stereocontrolled Total Synthesis of Bastimolide B Using Iterative Homologation of Boronic Esters. J Am Chem Soc 2022; 144:7995-8001. [PMID: 35499478 PMCID: PMC9100475 DOI: 10.1021/jacs.2c03192] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Bastimolide B is
a polyhydroxy macrolide isolated from marine cyanobacteria
displaying antimalarial activity. It features a dense array of hydroxylated
stereogenic centers with 1,5-relationships along a hydrocarbon chain.
These 1,5-polyols represent a particularly challenging motif for synthesis,
as the remote position of the stereocenters hampers stereocontrol.
Herein, we present a strategy for 1,5-polyol stereocontrolled synthesis
based on iterative boronic ester homologation with enantiopure magnesium
carbenoids. By merging boronic ester homologation and transition-metal-catalyzed
alkene hydroboration and diboration, the acyclic backbone of bastimolide
B was rapidly assembled from readily available building blocks with
full control over the remote stereocenters, enabling the total synthesis
to be completed in 16 steps (LLS).
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Affiliation(s)
- Daniele Fiorito
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Selbi Keskin
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Joseph M Bateman
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Malcolm George
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Adam Noble
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Varinder K Aggarwal
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
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4
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Friedrich RM, Friestad GK. Inspirations from tetrafibricin and related polyketides: new methods and strategies for 1,5-polyol synthesis. Nat Prod Rep 2020; 37:1229-1261. [PMID: 32412021 DOI: 10.1039/c9np00070d] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Covering: up to 2019 Selective synthesis with control of remote stereogenic centers has long been a challenge in organic chemistry. In recent years the interest in this topic has been energized by isolation and synthetic studies of tetrafibricin and other natural products containing 1,5-polyols, such as amphidinol 3, marinomycins, and caylobolide. Here we discuss recent developments in 1,5-polyol synthesis, including an overview of selected bioactive natural products in this class and examples of new synthetic methodologies and strategies dedicated to remote stereocontrol in these structures. To illustrate in greater depth, we review several instructive examples of how these innovations have been applied in synthetic studies on tetrafibricin.
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Affiliation(s)
- Ryan M Friedrich
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA.
| | - Gregory K Friestad
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA.
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5
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Friedrich RM, Bell JQ, Garcia A, Shen Z, Friestad GK. Unified Strategy for 1,5,9- and 1,5,7-Triols via Configuration-Encoded 1,5-Polyol Synthesis: Preparation and Coupling of C15-C25 and C26-C40 Fragments of Tetrafibricin. J Org Chem 2018; 83:13650-13669. [PMID: 30372076 DOI: 10.1021/acs.joc.8b02034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Diverse classes of natural products contain chiral 1,5,9- and 1,5,7-triol stereotriads, including the novel fibrinogen receptor antagonist tetrafibricin. Biological activities associated with compounds containing these motifs warrant targeted synthetic strategies to 1,5-polyol families from cheap and easily accessible reagents while avoiding the need to determine configurations at each alcohol stereocenter. In the accompanying paper, we present a solution to these problems via an iterative configuration-encoded strategy that exploits Julia-Kocienski couplings of enantiopure α-silyloxy-γ-sulfononitrile building blocks. The stereocontrol is unambiguous, and the building blocks are available in multigram quantities via asymmetric catalysis. This approach efficiently accessed a C26-C40 subunit of tetrafibricin that contains a syn, syn-1,5,9-triol and all of the stereochemistry and functionality needed to advance toward tetrafibricin. A modification afforded the anti, syn-1,5,7-triol within the C15-C25 fragment of tetrafibricin by merging 1,5-polyol synthesis with diastereoselective intramolecular conjugate addition. The union of the C15-C25 and C26-C40 fragments was achieved via a BF3·OEt2-mediated Mukaiyama aldol construction with high 1,3- anti stereoinduction, revealing some unexpected insights on the impact of silyl protecting groups on 1,3- anti diastereocontrol by a β-siloxyaldehyde aldol acceptor. Directed 1,3- anti reduction completed the stereostructure of the C15-C40 portion of tetrafibricin, with configurations established by a combination of NMR experiments.
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Affiliation(s)
- Ryan M Friedrich
- Department of Chemistry , University of Iowa , Iowa City , Iowa 52242 , United States
| | - Jay Q Bell
- Department of Chemistry , University of Iowa , Iowa City , Iowa 52242 , United States
| | - Alfredo Garcia
- Department of Chemistry , University of Iowa , Iowa City , Iowa 52242 , United States
| | - Zican Shen
- Department of Chemistry , University of Iowa , Iowa City , Iowa 52242 , United States
| | - Gregory K Friestad
- Department of Chemistry , University of Iowa , Iowa City , Iowa 52242 , United States
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6
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Friedrich RM, Sreenilayam G, Hackbarth J, Friestad GK. Unified Strategy for 1,5,9- and 1,5,7-Triols via Configuration-Encoded 1,5-Polyol Synthesis: Enantioselective Preparation of γ-Sulfonyl-α-silyloxyaldehydes and Iterative Julia-Kocienski Coupling. J Org Chem 2018; 83:13636-13649. [PMID: 30365891 DOI: 10.1021/acs.joc.8b02033] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Diverse classes of natural products contain chiral 1,5-polyols, within which may be stereochemical triads of 1,5,9- and 1,5,7-triols. Biological activities associated with compounds containing these motifs warrant targeted synthetic strategies to access all stereoisomers of a 1,5-polyol family from cheap and easily accessible reagents while avoiding the need to determine configurations at each alcohol stereocenter. Here, we address these problems via design and implementation of an iterative configuration-encoded strategy to access 1,5-polyols with unambiguous stereocontrol; the coupling event exploits Julia-Kocienski reactions of enantiopure α-silyloxy-γ-sulfononitriles. These building blocks, bearing sulfone at one terminus and α-silyloxyaldehyde (in latent form) at the other, were prepared via asymmetric catalysis. An efficient scalable route to these building blocks was developed, leading to enantiopure samples in multigram quantities. Preliminary studies of acetals as the latent aldehyde functionality in the α-silyloxyaldehyde showed that Julia-Kocienski coupling of these building blocks was effective, but iterative application was thwarted during acetal hydrolysis, leading to use of nitrile to perform the latent aldehyde function. A variety of 1,5-polyols, including a 1,5,9,13-tetraol and a differentially protected 1,5,9-triol, were prepared, validating the approach. The accompanying paper describes the application of this configuration-encoded 1,5-polyol synthesis to 1,5,9- and 1,5,7-triols found in tetrafibricin.
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Affiliation(s)
- Ryan M Friedrich
- Department of Chemistry , University of Iowa , Iowa City , Iowa 52242 , United States
| | | | - Jacob Hackbarth
- Department of Chemistry , University of Iowa , Iowa City , Iowa 52242 , United States
| | - Gregory K Friestad
- Department of Chemistry , University of Iowa , Iowa City , Iowa 52242 , United States
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7
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Friedrich RM, Friestad GK. Access to ananti,syn-1,5,7-Triol by Configuration-Encoded 1,5-Polyol Synthesis: The C15-C25 Fragment of Tetrafibricin. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700373] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Ryan M. Friedrich
- Department of Chemistry; University of Iowa; 52242 Iowa City Iowa USA
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8
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Itoh T, Montgomery TP, Recio A, Krische MJ. Asymmetric alcohol C-H allylation and syn-crotylation: C9-C20 of tetrafibricin. Org Lett 2014; 16:820-3. [PMID: 24422777 PMCID: PMC3932543 DOI: 10.1021/ol403566w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The C9-C20 segment of the fibrinogen receptor inhibitor tetrafibricin was prepared in 10 steps (longest linear sequence). Ruthenium catalyzed enantioselective syn-crotylation is used to construct C9-C13. Iridium catalyzed asymmetric alcohol C-H allylation of a commercial malic acid derived alcohol is used to construct C14-C20. Recovery and recycling of the iridium catalyst is described.
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Affiliation(s)
- Takahiko Itoh
- University of Texas at Austin, Department of Chemistry and Biochemistry, Austin, TX 78712
| | - T. Patrick Montgomery
- University of Texas at Austin, Department of Chemistry and Biochemistry, Austin, TX 78712
| | - Antonio Recio
- University of Texas at Austin, Department of Chemistry and Biochemistry, Austin, TX 78712
| | - Michael J. Krische
- University of Texas at Austin, Department of Chemistry and Biochemistry, Austin, TX 78712
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9
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Nuhant P, Roush WR. Enantio- and diastereoselective synthesis of N-acetyl dihydrotetrafibricin methyl ester. J Am Chem Soc 2013; 135:5340-3. [PMID: 23530855 PMCID: PMC3679187 DOI: 10.1021/ja401918r] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A highly diastereoselective synthesis of N-acetyl dihydrotetrafibricin methyl ester (34) is described. The synthesis features three enantioselective double allylboration reactions and an intramolecular hydrosilylation/Fleming-Tamao oxidation sequence to establish seven of the hydroxy-bearing stereocenters of 34. Especially noteworthy is the fragment-assembly double allyboration reaction of 2 and 7 using reagent 3, which provides the advanced intermediate 6 with >20:1 diastereoselectivity.
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Affiliation(s)
- Philippe Nuhant
- Department of Chemistry, Scripps Florida, Jupiter, Florida 33458
| | - William R. Roush
- Department of Chemistry, Scripps Florida, Jupiter, Florida 33458
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11
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Nuhant P, Kister J, Lira R, Sorg A, Roush WR. Development of a Double Allylboration Reagent Targeting 1,5-syn-(E)-Diols: Application to the Synthesis of the C(23)-C(40) Fragment of Tetrafibricin. Tetrahedron 2011; 67:6497-6512. [PMID: 21857752 PMCID: PMC3156408 DOI: 10.1016/j.tet.2011.06.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Interest in the synthesis of the C(23)-C(40) fragment 2 of tetrafibricin prompted us to develop a new method for the synthesis of 1,5-syn-(E)-diols. Toward this end, the kinetically controlled hydroboration of allenes 6, 33, ent-39, 42 and 45 with the Soderquist borane 25R were studied. Tetrabutylammonium allenyltrifluoroborate 45 gave superior results and was utilized in a double allylboration sequence with two different aldehydes to provide the targeted 1,5-syn-(E)-diols in generally high yields (72-98%), and with high enantioselectivity (>95% e.e.), diastereoselectivity (d.r. >20:1), and (E)/(Z) selectivity (>20:1). This new method was applied to the synthesis of the C(23)-C(40) fragment 2 of tetrafibricin.
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Affiliation(s)
| | | | | | | | - William R. Roush
- Departments of Chemistry, The Scripps Research Institute, Florida, 130 Scripps Way, Jupiter, FL 33458, USA
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12
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Kumpulainen ETT, Kang B, Krische MJ. C(21)-C(40) of tetrafibricin via metal catalysis: beyond stoichiometric chiral reagents, auxiliaries, and premetalated nucleophiles. Org Lett 2011; 13:2484-7. [PMID: 21469726 PMCID: PMC3084888 DOI: 10.1021/ol200735r] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The C(21)-C(40) fragment of fibrinogen receptor inhibitor tetrafibricin was prepared in 12 steps from propane diol (longest linear sequence). In this approach, 6 C-C bonds are formed via asymmetric iridium catalyzed transfer hydrogenative carbonyl allylation and 2 C═C bonds are formed via Grubbs olefin cross-metathesis.
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Affiliation(s)
- Esa T. T. Kumpulainen
- University of Texas at Austin, Department of Chemistry and Biochemistry, Austin, TX 78712
| | - Byungsoo Kang
- University of Texas at Austin, Department of Chemistry and Biochemistry, Austin, TX 78712
| | - Michael J. Krische
- University of Texas at Austin, Department of Chemistry and Biochemistry, Austin, TX 78712
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13
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Kister J, Nuhant P, Lira R, Sorg A, Roush WR. Enantio- and diastereoselective synthesis of (E)-1,5-syn-diols: application to the synthesis of the C(23)-C(40) fragment of tetrafibricin. Org Lett 2011; 13:1868-71. [PMID: 21375316 PMCID: PMC3064748 DOI: 10.1021/ol2003836] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A highly stereoselective synthesis of (E)-1,5-syn-diols 6 is described. The kinetically controlled hydroboration of allenyltrifluoroborate 8 with Soderquist borane 2 provides the (Z)-allylic trifluoroborate 9, which undergoes sequential allylboration with two different aldehydes to provide (E)-1,5-syn-diols 6 in 72-98% yields with >95% ee and >20:1 dr. Application of this method to the synthesis of the tetrafibricin C(23)-C(40) fragment 19 is described.
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Affiliation(s)
- Jeremy Kister
- Department of Chemistry, Scripps Florida, Jupiter, FL 33458
| | | | - Ricardo Lira
- Department of Chemistry, Scripps Florida, Jupiter, FL 33458
| | - Achim Sorg
- Department of Chemistry, Scripps Florida, Jupiter, FL 33458
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