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Frontier AJ, Sinclair PP. Merging Strategy, Improvisation, and Conversation to Solve Problems in Target Synthesis. Acc Chem Res 2021; 54:1817-1829. [PMID: 33705115 DOI: 10.1021/acs.accounts.0c00804] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Total synthesis has long been depicted as the quest to conquer the structures created by nature, requiring an unflinching, single-minded devotion to the task. The goal is achieved by chemists with grit, strength of will, and a competitive spirit. While there is some truth to this viewpoint, it does not fully capture the rich experiences gained in this research realm. In our lab, strategic planning, improvisation, and conversation have worked in concert to enable progress. This Account summarizes our efforts to synthesize four different bioactive targets: merrilactone A, rocaglamide, phomactin A, and tetrapetalone A. Certain missteps were integral to success in these synthetic projects. As such, we include the hiccups, and their roles in the evolution of the strategies, along with the results that aligned with our expectations.Two of these projects (merrilactone A and rocaglamide) culminated in the total synthesis of the targets. The challenges presented by merrilactone A spawned a new design strategy for pentannulation using Nazarov cyclization chemistry. This work demonstrated that Lewis acid catalysis is often a viable electrocyclization strategy in activated, polarized pentadienyl cation intermediates. We sought to apply the same logic to the rocaglamide target, but precursors we prepared did not behave according to plan. This situation pushed us to adapt our approach to match the innate reactivity of the substrate, resulting in an on-the-spot improvisation that was not only integral to the success of the project but also expanded our understanding of pentadienyl cation chemistry. In the other two projects (phomactin A and tetrapetalone A), we did not complete a total synthesis but did build the polycyclic core of the target. Even though the hetero [4 + 2] cycloaddition plan for assembling the macrocyclic oxadecalin ring system of phomactin A failed, the original experimental design still enabled us to solve the problem. Through a wholly unanticipated series of events, our focus on the oxadecalin ring system primed us for the discovery of a sequential iodoaldol/oxa-Michael sequence, using the original [4 + 2] building blocks. Then, the bridging ring present in phomactin A demanded we implement this sequence in a transannular fashion. Finally, our successful synthesis of the tetrapetalone core was enabled by consultations with others in the community. Each bond formation seemed to require different expertise, and in three separate instances (C-N cross-coupling, diastereoselective ring-closing metathesis, and oxidative dearomatization) synthetic challenges were overcome through conversation and collaboration.In our experience, the amount of creative power we summon during a target synthesis project correlates directly with the magnitude of the structural challenges we face. When reactivity surprises us, we analyze the problem anew, consult with colleagues, and improvise with the tools at hand. The inevitable misbehavior of a complex system is a strong motivating force, and one that has helped to shape our research program for nearly two decades.
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Affiliation(s)
- Alison J. Frontier
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester New York 14611, United States
| | - Paul P. Sinclair
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester New York 14611, United States
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Leger PR, Kuroda Y, Chang S, Jurczyk J, Sarpong R. C-C Bond Cleavage Approach to Complex Terpenoids: Development of a Unified Total Synthesis of the Phomactins. J Am Chem Soc 2020; 142:15536-15547. [PMID: 32799452 PMCID: PMC7771649 DOI: 10.1021/jacs.0c07316] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The rearrangement of carbon-carbon (C-C) single bonds in readily available carbocyclic scaffolds can yield uniquely substituted carbocycles that would be challenging to construct otherwise. This is a powerful and often non-intuitive approach for complex molecule synthesis. The transition-metal-mediated cleavage of C-C bonds has the potential to broaden the scope of this type of skeletal remodeling by providing orthogonal selectivities compared to more traditional pericyclic and carbocation-based rearrangements. To highlight this emerging technology, a unified, asymmetric, total synthesis of the phomactin terpenoids was developed, enabled by the selective C-C bond cleavage of hydroxylated pinene derivatives obtained from carvone. In this full account, the challenges, solutions, and intricacies of Rh(I)-catalyzed cyclobutanol C-C cleavage in a complex molecule setting are described. In addition, details of the evolution of strategies that ultimately led to the total synthesis of phomactins A, K, P, R, and T, as well as the synthesis and structural reassignment of Sch 49027, are given.
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Affiliation(s)
- Paul R Leger
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Yusuke Kuroda
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Stanley Chang
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Justin Jurczyk
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Richmond Sarpong
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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Affiliation(s)
- Carmen Nájera
- Centro de Innovación en Química Avanzada (ORFEO−CINQA), Universidad de Alicante, Apdo. 99, Alicante E-03080, Spain
| | - Leiv K. Sydnes
- Department of Chemistry, University of Bergen, Allégt. 41, Bergen NO-5007, Norway
| | - Miguel Yus
- Centro de Innovación en Química Avanzada (ORFEO−CINQA), Universidad de Alicante, Apdo. 99, Alicante E-03080, Spain
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Blackburn TJ, Thomas EJ. Synthetic approaches to phomactins: Novel oxidation of homoallylic alcohols using tetra-n-propylammonium perruthenate. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.05.068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Min BK, Seo DY, Ryu JY, Lee J, Kim JN. Synthesis of Spirocyclohexadieneyl-2-Oxindoles by 6π-Electrocyclization of Trienes Derived from Wittig Reaction of Morita-Baylis-Hillman Carbonates and α,β-Unsaturated Aldehydes. B KOREAN CHEM SOC 2017. [DOI: 10.1002/bkcs.11333] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Beom Kyu Min
- Department of Chemistry and Institute of Basic Science; Chonnam National University; Gwangju 500-757 Korea
| | - Da Young Seo
- Department of Chemistry and Institute of Basic Science; Chonnam National University; Gwangju 500-757 Korea
| | - Ji Yeon Ryu
- Department of Chemistry and Institute of Basic Science; Chonnam National University; Gwangju 500-757 Korea
| | - Junseong Lee
- Department of Chemistry and Institute of Basic Science; Chonnam National University; Gwangju 500-757 Korea
| | - Jae Nyoung Kim
- Department of Chemistry and Institute of Basic Science; Chonnam National University; Gwangju 500-757 Korea
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Blackburn TJ, Kilner MJ, Thomas EJ. Synthetic approaches to phomactins: on the stereoselectivity of some [2,3]-Wittig rearrangements. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Isobe M, Chang WC, Tsou PK, Ploysuk C, Yu CH. Stereochemical Course of Wittig Rearrangements of Dihydropyran Allyl Propargyl Ethers. J Org Chem 2015; 80:6222-37. [DOI: 10.1021/acs.joc.5b00678] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Minoru Isobe
- Department
of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan
| | - Wei-Chung Chang
- Department
of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan
| | - Pei-Kang Tsou
- Department
of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan
| | - Chatchawan Ploysuk
- Department
of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan
| | - Chin-Hui Yu
- Department
of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan
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Du G, Bao W, Huang J, Huang S, Yue H, Yang W, Zhu L, Liang Z, Lee CS. Enantioselective Synthesis of the ABC-Tricyclic Core of Phomactin A by a γ-Hydroxylation Strategy. Org Lett 2015; 17:2062-5. [DOI: 10.1021/acs.orglett.5b00586] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Guangyan Du
- Laboratory of Chemical Genomics,
School of Chemical Biology and Biotechnology, Peking University Shenzhen
Graduate School, Shenzhen University Town, Xili, Shenzhen 518055, China
| | - Wenli Bao
- Laboratory of Chemical Genomics,
School of Chemical Biology and Biotechnology, Peking University Shenzhen
Graduate School, Shenzhen University Town, Xili, Shenzhen 518055, China
| | - Junrong Huang
- Laboratory of Chemical Genomics,
School of Chemical Biology and Biotechnology, Peking University Shenzhen
Graduate School, Shenzhen University Town, Xili, Shenzhen 518055, China
| | - Shuangping Huang
- Laboratory of Chemical Genomics,
School of Chemical Biology and Biotechnology, Peking University Shenzhen
Graduate School, Shenzhen University Town, Xili, Shenzhen 518055, China
| | - Hong Yue
- Laboratory of Chemical Genomics,
School of Chemical Biology and Biotechnology, Peking University Shenzhen
Graduate School, Shenzhen University Town, Xili, Shenzhen 518055, China
| | - Wei Yang
- Laboratory of Chemical Genomics,
School of Chemical Biology and Biotechnology, Peking University Shenzhen
Graduate School, Shenzhen University Town, Xili, Shenzhen 518055, China
| | - Lizhi Zhu
- Laboratory of Chemical Genomics,
School of Chemical Biology and Biotechnology, Peking University Shenzhen
Graduate School, Shenzhen University Town, Xili, Shenzhen 518055, China
| | - Zhenhao Liang
- Laboratory of Chemical Genomics,
School of Chemical Biology and Biotechnology, Peking University Shenzhen
Graduate School, Shenzhen University Town, Xili, Shenzhen 518055, China
| | - Chi-Sing Lee
- Laboratory of Chemical Genomics,
School of Chemical Biology and Biotechnology, Peking University Shenzhen
Graduate School, Shenzhen University Town, Xili, Shenzhen 518055, China
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Wang CY, Dong C, Zheng ZJ, Xu Z, Yang KF, Xu LW. Construction of an all-substituted pyrrolidine derivative with multiple stereogenic centers and Betti-base-derived γ-amino alcohols by [1,2]-Wittig rearrangement. RSC Adv 2015. [DOI: 10.1039/c5ra09145d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The construction of Betti base-derived γ-amino alcohols and all-substituted pyrrolidine derivative with multiple stereogenic centers has been developed successfully through neighboring lithium-assisted [1,2]-Wittig rearrangement (NLAWR).
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Affiliation(s)
- Cai-Yun Wang
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
| | - Cheng Dong
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
| | - Zhan-Jiang Zheng
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
| | - Zheng Xu
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
| | - Ke-Fang Yang
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
| | - Li-Wen Xu
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
- State Key Laboratory for Oxo Synthesis and Selective Oxidation
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Ciesielski J, Frontier A. The Phomactin Natural Products from Isolation to Total Synthesis: A Review. ORG PREP PROCED INT 2014. [DOI: 10.1080/00304948.2014.903142] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Ciesielski J, Gandon V, Frontier AJ. Cascade cyclizations of acyclic and macrocyclic alkynones: studies toward the synthesis of phomactin A. J Org Chem 2013; 78:9541-52. [PMID: 23724905 DOI: 10.1021/jo4007514] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A study of the reactivity and diastereoselectivity of the Lewis acid promoted cascade cyclizations of both acyclic and macrocyclic alkynones is described. In these reactions, a β-iodoallenolate intermediate is generated via conjugate addition of iodide to an alkynone followed by an intramolecular aldol reaction with a tethered aldehyde to afford a cyclohexenyl alcohol. The Lewis acid magnesium iodide (MgI2) was found to promote irreversible ring closure, while cyclizations using BF3·OEt2 as promoter occurred reversibly. For both acyclic and macrocyclic alkynones, high diastereoselectivity was observed in the intramolecular aldol reaction. The MgI2 protocol for cyclization was applied to the synthesis of advanced intermediates relevant to the synthesis of phomactin natural products, during which a novel transannular cation-olefin cyclization was observed. DFT calculations were conducted to analyze the mechanism of this unusual MgI2-promoted process.
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Affiliation(s)
- Jennifer Ciesielski
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
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Ciesielski J, Lebœuf D, Stern HA, Frontier AJ. Gold (III) Chloride-Catalyzed 6- endo- trig Oxa-Michael Addition Reactions for Diastereoselective Synthesis of Fused Tetrahydropyranones. Adv Synth Catal 2013; 355:2077-2082. [PMID: 24032002 PMCID: PMC3767299 DOI: 10.1002/adsc.201300265] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Alkynones were treated with boron trifluoride diethyl etherate to generate β-iodoallenolates, which underwent intramolecular aldol reactions to produce cycloalkenyl alcohols. Diastereoselective oxa-Michael ring closure could then be induced by treatment with a catalytic amount of gold(III) chloride, affording highly functionalized tetrahydropyran-containing ring systems.
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Fretz SJ, Hadad CM, Hart DJ, Vyas S, Yang D. Birch Reductive Alkylation of Methyl m-(Hydroxymethyl)benzoate Derivatives and the Behavior of o- and p-(Hydroxymethyl)benzoates under Reductive Alkylation Conditions. J Org Chem 2012; 78:83-92. [PMID: 23106774 DOI: 10.1021/jo301872n] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Samuel J. Fretz
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus,
Ohio 43210, United States
| | - Christopher M. Hadad
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus,
Ohio 43210, United States
| | - David J. Hart
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus,
Ohio 43210, United States
| | - Shubham Vyas
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus,
Ohio 43210, United States
| | - Dexi Yang
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus,
Ohio 43210, United States
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Ciesielski J, Cariou K, Frontier AJ. A macrocyclic β-iodoallenolate intermediate is key: synthesis of the ABD core of phomactin A. Org Lett 2012; 14:4082-5. [PMID: 22853449 PMCID: PMC3448491 DOI: 10.1021/ol3017116] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An enantioselective strategy for the synthesis of phomactin natural products is described. The Lewis acid triggered cyclization of a β-iodoallenolate embedded in a 12-membered macrocycle was used to obtain a highly functionalized bicyclo[9.3.1]pentadecane in good yield and high diastereoselectivity. This iodoenone contains the substituents of the AD ring system of the phomactin family of natural products, appropriate for further functionalization. Synthesis of the oxadecalin core of phomactin A from the AD iodoenone intermediate was achieved. In this unusual strategy, rings A and B are both fashioned within a macrocyclic precursor.
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Affiliation(s)
- Jennifer Ciesielski
- Department of Chemistry, University of Rochester, Rochester, New York, 14627
| | - Kevin Cariou
- Department of Chemistry, University of Rochester, Rochester, New York, 14627
| | - Alison J. Frontier
- Department of Chemistry, University of Rochester, Rochester, New York, 14627
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Sun X, Lei J, Sun C, Song Z, Yan L. [1,5]-Anion Relay/[2,3]-Wittig Rearrangement of 3,3-Bis(silyl) Allyl Enol Ethers: Synthesis of Useful Vinyl Bis(silane) Species. Org Lett 2012; 14:1094-7. [PMID: 22276938 DOI: 10.1021/ol300004b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Xianwei Sun
- Key Laboratory of Drug-Targeting of Education Ministry and Department of Medicinal Chemistry, West China School of Pharmacy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, P. R. China
| | - Jian Lei
- Key Laboratory of Drug-Targeting of Education Ministry and Department of Medicinal Chemistry, West China School of Pharmacy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, P. R. China
| | - Changzhen Sun
- Key Laboratory of Drug-Targeting of Education Ministry and Department of Medicinal Chemistry, West China School of Pharmacy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, P. R. China
| | - Zhenlei Song
- Key Laboratory of Drug-Targeting of Education Ministry and Department of Medicinal Chemistry, West China School of Pharmacy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, P. R. China
| | - Linjie Yan
- Key Laboratory of Drug-Targeting of Education Ministry and Department of Medicinal Chemistry, West China School of Pharmacy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, P. R. China
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Buchanan GS, Cole KP, Li G, Tang Y, You LF, Hsung RP. Constructing the Architecturally Distinctive ABD-Tricycle of Phomactin A through an Intramolecular Oxa-[3 + 3] Annulation Strategy. Tetrahedron 2011; 67:10105-10118. [PMID: 23750054 PMCID: PMC3676308 DOI: 10.1016/j.tet.2011.09.111] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Our efforts in constructing the ABD-ring of phomactin A through an intramolecular oxa-[3 + 3] annulation strategy is described. This struggle entailed finding a practical and efficient preparation of annulation precursor, and a realization of the unexpected competing regioisomeric pathway. The success entailed accessing the A-ring through Diels-Alder cycloaddition of Rawal's diene. Furthermore, the discovery that the regioisomers from the annulation existed as atropisomers with respect to the D-ring olefin and that they could be equilibrated to the desired ABD-tricycle, allowing large quantities of tricycle to be accessed.
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Affiliation(s)
- Grant S Buchanan
- Division of Pharmaceutical Sciences and Department of Chemistry, University of Wisconsin, Madison, WI 53705 USA
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Buchanan GS, Cole KP, Tang Y, Hsung RP. Total synthesis of (±)-phomactin A. Lessons learned from respecting a challenging structural topology. J Org Chem 2011; 76:7027-39. [PMID: 21819039 PMCID: PMC3163054 DOI: 10.1021/jo200936r] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Our struggles and ultimate success in achieving a total synthesis of phomactin A are described. Our strategy features an intramolecular oxa-[3 + 3] annulation to construct its unique ABD-tricyclic manifold. Although the synthesis would constitute a distinctly new approach with the 12-membered D-ring of phomactin A being assembled simultaneously with the 1-oxadecalin at an early stage, the ABD-tricycle represents a unique structural topology that would pose a number of unprecedented challenges. One challenge concerned elaborating this tricycle to have oxygenation at the proper carbon atoms. To overcome this, we would utilize a Kornblum-DeLaMare ring-opening of a peroxide bridge as well as a challenging late-stage 1,3-allylic alcohol transposition. Further, the structural intricacies of the ABD-tricycle were uncovered by a conformational analysis that would be critical for the C5a-homologation.
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Affiliation(s)
- Grant S. Buchanan
- Division of Pharmaceutical Sciences and Department of Chemistry University of Wisconsin, Madison, WI 53705
| | - Kevin P. Cole
- Chemical Product R&D, Eli Lilly and Company, Indianapolis, IN 46284
| | - Yu Tang
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072 P. R. China
| | - Richard P. Hsung
- Division of Pharmaceutical Sciences and Department of Chemistry University of Wisconsin, Madison, WI 53705
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Kim SH, Lee HS, Park BR, Kim JN. Base-Mediated Aerobic Oxidation of Hagemann's Ester: Competitive Hydroxylation at C-1 and C-3 Positions. B KOREAN CHEM SOC 2011. [DOI: 10.5012/bkcs.2011.32.5.1725] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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McGowan G, Thomas EJ. Synthesis of macrocyclic precursors of phomactins using [2,3]-Wittig rearrangements. Org Biomol Chem 2009; 7:2576-90. [DOI: 10.1039/b903256h] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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