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Chaudhary NK, Taylor WC, Mander LN, Karuso P. Isolation and Structure Elucidation of Additional Alkaloids from the Tropical Rainforest Tree Galbulimima baccata. JOURNAL OF NATURAL PRODUCTS 2021; 84:2525-2535. [PMID: 34491059 DOI: 10.1021/acs.jnatprod.1c00537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The structures of five new natural products (GB 27-GB 31, 1-5), isolated as minor components from the bark of Galbulimima baccata, have been determined by 2D NMR spectroscopy in combination with DFT calculations. Among the alkaloids, GB 31 (5) belongs to Class I, GB 27 (1) and 28 (2) belong to Class II, and GB 30 (4) belongs to Class III GB alkaloids. GB 31 is the first non-nitrogen-containing GB "alkaloid", being a biosynthetic oxidation product of himbacine, himandravine, or himbeline. GB 29 (3) has an entirely new natural product scaffold but belongs to Class IV (miscellaneous alkaloids). The isolation of a new Galbulimima scaffold has revealed a new pathway in the biosynthesis of the GB alkaloids. The new molecules isolated have shed further light on the biogenetic relationship among these structurally unique and complex groups of alkaloids. We present, for the first time, a unified biogenesis for the GB alkaloids that were first isolated in the 1950s and now number over 40 examples. This work also brings full circle the story of Galbulimima alkaloids. A life-long project of Wal Taylor involving one of his first students (Lew Mander) and one of his last students (Peter Karuso), a story stretching over six decades, has come to a final conclusion.
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Affiliation(s)
- Nirmal K Chaudhary
- Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Walter C Taylor
- School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia
| | - Lewis N Mander
- Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia
| | - Peter Karuso
- Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
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Williams CM, Dallaston MA. The Future of Retrosynthesis and Synthetic Planning: Algorithmic, Humanistic or the Interplay? Aust J Chem 2021. [DOI: 10.1071/ch20371] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The practice of deploying and teaching retrosynthesis is on the cusp of considerable change, which in turn forces practitioners and educators to contemplate whether this impending change will advance or erode the efficiency and elegance of organic synthesis in the future. A short treatise is presented herein that covers the concept of retrosynthesis, along with exemplified methods and theories, and an attempt to comprehend the impact of artificial intelligence in an era when freely and commercially available retrosynthetic and forward synthesis planning programs are increasingly prevalent. Will the computer ever compete with human retrosynthetic design and the art of organic synthesis?
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Lan P, Herlt AJ, Willis AC, Taylor WC, Mander LN. Structures of New Alkaloids from Rain Forest Trees Galbulimima belgraveana and Galbulimima baccata in Papua New Guinea, Indonesia, and Northern Australia. ACS OMEGA 2018; 3:1912-1921. [PMID: 31458503 PMCID: PMC6641496 DOI: 10.1021/acsomega.7b02065] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 01/31/2018] [Indexed: 06/10/2023]
Abstract
Following on our 60-year research on the chemical constituents of the rain forest trees Galbulimima belgraveana and Galbulimima baccata, we report the isolation of seven new alkaloids: GB14 (14), GB22 (15), GB25 (16), GB21 (17), GB23 (18), GB24 (19), and GB26 (20). Their structures were elucidated by a combination of spectroscopic analyses and single-crystal X-ray crystallography, as well as structure degradation and interconversion. The newly isolated alkaloids are precursors or derivatives of the known family members from our early studies and could be intermediates in the biosynthesis of the Galbulimima alkaloids. Therefore, the present study has expanded the range of structures in this family of alkaloids and provided some missing links in the biosynthetic sequences.
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Affiliation(s)
- Ping Lan
- Department
of Food Science and Engineering, Jinan University, Guangzhou 510632, China
| | - Anthony J. Herlt
- Research
School of Chemistry, Australian National
University, Canberra, Australian Capital Territory 2601, Australia
| | - Anthony C. Willis
- Research
School of Chemistry, Australian National
University, Canberra, Australian Capital Territory 2601, Australia
| | - Walter C. Taylor
- School
of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Lewis N. Mander
- Research
School of Chemistry, Australian National
University, Canberra, Australian Capital Territory 2601, Australia
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Abstract
This chapter provides a comprehensive overview of recent achievements in the area of Galbulimima alkaloids. Following a discussion of the isolation of Galbulimima alkaloids and structural features of members of this fascinating family of secondary metabolites, biological properties of selected compounds are briefly discussed. Furthermore, the proposed biosynthetic routes toward Galbulimima alkaloids are outlined. The main section of the chapter is devoted to a detailed discussion and comparison of all total syntheses of Galbulimima alkaloids published to date.
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Affiliation(s)
- Uwe Rinner
- Sultan Qaboos University, Al-Khoud, Sultanate of Oman.
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Kasahara T, Ciufolini MA. Further studies toward himandrine via sequential oxidative amidation – intramolecular Diels–Alder reactions. CAN J CHEM 2013. [DOI: 10.1139/cjc-2012-0340] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Exploratory work toward the alkaloid himandrine evaluated the directing ability of a pyrrolidine C-3 substituent in a diastereotopic group elective intramolecular Diels–Alder reaction of a spirodienone obtained by the oxidative amidation of a phenol. The study also defined a technique for the construction of ring D of the alkaloid.
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Affiliation(s)
- Takahito Kasahara
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Marco A. Ciufolini
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
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Evans DA, Adams DJ, Kwan EE. Progress toward the Syntheses of (+)-GB 13, (+)-Himgaline, and Himandridine. New Insights into Intramolecular Imine/Enamine Aldol Cyclizations. J Am Chem Soc 2012; 134:8162-70. [DOI: 10.1021/ja3001776] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- David A. Evans
- Department of Chemistry & Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Drew J. Adams
- Department of Chemistry & Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Eugene E. Kwan
- Department of Chemistry & Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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Liang H, Ciufolini MA. Tandem phenolic oxidative amidation-intramolecular Diels-Alder reaction: an approach to the himandrine core. Org Lett 2010; 12:1760-3. [PMID: 20329732 DOI: 10.1021/ol1003669] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An oxidative cyclization of dienic sulfonamides mediated by iodobenzene diacetate in TFA, followed by a tandem intramolecular Diels-Alder reaction, achieves desymmetrization of a "locally symmetrical" dienone with good levels of diastereoselectivity and leads to valuable synthetic intermediates for the himandrine alkaloids.
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Affiliation(s)
- Huan Liang
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
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O'Connor PD, Del Signore G, McLachlan MMW, Willis AC, Mander LN. Approaches to the Synthesis of the Galbulimima Alkaloid Himandrine. Aust J Chem 2010. [DOI: 10.1071/ch10252] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The hexacyclic skeleton of himandrine (2), which is present in 15 of the more complex alkaloids obtained from the bark of the tropical rain forest tree Galbulimima belgraveana has been prepared by means of a 19-step synthesis beginning with the known [3.2.1]-benzobicyclooctene intermediate 9. An alternative approach is also described, thus far culminating in 34. Key transformations include Diels–Alder cycloadditions, ring contractions, a Curtius rearrangement, a Birch reduction, an intramolecular nucleophilic amination, and a palladium-mediated alkene amination.
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Mander LN, Willis AC, Herlt AJ, Taylor WC. The structures of three new Galbulimima alkaloids. Tetrahedron Lett 2009. [DOI: 10.1016/j.tetlet.2009.10.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abstract
We describe the first total synthesis of (-)-himandrine, a member of the class II galbulimima alkaloids. Noteworthy features of this chemistry include a diastereoselective Diels-Alder reaction in the rapid synthesis of the tricycle ABC-ring system in an enantiomerically enriched form, the use of a formal [3+3] annulation strategy to secure the CDE-ring system with complete diastereoselection, and successful implementation of our biogenetically inspired oxidative spirocyclization of an advanced intermediate. The successful and direct late-stage formation of the F-ring in the hexacyclic core of himandrine drew on the power of biogenetic considerations and fully utilized the inherent chemistry of a plausible biosynthetic intermediate.
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Affiliation(s)
- Mohammad Movassaghi
- Massachusetts Institute of Technology, Department of Chemistry, Cambridge, Massachusetts 02139, USA.
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Shah U, Chackalamannil S, Ganguly AK, Chelliah M, Kolotuchin S, Buevich A, McPhail A. Total synthesis of (-)-himgaline. J Am Chem Soc 2007; 128:12654-5. [PMID: 17002352 DOI: 10.1021/ja065198n] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The first total synthesis of (-)-himgaline and a highly enantioselective synthesis of its congener (-)-GB 13 are described. Decarboxylative aza-Michael reaction of the hexacyclic lactone precursor under acidic conditions, followed by basic workup, yielded (-)-GB 13 in 80% yield. Cyclization of (-)-GB 13 to oxohimgaline under acidic conditions, followed by internally coordinated sodium triacetoxyborohydride reduction, gave (-)-himgaline as the exclusive product.
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Affiliation(s)
- Unmesh Shah
- Schering-Plough Research Institute, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
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