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Begum S, Bhattacharya R, Paul S, Chakraborty TK. Cp 2TiCl-Promoted Endo-Trig Radical Cyclization to Six- and Seven-Membered Carbocycles: Synthesis of (±)-Isoclavukerin A. J Org Chem 2023; 88:12677-12697. [PMID: 37608565 DOI: 10.1021/acs.joc.3c01356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
A systematic study is undertaken to investigate the less explored endo-trig radical cyclization in activated olefin-appended epoxides using Cp2TiCl. The radical generated by the Ti(III)-promoted reductive opening of the epoxy ring promptly underwent endo-trig cyclization, giving access to differently 1,3-disubstituted six- and seven-membered carbocycles in good yields and diastereoselectivity. This protocol was successfully employed in the construction of 5,7- and 6,7-fused bicyclic frameworks entailing a de novo synthesis of (±)-isoclavukerin A belonging to tri-nor-guaiane class of sesquiterpene natural products in eight simple steps from commercially available starting materials. Besides the Ti(III)-mediated reaction serving as a key step in the synthesis, a sequential [2,3]-sigmatropic rearrangement/syn-elimination of an allyl sulfenate intermediate successfully rendered the highly constrained diene moiety in the hydroazulene core of the target molecule.
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Affiliation(s)
- Sabnam Begum
- Department of Organic Chemistry, Indian Institute of Science, Bengaluru 560012, India
| | - Rajarshi Bhattacharya
- Department of Organic Chemistry, Indian Institute of Science, Bengaluru 560012, India
| | - Shashwati Paul
- Department of Organic Chemistry, Indian Institute of Science, Bengaluru 560012, India
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2
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Bartolo ND, Read JA, Valentín EM, Woerpel KA. Reactions of Allylmagnesium Reagents with Carbonyl Compounds and Compounds with C═N Double Bonds: Their Diastereoselectivities Generally Cannot Be Analyzed Using the Felkin-Anh and Chelation-Control Models. Chem Rev 2020; 120:1513-1619. [PMID: 31904936 PMCID: PMC7018623 DOI: 10.1021/acs.chemrev.9b00414] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
This review describes the additions of allylmagnesium reagents to carbonyl compounds and to imines, focusing on the differences in reactivity between allylmagnesium halides and other Grignard reagents. In many cases, allylmagnesium reagents either react with low stereoselectivity when other Grignard reagents react with high selectivity, or allylmagnesium reagents react with the opposite stereoselectivity. This review collects hundreds of examples, discusses the origins of stereoselectivities or the lack of stereoselectivity, and evaluates why selectivity may not occur and when it will likely occur.
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Affiliation(s)
- Nicole D. Bartolo
- Department of Chemistry, New York University, 100
Washington Square East, New York, NY 10003, USA
| | - Jacquelyne A. Read
- Department of Chemistry, New York University, 100
Washington Square East, New York, NY 10003, USA
- Department of Chemistry, University of Utah, 315 South 1400
East, Salt Lake City, UT 84112, USA
| | - Elizabeth M. Valentín
- Department of Chemistry, New York University, 100
Washington Square East, New York, NY 10003, USA
- Department of Chemistry, Susquehanna University, 514
University Avenue, Selinsgrove, PA 17870, USA
| | - K. A. Woerpel
- Department of Chemistry, New York University, 100
Washington Square East, New York, NY 10003, USA
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Robertson J, Stevens K. Pyrrolizidine alkaloids: occurrence, biology, and chemical synthesis. Nat Prod Rep 2017; 34:62-89. [PMID: 27782262 DOI: 10.1039/c5np00076a] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Covering: 2013 up to the end of 2015This review covers the isolation and structure of new pyrrolizidines; pyrrolizidine biosynthesis; biological activity, including the occurrence of pyrrolizidines as toxic components or contaminants in foods and beverages; and formal and total syntheses of naturally-occurring pyrrolizidine alkaloids and closely related non-natural analogues.
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Affiliation(s)
- Jeremy Robertson
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
| | - Kiri Stevens
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
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Ran GY, Gong M, Yue JF, Yang XX, Zhou SL, Du W, Chen YC. Asymmetric Cascade Assembly of 1,2-Diaza-1,3-dienes and α,β-Unsaturated Aldehydes via Dienamine Activation. Org Lett 2017; 19:1874-1877. [PMID: 28350461 DOI: 10.1021/acs.orglett.7b00636] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Guang-Yao Ran
- Department
of Medicinal Chemistry, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Ming Gong
- Ruian City People’s Hospital, Ruian 325200, Zhejiang
Province, China
| | - Jing-Fei Yue
- Department
of Medicinal Chemistry, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Xing-Xing Yang
- Department
of Medicinal Chemistry, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Su-Lan Zhou
- Department
of Medicinal Chemistry, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Wei Du
- Department
of Medicinal Chemistry, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Ying-Chun Chen
- Department
of Medicinal Chemistry, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
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Das P, Ajay S, Shaw AK. Palladium(II)-catalyzed intramolecular aminoacetoxylation of sugar derived alkenyl tosylsulfonamide: Total synthesis of l-deoxyallonojirimycin. Tetrahedron Lett 2017. [DOI: 10.1016/j.tetlet.2016.12.057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Das D, Chakraborty TK. Radical Approach to the Chiral Quaternary Center in Asperaculin A: Synthesis of 9-Deoxyasperaculin A. Org Lett 2017; 19:682-685. [DOI: 10.1021/acs.orglett.6b03854] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dipendu Das
- CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
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7
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Du MR, Zhang XB, Si SM, Yang F, Wang L. Theoretical insights into C–C bond formation through isonitrile insertion into a Cp*Ti complex. RSC Adv 2017. [DOI: 10.1039/c7ra05680j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Reaction of Cp*(Cl)Ti(2,3-dimethylbutadiene) with isonitriles is studied using DFT, detailed elementary reaction steps and N-substitution effects of isonitrile are examined.
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Affiliation(s)
- Ming-Ran Du
- School of Chemical Engineering
- Anhui University of Science and Technology
- Huainan 232001
- People's Republic of China
| | - Xiang-Biao Zhang
- School of Chemical Engineering
- Anhui University of Science and Technology
- Huainan 232001
- People's Republic of China
| | - Sheng-Meng Si
- School of Chemical Engineering
- Anhui University of Science and Technology
- Huainan 232001
- People's Republic of China
| | - Feng Yang
- School of Chemical Engineering
- Anhui University of Science and Technology
- Huainan 232001
- People's Republic of China
| | - Lei Wang
- Department of Chemistry
- Huaibei Normal University
- Huaibei
- People's Republic of China
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Brambilla M, Davies SG, Fletcher AM, Roberts PM, Thomson JE. Asymmetric syntheses of the 1-hydroxymethyl-2-hydroxy substituted pyrrolizidines (−)-macronecine, (−)-petasinecine, (−)-1- epi -macronecine, (+)-1- epi -petasinecine and (+)-2- epi -rosmarinecine. Tetrahedron 2016. [DOI: 10.1016/j.tet.2016.09.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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9
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Das D, Chakraborty TK. An overview of the recent synthetic studies toward penifulvins and other fenestranes. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2016.07.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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10
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Martinez ST, Belouezzane C, Pinto AC, Glasnov T. Synthetic Strategies towards the Azabicyclo[3.3.0]-Octane Core of Natural Pyrrolizidine Alkaloids. An Overview. ORG PREP PROCED INT 2016. [DOI: 10.1080/00304948.2016.1165058] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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11
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Morcillo SP, Miguel D, Campaña AG, Álvarez de Cienfuegos L, Justicia J, Cuerva JM. Recent applications of Cp2TiCl in natural product synthesis. Org Chem Front 2014. [DOI: 10.1039/c3qo00024a] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Titanocene(iii)-based approaches have been demonstrated to be useful in the straightforward syntheses of many natural products from readily available starting materials.
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Affiliation(s)
- Sara P. Morcillo
- Department of Organic Chemistry
- University of Granada
- Granada 18071, Spain
| | - Delia Miguel
- Department of Organic Chemistry
- University of Granada
- Granada 18071, Spain
| | - Araceli G. Campaña
- Department of Organic Chemistry
- University of Granada
- Granada 18071, Spain
| | | | - José Justicia
- Department of Organic Chemistry
- University of Granada
- Granada 18071, Spain
| | - Juan M. Cuerva
- Department of Organic Chemistry
- University of Granada
- Granada 18071, Spain
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