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Song L, Zhou Y, Liang H, Li H, Lai Y, Yao H, Lin R, Tong R. Two Green Protocols for Halogenative Semipinacol Rearrangement. J Org Chem 2023; 88:504-512. [PMID: 36480595 DOI: 10.1021/acs.joc.2c02496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Semipinacol rearrangement is a special type of Wagner-Meerwein rearrangement that involves carbocation 1,2-rearrangement to provide carbonyl compounds with an α-quaternary carbon center. It has been strategically used for natural product synthesis and construction of highly congested quaternary carbons. Herein, we report a safe and green protocol that uses oxone/halide and Fenton bromide to achieve halogenative semipinacol rearrangement. The key feature of this method is the green in situ generation of reactive halogenating species from oxidation of halide with oxone or H2O2, which produces a nontoxic byproduct (potassium sulfate or water). Easy operation (insensitive to air and moisture) at room temperature without using special equipment adds additional advantage over previous methods.
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Affiliation(s)
- Liyan Song
- Key Laboratory of Biopesticide and Chemical Biology (Ministry of Education), College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Yiqin Zhou
- Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong 999077, China
| | - Hanbin Liang
- Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong 999077, China
| | - Hongzuo Li
- Key Laboratory of Biopesticide and Chemical Biology (Ministry of Education), College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Yunrong Lai
- Key Laboratory of Biopesticide and Chemical Biology (Ministry of Education), College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Hongliang Yao
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, Guangdong 510275, China
| | - Ran Lin
- Key Laboratory of Biopesticide and Chemical Biology (Ministry of Education), College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Rongbiao Tong
- Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong 999077, China.,Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, Guangdong 510275, China
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2
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Natho P, Allen LA, Parsons PJ. Recent advances in the ring expansion of cyclobutanols, oxetanols, and azetidinols. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.151695] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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3
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Verhoeven J, De Vleeschouwer F, Kong H, Van Hecke K, Pande V, Sun W, Vos A, Wu T, Meerpoel L, Thuring JW, Verniest G. Preparation of 4'-Spirocyclobutyl Nucleoside Analogues as Novel and Versatile Adenosine Scaffolds. Chemistry 2019; 25:15419-15423. [PMID: 31609050 DOI: 10.1002/chem.201904574] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Indexed: 11/10/2022]
Abstract
Despite the large variety of modified nucleosides that have been reported, the preparation of constrained 4'-spirocyclic adenosine analogues has received very little attention. We discovered that the [2+2]-cycloaddition of dichloroketene on readily available 4'-exo-methylene furanose sugars efficiently results in the diastereoselective formation of novel 4'-spirocyclobutanones. The reaction mechanism was investigated via density functional theory (DFT) and found to proceed either via a non-synchronous or stepwise reaction sequence, controlled by the stereochemistry at the 3'-position of the sugar substrate. The obtained dichlorocyclobutanones were converted into nucleoside analogues, providing access to a novel class of chiral 4'-spirocyclobutyl adenosine mimetics in eight steps from commercially available sugars. Assessment of the biological activity of designed 4'-spirocyclic adenosine analogues identified potent inhibitors for protein methyltransferase target PRMT5.
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Affiliation(s)
- Jonas Verhoeven
- Research Group of Organic Chemistry (ORGC), Department of Chemistry and Department of Bio-engineering Sciences, Faculty of Science and Bio-engineering Sciences, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium
| | - Freija De Vleeschouwer
- Research Group of Organic Chemistry (ORGC), Department of Chemistry and Department of Bio-engineering Sciences, Faculty of Science and Bio-engineering Sciences, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium.,Research Group of General Chemistry (ALGC), Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium
| | - Hanchu Kong
- Department of Synthetic Chemistry, Pharmaron Beijing Co., Ltd., 6 Taihe Road BDA, Beijing, 100176, P. R. China
| | - Kristof Van Hecke
- Department of Chemistry, Ghent University, Krijgslaan 281-S3, 9000, Ghent, Belgium
| | - Vineet Pande
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340, Beerse, Belgium
| | - Weimei Sun
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340, Beerse, Belgium
| | - Ann Vos
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340, Beerse, Belgium
| | - Tongfei Wu
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340, Beerse, Belgium
| | - Lieven Meerpoel
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340, Beerse, Belgium
| | | | - Guido Verniest
- Research Group of Organic Chemistry (ORGC), Department of Chemistry and Department of Bio-engineering Sciences, Faculty of Science and Bio-engineering Sciences, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium.,Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340, Beerse, Belgium
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6
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Hunter AC, Schlitzer SC, Stevens JC, Almutwalli B, Sharma I. A Convergent Approach to Diverse Spiroethers through Stereoselective Trapping of Rhodium Carbenoids with Gold-Activated Alkynols. J Org Chem 2018; 83:2744-2752. [DOI: 10.1021/acs.joc.7b03196] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Arianne C. Hunter
- Department of Chemistry and
Biochemistry, and Institute of Natural Products Applications and Research
Technologies, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73071,United States
| | - Steven C. Schlitzer
- Department of Chemistry and
Biochemistry, and Institute of Natural Products Applications and Research
Technologies, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73071,United States
| | - Joseph C. Stevens
- Department of Chemistry and
Biochemistry, and Institute of Natural Products Applications and Research
Technologies, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73071,United States
| | - Bilal Almutwalli
- Department of Chemistry and
Biochemistry, and Institute of Natural Products Applications and Research
Technologies, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73071,United States
| | - Indrajeet Sharma
- Department of Chemistry and
Biochemistry, and Institute of Natural Products Applications and Research
Technologies, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73071,United States
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7
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Sun J, Zheng G, Fu Y, Zhang Q, Wang Y, Zhang Q, Li Y, Zhang Q. Copper-catalyzed tandem radical amination/1,2-carbon migration of allylic alcohols: Direct access to α-quaternary-β-amino ketones. CHINESE JOURNAL OF CATALYSIS 2018. [DOI: 10.1016/s1872-2067(18)63028-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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8
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Lempenauer L, Duñach E, Lemière G. Tuning the Reactivity of Functionalized Diallylic Alcohols: Brønsted versus Lewis Acid Catalysis. Chemistry 2017; 23:10285-10288. [DOI: 10.1002/chem.201702601] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Luisa Lempenauer
- Université Côte d'AzurInstitut de Chimie de Nice, CNRS, Parc Valrose 06108 Nice Cedex 2 France
| | - Elisabet Duñach
- Université Côte d'AzurInstitut de Chimie de Nice, CNRS, Parc Valrose 06108 Nice Cedex 2 France
| | - Gilles Lemière
- Université Côte d'AzurInstitut de Chimie de Nice, CNRS, Parc Valrose 06108 Nice Cedex 2 France
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9
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Facile Synthesis of 3-Halobenzo-heterocyclic-2-carbonyl Compoundsviain situ Halogenation-Oxidation. Adv Synth Catal 2016. [DOI: 10.1002/adsc.201600431] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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11
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Lempenauer L, Duñach E, Lemière G. Catalytic Rearrangement of 2-Alkoxy Diallyl Alcohols: Access to Polysubstituted Cyclopentenones. Org Lett 2016; 18:1326-9. [DOI: 10.1021/acs.orglett.6b00270] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Luisa Lempenauer
- Institut de Chimie de Nice,
UMR 7272,
Université Nice Sophia Antipolis, CNRS, Parc
Valrose, 06108 Nice Cedex 2, France
| | - Elisabet Duñach
- Institut de Chimie de Nice,
UMR 7272,
Université Nice Sophia Antipolis, CNRS, Parc
Valrose, 06108 Nice Cedex 2, France
| | - Gilles Lemière
- Institut de Chimie de Nice,
UMR 7272,
Université Nice Sophia Antipolis, CNRS, Parc
Valrose, 06108 Nice Cedex 2, France
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12
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Huang H, Yang Q, Zhang Q, Wu J, Liu Y, Song C, Chang J. A Hofmann Rearrangement-Ring Expansion Cascade for the Synthesis of 1-Pyrrolines: Application to the Synthesis of 2,3-Dihydro-1H-pyrrolo[2,1-a]isoquinolinium Salts. Adv Synth Catal 2016. [DOI: 10.1002/adsc.201501071] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Abstract
In connection with its first synthesis, plakinidone was structurally revised to a five-membered lactone. The key evidence for the previous assignment of this natural product as a perlactone was proven to be a misinterpretation of the MS data because of unawareness of a facile air oxidation. The synthetic samples also allowed for detection of differences in (13)C NMR for diastereomers of remote stereogenic centers, along with the influence of the air oxidation on the optical rotation.
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Affiliation(s)
- Ze-Jun Xu
- State Key Laboratory of Bioorganic and Natural Product Chemistry, Collective Innovative Center for Chemistry and Life Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , 345 Lingling Road, Shanghai 200032, China
| | - Dong-Xing Tan
- State Key Laboratory of Bioorganic and Natural Product Chemistry, Collective Innovative Center for Chemistry and Life Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , 345 Lingling Road, Shanghai 200032, China
| | - Yikang Wu
- State Key Laboratory of Bioorganic and Natural Product Chemistry, Collective Innovative Center for Chemistry and Life Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , 345 Lingling Road, Shanghai 200032, China
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14
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Stereocontrolled synthesis and functionalization of cyclobutanes and cyclobutanones. Molecules 2013; 18:15541-72. [PMID: 24352013 PMCID: PMC6269998 DOI: 10.3390/molecules181215541] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 12/09/2013] [Accepted: 12/11/2013] [Indexed: 02/02/2023] Open
Abstract
In the last decade a certain number of new cyclobutane and cyclobutanone synthesis and functionalization protocols have been published. Organo- and biocatalyzed eco-friendly approaches to cyclobutane-containing molecules have been developed with interesting results. Also, successful new total synthesis of bioactive compounds and drugs have been recently reported where a four membered ring represented the key intermediate. Therefore, the rising interest in this field represents a great point of discussion for the scientific community, disclosing the synthetic potential of strained four membered ring carbocyclic compounds. Herein we report a critical survey on the literature concerning the enantiocontrolled synthesis and functionalization of cyclobutane derivatives, with particular attention to metal-free, low impact methodologies, published during the period 2000-2013.
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Chen ZM, Bai W, Wang SH, Yang BM, Tu YQ, Zhang FM. Copper-Catalyzed Tandem Trifluoromethylation/Semipinacol Rearrangement of Allylic Alcohols. Angew Chem Int Ed Engl 2013; 52:9781-5. [DOI: 10.1002/anie.201304557] [Citation(s) in RCA: 224] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Indexed: 11/06/2022]
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16
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Chen ZM, Bai W, Wang SH, Yang BM, Tu YQ, Zhang FM. Copper-Catalyzed Tandem Trifluoromethylation/Semipinacol Rearrangement of Allylic Alcohols. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201304557] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Zhang XL, Liao YQ, Cai PJ, Yao HQ, Kong LY, Sun HB. Synthesis of A B C-ring subunit of C-nor-D-homo-steroidal alkaloids: towards the total synthesis of cyclopamine. Chin J Nat Med 2013; 11:277-83. [PMID: 23725842 DOI: 10.1016/s1875-5364(13)60029-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Indexed: 10/25/2022]
Abstract
A practical approach to the synthesis of the A, B and C-ring subunit of cyclopamine has been developed. This synthetic tactic highlights the utility of mandelate acetal-mediated resolution of the fused ring ketone (±)-4 and IBX-mediated oxidation cascades from 12 to 9. The availability of advanced intermediates from enantiomerically pure (+)-4 and 2 could provide efficient access to biologically active and structurally diverse C-nor-D-homo-steroidal alkaloids such as cyclopamine.
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Affiliation(s)
- Xue-Li Zhang
- Center for Drug Discovery, College of Pharmacy, China Pharmaceutical University, Nanjing, China
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Chen ZM, Yang BM, Chen ZH, Zhang QW, Wang M, Tu YQ. Organocatalytic Asymmetric Fluorination/Semipinacol Rearrangement: An Efficient Approach to Chiral β-Fluoroketones. Chemistry 2012; 18:12950-4. [DOI: 10.1002/chem.201202444] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Indexed: 11/09/2022]
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Jiao ZW, Zhang SY, He C, Tu YQ, Wang SH, Zhang FM, Zhang YQ, Li H. Organocatalytic Asymmetric Direct C sp 3H Functionalization of Ethers: A Highly Efficient Approach to Chiral Spiroethers. Angew Chem Int Ed Engl 2012; 51:8811-5. [DOI: 10.1002/anie.201204274] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Indexed: 11/05/2022]
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20
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Jiao ZW, Zhang SY, He C, Tu YQ, Wang SH, Zhang FM, Zhang YQ, Li H. Organocatalytic Asymmetric Direct C sp 3H Functionalization of Ethers: A Highly Efficient Approach to Chiral Spiroethers. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201204274] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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21
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Kim KD, Yeom HS, Shin S, Shin S. Gold-catalyzed ring expansions of 1-alkynylcyclobutanol derivatives via tandem hydration and α-ketol rearrangement. Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.03.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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22
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Wang B, Tu YQ. Stereoselective construction of quaternary carbon stereocenters via a semipinacol rearrangement strategy. Acc Chem Res 2011; 44:1207-22. [PMID: 21728380 DOI: 10.1021/ar200082p] [Citation(s) in RCA: 319] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Quaternary carbon stereocenters are found in a broad range of organic compounds, including important bioactive natural products and medicinal agents. Given their ubiquity and the significant synthetic challenges they present, quaternary carbon stereocenters have long attracted great interest from synthetic organic chemists. Numerous efforts have been devoted to their construction, leading to a spectrum of strategies for creating stereogenic quaternary carbon centers. In this context, the semipinacol rearrangement has proven successful. In this extension of the pinacol rearrangement, the 1,2-carbon-to-carbon migration in a 1,2-diol has been expanded to include leaving groups other than the hydroxyl group. Over the past decade, our laboratory has explored the semipinacol rearrangement strategy for the stereoselective construction of quaternary carbon stereocenters. We have investigated various substrates, including 2,3-epoxy alcohols (also termed α-hydroxy epoxides), 2,3-aziridino alcohols, and allylic alcohols. Several promoters that effect the semipinacol rearrangement have been identified, including Lewis acids based on Al, Sm, B, Zn, and Ti for the rearrangement of α-hydroxy epoxides and 2,3-aziridino alcohols; cationic halogen species for the rearrangement of allylic alcohols; and cinchona alkaloids and chiral phosphoric acid for the asymmetric semipinacol rearrangement. Our research efforts have led to a series of valuable synthetic methods, including (1) a tandem semipinacol rearrangement and Meerwein-Ponndorf-Verley reduction, (2) a tandem semipinacol rearrangement and Tishchenko reaction, (3) a tandem semipinacol rearrangement with either an allylation or a propargylation, (4) a tandem semipinacol rearrangement and Schmidt reaction, (5) a semipinacol rearrangement of 2,3-aziridino alcohols, (6) a semipinacol rearrangement of allylic alcohols induced by halogen cation, (7) a tandem aziridination and semipinacol rearrangement of allylic alcohols, and (8) asymmetric semipinacol rearrangements with chiral organic catalysts. One hallmark of these reactions is the creation of stereogenic quaternary carbon centers with high levels of stereocontrol. In this Account, we describe the development of these synthetically useful methodologies and their successful application to the total syntheses of natural products. Our results demonstrate that the semipinacol rearrangement of carefully designed substrates constitutes an efficient approach to the stereoselective construction of quaternary carbon centers. These reactions have produced a broad array of useful compounds that lend themselves to further elaboration. Furthermore, the total synthesis of a series of alkaloids, with significant bioactivity and intriguing molecular architecture, was achieved through these semipinacol rearrangement strategies, highlighting their synthetic value.
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Affiliation(s)
- Baomin Wang
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou 730000, P. R. China
- State Key Laboratory of Fine Chemicals and School of Pharmaceutical Science and Technology, Dalian University of Technology, Dalian 116024, P. R. China
| | - Yong Qiang Tu
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou 730000, P. R. China
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23
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Song ZL, Fan CA, Tu YQ. Semipinacol Rearrangement in Natural Product Synthesis. Chem Rev 2011; 111:7523-56. [PMID: 21851053 DOI: 10.1021/cr200055g] [Citation(s) in RCA: 385] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Zhen-Lei 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
- State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, P. R. China
| | - Chun-An Fan
- State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, P. R. China
| | - Yong-Qiang Tu
- State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, P. R. China
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Li BS, Zhang E, Zhang QW, Zhang FM, Tu YQ, Cao XP. One-Pot Construction of Multi-Substituted Spiro-Cycloalkanediones by an Organocatalytic Asymmetric Epoxidation/Semipinacol Rearrangement. Chem Asian J 2011; 6:2269-72. [DOI: 10.1002/asia.201100383] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Indexed: 11/05/2022]
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25
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Chen ZM, Zhang QW, Chen ZH, Li H, Tu YQ, Zhang FM, Tian JM. Organocatalytic asymmetric halogenation/semipinacol rearrangement: highly efficient synthesis of chiral α-oxa-quaternary β-haloketones. J Am Chem Soc 2011; 133:8818-21. [PMID: 21548637 DOI: 10.1021/ja201794v] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel asymmetric halogenation/semipinacol rearrangement reaction catalyzed by cinchona alkaloid derivatives was developed. Two types of β-haloketones (X = Br, Cl) were obtained with up to 95% yield and 99% enantiomeric excess. The desired (+) and (-) enantiomers of the β-haloketones were readily obtained.
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Affiliation(s)
- Zhi-Min Chen
- State Key Laboratory of Applied Organic Chemistry & Department of Chemistry, Lanzhou University, Lanzhou 730000, PR China
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Leemans E, D’hooghe M, De Kimpe N. Ring Expansion of Cyclobutylmethylcarbenium Ions to Cyclopentane or Cyclopentene Derivatives and Metal-Promoted Analogous Rearrangements. Chem Rev 2011; 111:3268-333. [DOI: 10.1021/cr100295j] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Erika Leemans
- Department of Sustainable Organic Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
| | - Matthias D’hooghe
- Department of Sustainable Organic Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
| | - Norbert De Kimpe
- Department of Sustainable Organic Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
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Li H, Zhang FM, Tu YQ, Zhang QW, Chen ZM, Chen ZH, Li J. Enantioselective bromination/semipinacol rearrangement for the synthesis of β-bromoketones containing an all-α-carbon quaternary center. Chem Sci 2011. [DOI: 10.1039/c1sc00295c] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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28
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Huang D, Yan M, Zhao WJ, Shen Q. 1,3-dipolar addition of methyl α-diazoacetoacetate to enamines: A new synthetic route to 5-amino-4,5-dihydrofurans. CHINESE J CHEM 2010. [DOI: 10.1002/cjoc.20040221206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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29
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Lebreton J, Escudier JM, Arzel L, Len C. Synthesis of Bicyclonucleosides Having a C−C Bridge. Chem Rev 2010; 110:3371-418. [DOI: 10.1021/cr800465j] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Jacques Lebreton
- Université de Nantes, CNRS, Laboratoire CEISAM-UMR-CNRS 6230, Faculté des Sciences et des Techniques, 2 rue de la Houssinière, BP 92208, 44322 Nantes Cedex 3, France, Université Paul Sabatier Laboratoire de Synthèse et Physicochimie des Molécules d’Intérêt Biologique - UMR-CNRS 5068, 31062 Toulouse Cedex, France, and Université de Technologie de Compiègne, Ecole Supérieure de Chimie Organique Minérale, EA 4297, Transformations Intégrées de la Matière Renouvelable, 1 allée du Réseau Jean-Marie Buckmaster,
| | - Jean-Marc Escudier
- Université de Nantes, CNRS, Laboratoire CEISAM-UMR-CNRS 6230, Faculté des Sciences et des Techniques, 2 rue de la Houssinière, BP 92208, 44322 Nantes Cedex 3, France, Université Paul Sabatier Laboratoire de Synthèse et Physicochimie des Molécules d’Intérêt Biologique - UMR-CNRS 5068, 31062 Toulouse Cedex, France, and Université de Technologie de Compiègne, Ecole Supérieure de Chimie Organique Minérale, EA 4297, Transformations Intégrées de la Matière Renouvelable, 1 allée du Réseau Jean-Marie Buckmaster,
| | - Laurence Arzel
- Université de Nantes, CNRS, Laboratoire CEISAM-UMR-CNRS 6230, Faculté des Sciences et des Techniques, 2 rue de la Houssinière, BP 92208, 44322 Nantes Cedex 3, France, Université Paul Sabatier Laboratoire de Synthèse et Physicochimie des Molécules d’Intérêt Biologique - UMR-CNRS 5068, 31062 Toulouse Cedex, France, and Université de Technologie de Compiègne, Ecole Supérieure de Chimie Organique Minérale, EA 4297, Transformations Intégrées de la Matière Renouvelable, 1 allée du Réseau Jean-Marie Buckmaster,
| | - Christophe Len
- Université de Nantes, CNRS, Laboratoire CEISAM-UMR-CNRS 6230, Faculté des Sciences et des Techniques, 2 rue de la Houssinière, BP 92208, 44322 Nantes Cedex 3, France, Université Paul Sabatier Laboratoire de Synthèse et Physicochimie des Molécules d’Intérêt Biologique - UMR-CNRS 5068, 31062 Toulouse Cedex, France, and Université de Technologie de Compiègne, Ecole Supérieure de Chimie Organique Minérale, EA 4297, Transformations Intégrées de la Matière Renouvelable, 1 allée du Réseau Jean-Marie Buckmaster,
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30
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Zhang QW, Fan CA, Zhang HJ, Tu YQ, Zhao YM, Gu P, Chen ZM. Brønsted Acid Catalyzed Enantioselective Semipinacol Rearrangement for the Synthesis of Chiral Spiroethers. Angew Chem Int Ed Engl 2009; 48:8572-4. [DOI: 10.1002/anie.200904565] [Citation(s) in RCA: 188] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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31
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Zhang QW, Fan CA, Zhang HJ, Tu YQ, Zhao YM, Gu P, Chen ZM. Brønsted Acid Catalyzed Enantioselective Semipinacol Rearrangement for the Synthesis of Chiral Spiroethers. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200904565] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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32
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Song F, Liu Y. A facile approach to spirocyclic butenolides through cascade cyclization/oxidative cleavage reactions of (Z)-enynols catalyzed by gold under dioxygen atmosphere. J Organomet Chem 2009. [DOI: 10.1016/j.jorganchem.2008.10.046] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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33
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Hurley PB, Dake GR. Synthetic Studies toward Halichlorine: Complex Azaspirocycle Formation with Use of an NBS-Promoted Semipinacol Reaction. J Org Chem 2008; 73:4131-8. [DOI: 10.1021/jo800336k] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paul B. Hurley
- Department of Chemistry, 2036 Main Mall, University of British Columbia, Vancouver, B.C., Canada V6T 1Z1
| | - Gregory R. Dake
- Department of Chemistry, 2036 Main Mall, University of British Columbia, Vancouver, B.C., Canada V6T 1Z1
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34
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Maulide N, Markó IE. 2-(Trimethylsilyloxy)furan as a Dianion Equivalent: A Two-Step Synthesis of Functionalized Spirocyclic Butenolides. Org Lett 2006; 8:3705-7. [PMID: 16898797 DOI: 10.1021/ol061284g] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] The use of 2-(trimethylsilyloxy)furan derivatives as dianion equivalents leads to a general and connective spiroannulation protocol for the efficient preparation of spirocyclic butenolides.
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Affiliation(s)
- Nuno Maulide
- Université catholique de Louvain, Département de Chimie, 1 Place Louis Pasteur, B-1348 Louvain-la-Neuve, Belgium
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35
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Dong S, Paquette LA. Highly Stereoselective β-Anomeric Glycosidation of a 2‘-Deoxy Syn-5‘-Configured 4‘-Spironucleoside. J Org Chem 2006; 71:1647-52. [PMID: 16468819 DOI: 10.1021/jo052324h] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A direct enantioselective pathway that delivers exclusively the beta-anomer of a 4'-spironucleoside has been successfully developed. The key starting material is the enantiomerically pure dihydroxy lactone 19, which has proven amenable to conversion to glycal 22 via the chloro acetonide. This intermediate is then capped as the 3,5-O-(tetraisopropyldisiloxane-1,3-diyl) glycal. The latter can enter into N-iodosuccinimide-promoted glycosidation with persilylated thymine. Only the beta anomer is formed. Ensuing deiodination and desilylation proceed quantitatively to furnish the targeted, previously elusive anomer.
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Affiliation(s)
- Shuzhi Dong
- Evans Chemical Laboratories, Ohio State University, Columbus, Ohio 43210, USA
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36
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Jain N, Xu J, Chen N, Sui Z. A novel approach to the synthesis of 11,11-dimethyl-bisbenzopyran-5-ones. Tetrahedron Lett 2006. [DOI: 10.1016/j.tetlet.2005.10.150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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37
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Fan CA, Tu YQ, Song ZL, Zhang E, Shi L, Wang M, Wang B, Zhang SY. An Efficient Total Synthesis of (±)-Lycoramine. Org Lett 2004; 6:4691-4. [PMID: 15575662 DOI: 10.1021/ol048105k] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] A short and unique approach to (+/-)-lycoramine as one of the galanthamine-type alkaloids has been efficiently developed. The alternative advantage lies in that three stereocenters, including a crucial quaternary carbon center, were constructed with high diasteroselectivity via a key one-step NBS-mediated semipinacol rearrangement of the allylic alcohol.
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Affiliation(s)
- Chun-An Fan
- State Key Laboratory of Applied Organic Chemistry & Department of Chemistry, Lanzhou University, Lanzhou 730000, PR China
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38
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Paquette LA, Seekamp CK, Kahane AL, Hilmey DG, Gallucci J. Stereochemical Features of Lewis Acid-Promoted Glycosidations Involving 4‘-Spiroannulated DNA Building Blocks. J Org Chem 2004; 69:7442-7. [PMID: 15497968 DOI: 10.1021/jo048904g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tin tetrachloride-catalyzed glycosidation of persilylated nucleobases with acetate donor 6 in CH(2)Cl(2) solution followed by deprotection gave rise very predominantly to alpha-spironucleosides. These stereochemical assignments stem from the determination of NOE interactions and an X-ray crystallographic analysis of the latter product. Computational studies revealed that these results are consistent with the fact that the C5' substituent shields the beta-face of the oxonium ion involved in the coupling reaction while the C3' substituent is projected away from the alpha-underside. Attack from the more open direction is therefore kinetically favored. Entirely comparable calculations suggested that donor 19 should behave comparably. Experimentation involving this donor gave results consistent with this model although more equitable alpha/beta spironucleoside product ratios were seen when acetonitrile was employed as the reaction medium.
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Affiliation(s)
- Leo A Paquette
- Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA.
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39
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Paquette LA, Kahane AL, Seekamp CK. Conformationally Constrained Purine Mimics. Incorporation of Adenine and Guanine into Spirocyclic Nucleosides. J Org Chem 2004; 69:5555-62. [PMID: 15307723 DOI: 10.1021/jo049413z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Directed syntheses of spirocyclic nucleosides featuring adenine and guanine as the nucleobases have been successfully developed. The key starting materials are the enantiomerically pure spiro lactones 4, 15, and 28, which have proven amenable to conversion to anomeric mixtures of chloro sugars. The latter can enter into glycosidation by SN2 displacement with the sodium salts of 6-chloropurine or 2-amino-6-chloropurine. In the saturated series, the chromatographic separation of 18 from 19 was possible. Where 33 and 34 are concerned, their relatively rapid rate of epimerization precluded this. Mimics 35-37 resisted isolation as pure anomers. The configurational assignments are based on the thermal interconversions and supporting MM3 steric energy calculations. Added corroboration was gained from a crystallographic analysis of 8. Although removal of the TBS protecting groups in all late-stage guanine intermediates proved to be problematical, the pair of hydroxyl groups in 37 could be introduced by proper recourse to the oxidation of 36 with ruthenium tetraoxide.
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Affiliation(s)
- Leo A Paquette
- Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA.
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40
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Gais HJ, Reddy LR, Babu GS, Raabe G. Asymmetric Synthesis of 2,3-Dihydrofurans and of Unsaturated Bicyclic Tetrahydrofurans through α-Elimination and Migratory Cyclization of Silyloxy Alkenyl Aminosulfoxonium Salts. Generation and Intramolecular O,Si-Bond Insertion of Chiral Disubstituted β-Silyloxy Alkylidene Carbenes. J Am Chem Soc 2004; 126:4859-64. [PMID: 15080690 DOI: 10.1021/ja030501v] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Treatment of the bis(allylsulfoximine)titanium complexes derived from the beta-methyl-substituted acyclic allylic sulfoximines 13a and 13b with aldehydes gave with high selectivities the corresponding sulfoximine-substituted homoallylic alcohols which were isolated as the silyl ethers 15a-h. Methylation of sulfoximines 15a-h afforded the aminosulfoxonium salts 5a-h which upon treatment with LiN(H)tBu gave in high yields the enantio- and diastereomerically pure silyl-substituted 2,3-dihydrofurans 4a-h. Treatment of the titanium complexes derived from the cyclic allylic sulfoximines 17a, 17b, and ent-17c with p-MeOC(6)H(4)CHO delivered with high selectivities the corresponding sulfoximine-substituted cyclic homoallylic alcohols which were isolated as the silyl ethers 18a, 18b, and ent-18c, respectively. Methylation of sulfoximines 18a, 18b, and ent-18c furnished the aminosulfoxonium salts 8a, 8b, and ent-8c, respectively, whose treatment with LiN(H)t-Bu gave the enantio- and diastereomerically pure fused bicyclic 2,3-dihydrofurans 6a, 6b, and ent-6c, respectively, in good yields. It is proposed that the 1-alkenyl aminosulfoxonium salts 5a-h, 8a, 8b, and ent-8c react with the base under alpha-elimination and formation of the acyclic and cyclic beta-silyloxy alkylidene carbenes 2a-h, 7a, 7b, and ent-7c, respectively, which then undergo a 1,5-O,Si-bond insertion and 1,2-silyl migration. The cyclic aminosulfoxonium salts 8a, 8b, and ent-8c upon treatment with 1,8-diazabicyclo[5.4.0]-7-undecene did not undergo an alpha-elimination but suffered a novel migratory cyclization with formation of the enantio- and diastereomerically pure bicyclic tetrahydrofurans 9a, 9b, and ent-9c, respectively. It is proposed that the 1-alkenyl sulfoxonium salts 8a, 8b, and ent-8c are isomerized to the allylic aminosulfoxonium salts 10a, 10b, and ent-10c, respectively, which then suffer an intramolecular substitution of the (dimethylamino)sulfoxonium group by the silyloxy group followed by a desilylation. The syntheses of the 2,3-dihydrofurans 4a-h, 6a, and 6b and of the tetrahydrofurans 9a and 9b are accompanied by the formation of sulfinamide 16 of >or=98% ee, which can be converted via sulfoxide 28 of >or=98% to the starting sulfoximine 11 of >or=98% ee.
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Affiliation(s)
- Hans-Joachim Gais
- Institut für Organische Chemie der Rheinisch-Westfälischen Technischen Hochschule (RWTH) Aachen, Prof.-Pirlet-Strasse 1, D-52056 Aachen, Germany.
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41
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Paquette LA, Seekamp CK, Kahane AL. Conformational Restriction of Nucleosides by Spirocyclic Annulation at C4‘ Including Synthesis of the Complementary Dideoxy and Didehydrodideoxy Analogues. J Org Chem 2003; 68:8614-24. [PMID: 14575494 DOI: 10.1021/jo0301954] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The concept of spirocyclic restriction, when generically applied to nucleoside mimics, allows for the preparation of diastereomeric pairs carrying either a syn- or anti-oriented hydroxyl at C-5'. Reported herein are convenient synthetic routes to enantiomerically pure 1-oxaspiro[4.4]nonanes featuring fully dihydroxylated end products as well as congeners having dideoxy and didehydrodideoxy substitution patterns. Notable use is made of the capacity for introducing unsaturation in the furanose sector via phenylsulfenylation and the incorporation of uracil and thymine by way of their silylated derivatives under catalysis with stannic chloride.
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Affiliation(s)
- Leo A Paquette
- Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA.
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42
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Paquette LA, Fabris F, Gallou F, Dong S. C4‘-Spiroalkylated Nucleosides Having Sulfur Incorporated at the Apex Position. J Org Chem 2003; 68:8625-34. [PMID: 14575495 DOI: 10.1021/jo030196w] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Methodology based on the concept of thionium ion-initiated pinacolic ring expansion has been developed for accessing C4'-spirocyclic thionucleosides. The readily available racemic ketones 6 and 37 are conveniently resolved via their acetals with (R)-mandelic acid. Subsequent reactions beginning with utilization of the Pummerer rearrangement lend themselves to functionalization of the spirocyclic core and ultimately incorporation of the nucleosidic bases. Limitations to this strategy are pointed out. Acquisition of the alpha- and beta-isomers at C4' is equally facile. Absolute configurational assignments have been made possible by X-ray crystallography.
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Affiliation(s)
- Leo A Paquette
- Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA.
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43
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Eipert M, Maichle-Mössmer C, Maier ME. Use of epoxidation and epoxide opening reactions for the synthesis of highly functionalized 1-oxaspiro[4.5]decan-2-ones and related compounds. Tetrahedron 2003. [DOI: 10.1016/j.tet.2003.08.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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44
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Paju A, Kanger T, Niitsoo O, Pehk T, Müürisepp AM, Lopp M. Asymmetric oxidation of 3-alkyl-1,2-cyclopentanediones. Part 3: Oxidative ring cleavage of 3-hydroxyethyl-1,2-cyclopentanediones: synthesis of α-hydroxy-γ-lactone acids and spiro-γ-dilactones. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0957-4166(03)00452-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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45
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Namyslo JC, Kaufmann DE. The application of cyclobutane derivatives in organic synthesis. Chem Rev 2003; 103:1485-537. [PMID: 12683789 DOI: 10.1021/cr010010y] [Citation(s) in RCA: 532] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jan C Namyslo
- Institut für Organische Chemie, Technische Universität Clausthal, 38678 Clausthal-Zellerfeld, Germany
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46
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Paquette LA, Hartung RE, France DJ. Conversion of the enantiomers of spiro[4.4]nonane-1,6-diol into both epimeric carbaspironucleosides having natural C1' absolute configuration. Org Lett 2003; 5:869-71. [PMID: 12633093 DOI: 10.1021/ol0340033] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text] The enantiomers of spiro[4.4]nonane-1,6-diol have been transformed by different reaction pathways into the two possible carbaspironucleoside epimers with natural C1' absolute stereochemistry.
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Affiliation(s)
- Leo A Paquette
- Department of Chemistry, Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA.
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47
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Paquette LA, Bibart RT, Seekamp CK, Kahane AL. Spirocyclic restriction of nucleosides. Synthesis of the first exemplary syn-1-oxaspiro[4.4]nonanyl member. Org Lett 2001; 3:4039-41. [PMID: 11735579 DOI: 10.1021/ol010209x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] The potential benefits associated with the spirocyclic restriction of nucleosides are summarized. Following exploration of a pi-allylpalladium route to 5'-alpha- or syn-dideoxy examples, we evaluated MOM protection of the 5'-hydroxyl as being suited to the synthesis of the first member of this new class of nucleoside mimic.
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Affiliation(s)
- L A Paquette
- Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA.
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48
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Paquette LA, Owen DR, Bibart RT, Seekamp CK. Spirocyclic restriction of nucleosides. An analysis of protecting group feasibility while accessing prototype anti-1-oxaspiro[4.4]nonanyl mimics. Org Lett 2001; 3:4043-5. [PMID: 11735580 DOI: 10.1021/ol010212g] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] The first spirocyclic nucleoside featuring a beta-hydroxyl (anti) at C5' has yielded to synthesis. While the OMOM functionality proved to be sensitive to the conditions necessary to incorporate heterocyclic bases, PMB protection of the carbinol was readily accommodated. The remarkably similar minimum-energy conformations of the title compounds relative to natural thymidine as deduced by Amber calculations in the gas phase are noted.
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Affiliation(s)
- L A Paquette
- Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA.
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49
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Fenster MD, Patrick BO, Dake GR. Construction of azaspirocyclic ketones through alpha-hydroxyiminium ion or alpha-siloxy epoxide semipinacol rearrangements. Org Lett 2001; 3:2109-12. [PMID: 11418061 DOI: 10.1021/ol0160708] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] Semipinacol-type rearrangements to produce azaspirocyclic ketones are presented. The yields and stereoselectivities of these reactions range from 67-94% yield and 2.8:1 to 1:0 diastereoselectivity, respectively.
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Affiliation(s)
- M D Fenster
- Department of Chemistry, 2036 Main Mall, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
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