1
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Lamhauge JN, McLeod DA, Barløse CL, Oliver GA, Viborg L, Warburg T, Anker Jørgensen K. Enantioselective Synthesis of Tropane Scaffolds by an Organocatalyzed 1,3-Dipolar Cycloaddition of 3-Oxidopyridinium Betaines and Dienamines. Chemistry 2023; 29:e202301830. [PMID: 37318111 DOI: 10.1002/chem.202301830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 06/15/2023] [Accepted: 06/15/2023] [Indexed: 06/16/2023]
Abstract
Tropane alkaloids constitute a compound-class which is structurally defined by a central 8-azabicyclo[3.2.1]octane core. A diverse bioactivity profile combined with an unusual aza-bridged bicyclic framework has made tropanes molecules-of-interest within organic chemistry. Enantioselective examples of (5+2) cycloadditions between 3-oxidopyridinium betaines and olefins remain unexplored, despite 3-oxidopyridinium betaines being useful reagents in organic synthesis. The first asymmetric (5+2) cycloaddition of 3-oxidopyridinium betaines is reported, affording tropane derivatives in up to quantitative yield and with excellent control of peri-, regio-, diastereo-, and enantioselectivity. The reactivity is enabled by dienamine-activation of α,β-unsaturated aldehydes combined with in situ formation of the pyridinium reaction-partner. A simple N-deprotection protocol allows for liberation of the tropane alkaloid motif, and synthetic elaborations of the cycloadducts demonstrate their synthetic utility to achieve highly diastereoselective modification around the bicyclic framework. DFT computations suggest a stepwise mechanism where regio- and stereoselectivity are defined during the first bond-forming step in which the pyridinium dipole exerts critical conformational control over its dienamine partner. In the second bond-forming step, a kinetic preference toward an initial (5+4) cycloadduct was identified; however, a lack of catalyst turn-over, reversibility, and thermodynamic bias favoring a (5+2) cycloadduct rendered the reaction fully periselective.
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Affiliation(s)
- Johannes N Lamhauge
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark
| | - David A McLeod
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark
| | - Casper L Barløse
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark
| | - Gwyndaf A Oliver
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark
| | - Laura Viborg
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark
| | - Tobias Warburg
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark
| | - Karl Anker Jørgensen
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark
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2
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Lu TY, Hsu WY, Huang BW, Han JL. Reagent-Controlled Regiodivergent Annulations of Achmatowicz Products with Vinylogous Nucleophiles: Synthesis of Bicyclic Cyclopenta[ b]pyrans and 8-Oxabicyclo[3.2.1]octane Derivatives. Org Lett 2022; 24:7806-7811. [PMID: 36259648 DOI: 10.1021/acs.orglett.2c03127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two reagent-controlled regiodivergent annulation protocols for Achmatowicz products with vinylogous nucleophiles have been developed, which furnished a series of bicyclic cyclopenta[b]pyrans and 8-oxabicyclo[3.2.1]octane derivatives in 28-90% yields. Plausible mechanisms were proposed to involve either Pd-catalyzed Tsuji-Trost allyl-allyl coupling and concomitant Michael cyclization or quinine-promoted cascade stepwise [5 + 2] cycloaddition and intramolecular Michael cyclization.
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Affiliation(s)
- Ting-Yu Lu
- Department of Chemistry, National Chung Hsing University, Taichung City 40227, Taiwan, Republic of China
| | - Wan-Yun Hsu
- Department of Chemistry, National Chung Hsing University, Taichung City 40227, Taiwan, Republic of China
| | - Bo-Wei Huang
- Department of Chemistry, National Chung Hsing University, Taichung City 40227, Taiwan, Republic of China
| | - Jeng-Liang Han
- Department of Chemistry, National Chung Hsing University, Taichung City 40227, Taiwan, Republic of China
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3
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Huang J, Jiang B, Zhang X, Gao Y, Xu X, Miao Z. Triethyamine‐promoted [5+3] Cycloadditions for Regio‐ and Diastereoselective Synthesis of Functionalized aza‐Bicyclo[3.3.1]alkenones. Adv Synth Catal 2022. [DOI: 10.1002/adsc.202200764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | | | | | | | | | - Zhiwei Miao
- Institute of Elemento-Organic Chemistry CHINA
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4
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Zhang X, Tong Y, Li G, Zhao H, Chen G, Yao H, Tong R. 1,5-Allyl Shift by a Sequential Achmatowicz/Oxonia-Cope/Retro-Achmatowicz Rearrangement. Angew Chem Int Ed Engl 2022; 61:e202205919. [PMID: 35670657 DOI: 10.1002/anie.202205919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Indexed: 12/12/2022]
Abstract
1,3-Allyl and 1,2-allyl shifts through [3,3]- and [2,3]-sigmatropic rearrangements are well-established and widely used in organic synthesis. In contrast, 1,5-allyl shift through related [3,5]-sigmatropic rearrangement is unknown because [3,5]-sigmatropic rearrangement is thermally Woodward-Hoffmann forbidden. Herein, we report an unexpected discovery of a formal 1,5-allyl shift of allyl furfuryl alcohol through a 2-step sequential rearrangement. Mechanistically, this formal 1,5-allyl shift is achieved through a sequential ring expansion/contraction rearrangement: 1) Achmatowicz rearrangement (ring expansion), and 2) cascade oxonia-Cope rearrangement/retro-Achmatowicz rearrangement (ring contraction). This new 1,5-allyl shift method is demonstrated with >20 examples and expected to find applications in organic synthesis and materials chemistry.
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Affiliation(s)
- Xiayan Zhang
- Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China.,Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China
| | - Yi Tong
- Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China
| | - Gang Li
- 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, 510260, China
| | - Hao Zhao
- 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, 510260, China
| | - Guanye Chen
- 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, 510260, 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, 510260, China
| | - Rongbiao Tong
- Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China.,Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, 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, 510260, China
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5
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Jia S, Tian Y, Li X, Wang P, Lan Y, Yan H. Atroposelective Construction of Nine-Membered Carbonate-Bridged Biaryls. Angew Chem Int Ed Engl 2022; 61:e202206501. [PMID: 35621411 DOI: 10.1002/anie.202206501] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Indexed: 12/27/2022]
Abstract
We herein demonstrated an efficient method for the atroposelective construction of nine-membered carbonate-bridged biaryls through vinylidene ortho-quinone methide (VQM) intermediates. Diverse products with desirable pharmacological features were synthesized in satisfying yields and good to excellent enantioselectivities. In subsequent bioassays, several agents showed considerable antiproliferative activity via the mitochondrial-related apoptosis mechanism. Further transformations produced more structural diversity and may inspire new ideas for developing functional molecules.
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Affiliation(s)
- Shiqi Jia
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, Henan, P. R. China
| | - Yuhong Tian
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, Chemical Biology Research Center, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, P. R. China
| | - Xin Li
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, Chemical Biology Research Center, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, P. R. China
| | - Pengfei Wang
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, Chemical Biology Research Center, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, P. R. China
| | - Yu Lan
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, Henan, P. R. China.,School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 401331, P. R. China
| | - Hailong Yan
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, Chemical Biology Research Center, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, P. R. China
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6
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Zhang XY, Tong Y, Li G, Zhao H, Chen G, Yao H, Tong R. 1,5‐Allyl Shift by a Sequential Achmatowicz/Oxonia‐Cope/Retro‐Achmatowicz Rearrangement. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202205919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Xiayan Y. Zhang
- Department of Chemistry The Hong Kong University of Science and Technology Clearwater Bay, Kowloon, Hong Kong China
- Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) The Hong Kong University of Science and Technology Clearwater Bay, Kowloon, Hong Kong China
| | - Yi Tong
- Department of Chemistry The Hong Kong University of Science and Technology Clearwater Bay, Kowloon, Hong Kong China
| | - Gang Li
- 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, 510260 China
| | - Hao Zhao
- 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, 510260 China
| | - Guanye Chen
- 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, 510260 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, 510260 China
| | - Rongbiao Tong
- Department of Chemistry The Hong Kong University of Science and Technology Clearwater Bay, Kowloon, Hong Kong China
- Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) The Hong Kong University of Science and Technology Clearwater Bay, Kowloon, Hong Kong 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, 510260 China
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7
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Jia S, Tian Y, Li X, Wang P, Lan Y, Yan H. Atroposelective Construction of Nine‐Membered Carbonate Bridged Biaryls. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202206501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Shiqi Jia
- Zhengzhou University Green Catalysis Center 重庆大学虎溪校区药学院 zhengzhou CHINA
| | - Yuhong Tian
- Chongqing University School of Pharmaceutical Sciences Chongqing CHINA
| | - Xin Li
- Chongqing University School of Pharmaceutical Sciences CHINA
| | - Pengfei Wang
- Chongqing University School of Pharmaceutical Sciences CHINA
| | - Yu Lan
- Chongqing University School of Chemistry and Chemical Engineering CHINA
| | - Hailong Yan
- Chongqing University Innovative Drug Research Center No.55 Daxuecheng South Rd 401331 Chongqing CHINA
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8
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Gao Y, Mao Y, Miao Z. Enantioselective 1,3-Dipolar (5+3) Cycloadditions of Oxidopyrylium Ylides and Vinylcyclopropanes toward 9-Oxabicyclononanes. Org Lett 2022; 24:3064-3068. [PMID: 35420826 DOI: 10.1021/acs.orglett.2c01037] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have developed an efficient and mild enantioselective palladium-catalyzed (5+3) cycloaddition of vinylcyclopropanes and oxidopyrylium ylides generated in situ from benzopyranones, in the presence of a chiral PHOX ligand. These reactions afford various highly functionalized bridged oxa-[3.3.1]carbocycles with three stereogenic centers that are challenging to synthesize, in moderate to good yields and enantioselectivities.
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Affiliation(s)
- Yanfeng Gao
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Weijin Road 94, Tianjin 300071, China
| | - Yuanhao Mao
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Weijin Road 94, Tianjin 300071, China
| | - Zhiwei Miao
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Weijin Road 94, Tianjin 300071, China.,Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300071, China
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9
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Li A, Gao Y, Lu JB, Chen ZC, Du W, Chen YC. Asymmetric higher-order [10+n] cycloadditions of palladium-containing 10π-cycloaddends. Chem Sci 2022; 13:9265-9270. [PMID: 36092999 PMCID: PMC9384823 DOI: 10.1039/d2sc02985e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 07/14/2022] [Indexed: 11/21/2022] Open
Abstract
We uncovered an asymmetric higher-order [10 + 2] cycloaddition reaction between diverse activated alkenes and a new type of π-allylpalladium complex-containing dipole-type 10π-cycloaddend, which was generated in situ from 2-methylene-1-indanols via a dehydrative insertion and deprotonation strategy under double activation of Pd(0) and phosphoric acid. A similar strategy was applied to an asymmetric higher-order [10 + 8] cycloaddition reaction or [10 + 4] cycloaddition reaction by using a heptafulvene derivative or a cyclic enone, respectively, as the acceptor. A variety of polycyclic frameworks imbedding an indene core were generally furnished in moderate to excellent yields with high levels of enantioselectivity by employing a newly designed chiral phosphoramidite ligand. A type of π-allylpalladium complex-containing 10π-cycloaddend generated from 2-methylene-1-indanols under double activation of Pd(0) and phosphoric acid undergoes asymmetric higher-order [10 + 2] cycloadditions with diverse activated alkenes.![]()
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Affiliation(s)
- Ao Li
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University Chengdu 610041 China +86 28 85502609
| | - Yang Gao
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University Chengdu 610041 China +86 28 85502609
| | - Jian-Bin Lu
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University Chengdu 610041 China +86 28 85502609
| | - Zhi-Chao Chen
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University Chengdu 610041 China +86 28 85502609
| | - Wei Du
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University Chengdu 610041 China +86 28 85502609
| | - Ying-Chun Chen
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University Chengdu 610041 China +86 28 85502609
- College of Pharmacy, Third Military Medical University Shapingba, Chongqing 400038 China
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10
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11
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Houk KN, Xue X, Liu F, Chen Y, Chen X, Jamieson C. Computations on Pericyclic Reactions Reveal the Richness of Ambimodal Transition States and Pericyclases. Isr J Chem 2021. [DOI: 10.1002/ijch.202100071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- K. N. Houk
- Department of Chemistry and Biochemistry University of California Los Angeles CA 90095-1569 USA
| | - Xiao‐Song Xue
- Department of Chemistry Nankai University Tianjin 300071 China
| | - Fang Liu
- College of Sciences Nanjing Agricultural University Nanjing Jiangsu 210095 China
| | - Yu Chen
- School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 China
| | - Xiangyang Chen
- Department of Chemistry and Biochemistry University of California Los Angeles CA 90095-1569 USA
| | - Cooper Jamieson
- Department of Chemistry and Biochemistry University of California Los Angeles CA 90095-1569 USA
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12
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Jessen NI, Bura M, Bertuzzi G, Jørgensen KA. Aminocatalytic [8+2] Cycloaddition Reactions toward Chiral Cyclazines. Angew Chem Int Ed Engl 2021; 60:18527-18531. [PMID: 34101936 DOI: 10.1002/anie.202106287] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Indexed: 01/18/2023]
Abstract
An efficient and exceptionally stereoselective synthesis of chiral cycl[3.2.2]azines has been realized by means of the rational design and utilization of novel (E)-3-benzylidene-3H-pyrrolizines in iminium-ion-catalyzed [8+2] cycloaddition reactions. The presented protocol allows for the incorporation of diverse enals, including cinnamaldehydes, enolizable aldehydes, and substrates of extended conjugation. The obtained products contain both an electron-rich alkenyl pyrrole moiety and an electron-deficient carbaldehyde substituent, and both moieties can undergo selective transformations with retention of the stereochemical information established in the [8+2] cycloaddition.
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Affiliation(s)
| | - Maksimilian Bura
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark
| | - Giulio Bertuzzi
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark
| | - Karl Anker Jørgensen
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark
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13
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Jessen NI, Bura M, Bertuzzi G, Jørgensen KA. Aminocatalytic [8+2] Cycloaddition Reactions toward Chiral Cyclazines. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202106287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Maksimilian Bura
- Department of Chemistry Aarhus University Langelandsgade 140 8000 Aarhus C Denmark
| | - Giulio Bertuzzi
- Department of Chemistry Aarhus University Langelandsgade 140 8000 Aarhus C Denmark
| | - Karl Anker Jørgensen
- Department of Chemistry Aarhus University Langelandsgade 140 8000 Aarhus C Denmark
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14
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Zhang Z, Han H, Wang L, Bu Z, Xie Y, Wang Q. Construction of bridged polycycles through dearomatization strategies. Org Biomol Chem 2021; 19:3960-3982. [PMID: 33978039 DOI: 10.1039/d1ob00096a] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Bridged polycycles are privileged molecular skeletons with wide occurrence in bioactive natural products and pharmaceuticals. Therefore, they have been the pursing target molecules of numerous chemists. The rapid and convenient generation of sp3-rich complex three-dimensional molecular skeletons from simple and easily available aromatics has made dearomatization a highly valuable synthetic tool for the construction of rigid and challenging bridged rings. This review summarizes the-state-of-the-art advances of dearomatization strategies in the application of bridged ring formation, discusses their advantages and limitations and the in-depth mechanism, and highlights their synthetic value in the total synthesis of natural products. We wish this review will provide an important reference for medicinal and synthetic chemists and will inspire further development in this intriguing research area.
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Affiliation(s)
- Ziying Zhang
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China.
| | - Huabin Han
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China.
| | - Lele Wang
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China.
| | - Zhanwei Bu
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China.
| | - Yan Xie
- College of Chemistry and Materials Engineering, Quzhou University, Quzhou 324000, China.
| | - Qilin Wang
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China.
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15
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Li L, Turnbull WL, McDonald R, West FG. Lithium Hydroxide Assisted
Endo
‐Selective [4+4]‐Photocycloaddition of Pyran‐2‐ones. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Lei Li
- Department of Chemistry University of Alberta E3-43 Gunning-Lemieux Chemistry Centre Edmonton AB T6G 2G2 Canada
| | - William L. Turnbull
- Department of Chemistry University of Alberta E3-43 Gunning-Lemieux Chemistry Centre Edmonton AB T6G 2G2 Canada
| | - Robert McDonald
- X-Ray Crystallography Laboratory Department of Chemistry University of Alberta E3-43 Gunning-Lemieux Chemistry Centre Edmonton AB T6G 2G2 Canada
| | - F. G. West
- Department of Chemistry University of Alberta E3-43 Gunning-Lemieux Chemistry Centre Edmonton AB T6G 2G2 Canada
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16
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Chen X, Thøgersen MK, Yang L, Lauridsen RF, Xue XS, Jørgensen KA, Houk KN. [8+2] vs [4+2] Cycloadditions of Cyclohexadienamines to Tropone and Heptafulvenes-Mechanisms and Selectivities. J Am Chem Soc 2021; 143:934-944. [PMID: 33416311 DOI: 10.1021/jacs.0c10966] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The cinchona-alkaloid-catalyzed cycloaddition reactions of 2-cyclohexenone with tropone and various heptafulvenes give [8+2] or [4+2] cycloadducts, depending on the substituents present on the heptafulvene. We report the results of new experiments with heptafulvenes, containing diester and barbiturate substituents, which in combination with computational studies were performed to elucidate the factors controlling [8+2] vs [4+2] cycloaddition pathways, including chemo-, regio-, and stereoselectivities of these higher-order cycloadditions. The protonated cinchona alkaloid primary amine catalyst reacts with 2-cyclohexenone to form a linear dienamine intermediate that subsequently undergoes a stepwise [8+2] or [4+2] cycloaddition. Both tropone and the different heptafulvenes initially form [8+2] cycloadducts. The final product is ultimately decided by the reversibility of the [8+2] cycloaddition and the relative thermal stability of the [4+2] products. The stereoisomeric transition states are distinguished by the steric interactions between the protonated catalyst and tropone/heptafulvenes. The [8+2] cycloaddition of barbiturate-heptafulvene afforded products with an unprecedented trans-fusion of the five- and six-membered rings, while the [8+2] cycloadducts obtained from cyanoester-heptafulvene and diester-heptafulvene were formed with a cis-relationship. The mechanism, thermodynamics, and origins of stereoselectivity were explained through DFT calculations using the ωB97X-D density functional.
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Affiliation(s)
- Xiangyang Chen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | | | - Limin Yang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States.,College of Materials, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 311121, China
| | - Rune F Lauridsen
- Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Xiao-Song Xue
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States.,State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | | | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
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17
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Bertuzzi G, McLeod D, Mohr LM, Jørgensen KA. Organocatalytic Enantioselective 1,3-Dipolar [6+4] Cycloadditions of Tropone. Chemistry 2020; 26:15491-15496. [PMID: 32677710 DOI: 10.1002/chem.202003329] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Indexed: 01/03/2023]
Abstract
A highly stereoselective 1,3-dipolar [6+4] cycloaddition towards bridged azabicyclo[4.3.1]decane scaffolds has been developed, reacting aldehydes, 2-aminomalonates and tropone under mild conditions in the presence of a chiral phosphoric acid catalyst. The scope is demonstrated for a series of aldehydes and 2-aminomalonates, and the reaction proceeds in high yields, >95:5 d.r. and up to 99 % ee. A series of transformations, as well as a mechanistic proposal, are presented.
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Affiliation(s)
- Giulio Bertuzzi
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark
| | - David McLeod
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark
| | - Lisa-Marie Mohr
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark
| | - Karl Anker Jørgensen
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark
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