1
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Ippoliti FM, Wonilowicz LG, Adamson NJ, Darzi ER, Donaldson JS, Nasrallah DJ, Mehta MM, Kelleghan AV, Houk KN, Garg NK. Total Synthesis of Lissodendoric Acid A. Angew Chem Int Ed Engl 2024; 63:e202406676. [PMID: 38695853 PMCID: PMC11461081 DOI: 10.1002/anie.202406676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Indexed: 07/04/2024]
Abstract
We describe a full account of our synthetic strategy leading to the first total synthesis of the manzamine alkaloid lissodendoric acid A . These efforts demonstrate that strained cyclic allenes are valuable synthetic building blocks and can be employed efficiently in total synthesis.
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Affiliation(s)
- Francesca M Ippoliti
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Chemistry, Hamline University, St. Paul, Minnesota, 55104, USA
| | - Laura G Wonilowicz
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Nathan J Adamson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Discovery Chemistry, Genentech, Inc., South San Francisco, CA 94080, USA
| | - Evan R Darzi
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
- ElectraTect, Inc., Phoenix, AZ 85004, USA
| | - Joyann S Donaldson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Pfizer Oncology Medicinal Chemistry, San Diego, CA 92121, USA
| | - Daniel J Nasrallah
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Chemistry, Roanoke College, Salem, Virginia, 24153, USA
| | - Milauni M Mehta
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Small Molecule Therapeutic Discovery, Amgen Research, Amgen Inc., Thousand Oaks, CA 91320, USA
| | - Andrew V Kelleghan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Gilead Sciences Medicinal Chemistry, Foster City, CA 94404, USA
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Neil K Garg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
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2
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Wonilowicz LG, Mehta MM, Kamecke L, French SA, Garg NK. Diels-Alder Cycloadditions of Oxacyclic Allenes and α-Pyrones. Org Lett 2024; 26:6465-6470. [PMID: 39046907 PMCID: PMC11459240 DOI: 10.1021/acs.orglett.4c02294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
Reactions of α-pyrones with oxacyclic allenes in Diels-Alder trappings are described. We investigate regioselectivity trends and perform competition experiments to assess the influence of structural and electronic features on relative reaction rates. We also demonstrate the stereospecific trapping of an oxacyclic allene, which proceeds in high optical yield. This study provides insight into strained cyclic allene reactivity, as well as new synthetic tools for the rapid construction of complex, heterocyclic scaffolds.
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Affiliation(s)
| | | | - Lisa Kamecke
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Sarah A. French
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Neil K. Garg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
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3
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McVeigh MS, Sorrentino JP, Hands AT, Garg NK. Access to Complex Scaffolds Through [2 + 2] Cycloadditions of Strained Cyclic Allenes. J Am Chem Soc 2024; 146:15420-15427. [PMID: 38768558 PMCID: PMC11459239 DOI: 10.1021/jacs.4c03369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
We report the strain-induced [2 + 2] cycloadditions of cyclic allenes for the assembly of highly substituted cyclobutanes. By judicious choice of trapping agent, complex scaffolds bearing heteroatoms, fused rings, contiguous stereocenters, spirocycles, and quaternary centers are ultimately accessible. Moreover, we show that the resulting cycloadducts can undergo thermal isomerization. This study provides an alternative strategy to photochemical [2 + 2] cycloadditions for accessing highly functionalized cyclobutanes, while validating the use of underexplored strained intermediates for the assembly of complex architectures.
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Affiliation(s)
- Matthew S McVeigh
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Jacob P Sorrentino
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Allison T Hands
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Neil K Garg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
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4
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Xu Q, Hoye TR. A Cascade of Strain-Driven Events Converting Benzynes to Alkynylbenzocyclobutenes to 1,3-Dien-5-ynes to Cyclic Allenes to Benzocyclohexadienones. J Am Chem Soc 2024; 146:6438-6443. [PMID: 38437506 DOI: 10.1021/jacs.3c10225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2024]
Abstract
Here, we report a strain-promoted cascade reaction that proceeds via multiple strained intermediates, ultimately driven by the high potential energy inherent in alkyne triple bonds (C≡C). More specifically, four alkynes (three from an HDDA benzyne precursor and the fourth from a conjugated enyne reaction partner) are transformed into eight of the skeletal carbons in the benzocyclohexadienone products. The reaction pathway proceeds sequentially via strained benzyne, benzocyclobutene, and cyclic allene intermediates. DFT computations suggest that the slowest step following benzyne generation is the 4π-electrocyclic ring-opening of the alkynylbenzocyclobutene to a 1,3-dien-5-yne (an alkynylxylylene) intermediate. The activation energy for the subsequent 6π-electrocyclic ring-closure is lower than that for related acyclic dienynes because of the aromaticity that is being regained in the transition structure. Finally, the isolation of the benzocyclohexadienone products rather than their phenolic tautomers is notable.
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Affiliation(s)
- Qian Xu
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, United States
| | - Thomas R Hoye
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, United States
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5
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Jankovic CL, McIntosh KC, Lofstrand VA, West FG. Stereoselective Intramolecular [2+2] Trapping of 1,2-Cyclohexadienes: a Route to Rigid, Angularly Fused Tricyclic Scaffolds. Chemistry 2023; 29:e202301668. [PMID: 37352092 DOI: 10.1002/chem.202301668] [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: 06/15/2023] [Revised: 06/22/2023] [Accepted: 06/23/2023] [Indexed: 06/25/2023]
Abstract
1,2-Cyclohexadienes generated under mild fluoride-mediated desilylative conditions undergo efficient intramolecular [2+2] trapping, providing tricyclic alkylidene cyclobutanes with complete diastereoselectivity for the cis-fused products. Pendent styrenes or electron-deficient olefins can trap simple 1,2-cyclohexadienes or their oxygenated counterparts, with 14 substrates being disclosed. Reactions proceed at ambient temperature using just cesium fluoride in up to 91 % yield, and the necessary precursors are easily accessed from substituted 2-bromocyclohexenones. Multiple synthetic routes have been developed to install the appropriate functional groups required for [2+2] trapping.
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Affiliation(s)
| | - Kyle C McIntosh
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - Verner A Lofstrand
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - F G West
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
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6
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Mehta MM, Gonzalez JAM, Bachman JL, Garg NK. Cyclic Allene Approach to the Manzamine Alkaloid Keramaphidin B. Org Lett 2023; 25:5553-5557. [PMID: 37387644 PMCID: PMC10460088 DOI: 10.1021/acs.orglett.3c01489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
We report an approach to the core of the manzamine alkaloid keramaphidin B that relies on the strain-promoted cycloaddition of an azacyclic allene with a pyrone trapping partner. The cycloaddition is tolerant of nitrile and primary amide functional groups and can be complemented with a subsequent retro-Diels-Alder step. These efforts demonstrate that strained cyclic allenes can be used to build significant structural complexity and should encourage further studies of these fleeting intermediates.
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Affiliation(s)
- Milauni M Mehta
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Jordan A M Gonzalez
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - James L Bachman
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Neil K Garg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
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7
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Witkowski DC, McVeigh MS, Scherer GM, Anthony SM, Garg NK. Catalyst-Controlled Annulations of Strained Cyclic Allenes with π-Allylpalladium Complexes. J Am Chem Soc 2023; 145:10491-10496. [PMID: 37141000 PMCID: PMC10460090 DOI: 10.1021/jacs.3c03102] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Strained cyclic allenes are a class of in situ-generated fleeting intermediates that, despite being discovered more than 50 years ago, has received significantly less attention from the synthetic community compared to related strained intermediates. Examples of trapping strained cyclic allenes that involve transition metal catalysis are especially rare. We report the first annulations of highly reactive cyclic allenes with in situ-generated π-allylpalladium species. By varying the ligand employed, either of two isomeric polycyclic scaffolds can be obtained with high selectivity. The products are heterocyclic and sp3-rich and bear two or three new stereocenters. This study should encourage the further development of fragment couplings that rely on transition metal catalysis and strained cyclic allenes for the rapid assembly of complex scaffolds.
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Affiliation(s)
- Dominick C Witkowski
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Matthew S McVeigh
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Georgia M Scherer
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Sarah M Anthony
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Neil K Garg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
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8
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Xu Q, Hoye TR. A Distinct Mode of Strain-Driven Cyclic Allene Reactivity: Group Migration to the Central Allene Carbon Atom. J Am Chem Soc 2023; 145:9867-9875. [PMID: 37086185 PMCID: PMC10864128 DOI: 10.1021/jacs.3c02469] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
Abstract
Strained cyclic allenes are reactive species that can be trapped in a variety of complementary fashions that capitalize on their inherent high potential energy. 1,2,4-Cyclohexatrienes represent a subclass of allenes that, notably, can be conveniently generated by a net [4 + 2] cycloaddition within a 1,3-enyne bearing a tethered alkyne via a tetradehydro-Diels-Alder reaction. A limitation to the use of this type of thermally generated cyclic allene as a construct for the introduction of molecular complexity is their propensity to isomerize to benzenoids via a simple net 1,5-hydrogen atom migration. We have discovered that when the enyne component of the substrate is modified as an enol silyl ether (or an enol ester), migration of the silyl (or acyl) group can become the predominant event. Specifically, an appropriately electrophilic group can migrate from the O atom to the central allene carbon adjacent to the 1-siloxy(acyloxy) substituent. This process leads to highly substituted phenolic products (e.g., o-silyl phenols) following tautomerization of the intermediate cyclohexa-2,4-dienone. Experimental studies show that this novel mode of reactivity is general; DFT studies reveal the unimolecular nature of the group migration.
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Affiliation(s)
- Qian Xu
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455, United States
| | - Thomas R. Hoye
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455, United States
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9
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Ippoliti FM, Adamson NJ, Wonilowicz LG, Nasrallah DJ, Darzi ER, Donaldson JS, Garg NK. Total synthesis of lissodendoric acid A via stereospecific trapping of a strained cyclic allene. Science 2023; 379:261-265. [PMID: 36656952 PMCID: PMC10462259 DOI: 10.1126/science.ade0032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 11/18/2022] [Indexed: 01/21/2023]
Abstract
Small rings that contain allenes are unconventional transient compounds that have been known since the 1960s. Despite being discovered around the same time as benzyne and offering a number of synthetically advantageous features, strained cyclic allenes have seen relatively little use in chemical synthesis. We report a concise total synthesis of the manzamine alkaloid lissodendoric acid A, which hinges on the development of a regioselective, diastereoselective, and stereospecific trapping of a fleeting cyclic allene intermediate. This key step swiftly assembles the azadecalin framework of the natural product, allows for a succinct synthetic endgame, and enables a 12-step total synthesis (longest linear sequence; 0.8% overall yield). These studies demonstrate that strained cyclic allenes are versatile building blocks in chemical synthesis.
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Affiliation(s)
| | | | - Laura G. Wonilowicz
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Daniel J. Nasrallah
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | | | | | - Neil K. Garg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
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10
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Jankovic CL, West FG. 2 + 2 Trapping of Acyloxy-1,2-cyclohexadienes with Styrenes and Electron-Deficient Olefins. Org Lett 2022; 24:9497-9501. [PMID: 36519787 DOI: 10.1021/acs.orglett.2c03978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Oxygenated-1,2-cyclohexadienes and their unsubstituted counterpart can be generated under mild conditions by fluoride-induced desilylation and undergo intermolecular [2 + 2]-cycloaddition reactions with a variety of alkene traps to afford bicyclo[4.2.0]octenes. Both styrenes and electron-deficient olefins react in good conversion and with complete regioselectivity in favor of cyclobutane formation at the unsubstituted C2/C3 carbons of the C1-substituted cyclic allenes. Diastereoselectivities are modest (1.1-5.7:1) with a preference for the exo-isomer.
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Affiliation(s)
- Christian L Jankovic
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - F G West
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
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11
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Abstract
Strained intermediates such as cyclic alkynes and allenes are most commonly utilized in nucleophilic additions and cycloadditions, but have seen increased use in a third area of reactivity: metal-mediated transformations. The merger of strained intermediates and metal catalysis has enabled rapid access to complex, polycyclic systems. Following a discussion of relevant landmark studies involving metals and strained intermediates, this article highlights recent advances in transition metal-mediated transformations from our laboratory. Specifically, this includes the use of arynes in the synthesis of decorated organometallic complexes, and the utilization of cyclic allenes to access enantioenriched heterocycles. Moreover, the broad applicability of such transformations, and exciting future areas of research are discussed.
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Affiliation(s)
- Katie A. Spence
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
- These authors contributed equally: Katie A. Spence and Arismel Tena Meza
| | - Arismel Tena Meza
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
- These authors contributed equally: Katie A. Spence and Arismel Tena Meza
| | - Neil K. Garg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
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12
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Abstract
AbstractFor a long time, allenes—and cumulenic systems in general—played a relatively minor role in Diels–Alder cycloadditions. This situation has changed, since allenes are more readily available and as their unique stereochemical features in [4+2]cycloadditions are more widely recognized. This review presents a comprehensive overview of allenes in Diels–Alder processes using selected examples. Allenes in dienes, dienophiles and cycloadducts are covered, inter- and intramolecular Diels–Alder cycloadditions are discussed, and stereochemical features of the addition process are described. Areas of emerging importance are also covered, including allenic components in dehydro-Diels–Alder processes, and dendralenic allenes in Diels–Alder sequences for the rapid generation of target-relevant molecular complexity. Preparatively useful methods for allenic precursor synthesis are also discussed.1 Introduction2 Allenic Dienes2.1 Vinylallenes2.2 Bisallenes2.3 Cross-conjugated Allenes3 Allenic Dienophiles4 Intramolecular Diels–Alder Cycloadditions5 Allenic Cycloadducts6 Conclusions and Outlook
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Affiliation(s)
- Henning Hopf
- Institut für Organische Chemie, Technische Universität Braunschweig
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13
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Abstract
Transient strained cyclic intermediates, such as strained cyclic allenes, are useful building blocks for the synthesis of structurally and stereochemically complex scaffolds. Trappings of strained cyclic allenes are thought to occur primarily through either two or one electron processes. Regarding the latter, diradical intermediates have been invoked in (2 + 2) cycloadditions and (3 + 2) nitrone cycloadditions. The present study questions if a monoradical pathway could exist for strained cyclic allene reactivity, as examined in the reaction of 1,2-cyclohexadiene and TEMPO radical. Our findings suggest the viability of this monoradical pathway.
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Affiliation(s)
- Matthew S. McVeigh
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, United States
| | - Neil K. Garg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, United States
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14
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Anthony S, Wonilowicz LG, McVeigh MS, Garg NK. Leveraging Fleeting Strained Intermediates to Access Complex Scaffolds. JACS AU 2021; 1:897-912. [PMID: 34337603 PMCID: PMC8317162 DOI: 10.1021/jacsau.1c00214] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Indexed: 05/07/2023]
Abstract
Arynes, strained cyclic alkynes, and strained cyclic allenes were validated as plausible intermediates in the 1950s and 1960s. Despite initially being considered mere scientific curiosities, these transient and highly reactive species have now become valuable synthetic building blocks. This Perspective highlights recent advances in the field that have allowed access to structural and stereochemical complexity, including recent breakthroughs in asymmetric catalysis.
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15
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Kelleghan AV, Witkowski DC, McVeigh MS, Garg NK. Palladium-Catalyzed Annulations of Strained Cyclic Allenes. J Am Chem Soc 2021; 143:9338-9342. [PMID: 34143634 PMCID: PMC8290222 DOI: 10.1021/jacs.1c04896] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report Pd-catalyzed annulations of in situ generated strained cyclic allenes. This methodology employs aryl halides and cyclic allene precursors as the reaction partners in order to generate fused heterocyclic products. The annulation proceeds via the formation of two new bonds and an sp3 center. Moreover, both diastereo- and enantioselective variants of this methodology are validated, with the latter ultimately enabling the rapid enantioselective synthesis of a complex hexacyclic product. Studies leveraging transition metal catalysis to intercept cyclic allenes represent a departure from the more common, historical modes of cyclic allene trapping that rely on nucleophiles or cycloaddition partners. As such, this study is expected to fuel the development of reactions that strategically merge transition metal catalysis and transient strained intermediate chemistry for the synthesis of complex scaffolds.
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Affiliation(s)
- Andrew V Kelleghan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Dominick C Witkowski
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Matthew S McVeigh
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Neil K Garg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
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16
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Zhang J, Xie Z. Tandem [4 + 2]/[2 + 2] cycloaddition of o-carboryne with enynes: facile construction of carborane-fused tricyclics. Chem Sci 2021; 12:5616-5620. [PMID: 34168796 PMCID: PMC8179614 DOI: 10.1039/d0sc07047e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 02/19/2021] [Indexed: 11/21/2022] Open
Abstract
o-Carboryne (1,2-dehydro-o-carborane) is a very useful synthon for the synthesis of a variety of carborane-functionalized molecules. With 1-Li-2-OTf-o-C2B10H10 as the precursor, o-carboryne undergoes an efficient [4 + 2] cycloaddition with various conjugated enynes, followed by a subsequent [2 + 2] cycloaddition at room temperature, generating a series of carborane-fused tricyclo[6.4.0.02,7]dodeca-2,12-dienes in moderate to high isolated yields. This reaction is compatible with many functional groups and has a broad substrate scope. A reactive carborane-fused 1,2-cyclohexadiene intermediate is involved, which is supported by experimental results and DFT calculations. This protocol offers a convenient strategy for the construction of complex carborane-functionalized tricyclics.
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Affiliation(s)
- Jie Zhang
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong Shatin, N. T. Hong Kong China
| | - Zuowei Xie
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong Shatin, N. T. Hong Kong China
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17
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Affiliation(s)
- Jiarong Shi
- School of Chemistry and Chemical Engineering, Chongqing University, 174 Shazheng Street, Chongqing, P. R. China, 400030
| | - Lianggui Li
- School of Chemistry and Chemical Engineering, Chongqing University, 174 Shazheng Street, Chongqing, P. R. China, 400030
| | - Yang Li
- School of Chemistry and Chemical Engineering, Chongqing University, 174 Shazheng Street, Chongqing, P. R. China, 400030
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18
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Wang B, Constantin MG, Singh S, Zhou Y, Davis RL, West FG. Generation and trapping of electron-deficient 1,2-cyclohexadienes. Unexpected hetero-Diels-Alder reactivity. Org Biomol Chem 2021; 19:399-405. [PMID: 33300539 DOI: 10.1039/d0ob02285c] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Keto-substituted 1,2-cyclohexadienes were generated by base-mediated (KOt-Bu) elimination, and found to dimerize via an unprecedented formal hetero-Diels-Alder process, followed by hydration. These highly reactive cyclic allene intermediates were also trapped in Diels-Alder reactions by furan, 2,5-dimethylfuran, or diphenylisobenzofuran to afford cycloadducts with high regio- and diastereoselectivity, and could also be intercepted in a hetero-Diels-Alder process with enamine dienophiles. Endo/exo stereochemistry was unambiguously determined via X-ray crystallography in the case of nitrile-substituted 1,2-cyclohexadiene. DFT calculations indicate that the novel hetero-Diels-Alder processes observed with these allenes occur via a concerted asynchronous cycloaddition mechanism.
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Affiliation(s)
- Baolei Wang
- Department of Chemistry, University of Alberta, E3-43 Gunning-Lemieux Chemistry Centre, Edmonton, AB, Canada T6G 2G2. and State-Key Laboratory of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Marius-Georgian Constantin
- Department of Chemistry, University of Alberta, E3-43 Gunning-Lemieux Chemistry Centre, Edmonton, AB, Canada T6G 2G2.
| | - Simarpreet Singh
- Department of Chemistry, University of Manitoba, 360 Parker Bldg., 144 Dysart Rd., Winnipeg, MN, Canada R3T 2N2
| | - Yuqiao Zhou
- Department of Chemistry, University of Alberta, E3-43 Gunning-Lemieux Chemistry Centre, Edmonton, AB, Canada T6G 2G2.
| | - Rebecca L Davis
- Department of Chemistry, University of Manitoba, 360 Parker Bldg., 144 Dysart Rd., Winnipeg, MN, Canada R3T 2N2
| | - F G West
- Department of Chemistry, University of Alberta, E3-43 Gunning-Lemieux Chemistry Centre, Edmonton, AB, Canada T6G 2G2.
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19
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Yu S, Vermeeren P, van Dommelen K, Bickelhaupt FM, Hamlin TA. Understanding the 1,3-Dipolar Cycloadditions of Allenes. Chemistry 2020; 26:11529-11539. [PMID: 32220086 PMCID: PMC7540365 DOI: 10.1002/chem.202000857] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/25/2020] [Indexed: 02/03/2023]
Abstract
We have quantum chemically studied the reactivity, site-, and regioselectivity of the 1,3-dipolar cycloaddition between methyl azide and various allenes, including the archetypal allene propadiene, heteroallenes, and cyclic allenes, by using density functional theory (DFT). The 1,3-dipolar cycloaddition reactivity of linear (hetero)allenes decreases as the number of heteroatoms in the allene increases, and formation of the 1,5-adduct is, in all cases, favored over the 1,4-adduct. Both effects find their origin in the strength of the primary orbital interactions. The cycloaddition reactivity of cyclic allenes was also investigated, and the increased predistortion of allenes, that results upon cyclization, leads to systematically lower activation barriers not due to the expected variations in the strain energy, but instead from the differences in the interaction energy. The geometric predistortion of cyclic allenes enhances the reactivity compared to linear allenes through a unique mechanism that involves a smaller HOMO-LUMO gap, which manifests as more stabilizing orbital interactions.
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Affiliation(s)
- Song Yu
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081 HVAmsterdamThe Netherlands
| | - Pascal Vermeeren
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081 HVAmsterdamThe Netherlands
| | - Kevin van Dommelen
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081 HVAmsterdamThe Netherlands
| | - F. Matthias Bickelhaupt
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081 HVAmsterdamThe Netherlands
- Institute for Molecules and Materials (IMM)Radboud UniversityHeyendaalseweg 1356525 AJNijmegenThe Netherlands
| | - Trevor A. Hamlin
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081 HVAmsterdamThe Netherlands
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20
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Intercepting fleeting cyclic allenes with asymmetric nickel catalysis. Nature 2020; 586:242-247. [PMID: 32846425 DOI: 10.1038/s41586-020-2701-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 08/12/2020] [Indexed: 12/21/2022]
Abstract
Strained cyclic organic molecules, such as arynes, cyclic alkynes and cyclic allenes, have intrigued chemists for more than a century with their unusual structures and high chemical reactivity1. The considerable ring strain (30-50 kilocalories per mole)2,3 that characterizes these transient intermediates imparts high reactivity in many reactions, including cycloadditions and nucleophilic trappings, often generating structurally complex products4. Although strategies to control absolute stereochemistry in these reactions have been reported using stoichiometric chiral reagents5,6, catalytic asymmetric variants to generate enantioenriched products have remained difficult to achieve. Here we report the interception of racemic cyclic allene intermediates in a catalytic asymmetric reaction and provide evidence for two distinct mechanisms that control absolute stereochemistry in such transformations: kinetic differentiation of allene enantiomers and desymmetrization of intermediate π-allylnickel complexes. Computational studies implicate a catalytic mechanism involving initial kinetic differentiation of the cyclic allene enantiomers through stereoselective olefin insertion, loss of the resultant stereochemical information, and subsequent introduction of absolute stereochemistry through desymmetrization of an intermediate π-allylnickel complex. These results reveal reactivity that is available to cyclic allenes beyond the traditional cycloadditions and nucleophilic trappings previously reported, thus expanding the types of product accessible from this class of intermediates. Additionally, our computational studies suggest two potential strategies for stereocontrol in reactions of cyclic allenes. Combined, these results lay the foundation for the development of catalytic asymmetric reactions involving these classically avoided strained intermediates.
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21
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Almehmadi YA, West FG. A Mild Method for the Generation and Interception of 1,2-Cycloheptadienes with 1,3-Dipoles. Org Lett 2020; 22:6091-6095. [PMID: 32790431 DOI: 10.1021/acs.orglett.0c02172] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
1,2-Cycloheptadiene is a strained, transient species that has been underutilized as a synthetic building block. Seven-membered cyclic allenes are mostly known for their propensity to undergo rapid dimerization, and relatively little has been reported regarding their cycloaddition reactivity with 1,3-dienes or 1,3-dipoles. This work describes the trapping of 1-acetoxy-1,2-cycloheptadiene and its unsubstituted counterpart, generated via desilylative elimination, with a range of 1,3-dipolar trapping partners, affording complex polycyclic products with high regio- and diastereoselectivity.
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Affiliation(s)
- Yaseen A Almehmadi
- Department of Chemistry, University of Alberta, W5-70D, Gunning/Lemieux Chemistry Centre, Edmonton, Alberta T6G 2G2, Canada.,Department of Chemistry, College of Science & Arts, King Abdulaziz University, P.O. Box 344, Rabigh 21911, Saudi Arabia
| | - F G West
- Department of Chemistry, University of Alberta, W5-70D, Gunning/Lemieux Chemistry Centre, Edmonton, Alberta T6G 2G2, Canada
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22
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McVeigh MS, Kelleghan AV, Yamano MM, Knapp RR, Garg NK. Silyl Tosylate Precursors to Cyclohexyne, 1,2-Cyclohexadiene, and 1,2-Cycloheptadiene. Org Lett 2020; 22:4500-4504. [PMID: 32437158 DOI: 10.1021/acs.orglett.0c01510] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Transient strained cyclic intermediates have become valuable intermediates in modern synthetic chemistry. Although silyl triflate precursors to strained intermediates are most often employed, the instability of some silyl triflates warrants the development of alternative precursors. We report the syntheses of silyl tosylate precursors to cyclohexyne, 1,2-cyclohexadiene, and 1,2-cycloheptadiene. The resultant strained intermediates undergo trapping in situ to give cycloaddition products. Additionally, the results of competition experiments between silyl triflates and silyl tosylates are reported.
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Affiliation(s)
- Matthew S McVeigh
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Andrew V Kelleghan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Michael M Yamano
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Rachel R Knapp
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Neil K Garg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
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23
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Gerry CJ, Schreiber SL. Recent achievements and current trajectories of diversity-oriented synthesis. Curr Opin Chem Biol 2020; 56:1-9. [DOI: 10.1016/j.cbpa.2019.08.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 08/21/2019] [Accepted: 08/26/2019] [Indexed: 12/14/2022]
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24
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Hioki Y, Mori A, Okano K. Steric effects on deprotonative generation of cyclohexynes and 1,2-cyclohexadienes from cyclohexenyl triflates by magnesium amides. Tetrahedron 2020. [DOI: 10.1016/j.tet.2020.131103] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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25
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Westphal MV, Hudson L, Mason JW, Pradeilles JA, Zécri FJ, Briner K, Schreiber SL. Water-Compatible Cycloadditions of Oligonucleotide-Conjugated Strained Allenes for DNA-Encoded Library Synthesis. J Am Chem Soc 2020; 142:7776-7782. [PMID: 32267148 DOI: 10.1021/jacs.9b13186] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
DNA-encoded libraries of small molecules are being explored extensively for the identification of binders in early drug-discovery efforts. Combinatorial syntheses of such libraries require water- and DNA-compatible reactions, and the paucity of these reactions currently limit the chemical features of resulting barcoded products. The present work introduces strain-promoted cycloadditions of cyclic allenes under mild conditions to DNA-encoded library synthesis. Owing to distinct cycloaddition modes of these reactive intermediates with activated olefins, 1,3-dipoles, and dienes, the process generates diverse molecular architectures from a single precursor. The resulting DNA-barcoded compounds exhibit unprecedented ring and topographic features, related to elements found to be powerful in phenotypic screening.
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Affiliation(s)
- Matthias V Westphal
- Chemical Biology and Therapeutics Science Program, Broad Institute, 415 Main Street, Cambridge, Massachusetts 02142, United States.,Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Liam Hudson
- Chemical Biology and Therapeutics Science Program, Broad Institute, 415 Main Street, Cambridge, Massachusetts 02142, United States.,Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Jeremy W Mason
- Chemical Biology and Therapeutics Science Program, Broad Institute, 415 Main Street, Cambridge, Massachusetts 02142, United States.,Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Johan A Pradeilles
- Chemical Biology and Therapeutics Science Program, Broad Institute, 415 Main Street, Cambridge, Massachusetts 02142, United States.,Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Frédéric J Zécri
- Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Karin Briner
- Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Stuart L Schreiber
- Chemical Biology and Therapeutics Science Program, Broad Institute, 415 Main Street, Cambridge, Massachusetts 02142, United States.,Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
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26
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Lofstrand VA, McIntosh KC, Almehmadi YA, West FG. Strain-Activated Diels-Alder Trapping of 1,2-Cyclohexadienes: Intramolecular Capture by Pendent Furans. Org Lett 2019; 21:6231-6234. [PMID: 31343882 DOI: 10.1021/acs.orglett.9b02085] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Intramolecular [4 + 2] cycloaddition reactions of substituted 1,2-cyclohexadienes with pendent furans enables the synthesis of complex tetracyclic scaffolds in a single step under mild conditions. All Diels-Alder cycloadducts were obtained as single diastereomers, assigned as the endo isomer. Substrates were easily assembled via Stork-Danheiser alkylation of 3-ethoxy-2-bromocyclohex-2-enone to accommodate a range of tethers and furan traps. Cleavage of enol acetate moieties resulted in room-temperature Diels-Alder cycloreversion to tethered furyl cyclohexenones.
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Affiliation(s)
- Verner A Lofstrand
- Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
| | - Kyle C McIntosh
- Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
| | - Yaseen A Almehmadi
- Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
| | - F G West
- Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
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27
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Yamano MM, Knapp RR, Ngamnithiporn A, Ramirez M, Houk KN, Stoltz BM, Garg NK. Cycloadditions of Oxacyclic Allenes and a Catalytic Asymmetric Entryway to Enantioenriched Cyclic Allenes. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201900503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Michael M. Yamano
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
| | - Rachel R. Knapp
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
| | - Aurapat Ngamnithiporn
- The Warren and Katharine Schlinger Laboratory of Chemistry and Chemical Engineering California Institute of Technology Pasadena CA 91125 USA
| | - Melissa Ramirez
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
| | - Kendall N. Houk
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
| | - Brian M. Stoltz
- The Warren and Katharine Schlinger Laboratory of Chemistry and Chemical Engineering California Institute of Technology Pasadena CA 91125 USA
| | - Neil K. Garg
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
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28
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Yamano MM, Knapp RR, Ngamnithiporn A, Ramirez M, Houk KN, Stoltz BM, Garg NK. Cycloadditions of Oxacyclic Allenes and a Catalytic Asymmetric Entryway to Enantioenriched Cyclic Allenes. Angew Chem Int Ed Engl 2019; 58:5653-5657. [PMID: 30811080 PMCID: PMC6456397 DOI: 10.1002/anie.201900503] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Indexed: 01/19/2023]
Abstract
The chemistry of strained cyclic alkynes has undergone a renaissance over the past two decades. However, a related species, strained cyclic allenes, especially heterocyclic derivatives, have only recently resurfaced and represent another class of valuable intermediates. We report a mild and facile means to generate the parent 3,4-oxacyclic allene from a readily accessible silyl triflate precursor, and then trap it in (4+2), (3+2), and (2+2) reactions to provide a variety of cycloadducts. In addition, we describe a catalytic, decarboxylative asymmetric allylic alkylation performed on an α-silylated substrate, to ultimately permit access to an enantioenriched allene. Generation and trapping of the enantioenriched cyclic allene occurs with complete transfer of stereochemical information in a Diels-Alder cycloaddition through a point-chirality, axial-chirality, point-chirality transfer process.
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Affiliation(s)
- Michael M Yamano
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Rachel R Knapp
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Aurapat Ngamnithiporn
- The Warren and Katharine Schlinger Laboratory of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Melissa Ramirez
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Kendall N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Brian M Stoltz
- The Warren and Katharine Schlinger Laboratory of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Neil K Garg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
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29
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Chari JV, Ippoliti FM, Garg NK. Concise Approach to Cyclohexyne and 1,2-Cyclohexadiene Precursors. J Org Chem 2019; 84:3652-3655. [PMID: 30840455 DOI: 10.1021/acs.joc.8b03223] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Silyl triflate precursors to cyclic alkynes and allenes serve as valuable synthetic building blocks. We report a concise and scalable synthetic approach to prepare the silyl triflate precursors to cyclohexyne and 1,2-cyclohexadiene. The strategy involves a retro-Brook rearrangement of an easily accessible cyclohexanone derivative, followed by triflation protocols. This simple, yet controlled, method should enable the further study of strained alkynes and allenes in chemical synthesis.
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Affiliation(s)
- Jason V Chari
- Department of Biochemistry and Chemistry , University of California , Los Angeles , California 90095 , United States
| | - Francesca M Ippoliti
- Department of Biochemistry and Chemistry , University of California , Los Angeles , California 90095 , United States
| | - Neil K Garg
- Department of Biochemistry and Chemistry , University of California , Los Angeles , California 90095 , United States
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30
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Barber JS, Yamano MM, Ramirez M, Darzi ER, Knapp RR, Liu F, Houk KN, Garg NK. Diels-Alder cycloadditions of strained azacyclic allenes. Nat Chem 2018; 10:953-960. [PMID: 30061614 DOI: 10.1038/s41557-018-0080-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 05/09/2018] [Indexed: 11/09/2022]
Abstract
For over a century, the structures and reactivities of strained organic compounds have captivated the chemical community. Whereas triple-bond-containing strained intermediates have been well studied, cyclic allenes have received far less attention. Additionally, studies of cyclic allenes that bear heteroatoms in the ring are scarce. We report an experimental and computational study of azacyclic allenes, which features syntheses of stable allene precursors, the mild generation and Diels-Alder trapping of the desired cyclic allenes, and explanations of the observed regio- and diastereoselectivities. Furthermore, we show that stereochemical information can be transferred from an enantioenriched silyl triflate starting material to a Diels-Alder cycloadduct by way of a stereochemically defined azacyclic allene intermediate. These studies demonstrate that heteroatom-containing cyclic allenes, despite previously being overlooked as valuable synthetic intermediates, may be harnessed for the construction of complex molecular scaffolds bearing multiple stereogenic centres.
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Affiliation(s)
- Joyann S Barber
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Michael M Yamano
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Melissa Ramirez
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Evan R Darzi
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Rachel R Knapp
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Fang Liu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA.
| | - Neil K Garg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA.
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31
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Inoue K, Nakura R, Okano K, Mori A. One-Pot Synthesis of Silylated Enol Triflates from Silyl Enol Ethers for Cyclohexynes and 1,2-Cyclohexadienes. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800353] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Kazuki Inoue
- Department of Chemical Science and Engineering; Kobe University; 1-1 Rokkodai 657-8501 Nada, Kobe Japan
| | - Ryo Nakura
- Department of Chemical Science and Engineering; Kobe University; 1-1 Rokkodai 657-8501 Nada, Kobe Japan
| | - Kentaro Okano
- Department of Chemical Science and Engineering; Kobe University; 1-1 Rokkodai 657-8501 Nada, Kobe Japan
| | - Atsunori Mori
- Department of Chemical Science and Engineering; Kobe University; 1-1 Rokkodai 657-8501 Nada, Kobe Japan
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32
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Hioki Y, Yukioka T, Okano K, Mori A. Deprotonative Generation of Cyclohexynes from Cyclic Enol Triflates Using Aluminate Bases. ASIAN J ORG CHEM 2018. [DOI: 10.1002/ajoc.201800205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Yuto Hioki
- Department of Chemical Science and Engineering; Kobe University; 1-1 Rokkodai Nada Kobe 657-8501 Japan
| | - Taro Yukioka
- Department of Chemical Science and Engineering; Kobe University; 1-1 Rokkodai Nada Kobe 657-8501 Japan
| | - Kentaro Okano
- Department of Chemical Science and Engineering; Kobe University; 1-1 Rokkodai Nada Kobe 657-8501 Japan
| | - Atsunori Mori
- Department of Chemical Science and Engineering; Kobe University; 1-1 Rokkodai Nada Kobe 657-8501 Japan
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33
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Domingo LR, Ríos-Gutiérrez M, Pérez P. A molecular electron density theory study of the [3 + 2] cycloaddition reaction of nitrones with strained allenes. RSC Adv 2017. [DOI: 10.1039/c7ra01916e] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The molecular electron density theory study of this [3 + 2] cycloaddition reveals that the strain present in the cyclic allene changes its reactivity to that characteristic of highly reactive radical species.
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Affiliation(s)
- Luis R. Domingo
- Department of Organic Chemistry
- University of Valencia
- E-46100 Burjassot
- Spain
| | - Mar Ríos-Gutiérrez
- Department of Organic Chemistry
- University of Valencia
- E-46100 Burjassot
- Spain
| | - Patricia Pérez
- Universidad Andres Bello
- Facultad de Ciencias Exactas
- Departamento de Ciencias Químicas
- Millennium Nucleus Chemical Processes and Catalysis (CPC)
- Santiago
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34
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Lofstrand VA, West FG. Efficient Trapping of 1,2-Cyclohexadienes with 1,3-Dipoles. Chemistry 2016; 22:10763-7. [PMID: 27219685 DOI: 10.1002/chem.201602201] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Indexed: 11/09/2022]
Abstract
1,2-Cyclohexadienes are transient intermediates that undergo rapid dimerization and intermolecular trapping with activated olefins and heteroatomic nucleophiles. Fluoride-mediated desilylative elimination of readily accessible 6-silylcyclohexene-1-triflates allows the mild, chemoselective, and functional-group tolerant generation of cyclic allene intermediates, which undergo efficient trapping reactions with stable 1,3-dipoles. The reactions proceed with high levels of both regio- and diastereoselectivity. The reaction of cyclic allenes with azides is accompanied by the facile loss of dinitrogen, resulting in the formation of tetrahydroindoles or polycylic aziridines depending on the azide employed.
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Affiliation(s)
- Verner A Lofstrand
- Department of Chemistry, University of Alberta, E3-43 Gunning-Lemieux Chemistry Centre, Edmonton, AB., T6G 2G2, Canada), Fax
| | - Frederick G West
- Department of Chemistry, University of Alberta, E3-43 Gunning-Lemieux Chemistry Centre, Edmonton, AB., T6G 2G2, Canada), Fax.
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35
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Sakashita K, Shibata Y, Tanaka K. Rhodium-Catalyzed Cross-Cyclotrimerization and Dimerization of Allenes with Alkynes. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201602155] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Kazuki Sakashita
- Department of Applied Chemistry, Graduate School of Science and Engineering; Tokyo Institute of Technology; O-okayama, Meguro-ku Tokyo 152-8550 Japan
- Department of Applied Chemistry, Graduate School of Engineering; Tokyo University of Agriculture and Technology; Koganei Tokyo 184-8588 Japan
| | - Yu Shibata
- Department of Applied Chemistry, Graduate School of Science and Engineering; Tokyo Institute of Technology; O-okayama, Meguro-ku Tokyo 152-8550 Japan
| | - Ken Tanaka
- Department of Applied Chemistry, Graduate School of Science and Engineering; Tokyo Institute of Technology; O-okayama, Meguro-ku Tokyo 152-8550 Japan
- Department of Applied Chemistry, Graduate School of Engineering; Tokyo University of Agriculture and Technology; Koganei Tokyo 184-8588 Japan
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36
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Sakashita K, Shibata Y, Tanaka K. Rhodium-Catalyzed Cross-Cyclotrimerization and Dimerization of Allenes with Alkynes. Angew Chem Int Ed Engl 2016; 55:6753-7. [PMID: 27110668 DOI: 10.1002/anie.201602155] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Indexed: 11/10/2022]
Abstract
It has been established that a cationic rhodium(I)/binap complex catalyzes the cross-cyclotrimerization of two molecules of a monosubstituted allene with one molecule of a functionalized alkyne to give 3,6-dialkylidenecyclohex-1-enes. In contrast, the reactions involving di- or trisubstituted allenes and/or unfunctionalized alkynes afforded cross-dimerization products, substituted dendralenes, through β-hydrogen elimination from the corresponding rhodacycles.
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Affiliation(s)
- Kazuki Sakashita
- Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, 152-8550, Japan.,Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, 184-8588, Japan
| | - Yu Shibata
- Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - Ken Tanaka
- Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, 152-8550, Japan. .,Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, 184-8588, Japan.
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37
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Barber JS, Styduhar ED, Pham HV, McMahon TC, Houk KN, Garg NK. Nitrone Cycloadditions of 1,2-Cyclohexadiene. J Am Chem Soc 2016; 138:2512-5. [PMID: 26854652 DOI: 10.1021/jacs.5b13304] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the first 1,3-dipolar cycloadditions of 1,2-cyclohexadiene, a rarely exploited strained allene. 1,2-Cyclohexadiene is generated in situ under mild conditions and trapped with nitrones to give isoxazolidine products in synthetically useful yields. The reactions occur regioselectively and exhibit a notable endo preference, thus resulting in the controlled formation of two new bonds and two stereogenic centers. DFT calculations of stepwise and concerted reaction pathways are used to rationalize the observed selectivities. Moreover, the strategic manipulation of nitrone cycloadducts demonstrates the utility of this methodology for the assembly of compounds bearing multiple heterocyclic units. These studies showcase the exploitation of a traditionally avoided reactive intermediate in chemical synthesis.
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Affiliation(s)
- Joyann S Barber
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Evan D Styduhar
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Hung V Pham
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Travis C McMahon
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Neil K Garg
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
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38
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Lledó A, Pla-Quintana A, Roglans A. Allenes, versatile unsaturated motifs in transition-metal-catalysed [2+2+2] cycloaddition reactions. Chem Soc Rev 2016; 45:2010-23. [DOI: 10.1039/c5cs00535c] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ThisTutorial Reviewhighlights the versatility of allenes as unsaturated substrates in transition-metal-catalysed [2+2+2] cycloaddition reactions in generating complex architectures.
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Affiliation(s)
- A. Lledó
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química
- Universitat de Girona (UdG)
- Facultat de Ciències
- 17071 Girona
- Spain
| | - A. Pla-Quintana
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química
- Universitat de Girona (UdG)
- Facultat de Ciències
- 17071 Girona
- Spain
| | - A. Roglans
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química
- Universitat de Girona (UdG)
- Facultat de Ciències
- 17071 Girona
- Spain
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39
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Zhao D, Zhang J, Xie Z. An Unprecedented Formal [5 + 2] Cycloaddition of Nitrones with o-Carboryne via Tandem [3 + 2] Cycloaddition/Oxygen Migration/Aromatization Sequence. J Am Chem Soc 2015; 137:13938-42. [DOI: 10.1021/jacs.5b09074] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Da Zhao
- Department of Chemistry and
State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong,
Shatin, N. T., Hong Kong, Hong Kong, China
| | - Jiji Zhang
- Department of Chemistry and
State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong,
Shatin, N. T., Hong Kong, Hong Kong, China
| | - Zuowei Xie
- Department of Chemistry and
State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong,
Shatin, N. T., Hong Kong, Hong Kong, China
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40
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Schurgers B, Brigou B, Urbanczyk-Lipkowska Z, Tourwé D, Ballet S, De Proft F, Van Lommen G, Verniest G. Synthesis of Fused 3-Aminoazepinones via Trapping of a New Class of Cyclic Seven-Membered Allenamides with Furan. Org Lett 2014; 16:3712-5. [DOI: 10.1021/ol501529z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
| | | | - Zofia Urbanczyk-Lipkowska
- Institute of Organic Chemistry, Polish Academy of
Sciences, Kasprzaka Str
44/52, 01-224 Warsaw, Poland
| | | | | | | | - Guy Van Lommen
- Department
of Medicinal Chemistry, Galapagos NV, Generaal De Wittelaan L11-A3 B-2800 Mechelen, Belgium
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41
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Affiliation(s)
- Annette D. Allen
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Thomas T. Tidwell
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
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42
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Peuronen A, Hänninen MM, Tuononen HM. Pyrazolium- and 1,2-Cyclopentadiene-Based Ligands as σ-Donors: a Theoretical Study of Electronic Structure and Bonding. Inorg Chem 2012; 51:2577-87. [DOI: 10.1021/ic202546a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Anssi Peuronen
- Department of Chemistry,
P.O. Box 35, University of Jyväskylä, FI-40014 Jyväskylä,
Finland
| | - Mikko M. Hänninen
- Department of Chemistry,
P.O. Box 35, University of Jyväskylä, FI-40014 Jyväskylä,
Finland
| | - Heikki M. Tuononen
- Department of Chemistry,
P.O. Box 35, University of Jyväskylä, FI-40014 Jyväskylä,
Finland
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43
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Sajna KV, Kotikalapudi R, Chakravarty M, Bhuvan Kumar NN, Swamy KCK. Cycloaddition Reactions of Allenylphosphonates and Related Allenes with Dialkyl Acetylenedicarboxylates, 1,3-Diphenylisobenzofuran, and Anthracene. J Org Chem 2011; 76:920-38. [DOI: 10.1021/jo102240u] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- K. V. Sajna
- School of Chemistry, University of Hyderabad, Hyderabad 500 046, A. P., India
| | - Ramesh Kotikalapudi
- School of Chemistry, University of Hyderabad, Hyderabad 500 046, A. P., India
| | - Manab Chakravarty
- School of Chemistry, University of Hyderabad, Hyderabad 500 046, A. P., India
| | - N. N. Bhuvan Kumar
- School of Chemistry, University of Hyderabad, Hyderabad 500 046, A. P., India
| | - K. C. Kumara Swamy
- School of Chemistry, University of Hyderabad, Hyderabad 500 046, A. P., India
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