1
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Tanaka K, Asada Y, Hoshino Y, Honda K. Visible-light-induced [4 + 2] cycloaddition of pentafulvenes by organic photoredox catalysis. Org Biomol Chem 2020; 18:8074-8078. [PMID: 32789391 DOI: 10.1039/d0ob01151g] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We have developed thioxanthylium photoredox catalyzed [4 + 2] cycloaddition of pentafulvenes at room temperature under green light irradiation, which affords tetrahydrocyclopenta[b]chromenes with high regioselectivities. The present reaction provides a sustainable approach to carry out the cycloaddition of pentafulvenes without the use of transition metal catalysts or high-temperature conditions. This procedure enables a mild and straightforward access to 1,3a,9,9a-tetrahydrocyclopenta[b]chromenes. The quantum yield of the reaction (Φ = 0.15) indicates that the reaction would mainly proceed via photocatalytic pathways.
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Affiliation(s)
- Kenta Tanaka
- Faculty of Pharmaceutical Science, Tokyo University of Science, 2641 Yamazaki, Noda-city, Chiba 278-8510, Japan.
| | - Yosuke Asada
- Graduate School of Environment and Information Sciences, Yokohama National University, Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan.
| | - Yujiro Hoshino
- Graduate School of Environment and Information Sciences, Yokohama National University, Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan.
| | - Kiyoshi Honda
- Graduate School of Environment and Information Sciences, Yokohama National University, Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan.
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2
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Swan E, Platts K, Blencowe A. An overview of the cycloaddition chemistry of fulvenes and emerging applications. Beilstein J Org Chem 2019; 15:2113-2132. [PMID: 31579091 PMCID: PMC6753682 DOI: 10.3762/bjoc.15.209] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 08/21/2019] [Indexed: 01/21/2023] Open
Abstract
The unusual electronic properties and unique reactivity of fulvenes have interested researchers for over a century. The propensity to form dipolar structures at relatively low temperatures and to participate as various components in cycloaddition reactions, often highly selectively, makes them ideal for the synthesis of complex polycyclic carbon scaffolds. As a result, fulvene cycloaddition chemistry has been employed extensively for the synthesis of natural products. More recently, fulvene cycloaddition chemistry has also found application to other areas including materials chemistry and dynamic combinatorial chemistry. This highlight article discusses the unusual properties of fulvenes and their varied cycloaddition chemistry, focussing on applications in organic and natural synthesis, dynamic combinatorial chemistry and materials chemistry, including dynamers, hydrogels and charge transfer complexes. Tables providing comprehensive directories of fulvene cycloaddition chemistry are provided, including fulvene intramolecular and intermolecular cycloadditions complete with reactant partners and their resulting cyclic adducts, which provide a useful reference source for synthetic chemists working with fulvenes and complex polycyclic scaffolds.
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Affiliation(s)
- Ellen Swan
- School of Pharmacy and Medical Sciences, The University of South Australia, Adelaide, South Australia 5000, Australia
| | - Kirsten Platts
- School of Pharmacy and Medical Sciences, The University of South Australia, Adelaide, South Australia 5000, Australia
| | - Anton Blencowe
- School of Pharmacy and Medical Sciences, The University of South Australia, Adelaide, South Australia 5000, Australia.,Future Industries Institute, The University of South Australia, Mawson Lakes, South Australia 5095, Australia
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3
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Eyilcim O, Issever S, Ocal N, Gronert S, Erden I. Imidazolidin-4-ones via (3+2) cycloadditions of aza-oxyallyl cations onto ( E)- Narylideneanilines. Tetrahedron Lett 2018; 59:3674-3677. [PMID: 30449908 DOI: 10.1016/j.tetlet.2018.08.056] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
In the course of our studies on the chemistry of oxyallyl species we uncovered a new (3+2) cycloaddition of aza-oxyallyl systems, generated in situ from N-benzyloxy-2-chloroamides in the presence of NEt3, onto N-arylimines yielding imidazolidin-4-ones in moderate to good yields. The cycloadditions are regioselective. Computational modelling using DFT at the M062×/6-311+G** level is in support the observed regioselectivities. Although the path to the trans imidazolin-4-one is favored, the cis product is preferred by almost 8 kcal/mol and could be formed by base-catalyzed epimerization. All products were isolated by chromatography and characterized by means of their FTIR, NMR and HRMS data.
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Affiliation(s)
- Oznur Eyilcim
- Department of Chemistry, Faculty of Arts and Sciences, Yildiz Technical University, Davutpasa Campus, 34220 Esenler-Istanbul, Turkey
| | - Sezin Issever
- Department of Chemistry, Faculty of Arts and Sciences, Yildiz Technical University, Davutpasa Campus, 34220 Esenler-Istanbul, Turkey
| | - Nuket Ocal
- Department of Chemistry, Faculty of Arts and Sciences, Yildiz Technical University, Davutpasa Campus, 34220 Esenler-Istanbul, Turkey
| | - Scott Gronert
- Department of Chemistry Virginia Commonwealth University, 1001 West Main Street, Richmond, Virginia 23284, USA
| | - Ihsan Erden
- Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Avenue, San Francisco, Ca 94132, USA
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4
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Christopher Braddock D, Mahtey A, Rzepa HS, White AJP. Stable bromoallene oxides. Chem Commun (Camb) 2016; 52:11219-11222. [PMID: 27722258 DOI: 10.1039/c6cc06395k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first stable bromoallene oxides were obtained by the DMDO epoxidation of 1-bromo-1,3-di-tert-alkylallenes, producing the first crystalline allene oxide of any kind. The epoxidations are regioselective for the bromine-bearing Δ1,2 alkene, and also face selective producing single diastereomer E-olefin products.
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Affiliation(s)
| | - Areeb Mahtey
- Department of Chemistry, Imperial College London, London, SW7 2AZ, UK.
| | - Henry S Rzepa
- Department of Chemistry, Imperial College London, London, SW7 2AZ, UK.
| | - Andrew J P White
- Department of Chemistry, Imperial College London, London, SW7 2AZ, UK.
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5
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Erden I, Basada J, Poli D, Cabrera G, Xu F, Gronert S. Unusual hydroxyl effect on fulvene endoperoxide decompositions. Tetrahedron Lett 2016; 57:2190-2193. [PMID: 27175039 PMCID: PMC4860729 DOI: 10.1016/j.tetlet.2016.04.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The thermal decomposition of fulvene endoperoxides ordinarily proceeds via an allene oxide intermediate affording oxepin-2(3H)-one derivatives. We have now uncovered new, unusual pathways in these decompositions where the presence of a hydroxyl group on the alkyl or aryl attached to the fulvene exocyclic double bond has a profound effect on the fate of the reactive intermediates derived from the unstable endoperoxides. Computational work supports the proposed mechanistic pathways.
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Affiliation(s)
- Ihsan Erden
- San Francisco State University, Department of Chemistry and Biochemistry, 1600 Holloway Avenue, San Francisco, CA 94132, USA
| | - John Basada
- San Francisco State University, Department of Chemistry and Biochemistry, 1600 Holloway Avenue, San Francisco, CA 94132, USA
| | - Daniela Poli
- San Francisco State University, Department of Chemistry and Biochemistry, 1600 Holloway Avenue, San Francisco, CA 94132, USA
| | - Gabriel Cabrera
- San Francisco State University, Department of Chemistry and Biochemistry, 1600 Holloway Avenue, San Francisco, CA 94132, USA
| | - Fupei Xu
- San Francisco State University, Department of Chemistry and Biochemistry, 1600 Holloway Avenue, San Francisco, CA 94132, USA
| | - Scott Gronert
- Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, Virginia 23284, USA
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6
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Erden I, Gronert S, Keeffe JR, Ma J, Ocal N, Gärtner C, Soukup LL. Effect of allylic groups on S(N)2 reactivity. J Org Chem 2014; 79:6410-8. [PMID: 24977317 PMCID: PMC4111211 DOI: 10.1021/jo501157s] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
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The activating effects of the benzyl
and allyl groups on SN2 reactivity are well-known. 6-Chloromethyl-6-methylfulvene,
also a primary, allylic halide, reacts 30 times faster with KI/acetone
than does benzyl chloride at room temperature. The latter result,
as well as new experimental observations, suggests that the fulvenyl
group is a particularly activating allylic group in SN2
reactions. Computational work on identity SN2 reactions,
e.g., chloride– displacing chloride– and ammonia displacing ammonia, shows that negatively charged SN2 transition states (tss) are activated by allylic groups
according to the Galabov–Allen–Wu electrostatic model
but with the fulvenyl group especially effective at helping to delocalize
negative charge due to some cyclopentadienide character in the transition
state (ts). In contrast, the triafulvenyl group is deactivating. However,
the positively charged SN2 transition states of the ammonia
reactions are dramatically stabilized by the triafulvenyl group, which
directly conjugates with a reaction center having SN1 character
in the ts. Experiments and calculations on the acidities of a variety
of allylic alcohols and carboxylic acids support the special nature
of the fulvenyl group in stabilizing nearby negative charge and highlight
the ability of fulvene species to dramatically alter the energetics
of processes even in the absence of direct conjugation.
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Affiliation(s)
- Ihsan Erden
- Department of Chemistry and Biochemistry, San Francisco State University , 1600 Holloway Avenue, San Francisco, California 94132, United States
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7
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Erden I, Ma J, Gärtner C, Azimi S, Gronert S. Temperature-dependent, competitive 1,3-acyl shift versus decarbonylation of a cyclopropanone intermediate. Tetrahedron 2013; 69:5044-5047. [PMID: 23956469 PMCID: PMC3744118 DOI: 10.1016/j.tet.2013.03.053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Photooxygenation of 1,1,3-trimethyl-1,2-dihydropentalene gives an unstable endoperoxide which upon decomposition delivers a bicyclic cyclopropanone intermediate; this species either extrudes CO to give a cycloheptadienone or undergoes a 1,3-acyl shift, both processes occurring most likely in a stepwise manner via diradical intermediates. Alternatively, C3a-C4 cleavage in the dioxygen diradical derived from the endoperoxide yields a 2-cyclopropyl substituted cyclopentadienone epoxide.
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Affiliation(s)
- Ihsan Erden
- Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132
| | - Jingxiang Ma
- Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132
| | - Christian Gärtner
- Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132
| | - Saeed Azimi
- Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132
| | - Scott Gronert
- Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, Virginia, 23284, Oliver Hall 3041
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8
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Gbur RK, Little RD. Unveiling the role of molecule-assisted homolysis: a mechanistic probe into the chemistry of a bicyclic peroxide. J Org Chem 2012; 77:2134-41. [PMID: 22356266 DOI: 10.1021/jo300297u] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Unlike the reaction of aryl-substituted diazenes, pyrolysis of alkyl-substituted diazenes in the presence of molecular oxygen generates an unexpectedly complex product mixture. Using deuterium labeling studies, in conjunction with quantum calculations, a reasonable mechanistic hypothesis for the decomposition of the resultant [3.3.0] peroxide, and subsequent formation of the keto-alcohol and Z-configured α,β-unsaturated keto-aldehyde, is proposed. Surprisingly, molecule-assisted homolysis plays a key role in this transformation, the details of which are discussed herein.
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Affiliation(s)
- Randi K Gbur
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, USA
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9
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Abstract
The effects of the nature and amount of base, substrate structure, amount of added water and solvent on the condensation of carbonyl compounds with cyclopentadiene in the presence of secondary amines were investigated. Based on these studies, a new efficient and green synthesis of fulvenes was developed.
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Affiliation(s)
- Necdet Coşkun
- On leave from Uludag University, Department of Chemistry, 16059, Bursa, Turkey
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10
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Coşkun N, Ma J, Azimi S, Gärtner C, Erden I. 1,2-Dihydropentalenes from fulvenes by [6 + 2] cycloadditions with 1-isopropenylpyrrolidine. Org Lett 2011; 13:5952-5. [PMID: 22029269 DOI: 10.1021/ol202222d] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In situ generated acetone pyrrolidine enamine undergoes [6 + 2] cycloadditions with fulvenes to give 1,2-dihydropentalenes. This ring annulation method works particularly well with 6-monosubstituted fulvenes and is subject to steric hindrance at C-6 of the fulvene. On the basis of mechanistic studies, optimal conditions have been developed for a one-pot synthesis of 1,2-dihydropentalenes using catalytic amounts of pyrrolidine.
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Affiliation(s)
- Necdet Coşkun
- Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Avenue, San Francisco, California 94132, United States
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11
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Erden I, Gärtner C. An exceptionally simple and efficient synthesis of 6-methyl-6-vinylfulvene, and its oxidative transformations. Tetrahedron Lett 2009; 50:2381-2383. [PMID: 20161263 PMCID: PMC2700951 DOI: 10.1016/j.tetlet.2009.02.221] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A new efficient synthesis of 6-methyl-6-vinylfulvene was developed, starting from the 6-(2-hydroxyethyl)-6-methylfulvene. With larger quantities of the title compound in hand, its photooxygenation with singlet oxygen was studied. Cyclization of the cyclopropanone intermediate to both vinyl moieties in the unsaturated system was observed, whereas the saturated endoperoxide gave mostly the cyclopentenone derivative. m-CPBA attacks exclusively the endocyclic double bonds and gives the 3-cyclopentenones via the unstable epoxides.
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Affiliation(s)
- Ihsan Erden
- San Francisco State University, Department of Chemistry and Biochemistry, 1600 Holloway Avenue, San Francisco, CA 94132, USA
| | - Christian Gärtner
- San Francisco State University, Department of Chemistry and Biochemistry, 1600 Holloway Avenue, San Francisco, CA 94132, USA
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12
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Erden I, Ocal N, Song J, Gleason C, Gärtner C. Unusual endoperoxide isomerizations: a convenient entry into 2-vinyl-2-cyclopentenones from saturated fulvene endoperoxides. Tetrahedron 2006; 62:10676-10682. [PMID: 17998948 DOI: 10.1016/j.tet.2006.07.107] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
An unusual peroxide base promoted isomerization was uncovered. Saturated endoperoxides derived from fulvenes give rise to 2-vinyl-2-cyclopentenones upon treatment with DBU in CH(2)Cl(2) in a one-pot reaction. This methodology was applied to a convenient synthesis of dihydrojasmone. Moreover, functional groups placed on the side chain at C-6 participate in the base catalyzed isomerizations via conjugate attack at the enone moiety to give 2-cyclopentenones carrying oxygen heterocycles at C2.
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Affiliation(s)
- Ihsan Erden
- San Francisco State University, Department of Chemistry, 1600 Holloway Avenue, San Francisco, CA 94132, USAYildiz Technical University, Faculty of Arts and Sciences, Department of Chemistry, Davutpasa Campus, 34010, Merter-Istanbul, Turkey
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13
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Breen LE, Schepp NP, Tan CHE. Photochemical generation and 1H NMR detection of alkyl allene oxides in solution. CAN J CHEM 2005. [DOI: 10.1139/v05-139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Irradiation of substituted 5-alkyl-4,5-epoxyvalerophenones leads to the formation of alkyl allene oxides that, in some cases, are sufficiently long-lived to be detected at room temperature by 1H NMR spectroscopy. Absolute lifetime measurements show that the size of the alkyl group has a significant influence on the reactivity of the allene oxide, with tert-butyl allene oxide having a lifetime of 24 h in CD3CN at room temperature that is considerably longer than the 1.5 h lifetime of the ethyl allene oxide. The allene oxides react rapidly with water to give α-hydroxyketones. The mechanism involves nucleophilic attack to the epoxide carbon to give an enol, which can also be detected as an intermediate by 1H NMR spectroscopy.Key words: allene oxides, mechanisms, absolute reactivity, kinetics, photochemistry.
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14
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Özer G, Saraçoǧlu N, Balci M. Unusual fragmentation of fulvene endoperoxides with phenyliodosyl bis(trifluoroacetate) (PIFA). J Heterocycl Chem 2003. [DOI: 10.1002/jhet.5570400319] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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15
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Erden I, Xu FP, Cao WG. Sigmatrope Verschiebungen bei Allenoxid-Umlagerungen: der erste allgemeine Zugang zu [3,4]-Verschiebungen in aliphatischen in Systemen. Angew Chem Int Ed Engl 1997. [DOI: 10.1002/ange.19971091330] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Konoike T, Hayashi T, Araki Y. (S)-(−)-2-tert-butyl-3-methylene-oxirane: Synthesis and hydroboration of a chiral allene oxide. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/0957-4166(94)80126-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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17
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Three-Membered Ring Systems. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/s0959-6380(13)70008-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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