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Bucher CB, Linden A, Heimgartner H. Synthesis and Solid State Conformation of Tetrapeptide Amides Containing two Aib and two (αMe)Phe Residues - Use of Enantiomerically Pure 2-Benzyl-2-methyl-2H-azirin-3-amines as (αMe)Phe-Synthons. Chem Biodivers 2020; 17:e2000246. [PMID: 32368841 DOI: 10.1002/cbdv.202000246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/05/2020] [Indexed: 01/15/2023]
Abstract
A series of tetrapeptide amides containing two aminoisobutyric acids (Aib) and two α-methylphenylalanine ((αMe)Phe) units were prepared through the 'azirine/oxazolone method'. New 2-benzyl-2-methyl-2H-azirin-3-amines have been used for the selective introduction of (S)- and (R)-(αMe)Phe, respectively. The solid-state conformations of five tetrapeptide amides were determined by X-ray crystallography. In all cases, two β-turns stabilize 310 -helical conformations and it was confirmed that, in contrast to proteinogenic amino acids, the configuration of (αMe)Phe does not determine the screw sense of the helix.
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Affiliation(s)
- Christoph B Bucher
- University of Zurich, 1996., Present address: Novartis Pharma AG, Lichtstrasse 35, CH-, 4056, Basel
| | - Anthony Linden
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-, 8057, Zurich
| | - Heinz Heimgartner
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-, 8057, Zurich
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2
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Okamoto K, Nanya A, Eguchi A, Ohe K. Asymmetric Synthesis of 2H
-Azirines with a Tetrasubstituted Stereocenter by Enantioselective Ring Contraction of Isoxazoles. Angew Chem Int Ed Engl 2017; 57:1039-1043. [DOI: 10.1002/anie.201710920] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Indexed: 12/14/2022]
Affiliation(s)
- Kazuhiro Okamoto
- Department of Energy and Hydrocarbon Chemistry; Graduate School of Engineering; Kyoto University; Katsura Nishikyo-ku Kyoto 615-8510 Japan
| | - Atsushi Nanya
- Department of Energy and Hydrocarbon Chemistry; Graduate School of Engineering; Kyoto University; Katsura Nishikyo-ku Kyoto 615-8510 Japan
| | - Akira Eguchi
- Department of Energy and Hydrocarbon Chemistry; Graduate School of Engineering; Kyoto University; Katsura Nishikyo-ku Kyoto 615-8510 Japan
| | - Kouichi Ohe
- Department of Energy and Hydrocarbon Chemistry; Graduate School of Engineering; Kyoto University; Katsura Nishikyo-ku Kyoto 615-8510 Japan
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3
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Okamoto K, Nanya A, Eguchi A, Ohe K. Asymmetric Synthesis of 2H
-Azirines with a Tetrasubstituted Stereocenter by Enantioselective Ring Contraction of Isoxazoles. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201710920] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Kazuhiro Okamoto
- Department of Energy and Hydrocarbon Chemistry; Graduate School of Engineering; Kyoto University; Katsura Nishikyo-ku Kyoto 615-8510 Japan
| | - Atsushi Nanya
- Department of Energy and Hydrocarbon Chemistry; Graduate School of Engineering; Kyoto University; Katsura Nishikyo-ku Kyoto 615-8510 Japan
| | - Akira Eguchi
- Department of Energy and Hydrocarbon Chemistry; Graduate School of Engineering; Kyoto University; Katsura Nishikyo-ku Kyoto 615-8510 Japan
| | - Kouichi Ohe
- Department of Energy and Hydrocarbon Chemistry; Graduate School of Engineering; Kyoto University; Katsura Nishikyo-ku Kyoto 615-8510 Japan
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4
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Koba Y, Ueda A, Oba M, Doi M, Demizu Y, Kurihara M, Tanaka M. Helical l
-Leu-Based Peptides Having Chiral Five-Membered Carbocyclic Ring Amino Acids with an Ethylene Acetal Moiety. ChemistrySelect 2017. [DOI: 10.1002/slct.201700832] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yurie Koba
- Graduate School of Biomedical Sciences; Nagasaki University, 1-14 Bunkyo-machi; Nagasaki 852-8521 Japan
| | - Atsushi Ueda
- Graduate School of Biomedical Sciences; Nagasaki University, 1-14 Bunkyo-machi; Nagasaki 852-8521 Japan
| | - Makoto Oba
- Graduate School of Biomedical Sciences; Nagasaki University, 1-14 Bunkyo-machi; Nagasaki 852-8521 Japan
| | - Mitsunobu Doi
- Osaka University of Pharmaceutical Sciences; Osaka 569-1094 Japan
| | - Yosuke Demizu
- Division of Organic Chemistry; National Institute of Health Sciences; Tokyo 158-8501 Japan
| | - Masaaki Kurihara
- Graduate School of Pharmaceutical Sciences; International University of Health and Welfare; Ohtawara 324-8501 Japan
| | - Masakazu Tanaka
- Graduate School of Biomedical Sciences; Nagasaki University, 1-14 Bunkyo-machi; Nagasaki 852-8521 Japan
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5
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Jin QW, Chai Z, Huang YM, Zou G, Zhao G. Asymmetric α-amination of 3-substituted oxindoles using chiral bifunctional phosphine catalysts. Beilstein J Org Chem 2016; 12:725-31. [PMID: 27340464 PMCID: PMC4902028 DOI: 10.3762/bjoc.12.72] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 04/05/2016] [Indexed: 11/23/2022] Open
Abstract
A highly enantioselective α-amination of 3-substituted oxindoles with azodicarboxylates catalyzed by amino acids-derived chiral phosphine catalysts is reported. The corresponding products containing a tetrasubstituted carbon center attached to a nitrogen atom at the C-3 position of the oxindole were obtained in high yields and with up to 98% ee.
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Affiliation(s)
- Qiao-Wen Jin
- Laboratory of Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, People’s Republic of China
| | - Zhuo Chai
- Key Laboratory of Synthetic Chemistry of Natural Substances, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, People’s Republic of China
| | - You-Ming Huang
- Key Laboratory of Synthetic Chemistry of Natural Substances, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, People’s Republic of China
| | - Gang Zou
- Laboratory of Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, People’s Republic of China
| | - Gang Zhao
- Key Laboratory of Synthetic Chemistry of Natural Substances, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, People’s Republic of China
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6
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He YT, Wang Q, Zhao J, Wang XZ, Qiu YF, Yang YC, Hu JY, Liu XY, Liang YM. Copper-Catalyzed Cascade Cyclization for the Synthesis of Trifluoromethyl-Substituted Spiro-2H-azirines from 1,6-Enynes. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201500510] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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7
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Yang Z, Wang Z, Bai S, Shen K, Chen D, Liu X, Lin L, Feng X. Highly enantioselective synthesis of 3-amino-2-oxindole derivatives: catalytic asymmetric alpha-amination of 3-substituted 2-oxindoles with a chiral scandium complex. Chemistry 2010; 16:6632-7. [PMID: 20408167 DOI: 10.1002/chem.201000126] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A highly enantioselective alpha-amination of 3-substituted oxindoles with azodicarboxylates catalyzed by a chiral Sc(OTf)(3)/N,N'-dioxide complex (Tf: triflate) has been developed and affords the corresponding 3-amino-2-oxindole derivatives in high yields (up to 98%) with excellent enantioselectivities (up to 99% ee). The procedure is capable of tolerating a relatively wide range of substrates, and excellent results (92-96% ee) can also be obtained, even in the presence of 0.5 mol % of catalyst loading under mild conditions. These results showed the potential value of the catalytic approach. Moreover, with high synthetic versatility, the product could be easily transformed into optically active 3-amino-3-methyloxindole bearing a chiral quaternary stereogenic center.
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Affiliation(s)
- Zhigang Yang
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, PR China
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8
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Fankel S, Helten H, von Frantzius G, Schnakenburg G, Daniels J, Chu V, Müller C, Streubel R. Novel access to azaphosphiridine complexes and first applications using Brønsted acid-induced ring expansion reactions. Dalton Trans 2010; 39:3472-81. [DOI: 10.1039/b922166b] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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9
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Uraguchi D, Asai Y, Ooi T. Site-Directed Asymmetric Quaternization of a Peptide Backbone at a C-Terminal Azlactone. Angew Chem Int Ed Engl 2009; 48:733-7. [DOI: 10.1002/anie.200803661] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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Uraguchi D, Asai Y, Ooi T. Site-Directed Asymmetric Quaternization of a Peptide Backbone at a C-Terminal Azlactone. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200803661] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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11
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Roedel JN, Lorenz IP. 2H-Azirines as Ligands: Structural Characterization of the First Neutral and Cationic (η5-C5Me5)Rh(III) 2H-Azirine Complexes. Z Anorg Allg Chem 2008. [DOI: 10.1002/zaac.200800098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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12
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Brun K, Linden A, Heimgartner H. Synthesis and Conformational Analysis of Pentapeptides Containing Enantiomerically Pure 2,2-Disubstituted Glycines. Helv Chim Acta 2008. [DOI: 10.1002/hlca.200890057] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Chinchilla R, Nájera C, Ortega FJ. Convenient Conditions for the Enantioselective Synthesis of α-Methyl-α-amino Acids with the Use ofCinchonaAmmonium Salts as Phase-Transfer Organocatalysts. European J Org Chem 2007. [DOI: 10.1002/ejoc.200700925] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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14
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Bräse S, Gil C, Knepper K, Zimmermann V. Organic azides: an exploding diversity of a unique class of compounds. Angew Chem Int Ed Engl 2006; 44:5188-240. [PMID: 16100733 DOI: 10.1002/anie.200400657] [Citation(s) in RCA: 1636] [Impact Index Per Article: 90.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Since the discovery of organic azides by Peter Griess more than 140 years ago, numerous syntheses of these energy-rich molecules have been developed. In more recent times in particular, completely new perspectives have been developed for their use in peptide chemistry, combinatorial chemistry, and heterocyclic synthesis. Organic azides have assumed an important position at the interface between chemistry, biology, medicine, and materials science. In this Review, the fundamental characteristics of azide chemistry and current developments are presented. The focus will be placed on cycloadditions (Huisgen reaction), aza ylide chemistry, and the synthesis of heterocycles. Further reactions such as the aza-Wittig reaction, the Sundberg rearrangement, the Staudinger ligation, the Boyer and Boyer-Aubé rearrangements, the Curtius rearrangement, the Schmidt rearrangement, and the Hemetsberger rearrangement bear witness to the versatility of modern azide chemistry.
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Affiliation(s)
- Stefan Bräse
- Institut für Organische Chemie, Universität Karlsruhe TH, Germany.
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15
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Quast H, Aldenkortt S, Freudenreich B, Schäfer P, Peters EM, Peters K, von Schnering HG, Würthwein EU. Ring Opening Reactions of Iminoaziridines and Aminoazirinium Ions. Is Electrocyclic Ring Opening of 2H-Azirinium Ions a Myth? European J Org Chem 2006. [DOI: 10.1002/jlac.199619960114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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16
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Grandel R, Kazmaier U, Nuber B. anti-Selective Aldol Reactions of Amino Acid Ester Enolates. Application to the Synthesis of α-Alkylated β-Hydroxy Amino Acids. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/jlac.199619960713] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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17
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Bräse S, Gil C, Knepper K, Zimmermann V. Organische Azide - explodierende Vielfalt bei einer einzigartigen Substanzklasse. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200400657] [Citation(s) in RCA: 346] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Hugener M, Heimgartner H. Bortrifluorid-katalysierte Umsetzungen von 3-Amino-2H-azirinen mit Aminosäure-estern und Aminen. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19950780716] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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19
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Schläpfer-Dähler M, Mukherjee-Müller G, Heimgartner H. Ring-Transformation von Imidazolidin-2,4-dionen ( = Hydantoinen) zu 4H-Imidazolen bei der Umsetzung mit 3-(Dimethylamino)-2,2-dimethyl-2H-azirin. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19920750425] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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20
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Hugener M, Heimgartner H. Eine überraschende Ringerweiterung von 3-(Dimethylamino)-2,2-dimethyl-2H-azirin zu 4,5-Dihydropyridin-2(3H)-on-Derivaten. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19950780720] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Obrecht D, Spiegler C, Schönholzer P, Müller K, Heimgartner H, Stierli F. A New General Approach to Enantiomerically Pure Cyclic and Open-Chain (R)- and (S)-α,α-Disubstituted α-Amino Acids. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19920750522] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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22
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Rahm A, Linden A, Vincent BR, Heimgartner H, Mühlstädt M, Schulze B. Ringerweiterung von 1,2-Thiazol-3(2H)-on-1,1-dioxiden und 3-Amino-2H-azirinen zu 4H-1,2,5-Thiadiazocin-6-on-1,1-dioxiden. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19910740511] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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23
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Schläpfer-Dähler M, Heimgartner H. Ring-Transformationen bei der Umsetzung von 3-(Dimethylamino)-2,2-dimethyl-2H-azirin mit 1-substituierten Imidazolidin-2,4,5-trionen. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19930760617] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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24
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Schläpfer-Dähler M, Heimgartner H. Ringerweiterung von sechs- zu neungliedrigen Heterocyclen: Umsetzung von 3-(Dimethylamino)-2,2-dimethyl-2H-azirin mit 3,4-Dihydro-2H-1,2,4-benzothiadiazin-3-on-1,1-dioxiden. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19930760626] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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25
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Hugener M, Heimgartner H. 4-Amino-1,5-dihydro-2H-pyrrol-2-one aus Bortrifluorid-katalysierten Umsetzungen von 3-Amino-2H-azirinen mit Carbonsäure-Derivaten. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19950780608] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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26
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Hilty F, Brun K, Heimgartner H. A New 2H-Azirin-3-amine as a Synthon for?-Methyl Glutamate. Helv Chim Acta 2004. [DOI: 10.1002/hlca.200490226] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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27
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Abstract
Alpha-halo-alpha-heteroarylalkyllithiums, generated by deprotonation of the corresponding halides, when added promptly to steroids with C=O or C=NR groups, lead to epoxides and aziridines. The reactions are regio- and stereoselective; in fact, in the presence of more than one C=O group, the oxido or aziridino functions are formed uniquely at the C=O of C-17 (or C-20 depending on its position in the starting molecule), and the C-20(R) stereoisomer is often the only product isolated. Protection of the hydroxyl group present on several considered steroids was required, and it was accomplished through derivatization in acetyl, ether, or lactone.
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Affiliation(s)
- Luigino Troisi
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, University of Lecce, Via Prov.le Lecce, Monteroni, I- 73100 Lecce, Italy.
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28
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29
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Azirines and aziridines revisited. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s1527-4640(00)80008-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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30
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Haufe G, Wilhelm Laue K, Ulrich Triller M, Takeuchi Y, Shibata N. Synthesis of γ-fluoro-α-methyl-α-amino acids. A new alkylation procedure for ester imines. Tetrahedron 1998. [DOI: 10.1016/s0040-4020(98)00292-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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31
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Albrecht E, Mattay J, Steenken S. [3 + 2] Cycloadditions and Protonation by Alcohols of Photochemically Generated Nitrile Ylides from 2H-Azirines. Formation and Reactivities of Azaallenium Cations. J Am Chem Soc 1997. [DOI: 10.1021/ja971648n] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Evelyn Albrecht
- Contribution from the Institut für Organische Chemie der Universität Münster, Corrensstrasse 40, D-48149 Münster, Germany, Institut für Organische Chemie der Universität Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany, and Max-Planck-Institut für Strahlenchemie, D-45413 Mülheim, Germany
| | - Jochen Mattay
- Contribution from the Institut für Organische Chemie der Universität Münster, Corrensstrasse 40, D-48149 Münster, Germany, Institut für Organische Chemie der Universität Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany, and Max-Planck-Institut für Strahlenchemie, D-45413 Mülheim, Germany
| | - Steen Steenken
- Contribution from the Institut für Organische Chemie der Universität Münster, Corrensstrasse 40, D-48149 Münster, Germany, Institut für Organische Chemie der Universität Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany, and Max-Planck-Institut für Strahlenchemie, D-45413 Mülheim, Germany
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32
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Trost BM, Ariza X. Katalytische asymmetrische Alkylierung von Nucleophilen - asymmetrische Synthese α-alkylierter Aminosäuren. Angew Chem Int Ed Engl 1997. [DOI: 10.1002/ange.19971092323] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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33
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Chinchilla R, Falvello LR, Galindo N, Nájera C. Asymmetrische Synthese von α-Methyl-α-aminosäuren durch diastereoselektive Alkylierung optisch aktiver 6-Isopropyl-3-methyl-2,3-dihydro-6H-1,4-oxazin-2-one. Angew Chem Int Ed Engl 1997. [DOI: 10.1002/ange.19971090926] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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34
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35
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Schulze B, Illgen K. Isothiazol-1,1-dioxide - vom Süßstoff zum chiralen Auxiliar in der stereoselektiven Synthese. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/prac.19973390102] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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36
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Mihova TR, Linden A, Heimgartner H. Synthesis of 1,2,5-Thiadiazepine Derivatives by Ring Enlargement of 1,2-Thiazetidin-3-one 1,1-Dioxides with 3-Amino-2H-azirines. Helv Chim Acta 1996. [DOI: 10.1002/hlca.19960790803] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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37
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Bucher CB, Heimgartner H. Optisch aktive 3-Amino-2H-azirine als Bausteine f�r enantiomerenreine ??-disubstituierte ?-Aminos�uren: Synthese von Isovalin-Synthonen und Einbau in ein Trichotoxin-A-50-Segment. Helv Chim Acta 1996. [DOI: 10.1002/hlca.19960790713] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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38
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Kazmaier U. Synthesis of quaternary amino acids containing β,γ- as well as γ,δ-unsaturated side chains via chelate-enolate claisen rearrangement. Tetrahedron Lett 1996. [DOI: 10.1016/0040-4039(96)01104-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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39
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40
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Quast H, Aldenkortt S. A Novel Route to Racemic and Nonracemic Products of the Ugi Reaction: Synthesis of Ugi′s Labile α-Adducts from Iminoaziridines and Carboxylic Acids, and their Transformations. Chemistry 1996. [DOI: 10.1002/chem.19960020417] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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41
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Luykx R, Bucher CB, Linden A, Heimgartner H. Ein neues 3-Amino-2H-azirin als Aib-Pro-Baustein: Synthese des C-terminalen Nonapeptids von Trichovirin I 1B. Helv Chim Acta 1996. [DOI: 10.1002/hlca.19960790220] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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