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Abstract
Alkoxyallenes are easily available and versatile building blocks for the preparation
of a variety of natural products (terpenes, polyketides, alkaloids, amino acids, carbohydrates
etc.) originating from different classes. The synthetic use of the three allene carbon
atoms frequently follows the “normal” reactivity pattern showing that alkoxyallenes
can be regarded as special enol ethers. Additions of alcohols or amines to alkoxyallenes
form vinyl-substituted O,O- or N,O-acetals that are frequently used in ring-closing
metathesis reactions. This methodology delivers crucial heterocyclic units of the target
compounds. Enantioselective additions provide products with high enantiopurity.
Alternatively, an “Umpolung” of reactivity of alkoxyallenes is achieved by lithiation at
C-1 and subsequent reaction with electrophiles, such as alkyl halides, carbonyl
compounds, imines or nitrones. High stereoselectivity of the addition step can be achieved by substrate control
or auxiliary control. The high diastereo- or enantioselectivity is transferred to the subsequent acyclic or cyclic
products. The cyclization of primary addition products occurs efficiently under mild conditions and provides
functionalized dihydrofuran, dihydropyrrole or 1,2-oxazine derivatives. These are valuable intermediates for
the synthesis of a variety of heterocyclic natural products. Nazarov cyclizations or gold catalyzed rearrangements
allow the synthesis of five- and six-membered carbocyclic compounds that are also used for natural
product synthesis.
Dedicated to Dr. Reinhold Zimmer, a pioneer of alkoxyallene chemistry, on the occasion of his 60th
birthday.
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Affiliation(s)
- Volker Martin Schmiedel
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | - Hans-Ulrich Reissig
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
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Okala Amombo MG, Schade W, Reissig HU. Reactions of Lithiated Methoxyallene with Oxime Derivatives - Formation of 1,2-Oxazines and Functionalized Isoxazole Derivatives. ChemistrySelect 2016. [DOI: 10.1002/slct.201600680] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Marlyse Ghislaine Okala Amombo
- Institut für Chemie und Biochemie der Freien; Universität Berlin; Takustr. 3 14195 Berlin Germany
- Fachrichtung Chemie und Lebensmittelchemie der Technischen; Universität Dresden; 01062 Dresden Germany
| | - Wolfgang Schade
- Fachrichtung Chemie und Lebensmittelchemie der Technischen; Universität Dresden; 01062 Dresden Germany
| | - Hans-Ulrich Reissig
- Institut für Chemie und Biochemie der Freien; Universität Berlin; Takustr. 3 14195 Berlin Germany
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Ring Expansions of Activated Aziridines and Azetidines. TOPICS IN HETEROCYCLIC CHEMISTRY 2015. [DOI: 10.1007/7081_2015_159] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Lechel T, Reissig HU. New 5-Alkoxypyrimidine Derivatives from β-Alkoxy β-Keto Enamides and Ammonium Salts. European J Org Chem 2010. [DOI: 10.1002/ejoc.201000056] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Affiliation(s)
- Fabian Pfrengle
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany
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