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Journal ArticleDOI

Synthesis via sigmatropic rearrangement. 12. Total synthesis of (+)-dihydrocostunolide via tandem Cope-Claisen rearrangement

01 Dec 1986-Journal of Organic Chemistry (American Chemical Society)-Vol. 51, Iss: 26, pp 5503-5505
About: This article is published in Journal of Organic Chemistry.The article was published on 1986-12-01. It has received 45 citations till now. The article focuses on the topics: Sigmatropic reaction & Cope rearrangement.
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Journal ArticleDOI
TL;DR: A new iron(III) halide-promoted aza-Prins cyclization between γ,δ-unsaturated tosylamines and aldehydes provides six-membered azacycles in good to excellent yields.
Abstract: A new iron(III) halide-promoted aza-Prins cyclization between γ,δ-unsaturated tosylamines and aldehydes provides six-membered azacycles in good to excellent yields. The process is based on the consecutive generation of γ-unsaturated-iminium ion and further nucleophilic attack by the unsaturated carbon−carbon bond. Homoallyl tosylamine leads to trans-2-alkyl-4-halo-1-tosylpiperidine as the major isomer. In addition, the alkyne aza-Prins cyclization between homopropargyl tosylamine and aldehydes gives 2-alkyl-4-halo-1-tosyl-1,2,5,6-tetrahydropyridines as the only cyclic products. The piperidine ring is widely distributed throughout Nature, e.g., in alkaloids,1 and is an important scaffold for drug discovery, being the core of many pharmaceutically significant compounds.2,3 The syntheses of these type of compounds have been extensively studied in the development of new drugs containing six-membered-ring heterocycles.4 Reactions between N-acyliminium ions and nucleophiles, also described as amidoalkylation or Mannich-type condensations, have been frequently used to introduce substituents at the R-carbon of an amine.5 There are several examples that involve an intramolecular attack of a nucleophilic olefin into an iminium cation for the construction of a heterocyclic ring system.6 Traditionally, the use of hemiaminals or their derivatives as precursors of N-acyliminium intermediates has been a common two-step strategy in these reactions.6a Among this type of cyclization is the aza-Prins cyclization,7 which uses alkenes as intramolecular nucleophile. However, cy† X-ray analysis. E-mail address: malopez@ull.es. (1) (a) Fodor, G. B.; Colasanti, B. Alkaloids: Chemical and Biological PerspectiVes; Pelletier, S. W., Ed.; Wiley: New York, 1985; Vol. 23, pp 1-90. (b) Baliah, V.; Jeyarama, R.; Chandrasekaran, L. Chem. ReV. 1983, 83, 379-423. (2) Watson, P. S.; Jiang, B.; Scott, B. Org. Lett. 2000, 2, 3679-3681. (3) Horton, D. A.; Bourne, G. T.; Smythe, M. L. Chem. ReV. 2003, 103, 893-930. (4) Buffat, M. G. P. Tetrahedron 2004, 60, 1701-1729 and references therein. (5) Speckamp, W. N.; Moolenaar, M. J. Tetrahedron 2000, 56, 3187- 3856 and references therein. (6) (a) Hiemstra, H.; Speckamp, W. N. In ComprehensiVe Organic Synthesis; Trost, B. M., Fleming, O., Heathcock, C. H., Eds.; Pergamon: New York, 1991; Vol. 2, pp 1047-1081. (b) Speckamp, W. N.; Hiemstra, H. Tetrahedron 1985, 41, 4367-4416. (7) (a) Dobbs, A. P.; Guesne, S. J. J.; Hursthouse, M. B.; Coles, S. J. Synlett 2003, 11, 1740-1742. (b) Dobbs, A. P.; Guesne, S. J. J.; Martinove, S.; Coles, S. J.; Hursthouse, M. B. J. Org. Chem. 2003, 68, 7880-7883. (c) Hanessian, S.; Tremblay, M.; Petersen, F. W. J. Am. Chem. Soc. 2004, 126, 6064-6071 and references therein. (d) Dobbs, A. P.; Guesne, S. J. Synlett 2005, 13, 2101-2103. ORGANIC

1,854 citations

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11 Sep 2006
TL;DR: It is shown that domino reactions initiated by oxidation or reduction or reduction, as well as other mechanisms, can be inhibited by various materials, such as Na6(CO3)(SO4), Na2SO4, Na2CO3, and so on.
Abstract: Introduction Cationic domino reactions Anionic domino reactions Radical domino reactions Pericyclic domino reactions Photochemically induced domino processes Transition metal catalysis Domino reactions initiated by oxidation or reduction Enzymes in domino reactions Multicomponent reactions Special techniques in domino reactions

1,337 citations

Journal ArticleDOI
TL;DR: The organisch-chemische Synthese hat stets eine grose Faszination auf den Chemiker ausgeubt, und sie wird auch in Zukunft nichts von ihrer Bedeutung verlieren as discussed by the authors.
Abstract: Die organisch-chemische Synthese hat stets eine grose Faszination auf den Chemiker ausgeubt, und sie wird auch in Zukunft nichts von ihrer Bedeutung verlieren. Es ist eine Binsenweisheit, das alle Chemiker - und nicht nur die - auf die Synthese chemischer Verbindungen, mit denen sie arbeiten wollen, angewiesen sind. So ist die organisch-chemische Synthese heute mehr denn je die Schnittstelle von Organischer Chemie, Biologie. Biochemie, Medizin, Physik und Materialwissenschaft. Man sollte auch nicht vergessen, das die Grundlage der chemischen Industrie die Synthese ist. Fur den Synthetiker aus Leidenschaft aber ist die Synthese weit mehr als nur Mittel zu dem Zweck, Verbindungen in die Hand zu bekommen; sie ist Ausdruck seiner Kreativitat. Intelligenz und seines handwerklichen Konnens, aber auch seiner Ausdauer.

444 citations

Journal ArticleDOI
TL;DR: Asymmetric domino reactions are reviewed for the first time in this article, covering the classification and characteristics of these reactions together with the most important applications, showing that the concept of asymmetric Domino reactions has emerged as a powerful tool in asymmetric synthetic chemistry.

262 citations