Thermal behaviour of aryl γ-haloprcpargyl ethers
TL;DR: In this article, a systematic study of the behavior of aryl γ-halopropargyl ethers under thermal condition was undertaken, and the results showed that the transformation of these compounds yielded a mixture of products including 4-bromochromenes and chroman-4-ones.
About: This article is published in Tetrahedron.The article was published on 1989-01-01. It has received 18 citations till now. The article focuses on the topics: Ether & Aryl.
Citations
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TL;DR: In this article, a mixture of NaBr and NaBrO3 in two different ratios have been used for highly stereoselective bromination of alkenes and alkynes, and regioselectively bromine substitution at the α-carbon of ketones and at the benzylic position of toluene derivatives.
107 citations
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TL;DR: Ru-catalyzed [2 + 2] cycloadditions between norbornadiene and alkynyl halides were found to occur in moderate to good yields and can be transformed into a variety of products that are difficult or impossible to obtain via directcycloaddition.
55 citations
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TL;DR: Cationic rhodium(I)-catalyzed intramolecular [4 + 2] cycloadditions of diene-tethered alkynyl halides were found to occur in good yields and could be transformed into a variety of products that are difficult or impossible to obtain via directcycloaddition.
45 citations
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01 Jan 199645 citations
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TL;DR: Ru-catalyzed cycloadditions between bicyclic alkenes and alkynyl halides were found to occur in moderate to good yields as mentioned in this paper, where the presence of the halide moiety greatly enhances the reactivity of the alkyne component in the cycloadding.
44 citations
References
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TL;DR: The Claisen rearrangement of aryl propargyl ethers in poly(ethylene glycol) -200 at 200°C affords products in good yields.
38 citations
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TL;DR: In this paper, a one-pot synthesis of 4-chlorochromenes and chroman-4-ones was achieved from γ-chloropropargyl aryl ethers proceeding through Claisen rearrangement, depending upon the solvent of choice.
23 citations
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TL;DR: Claisen Rearrangement of 2-Propinyl (3-Pyridyl) and Allyl (3pyridine) Ethers as mentioned in this paper showed that in both DMF and decane at 208° in a sealed tube, furopyridines and pyranopyridine were formed.
Abstract: Claisen Rearrangement of 2-Propinyl (3-Pyridyl) and Allyl (3-Pyridyl) Ethers1
2-Propinyl (3-pyridyl) ether (1), synthesized from the corresponding 3-pyridinol, was heated in DMF or decane at 208° in a sealed tube. In this way the furopyridines 2 and 3 were formed, and furthermore the pyranopyridine 4 if decane was used as solvent (Scheme 1). The same reactions took place with (2-methyl-3-pyridyl) 2-propinyl ether (14). In DMF only 15, and in decane 16 as well as 15 were formed (Scheme 3). The rearrangement of the pyridine derivative 17, which is substituted in both O-positions to the ether moiety, gave in both DMF and decane the diastereoisomeric tetracyclic compounds 18 and 19. The same kind of reaction took place with 25 (Scheme 4).
In the thermolysis of the allyl 3-pyridyl ether (27) cyclization was observed, too. The isolated product has the structure of the dihydrofuropyridine 28 (Scheme 6). The substituted allyl 3-pyridyl ether 30 reacted in the same way to the dihydrofuropyridine 31 (Scheme 6).
16 citations
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TL;DR: In this paper, the authors present synthesis and properties of 4-Chloro and 4-Bromo-2H-chromenes and of 3-Halo 2Hchromenes.
Abstract: Durch Abspaltung von Bromwasserstoff entstehen aus den trans-3.4-Dihalogen-chromanen die entsprechenden 4-Halogen-2H-chromene 1–4. Die 3-Brom-2H-chromene 5 und 6 erhalt man durch Dehydratisierung der cis-3-Brom-4-hydroxy-chromane.
Synthesis and Properties of 4-Chloro- and 4-Bromo-2H-chromenes and of 3-Bromo-2H-chromenes
Dehydrobromination of trans-3,4-dihalochromans yields the 4-halo-2H-chromenes 1–4. Dehydration of cis-3-bromo-4-hydroxychromans leads to the 3-bromo-2H-chromenes 5 and 6.
15 citations