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Online-Ressource
Content:
Abstract: At 1 bar and 160°C the reaction of cyanoacetylene (1) with [2.2](2,5) furanoparacyclophane (3) produced the unexpected “ring‐enlarged” ketones 6–11. In the reaction of 1 with [8](2,5) furanophane (4) comparable products 21 and 22 were observed, in addition to the products 19 and 20 expected from a consecutive Diels‐Alder addition, Alder‐Rickert cleavage process and the Diels‐Alder addition of 1,4‐dicyano‐1,3‐cyclobutadiene (2a) to 4, respectively. In the reaction of 1 with the parent furan 5 only the (2:1) and (1:2) Diels‐Alder adducts 23, 25, 26, and 27 were found. High‐pressure experiments and the reactivity of 2‐cyano‐7‐oxabicyclo‐[2.2.1]hepta‐2,5‐diene (24), which was prepared independently by flow‐thermolysis of the (1:2) Diels‐Alder adducts 26 and 27, provide evidence that the (2:1) adducts 20, 23, and 13 are probably formed by a sequence of Diels‐Alder and [2 + 2] cycloadditions rather than by the reverse sequence starting with [2 + 2] cyclodimerization of 1 followed by Diels‐Alder reaction with cyclobutadiene 2a as postulated by the analogy to the trimerization of 1 and the cycloaddition of 1 to paracyclophane. The high‐pressure experiments led us to propose a new mechanism of formation of the “ringenlarged” ketones 6–11.
In:
volume:1997
In:
number:1
In:
year:2006
In:
pages:127-137
In:
extent:11
In:
Liebigs Annalen - recueil, Weinheim [u.a.] : Wiley, 1832-1997, 1997, Heft 1 (2006), 127-137 (gesamt 11)
Language:
English
DOI:
10.1002/jlac.199719970119
URN:
urn:nbn:de:101:1-2023122206243836252369
URL:
https://doi.org/10.1002/jlac.199719970119
URL:
https://nbn-resolving.org/urn:nbn:de:101:1-2023122206243836252369
URL:
https://d-nb.info/1314378317/34
URL:
https://doi.org/10.1002/jlac.199719970119
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