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Azo bridges from azines, XIV. Rigid polycycles with NN and CC functionalities

✍ Scribed by Hünig, Siegfried ;Kraft, Petra ;Klarner, Frank-Gerrit ;Artschwanger-Perl, Uwe ;Peters, Karl ;Von Schnering, Hans-Georg

Publisher: John Wiley and Sons
Year: 1995
Tongue: English
Weight: 596 KB
Volume: 1995
Category: Article
ISSN: 0947-3440
DOI: 10.1002/jlac.199519950244

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✦ Synopsis

Abstract

Bifunctional 9, 3, 17, and trifunctional 20 dienophiles have been subjected to Diels‐Alder reactions with 4H‐pyrazoles 8 or 14 with inverse electron demand to form monoadducts 13, 15, 18, and 21 and bisadducts 16, 19, and 26. Acid‐catalyzed reactions at 20°C occur according to 14 + 3 → 15 + 16 and 14 + 17 → 18 + 19. By contrast, the solution of barrelene (20) and 8 has to be subjected to 10 kbar and 130°C to give monoadduct 21 and bisadduct 26, In daylight 21 undergoes [2 + 2] cycloaddition to 27. The norbornene derivative 10 reacts with cyclopentadiene to form 13 which is obtained in higher yield by reaction of 10 with hexachlorocyclopenta‐diene and subsequent reductive dehalogenation of adduct 12. X‐ray analyses of 11 and 13 reveal only small differences in the structural parameters.

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## Abstract As an example of system A, compound 5 was reacted with several thiols. A radical route procedures transannular 1,4‐addition products (6a/b). In the presence of sulfur, the addition reaction is strongly enhanced, and a polar route yields 1,2‐adducts (7a/b). Structures 6a/b and 7a/b are s