- 1,3-Dipolar Cycloadditions, 86. Aromatic Azoxy Compounds and Strained Cycloalkenes
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4,4'-Dicyano- and 4,4'-dinitroazoxybenzene as well as benzocinnoline N-oxide combine with (E)-cyclooctene or (1E,5Z)-1,5-cyclooctadiene to give bicyclic 1,2,3-oxadiazolidines which undergo in situ 1,3-dipolar cycloreversion with opening of both rings.Azomethine imines are formed which are connected by a hexamethylene chain with an aldehyde function.These new 1,3-dipoles add to a second molecule of the strained cycloalkene and furnish derivatives of cyclooctapyrazole as 1:2 adducts in high yields.A 1,4 H-shift of the intermediate azomethine imine competes at low concentration of the (E)-cyclooctene and produces an 8-hydrazino-7-octenal as a 1:1 product.
- Huisgen, Rolf,Gambra, Francisco Palacios
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p. 2242 - 2255
(2007/10/02)
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