1.3 Dipolare additionen der nitriloxyde an carbonylverbindungen

1,3-Dipolar cycloaddition of nitrile oxides. II. Reactions with o-quinoid structures

“…Structure 8 is assigned. The addition to activated double bond has been previously observed (6). The availability of the carbon<arbon double bond for this reaction is more obvious in the case of o-tetrabromoquinone than in the case of phenanthrenequinone and its derivatives.…”

Synthesis and ring opening metathesis polymerisation of isoxazolino- and isoxazolidino-norbornenes

“…[13] An excess of norbornadiene was used to avoid 2:1 adducts resulting from nitrile oxide cycloaddition to both alkene units in the dipolarophile. Using this approach norbornadiene and ethoxycarbonylformonitrile oxide 3a, generated from ethyl chloro-oximidoacetate 4a, afforded a mixture of endo-and exoadducts 5a (15%) and 6a (67%), which were separated by chromatography (Scheme 1).…”

Unexpected Rearrangements of Bicyclic Pyrazolines Derived from 6,6-Diphenylpentafulvene

“…[7] The diarylnitrilimines 2 were prepared in situ by dehydrohalogenation of 1-aryl(chloro)methylene-2-phenylhydrazines. [8,9,10] 6,6-Diphenylpentafulvene (1) was synthesised by condensation of cyclopentadiene with benzophenone in a solution of CH 3 COONa according to G. Kresze et al [11] Cycloadducts 3 and 4. -General Procedure: To a magnetically stirred solution of fulvene 1 (10 mmol) and 1-aryl(chloro)methylene-2-phenylhydrazine 2 (10 mmol) in toluene (60 mL), was added a solution of triethylamine (6 mL) in the same solvent (10 mL) during 5 min.…”