Valenzisomerisierung von cis-Dienonen I. 2-Vinyl-3,4,5,6-tetrahydrobenzaldehyd; Pyrolyse. von 6-Oxabicyclo [3,1,0] hex-2-en [1] |
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| Authors: | P Schiess H L Chia |
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| Abstract: | The synthesis of 2-vinyl-3,4,5,6-tetrahydrobenzaldehyde ( 10 ) is described. This compound equilibrates above 70° with its valence isomer 4,5-tetramethylene-2H-pyran ( 11 ) as can be shown by cis-trans-isomerization of the double bond in selectively deuterated 10 . The unstable 2H-pyran 11 can be trapped as tetracyanoethylene adduct 12 . Gas phase pyrolysis of 6-oxabicyclo 3.1.0] hex-2-ene ( 18 ) at 400°C leads to cis-penta-2, 4-dienal ( 19 ) in fair yield. |
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