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8‐Oxabicyclo[5.1.0]octa‐2,4‐dien Thermische und lichtinduzierte Isomerisierung
Author(s) -
Schiess Peter,
Wisson Markus
Publication year - 1974
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19740570621
Subject(s) - chemistry , pericyclic reaction , benzene , bicyclic molecule , medicinal chemistry , benzaldehyde , pyrolysis , photochemistry , stereochemistry , organic chemistry , catalysis
8‐Oxabicyclo[5.1.0]octa‐2, 4‐diene ( 1 ) yields 2,4,6‐heptatrienaldehyde as major primary rearrangement product upon pyrolysis in a flow system between 200 and 300°. Above 500° o ‐cresol, benzaldehyde and benzene are obtained. Bicyclo[3.2.0]hept‐2‐en‐7‐one, 2,3‐ and 2, 5‐dihydrobenzaldehyde are shown to be intermediates in this transformation to stable aromatic products. The observed conversions can be rationalized as proceeding mostly through allowed pericyclic reaction steps with heterogeneous, acid catalysed reactions participating to a minor extent. Irradiation of 1 affords 3‐oxatricyclo[4.2.0.0 2,4 ]oct‐7‐ene, 2,4,6‐heptatrienal and 3,5‐cycloheptadienone. Upon sensitized irradiation only the latter two compounds are formed.