Photochemistry of 2-(cycloalk-1-enyl)cycloalkanones. A new photochemical reaction of βγ-unsaturated ketones
Abstract
On u.v. irradiation 2-(cyclohex-1-enyl)cyclohexanone (2) reacts by γ-hydrogen abstraction by the carbonyl oxygen atom and cyclobutane formation to form tricyclo[6.4.0.02,7]dodec-6-en-1-ol (4). In contrast, 2-(cyclohept-1-enyl)cycloheptanone (11) or 2-(cyclo-oct-1-enyl)cyclo-octanone (13) undergoes oxetan formation between the two double bonds giving 2-oxatetracyclo[8.5.0.01,9.03,9]pentadecane (12) or 2-oxatetracyclo[9.6.0.01,10.03,10]-heptadecane (14), respectively.