91309-48-7Relevant academic research and scientific papers
Temperature Dependence in the Sensitized Photoreaction of 3,3-Dimethyloxepin-2(3H)-one and 2,2,7,7-Tetramethylcyclohepta-3,5-dien-1-one
Hoshi, Nobuto,Uda, Hisashi,Sato, Kazuhiro,Hagiwara, Hisahiro
, p. 769 - 773 (2007/10/02)
The triplet-sensitized photolysis of the title compounds (1) and (4) has been studied at various temperatures. 3,3-Dimethyloxepin-2(3H)-one (1) gave rise to the cyclisation product 4,4-dimethyl-2-oxabicyclohept-6-en-3-one (2) (major), and the 1,2-acyl shift product 7,7-dimethyl-3-oxabicyclohept-4-en-2-one (3) (minor, hept-6-en-3-one (5), which is a hitherto unobserved product in the experiment run at room temperature, was produced at lower temperatures (34percent at -60 deg C).The results indicate that the thermodynamic activation parameters of each substrate in such systems play an important role in the preference of either of two competing photoprocesses, cyclisation or 1,2-acyl shift.A similar phenomenon was also observed in the photoreaction of 2,2,7-trimethyl-7-phenylcyclohepta-3,5-dien-1-one (11).
