86300-58-5Relevant academic research and scientific papers
Photochemistry of α,α,ω,ω-tetramethyl-1,2-cycloalkanediones; influence of the conformation of the diketo moiety on the photochemical behaviour
Verheijdt, Paul L.,Cerfontain, Hans
, p. 173 - 181 (2007/10/02)
A series of α,α,ω,ω-tetramethyl-1,2-cycloalkanediones, with a ring size varying between 4 and 8 C atoms (1a-e), together with 2,2,5,5-tetramethyl-3,4-hexanedione (2a), have been irradiated both in 2-propanol and in benzene in order to study the influence of the diketo conformation on the photochemical behaviour of 1,2-diketones.Irradiation of 1b-d in 2-propanol leads exclusively to photoreduction with formation of the corresponding acyloins via intermolecular H abstraction, whereas 1e and 2 yield predominantly the 2-hydroxycyclobutanone product via intramolecular H abs traction.The irradiations of 1a-e in benzene lead to different products for the six homologous cyclic 1,2-diketones.Mechanisms for the formation of the various products are proposed.It is concluded that the 1,2-diketones with Φ (ground state) 90 deg react, upon excitation, from a conformation having a planar cisoid and transoid diketo geometry, respectively.
