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Photooxygenation of oxygen‐substituted naphthalenes
Author(s) -
Bauch Marcel,
Krtitschka Angela,
Linker Torsten
Publication year - 2017
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.3734
Subject(s) - chemistry , lability , singlet oxygen , photooxygenation , photochemistry , naphthalene , alkoxy group , kinetics , oxygen , density functional theory , computational chemistry , medicinal chemistry , organic chemistry , alkyl , physics , quantum mechanics
The reaction of oxygen‐substituted naphthalenes with singlet oxygen ( 1 O 2 ) has been investigated, and labile endoperoxides have been isolated and characterized at –78°C for the first time. Low‐temperature kinetics by UV spectroscopy revealed that alkoxy and silyloxy substituents remarkably increase the rate of photooxygenations compared to 1,4‐dimethylnaphthalene, whereas acyloxy‐substituted acenes are inert towards 1 O 2 . The reactivities nicely correlate with HOMO energies and free activation energies, which we determined by density functional theory calculations. The lability of the isolated endoperoxides is due to their very fast back reaction to the corresponding naphthalenes even at –20°C under release of 1 O 2 , making them to superior sources of this reactive species under very mild conditions. Finally, a carbohydrate‐substituted naphthalene has been synthesized, which reacts reversibly with 1 O 2 and might be applied for enantioselective oxidations in future work.