Rikiya Sato

New formation of a 1,3-dipole in the reaction of adamantanone azine with triazolinediones: in connection with reactivity toward singlet oxygen

Abstract Tricyclo[3.3.1.1]decanone azine ( adamantanone azine ) reacts with 4-substituted 1,2,4-triazoline-3,5-diones under elimination of diazo adamantane to give a 1,3-dipole ( “azomethinimine” ), which on treatment with dipolahophiles affords the [ 2 + 3] -cycloadducts. The reaction is compared with singlet oxygen oxidation.

Reaction of singlet oxygen with azines: Implications for dioxirane intermediate

Abstract Photooxygenation of tricyclo[3.3.1.1]decanone azine (adamantanone azine) afforded, in addition to adamantanone, 4-oxahomoadamantan-5-one derived from a dioxirane intermediate via a non-radical pathway.

Reaction of singlet oxygen with indanone phosphazine: formation of ketone and lactone

Abstract Photooxygenation of 1,1,3,3-tetramethyl-2-indanone triphenyl-phosphazine afforded, in addition to the parent indanone and triphenylphosphine oxide, 2,2,5,5-tetramethyl-3,4-benzo-3-penten-5-olide from a carbonyl oxide intermediate and also gave light emission.

Singlet oxygen and triazolinedione addition to azines

Photooxygenation of azines, i.e., adamantanone azine ( 1 ) and benzonorborn-7-one azine ( 4 ), afforded in addition to the corresponding ketones, lactones derived from a carbonyl oxide intermediate via an electron transfer pathway. On the other hand, 4-substituted-1, 2,4-triazoline-3,5-diones ( TAD ) react with azine 1 to give a 1,3-dipole, an azomethinimine intermediate as nitrogen analogue of a carbonyl oxide, which afforded the [ 2+3 ]-cycloadducts in treatment with dipolarophiles. The mechanistic implications are discussed.

Reaction of singlet oxygen with 2-pyrazoline: implication for cation radical - superoxide ion pair intermediate

Abstract Kinetic studies on photosensitized oxygenation of 1,3,5-triaryl-2-pyrazolines show that an electron-transfer from the pyrazoline to singlet oxygen may take place to give a cation radical and superoxide ion pair. The reaction of pyrazoline cation radicals with superoxide ion shows the same product distribution with singlet oxygenation.