2 research outputs found
Novel photochemical reactions of carbocyclic diazodiketones without elimination of nitrogen – a suitable way to N-hydrazonation of C–H-bonds
The sensitized photoexcitation of 2-diazocyclopentane-1,3-diones in the presence of THF leads to the insertion of the terminal N-atom of the diazo group into the α-С–Н bond of THF, producing the associated N-alkylhydrazones in yields of up to 63–71%. Further irradiation of hydrazones derived from furan-fused tricyclic diazocyclopentanediones culminates in the cycloelimination of furans to yield 2-N-(alkyl)hydrazone of cyclopentene-1,2,3-trione. By contrast, the direct photolysis of carbocyclic diazodiketones gives only Wolff rearrangement products with up to 90–97% yield
Light-Induced Reactions of Diazotetrahydrofuranone without Elimination of Nitrogen: Experimental and Mechanistic Study
The
energies and lifetimes of the excited states (S<sub>1</sub>, S<sub>2</sub>, S<sub>5</sub>, T<sub>1</sub>) of a diazotetrahydrofuranone
were determined using experimental and computational methods. It was
shown that direction of the diazoketone photochemical transformations
without elimination of nitrogen is determined by multiplicity and
energy of the excited state, generated by UV irradiation of diazo
compound: isomerization to α-ketodiazirine proceeds from the
singlet S<sub>1</sub> state, whereas the alternative process of C–H
insertion with hydrazone formation occurs through the triplet T<sub>1</sub> state. The most probable excited state that leads to elimination
of nitrogen and Wolff rearrangement is one of the highest singlet
excited states of diazotetrahydrofuranone