Ketones photoenolization, formation

Gebicki et al. have reported that lH-3H-exchange in o-methyl-substituted phenyl ketones is a valuable tool for probing the formation of transient photoenols. 

Hydrogen transfer, of which the foregoing are examples, is also important in the photoenolization of suitably substituted phenyl aldehydes and ketones. Thus Horii et a/.ea have reported formation of the enols (84), which could be... 

Irradiation of 2,5-dimethylbenzoyl oxiranes results in formation of p-hydroxy functionalized indanones (74) that structurally resemble biologically active pterosines. Nanosecond laser flash photolysis and quantum-chemical calculations based on density functional theory support a photoenolization mechanism.Reversible photochemical transformations of cis- and tra v-2,3-dimethyloxirane radical cations in freonic matrices at 77 K has been observed and explained by the interconversion between the open (C2-C3 broken) and the cyclic forms. Photocatalytic ring opening of a-epoxy ketones in cyclopentanone, using 2,4,6-triphenylpyrylium tetra-fluoroborate as electron acceptor, results in the diastereoselective formation of 2,5-dioxaspiro[4,4]nonanes through Ca-O bond cleavage and subsequent nucleophilic attack by cyclopentanone to the radical cation intermediates. ... 

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