Photochemistry of diazo esters. II. Reaction path

Abstract

nitrosyl complexes. For similar concentrations of reagents, the reaction is distinctly slower than for the pentaammine complexes, suggesting that coordination of C104may be the initial step in this unusual reaction.

Wavelength-Dependent Photochemistry of Diazo Meldrum's Acid and Its Spirocyclic Isomer, Diazirino Meldrum's Acid: Wolff Rearrangement versus Isomerization

“…Wavelength dependence is a rarely observed phenomenon in organic photochemistry, as most photoreactions occur from the lowest singlet or triplet excited state of the molecule. , The composition of product mixtures in photolysis of diazo compounds, however, sometimes depends on the wavelength of irradiation . In most cases this dependence is due to the secondary photoreactions of primary products or due to a separate excitation of weakly interacting chromophores.…”

“…In most cases this dependence is due to the secondary photoreactions of primary products or due to a separate excitation of weakly interacting chromophores. There are only a handful of examples of “real” wavelength dependence, the phenomenon in which excitation to the lowest and higher excited states results in the formation of different products. 3b,c In this work we report a remarkable wavelength selectivity of photoreactions of diazo Meldrum's acid ( 1 ) and its diazirino isomer, 6,6-dimethyl-5,7-dioxa-1,2-diaza-spiro[2,5]oct-1-ene-4,8-dione ( 2 ) . We also demonstrate the first example of the direct photo-Wolff reaction of α,α‘-dicarbonyl diazirine.…”