Photochemistry of N-(selenoalkyl)-phthalimides. Formation of N, Se-heterocyclic systems

GABRIELA OKSDATH-MANSILLA; ADRIÁN A. HEREDIA; JUAN E. ARGÜELLO; ALICIA B. PEÑÉÑORY

Photochemical and Photobiological Sciences

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2015 vol. 14 p. 726 - 726

1474-905X

variety of N-(selenomethyl)alkyl-phthalimides (alkyl = ?(CH2)n?; n = 2?5, 1a, b, d, e) and N-(selenobenzyl)propyl phthalimide (1c) were synthesized and their photochemistry was studied at λ = 300 nm. Steady-state photolysis and laser time-resolved spectroscopy studies confirmed that these reactions proceeded by direct or acetone-sensitized excitation followed by intramolecular electron transfer (ET) between Se atom and the phthalimide moiety. Two main pathways are possible after ET: proton transfer to the ketyl radical anion from the CH3Se+˙ or the CH2Se+ moieties, yielding the corresponding biradicals. Collapse of these biradicals yields cyclization products with the respective endo or exo selenium-containing heterocycles. Competition between both proton transfer processes depends on the chain length of the alkyl spacer between the phthalimide and Se groups as well as the size of the cycle being formed.