Photosensitized Electron Transfer Promoted Reductive Activation of Carbon−Selenium Bonds To Generate Carbon-Centered Radicals: Application for Unimolecular Group Transfer Radical Reactions
- 1 January 1996
- journal article
- Published by American Chemical Society (ACS) in The Journal of Organic Chemistry
- Vol. 61 (20) , 6799-6804
- https://doi.org/10.1021/jo960805i
Abstract
The investigation presented in this paper explores the mechanistic aspects and synthetic potentials of photosensitized electron transfer (PET) promoted reductive activation of organoselenium substrates. PET activation of substrates 1 − 5 is achieved through a photosystem comprised of light-absorbing 1,5-dimethoxynaphthalene (DMN) as electron donor and ascorbic acid as co-oxidant. The fluorescence quenching of 1DMN* by organoselenium compounds 1 − 5, correlation of fluorescence quenching rate constant with the reduction potentials of 1 − 5, and the dependence of photodissociation quantum yields of 1 − 5 on their concentration suggests the occurrence of electron-transfer (ET) processes between 1DMN* and 1 − 5. Steady state photolysis of organoselenium substrates (R2CHSePh) in the presence of 1DMN* and ascorbic acid leads to the cleavage of the −C−Se− bond to produce a carbon-centered radical and PhSe- species via the intermediacy of R2CH−SePh⎤-•. The mechanistic interpretation for the reductive activation of −C−Se− bonds and the synthetic utility of observed cleavage pattern is extended for the unimolecular group transfer radical sequences.Keywords
This publication has 49 references indexed in Scilit:
- Mesolytic Scission of C-C Bonds in Radical Cations of Amino Derivatives: Steric and Solvent EffectsJournal of the American Chemical Society, 1995
- Fragmentations by photoinduced electron transfer. Fundamentals and practical aspectsPublished by Springer Nature ,1993
- Photosensitization by reversible electron transfer: theories, experimental evidence, and examplesChemical Reviews, 1986
- Behavior of radical ion pairs produced by photoinduced electron transfer in polar solutionsTetrahedron, 1986
- Photoelectron-transfer catalysis: its connections with thermal and electrochemical analogsChemical Reviews, 1983
- Mechanism and Spindynamics of Photoinduced Electron Transfer ReactionsZeitschrift für Physikalische Chemie, 1982
- Photoinduced Electron Transfer in Solution: Exciplex and Radical Ion Pair Formation Free Enthalpies and their Solvent DependenceZeitschrift für Physikalische Chemie, 1982
- Nuclear spin polarization effects in radical ion pair reactions. Comparison between triplet state and radical ion reactivityJournal of the American Chemical Society, 1981
- Ionic photodissociation of electron donor-acceptor systems in solutionAccounts of Chemical Research, 1981
- Photoinduced electron-transfer reactions. Radical cations of norbornadiene and quadricycleneJournal of the American Chemical Society, 1981