Photoreduction and a Cleavage of Aryl Alkyl Ketones

Frederick D. Lewis, James G. Magyar

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66 Scopus citations

Abstract

The photochemical a cleavage and reduction reactions of several aryl alkyl ketones have been investigated. Electron-releasing aromatic substituents decrease the excited state reactivity of ieri-alkyl aryl ketones toward both primary photoprocesses to a similar extent. The aromatic carbonyl 3(n, π∗) state is concluded to be responsible for a cleavage as well as hydrogen abstraction reactions. The rate constant for intermolecular hydrogen abstraction by the carbonyl triplet state decreases with α-methyl substitution. Pinacol and carbinol products are formed via the combination and disproportionation of ketyl radicals. A primary deuterium isotope effect on isobutyrophenone ketyl radical disproportionation of 2.7 is observed. α-Methyl substituents increase the percentage of carbinol products due to steric hindrance of free-radical combination.

Original languageEnglish (US)
Pages (from-to)2102-2107
Number of pages6
JournalJournal of Organic Chemistry
Volume37
Issue number13
DOIs
StatePublished - Jun 1 1972

ASJC Scopus subject areas

  • Organic Chemistry

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