Acetyl radical fission

Other Fission Processes. - The photochemically induced fission reactions of a series of naphthylmethyl alkanoates have been described. Some factors that control the ease of bond cleavage within the esters were identified. Irradiation of (200) in a NaY zeolite using 308 nm light results in C-O bond fission and the formation of an acetyl radical. Irradiation of perfluoroacetyl fluoride at 254 nm in the gas phase brings about fission of CO-F bond with the formation of fluorine atoms and perfluoroacetyl radicals. ... 

Irradiation of acetoxystyrene (8) in hexane solution affords acetophenone (one of the products of a-fission presumably the other product, acetaldehyde is also present) and the diketone (9) (formed by what is formally a [l,3]-acetyl migration) as the primary photoproducts.Continued irradiation of the reaction mixture brings about cleavage of this diketone (9) into radical pairs (10, 11) which can either reform starting material [from radical pair (10)] or produce acetophenone as well as yielding isopropenyl benzoate (12) and benzoic acid [from radical pair (11)]. 

Acetyl chloride undergoes the expected fission into radicals (MeCO and Cl) when irradiated (254 nm) in ethereal solution.82 The major product (8) (72% at 18 °C) is formed by hydrogen abstraction and radical combination within the solvent cage. The other product (9) (28% at 18 °C) is formed by combination of two MeCHOEt radicals, presumably as a result of escape of this radical from the solvent cage in which it is formed. The proportion of (9) diminishes with decreasing temperature (21% at —45 °C). Propionyl chloride behaved similarly. Irradiation of the thioacetates (10) results in both S-alkyl and S-acyl bond cleavage.23... 

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