Trifluoroacetophenone, photolysis

Reductive dunenzation to form fluorinated benzopinacols proceeds m the partly fluormated case either with zinc or by photolysis but is not observed with perfluorobenzophenone [651 (equation 53). Trifluoroacetophenone is reduced electrochemically in dimethylformamide to a stable radical anion, which, m the presence ot lithium ion, rapidly dunerizes to pinacol in higher yield than that available by photoreduction [66] (equation 54)... 

The primary act for the photochemical decomposition of trifluoroacetophenone (ref. 589) at A 3130 A is believed to be predominantly of Type 1, with the formation of benzoyl and trifluoromethyl radicals. On the other hand, a primary act of Type 2 has been proposed by Pritchard and Thommarson for the photolysis of hepta-fluoropropyl ethyl ketone. Studies on the photolysis of these and other fluorinated ketones showed many features in common with that of trifluoroacetone, but have also led to some interesting observations on radical-radical interactions. For example, Pritchard et identified the following reactions (leading to the formation of vinyl fluoride) during the photolysis of 1,3-difluoroacetone... 

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