64771-61-5Relevant academic research and scientific papers
Photooxygenation of Silyl Ketene Acetals: Dioxetanes as Precursors to α-Silylperoxy Esters in the Silatropic Ene Reaction
Adam, Waldemar,Wang, Xiaoheng
, p. 4737 - 4741 (2007/10/02)
Photooxygenation of silyl ketene acetals afforded dioxetanes, which subsequently underwent secondary reactions to give rearrangement products (α-silylperoxy esters, major products) and cleavage products (pivalaldehyde, minor product).The kinetics of these reactions were studied by NMR and chemiluminescence.The activation energy of the chemiluminescence cleavage process was 2-3 kcal/mol higher than that of the rearrangement.In the presence of catalytic amounts of CF3COCF3 or CF3COCH3, the (E)-silyl ketene acetals rearranged into their Z isomers.Photooxygenation of the (E)- and (Z)-silyl ketene acetals showed that the cycloaddition was rigorously diastereoselective.Trapping experiments with acetaldehyde confirmed the intermediacy of 1,4-zwitterions in the rearrangement of the (E)- and (Z)-dioxetanes into α-silylperoxy esters, but such intermediates were not detected during the photooxygenation of the silyl ketene acetals; the latter proceeds presumably via perepoxides.
