&Halo carbonyl compounds, including 8-halo acetals, are useful substrates in organic synthesis. 2 However, whereas the methods of synthesis of a-halo carbonyl compounds are numerous, it is apparently more difficult to obtain &halo derivatives which suffer spontaneous dehydrohalogenation if the conditions are too drastic. The main processes used, with some limitations, are olefin acylation3 and addition of hydrogen halides to a,@- ...