1,5-Dicarbonyl compounds and their enolsilylethers were prepared by the reaction of α,β-unsaturated ketones and enolsilylethers or ketenesilyl acetals by using an electrogenerated acid (EG acid) as a catalyst. Similar reaction of 1-trimethylsiloxy-1,3-butadiene with enones produced six-membered adducts as the result of a double-Michael process.
An annulation system based on sequential inter- and intramolecular Michael addition was realized by the combined use of ketone enolates and aluminum tris(2,6-diphenylphenoxide) (ATPH).