Treatment of 3, 3-dimethoxypropanal (2) with (acetylmethylene) triphenylphosphorane (4) gives (E)-6, 6-dimethoxy-3-hexen-2-one (5). Reaction of 5 with cyclopentadiene, 1, 3- cyclohexadiene, anthracene, and 1, 3-diphenylisobenzofuran gives Diels-Alder adducts, which on hydrolysis are converted to the corresponding keto aldehydes. Attempts to effect intramolecular aldol condensation of the latter were unsuccessful. Hydrolysis of the exo- ...
