On the action of a Lewis acid, 2,2-dimethoxyethyl acrylate is readily transformed into a reactive cationic dienophile, and it reacts with dienes under mild conditions to give Diels-Alder adducts in good yields with high stereo-and/or regioselectivity. 2-Oxopropyl acrylate and 2-oxocyclopentyl acrylate are also found to be converted into alternative cationic dienophiles by a facile procedure.
2,2-Dimethoxyethyl acrylate, which is easily prepared by the Mitsunobu reaction, reacts with dienes at −78 °C in the presence of a Lewis acid such as titanium(IV) chloride to afford the corresponding DielsAlder adducts in high yields.