Lewis acids such as Sn(OTf)(2), GaCl3, Sc(OTf)(3), and Al(OTf)(3) catalyzed ring-opening 1,5-addition reactions of aliphatic alcohols to dimethyl 2-vinylcyclopropane-1,1-dicarboxylate, resulting in moderate to high yields of methyl 4-alkoxy-2-methoxycarbony-1-5-hexenoates with a catalytic turnover number of up to 80. A deuterium-labeling experiment and comparison with the reactivity of dimethyl cyclopropane-1,1-dicarboxylate suggested that this reaction involves a 1,3-dipole intermediate stabilized by the donor and the acceptor substituents. The ring-opening addition of phenols demonstrated several reaction modes, including Friedel Crafts 1,5- and 1,7-additions.