(alpha-Diimine)PdCl+ species catalytically dimerize alkyl and silyl vinyl ethers to beta,gamma-unsaturated CH2=CHCH2CH(OR)(2) acetals, and they cyclize divinyl ethers to analogous cyclic acetals. A plausible mechanism comprises in situ generation of an active PdOR alkoxide species, double vinyl ether insertion to generate Pd{CH2CH(OR)CH2CH(OR)(2)} species, and beta-OR elimination to generate the acetal product. In the presence of vinyl ethers, (alpha-diimine)PdCl+ species can be used to initiate ethylene polymerization.