2-Hydroxymethyl-but-1-ene-3-one [alpha-hydroxymethyl methyl vinyl ketone (HMVK)] was synthesized from methyl vinyl ketone using paraformaldehyde and a tertiary amine catalyst. Free-radical polymerization of this monomer created transparent, tough polymers that were insoluble in organic solvents. HMVK was converted to trimethylsilyl, acetate, and chloride derivatives. When the hydroxyl group was thus protected or removed, all these monomers could be free radically polymerized in bulk to make soluble polymers. The chlorination reaction is complicated by the formation of 1,1-bischloromethylacetone, which dehydrohalogenated unexpectedly to the desired alpha-chloromethyl methyl vinyl ketone. HMVK will self-condense to an ether dimer in the presence of a catalytic acid. This reagent is capable of crosslinking many alkene monomers through hydrolytically stable ether bonds.