The instant invention involves a process for enhancing molecular mass of biomass reactants. The process comprises first forming a substituted or unsubstituted furfural from a biomass. The substituted or unsubstituted furfural is then reacted with an activated methylene compound in the presence of a catalyst and, if desired, a solvent to form a Knoevenagel product. The product may then be hydrogenated to products containing an alcohol, ether, aldehyde, or ketone functional groups or to an olefinic or aliphatic species wherein as much as all of the oxygen and/or nitrogen has been removed.