Method of producing C8-C15 hydrocarbons comprising providing a ketone starting material; providing an aldol starting material comprising hydroxymethylfurfural; mixing the ketone starting material and the aldol starting material in a reaction in the presence of a proline-containing catalyst selected from the group consisting of Zn(Pro)2, Yb(Pro)2, and combinations thereof, or a catalyst having one of the structures (I), (II) or (III), and in the presence of a solvent, wherein the solvent comprises water and is substantially free of organic solvents, where (I), (II) and (III) respectively are: where R1 is a C1-C6 alkyl moiety, X=(OH) and n=2. In (III), X may be CH2, sulfur or selenium, M may be Zn, Mg, or a lanthanide, and R1 and R2 each independently may be a methyl, ethyl, phenyl moiety.