The purpose of this study is to use ferrous chloride as catalyst for the condensation of 1,3-dicarbonyl compound, such as acetylacetone and dimethyl malonate, with aldehydes, such as butyaldehyde, iso-butyraldehyde, pentanal, etc and obtain a series of 2-methylene-1,3-dicarbonyl compounds derivatives like 3-butylidene-2,4-pentanedione, 3-(2-methylpropylidene)pentane-2,4-dione, 3-ethylidenepentane-2,4-dione, 3-pentylidenepentane-2,4-dione, 4-hydroxy-3-(2-phenylethenyl)- 3-penten-2-one, dimethyl 2-ethylidenemalonate, dimethyl 2-butylidenemalonate, dimethyl(2-methylpropylidene)malonate, 3-(2-thienylmethylene)pentane-2,4-dione, 3-(furan-2-ylmethylene)pentane-2,4-dione. One of the characteristics of this experiment is the mild reaction condition. Compared to the literature , which usually require solvents or higher reaction temperature, this method can be carried out at room temperature and no solvent is required.