The lanthanum catalyst refers to either elemental lanthanum or lanthanum compounds that possess catalytic functions. Lanthanum typically has valences of 0, +1, +2, and +3. In most lanthanum catalysts, such as lanthanum oxide and lanthanum chloride, the valence of lanthanum is +3. Lanthanum not only enhances the activity of reactions in organic synthesis but also improves reaction selectivity and has unique catalytic properties. As a member of the lanthanide series, metallic lanthanum also demonstrates excellent catalytic effects. Notably, certain lanthanum compounds, including lanthanum oxides and lanthanum salts, are used in organic synthesis extensively.