Cerium(III) chloride catalyzed Michael reaction of 1,3-dicarbonyl compounds and enones in the presence of sodium iodide under solvent-free conditions

Cerium(III) chloride heptahydrate in the presence of sodium iodide catalyse s the Michael addition of 1,3-dicarbonyl compounds to alpha,beta-unsaturate d ketones and alpha,beta-unsaturated aldehydes with extraordinary efficienc y. The very mild conditions allow high chemoselectivity as shown by the abs ence of the typical side reactions, which can be observed in the convention al base-catalyzed processes. More interestingly, when at least one of the s tarting materials is liquid at room temperature, the reaction can also be p erformed without solvents. The CeCl3. 7H(2)O/NaI catalyst system can be eas ily separated from the reaction mixture and it can be reused without an app reciable loss of activity. Advantages of the present procedure, which utili zes cheap and "friendly" reagents, over the previously reported ones, are d iscussed.