Cesium carbonate CAS# 534-17-8

The numerous properties exhibited by cesium carbonate in organic synthesis stem from the softer Lewis acidity of the cesium ion, which allows it to be soluble in organic solvents such as alcohols, DMF, and ether. The better solubility in organic solvents allows cesium carbonate to participate as an effective inorganic base in chemical reactions catalyzed by palladium reagents such as the Heck, Suzuki, and Sonogashira reactions. For example, the Suzuki cross-coupling reaction was able to obtain 86% yield with the support of cesium carbonate, while the same reaction yielded only 29% and 50% with the participation of sodium carbonate or triethylamine. Similarly, in the Heck reaction of methacrylate with chlorobenzene, cesium carbonate showed very clear superiority over other inorganic bases such as potassium carbonate, sodium acetate, triethylamine, and potassium phosphate. Cesium carbonate also has a very important use in achieving O-alkylation reactions of phenol compounds. It is speculated that the O-alkylation reaction of phenol in non-aqueous solvents induced by cesium carbonate is likely to undergo phenoxy anion, and thus the alkylation reaction is equally possible for highly reactive secondary halogenates that are highly susceptible to elimination reactions. Cesium carbonate also has important applications in the synthesis of natural products, such as the use of cesium carbonate as an inorganic base to obtain closed-loop products in high yields in the key step of the closed-loop synthesis of Lipogrammistin-A compounds. In addition, the good solubility of cesium carbonate in organic solvents makes it important for use in solid-supported organic reactions. For example, it induces three-component reactions of aniline with solid-supported halogenates in a carbon dioxide atmosphere to synthesize carboxylic acid esters or carbamate compounds in high yields. Cesium carbonate as a base under microwave radiation also enables the esterification reaction of benzoic acid with solid-supported halogenates.