Cesium carbonate: a versatile organic synthesis reagent

Cesium carbonate, with the chemical formula Cs2CO3, is an alkaline carbonate with a wide range of applications and has been shown to be a mild inorganic base in organic synthesis[1]. This is due to its unique ability to promote selective reactions without being stimulated by stronger bases such as alcohol salts, but its aqueous solution is strongly alkaline.

It was found that cesium carbonate has a unique catalytic ability on the reaction of carbonyl compounds with diphenyl diselenide to give the corresponding alpha-phenylseleno carbonyl compounds in moderate to good yields. Similarly, the alpha-phenylthiolation of carbonyl compounds with diphenyl disulfide was promoted by the cesium carbonate catalyst[2].

Non-transition metal borylation of aryl iodides with diboron (II) and (V) in the presence of cesium carbonate is readily achieved to produce aryl boron ethers in moderate yields[3].

Cesium carbonate mediated synthesis of 3-(α-hydroxyaryl)indoles can be used to synthesize a series of 3-(α-hydroxyaryl)indoles by reacting aromatic aldehydes with indoles in DMF using cesium carbonate as a catalyst[4].

Alumina-supported cesium carbonate is a highly active catalyst that can be used for the Michael addition reaction of active methylene compounds with acrylates[5]. The catalyst can be easily isolated by simple filtration and reactivated by calcination.

Cesium carbonate can also be used as a catalyst to promote the hydrolysis of hydrosilanes to produce silanols. This method for preparing silanols has many advantages, including mild reaction conditions, wide substrate compatibility, simple post-processing, high yield, and scalability to gram-scale synthesis[6].

References:

[1] VARALA R, ACHARI K M M, HUSSEIN M, et al. Cesium Carbonate (Cs2CO3) in Organic Synthesis: A Sexennial Update (2018 to Date)[J]. Current Organic Chemistry, 2024, 1 1. DOI:10.2174/0113852728325969240711105055.

[2] YUTAKA NISHIYAMA. Cesium carbonate-catalyzed alpha-phenylchalcogenation of carbonyl compounds with diphenyl dichalcogenide.[J]. Molecules, 2009: 3367-3375. DOI:10.3390/molecules14093367.

[3] JIEMING ZHANG; Jun L Z; Haihong Wu. Cesium Carbonate Mediated Borylation of Aryl Iodides with Diboron in Methanol.[J]. ChemInform, 2014, 496 1. DOI:10.1002/CHIN.201411192.

[4] RASOKKIYAM ELAYARAJA; R. J K. Cesium carbonate mediated synthesis of 3-(α-hydroxyaryl)indoles[J]. Tetrahedron Letters, 2012, 53 51: Pages 6901-6904. DOI:10.1016/j.tetlet.2012.10.002.

[5] TETSUNARI HIDA; Yoshihiro S; Kenichi Komura. ChemInform Abstract: Cesium Carbonate Supported on Alumina for the Michael Addition of Diethyl Malonate to Methyl Acrylates.[J]. ChemInform, 2011, 43 3. DOI:10.1002/chin.201203023.

[6] BAI Y, CHAI M, MA C, et al. Facile Synthesis of Silanols via Cesium Carbonate Catalyzed Hydrosilanes with Water[J]. Synthesis, 2024, 10 1. DOI:10.1055/a-2385-4181.