Caesium fluoride

Description

Cesium fluoride (CsF) has higher solubility than NaF or KF. Cesium is less electronegative than sodium or potassium and is larger in size, both properties which allow for easier dissociation from the fluorine ion. Cesium fluoride is less hygroscopic than other sources of highly dissociated fluorine such as TBAF. The moderately basic nature of fluorine also makes it useful as a base in certain reactions, especially when a non-nucleophilic base is desired.

Chemical properties

white crystalline powder

The Uses of Caesium fluoride

Used as a base in a Suzuki cross-coupling synthesis of ortho-substituted biaryls.5 Also employed as a reagent for nucleophilic fluorination of primary halides and sulfonates in protic media such as tert-butyl and tert-pentyl alcohols.6

The Uses of Caesium fluoride

To a solution of the bromide (1.2 g, 4.7 mmol) in dry DMF (36 mL) degassed with N2 was added Pd(PPh3)4 (270 mg, 0.23 mmol) and the stannane (1.85 g, 5.6 mmol). The mixture was flushed with N2 for 5 min, then stirred at 80 C overnight. After cooling, the mixture was partitioned between EtOAc and brine. The org layer was washed with brine (2x), dried, and concentrated to give 3.5 g of a yellow oil. The material was purified by Prep LC (80 g silica, 5-10% EtOAc/heptane) to provide the product as a colorless oil. [900 mg, 88%]

The Uses of Caesium fluoride

A preperation of building block for synthesis of fluoroallylic compounds.

The Uses of Caesium fluoride

Catalyst in oxidation reactions; as a solid base when adsorbed onto Celite, q.v. Fluoride source in organic synthesis. Inorganic scintillator.

The Uses of Caesium fluoride

Cesium fluoride is an inorganic compound with the chemical formula CsF, which is a hygmoscopic white salt. Cesium fluoride can be used as a source of fluoride anion for organic synthesis. Caesium has the highest electropositivity of all non-radioactive elements and fluorine has the highest electronegativity of all elements.

What are the applications of Application

Cesium fluoride is a preperation of building block for synthesis of fluoroallylic compounds

General Description

Cesium fluoride is an inorganic compound known to be a source of fluoride ion and a catalyst in organic synthesis. It has been used in many organic reactions like 1,4?elimination, desilylation, transesterification, acylation, nucleophilic aromatic substitution, etherification, cross?coupling reactions and so on.

Hazard

A poison.

Flammability and Explosibility

Not classified

Safety Profile

A poison. Incompatible with benzenediazonium tetrafluoroborate and difluoroamine. When heated to decomposition it emits toxic fumes of F-.

Purification Methods

Crystallise it from aqueous solution by adding ethanol.