Potassium bis(trimethylsilyl)amide

Description

Potassium bis(trimethylsilyl)amide (KHMDS) is a sterically hindered strong base. It is commercially available as a solid and as a solution in a variety of solvents (ex. THF, 2Me-THF, toluene, and MTBE). Similar reagents include lithium bis(trimethylsilyl)amide (LiHMDS) and sodium bis(trimethylsilyl)amide (NaHMDS).

Chemical properties

Colorless to amber solution

The Uses of Potassium bis(trimethylsilyl)amide

Potassium bis(trimethylsilyl)amide is a strong base used in the alkylation carbonyl compounds.1

The Uses of Potassium bis(trimethylsilyl)amide

Potassium Bis(trimethylsilyl)amide (1M in THF) is used in the preparation of 5-azacytidine, an antineoplastic drug. Also applied in the preparation of β3-AR agonists used in anti-stress formulations. It is also used as a reagent in the preparation of lanthanide complexes employed in selective cyclization reactions.

The Uses of Potassium bis(trimethylsilyl)amide

To a suspension of the SM (52 mg, 0.2 mmol) in THF (4 mL) was added NaH (60%, 16 mg, 0.4 mmol) at 0 C, and the mixture was stirred for 15 min. To this mixture was added MeI (42 mg, 0.3 mmol) in THF (1 mL) dropwise at 0 C. The reaction mixture was warmed to RT and stirred for 4 h. The mixture was quenched with aq Na2CO3, extracted with EtOAc (3x), and washed with brine. Column purification (20-100% EtOAc/heptane) provided the product as an off-white powder. [31 mg, 60%]

The Uses of Potassium bis(trimethylsilyl)amide

Potassium Hexamethyldisilazide is widely used as a Sterically Hindered Base for Enolate Generation in Selective Formation of Linear Conjugated Dienolates and Alkyl (Z)-3-Alkenoates.

Preparation

Potassium Hexamethyldisilazide is prepared and isolated by the procedure of Wannagat and Niederpruem. A more convenient in situ generation from potassium hydride and hexamethyldisilane is described by Brown.

General Description

This product, 1.0 M in 2-methyltetrahydrofuran aligns with "Safer Solvents and Auxiliaries", "Use of Renewable Feedstocks" and "Inherently Safer Chemistry for Accident Prevention".