Sodium bis(trimethylsilyl)amide

Description

Sodium bis(trimethylsilyl)amide (NaHMDS) is a strong base. It is commercially available as a solid and as a solution in a variety of solvents (ex. THF, toluene, and MTBE). Similar reagents include lithium bis(trimethylsilyl)amide (LiHMDS) and potassium bis(trimethylsilyl)amide (KHMDS).

The Uses of Sodium bis(trimethylsilyl)amide

Sodium bis(trimethylsilyl)amide is a synthetically useful reagent in that it combines both high basicity and nucleophilicity, each of which may be exploited for useful organic transformations such as selective formation of enolates, preparation of Wittig reagents, formation of acyl anion equivalents, and the generation of carbenoid species. As a nucleophile, it has been used as a nitrogen source for the preparation of primary amines.It is useful as a sterically hindered base and as a nucleophile.

The Uses of Sodium bis(trimethylsilyl)amide

To a solution of the indole (A) (0.300 g, 0.92 mmol) in THF (30 mL) was added NaHMDS (1 M in THF, 0.93 mL, 0.93 mmol) at -78 C. The mixture was stirred at -78 C for 20 min, then at RT for 1 h. The alkyl chloride (B) (171 mg, 1.86 mmol) was added, and the reaction mixture was stirred at RT for another 18 h. The mixture was quenched with ice-H2O and extracted with EtOAc (3 x 30 mL). The combined organics were dried (Na2SO4) and concentrated to provide the product which was used in the next step without further purification. [0.300 g, 84%]