KHMDS

[Potassium Bis(trimethylsilyl)amide]

Other Names:

Potassium hexamethyldisilazide

Hexamethyldisilazane potassium salt

General Information:

Structure:

CAS Number: 40949-94-8

Molecular Weight: 199.48 g/mol

Appearance: White crystals

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).

Common Uses:

Strong, non-nucleophilic base in deprotonations (ex. substitution reactions)

Procedure excerpt:

To a solution of the SM (30 mg, 0.1 mmol) in THF (2.0 mL) at 0 C was slowly added KHMDS (25 mg, 0.1 mmol). The mixture was stirred for 10 min, after which time MeI . . .

[full procedure]

Safety:

The dry solid and solutions of potassium bis(trimethylsilyl)amide (KHMDS) are flammable and should be stored in the absence of moisture, and handled under an inert atmosphere.

References:

1) Patent Reference: WO2014149164, page 229, (23.7 MB)

2) Wikipedia: Potassium bis(trimethylsilyl)amide (link)

3) www.sigmaaldrich.com: Potassium bis(trimethylsilyl)amide solution (link)

4) Reich, H. J.; Rigby, J. H.; Handbook of Reagents for Organic Synthesis, Acidic and Basic Reagents