Bis(trimethylsilyl)methane1

(Me3Si)2CH2

[2117-28-4]  · C7H20Si2  · Bis(trimethylsilyl)methane  · (MW 160.41)

(precursor of (Me3Si)2CHLi and Me3SiCH2Li, which are useful in Peterson alkenation reactions3)

Physical Data: bp 132-133 °C; d 0.752 g cm-3; n20D 1.41710.

Solubility: sol common organic solvents.

Form Supplied in: colorless liquid; commercially available.

Analysis of Reagent Purity: 1H NMR.

Purification: by distillation.

Handling, Storage, and Precautions: the reagent can be stored in a glass bottle.

Formation of Trimethylsilylmethyl Anion.

The carbon-silicon bond of bis(trimethylsilyl)methane can be cleaved by Sodium Methoxide in HMPA to form trimethylsilylmethylsodium, which subsequently reacts with ketones to form alkenes (eq 1).2

Similar reaction of bis(trimethylsilyl)phenylmethane (eq 2) gave triphenylethylene in 79% yield. Lithium methoxide can be used instead of sodium methoxide.

Formation of Bis(trimethylsilyl)methyllithium.

Bis(trimethylsilyl)methane can be metalated with Methyllithium3 or n-Butyllithium4 in the presence of N,N,N,N-Tetramethylethylenediamine to produce (Me3Si)2CHLi, which is a useful Peterson alkenation reagent (eq 3).

Related Reagents.

Tris(trimethylsilyl)methane.


1. (a) Fieser, M.; Fieser, L. F. FF 1975, 5, 617. (b) Fieser, M.; Fieser, L. F. FF 1979, 7, 396.
2. Sakurai, H.; Nishiwaki, K.; Kira, M. TL 1973, 4193.
3. (a) Grōbel, B.-T.; Seebach, D. AG(E) 1974, 13, 83. (b) Cook, M. A.; Eaborn, C.; Jukes, A. E.; Walton, D. R. M. JOM, 1970, 24, 52.
4. Carter, M. J.; Fleming, I.; FF 1976, 679.

Hideki Sakurai

Tohoku University, Sendai, Japan



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