(Trimethylsilyl)methyllithium
methyllithium is classified both as an organolithium compound and an organosilicon compound. It has the empirical formula LiCH2Si3, often abbreviated LiCH2TMS. It crystallizes as the hexagonal prismatic hexamer 6, akin to some polymorphs of methyllithium. Many adducts have been characterized including the diethyl ether complexed cubane and .
Preparation
methyllithium, which is commercially available as a THF solution, is usually prepared by treatment of (trimethylsilyl)methyl chloride with butyllithium:methylmagnesium chloride is often functionally equivalent to methyllithium. It is prepared by the Grignard reaction of methyl chloride.
Use in methylenations
In one example of the Peterson olefination, methyllithium reacts with aldehydes and ketones to give the terminal alkene :Metal derivatives
methyllithium is widely used in organotransition metal chemistry to affix methyl ligands. Such complexes are usually produced by salt metathesis involving metal chlorides. These compounds are often highly soluble in nonpolar organic solvents, enjoying stability due to their steric bulk and resistance to beta-hydride elimination. In these regards, methyl is akin to neopentyl.Bismethylmagnesium is used as an alternative to methyllithium.
Related compounds
- bismethyllithium
- trismethyllithium