Reaction of sodium bis(trimethylsilyl)amide with bromotoluenes

Isomeric bromotoluenes react with sodium bis(trimethylsilyl)amide through intermediate methylbenzynes, yielding N,N-bis(trimethylsilyl)toluidines and rearrangement products, N,2-bis(trimethylsilyl)toluidines. The formation of the latter is a rare example of 1,3-migration of silyl group from nitrogen atom to aromatic carbon atom. The rearrangement is favored by increased solvent polarity and elevated temperature. The observed product ratio can be rationalized by DFT quantum chemical calculations.