烷基锂化合物和带有邻位导向基团 (Directed Metalation Group--DMG)的芳烃反应得到邻位金属中间体。好的邻位导向基团有很强的配位或螯合效应，导致邻位氢的酸性增强。
邻位金属中间体可以和各种亲电试剂反应，得到的产物的DMG可以复原，转化为其他基团，或直接除去。
一般情况下此类反应都是低温，强碱性条件，几乎完全的邻位选择性是此反应的特点。
反应机理
电子密度大的取代基与锂的相互作用，使得相邻的位置被选择性锂化。
DMG没必要必须是惰性基团:
反应实例
To a stirred solution of 3-phenylsydnone (1) (0.25 g, 1.54 mmol) in dry THF (100 ml) at
-78℃ under an atmosphere of dry nitrogen gas was added N, N, N’,
N’-tetramethylethylenediamine (0.29 ml, 1.93 mmol) then n-butyllithium (2.31 ml, 3.47
mmol, 15 M in pentane) dropwise. After 0.5 h, the appropriate
2-chloro-N-methoxy-N-methylacetamide (1.93 mmol) was added to the golden yellow
solution and, after a additional 1h, the mixture was quenched with aqueous hydrochloric acid
(100ml, 10% v/v) then extracted with dichloromethane (3*100 ml). the combined organic
layers were dried (MgSO4) and the solvent removed in vacuo to afford the corresponding
o-acylated sydnone 4as an oil which was puriied by colum chromatography to afford colorless
crystals. Yield 86%.
【Tetrahedron Lett.; EN; 39; 12; 1998; 1509-1512】
