Aggregative activation in heterocyclic chemistry .4. Metallation of 2-methoxypyridine: unusual behaviour of the new unimetal superbase BuLi-Me2N(CH2)(2)OLi (BuLi-LiDMAE)

A series of potential unimetal superbases BuLi-ROLi has been studied in order to increase the basicity/ nucleophilicity ratio ([B/N]R) of BuLi, The best [B/N]R ratio is found with BuLi-LiDMAE, This complex base apparently metallates 2-methoxypyridine at the unexpected Cd position, It is shown that no actual metallated species are formed in the reaction medium, the reaction occurring as the result of a common radical precursor stabilized by an aggregate cluster. Finally, as an application, Ca substituted 2-methoxypyridines have been obtained in good to excellent yields.