Unexpected Variations in Sites of Lithiation of N-(2-Methoxybenzyl)-pivalamide

Directed lithiation of N-(2-methoxybenzyl)pivalamide with two mole equivalents of t-BuLi in anhydrous THF at -78 degrees C followed by reactions with various electrophiles gave ring substitution, but ortho to the methoxy group rather than ortho to the pivaloylaminomethyl group, which was unexpected in view of earlier results reported with n-BuLi.