EDG (Me group) at o−,m− and p− positions: At ortho-position, ED power of (Me−) group is more than p and m (due to +I effect and hyperconjugation effect). ED power of (Me−) group at p-position is slightly less than the Me group at ortho-position (due to less +I effect, but equal hyper conjugative effect). So the order of ED power of (Me−) group is o>p>m−. NA is favoured by less-substituted EDG or more substituted EWG. So, the order of reactivity of PhMgBr with aromatic aldehyde is
