Aromatic substitution. Part XXIII. Reaction of some 3-substituted pyridines with alkyl-lithium compounds

Abstract

The reaction of methyl-, isopropyl-, and benzyl-lithium with pyridine and 3-picoline has been investigated quantitatively. Isomer ratios and total and partial rate factors have been determined. The selectivity is in the order benzyl-lithium phenyl-lithium > methyl-lithium > isopropyl-lithium. No activation of C-2 in 3-picoline was observed with the alkyl-lithium derivatives. The benzyl group substitutes at C-4 exclusively. Explanations for the observed data are given based on the reactivity and size of the attacking anions.