Synthesis of Symmetrical Poly(pyridin-2-yl)Ethane Ligands

Abstract

Reaction of lithium derivatives of pyridin-2-ylmethanes, (C₅H₄N)CRR′- Li⁺, with mercury(II) iodide results in precipitation of mercury, and formation of symmetrical poly(pyridin-2-yl)ethanes [(C₅H₄N)CRR′]₂ (R = H, R = Ph; R = Me, R′ = Ph; R = R′ = Me; R = C₅H₄N, R′ = H; R = C₅H₄N, R′ = Me). For [(C₅H₄N)CRPh]₂ (R = H, Me) mixtures of the meso and racemic diastereoisomers were found. Two of the products, [(C₅H₄N)CHPh]₂ and [(C₅H₄N)₂CH]₂, were obtained in high yield, and readily form palladium(II) acetate complexes, Pd(O₂CMe)₂{rac-[(C₅H₄N)CHPh]₂} and [Pd(O₂CMe)₂]₂[(C₅H₄N)₂CH]₂. The synthesis of 2-(1-phenylethyl)pyridine and a convenient route to bis(pyridin-2-yl)methane are described.