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Regioselective Addition of Copper-Zinc Aryl Organometallic Reagents to 3-Substituted Pyridinium Salts.-A series of 3-substituted pyridinium salts (12 examples) are subjected to the title reaction followed by oxidation to give the corresponding arylpyridines. In the presence of electrondonating groups as in (Ia) and (Ib), 4-arylpyridines (III) are formed exclusively, while pyridinium salts (IV) containing electron-withdrawing substituents afford mixtures of (V) and (VI). The disubstituted compound (Ic) gives only the 4-aryl derivative (IIIc) presumably because the C(6) position is blocked. The preferred γ-attack in the nucleophilic addition is explained by the attack of a soft nucleophile and rationalized by theoretical calculations. Since no general procedure for the preparation of 4-arylpyridines is known so far, the present method provides a valuable approach to the synthesis of 3-substituted 4arylpyridines. -(SHIAO, M.-J.; CHIA, W.-L.; SHING, T.-L.; CHOW, T. J.;

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