A convenient and efficient route for the allylation of aromatic amines and α-aryl aldehydes with alkynes in the presence of a Pd(0)TPhCOOH combined catalyst system

The allylation of aromatic amines with alkynes proceeded smoothly in the presence of catalytic amounts of Pd(PPh₃)₄ and benzoic acid. The allylation products were obtained in high yields in a regio- and stereoselective manner. The effect of various groups on the nitrogen atom of anilines was studied. Regardless of the substituent (electron withdrawing or electron donating) on the aromatic ring, the reaction proceeded well. Various functionalities, including -CH₃, -OMe, -Cl, -CN, -COOMe, -NO ₂ and -COCH₃ were tolerated under the reaction conditions. Similarly, the allylation of α-aryl aldehydes proceeded well with the same level of regio- and stereoselectivity as the allylation of aromatic amines. This reaction provides the second example of the transition metal catalyzed direct α-allylation of aldehydes.