Efficient P, O chelate palladium(II)/AgNO<sub>3</sub> cocatalyzed homocoupling of aromatic terminal alkynes in aqueous media under ambient atmosphere

<p>A new and efficient protocol for the P, O chelate Pd(II)/AgNO<sub>3</sub> cocatalyzed oxidative homocoupling reaction of aromatic terminal alkynes in the synthesis of symmetrical 1,4-disubstituted-1,3-diynes was described in aqueous media under ambient atmosphere. The results showed that both NEt<sub>3</sub> and THF/H<sub>2</sub>O (in 4:1 proportion) played crucial roles in the reaction. In contrast, this protocol employs a low palladium(II) complex loading and AgNO<sub>3</sub> as cocatalyst to obtain the homocoupled products in moderate to good yields.</p>