Efficient P, O chelate palladium(II)/AgNO₃ cocatalyzed homocoupling of aromatic terminal alkynes in aqueous media under ambient atmosphere

Magnetic copper ferrite catalyzed homo‐ and cross‐coupling reaction of terminal alkynes under ambient atmosphere

“…In order to show the merits and limitations of the present work in comparison with other reported catalytic systems in the literatures, we summarized some of results for the synthesis of 1,2‐diphenylethyne via homo‐coupling of phenylacetylene in Table . As can be seen in this table, the present catalytic system is an equally or more efficient to those previously reported in this reaction, since the use of precious metal catalyst, [12, 15,] high reaction temperature, or the employment of unrecyclable catalysts can be avoided.…”

“…The oxidative homocoupling reaction of terminal alkynes (Glaser‐Hay reaction) was one of the classical protocols for the synthesis of symmetrical conjugated 1,3‐diynes . Various catalytic systems have been developed for this reaction using O 2 or air as the oxidant, including the use of Cu, Pd, Ag, Au and bimetallic Pd/Cu, Pd/Ag and Fe/Cu . Some heterogeneous catalysts, like silica/chitosan core–shell hybrid‐microsphere‐supported CuI, copper nanoparticles supported on silica coated maghemite, copper immobilized on functionalized silica, polymer‐supported copper, Cu(I) immobilized on functionalized SBA‐15, immobilized copper in MCM‐41, mesoporous silica‐supported copper, copper immobilized on nano‐silica triazine dendrimer, copper‐impregnated magnetite have also been successfully employed to promote this reaction.…”

Palladium-Catalyzed Homo-Dimerization of Terminal Alkynes

“…Alternatively, a P,O-chelate Pd(II) 48/AgNO 3 co-catalytic system was employed for the oxidative dimerization of aromatic terminal alkynes with Et 3 N as the base in an aqueous medium under an ambient atmosphere (Scheme 41b). 68 Prior to this, Guo's group 69 had achieved a Pd(II)/AgNO 3 -co-catalyzed oxidative dimerization of aromatic terminal alkynes to afford satisfactory yields of the corresponding 1,3-diynes by using the palladium(II) complex 49, which was synthesized in an aqueous medium under aerobic conditions (Scheme 42).…”

An Efficient Synthesis of Arylated Pyridines from Conjugated Acetylenes and Substituted Benzylamines Catalyzed by Base

“…Peter [ 3 ] recently reported the site-selective arylation of commercially available 2,3,5,6-tetrachloropyridine using the Suzuki–Miyaura reaction, allowing the selective synthesis of mono-, di-, tri- and tetraarylated pyridines in good to quantitative yields. In this context, based on the advantages of conjugated acetylenes, which are readily prepared by the catalytic oxidative coupling of terminal alkynes [ 23 ], studying more efficient synthesis of pyridine derivatives between conjugated acetylenes and substituted methylamines is still highly desirable and challenging.…”