Copper(II)/Palladium(II) catalysed highly selective cross-coupling of terminal alkynes in supercritical carbon dioxide. Issue 15 (12th April 2018)

• Record Type: Journal Article
• Authors: Wang, Yunlong; Suo, Quanling; Han, Limin; Guo, Linlin; Wang, Yaqi; Li, Fawang
• Is Part Of: Tetrahedron. Volume 74:Issue 15(2018)
• Page Start: 1918
• Page End: 1925
• Publication Date: 2018-04-12
• Subjects: Supercritical CO2 -- Unsymmetrical diyne -- Terminal alkyne -- Bimetallic catalytic system -- Cross-coupling reaction; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2018.02.060
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: An efficient protocol for the synthesis of unsymmetrical 1, 3-diynes was developed using supercritical carbon dioxide (ScCO2 ) as the solvent. The direct coupling of two different terminal alkynes is catalysed by a bimetallic catalyst, CuCl2 ·2H2 O/Pd(NH3 )4 Cl2 ·H2 O, in the presence of the base tetramethylethylenediamine (TMEDA) and O2 . In pure ScCO2, our bimetallic catalytic system maintains high activity over a wide substrate scope to provide unsymmetrical 1, 3-diynes in good to excellent yields. In the proposed reaction mechanism, the synergistic cooperation between copper(II) and palladium(II) centres is responsible for the superior selectivity of the cross-coupling. Graphical abstract: