An Efficient A3 Coupling Catalyst Based on a Silver Complex Bearing N-Heterocyclic Carbene and Homoscorpionate Bis(3-methyl-mercaptoimidazolyl)borate Ligands

Reaction of Ag(IPr)(Cl), 1 [IPr=1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene] with sodium precursors Na(mim) [mim=dihydrobis(methimazolyl)borate] and Na(Bb) [Bb=dihydrobis(2-mercapto-benzothiazolyl)borate] formed two novel silver complexes [Ag(IPr)(mim)], 2 and [Ag(IPr)(Bb)], 3. These complexes catalyzed three-component coupling reaction of a series of aldehydes with alkynes and amines. The efficiency of these novel catalysts compared with that of 1 and Au(IPr)(Cl), 4.