Search

Bisindoles (BIMs) were modulated as powerful N,N′ donor ligands for the copper-catalyzed Sonogashira reaction. Ligand screening experiments on 11 BIM compounds found that 3,3′-(4-chlorophenyl)methylenebis(1-methyl-1H-indole) (10%) efficiently accelerated CuCl (5%)-catalyzed cross-coupling of aryl iodides with terminal alkynes. A wide range of substituted aryl iodides and/or alkyl- and aryl-substituted terminal alkynes were examined, leading to the corresponding coupling products with yields up to 99%. An efficient and scalable protocol for the synthesis of BIM ligands on a gram scale, with extremely low catalyst loading of o-ClC6H4NH3+Cl−, was also developed with a reaction time of 20 min with yields up to 93%. This novel N,N′ ligand was air-stable, easily available and highly modulated with low copper loading. Copyright © 2016 John Wiley & Sons, Ltd.

Copper-catalyzed Sonogashira-type reactions were dramatically accelerated by introducing a catalytic amount of polycyclic aromatic hydrocarbon additive. This novel catalytic system features low copper loading (0.5 mol% < Cu < 5 mol%), broad reaction scope and remarkable substrate tolerance. Both aromatic and aliphatic terminal alkynes as well as diverse aryl iodides were employed in this transformation, affording respectable yields of the desired products. The novel Cu(OTf)2/pyrene system was subsequently employed to synthesize phenylacetylene-based fluorescent compounds. Copyright © 2015 John Wiley & Sons, Ltd.

A dramatic acceleration in copper-catalyzed Sonogashira-type reactions was observed when an organophosphate was used as additive. The catalyst systems featuring low copper loading (0.5 mol% < Cu < 5 mol%) gave Sonogashira-type products with a broad scope of aromatic and aliphatic terminal alkynes as well as aryl iodides in good to excellent yields. Among the organophosphate/copper catalytic systems, that of 4 mol% Cu(OTf)2/10 mol% (R)-(−)-1,1′-binaphthyl-2,2′-diyl hydrogenphosphate exhibited the highest catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd.

Two 4-coordinated titanocene complexes, [(η5-C5H5)2Ti(O,O′)(5-NO2-OCC6H3)] (I) and [(η5-C5H5)2Ti(2-OH-5-NO2-O2CC6H3)2] (II), have been synthesized by reaction of Cp2TiCl2 and 5-nitrosalicylic acid in aqueous media. Single-crystal X-ray analyses of I and II display the mononuclear forms of TiIV, and geometries at titanium atoms are distorted tetrahedrons, while the coordination environment at TiIV in complex I is different from that in complex II. Crystallographic characterization revealed that each of the complexes exhibits a three-dimensional framework constructed through weak interactions, which are H-bonding, π–π stacking and C–H·π interactions, but they differ greatly when forming the three-dimensional network structure in both complexes. The results show that the dramatic change of conditions has great effect on the molecular structure of 5-nitrosalicylate titanocene, thereby significantly influencing the weak interactions and the specific framework structure. Copyright © 2005 John Wiley & Sons, Ltd.