Highly modulated bisindoles: ligands for copper‐catalyzed Sonogashira reaction

Abstract

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-ClC 6 H 4 NH 3 + Cl À , 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.

Ytterbium (III) triflate/Sodium Dodecyl Sulfate: A Versatile Recyclable and Water‐Tolerant Catalyst for the Synthesis of Bis(indolyl)methanes (BIMs)

“…Bis(indolyl)methane derivatives (BIMs) are a very attractive target in pharmaceutical chemistry in particular, for example bis(5‐methoxyindol‐3‐yl)methane (1), Figure , considerably reduces the growth of cancer cell lines . Besides pharmaceutical chemistry, BMIs have applications in coordination chemistry, e. g. Gao et al ., reported the synthesis of a series of BIMs as N,N ' donor ligands for the copper‐catalyzed Sonogashira coupling reaction, the p ‐chlorobenzyl bearing compound (2) was found to efficiently catalyze the reaction. The versatility of these compounds can also be seen in the complexes formed by BIMs (3) and radioactive metal ions (Ga 3+ ), which are employed as contrast agents for radio‐imaging and visualization of several tissues and organs (Figure ).…”

Highly active cobalt(II) and copper(II) complexes supported by aminomethylquinoline mediating stereoselective ring‐opening polymerization of rac‐lactide

“…However, herein, [LMCl 2 ] /LiO i Pr and [LMCl 2 ] /LiMe (M = Co, Cu, Zn) systems provided 97% conversion within 10 min with better stereoregularity of the resultant PLA without adding BnOH or i PrOH. In a study by Zhang et al, amino‐bis(phenolate)‐derived Co(II) afforded high molecular weight and atactic PLA with 92% conversion under melt conditions and longer reaction times 19 . Thus, our complexes were superior in activity and stereoselectivity.…”

“…Here, we discuss the impact of the initiating groups, LiMe and LiO i Pr on the ROP properties of Co(II) and Cu(II) complexes containing an aminomethylquinoline (L) ligand. Capitalizing on the precedence of effective Co‐ and Cu‐based catalysts in the ROP of rac ‐LA, 11,16,18,19 we synthesize mononuclear Co(II) and Cu(II) complexes to investigate the effect of geometry and the initiating group on the activity and stereoselectivity toward the ROP of rac ‐LA. We also compared the polymerization results with those of the Zn(II) system with the same ligand architecture and tetrahedral geometry.…”

Biomass Waste-Derived Pd–PiNe Catalyst for the Continuous-Flow Copper-Free Sonogashira Reaction in a CPME–Water Azeotropic Mixture

“…Specifically, in the Sonogashira cross-coupling, a mixture of an organic solvent and water is used as it allows the solubilization of the halide salts stoichiometrically produced in the process. However, these mixtures cannot be easily recovered leading to additional complicated issues arising from the disposal of hazardous waste. − …”