Solid-Supported Palladium Catalysts in Sonogashira Reactions: Recent Developments

Abstract

Abstract:The Sonogashira cross-coupling reaction is the most frequently employed synthetic procedure for the preparation of arylated alkynes, which are important conjugated compounds with multiple applications. Despite of their rather high price, this reaction is usually catalyzed by palladium species, making the recovery and reuse of the catalyst an interesting topic, mainly for industrial purposes. Easy recycle can be achieved anchoring the palladium catalyst to a separable support. This review shows recent developments in the use of palladium species anchored to different solid supports as recoverable catalysts for Sonogashira cross-coupling reactions.

Supramolecular photocatalyst of Palladium (II) Encapsulated within Dendrimer on TiO2 nanoparticles for Photo‐induced Suzuki‐Miyaura and Sonogashira Cross‐Coupling reactions

“…These results proposed that the improved photoactivity predominantly benefits from the synergistic effects of Pd (II) amine‐terminated poly (triazine‐triamine) dendritic on TiO 2 nanoparticles that cause efficient separation and photogenerated electron–hole pairs and photoredox capability of nanocatalyst which all of these advantages due to the tuning of band gap of catalyst in the visible light region. It should be noted that there are many reports of cross‐coupling reactions catalyzed via homogeneous or heterogeneous processes, but most of them need to be conducted at elevated temperatures (≥100 °C), even under reflux conditions . This study shows that visible light irradiation can drive the same reactions on the Pd (II) [PTATAD] @ TiO 2 under much milder reaction conditions (27–30 °C), achieving good to excellent yields, and no additional additives such as co‐catalysts or phosphine ligands are required.…”

Palladium nanoparticles embedded chitosan/poly(vinyl alcohol) composite nanofibers as an efficient and stable heterogeneous catalyst for Heck reaction

“…All the products were confirmed by 1 H NMR spectroscopy. 1 H NMR data of Heck reaction products was shown as follows:…”

“…Palladium catalysts play an important role in industrial and academic synthetic chemistry for their high activity and selectivity in coupling, reduction, and hydrogenation reactions. 1,2 Although homogeneous palladium catalysts have attracted much attention for their high activity and selectivity, they are known easy to aggregate and precipitate in the catalysis procedure, which not only causes considerable loss of activity, but also contaminates the products. 3 Additionally, recovery and reuse of the expensive palladium is usually intricate and costly from the reaction mixture, and the residue palladium in the final products often restricts their application in the pharmaceutical, cosmetic, and food industries.…”

“…(E)-n-butyl cinnamate:1 H NMR (400 MHz, CDCl 3 ) δ 7.62 (d, J = 16.0 Hz, 1H), 7.50-7.42 (m, 2H), 7.36-7.29 (m, 3H), 6.38 (d, J = 16.0 Hz, 1H), 4.20-4.11 (m, 2H), 1.63 (dt, J = 14.6, 6.8 Hz, 2H), 1.45-1.29 (m, 2H), 0.91 (t, J = 7.4 Hz, 3H). (E)-n-butyl 3-(4-fluorophenyl)acrylate: 1 H NMR (400 MHz, CDCl 3 ) δ 7.64 (d, J = 16.0 Hz, 1H), 7.56-7.47 (m, 2H), 7.12-7.03 (m, 2H), 6.36 (d, J = 16.0 Hz, 1H), 4.21 (t, J = 6.7 Hz, 2H), 1.69 (dt, J = 14.6, 6.8 Hz, 2H), 1.51-1.36 (m, 2H), 0.97 (t, J = 7.4 Hz, 3H).…”

Bi2O3@mSiO2 as an Environmentally Benign and Sustainable Solid Acid Catalyst for Benzoylation of Aromatics: Impact of Silica Encapsulation on Catalyst Leaching and Reaction Synergy

“…This not only results in contamination of the product, but is also detrimental to the environment due to presence of toxic metals in the waste stream. The investigations range from simple hydrogenation reactions of alkenes and nitro compounds to cross‐coupling reactions like Heck, Suzuki, and Sonagashira, where leaching of the precious metals has been reported. Typical metal catalysts are known to have leaching rates of 5–10 % or higher, which represents a substantial economic burden on any catalytic process.…”