Magnetite (Fe₃O₄) Nanoparticles‐Catalyzed Sonogashira– Hagihara Reactions in Ethylene Glycol under Ligand‐Free Conditions

Abstract

A novel application of nanoparticles of paramagnetic magnetite (Fe 3 O 4 ) as an efficient catalyst for carbon-carbon bond formation via the Sonogashira-Hagihara reaction under heterogeneous ligand-free conditions in ethylene glycol (EG) is des-A C H T U N G T R E N N U N G cribed. By using this catalyst, arylalkynes are produced from the reaction of aryl iodides and activated heteroaryl bromides with alkynes. The results are reproducible using the catalyst, which was prepared from different sources. The catalyst is easily separated by an external magnetic field from the reaction mixture. The separated catalyst can be recycled for several consecutive runs without appreciable loss of its catalytic activity.

Magnetic nanoparticles supported oxime palladacycle as a highly efficient and separable catalyst for room temperature Suzuki–Miyaura coupling reaction in aqueous media

“…[16][17] Formation of oxime 1 was confirmed using 1 H NMR from the reaction mixture of 1-(4-aminophenyl)ethanone oxime and triethoxy (3-isocyanatopropyl) silane (Scheme 2).…”

“…Recently, we have reported application of magnetite nanoparticles as an efficient catalyst for Sonogashira-Hagihara reaction under heterogeneous and ligand-free conditions in ethylene glycol. 16 Herein, for the first time, we report the use of magnetic nanoparticles as a catalyst support for immobilization oxime palladacycles and its application in room temperature SuzukiMiyaura cross-coupling reaction in aqueous media.…”

An odorless and efficient synthesis of symmetrical thioethers using organic halides and thiourea in Triton X10 aqueous micelles

“…The strongly basic aqueous medium could enhance the reaction rate by promoting the formation of the corresponding S-alkylisothiouronium salt (Table 1, Entries 1Á3) (9). After screening different surfactants, sodium dodecyl sulfate (SDS) provided a lower yield than TX10 and CTAB (Table 1, Entries 3Á5).…”

“…After screening different surfactants, sodium dodecyl sulfate (SDS) provided a lower yield than TX10 and CTAB (Table 1, Entries 3Á5). Presumably, the abstraction of an electron from OH ( by S-alkylimidothiocarbamate to form the S-alkylisothiouronium salt was impeded by the anionic micelle-forming agent SDS (9,15). TX10 is a cheap, non-toxic surfactant that is widely used in industry as the emulsifier and detergent, so further studies of this reaction were continued with TX10 aqueous micelles.…”

Sonogashira Reactions Using Nanocatalysts

“…123 Paramagnetic magnetite (Fe 3 O 4 ) nanoparticles were reported to act as efficient catalysts (5 mol%) for C C bond formation via the Sonogashira reaction under heterogeneous ligand-free conditions in ethylene glycol at 125 • C. By using this catalyst, arylalkynes such as 62 were produced from the reaction of aryl iodides and activated heteroaryl bromides, such as 5-bromopyrimidine (61), with terminal alkynes, such as phenylacetylene (Scheme 4.22). 124 Furthermore, the catalyst was separated after the reaction by an external magnetic field and reused for five consecutive runs without loss of catalytic activity. The addition of different amounts of palladium and copper impurities did not affect the final yield significantly, but the addition of different amounts of the iron nanoparticles affected noticeably, suggesting that the iron nanoparticles were really responsible for the catalytic activity.…”