10.1007/s00706-013-0925-7
This research presents the development of a heterogeneous palladium catalyst supported by a polymerized functional ionic liquid for the reductive homocoupling of aryl halides. The purpose of the study was to create a recyclable catalyst that could selectively catalyze the formation of biaryls, which are important building blocks in pharmaceuticals and agrochemicals, under mild conditions. The researchers synthesized a homopolymer of 3-(cyanomethyl)-1-vinylimidazolium hexafluorophosphate and used it to support Pd nanoparticles, resulting in the Pd@poly-CN-PF6 catalyst. This catalyst was found to efficiently catalyze the homocoupling reactions of aryl halides in water at 100°C with good yields. The catalyst could be recycled and reused multiple times with only a slight loss in activity, which was attributed to palladium leaching at high temperature and aggregation of palladium nanoparticles. Key chemicals used in the process included 1-vinylimidazole, 2-chloroacetonitrile, potassium hexafluorophosphate, azodiisobutyronitrile (AIBN), and sodium borohydride (NaBH4) for the synthesis of the polymer and the Pd nanoparticles, as well as aryl halides, NaOH, and ascorbic acid in the catalytic reactions.
10.1021/jo901395m
The research study on the Birch Reductive Alkylation (BRA) of biaryls, focusing on the scope and limitations of this method for synthesizing symmetrical arylcyclohexadienes, which are valuable building blocks for the synthesis of alkaloids. The purpose of the research was to investigate the regioselectivity of the BRA process by varying the nature of substituents on the aromatic rings of biaryls, particularly electron-rich substituents like OMe, OH, and NR2 groups. The study concluded that high levels of regiocontrol could be achieved through careful selection of substituents, and that the BRA method is a valuable tool for organic synthesis, offering a straightforward entry toward cyclohexa-2,5-dienyl arene systems bearing a quaternary center. Key chemicals used in the process included various biaryl precursors, lithium in ammonia as the reducing agent, and a range of electrophiles such as R-chloroacetonitrile, N-tosylaziridine, esters, amides, nitriles, epoxides, acetals, and sterically hindered t-Bu groups and cyclopropyl substituents.
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