10.1021/jo9025644
The research focuses on the development of a copper-catalyzed annulation reaction between 2-formylazoles and o-aminoiodoarenes, leading to the synthesis of substituted pyrrolo[1,2-a]quinoxalines and related heterocycles. This method provides a one-step route to these biologically active molecules, which are present in a growing number of pharmaceutical compounds. The reaction conditions were optimized using 2-iodoaniline and 2-formylpyrrole as starting materials, with the best results obtained using 1 equivalent of 2-formylpyrrole, 1.5 equivalents of 2-iodoaniline, 2 equivalents of K3PO4, 10 mol % CuI, 20 mol % sparteine, and NMP as the solvent at 130°C for 24 hours. The reaction was found to be effective for a variety of substituted aminoiodoarenes and formylazoles, including 2-formylimidazole, 2-formylbenzimidazole, and a 3-formylpyrazole. The synthesized products were analyzed using techniques such as high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR) spectroscopy, and high-resolution mass spectrometry (HRMS) to confirm their structures and purities.
10.14233/ajchem.2014.16244
The study focuses on the development of a novel catalytic enantioselective method for the synthesis of chiral organoboronates, which are valuable precursors for the preparation of enantio-enriched compounds. The researchers synthesized a novel compound, 1-[2-{(1R,2S)-2-(chloromethyl)cyclopropyl]ethyl}-4-methoxybenzene, through a cyclopropanation reaction using boronate complexes as nucleophiles. Key chemicals used in the study include N,N-diisopropylcarbamoyl chloride, 3-(4-methoxyphenyl)-1-propanol, n-butyl lithium (n-BuLi), allylboronic acid pinacol ester, (-) sparteine, N,N,N,N-tetramethyl-ethylenediamine (TMEDA), 1,3-bis(trifluoromethyl)-5-bromobenzene, N-chlorosuccinimide (NCS), and trichloroisocyanuric acid (TCCA). These chemicals served various purposes, such as reactants, catalysts, and reagents in the synthesis process, with the aim of achieving high yields and enantioselectivity in the production of the target chiral compound. The study also investigated the effects of temperature and the choice of aryllithiums and electrophiles on the yields and stereoselectivity of the reaction.
10.1039/b715323f
The research focuses on the enantioselective functionalization of the C-2′ position of 1,2,3,4,5-pentamethylazaferrocene, a derivative of ferrocene, using sparteine-mediated lithiation. The purpose of this study was to develop potential new ligands for asymmetric catalysis, leveraging the robust platform of ferrocenyl motifs for the synthesis of planar chiral ligands. The researchers achieved enantioselective functionalization with a range of electrophiles, resulting in products with yields between 76–93% and enantiomeric excess (ee) of approximately 80%. They further developed a kinetic resolution method to enrich the ee of the products to over 90%. The study also explored palladium-catalyzed cross-coupling reactions and the synthesis of novel C2-symmetric bis-pentamethylazaferrocene, which showed potential as a new ligand for asymmetric catalysis. Key chemicals used in the process included 1,2,3,4,5-pentamethylazaferrocene, s-BuLi, sparteine, and various electrophiles such as I2, Ph2CO, MeI, Ph2S2, and ZnCl2, among others. The conclusions emphasized the efficiency of the developed methods for synthesizing enantioenriched azaferrocene derivatives and their potential applications in asymmetric catalysis.
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