Refernces
10.1002/anie.201708578
The research focuses on the asymmetric cycloisomerization of o-alkenyl-N-methylanilines to indolines through iridium-catalyzed C(sp3)-H addition to carbon-carbon double bonds. The study establishes a highly enantioselective method for the synthesis of indolines bearing quaternary stereogenic carbon centers at the 3-positions, using an iridium catalyst with a bidentate chiral diphosphine ligand. The experiments involved the reaction of N-methylanilines with o-alkenyl groups in the presence of an iridium catalyst precursor and various chiral phosphorus ligands, with toluene as the solvent at temperatures ranging from 80 to 135°C. The reactants included a range of N-methylaniline derivatives with different substituents on the aniline ring and the double bond. The analyses used to determine the success of the reactions included isolated yields, enantiomeric excess (ee) determined by supercritical fluid chromatography (SFC) with a chiral stationary phase column, and deuterium labeling experiments to probe the reaction mechanism. The study also proposed a reaction mechanism based on the experimental results, which involves rate-determining oxidative addition of the N-methyl C-H bond, followed by intramolecular carboiridation and reductive elimination.
10.1021/ol2011067
The research focuses on the development of an efficient approach to synthesize fused indolines, which are important structural motifs found in a variety of natural products and biologically active compounds. The study describes a cascade reaction involving 2-ethynylaryl methylenecyclopropane and sulfonyl azide, catalyzed by copper(I) iodide under mild conditions. This novel method provides a rapid and efficient route for generating fused indolines. The experiments involved optimizing reaction conditions, including the choice of copper catalyst, base, and solvent, with triethylamine and 1,4-dioxane being the most effective. The reaction's scope was explored with variously substituted reactants, and the products were analyzed using X-ray diffraction, NMR spectroscopy, and other characterization techniques to confirm their structures. The results demonstrated the versatility and efficiency of the method, with yields ranging from moderate to high depending on the substituents on the reactants.
10.1002/chem.200800210
The study explores the use of gold catalysis to synthesize various heterocycles, including chromans, dihydrobenzofurans, dihydroindoles, and tetrahydroquinolines. The researchers prepared furans containing ynamide or alkynyl ether moieties in the side chain and used gold-catalyzed transformations to achieve these syntheses at room temperature through fast reactions. The heteroatom directly attached to the intermediate arene oxides stabilized the intermediates, leading to highly selective reactions, even with mono-substituted furans. The study involved various chemicals, including lithiated furans for the introduction of side chains, oxiranes and enones for synthesis of alcohols, and dichlorovinyl ethers and toluenesulfonamides as starting points for ynamide syntheses. The gold-catalyzed reactions resulted in the formation of the desired heterocycles with good yields and selectivity, highlighting the efficiency and versatility of gold catalysis in organic synthesis.
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