Gold-Catalyzed Intramolecular Cyclization ofN-Propargylic β-Enaminones for the Synthesis of 1,4-Oxazepine Derivatives
摘要:
An efficient and mild one-pot, gold-catalyzed intramolecular cyclization of N-propargylic beta-enaminones has been achieved for the generation of 1,4-oxazepine derivatives. This synthetic transformation tolerates a range of substituted N-propargylic beta-enaminones in moderate to good yields.
N-Propargylic β-Enaminones: Common Intermediates for the Synthesis of Polysubstituted Pyrroles and Pyridines
摘要:
N-Propargylic beta-enaminones have been used as common intermediates for the synthesis of polysubstituted pyrroles and pyridines. Best results have been obtained using DMSO as solvent. In the presence of CS(2)CO(3) N-propargylic beta-enaminones are cyclized to pyrroles in good to high yields, whereas omitting bases and using CuBr leads to the selective formation of pyridines.
N-Substituted formamides as nucleophiles react with in situ-generated 1,4-oxazepines from N-propargylic β-enaminones followed by spontaneous N-deformylation to deliver densely substituted 2-aminopyridines in good yields (31–88%). The formyl group is found to be a superior traceless activating group of free amines and would ultimately be removed in situ. This reaction proceeds smoothly at room temperature
A new strategy for the synthesis of pyridines from <i>N</i>-propargylic β-enaminothiones
作者:Yilmaz Kelgokmen、Metin Zora
DOI:10.1039/c8ob03180k
日期:——
A newmethod for the synthesis of 2,4,5-trisubstituted pyridines from N-propargylic β-enaminothiones is reported. β-Enaminothiones were prepared by thionation of the corresponding β-enaminones with Lawesson's reagent. When treated with diisopropylamine in DMF at room temperature, N-propargylic β-enaminothiones yielded 2,4,5-trisubstituted pyridines in moderate to high yields, along with small amounts
Base-mediated regiospecific cascade synthesis of N-(2-pyridyl)pyrroles from N-propargylic β-enaminones
作者:Jinhai Shen、Xifa Yang、Fuyuan Wang、Yue Wang、Guolin Cheng、Xiuling Cui
DOI:10.1039/c6ra08987a
日期:——
A KOH-promoted regiospecificsynthesis of polysubstituted N-(2-pyridyl)pyrroles under transition metal-free conditions has been developed. The pyrrole and pyridine rings were simultaneously installed from acyclic enaminone precursors under mild conditions and generated 1 equiv. of H2O as the sole byproduct. A series of polysubstituted N-(2-pyridyl)pyrroles were provided in up to 91% yield for 21 examples
Gold-catalysed cyclisation of N-propargylic β-enaminones to form 3-methylene-1-pyrroline derivatives
作者:Kommuru Goutham、N. S. V. M. Rao Mangina、Surisetti Suresh、Pallepogu Raghavaiah、Galla V. Karunakar
DOI:10.1039/c3ob42513d
日期:——
A gold(i) catalysed reaction between N-propargylic β-enaminones and arynes was developed to access 3-methylene-1-pyrrolines. The title compounds were obtained in 57–78% yields.