Cu(II)-catalyzed highly enantioselective intramolecular cyclization of N-alkenylureas was developed for the concise assembly of chiral vicinal diamino bicyclic heterocycles. Facile removal of carbonyl group of the carbamido moiety allowed for ready access to enantioenriched cyclic vicinal diamines.
Palladium-Catalyzed Aerobic Oxidative Cyclization of Aliphatic Alkenyl Amides for the Construction of Pyrrolizidine and Indolizidine Derivatives
作者:Dan Yang、Kai-Yip Lo、Liu Ye
DOI:10.1055/s-0036-1588502
日期:2017.8
An efficient palladium-catalyzed aerobic oxidative cyclization has been developed to synthesize a variety of pyrrolizidine and indolizidine derivatives from simple aliphatic alkenyl amides in moderate to good yields. The reaction features the capability of accessing various N-heterocycles and the use of molecular oxygen (1 atm) as the green oxidant.
Several Convenient Methods for the Synthesis of 2-Amido Substituted Furans
作者:Albert Padwa、Kenneth R. Crawford、Paitoon Rashatasakhon、Mickea Rose
DOI:10.1021/jo026757l
日期:2003.4.1
Several new methods for the synthesis of differently substituted 2-amidofurans are described. The thermolysis of furan-2-carbonyl azide results in a Curtius rearrangement and the resulting furanyl isocyanate was trapped with various organometallic reagents. A second method consists of a C-N cross-coupling reaction of a bromo-substituted furan with various amides, carbamates, and lactams. The CuI-catalyzed
The synthesis of 5‐[(pentafluorosulfanyl)methyl]‐γ‐butyrolactones bearing different substituents at position 3 or 4 is reported. A silver‐promoted intramolecular cyclization of substituted 4‐chloro‐5‐(pentafluorosulfanyl)pentanoic acids allows the preparation of substituted SF5‐containing γ‐butyrolactones in up to 96 % yield.
Direct synthesis of amides from nonactivated carboxylic acids using urea as nitrogen source and Mg(NO<sub>3</sub>)<sub>2</sub>or imidazole as catalysts
作者:A. Rosie Chhatwal、Helen V. Lomax、A. John Blacker、Jonathan M. J. Williams、Patricia Marcé
DOI:10.1039/d0sc01317j
日期:——
A new method for the direct synthesis of primary and secondary amidesfrom carboxylic acids is described using Mg(NO3)2·6H2O or imidazole as a low-cost and readily available catalyst, and urea as a stable, and easy to manipulate nitrogen source. This methodology is particularly useful for the direct synthesis of primary and methyl amides avoiding the use of ammonia and methylamine gas which can be