Iodine has been found to be very effective catalyst for a Mannich reaction between an aryl aldehyde, an aryl ketone and benzyl carbamate, even though this is a less reactive amine, to produce Cbz-protected β-aryl β-amino carbonyl compounds in high yields.
reactions of aldehydes, ketones, and benzyl carbamate in the presence of a catalytic amount of (bromodimethyl)sulfonium bromide have been accomplished in short reaction time to afford the corresponding Cbz-protected ;8-amino ketones in high yields and good diastereoselectivity.
Highly Efficient Aza-Michael Reactions of Enones with Carbamates Using a Combination of Quaternary Ammonium Salts and BF<sub>3</sub>·OEt<sub>2</sub>as a Catalyst
作者:Chun-Gu Xia、Li-Wen Xu、Lyi Li、Shao-Lin Zhou、Jing-Wei Li、Xiao-Xue Hu
DOI:10.1055/s-2003-43333
日期:——
Aza-Michael reactions of enones with carbamates took efficiently in the presence of a catalytic amount of quaternary ammonium salts and BF 3 .OEt 2 to afford the total products in high yields. The new catalytic system was also efficient in the aza-Michael reaction of chalcone, which was difficult to react with carbamates by transition metal salts catalysts.
N-Benzyloxycarbonylamino sulfones react with aromatic ketones in the presence of catalytic amount of boron trifluoride-diethyl ether at room temperature to afford the corresponding protected β-amino ketones in high yields (71-87%). α-amido sulfones - stable imine precursors - aromatic ketones - BF3˙OEt2 - Lewis acids - β-amino ketones Part 200 in the series ‘Studies on Novel Synthetic Methodologies’
Heteropoly Acids Catalyzed Direct Mannich Reactions: Three-Component Synthesis of N-Protected β-Amino Ketones
作者:Xiaoxia Lu、Rui Wang、Taikun Huang、Lin Shi、Bogang Li
DOI:10.1055/s-2007-984913
日期:——
catalyzed one-pot three-component Mannich reactions of aryl aldehydes, aryl ketones, and carbamates at ambient temperature and afforded the corresponding N-protected beta-amino ketones in good to excellent yields. This method provides a novel and improved modification of three-component Mannich reactions in terms of a wide scope of aldehydes, ketones and carbamates, economic viability and reusability.