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.
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.
Mannich-type Reactions of in Situ Generated N-Acyliminium Ions from α-Amido p-Tolylsulfones with Silyl Enolates
作者:Sang-Hyeup Lee、Santosh T. Kadam
DOI:10.5012/bkcs.2011.32.10.3738
日期:2011.10.20
aliphatic aldehydes reactedwith silyl enol ether and silyl enol ester under mild reaction conditions to afford N-Cbz-protected β-aminoketones and N-Cbz-protected β-amino esters in moderate to good yield, respectively.Key Words : α-Amido p-tolylsulfone, Cbz-Protected β-amino ketone, N-Acyliminium ion, Mannich-type re-action IntroductionA Mannich and Mannich-typereactions are powerfulmethods for the synthesis