A series of new modular bifunctional chiral thiourea organocatalysts were synthesized from natural Cinchona alkaloids and amino acids, and their performance in the aza-Henry reaction of nitroalkanes to imines, the Michaeladdition of acetylacetone to nitroolefins and the Michaeladdition of acetone to nitroolefins was investigated. Under the mild conditions, the important building blocks β-nitro amines
Enantioselective aza-Henry reaction using cinchona organocatalysts
作者:Luca Bernardi、Francesco Fini、Raquel P. Herrera、Alfredo Ricci、Valentina Sgarzani
DOI:10.1016/j.tet.2005.09.076
日期:2006.1
The aza-Henryreaction of imines with nitromethane was promoted by cinchona alkaloids and modified cinchona bases to give optically active β-nitroamines. Various N-protected imines were examined as substrates. N-Boc, N-Cbz, and N-Fmoc protected imines gave the best results in terms of chemical yields and enantioselectivities. After a careful screening of a series of chiral bases, very good enantioselectivities
Bifunctional oxazoline-thiourea-based organocatalysts were synthesized and applied to the aza-Henryreactions between N-Boc aryl imines and nitromethane in high ee and chemical yields at room temperature.
合成了基于恶唑啉-硫脲的双功能有机催化剂,并将其应用于 N-Boc 芳基亚胺与硝基甲烷之间的 aza-Henry 反应,在室温下具有高 ee 和化学产率。
A Novel Bis-Thiourea Organocatalyst for the Asymmetric Aza-Henry Reaction
作者:Constantinos Rampalakos、William D. Wulff
DOI:10.1002/adsc.200800214
日期:2008.8.4
A novelbis-thiourea BINAM-based catalyst for the asymmetricaza-Henryreaction has been developed. This catalyst promotes the reaction of N-Boc imines with nitroalkanes to afford beta-nitroamines with good yields and high enantioselectivities. This catalyst has the advantage that it can be prepared in a single step from commercially available materials. A model is proposed for the catalyst action
Bottom-Up Synthesis of Supported Thioureas and Their Use in Enantioselective Solvent-Free Aza-Henry and Michael Additions
作者:José M. Andrés、Noelia de La Cruz、María Valle、Rafael Pedrosa
DOI:10.1002/cplu.201500476
日期:2016.1
Two sets of supported chiral thioureas, which differ in the length of the tether that connects the chiral appendage to the polymer structure and the effective functionalization, have been prepared by copolymerization of styrene, novel styryl thioureas derived from l-valine, and divinylbenzene. The efficiency of these polymeric thioureas has been tested in two different enantioselective transformations