Synthesis of α-sulfanyl-β-amino acid derivatives by using nanocrystalline magnesium oxide
作者:M. Lakshmi Kantam、Koosam Mahendar、Bojja Sreedhar、Boyapati. M. Choudary、Suresh K. Bhargava、Steven H. Priver
DOI:10.1016/j.tet.2010.05.002
日期:2010.7
The Mannich-type reaction between alkyl, aryl and heterocyclic aldimines and sulfonium salts for the synthesis of α-sulfanyl-β-amino acidderivatives by using nanocrystalline magnesium oxide (NAP-MgO) is described. These products are obtained in moderate to high yields with moderate diastereoselectivities. The configuration of ethyl-3-[(4-methylphenyl)sulfonyl]amino}-2-(methylsulfanyl)-3-(4-nitrophenyl)propanoate
描述了烷基,芳基和杂环亚胺与M盐之间的曼尼希型反应,用于通过使用纳米晶状氧化镁(NAP-MgO)合成α-硫烷基-β-氨基酸衍生物。这些产品以中等至高收率获得,具有适度的非对映选择性。X射线衍射技术已证实3-[[(4-甲基苯基)磺酰基]氨基} -2-(甲基硫烷基)-3-(4-硝基苯基)丙酸乙酯(主要异构体)的构型是抗,并与基于1 H NMR光谱的赋值一致。这些α-硫烷基-β-氨基酸衍生物是具有强生物活性的药物的重要组成部分。
Transformations of 3-aryl-2-chloro-2-imidoylaziridines: novel entries to 4-chloro-2,5-diaryl-1H-imidazoles and 2-chloro-2-acylaziridines
作者:Filip Colpaert、Sven Mangelinckx、Nicola Giubellina、Norbert De Kimpe
DOI:10.1016/j.tet.2010.11.082
日期:2011.2
The reactivity of stereochemically defined 3-aryl-2-chloro-2-imidoylaziridines, an unexplored class of substituted aziridines, was investigated under various reaction conditions. 2-Chloro-2-imidoylaziridines underwent a novel thermal rearrangement by reflux in acetonitrile via C–C bond cleavage to 4-chloro-2,5-diarylimidazoles in high yield. Alternatively, a novel efficient entry toward 2-aroyl-2-chloroaziridines
Asymmetric Friedel−Crafts Reaction of Indoles with Imines by an Organic Catalyst
作者:Yong-Qiang Wang、Jun Song、Ran Hong、Hongming Li、Li Deng
DOI:10.1021/ja062700v
日期:2006.6.1
In this communication, we report an asymmetric Friedel-Craftsreaction of indoles with imines catalyzed by a bifunctional cinchona alkaloid catalyst. This is the first efficient organocatalytic asymmetric Friedel-Craftsreaction of indoles with imines. This reaction is operationally simple and, unprecedentedly, affords high enantioselectivity for a wide range of indoles and both aryl and alkyl imines
Chiral Guanidinium Salt Catalyzed Enantioselective Phospha-Mannich Reactions
作者:Xiao Fu、Wei-Tian Loh、Yan Zhang、Tao Chen、Ting Ma、Hongjun Liu、Jianmin Wang、Choon-Hong Tan
DOI:10.1002/anie.200903971
日期:2009.9.21
Zero, one, or two? Guanidinium catalyst 1⋅HBArF4 (ArF=3,5‐(CF3)2C6H3, Bn=benzyl, Ts=4‐toluenesulfonyl) was obtained in a single step from a commercially available diamine. By using this catalyst an asymmetric phospha‐Mannich reaction has been developed, involving secondary phosphine oxides and H‐phosphinates as the P nucleophile. A series of enantiomerically enriched α‐amino phosphine oxides (2), α‐amino
Oxidative imination of toluenes catalyzed by Pd–Au/silica gel under mild reaction conditions
作者:Xinjiang Cui、Feng Shi、Youquan Deng
DOI:10.1039/c2cc31438j
日期:——
A PdâAu/SiO2 catalyst was prepared for the oxidative imination of toluenes with up to 99% yields in the absence of dehydrating agents under mild conditions. Nanoparticles with a PdO layer and PdOâAu core may be the active structure for the reaction.