Brønsted Base-Catalyzed Umpolung Intramolecular Cyclization of Alkynyl Imines
作者:Azusa Kondoh、Masahiro Terada
DOI:10.1002/chem.201800219
日期:2018.3.15
A novel “umpolung” intramolecular cyclization of alkynyl imines, in which the electrophilic imine sp2‐carbon formally serves as a nucleophilic site, was developed under Brønsted base catalysis. The reaction involves the unprecedented catalytic generation of α‐aminoester enolates from α‐iminoesters via the 1,2‐addition of the anion of a secondary phosphite to an imine moiety followed by the [1,2]‐rearrangement
Diastereoselective synthesis of α-dicarbonyl cyclopropanes <i>via</i> a lanthanide amide-catalysed reaction
作者:Wenxi Sun、Cheng Peng、Zhigang Yao、Fan Xu
DOI:10.1039/c9ob00732f
日期:——
as efficient catalysts for a one-pot reaction of α-ketoesters, dialkyl phosphite, and activated alkenes to produce α-dicarbonyl cyclopropanes in moderate to high yields. The reaction was stereoselective and the two adjacent carbonyls linked to the cyclopropane were in the cis-configuration. The high efficiency of the lanthanide amide in catalysing the reaction is the result of the cooperation between
Organocatalytic Arylation of α-Ketoesters Based on Umpolung Strategy: Phosphazene-Catalyzed S<sub>N</sub>
Ar Reaction Utilizing [1,2]-Phospha-Brook Rearrangement
作者:Azusa Kondoh、Takuma Aoki、Masahiro Terada
DOI:10.1002/chem.201803218
日期:2018.9.6
three‐component couplingreaction of α‐ketoesters, a silylated secondary phosphite, and electron‐deficient fluoroarenes to provide α‐hydroxyester derivatives possessing an electron‐deficient arylgroup at the α‐position. The reaction involves the catalytic generation of α‐oxygenated ester enolates from α‐ketoesters through the [1,2]‐phospha‐Brook rearrangement followed by the SNAr reaction.
α-酮酸酯的有机催化芳基化反应是基于umpolung策略开发的。磷腈P2- t Bu有效催化α-酮酸酯,甲硅烷基化的亚磷酸酯和缺电子的氟代芳烃的三组分偶联反应,从而提供在α-位置具有缺电子的芳基的α-羟基酯衍生物。该反应涉及通过[1,2]-磷-布鲁克重排反应,由α-酮酸酯催化生成α-氧化酯烯酸酯,然后进行S N Ar反应。
Lee, Koo; Wiemer, David F., Phosphorus, Sulfur and Silicon and the Related Elements, 1993, vol. 75, # 1-4, p. 87 - 90