New Synthesis of Optically Active 5-Isoxazolidinones and β-Amino Acids
摘要:
A new simple and stereoselective synthesis of 5-isoxazolidinones based on the reaction of lithiated 2-isopropyl-2-oxazolines with nitrones is described. A chiral version of such a methodology allows the preparation of highly enantioenriched 5-isoxazolidinones which are useful precursors for the synthesis of beta-amino acids.
Palladium-catalyzed C–H alkenylation of C-aryl N-t-butyl nitrones with ethyl acrylate produced ortho-alkenylated benzamide derivatives via isomerization of the nitrone moiety. The use of 1,1,1,3,3,3-hexafluoro-2-propanol/acetic acid as a solvent resulted in effective C–H alkenylation, while competitive 1,3-dipolar cycloaddition was completely suppressed.
A simple and efficient stereoselective synthesis of polysubstituted beta,gamma-epoxyhydroxylamines and 4-hydroxyalkyl-1,2-oxazetidines, based on the addition of alpha-lithiated aryloxiranes to nitrones and subsequent cyclization of the corresponding intermediates in a 4-exo-tet mode, is described.
Iridium(III)-Catalyzed C–H Amidation of Nitrones with Dioxazolones
作者:Xia Mi、Weisheng Feng、Chao Pi、Xiuling Cui
DOI:10.1021/acs.joc.9b00300
日期:2019.5.3
efficiently achieved through Ir(III)-catalyzed direct C–H amidation of nitrones with good to excellent yields and tolerance of broad functional groups. This reaction smoothly proceeded at roomtemperature in the absence of acid or base in a short reaction time. Carbon dioxide was generated as the sole byproduct, thus providing an environmentally benign amidation process. The title products could be efficiently
Synthesis of Enantiomerically Enriched Oxazolinyl[1,2]Oxazetidines
作者:Renzo Luisi、Vito Capriati、Saverio Florio、Eliana Piccolo
DOI:10.1021/jo035360u
日期:2003.12.1
The first stereoselective synthesis of oxazolinyl[1,2]oxazetidines based on the reaction of lithiated 2-(1-chloroethyl)-2-oxazolines with nitrones is described. Highly enantioenriched oxazolinyl[1,2]oxazetidines have also been prepared starting from a 1:1 diastereomeric mixture of optically active 2-(1-chloroethyl)-2-oxazolines.
Aliphatic nitro compounds chemistry: oximes–nitrones tunable production through directed tandem synthesis
作者:Foad Kazemi、Moosa Ramdar、Jamal Davarpanah
DOI:10.1007/s00706-018-2326-4
日期:2019.2
AbstractReduction of aliphatic nitro compounds in the presence of aldehydes and dialdehydes for tunable directedsynthesis of oximes, nitrones, nitrone–oximes, and dinitrones was reported. The slow and nonselective reduction of aliphatic nitro compounds was directed by condensation of in situ prepared alkylhydroxylamines with aromatic aldehydes. Mononitrones and dinitrones were synthesized at reflux
摘要据报导,在醛和二醛存在下还原脂肪族硝基化合物可调谐合成肟,硝酮,硝酮肟和二硝基酮。脂肪族硝基化合物的缓慢且非选择性的还原是通过原位制备的烷基羟胺与芳族醛的缩合来实现的。在四氢呋喃中,使用SnCl 2 ·2H 2 O和Na 2 CO 3分别在回流和55°C条件下合成单硝酮和二硝酮。研究发现,当使用二醛作为醛源时,催化量的羧酸(如3-苯基丙酸)的存在相对于硝酮肟和二肟而言,可以提高二硝酮的收率。 图形概要