Stereoselective Synthesis of Novel 4,5-Epoxy-1,2-oxazin-6-ones and α,β-Epoxy-γ-amino Acids from β-Lithiated Oxazolinyloxiranes and Nitrones
摘要:
A stereoselective synthesis of 9,10-epoxy-1,6-dioxa-4,7-diazaspiro[4,5] decanes has been developed on the basis of the addition of beta-lithiated oxazolinyloxiranes to nitrones. Conversion of these spirocyclic derivatives into 4,5-epoxy-1,2-oxazin-6-ones and successively into alpha,beta-epoxy-amino gamma- acids, alpha-hydroxy-gamma-amino acids, and gamma-butyrolactams is described.
作者:Jonathan T. Reeves、Chris Lorenc、Kaddy Camara、Zhibin Li、Heewon Lee、Carl A. Busacca、Chris H. Senanayake
DOI:10.1021/jo500848a
日期:2014.6.20
The addition of carbamoyl anions derivedfrom N,N-disubstituted formamides and LDA to N-tert-butyl nitrones is described. The reaction was demonstrated with a variety of formamides and nitrones and provided a direct route to α-(N-hydroxy)amino amides. The use of a tert-leucinol derivedchiralauxiliary on the nitrone provided products in good diastereoselectivity. Derivatization of the products by
Transition Metal-Free TEMPO-Catalyzed Oxidative Cross- Coupling of Nitrones with Alkynyl-Grignard Reagents
作者:Sandip Murarka、Armido Studer
DOI:10.1002/adsc.201100327
日期:2011.10
cross-coupling of nitrones and alkynyl-magnesium compounds using a catalytic amount of 2,2,6,6-tetramethylpiperidine-N-oxyl radical (TEMPO) as an environmentally benign organic oxidant and dioxygen as terminal oxidant is described. These coupling reactions can be performed without adding any transition metal on various N-tert-butylnitrones and alkynyl-Grignardreagents. Moreover, the alkynylated nitrone products
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.
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.