chromatography (HPLC) and ESR spectrometry was used to isolate the radical products obtained by photolysis of o‐methylbenzaldehyde (1), o‐methylacetophenone (2) and o‐methylbenzophenone (3) in the presence of α‐phenyl‐N‐tert‐butylnitrone and its derivatives (4–19). Linear correlations between the hyperfine splitting constants and the Hammett parameters are observed. The mass spectra of the HPLC–ESR isolated
Addition of Silyl Ketene Acetals to Nitrones Catalyzed by Lanthanide Triflates
作者:Changtao Qian、Longcheng Wang
DOI:10.1016/s0040-4020(00)00636-0
日期:2000.9
α-Aryl-N-phenyl nitrones reacted with silyl ketene acetals mediated by lanthanum trifloromethanesulfonate (triflate) to afford the addition product in excellent yield under mild conditions. α-Aryl-N-tert-butyl nitrone reacted with ethyl trimethylsilylacetate to yield the unexpected α,β-unsaturated ester in a 100% E-form. A possible mechanism for the process is discussed.
Borrowing and Returning Oxygen Atom in Trifluoroacetic Anhydride Transfer to Nitrones: A Versatile Route for the Synthesis of <i>N</i>
-Trifluoroacetyl Amides
作者:Junwen Wang、Zhiqiang Weng
DOI:10.1002/ejoc.201801662
日期:2019.2.14
A variety of N‐trifluoroacetyl amides are obtained from trifluoroaceticanhydride transfers to nitrones through borrowing and returning oxygen atom. This transformation proceeds smoothly under mild conditions via electrophilic trifluoroacetylation, followed by nucleophilicaddition and elimination, and intramolecular substitution. Furthermore, the method also provides efficient access to N‐difluoroacetyl
Access to Indenones by Rhodium(III)-Catalyzed C–H Annulation of Arylnitrones with Internal Alkynes
作者:Zisong Qi、Mei Wang、Xingwei Li
DOI:10.1021/ol4025309
日期:2013.11
Under redox-neutral conditions, rhodium(III)-catalyzed C–H annulation of N-tert-butyl-α-arylnitrones with internal alkynes has been realized for the synthesis of indenones under mild conditions. This reaction proceeded in moderate to high yields and with good functional group tolerance.
Dual Role of Pyrrolidine and Cooperative Pyrrolidine/Pyrrolidinium Effect in Nitrone Formation
作者:Sara Morales、Fernando G. Guijarro、Inés Alonso、José Luis García Ruano、M. Belén Cid
DOI:10.1021/acscatal.5b01726
日期:2016.1.4
The formation of nitrones by direct condensation between equimolecular amounts of N-substituted hydroxylaminehydrochlorides and aromatic or aliphatic aldehydes is efficiently promoted by pyrrolidine in a matter of minutes under very mild conditions in almost quantitative yields after a simple filtration through a short pad of silica gel. According to theoretical, spectroscopic, and experimental studies