Enantioselective Synthesis of 4-Isoxazolines by 1,3-Dipolar Cycloadditions of Nitrones to Alkynals Catalyzed by Fluorodiphenylmethylpyrrolidines
作者:José Alemán、Alberto Fraile、Leyre Marzo、José Luis García Ruano、Cristina Izquierdo、Sergio Díaz-Tendero
DOI:10.1002/adsc.201200033
日期:2012.6.18
The first organocatalytic enantioselective 1,3‐dipolar reaction between nitrones and alkynalscatalyzed by (S)‐2‐(fluorodiphenylmethyl)pyrrolidine to give 4‐isoxazolines (2,3‐dihydroisoxazoles) with high enantiomeric excess, excellent yields and low catalyst loading (1–5 mol%) is presented. The catalytic loading could be reduced to 1 mol% with only slight increases in reaction times.
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.