An efficient iodine-mediatedoxidation reaction for ynamides has been developed to produce N-monosubstituted α-ketoamides and α-ketoimides. This oxidative method, which exhibits good functional group tolerance, was performed under mild conditions without a metal catalyst.
Preparation of 3,4,5-Trisubstituted Oxazolones by Pd-Catalyzed Coupling of <i>N</i>-Alkynyl <i>tert</i>-Butyloxycarbamates with Aryl Halides and Related Electrophiles
oxazolones has been achieved by the coupling of N-alkynyl tert-butyloxycarbamates with aryl halides and related electrophiles, which involves an oxidative addition followed by oxypalladation/reductive elimination. The reaction provides a convenient access to diversely substituted oxazolones in satisfactory yields and shows good functional group compatibility.
PhI(OAc)<sub>2</sub>-mediated trifluoromethylthiolation/oxidative cyclization of ynamides
作者:Shixuan Su、Zhipeng Yan、Xingyuan Ye、Jingyang Wang、Yuan Li、Guangke He
DOI:10.1039/d1ob01642c
日期:——
A PhI(OAc)2-mediated trifluoromethylthiolation/oxidative cyclization of ynamides with the Shen reagent has been established herein, providing a facileaccess to CF3S-substituted oxazolidine-2,4-diones bearing a quaternary carbon center in 38–85% yields with chemoselectivities of up to 99/1.
Using cheap and readily accessible CuCl as the catalyst, an operationally simple and efficient method for the synthesis of 3,5-disubstituted oxazolones has been realized by the cyclization of N-alkynyl tert-butyl carbamates. The reaction proceeds under mild reaction conditions and shows good functional group compatibility.
A mild and operationally simple approach to highly functionalized oxazolones has been developed, which involves an intramolecular oxypalladation of N-alkynyl tert-butyloxycarbamates, followed by either protonolysis of the alkenyl C-Pd bond to afford 3,5-disubstituted oxazolones or allylation with allyl halides in the presence of Ag2CO3 to generate 3,4,5-trisubstituted oxazolones, respectively. (C) 2012 Elsevier Ltd. All rights reserved.