Three series of substituted1,3,4-oxadiazoles were studied by (17)O NMR spectroscopy. Chemical shifts values were correlated with empirical Hammett parameters as well as calculated bond lengths and chemical shielding values.
An efficient and high yielding Cu-catalyzed direct CâH arylation of azaheterocycles including oxadiazoles, thiadiazoles, benzoxazoles and benzothiazoles has been achieved by employing easily accessible diaryliodonium salts.
Mechanochemical synthesis of 2,5-disubstituted1,3,4-oxadiazoles was developed as an environmentally benign alternative to conventional solvent-based methods. In the presence of triphenylphosphine and trichloroisocyanuric acid, N-acylbenzotriazoles condense with acylhydrazides leading to oxadiazoles derivatives in good to excellent yields within minutes. The approach circumvents the need for strictly
Direct Palladium‐Catalyzed C5‐Arylation of 1,3,4‐Oxadiazoles with Aryl Chlorides Promoted by Bis(di‐isopropylphosphino) Ferrocene
作者:Loris Gelin、Henri Sabbadin、Hélène Cattey、Paul Fleurat‐Lessard、Jean‐Cyrille Hierso、Julien Roger
DOI:10.1002/ejoc.202400212
日期:2024.6.3
The palladium-catalyzed direct arylation of 1,2,4-oxadiazoles proceeds efficiently at low catalyst loading (0.5 to 1 mol %) with the decisive assistance of sterically constrained ferrocenyldiphosphane ligands. This protocol tolerates electron-donating and electron-withdrawing substituents on the (heteroaryl)arylhalide.