One-pot carbonylation-dehydration tandem reaction of aryl iodides with acylhydrazines for synthesis of 2,5-diaryl-1,3,4-oxadiazoles

作者：Guo, Lin; Yang, Shu-Qing; Zhao, Kai-Chun; Chen, Xiao-Chao; Lu, Yong; Liu, Ye^*

来源：Monatshefte für Chemie, 2023, 154(2): 215-222.

DOI：10.1007/s00706-022-03021-8

• Carbonylation
• Dehydration
• Aminocarbonylation
• Tandem reaction
• Oxadiazoles

The structures of 2,5-diaryl-1,3,4-oxadiazoles with good stability have attract great attention for development of new and safe therapeutic agents with functions in antimicrobial, anti-inflammatory, antitumor, and antiviral (for treatment of HIV infection), etc. In the present work, over the developed Pd-catalytic system with involvement of the 3-thiophenyl-benzimidazolyl-based mono-phosphine, the one-pot carbonylation-dehydration tandem reaction of aryl iodides with acylhydrazines for synthesis of 2,5-diaryl-1,3,4-oxadiazoles was reported for the first time with advantages of simplified manipulations, high efficiency (yields of 62-93%), as well as high safety of applied organic substrates. The relatively high reaction temperature of 140-160 ? was required for this tandem reaction, wherein the good stability of the involved phosphine with suitable stereo-electronic property guaranteed the fulfilment of this sequence. It was demonstrated that the first-step carbonylation of aryl iodides with acylhydrazine toward N,N '-diarylhydrazides was the rate-determine step in the overall process. Subsequently, the formed N,N'-dibenzoylhydrazides irreversible dehydrated into 2,5-diaryl-1,3,4-oxadiazoles with the presence of dehydrating agent like DCC.[Graphical Abstract]

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