A Practical Approach to Ureas and Thiocarbamates: SO2F2‐Promoted Lossen Rearrangement of Hydroxamic Acid. Issue 26 (9th July 2020)

• Record Type: Journal Article
• Authors: Zhang, Guofu; Cui, Yin; Zhao, Yiyong; Cui, Yunqiang; Bao, Shenxiao; Ding, Chengrong
• Is Part Of: ChemistrySelect. Volume 5:Issue 26(2020)
• Page Start: 7817
• Page End: 7821
• Publication Date: 2020-07-09
• Subjects: Rearrangement -- Sulfuryl fluoride -- Synthetic methods -- Thiocarbamates -- Ureas; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.202002270
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: In this update, we report a simple, mild and practical method for the synthesis of symmetrical urea via Lossen rearrangement promoted by SO2 F2, which achieves the conversion from hydroxamic acid to symmetrical urea in high selectivity and provides a new method for facile initiation of Lossen rearrangement. Meanwhile, the reaction within amine or thiol also provide the efficient synthetic strategy towards unsymmetrical urea or thiocarbamates. Significant for gram‐scale application, we afford the desired product on gram‐scale by filtration without further purification. A plausible mechanism which is supported by control experimental and spectral data is proposed. Abstract : We have developed a mild and practical method for the straightforward construction of symmetrical urea from hydroxamic acid via SO2 F2 ‐promoted Lossen rearrangement. And the SO2 F2 ‐promoted Lossen rearrangement could be extended to the synthesis of unsymmetrical urea and thiocarbamates with good compatibility of substrate. This reaction is characterized by its mild lowest total organic carbon, carbonless promoter, mild conditions, good yields and easy scale‐up to 10 g products. A tentative mechanism for SO2 F2 ‐promoted Lossen rearrangemen was proposed.