Highly Z‐Selective Synthesis of Highly Substituted 1,3‐Oxathiolane‐2‐imines via TfOH‐Catalyzed Formal [3+2] Cycloaddition of Donor‐Acceptor Oxiranes and Isothiocyanates

• Published in: ChemistrySelect (Weinheim) 2021-04, Vol.6 (13), p.3151-3154
• Main Authors: Zhan, Feng, Wang, Zhe, Wu, Guan‐Zheng, Shi, Zhichao, Zhang, Xun, Zuo, Qinglu, Lin, Jin‐Shun, Jiang, Yuyang
• Format: Article
• Language: English
• Subjects: 1,3-oxathiolane-2-imines; D−A oxiranes; high Z-selectivity; isothiocyanates; TfOH-catalyzed
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.202100637

TfOH‐catalyzed [3+2] cycloaddition of donor‐acceptor oxiranes with isothiocyanates via chemoselective C−O bond breakage of D−A oxiranes was developed under metal‐ and additive‐free conditions. This method providing a facile access to a diverse range of highly substituted 1,3‐oxathiolane‐2‐imines in good to excellent yields and with high Z‐selectivity and excellent functional group tolerance. In addition, the established protocol can be easily scaled up to gram level in excellent yield. Furthermore, transformation of cycloadduct into 1,3‐oxathiolane‐2‐one by acid hydrolysis of the imino group is easily achieved in moderate yield. TfOH‐catalyzed [3+2] cycloaddition of donor‐acceptor oxiranes with isothiocyanates via chemoselective C−O bond breakage of D−A oxiranes was developed, providing a facile access to a diverse range of highly substituted 1,3‐oxathiolane‐2‐imines in good to excellent yields with high Z‐selectivity and remarkable functional group tolerance. Additionally, this protocol can be easily extended to gram level scale in excellent yield and cycloadduct can be converted into 1,3‐oxathiolane‐2‐one.