Electrochemical Direct Thiolation of Lactams with Mercaptans: An Efficient Access to N‐Acylsulfenamides

• Published in: European journal of organic chemistry Vol. 2021; no. 33; pp. 4728 - 4732
• Main Authors: Wei, Zhaoxin, Wang, Renjie, Zhang, Yonghong, Wang, Bin, Xia, Yu, Abdukader, Ablimit, Xue, Fei, Jin, Weiwei, Liu, Chenjiang
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 07.09.2021; Wiley Subscription Services, Inc
• Subjects: Chemical reactions; Chemistry; Chemistry, Organic; Cross coupling; Free radicals; Hydrogen evolution; Lactams; Mercaptans; N-acylsulfenamides; N−S bonds; Oxidizing agents; Physical Sciences; Science & Technology; Thiolation; Thiols; ELECTROSYNTHESIS; OXIDATION; Mercaptans; CHEMISTRY; Lactams; N-acylsulfenamides; BOND FORMATION; N-S bonds; Thiolation; AMIDES
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.202100924

An efficient and eco‐friendly electrochemical methodology for the oxidative cross coupling hydrogen evolution (CCHE) reactions of lactams with thiols is presented. Various electron deficient N‐acylsulfenamides are smoothly produced in modest to excellent yields without using any external oxidant. Elementary mechanistic insight supports a possible free radical process and hydrogen is the only side product. This approach provides a safe, convenient, and economical preparation of synthetically important N‐thiophthalimides on a gram scale. A variety of N‐acylsulfenamides are produced by the electrochemically enabled cross‐coupling of readily available feedstocks under standard conditions. This protocol is practical and has wide substrate scope with good reaction efficiency (38 examples, up to 97 % yield). A possible free radical mechanism is preliminarily demonstrated.