Access to α,α-dihaloacetophenones through anodic CC bond cleavage in enaminones

• Published in: Tetrahedron letters Vol. 88
• Main Authors: Zhang, Zhenlei, Yang, Jiusi, Wu, Kairui, Yu, Renjie, Bu, Jiping, Huang, Zijun, Li, Shaoke, Ma, Xiantao
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 05.01.2022
• Subjects: Electrosynthesis; Green chemistry; N,N-Dimethyl enaminone; α,α-Dihaloacetophenones; Electrosynthesis; N,N-Dimethyl enaminone; Green chemistry; α,α-Dihaloacetophenones
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/j.tetlet.2021.153575

A novel electrochemical strategy for the efficient synthesis of α,α-dihaloacetophenone derivatives from N,N-dimethyl enaminones was reported, which was performed under constant current conditions in a simple undivided cell using HCl or HBr as halide source and supporting electrolyte. [Display omitted] We have developed a method to synthesize α,α-dihaloketones under electrochemical conditions. In this reaction, the Cl- or Br- is oxidized to Cl2 or Br2 at the anode, which undergoes two-step addition reactions with the N,N-dimethyl enaminone, and finally breaks CC of the N,N-dimethyl enaminone to generate α,α-dihaloketones. The electrosynthesis reaction can be conveniently carried out in an undivided electrolytic cell at room temperature. In addition, various functional groups are compatible with this green protocol which can be applied simultaneously to the gram scale without significantly lower yield.