Electrolytic Partial Fluorination of Organic Compounds. 35.1 Anodic Fluorination of 2-Pyrimidyl, 2-Pyridyl, and 2-Quinazolinonyl Sulfides
摘要:
Highly regioselective electrochemical fluorination of 2-pyrimidyl sulfides having an electron(EWG) withdrawing group at the position alpha to the sulfur atom was successfully carried out using Et4NF . nHF (n = 3, 4) or Et3N . 3HF as a supporting electrolyte and a fluoride ion source in 1,2-dimethoxyethane (DME) in an undivided cell. 2-Methylthiopyrimidine devoid of an EWG was also selectively fluorinated in DME to provide 2-(fluoromethylthio)pyrimidine in a moderate yield as 63%, while corresponding 2-methylthiopyridine was less selectively fluorinated in lower yield along with alpha,alpha-difluorinated product. In contrast, the corresponding 2-quinazolinonyl sulfides underwent similarly alpha-fluorination along with unexpected ipso-fluorination through anodic desulfurization.