Method for preparing cyano sulfonyl fluoride compounds

A method for preparing cyano sulfonyl fluoride compounds comprises following steps:

• in an organic solvent, using oxime ether compounds as free radical precursors, and in a protective atmosphere, adding photocatalyst, sulfur dioxide source and organic base free radical initiator, and stirring a mixture under an illumination condition to allow the oxime ether compounds to subject to photocatalytic oxidation and reduction to generate nitrogen free radicals, and followed by C—C bond cleavage rings and free radical SO2 insertion;
• subsequently, adding fluorine source to undergo fluorination, and achieving cyano/fluorosulfonyl reaction of oxime ether to obtain the cyano sulfonyl fluoride compounds;
• wherein a general reaction formula is as follows:
• wherein R is one of hydrogen, alkyl, aryl, ester group and heterocyclic ring, X is one of carbon, oxygen and sulfur, n is one of 1, 2 and 3, and the sulfur dioxide source is 1,4-diazabicyclo[2.2.2] octane-1,4-dium-1,4-disulfonic acid;
• and
• the fluorine source is a selective fluorine reagent, the sulfur dioxide source is DABSO, the organic base free radical initiator is tetramethylguanidine, the organic solvent is dichloroethane, the photocatalyst is 4CzIPN, Eosin Y, TPT, Mes-Acr-Me-ClO4 or Mes-(t-Bu)2Acr-Ph-BF4, and photocatalytic irradiation wavelength is 460 nm.