Visible-Light-Induced DDQ-Catalyzed Fluorocarbamoylation Using CF₃SO₂Na and Oxygen

eFluorination for the Rapid Synthesis of Carbamoyl Fluorides from Oxamic Acids

“…Fluorine has long held a special place in many areas of chemistry as a result of its ability to impart or enhance remarkable physical and chemical properties to a molecule when present in its framework. − Carbamoyl fluorides have attracted much attention for their use as insecticides and esterase inhibitors. − In addition, because carbamoyl fluorides exhibit greater stability and selectivity than carbamoyl chlorides, they represent exceptional building blocks in the synthesis of hydrazines, isocyanates, carbamates, thiocarbamates, ureas, and amides. − ,, Unfortunately, their synthesis can remain a challenge (Figure ). , The primary preparation method is to treat a carbamoyl chloride with nucleophilic sources of fluoride. , While this method seems straightforward, it still requires the preparation of the highly reactive and often unstable chloride analogue, which is usually produced using expensive and highly toxic phosgene derivatives. , The past decade has seen a rapid increase in the development of novel methods for preparing carbamoyl fluorides, confirming the growing interest of the synthetic community in this fluorinated motif. − However, most use impractical conditions, often combined with highly air- and water-sensitive, toxic, hazardous, and expensive reagents, such as carbonyl difluoride, ,− carbon disulfide, highly reactive and unstable carbamoyl chlorides, or explosive diethylaminosulfur trifluoride (DAST)-type reagents. , Some other methods need expensive Ag salts, significant excess of reagents leading to time-consuming chromatographic purifications, , or high temperatures . Although some early work has yielded the desired products in single-step reactions, using DAST and silver salts presents a significant challenge to scale up the reaction, especially under process-friendly conditions. ,− There is an urgent need to develop a novel, practical, sustainable, inexpensive, and milder way to access carbamoyl fluorides rapidly.…”

“… 21 − 24 However, most use impractical conditions, often combined with highly air- and water-sensitive, toxic, hazardous, and expensive reagents, such as carbonyl difluoride, 13 , 25 − 28 carbon disulfide, 29 highly reactive and unstable carbamoyl chlorides, 28 or explosive diethylaminosulfur trifluoride (DAST)-type reagents. 30 , 31 Some other methods need expensive Ag salts, 32 significant excess of reagents leading to time-consuming chromatographic purifications, 33 , 34 or high temperatures. 35 Although some early work has yielded the desired products in single-step reactions, using DAST and silver salts presents a significant challenge to scale up the reaction, especially under process-friendly conditions.…”