Modern synthesis of carbamoyl fluorides

Synthesis of Carbamoyl Fluorides via a Selective Fluorinative Beckmann Fragmentation

“…While development of new methods had not attracted attention for a long time, a handful of alternative methods were recently reported (Scheme a) . For instance, a unique reaction employing difluorocarbene precursors and hydroxylamine substrates was discovered by Bolm et al.…”

Oxidation of Difluorocarbene by Pyridine N‐Oxide and Ensuing Access to Carbamoyl Fluorides†

“…[ 9 ] Therefore, the preparation of carbamoyl fluoride has gained extensive attention from synthetic community. [ 10 ] Previous approaches for the assembly of this motif include halogen exchange between carbamoyl chloride and fluoride salts, [ 11 ] a mixture of secondary amines to the toxic and gaseous difluorophosgene (COF 2 ) or reagents that liberate COF 2 in situ , [ 9c,12 ] and some COF 2 ‐free methods. [ 13 ] However, the high toxicity, no ease to obtain and handle of COF 2 have extremely limited its wide application in the synthesis of carbamoyl fluoride.…”

Synthesis of Fluorinated Amines: A Personal Account

“…The synthesis of carbamoyl fluorides has attracted much attention these last five years due to the increased stability of such a motif in comparison to other halogenated analogues. − However, historical synthetic strategies were mainly based on the use of toxic difluorophosgene derivatives. − More friendly alternatives were since developed relying on the in situ generation of difluorophosgene from a trifluoromethoxy anion − or the use of PDFA as a difluorocarbene source in the presence of an oxidant (Scheme ). It should also be mentioned that other starting materials were used for the synthesis of carbamoyl fluorides including hydroxylamine derivatives. − …”