Synthesis of (sulfodifluoromethyl)phosphonic acid

The Synthesis of Dialkyl α-Halogenated Methylphosphonates

“…127,128 This method is now widely used. 96,[129][130][131][132] The initial reaction involved a 24 hours reflux, but this was recently shortened to one and an half hours with a slight modification in the conditions (refluxing solvent). 99 Other dialkyl bromodifluoromethylphosphonates were obtained in the same way (dimethyl, 55 % 127 ; diisopropyl, 42 % 127 ; dibutyl, 65 % 127 to quantitative yield 95,121 ).…”

“…Firstly, a halogen-metal exchange occurs with cadmium, secondly the so-formed diethoxyphosphinyl difluoromethylcadmium derivative reacts with iodine to give diethyl iododifluoromethylphosphonate in 57 % yield. 97,134,135 The analogous reactions based on halogen-metal exchanges with zinc 131,134,136 or magnesium 99 give up to 70 % and 48 % yields respectively.…”

Preparation of α,α‐difluoromethylene functionalized sulfones

“…The sulfinates 2a or 2b are stable solids at room temperature, but were readily oxidized with hydrogen peroxide to afford the corresponding sulfonates in high yields by 19F NMR analysis [17]. When treated with iodine at room temperature, 2a gave isopropyl iododifluoroacetate.…”

A facile method for the preparation of allylsulphonyldifluoro-acetates and -acetamides

“…The sulphination of perfluoroalkyl iodides with sodium dithionite was first reported by Huang and co-workers and recently, we demonstrated the utility of this methodology in the preparation of the first example of a fluorinated mixed phosphonic/sulphonic acid. 5 We have now found that isopropyl bromodifluoroacetate l a and N,N-diethyl bromodifluoroacetamide l b react with sodium dithionite in the presence of sodium hydrogen carbonate in aqueous acetonitrile at 50 "C isolated yields, respectively. In the presence of a catalytic amount of cuprous bromide, reaction of 2 with allyl bromide in DMF at 40 "C gave allylsulphonyldifluoro-acetate 3a or -acetamide 3b in good yields.…”