Trimethylsilyl fluorosulfonyldifluoroacetate (TFDA): a new, highly efficient difluorocarbene reagent

Metal-free synthesis of α,α-difluorocyclopentanone derivatives via regioselective difluorocyclopropanation/VCP rearrangement of silyl dienol ethers

“…Trimethylsilyl 2,2-difluoro-2-(fluorosulfonyl)acetate (TFDA) was prepared according to the literature. 13 All of silyl dienol ethers (starting materials) 1a-j were prepared according to the literature 7,17 and the spectral data were in good agreement with those in the literature. 7,17 1,8-Bis(dimethylamino)naphthalene (proton sponge) and 1,1,1,3,3,3-hexafluoro-2,2-di(p-tolyl)propane (internal standard for 19 F NMR) was purchased from Tokyo Chemical Industry Co., Ltd. Proton sponge was recrystalized from methanol/water.…”

“…Recently, we have also developed an organocatalytic method for the generation of difluorocarbene by the decomposition of trimethylsilyl 2,2-difluoro-2-(fluorosulfonyl)acetate (TFDA) [11][12][13] (Scheme 2). [14][15][16][17] The compound 1,8-bis(dimethylamino)naphthalene (proton sponge) was an efficient catalyst for the generation of difluorocarbene, with which silyl dienol ethers were chemoselectively transformed to the corresponding difluoro(vinyl)cyclopropanes, leading to the generation of α-fluorocyclopentenones via a fluorine-directed and -activated Nazarov cyclization (Scheme 3, Path A).…”

A new synthesis of 2-fluoro-1-naphthols

“…Recently, we reported the sequential reaction of aryl alkyl ketones with two equivalents of difluorocarbene, generated thermally (under fluoride catalysis) from acid free trimethylsilyl fluorosulfonyldifluoroacetate (TFDA) [10], to form difluoromethyl 2,2-difluorocyclopropyl ethers, via the intermediate formation of difluoromethyl enol ethers (Scheme 3) [11].…”

“…FSO 2 CF 2 COOSiMe 3 (TFDA) was prepared according to the literature [10]. Sodium fluoride (NaF) was oven dried before use.…”

Organocatalytic, difluorocarbene-based S-difluoromethylation of thiocarbonyl compounds

“…When trimethylsilyl 2,2-difluoro-2-fluorosulfonylacetate (TFDA) [22] was treated with a catalytic amount of N-heterocyclic carbene (NHC) [23] at 80-100 8C, decomposition of TFDA smoothly proceeded under nearly neutral conditions to generate difluorocarbene. Ketones and secondary amides underwent selective difluoromethylation on the carbonyl oxygens with the electrophilic carbene thus generated, which afforded difluoromethyl vinyl ethers [21a] and difluoromethyl imidates [21b] in high yields, respectively.…”