Silver-catalyzed stereoselective C-4 arylthiodifluoromethylation of coumarin-3-carboxylic acids via a double decarboxylative strategy

A facile silver-catalyzed dual decarboxylation of arylthio-difluoroacetic acid with coumarin-3-carboxylic acids/chromone-3-carboxylic acids was developed. This method provided a unique way to synthesize a series of C-4 arylthiodifluoromethylated 3,4-dihydrcoumarins/C-2 arylthiodifluoromethylated chromanones...

Evidence for the Formation of Difluoroacetic Acid in Chlorofluorocarbon-Contaminated Ground Water

The concentrations of difluoroacetic acid (DFA) and trifluoroacetic acid (TFA) in rainwater and surface water from Berlin, Germany resembled those reported for similar urban areas, and the TFA/DFA ratio in rainwater of 10:1 was in accordance with the literature. In contrast, nearby ground water historically contaminated with 1,1,2-trichloro-1,2,2-trifluoroethane (R113) displayed a TFA/DFA ratio of 1:3. This observation is discussed versus the inventory of microbial degradation products present in this ground water along with the parent R113 itself. A microbial transformation of chlorotrifluoroethylene (R1113) to DFA so far has not been reported for environmental media, and is suggested based on well-established mammalian metabolic pathways.

Transition-Metal-Free Efficient Synthesis of Bisindole Sulfanes Using 2-(Fluorosulfonyl)difluoroacetic Acid

By using 2-(fluorosulfonyl)difluoroacetic acid as sulfur ­reagent, bisindole sulfanes were highly efficient synthesized under transition-metal-free conditions. Results indicate that this proceeded not at the relatively acidic C-2 position but rather selectively at the nucleo­philic C-3 position to give the desired compounds with excellent regio­selectivities and good yields.