Free-radical chemistry

An Efficient Synthesis of 1-chloro-2,2-difluoroethylene via the Reductive Dechlorination of 1,2,2-trichloro-1,1-difluoroethane

1-Chloro-2,2-difluoroethylene was prepared from 1,2,2-trichloro-1,1-difluoroethane by reductive dechlorination in the presence of zero-valent zinc. Eleven different solvents were investigated and the best results were obtained in methanol, dimethyl formamide and ethanol at 80 °C. A large-scale experiment using ethanol as a solvent gave 1-chloro-2,2-difluoroethylene in high yield. These results provide a method for producing 1-chloro-2,2-difluoroethylen e on an industrial scale because 1,2,2-trichloro-1,1-difluoroethane is the waste material arising from 2,2-dichloro-1,1,1-trifluoroethane production. These results can also provide a method for solving the recycling problem of 1,2,2-trichloro-1,1-difluoroethane in 2,2-dichloro-1,1,1-trifluoroethane production.

A vicarious one-pot transformation of a fluorocyclitol to a polycyclitol: observation of a formal 4-fold axial-equatorial epimerization on a conformationally locked scaffold

A conformationally locked fluoropentol undergoes an interesting transformation to (trans,anti,trans,anti,trans)-perhydro-2,3,4a,6,7,8a-naphthalenehexol essentially under conditions of base-induced transesterification. The proposed rationale for the observed metamorphosis involves a nucleophilic displacement of fluoride, and subsequent stereo- and regioselective anti-Fürst-Plattner-type ring-opening of the epoxide thus formed.