Preparation and regioselective reactions of novel gem-difluorinated vinyloxiranes with some organometallic reagents.
Hitherto unknown, relatively labile gem-difluorinated vinyloxiranes were prepared by difluoro-Wittig reactions with alpha,beta-epoxyketones; for these vinyloxiranes alkyl groups were delivered at the fluorine-attached terminal carbon atom in an SN2' manner by RLi, while Me3Al and MeMgBr-CuCl (3: 1) introduced the Me group at the allylic epoxy carbon with retention and inversion of the original stereochemistry, respectively.
A new route to 1,1-difluoroolefins
Abstract A new method for the synthesis of various 1,1-difluoroolefins is described. The key step is the treatment of 1-bromo-1,1-difluoro-2-alkenes with organo-metallic reagents in the presence of copper and lithium salts.
Réaction de CF2CH2 Avec less organolithiens une nouvelle preparation du difluorovinyllithium
Abstract 2,2-Difluorovinyllithium has been prepared in quantitative yield from CF2CH2 and sec.butyllithium at low temperature. Reaction of 2,2-difluorovinyllithium with carbonyl groups gives the corresponding alcohols.