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.
Fluorinated succinic acid derivatives from new refrigerants via ozonolysis of haloalkenes
Fluoro- and di-fluoro allylic alcohols obtained from HFC-134a and HCFC-133a were transformed through [3,3]-sigmatropic rearrangements into 3-fluoro-4-halo-4-alkenoates with variable substitution at the 2- and 3-positions. Ozonolysis of the haloalkenes afforded the corresponding acyl halides which could be trapped with nucleophiles to afford fluorinated succinic acid derivatives in which the two carboxylic acid groups were differentiated.
Solid phase synthesis of ketones from esters
Abstract A one-pot procedure for the solid phase synthesis of ketones from the corresponding esters, via in situ formation of the N-methoxy-N-methylamide, is described.