1660-56-6Relevant academic research and scientific papers
COMBINED HALOGENATION OF UNSATURATED COMPOUNDS. XV. SYNTHESIS OF DIASTEREOMERIC PAIRS OF 2,3-DICHLORO-3-FLUOROISOBUTYRIC, 2,3-DICHLORO-2,3-DIFLUOROPROPIONIC, AND 2,3-DIHALOGENO-3-FLUOROBUTYRIC ESTERS AND INVESTIGATION OF SOME OF THEIR ELIMINATION REACTIONS
Boguslavskaya, L. S.,Chernov, A. N.,Krom, E. N.
, p. 1392 - 1397 (2007/10/02)
The selective inversion of the configuration of methyl 2R,3R-2,3-dichloro-3-fluoroisobutyrate and 2R,3R-2,3-dichloro-2,3-difluoropropionate to their 2R,3S-diastereomers was realized by dechlorination and subsequent catalytic chlorination of the obtained methyl E-β-fluoro-α-methylacrylate and Z-α,β-difluoroacrylate, respectively.The chlorofluorination and bromofluorination of E- and Z-ethyl β-chlorocrotonates by hexachloromelamine and N-bromosuccinimide in liquid hydrogen fluoride were investigated.The reactions are regioselective and nonstereospecific and lead to the formation of a mixture of ethyl 2R,3R- and 2S,3R-2,3-dichloro-3-fluorobutyrates and 2-bromo-3-chloro-3-fluorobutyrates, respectively.The individual diastereomers were isolated, and the dechlorination and dehydrochlorination of the diastereomeric ethyl 2,3-dichloro-3-fluorobutyrates were investigated.Preparative methods are proposed for the synthesis of E- and Z-ethyl β-fluorocrotonates and Z-ethyl α-chloro-β-fluorocrotonate.
