Collect. Czech. Chem. Commun. 1982, 47, 3418-3423

Synthetic transformations of dimethyl perfluoro-4-methyl-2-pentenedioate

Jiří Svoboda, Oldřich Paleta and Václav Dědek

Department of Organic Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6


Reaction of the title compound I with methanolic sodium methoxide proceeded with decarboxylation and substitution of the vinylic fluorine atom, the resulting product being methyl 2,4,5,5,5-pentafluoro-3-methoxy-2-pentenoate (II). Compound I reacted with chlorine to give dimethyl 2,3-dichloro-2,3,4-trifluoro-4-trifluoromethylpentanedioate (III) which was selectively hydrolyzed to potassium 1-methyl 2,3-dichloro-2,3,4-trifluoro-4-trifluoromethylpentanedioate (IV). This ester salt was transformed in two steps into methyl 2,3-dichloro-4-fluoroformylhexafluoropentanoate (VIII). Pyrolysis of IV afforded methyl 2-chlorohexafluoro-3-pentanoate (V). Reduction of the diester III with sodium borohydride led to 3-chloro-2,3,4-trifluoro-2-hydroxymethyl-4-trifluoromethyloxolane (IX) and 2,3-dichloro-2,3,4-trifluoro-4-trifluoromethyl-1,5-pentane diol (X).