Sodium salt, sulfonates and carboxylates of (E)- and (Z)-3-(hydroxymethylene)-5-methyldihydro-2(3H)-furanone

Abstract

In the solid state, sodium salt of 3-(hydroxymethylene)-5-methyldihydro-2(3H)-furanone can be prepared in the form of the (Z)-isomer, (E)-isomer or as a mixture of both isomers; in solutions the salt exists exclusively as the (E)-isomer. Reaction of the corresponding isomers of this sodium salt with sulfonyl or acyl chlorides afforded sulfonates or carboxylates derived from (E)- or (Z)-3-(hydroxymethylene)-5-methyldihydro-2(3H)-furanone. Configurations of the obtained isomeric sulfonates and carboxylates were confirmed by their 1H and 13C NMR spectra. Dihedral angles, calculated from the observed coupling constants, were used in the discussion of preferred conformation of the prepared compounds.