Summary A new methyl dimethylene gluconate has been isolated from the sublimate mixture obtained by heating methyl 2, 4: 3, 5-dimethylene-~-gh1conate in vacuo at 130'. The structure of the new diacetal has been shown to be methyl 2, 4: 5, 6-dimethylene-D- gluconate. The rearrangement of a six-membered methylene acetal ring to a fivemembered ring has thus been demonstrated. The application of the procedure of Hudson and Hann ...
