Herstellung von (S)-4-Methyloxetan-2-on(?-Butyrolacton) durch Lactonisierung von (R)-3-Hydroxy-buttersäure mit Orthoessigsäure-triethylester

Abstract

The readily available (R)-3-hydroxybutanoic acid (1) was treated with triethyl orthoacetate, with azeotropic removal of ethanol, to yield (6R)-2-ethoxy-2,6-dimethyl-1,3-dioxan-4-one (3a). Pyrolysis of 3a led to the ?-Lactone of (S)-3-hydroxybutanoic acid and other products. The influence of pressure, temperature, solvents, and some additives has been tested. A procedure for preparing (S)-4-methyloxetan-2-one (4) in a 0.25-mol scale is described.