1976 年 25 巻 6 号 p. 326-328
A convenient synthesis of 3-methyl-2-cyclopenten-2-ol-1-one (IIIa), a constituent of coffee aroma and maple flavor, is described. Condensation of diethyl glutarate with diethyl oxalate in N, N-dimethylformamide gave diketodiester I ; methylation in methyl ethyl ketone or in acetonitrile in the presence of potassium carbonate produced doubly methylated compound IIa which was hydrolyzed and decarboxylated to afford IIIa by refluxing with concentrated hydrochloric acid in acetic acid. Other allied compounds were also synthesized.