CONVENIENT SYNTHESIS OF GAMMA-ETHOXY-GAMMA-BUTYROLACTONE AND OF SUCCINIC SEMI-ALDEHYDE

Saponification of the diethyl acetal of diethyl formylsuccinate (6) yields the corresponding diacid (7). This compound undergoes a thermal decarboxylation with elimination of ethanol by a concerted mechanism and yields γ-ethoxybutyrolactone (2) via the cyclization of the intermediate γ-ethoxyvinylacetic acid (10). The -γ-ethoxybutyrolactone is a stable protected form of succinic semialdehyde (1) (SSA), allowing its preparation when required. In chloroform solution SSA is in 2 to 1 equilibrium with its γ-hydroxylactone form (ring-chain tautomerism). © 1979, American Chemical Society. All rights reserved.