Butyrolactones oxidative degradation

While ethers react only slowly with dimethyldioxirane, they are efficiently hydroxylated by methyl(trifluoromethyl)dioxirane even at low temperatures. Thus r-butyl methyl ether [32] was converted to f-butyl alcohol through its hemiacetal. On the other hand, tetrahydrofuran gave butyrolactone [32] in which presumably the intermediary cyclic hemiacetal was oxidized to the lactone by an additional C —H insertion. The ketal was degraded into 2-butanone and the orthoformate into diethyl carbonate [32]. The latter transformation may serve useful for deketalation under neutral conditions. 

As it is known that a cyclic ether (THE) may be formed during degradation and from the 1,4-butanediol by-product, the 1,4-diacid and hydroxyacids noted above could therefore also cyclise, leading to formation of succinic anhydride and y-butyrolactone. Further studies are required to investigate if any of these possible products occur in the thermo-oxidation of PBT. 

---