H. Abdelrahman et al., SYNTHESIS OF A NOVEL SPIROCYCLIC LACTONE IN A POTENTIAL ROUTE TO SQUALESTATIN-1, Journal of the Chemical Society. Perkin transactions. I, (10), 1994, pp. 1259-1261
The isomeric butenolides 1 and 2 have been converted into the spiro-la
ctone derivative 20 via sequential ring contraction-rearrangement proc
esses. X-Ray crystal data have been obtained on compound 12b.