STUDIES ON THE DEGRADATION OF MEVINOLIN AND COMPACTIN - A FORMAL ROUTE TO SEMISYNTHETIC ANALOGS

Procedures are described for degrading mevinolin (1a) and compactin (1b) into the enone 2, which is a substance that has been elaborated into 1a, 1b, and 3-ethylcompactin (1c). Consequently, 2 serves as an advanced intermediate for the construction of semisynthetic analogues of the mevinic acids. The degradation is based largely on a series of oxidations (epoxidation of allylic and homoallylic double bonds, alpha-hydroxylation of a ketone unit) and on S(N)2' addition of phenyldimethylsilyl cuprates to a vinyl epoxide system). These reactions are applied in a way that leads to 33 and 50, which are then cleaved with Pb(OAc)(4) or NaIO4, respectively.