A concise approach to both enantiomers of phytoprostane B1 type II

The synthesis of enantiomeric phytoprostane B₁ type II methyl esters has been accomplished in approximately 30% overall yield via two basic transformations starting from 3-[(dimethoxyphosphoryl)methyl]cyclopentenone as a key reagent. They include ethylation of the ring C(2) carbon and a Horner olefination reaction using the phosphonate moiety at C(3). The novel components of the Horner reaction, the enantiomeric methyl 9-formyl-9-hydroxynanoates, were easily prepared from racemic methyl 9-hydroxy-10-undecenoate via asymmetric Sharpless epoxidation (kinetic resolution) followed by ozonolysis.