Rosaprostol, an antiulcer drug, was prepared in five steps and in 36% overa
ll yield starting from 3-(dimethoxyphosphorylmethyl)cyclopent-2-enone (6).
The regioselective alkylation of 6 at C(2) with methyl 7-iodoheptanoate and
subsequent Horner-Wittig reaction with pentanal constitute the key steps o
f this total synthesis.