A novel synthesis of racemic and enantiomeric forms of prostaglandin B-1 methyl ester

3-(Dimethoxyphosphorylmethyl)cyclopent-2-enome was converted into (+/-)-pro staglandin B-1 methyl ester in two steps involving regioselective alkylatio n at C(2) with methyl 7-iodoheptanoate and subsequent Horner-Wittig reactio n with dimer of 2-hydroxyheptanal (42% overall yield). The use of (R)- and (S)-2-(tert-butyldimethylsilyloxy)heptanal for the Horner olefination re ac tion gave, after deprotection of the hydroxy group, the enantiopure forms o f the title compound in 28% overall yield.