The reactions of norbornene, norbornadiene and 7-oxanorbornene with methyl 3-(chloromethyl) phenoxyacetate (4), optically pure (S)-1-octyn-3-ol (5), and 8% Pd(PPh3)4 afford in one step satisfactory yields of the corresponding esters 6, 7 and 8 respectively, readily saponified to the first interphenylene prostaglandin endoperoxide analogs 10, 11 and 12 respectively.