We have disclosed a new class of stable PGI2 analogue, 5, 6, 7-trinor-4, 8-inter-m- phenylene PGI2 which has a phenyl ether moiety instead of enol-ether skeleton in PGI2. The m-phenylene PGI2 and its derivative (Beraprost) were synthesized via dihydrocyclopenta [b] benzofuran derivatives as key intermediates by ortho-selective metal-halogen exchange reaction with Grignard reagents and subsequent copper-catalyzed cyclization. The ω-side ...