An efficient approach to optically active benzoprostacyclins by a two-component coupling process

Abstract

A highly efficient and practical synthesis of enantiomerically pure benzoprostacyclins, chemically stable and therapeutically useful prostaglandin I₂ analogues, is developed which includes an efficient preparation of 2-[3-bromo-2-(allyloxy)phenyl]-4-siloxycyclopent-2-en-1-one 3 in optically active form and the conjugate addition of ω side-chains onto 3 followed by cyclization to the key intermediate (1R, 2R, 3′S)-2-endo-siloxy-1-exo-(3′-siloxyalk-1-enyl)-3a,8b-cis-2,3,3a,8b-tetrahydro-1H-5-bromocyclopenta[b]benzofuran 4.