title: Enantioselective Total Synthesis of Beraprost Using Organocatalyst.
abstract: A convergent and enantioselective total synthesis of the most active isomer of beraprost was achieved in 17 pots. A unique tricyclic core in beraprost was synthesized efficiently by utilizing the asymmetric organocatalyst-mediated formal [3 + 2] cycloaddition reaction of succinaldehyde with nitroalkene as a key step. The synthesis of the optically active Horner-Wadsworth-Emmons reagent for the construction of the ω-side chain was also established by means of the enantioselective Michael reaction of crotonaldehyde with nitromethane catalyzed by the organocatalyst developed by our group.
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University , 6-3 Aramaki-Aza, Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Umemiya
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University , 6-3 Aramaki-Aza, Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sakamoto
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University , 6-3 Aramaki-Aza, Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
authors.forename: Genki
authors.initials: G
authors.lastname: Kawauchi
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University , 6-3 Aramaki-Aza, Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
authors.forename: Yujiro
authors.identifier: 0000-0002-1838-5389
authors.initials: Y
authors.lastname: Hayashi