title: Synthesis of the Tricyclic Ring Structure of Daphnanes via Intramolecular [4 + 3] Cycloaddition/SmI2-Pinacol Coupling.
abstract: A synthetic approach toward the tricyclic 5,7,6-membered ring structure of daphnane-family natural products is described. An intramolecular [4 + 3] cycloaddition reaction of furan with an oxypentadienyl cation constructed the oxa-bridged bicyclic structure in a stereoselective fashion. Structural analysis revealed that the desired exo isomer was predominantly acquired through epimerization. Finally, formation of the five-membered ring was achieved through SmI2-mediated pinacol coupling.
authors.affiliation: †Center for Neuro-Medicine, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Republic of Korea.|‡Department of Biological Chemistry, Korea University of Science and Technology (UST), Daejeon, 305-350, Republic of Korea.|§Department of Medicinal Chemistry, Faculty of Pharmacy, University of Mansoura, Mansoura 35516, Egypt.
authors.forename: Ahmed H E
authors.initials: AH
authors.lastname: Hassan
authors.affiliation: †Center for Neuro-Medicine, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Republic of Korea.|‡Department of Biological Chemistry, Korea University of Science and Technology (UST), Daejeon, 305-350, Republic of Korea.
authors.forename: Jae Kyun
authors.initials: JK
authors.lastname: Lee
authors.affiliation: †Center for Neuro-Medicine, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Republic of Korea.|‡Department of Biological Chemistry, Korea University of Science and Technology (UST), Daejeon, 305-350, Republic of Korea.
authors.forename: Ae Nim
authors.initials: AN
authors.lastname: Pae
authors.affiliation: †Center for Neuro-Medicine, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Republic of Korea.|‡Department of Biological Chemistry, Korea University of Science and Technology (UST), Daejeon, 305-350, Republic of Korea.
authors.forename: Sun-Joon
authors.initials: SJ
authors.lastname: Min
authors.affiliation: †Center for Neuro-Medicine, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Republic of Korea.|‡Department of Biological Chemistry, Korea University of Science and Technology (UST), Daejeon, 305-350, Republic of Korea.
authors.forename: Yong Seo
authors.initials: YS
authors.lastname: Cho
mesh_terms: D000438:Alcohols / Q000737:chemistry*; D003500:Cyclization; D004224:Diterpenes / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D011506:Proteins / Q000737:chemistry*
chemical_list: D000438:Alcohols; D004224:Diterpenes; D011506:Proteins; C080380:sperm motility inhibitor 2; C011309:mezerein