title: A concise synthesis of the pentacyclic framework of cortistatins.
abstract: An efficient synthesis of the pentacyclic framework of cortistatins has been developed. The key strategy comprises assembly of the A- and the CD-ring fragments by Knoevenagel reaction, facile formation of the pyran ring via electrocyclization, and construction of the seven-membered B-ring by radical addition to an alpha,beta-unsaturated ketone.
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, and Research and Analytical Center for Giant Molecules, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan. s-yamashita@mail.tains.tohoku.ac.jp
authors.forename: Shuji
authors.initials: S
authors.lastname: Yamashita
authors.forename: Kentaro
authors.initials: K
authors.lastname: Iso
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hirama
mesh_terms: D000447:Aldehydes / Q000138:chemical synthesis / Q000737:chemistry; D018360:Crystallography, X-Ray; D007659:Ketones / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D009479:Neuropeptides / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000447:Aldehydes; D007659:Ketones; D009479:Neuropeptides; C099323:cortistatin