title: Stereoselective total synthesis of (+)-Scyphostatin via a pi-facially selective Diels-Alder reaction.
abstract: A stereoselective total synthesis of scyphostatin is described. The hydrophilic moiety was stereoselectively synthesized via (i) a highly pi-facially selective Diels-Alder reaction of a spirolactone generated from L-tyrosine and (ii) a hydroxy group directed epoxidation as key reactions. The hydrophilic moiety was combined with the hydrophobic side chain in the final stage. Total synthesis was achieved by overcoming the instability of the C5-C6 epoxide ring with carefully executed mild reactions. In the course of this work, it was revealed that we had mistakenly assigned the relative stereochemistry of the C5-C6 epoxide ring of the end product in our previous model study. Revision of the stereochemical assignment in the model study is described. A diastereomer of (+)-scyphostatin epimeric at C5 and C6 (the epoxide region) was also synthesized.
authors.affiliation: Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan. rtakagi@hiroshima-u.ac.jp
authors.forename: Ryukichi
authors.initials: R
authors.lastname: Takagi
authors.forename: Wataru
authors.initials: W
authors.lastname: Miyanaga
authors.forename: Kengo
authors.initials: K
authors.lastname: Tojo
authors.forename: Shinjiro
authors.initials: S
authors.lastname: Tsuyumine
authors.forename: Katsuo
authors.initials: K
authors.lastname: Ohkata
mesh_terms: D000577:Amides / Q000138:chemical synthesis* / Q000737:chemistry; D003500:Cyclization; D008968:Molecular Conformation; D015394:Molecular Structure; D011753:Pyrones / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000577:Amides; D011753:Pyrones; C121123:scyphostatin