title: Origin of stereocontrol in guanidine-bisurea bifunctional organocatalyst that promotes α-hydroxylation of tetralone-derived β-ketoesters: asymmetric synthesis of β- and γ-substituted tetralone derivatives via organocatalytic oxidative kinetic resolution.
abstract: The mechanism of asymmetric α-hydroxylation of tetralone-derived β-ketoesters with guanidine-bisurea bifunctional organocatalyst in the presence of cumene hydroperoxide (CHP) was examined by means of DFT calculations to understand the origin of the stereocontrol in the reaction. The identified transition-state model was utilized to design an enantioselective synthesis of β- or γ-substituted tetralones by catalytic oxidative kinetic resolution reaction of tetralone-derived β-ketoesters. This kinetic resolution reaction proceeded with high selectivity, and selectivity factors (s value) of up to 99 were obtained. The potential utility of this oxidative kinetic resolution method for synthesis of natural products was confirmed by applying it to achieve an enantioselective synthesis of (+)-linoxepin (13) from β-substituted tetralone rac-7 in only six steps.
authors.affiliation: Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology , 2-24-16, Naka-cho, Koganei city, 184-8588, Tokyo Japan.
authors.forename: Minami
authors.initials: M
authors.lastname: Odagi
authors.forename: Kota
authors.initials: K
authors.lastname: Furukori
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Makoto
authors.initials: M
authors.lastname: Sato
authors.forename: Keisuke
authors.initials: K
authors.lastname: Iida
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamanaka
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nagasawa
mesh_terms: D002384:Catalysis; D004952:Esters; D019791:Guanidine / Q000737:chemistry*; D006900:Hydroxylation; D007700:Kinetics; D017705:Lignans / Q000138:chemical synthesis / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D013237:Stereoisomerism; D044024:Tetralones / Q000737:chemistry*; D014508:Urea / Q000737:chemistry*
chemical_list: D004952:Esters; D017705:Lignans; D044024:Tetralones; C583976:linoxepin; C009423:beta-tetralone; D014508:Urea; D019791:Guanidine