title: Phenylenebis(ethynyl)-tethered bis-BINOL ligands for enantioselective catalyst based on dimeric TiIV aggregate.
abstract: Bis-BINOLs 7a-c in which two BINOL units are tethered by phenylenebis(ethynyl) groups react with titanium tetraisopropoxide (2 equiv) to form intramolecular dimeric titanium(IV) aggregates 2a-c. Of these, 2a,b with an o-phenylenebis(ethynyl) tether are stable in the presence of excess titanium tetraisopropoxide. Complex 2a exhibits a relatively high enantioselectivity in asymmetric addition of diethylzinc to an aldehyde. [structure: see text]
authors.affiliation: Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan. harada@chem.kit.ac.jp
authors.forename: Toshiro
authors.initials: T
authors.lastname: Harada
authors.forename: Yuki
authors.initials: Y
authors.lastname: Hiraoka
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kusukawa
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Marutani
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Matsui
authors.forename: Masashi
authors.initials: M
authors.lastname: Nakatsugawa
authors.forename: Koso
authors.initials: K
authors.lastname: Kanda