title: Desymmetrization of 1,4-pentadien-3-ol by the asymmetric 1,3-dipolar cycloaddition of azomethine imines.
abstract: Desymmetrization of the divinyl carbinol 1,4-pentadien-3-ol was accomplished by the asymmetric 1,3-dipolar cycloaddition of azomethine imines based on a magnesium-mediated, multinucleating chiral reaction system utilizing diisopropyl (R,R)-tartrate as the chiral auxiliary. The corresponding optically active trans-pyrazolidines, each with three contiguous stereogenic centers, were obtained with excellent regio-, diastereo-, and enantioselectivity, with results as high as 99% ee. This reaction was shown to be applicable to both aryl- and alkyl-substituted azomethine imines. The use of a catalytic amount of diisopropyl (R,R)-tartrate was also effective when accompanied by the addition of MgBr2.
authors.affiliation: Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192 (Japan), Fax: (+81) 76-264-5742.
authors.forename: Mari
authors.initials: M
authors.lastname: Yoshida
authors.forename: Naotaro
authors.initials: N
authors.lastname: Sassa
authors.forename: Tomomitsu
authors.initials: T
authors.lastname: Kato
authors.forename: Shuhei
authors.initials: S
authors.lastname: Fujinami
authors.forename: Takahiro
authors.initials: T
authors.lastname: Soeta
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Inomata
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ukaji
keywords: azomethine imines; cycloaddition; desymmetrization; diisopropyl tartrate; pyrazolidines