title: Axially chiral binaphthyl surrogates with an inner N-H-N hydrogen bond.
abstract: Novel chiral binaphtyl surrogates with an inner hydrogen bond have been created. The NH appears at 13.0-13.3 ppm in thier (1)H NMR spectrum, indicating extremely strong hydrogen bonding. Enantiomers of these compounds were stable at ambient temperature and separable by HPLC with a chiral stationary phase. The half-lives of racemization of the enantiomer are in the range 3 months to 2 years at 20 degrees C, and the barriers for racemization are in the range 27.0 to 28.2 kcal/mol. An X-ray crystal analysis of the compound (R = CHPh(2)) shows that the pseudonaphthyl skeleton including CN...HN is almost completely planar and the dihedral angle between the pseudonaphthalene and naphthalene rings is 128 degrees .
authors.affiliation: Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Kawabata
authors.forename: Changsheng
authors.initials: C
authors.lastname: Jiang
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hayashi
authors.forename: Kazunori
authors.initials: K
authors.lastname: Tsubaki
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yoshimura
authors.forename: Swapan
authors.initials: S
authors.lastname: Majumdar
authors.forename: Takahiro
authors.initials: T
authors.lastname: Sasamori
authors.forename: Norihiro
authors.initials: N
authors.lastname: Tokitoh