Enantiopure Dendrimers Derived from the 1,1′-Binaphthyl Moiety: A Correlation Between Chiroptical Properties and Conformation of the 1,1′-Binaphthyl Template
✍ Scribed by Carlo Rosini; Stefano Superchi; H. W. I. Peerlings; E. W. Meijer
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 498 KB
- Volume
- 2000
- Category
- Article
- ISSN
- 1434-193X
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✦ Synopsis
of the DeVoe polarizability model the intensity of the 1 B couplet has been calculated vs. the dihedral angle θ. This The absorption and CD spectra of a series of Fre ´chet (compounds 7-10) and backfolding (compounds 11-12) analysis provides θ angles of 95-110°for the Fre ´chet dendrimers and 100-110°for the backfolding compounds. dendrimers derived from enantiopure (S)-2,2Ј-dihydroxy-1,1Ј-binaphthalene have been recorded (THF) in the range These values clearly indicate that the torsional angle θ, defined by the two naphthalene planes, never exceeds the 200-350 nm. All the compounds examined show a positive couplet between 200 and 240 nm ( 1 B transition of the 2-critical value of 110°. This investigation confirms the wide utility of CD spectroscopy to provide geometrical information naphthol chromophore), the intensity of which (∆ε max of the low-energy branch) ranges between 100 and 40. By means that cannot be obtained by other types of structural analysis.
son et al. on the optical activity of biaryl compounds. Alpresence of NaHCO 3 . In our first approach to backfolding, Fax: (internat.) ϩ 39-0971/202223 the normal Fre ´chet-type [11] dendritic wedge of the first gen-E-mail: [email protected] eration was reacted with 16 to give 17. After reduction to [b]