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Easy Access to Modified Cyclodextrins by an Intramolecular Radical Approach
Author(s) -
AlvarezDorta Dimitri,
León Elisa I.,
Kennedy Alan R.,
Martín Angeles,
PérezMartín Inés,
Suárez Ernesto
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201412300
Subject(s) - intramolecular force , chemistry , ring (chemistry) , hydrogen atom , crystallography , primary (astronomy) , solid state , atom (system on chip) , diffraction , stereochemistry , group (periodic table) , organic chemistry , physics , astronomy , computer science , optics , embedded system
A simple method to modify the primary face of cyclodextrins (CDs) is described. The 6 I ‐ O ‐yl radical of α‐, β‐, and γ‐CDs regioselectively abstracts the H5 II , located in the adjacent D ‐glucose unit, by an intramolecular 1,8‐hydrogen‐atom‐transfer reaction through a geometrically restricted nine‐membered transition state to give a stable 1,3,5‐trioxocane ring. The reaction has been extended to the 1,4‐diols of α‐ and β‐CD to give the corresponding bis(trioxocane)s. The C 2 ‐symmetric bis(trioxocane) corresponding to the α‐CD is a stable crystalline solid whose structure was confirmed by X‐ray diffraction analysis. The calculated geometric parameters confirm that the primary face is severely distorted toward a narrower elliptical shape for this rim.