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Regio‐ and Diastereoselective Synthesis of Bis‐ and Tetrakisadducts of C 70 by Directed Remote Functionalization Using Tröger Base Tethers
Author(s) -
Wong Wallace W. H.,
Diederich François
Publication year - 2006
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200501523
Subject(s) - surface modification , stereoselectivity , cyclopropanation , fullerene , circular dichroism , stereochemistry , base (topology) , chemistry , absolute configuration , enantioselective synthesis , organic chemistry , catalysis , mathematical analysis , mathematics
Abstract Double Bingel cyclopropanation of C 70 with bismalonates featuring Tröger base derivatives as chiral spacers afforded bisadducts with almost perfect regio‐ and stereoselectivity. The excellent directing property of these rigidly folded spacers in the remote functionalization of the higher fullerene was further highlighted by the selective formation of a product with a novel bisaddition pattern involving the C(7)C(22) and C(33)C(34) bonds of C 70 . Enantiomerically pure bisadducts of C 70 were prepared by highly diastereoselective transformations of bismalonates incorporating optically pure Tröger base tethers. The absolute configuration of these bisadducts was established by comparison of circular dichroism (CD) spectra with data reported in the literature. For the first time, optically active tetrakisadducts of a fullerene were prepared by two sequential chiral‐spacer‐controlled remote functionalizations.