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DOI: 10.1055/s-2007-968211
Regioselective Multiple Additions to C60
Contributor(s):Timothy M. Swager, Eric L. DaneUniversity of California, Los Angeles, USA
Switch of Electronic Reactivity in Fullerene C60: Activation of Three trans-4 Positions via Temporary Saturation of the cis-1 Positions
Org. Lett. 2006, 8: 6075-6078
Publication History
Publication Date:
20 February 2007 (online)
Key words
fullerenes - regioselectivity - Bingel reaction
Significance
A temporary directing group, which sterically hinders and electronically alters the preferred substitution sites of C60, is used to regioselectively substitute C60 at three of the trans-4 positions to form a C 3v -symmetric molecule. The directing group is attached to C60 via a Diels-Alder reaction and the Bingel reaction is then used to add cyclopropane adducts. The authors found that dimethylanthracene was required as a templating agent. The directing group is removed from the substituted product by heating in the prescence of a great excess of C60.
Comment
Fullerenes, specifically C60, have been investigated extensively in recent decades and many methods to functionalize them have been developed. Substituting C60 regioselectively still remains a challenging problem due to the inherent symmetry of the molecule. This application represents one method to do so. A large directing group must be attached and then removed, but the resulting product is one that is not easily accessible by any of the current methods.