Regio-, Stereo-, and Atropselective Synthesis of C60 Fullerene Bisadducts by Supramolecular-Directed Functionalization

Abstract

The regio- and stereocontrolled synthesis of fullerene bisadducts is a topic of increasing interest in fullerene chemistry and a key point for the full exploitation of these derivatives in materials science. In this context, while the tether-directed remote functionalization strategy offers a valid approach to this synthetic challenge, no examples of such control have yet been reported using nontethered species. Presented here is a conceptually novel, supramolecular-directed functionalization approach in which noncovalent interactions between untethered residues have been used, for the first time, to amplify (>2800-fold) the regio-, stereo-, and atropselective formation of a C60 fullerene bisadduct racemate from a complex mixture of 130 bisadducts. Remarkably, both enantiomers, which present a sterically demanding cis-1 C60 addition pattern, represent the first examples of fullerene derivatives which combine central, axial, and helical chirality.

Keywords: atropisomerism; cycloaddition; fullerenes; phthalocyanines; supramolecular chemistry.