SCIENCE/TECHNOLOGY
Sugar Derivatives, New Production Methods among Fullerene Advances • Fullerene sugars exhibit curious optical behavior; C70 and larger molecules form by electron beam evaporation, sputtering hemists have synthesized the first optically pure derivatives of fullerenes by linking buckminsterfullerene, C^, and D-glucose. Although the two fullerene sugars synthesized so far differ only in the protecting groups on the glucose, their circular dichroism (CD) spectra are strikingly different. Once the protecting groups are removed, C60-glucose, as well as other fullerene sugars, may be useful in studying the biochemical and pharmacological properties of fullerenes, says François Diederich, a chemistry professor at the Federal Technical Institute (ΕΤΗ), Zurich, who collaborated in this research with Andrea Vasella, a chem istry professor at the University of Zur ich. Diederich points out that some ful lerenes are themselves chiral. Research last year by Diederich and Robert L. Whetten, a chemistry professor at the University of California, Los Angeles, for example, demonstrated that C 76 contains a helical twist and, therefore, exists in left- and right-handed forms (C&EN, Sept. 16,1991, page 5). Howev er, efforts to separate the two C76 enantiomers have not yet been successful. Chiral C^ derivatives also have been synthesized, but once again, efforts to separate the enantiomers have not yet been successful. Vasella, Diederich, and their cowork ers react C 60 with an O-benzyl or O-pivaloyl protected diazirine deriva tive of D-glucose [Angew. Chem. Int. Ed. Engl, 31,1388 (1992)]. Because the reac tion does not affect the structure of the
C^Q reacts to produce fullerene sugars
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NOVEMBER 9,1992 C&EN
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