The Bingel addition of a trimalonate derived from a chiral, cyclotriveratrylene (CTV)-based tripodal tether to C 60 was reinvestigated. The present use of enantiomerically pure (P)-and (M)-configured CTV units in the tether allowed the isolation of a total of four enantiomerically pure C 3 -symmetric trisadducts of [60]fullerene (two from each CTV enantiomer). With the support of NMR and UV/Vis spectroscopy, electronic (ECD) and vibrational (VCD) circular dichroism spectroscopic analysis (comparison to ECD data of known compounds and to ECD and VCD data calculated by TD-DFT or
By addition of an enantiomerically pure nitrile oxide to C 70 , four chiral isoxazolo [70]fullerene isomers were prepared and isolated in pure state: two constitutional isomers resulting from addition to one of the bonds radiating from the polar pentagons, and a constitutionally different pair of diastereoisomers resulting from addition to a hexagon-hexagon fusion site parallel to the equator of the fullerene. After elimination of the stereogenic center from the side chain, the former two adducts become achiral, while the latter two are separately transformed into enantiomeric fullerene derivatives with a non-inherently chiral addition pattern as sole stereogenic element. In the present work, chiral [70]fullerene derivatives with a non-inherently chiral functionalisation pattern were isolated in enantiomerically pure form for the first time. Their absolute configuration was assigned based on the good agreement between experimental circular dichroism (CD) data and CD spectra calculated using the ZINDO method.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.