A Parallel Library of all Seven A2+B2+C2Th Regioisomeric Hexakisadducts of Fullerene C60: Inspiration from Werner's Octahedral Stereoisomerism

A study towards the regioselective synthesis of the e,e,e trisadduct of C60 via the [4+2] Diels-Alder reaction with tethers bearing ortho-quinodimethane precursors

“…A cycloadduct of C 60 [Scheme 2, (b)] derived from the Diels-Alder addition of a diene to C 60 is, however, sensitive to oxidation which proceeds via the "ene" reaction of singlet oxygen ( 1 O 2 ) 22 with the double bond of the cyclohexene ring to afford the corresponding allylic hydroperoxide 3. [23][24][25] The fullerene core acts as a photosensitizer and thus, adducts of this kind should be handled in the dark. This problem can be tackled if ortho-quinodimethanes are used as dienes [Scheme 2, (c)] and in such a case the corresponding cycloadducts 4 are thermally and photochemically stable.…”

Stereochemie

“…Ähnlich wurde die Struktur von Fullerenen zur Beschreibung ihrer Konfiguration mitunter auf ein Oktaeder reduziert [14], obwohl die so beschriebenen Isomere zum Teil Konstitutionsisomere sind. B.…”

“…anomerer 88 Diene 19,20,51,63,93 1,17 4, Konfiguration 8,9,51,konjugierte 31,32,kumulierte 20,21,51,52,partielle 15,52,53,60,63,prostereogen 77,100,Sequenzregel bei 31,als stereogene Einheit 38,39,43,51,52,91 Doppelbindungsisomerie 8,9,38,39,43,[51][52][53]24,25,96 15,16,28,52,62,63 Eliminierung 22,23,93 enantiomer 45,67 Enantiomer 3,14,17,24,[41][42][43][44][45]…”

Regiochemistry of Multiple Additions

“…Following their initial studies, Rubin and co-workers subsequently succeeded in synthesizing a complete "library" of all-e C 60 [2:2:2] hexakisadducts with three pairs of addends in octahedral sites [104]. Using a "mer-313" regiocontrol strategy, involving regiochemically distinct cyclopropanations of trans-1 tethered bisadduct 110, the authors prepared four regioisomeric trismalonates, each with two different ester moieties.…”