Towards Perfunctionalized Dodecahedranes—En Route to C 20 Fullerene

“One‐pot” substitution of the twenty hydrogen atoms in pentagonal dodecahedrane (C 20 H 20 ) by OH, F, Cl, and Br atoms is explored. Electrophilic insertion of oxygen atoms with DMDO and TFMDO as oxidizing reagents ended, far off the desired C 20 (OH) 20 , in complex polyol mixtures (up to C 20 H 10 (OH) 10 decols, a trace of C 20 H(OH) 19 ?). Perfluorination was successful in a NaF matrix but (nearly pure) C 20 F 20 could be secured only in very low yield. “Brute‐force” photochlorination (heat, light, pressure, time) provided a mixture of hydrogen‐free, barely soluble C 20 Cl 16 dienes in high yield and C 20 Cl 20 as a trace component. Upon electron‐impact ionization of the C 20 Cl 16 material sequential loss of the chlorine atoms was the major fragmentation pathway furnishing, however, only minor amounts of chlorine‐free C 20 + ions. “Brute‐force” photobrominations delivered an extremely complex mixture of polybromides with C 20 HBr 13 trienes as the highest masses. The MS spectra exhibited exclusive loss of the Br substituents ending in rather intense singly, doubly, and triply charged C 20 H 4–0 +(2+)(3+) ions. The insoluble ∼C 20 HBr 13 fraction (C 20 Br 14 trienes as highest masses) obtained along a modified bromination protocol, ultimately allowed the neat mass selection of C 20 − ions. The C 20 Cl 16 dienes and C 20 H 0–3 Br 14–12 tri‐/tetraenes, in spite of their very high olefinic pyramidalization, proved resistant to oxygen and dimerization (polymerization) but added CH 2 N 2 smoothly. Dehalogenation of the respective cycloaddition products through electron‐impact ionization resulted in C 22–24 H 4–8 +(2+) ions possibly constituting bis‐/tris‐/tetrakis‐methano‐C 20 fullerenes or partly hydrogenated C 22 , C 23 , and C 24 cages.