Strained Mono‐ and Dications. On the Structures of [(CCH2)7H]2⊕ and [(CCH3)7CH3]2⊕ Dications

The reactions of alcohol 1 with HF‐SbF5 and of alcohol 8 with FSO3H‐SbF5 at low temperatures afforded dications [(CCH3)7H]2⊕ and [(CCH3)7CH3]2⊕, respectively. Both NMR (1H and 13C) data and analysis of the products, obtained upon quenching of the cations, were used to discuss the possible structures of these cations. Both ions showed a remarkable NMR behaviour, viz. an equivalency of all methylgroups on the one hand and all skeleton carbon atoms on the other hand, indicating a high symmetry or a rapid (on the NMR time scale) process. Using model compounds the weighted average 13C‐NMR chemical shifts of reasonable structures for the ions were calculated and compared with the experimentally obtained values. The conclusion is drawn that the former reaction presumably leads to dications 34 and 36 and the latter reaction to dication 51.