Synthesis and Characterization of Diethynylmethanobuckminsterfullerene, a Building Block for Macrocyclic and Polymeric Carbon Allotropes

Multiple Adducts of C60 by Tether‐Directed Remote Functionalization and synthesis of soluble derivatives of new carbon allotropes Cn(60+5)

“…In contrast, treatment of 29 with Bu,NF on SiO, in anhydrous THF caused a very clean deprotection affording the diethynyl derivative 30 in 90 % yield after chromatography (Si0,-H, CH,Cl,/AcOEt 100: 1.5) [12] [20]. This successful reaction again illustrates the differences in reactivity between lower and higher C,,-adducts : when Rubin and coworkers applied Bu,NF to deprotect 61,61 -bis[(trimethylsilyl)-ethynyl]-l,2-dihydro-l ,Zmethano[60]fullerene, mainly decomposition and polymerization of the mono-adduct occurred, presumably induced by attack of the nucleophilic F-anion [41]. The MALDI-TOF mass spectrum of 30 again showed a pronounced preference for loss of the diethynylmethano over the malonate ester groups.…”

“…The acetylenic C-atom resonances in 26 appeared at 88. 41 and 71.77 ppm, whereas those in 27 are located at 75.77 and 69.49 ppm, with the differences in chemical shift presumably reflecting the different bending of the butadiynediyl fragments from linearity in the two compounds. The UVjVIS spectra of 26 and 27 are similar to those of monomeric 30, with the exception of the increase in molar extinction coefficients as the number of fullerene moieties per molecule increases (Fig.…”

Fullerene‐Acetylene Molecular Scaffolding: Chemistry of 2‐functionalized 1‐ethynylated C60, oxidative homocoupling, hexakis‐adduct formation, and attempted synthesis of C

“…In a series of earlier papers [2], we reported the synthesis of diethynylmethanofullerene 3 [4] and its oxidative homo-and heterocoupling reactions under Glaser-Hay conditions, which resulted in the formation of the first dumbbell-type bisfullerene molecule soluble enough for full spectroscopic characterization, including X-ray crystallography [2c]. All-carbon molecules 1 (n = 1, 2, .…”

“…In contrast, cyclooligomerizations of a diethynylmethano-functionalized C,, hexakis-adduct afforded soluble derivatives of the cyclic oligomers 1 (with n = 1 and 2) as the major products [5]. By analogy, oxidative cyclization of 1,2-diethyny1[60]fullerene 4 should potentially give access to 2, another family of fullerene-acetylene hybrid allotropes. As a result of the smaller angle between the two alkyne groups in 4 (as compared to 3), we expected dimeric fullerene 2 (n = 0), a compound that might have enough solubility for isolation and spectroscopic characterization, to be the major product from the cyclo-oligomerization of 4.…”

“…Alcohol 10 was not stable under these conditions and, in the absence of O,, readily extruded formaldehyde to give K' salt 7c. Therefore, alcohol 10 was converted in 82% yield to the corresponding chiral 3,4,5, ether 13 by treatment with a large excess of 3,4-dihydro-2H-pyran (Dhp)/pyridinium p-toluenesulfonate (PPTS) [9] in refluxing THF. Apart from serving as a protecting group, the Thp moiety also raised the solubility of the compound.…”