Are the pyrazolines formed from the reaction of [60]fullerene with alkyl diazoacetates unstable?
نویسندگان
چکیده
[60]Fullerene-fused pyrazolines 1 were prepared by the reaction of C60 with alky diazoacetates under the solid-state high-speed vibration milling conditions as well as in toluene solution. Pyrazolines 1 were stable in refluxing toluene and its thermolysis process in 1,2-dichlorobenzene was investigated, the decomposition rates and activation energies of pyrazolines 1 were obtained. The current work demonstrated that the liquid-phase reaction of C60 with alkyl diazoacetates undergoes via 1,3-dipolar cycloaddition pathway at room temperature, or proceeds via carbene mechanism at a temperature of refluxing toluene, thus clarifies the previous ambiguity of its reaction mechanism. q 2004 Elsevier Ltd. All rights reserved.
منابع مشابه
Highly enantioselective catalytic 1,3-dipolar cycloadditions of α-alkyl diazoacetates: efficient synthesis of functionalized 2-pyrazolines.
Highly enantioselective 1,3-dipolar cycloaddition reactions of α-substituted diazoacetates are accomplished by catalysis of the chiral oxazaborolidinium ion. Functionalized 2-pyrazolines are synthesized in high to excellent enantiomeric ratios (up to >99 : 1). The synthetic utility of 2-pyrazoline was expanded via preparation of 2,4-diamino ester compounds bearing a chiral quaternary carbon cen...
متن کاملCatalytic carbon insertion into the β-vinyl C-H bond of cyclic enones with alkyl diazoacetates.
The first example of the boron Lewis acid catalyzed C(sp2)-H functionalization of cyclic enones was achieved using diazoacetates. The insertion of the carbon atom of diazoacetates utilizes BF3•Et2O or a newly designed oxazaborolidinium ion as a catalyst to afford β-functionalized cyclic enones from simple cyclic enones in a single step and high yields. The reaction mechanism was investigated wi...
متن کاملEnantioselective 1,3-dipolar cycloadditions of diazoacetates with electron-deficient olefins.
[reaction: see text] A general strategy for highly enantioselective 1,3-dipolar cycloaddition of diazoesters to beta-substituted, alpha-substituted, and alpha,beta-disubstituted alpha,beta-unsaturated pyrazolidinone imides is described. Cycloadditions utilizing less reactive alpha,beta-disubstituted dipolarophiles require elevated reaction temperatures, but still provide the corresponding pyraz...
متن کاملPhotoinduced charge separation in three-layer supramolecular nanohybrids: fullerene-porphyrin-SWCNT.
Photoinduced charge separation processes of three-layer supramolecular hybrids, fullerene-porphyrin-SWCNT, which are constructed from semiconducting (7,6)- and (6,5)-enriched SWCNTs and self-assembled via π-π interacting long alkyl chain substituted porphyrins (tetrakis(4-dodecyloxyphenyl)porphyrins; abbreviated as MP(alkyl)(4)) (M = Zn and H(2)), to which imidazole functionalized fullerene[60]...
متن کاملApplication of Triphenylphosphine for Facile Synthesis of Several Alkyl Acrylates from Heterocyclic Phenols
7-Hydroxycoumarine undergoes a smooth reaction with alkyl propiolates in the presence of triphenylphosphine (15 mol%) to produce the corresponding alkyl (E)-3-((2-oxo-2H-chromen- 7-yl)oxy)acrylate in good yields. When the reaction was performed by 3-hydroxyquinoline similar alkyl acrylates were obtained.
متن کامل