Regioselective Eightfold and Tenfold Additions of a Pyridine‐Modified Organocopper Reagent to [60]Fullerene

Abstract

The amount of pyridine (py) is essential for the outcome of the efficient addition of aryl copper compounds to [60]fullerene on a 20‐mg to 1‐g scale (see scheme). It controls—in addition to the installation of an ortho‐methyl group on the aryl reagent—the regioselectivity and the number of aryl groups introduced. The tenfold‐addition adduct may be further converted into the corresponding double‐decker metallocene.

Synthetic approaches to aromatic belts: building up strain in macrocyclic polyarenes

“…Although FVP is capable of building up strain energy of such magnitudes, 34 Herges and coworkers reported the failure of an attempt to close the walls of the picotube pyrolytically at 800 1C (Scheme 11). 36 Instead of cyclodehydrogenation, the pyrolysis reaction led to a mixture of products, in most of which the quinoid bonds and the neighboring single bonds were cleaved (52,53,54). An unexpected rearrangement also took place, affording an odd conjugated belt ( 51) that includes a seven-membered ring, probably formed in a radical mechanism.…”

“…51 Later on Nakamura and coworkers further improved on the synthesis, by shortening it to a single step of regioselective ten-fold addition. 52 By reacting 88 with the organocopper reagent in the presence of an appropriately excessive amount of pyridine, the desired [10]cyclophenacene derivative 93 was obtained, along with other products of deca-and pentaaddition (Scheme 20), in 92% overall yield. Substitution of the pyridine enabled some tweaking of the relative yields of the products, thus revealing the two mechanistic pathways for the multiple addition reactions.…”

Reactions of Anionic Oxygen Nucleophiles with C60Revisited

“…Fullerenes, represented by C 60 , are electron-deficient molecules and are favorable for reactions with nucleophiles . However, the so far well-established nucleophilic reactions for fullerenes are mostly based on carbon nucleophiles, including organometallic reagents, − a cyanide anion, depronated α-halo esters or ketones for Bingel reactions, , and transition metal catalyzed arylation and allylation reactions, , while reactions with oxygen nucleophiles such as hydroxide and alkoxide anions are often overlooked, since such reactions usually result in complex mixtures rather than well-structured organofullerenes. ,− …”

Preparation of Pentafluorinated Phenyl-Monohydro[60]fullerenes

“…In contrast however, treatment of [60]fullerene with an excess of (2-methylphenyl)magnesium bromide resulted in formation of the corresponding octa-adduct. 11 In the present case, it might be possible that magnesium bromide fluoride (FMgBr) was eliminated from (2-fluorophenyl)magnesium bromide, which is one of the reported methods for generating benzynes. 12…”