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hexabenzocoronene. Org. Lett. 2007, 9, 2485. (f) Luo, J.; Xu,
ty) for fruitful discussions and proofreading of the manu-
script.
1
2
3
4
5
6
7
8
X.; Mao, R.; Miao, Q. Curved Polycyclic Aromatic Molecules
That Are π-Isoelectronic to Hexabenzocoronene. J. Am. Chem.
Soc. 2012, 134, 13796.
(9) For a review of polyphenylenes for material science,
see: Berresheim, A. J.; Müller, M.; Müllen, K. Polyphenylene
Nanostructures. Chem. Rev., 1999, 99, 1747.
(10) For selected examples of radical cation-induced reac-
tion by iron(III) salt, see: (a) Bell, F. A.; Crellin, R. A.; Fujii,
H.; Ledwith, A. Cation-radicals: Metal-catalysed Cyclodimeri-
sation of Aromatic Enamines. J. Chem. Soc. D, 1969, 1969,
251. (b) Ohara, H.; Itoh, T.; Nakamura, M.; Nakamura, E. [2 +
2]-Cycloaddition Reaction of Styrene Derivatives Using an
REFERENCES
(1) Linker, T. Cerium(IV) and other oxidizing agents, in
Radicals in Organic Synthesis; Renaud, P.; Sibi, M. P. Eds.;
Wiley: Weinheim, 2001; pp. 219–228.
(2) For review of radical cation-induced reaction, see:
Schmittel, M.; Burghart, A. Understanding Reactivity Patterns
of Radical Cations. Angew. Chem. Int. Ed. 1997, 36, 2550.
(3) Wang, X. Isolation and crystallization of radical cations
by weakly coordinating anions, in Organic Redox Systems:
Synthesis, Properties, and Applications, Nishinaga, T. Ed.;
Wiley: New Jersey, 2015; pp. 523–544.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Fe(III) Salt Catalyst. Chem. Lett. 2001, 30, 624.
(c)
Cavanagh, C. W.; Aukland, M. H.; Hennessy, A.; Procter, D. J.
Iron-mediated C–H Coupling of Arenes and Unactivated Ter-
minal Alkenes Directed by Sulfur. Chem. Commun. 2015, 51,
9272.
(11) (a) Meyer, S.; Koch, R.; Metzger, J. O. Investigation of
Reactive intermediates of Chemical Reactions in Solution by
Electrospray Ionization Mass Spectrometry: Radical Cation
Chain Reactions. Angew. Chem. Int. Ed. 2003, 42, 4700. (b)
Marquez, C. A.; Wang, H.; Fabbretti, F.; Metzger, J. O. Elec-
tron-Transfer-Catalyzed Dimerization of trans-Anethole: De-
tection of the Distonic Tetramethylene Radical Cation Inter-
mediate by Extractive Electrospray Ionization Mass Spec-
trometry. J. Am. Chem. Soc. 2008, 130, 17208.
(12) Rathore, R.; Kochi, J. K. Isolation of Novel Radical
Cations from Hydroquinone Ethers. Conformational Transition
of the Methoxy Group upon Electron Transfer. J. Org. Chem.
1995, 60, 4399.
(13) Gao, Y.; Guery, J.; Jacoboni, C. FeCl3 Behavior in Ac-
etonitrile: Structures of [FeCl2(CH3CN)4][FeCl4] and
[AlCl(CH3CN)5][FeCl4]2•CH3CN. Acta Cryst. C 1993, 49,
147.
(14) Dissociation of chloride from A is another possible
rate-limiting step. To exclude this possibility, we conducted
control experiments in the presence of chloride scavengers
(see Table S1 in Supporting Information). However, chloride
dissociation was not observed in these reactions. Therefore,
dissociation of chloride and the generation of FeCl2+ are less
likely.
(15) Okada, Y.; Chiba, K. Redox-Tag Processes: Intramo-
lecular Electron Transfer and Its Broad Relationship to Redox
Reactions in General. Chem. Rev. 2018, 118, 4592.
(16) (a) Bellville, D. J.; Bauld, N. L.; Pabon, R.; Gardner,
S. A. Theoretical Analysis of Selectivity in the Cation-radical
Diels–Alder. J. Am. Chem. Soc. 1983, 105, 3584. (b) Pabon, R.
A.; Bellville, D. J.; Bauld, N. L. Cation Radical Diels-Alder
Reactions of Electron-rich Dienophiles. J. Am. Chem. Soc.
1983, 105, 5158. (c) Reynolds, D. W.; Bauld, N. L. The Diene
Component in the Cation Radical Diels-Alder. Tetrahedron
1986, 42, 6189. (d) Yueh, W.; Bauld, N. L. Mechanistic As-
pects of Aminium Salt-Catalyzed Diels–Alder Reactions: the
Substrate Ionization Step. J. Phys. Org. Chem. 1996, 9, 529.
(17) (a) Lin, S.; Ischay, M. A.; Fry, C. G.; Yoon, T. P. Radi-
cal Cation Diels–Alder Cycloadditions by Visible Light Pho-
tocatalysis. J. Am. Chem. Soc. 2011, 133, 19350. (b) Steven-
son, S. M.; Shores, M. P.; Ferreira, E. M. Photooxidizing
Chromium Catalysts for Promoting Radical Cation Cycloaddi-
tions. Angew. Chem. Int. Ed. 2015, 54, 6506. (c) Higgins, R.
F.; Fatur, S. M.; Shepard, S. G.; Stevenson, S. M.; Boston, D.
J.; Ferreira, E. M.; Damrauer, N. H.; Rappé, A. K.; Shores, M.
(4) For a review of recent uses of FeCl3, see: Diaz, D. D.;
Miranda, P. O.; Padrón, J. I.; Martin, V. S. Recent Uses of
Iron(III) Chloride in Organic Synthesis. Curr. Org. Chem.
2006, 10, 457.
(5) For reviews of iron-mediated oxidative coupling, see:
(a) Sarhan, A. A. O.; Bolm, C. Iron(III) Chloride in Oxidative
C–C Coupling Reactions. Chem. Soc. Rev. 2009, 38, 2730. (b)
Jia, F.; Li, Z. Iron-catalyzed/mediated Oxidative Transfor-
mation of C–H Bonds. Org. Chem. Front. 2014, 1, 194.
(6) For selected examples of oxidative coupling reactions,
see: (a) Jempty, T. C.; Miller, L. L.; Mazur, Y. Oxidative Cou-
pling Reactions Using Silica-bound Ferric Chloride. J. Org.
Chem. 1980, 45, 749. (b) Jempty, T. C.; Gogins, K. A. Z.; Ma-
zur, Y.; Miller, L. L. FeCl3/SiO2 Reacts as Oxidant or Lewis
Acid with Phenol Ethers. J. Org. Chem. 1981, 46, 4545. (c)
Boden, N.; Bushby, R. J.; Lu, Z.; Headdock, G. Synthesis of
Dibromotetraalkoxybiphenyls Using Ferric Chloride. Tetrahe-
dron Lett. 2000, 41, 10117. (d) Siove, A.; Adès, D. Synthesis
by Oxidative Polymerization with FeCl3 of a Fully Aromatic
Twisted Poly(3,6-carbazole) with a Blue-violet Luminescence.
Polymer 2004, 45, 4045. (e) Wadumethrige, S. H.; Rathore, R.
A Facile Synthesis of Elusive Alkoxy-substituted Hexa-peri-
hexabenzocoronene. Org. Lett. 2008, 10, 5139. (f) Dou, C.;
Saito, S.; Matsuo, K.; Hisaki, I.; Yamaguchi, S. A Boron-
Containing PAH as a Substructure of Boron-Doped Graphene.
Angew. Chem. Int. Ed. 2012, 51, 12206.
(7) For review of Scholl reaction, see: Grzybowski, M.;
Skonieczny, K.; Butenschön, H.; Gryko, D. T. Comparison of
Oxidative Aromatic Coupling and the Scholl Reaction. Angew.
Chem. Int. Ed. 2013, 52, 9900.
(8) For selected examples of Scholl reaction, see: (a) Scholl,
R.; Seer, C. Abspaltung Aromatisch gebundenen Wasserstoffs
und Verknüpfung Aromatischer Kerne durch Alumini-
umchlorid. Justus Liebigs Ann. Chem. 1912, 394, 111. (b)
Fechtenkötter, A.; Saalwächter, K.; Harbison, M. A.; Müllen,
K.; Spiess, H. W. Highly Ordered Columnar Structures from
Hexa-peri-hexabenzocoronenes–Synthesis, X-ray Diffraction,
and Solid-State Heteronuclear Multiple-Quantum NMR Inves-
tigations. Angew. Chem. Int. Ed. 1999, 38, 3039. (c) Ito, S.;
Herwig, P. T.; Böhme, T.; Rabe, J. P.; Rettig, W.; Müllen, K.
Bishexa-peri-hexabenzocoronenyl: A “Superbiphenyl”. J. Am.
Chem. Soc. 2000, 122, 7698. (d) Wehmeier, M.; Wagner, M.;
Müllen, K. Novel Perylene Chromophores Obtained by a Fac-
ile Oxidative Cyclodehydrogenation Route. Chem. Eur. J.
2001, 7, 2197. (e) Dou, X.; Yang, X.; Bodwell, G. J.; Wagner,
M.; Enkelmann, V.; Müllen, K. Unexpected Phenyl Group
Rearrangement during an Intramolecular Scholl Reaction
Leading
to
an
Alkoxy-Substituted
Hexa-peri-
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