Scheme 2. Synthetic Routes to the F6- and F3[33]CP’s 4 and 3a
a (i) NaOH, n-Bu4NI, CH2Cl2-H2O, reflux, 10 h; (ii) concentrated HCl, CH2Cl2, room temperature (7%); (iii) KOH, H2NNH2‚H2O,
diethylene glycol (12%); (iv) NaH, DMF, room temperature, overnight; (v) concentrated HCl, CH2Cl2, room temperature (10%); (vi) KOH,
H2NNH2‚H2O, diethylene glycol (62%).
We would like to report here the successful synthesis of
the tri- and hexafluoro[33]CP’s 3 and 4 as precursors to the
photoreaction and their interesting crystal structural proper-
ties. Previously, we reported the first crystal structure of [36]-
(1,2,3,4,5,6)CP as a TCNQ-F4 complex6 and the relationship
between the crystal structural properties and conductivities
of the charge transfer (CT) complexes of [33]CP 1 and [36]-
(1,2,3,4,5,6)CP with TCNQ and TCNQ-F4.7
yields of the TosMIC coupling were low, but our synthetic
routes provided straightforward and short-step approaches
to the fluorinated [33]CP’s.
1
The H NMR spectrum of 3 shows the aromatic proton
signal at 6.82 ppm as a singlet. In the 19F NMR spectra, the
fluorine signals of 3 and 4 appear as singlets at 45.8 and
46.3 ppm from C6F6, respectively. These NMR data are in
good agreement with the expected structures and suggest that
the trimethylene bridges are mobile at ambient tempera-
tures.14
F6[33]CP 4 was synthesized by TosMIC coupling8 between
1,3,5-tris(bromomethyl)-2,4,6-trifluorobenzene 69 and TosMIC
710 under phase-transfer conditions (Scheme 2), followed by
acid hydrolysis (7%) and the reduction of the resultant F6-
ketone 8 (12%).11 Similarly, coupling of 6 with the TosMIC
adduct 9 in the presence of NaH in DMF12 and subsequent
acid hydrolysis gave the ketone 10 (10%). Reduction of the
carbonyl groups of 10 afforded F3[33]CP 3 (62%).13 The
Figure 1 shows the electronic spectra of a series of F1-,
F3-, and F6[33]CPs 2, 3, and 4 along with the parent 1 as a
(5) (a) Camggi, C.; Gozzo, F.; Cevidalli, G. B. J. Chem. Soc., Chem.
Commun. 1966, 313. (b) Brlond, M. G.; Hszelclins, R. N. J. Chem. Soc.,
Perkin Trans. 1 1975, 2005.
(6) Yasutake, M.; Sakamoto, Y.; Onaka, S.; Sako, K.; Tatemitsu, H.;
Shinmyozu, T. Tetrahedron Lett. 2000, 41, 7933.
(7) Yasutake, M.; Koga, T.; Sakamoto, Y.; Komatsu, S.; Sako, K.;
Tatemitsu, H.; Aso, Y.; Inoue, S.; Shinmyozu, T. Submitted.
(8) (a) Kurosawa, K.; Suenaga, M.; Inazu, T.; Yoshino, T. Tetrahedron
Lett. 1982, 23, 5335. (b) Shinmyozu, T.; Hirai, Y.; Inazu, T. J. Org. Chem.
1986, 51, 1551. (c) Sasaki, H.; Kitagawa, T. Chem. Pharm. Bull. 1983, 31,
2868.
(9) An important intermediate, 6, was prepared starting from 1,3,5-
trifluorobenzene by the chloromethylation with ClCH2OCH3 in the presence
of AlCl3 in refluxing CS2 (80%), followed by the halogen exchange of the
resultant 1,3,5-tris(chloromethyl)-2,4,6-trifluorobenzene with NaBr-EtBr
1
in DMF (78%). 6: colorless crystals (CH2Cl2); H NMR (CDCl3) δ 4.48
(s, 6H, CH2Br); 19F NMR (CDCl3, C6F6) δ 47.6 (s); FAB-MS m/z 408.9
[M+]. Anal. Calcd for C9H6Br3F3: C, 26.31; H, 1.47. Found: C, 26.50; H,
1.46.
Figure 1. Electronic spectra of [33]CP 1, F1[33]Cp 2, F3[33]Cp 3,
and F6[33]CP 4 in CHCl3.
(10) (a) Hoogenboom, B. E.; Oldenziel, O. H.; van Leusen, A. M.
Organic Syntheses; Wiley: New York, 1988; Collect. Vol. 6, p 987. (b)
Possel, O.; van Leusen, A. M. Tetrahedron Lett. 1977, 4229.
(11) Selected spectroscopic data and elemental analysis for 4: colorless
crystals (hexane). This compound shows complex phase transition phe-
nomenon. The details will be reported in a full paper on this work. 1H
NMR (CDCl3) δ 2.26 (m, 6H), 2.78-2.83 (m, 12H); 19F NMR (CDCl3,
C6F6) δ 46.3 (s, 6F); FAB-MS m/z 384.1 [M+]. Anal. Calcd for C21H18F6:
C, 65.62; H, 4.72. Found: C, 65.90; H, 4.98.
reference in CHCl3. Although the longest wavelength π-π*
band (λmax) of 2 (313 nm, ꢀ 337)15 shows a slight red shift
compared with that of 1 (308 nm, ꢀ 88), the band shows a
(12) Breitenbach, J.; Vo¨gtle, F. Synthesis 1992, 41.
(13) Selected spectroscopic data and elemental analysis for 3: colorless
1
crystals (hexane); mp 109.5-111 °C; H NMR (CDCl3) δ 2.16 (m, 6H),
(14) Meno, T.; Sako, K.; Suenaga, M.; Mouri, M.; Takemura, H.;
Shinmyozu, T.; Inazu, T. Can. J. Chem. 1990, 68, 440-445.
(15) Synthesis and characterization of F1[33]CP 2 will be reported in a
full paper on this work.
2.65-2.74 (m, 12H), 6.82 (s, 3H); 19F NMR (CDCl3, C6F6) δ 45.8 (s, 3F);
FAB-MS m/z 330.2 [M+]. Anal. Calcd for C21H21F3‚0.25H2O: C, 75.37;
H, 6.48. Found: C, 75.30; H, 6.52.
1420
Org. Lett., Vol. 3, No. 10, 2001