(Phenyl)[o-(Trimethylsilyl)phenyl]iodonium Triflate
J. Am. Chem. Soc., Vol. 121, No. 50, 1999 11679
phenyl](phenyl)iodonium triflate (12): mp 128-132 °C (ether-
at room temperature for 30 min. Water was then added, and the resulting
mixture was extracted with CH2Cl2. The organic extracts were dried
over anhydrous Na2SO4 and concentrated. The residue was purified
by column chromatography on silica gel. The reaction with furan,
2-methylfuran, anthracene, and tetraphenylcyclopentadienone gave the
following products.
1
MeOH); H NMR (CDCl3) δ 0.39 (s, Me, 9 H), 2.43 (s, Me, 3 H),
7.25-8.03 (m, ArH, 8 H). Anal. Calcd for C17H20F3IO3SSi: C, 39.54;
H, 3.90. Found: C, 39.37; H, 3.90.
Preparation of [2-Methyl-6-(trimethylsilyl)phenyl](phenyl)-
iodonium Triflate (13). Similar reaction of 2,3-bis(trimethylsilyl)-
toluene with a hypervalent iodine reagent system, PhI(OAc)2/TfOH,
as described above gave 12.0 g (78%) of [2-methyl-6-(trimethylsilyl)-
phenyl](phenyl)iodonium triflate (13): mp 142-144 °C (ether-
1,4-Dihydro-1,4-epoxy-6-methylnaphthalene (21):20 0.158 g (100%);
oil; 1H NMR (CDCl3) δ 2.25 (s, Me, 3 H), 5.61 (s, CH, 1 H), 5.63 (s,
CH, 1 H), 6.70-7.08 (m, dCH and ArH, 5 H); 13C NMR (CDCl3) δ
21.1, 82.1, 82.2, 119.8, 121.5, 125.3, 134.7, 142.8, 143.2, 146.0, 149.2.
1,4-Dihydro-1,6-dimethyl-1,4-epoxynaphthalene and 1,4-dihydro-
1,7-dimethyl-1,4-epoxynaphthalene (23): 0.167 g (97%); a 1:1
1
MeOH); H NMR (CDCl3) δ 0.42 (s, Me, 9 H), 2.58 (s, Me, 3 H),
7.26-8.13 (m, ArH, 8 H). Anal. Calcd for C17H20F3IO3SSi: C, 39.54;
H, 3.90. Found: C, 39.44; H, 3.93.
1
mixture; oil; H NMR (CDCl3) δ 1.89 (s, Me x 2), 2.25 (s, Me), 2.27
Reaction of (Phenyl)[2-(trimethylsilyl)phenyl]iodonium Triflate
10 with Bu4NF in the Presence of Furan. To a solution of (phenyl)-
[2-(trimethylsilyl)phenyl]iodonium triflate 10 (0.502 g, 1.0 mmol) and
furan (0.340 g, 5.0 mmol) in CH2Cl2 (3 mL) was added dropwise a
THF solution of Bu4NF (1.0 M, 1.2 mL) at 0 °C, and the reaction
mixture was stirred at room temperature for 30 min. Then, water was
added and the resulting mixture was extracted with CH2Cl2. The organic
extracts were dried over anhydrous Na2SO4 and concentrated. The
residue was purified by column chromatography on silica gel using
CH2Cl2 as the eluent. Evaporation of the solvent gave colorless crystals
of 1,4-dihydro-1,4-epoxynaphthalene (16):26 0.144 g (100%); mp 51-
(s, Me), 5.54-5.56 (m, CH), 6.69-7.06 (m, dCH and ArH). These
isomers could not be separated purely.
9,10-Dihydro-2-methyl-9,10-o-benzenoanthracene (24):16 0.166 g
1
(62%); mp 205-206 °C; H NMR (CDCl3) δ 2.24 (s, Me, 3 H), 5.36
(s, CH, 1 H), 5.37 (s, CH, 1 H), 6.93-7.40 (m, ArH, 11 H); 13C NMR
(CDCl3) δ 21.1, 53.7, 54.1, 123.3, 123.47, 123.51, 124.6, 125.0, 125.1,
125.4, 134.7, 142.5, 145.3, 145.4, 145.5.
6-Methyl-1,2,3,4-tetraphenylnaphthalene (25): 0.351 g (88%); mp
1
217.5-220.5 °C; H NMR (CDCl3) δ 2.37 (s, Me, 3 H), 6.75-7.56
(m, ArH, 23 H); 13C NMR (CDCl3) δ 22.2, 125.9, 126.2, 126.6, 127.0,
127.5, 127.9, 130.5, 131.4, 131.7, 132.3, 135.8, 138.0, 138.2, 138.4,
139.1, 139.9, 140.8, 140.9. Anal. Calcd for C35H26: C, 94.13; H, 5.87.
Found: C, 93.94; H, 5.88.
1
55 °C; H NMR (CDCl3) δ 5.69 (s, CH 2 H), 6.94-6.96 (m, ArH, 2
H), 7.00 (s, dCH), 7.22-7.24 (m, ArH, 2 H); 13C NMR (CDCl3) δ:
82.2, 120.2, 124.9, 142.9, 148.9.
Trapping Reaction of 3-Methylbenzyne 27 Generated from 13
with Cyclic Dienes. To a solution of (phenyl)[2-methyl-6-(trimethyl-
silyl)phenyl]iodonium triflate 13 (0.516 g, 1.0 mmol) and a cyclic diene
(5.0 mmol) in CH2Cl2 (3-7 mL) was added dropwise a THF solution
of Bu4NF (1.0 M, 1.2 mL) at 0 °C, and the reaction mixture was stirred
at room temperature for 30 min. Water was then added and the resulting
mixture was extracted with CH2Cl2. The organic extracts were dried
over anhydrous Na2SO4 and concentrated. The residue was purified
by column chromatography on silica gel. The reaction with furan, 2-tert-
butylfuran, 2-methylfuran, anthracene, and tetraphenylcyclopentadi-
enone gave the following products. The regioisomers obtained in the
reaction with 2-tert-butylfuran or 2-methylfuran were determined by
the observation of NOE between the substituents.
Reaction of 10 with KF/18-Crown-6 in the Presence of Furan.
To a suspension of KF (3.0 mmol) and 18-Crown-6 (0.6 mmol) in
CH2Cl2 (3 mL) was added furan (5.0 mmol) and 10 (0.502 g, 1.0 mmol)
at room temperature. After stirring for 3 h, water was added, and the
resulting mixture was extracted with CH2Cl2. The organic extracts were
dried over anhydrous Na2SO4 and concentrated. The residue was
purified by column chromatography on silica gel using CH2Cl2 as the
eluent. Evaporation of the solvent gave 0.127 g (88%) of 16.
Trapping Reaction of Benzyne Generated from 10 with Cyclic
Dienes. To a solution of (phenyl)[2-(trimethylsilyl)phenyl]iodonium
triflate 10 (0.502 g, 1.0 mmol) and a cyclic diene (5.0 mmol) in CH2-
Cl2 (3-7 mL) was added dropwise a THF solution of Bu4NF (1.0 M,
1.2 mL) at 0 °C, and the reaction mixture was stirred at room
temperature for 30 min. Water was then added, and the resulting mixture
was extracted with CH2Cl2. The organic extracts were dried over
anhydrous Na2SO4 and concentrated. The residue was purified by
column chromatography on silica gel. The reaction with 2-methylfuran,
anthracene, tetraphenylcyclopentadienone, and 1,3-diphenylisobenzo-
furan gave the following products.
1,4-Dihydro-1,4-epoxy-5-methylnaphthalene (26): 0.158 g (100%);
1
oil; H NMR (CDCl3) δ 2.27 (s, Me, 3 H), 5.65 (s, CH, 1 H), 5.76
(s, CH, 1 H), 6.72-7.06 (m, dCH and ArH, 5 H); 13C NMR (CDCl3)
δ 18.0, 80.7, 82.4, 117.7, 124.9, 126.6, 129.8, 142.6, 143.1, 147.3,
148.6. Anal. Calcd for C11H10O: C, 83.52; H, 6.37. Found: C, 83.38;
H, 6.30.
1-Methyl-1,4-dihydro-1,4-epoxynaphthalene (17):20 0.158 g (100%);
1,4-Dihydro-1,5-dimethyl-1,4-epoxynaphthalene and 1,4-dihydro-
1,8-dimethyl-1,4-epoxynaphthalene (28):22 0.172 g (100%); a 33:67
1
oil; H NMR (CDCl3) δ 1.90 (s, Me, 3 H), 5.60 (s, CH, 1 H), 6.74-
1
7.21 (m, dCH and ArH, 6 H); 13C NMR (CDCl3) δ 15.1, 81.7, 89.3,
118.7, 119.8, 124.6, 124.9, 144.3, 145.5, 150.5, 151.3.
mixture; oil; H NMR (CDCl3) δ 1.89 (s, Me), 2.01 (s, Me), 2.27 (s,
Me), 2.34 (s, Me), 5.54 (d, J ) 1.8 Hz, CH), 5.70 (d, J ) 1.8 Hz, CH),
6.69-7.02 (m, dCH and ArH). These isomers could not be separated
purely.
9,10-Dihydro-9,10-o-benzenoanthracene (18):27 0.218 g (86%); mp
1
253-256 °C; H NMR (CDCl3) δ 5.41 (s, CH, 2 H), 6.94-7.00 (m,
ArH, 6H), 7.34-7.40 (m, ArH, 6 H); 13C NMR (CDCl3) δ 54.1, 123.6,
125.1, 145.2.
1-tert-Butyl-1,4-Dihydro-1,4-epoxy-5-methylnaphthalene and 1-tert-
butyl-1,4-dihydro-1,4-epoxy-8-methylnaphthalene:22 0.154 g (72%);
a 30:71 mixture; oil; 1H NMR (CDCl3) δ 1.20 (s, t-Bu), 1.24 (s, t-Bu),
2.22 (s, Me), 2.40 (s, Me), 5.50 (s, CH), 5.67 (s, CH), 6.69-7.18 (m,
dCH and ArH). These isomers could not be separated purely.
9,10-Dihydro-1-methyl-9,10-o-benzenoanthracene (29):21 0.204 g
1,2,3,4-Tetraphenylnaphthalene (19):28 0.432 g (100%); mp 205-
1
206 °C; H NMR (CDCl3) δ 6.80-6.89 (m, ArH, 10 H), 7.15-7.27
(m, ArH, 10 H), 7.37-7.40 (m, ArH, 2 H), 7.61-7.66 (m, ArH, 2 H);
13C NMR (CDCl3) δ 125.3, 125.8, 126.4, 126.5, 127.0, 127.5, 131.3
(2 carbons), 132.0, 138.4, 138.9, 139.6, 140.5.
1
(76%); mp 189-190 °C; H NMR (CDCl3) δ 2.50 (s, Me, 3 H), 5.39
(s, CH, 1 H); 13C NMR (CDCl3) δ 18.5, 50.3, 54.4, 121.4, 123.6, 124.8,
125.0, 125.1, 126.7, 131.8, 143.4, 145.1, 145.2, 145.6. Anal. Calcd for
C21H16: C, 93.99; H, 6.01. Found: C, 93.95; H, 5.96.
5-Methyl-1,2,3,4-tetraphenylnaphthalene (30): 0.398 g (100%);
mp 232.5-234 °C; 1H NMR (CDCl3) δ 1.86 (s, Me, 3 H), 6.63-7.46
(m, ArH, 23 H). Anal. Calcd for C35H26: C, 94.13; H, 5.87. Found:
C, 94.01; H, 5.86.
9,10-Diphenyl-9,10-dihydro-9,10-epoxyanthracene (20):19 0.346
g (100%); mp 187-188 °C; 1H NMR (CDCl3) δ 6.99-7.04 (m, ArH,
4 H), 7.32-7.68 (m, ArH, 10 H), 7.92-7.95 (m, ArH, 4 H); 13C NMR
(CDCl3) δ 90.5, 120.3, 125.6, 126.7, 128.2, 128.7, 135.1, 150.4
Trapping Reaction of 4-Methylbenzyne 22 Generated from 12
with Cyclic Dienes. To a solution of (phenyl)[4-methyl-2-(trimethyl-
silyl)phenyl]iodonium triflate 12 (0.516 g, 1.0 mmol) and a cyclic diene
(5.0 mmol) in CH2Cl2 (3-7 mL) was added dropwise a THF solution
of Bu4NF (1.0 M, 1.2 mL) at 0 °C, and the reaction mixture was stirred
Acknowledgment. We are grateful for Grants-in-Aid for
Scientific Research from the Ministry of Education, Science,
Sports and Culture, Japan.
(26) Wittig, G.; Pohmer, L. Chem. Ber. 1956, 89, 1334-1351.
(27) Wittig, G. Organic Syntheses; Wiley & Sons: New York, 1963;
Collect. Vol. IV, p 964-965.
(28) Beringer, F. M.; Huang, S. J. J. Org. Chem. 1964, 29, 445-448.
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