Synthesis, Solubility, and Reaction of Long Alkyl-Chained Hypervalent Iodine Benzyne Precursors

Article abstract of DOI:10.1246/bcsj.76.2175

Long-chained hypervalent iodine benzyne precursors bearing ethyl, butyl, hexyl, octyl, decyl, dodecyl, and tetradecyl groups were synthesized, respectively. As the alkyl chain of the benzyne precursors is lengthened, the solubility in nonpolar organic solvents and the yield of the benzyne adduct with furan gradually increases.

Full text of DOI:10.1246/bcsj.76.2175

Ó 2003 The Chemical Society of Japan
Bull. Chem. Soc. Jpn., 76, 2175–2178 (2003) 2175
Synthesis, Solubility, and Reaction of Long Alkyl-Chained Hypervalent
Iodine Benzyne Precursors
ꢀ;y
Takayoshi Abe, Teizo Yamaji, and Tsugio Kitamura
Department of Applied Chemistry, Faculty of Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581
yDepartment of Chemistry and Applied Chemistry, Faculty of Science and Engineering, Saga University,
Honjo-machi, Saga 840-8502
Received May 26, 2003; E-mail: kitamura@cc.saga-u.ac.jp
Long-chained hypervalent iodine benzyne precursors bearing ethyl, butyl, hexyl, octyl, decyl, dodecyl, and tetra-
decyl groups were synthesized, respectively. As the alkyl chain of the benzyne precursors is lengthened, the solubility
in nonpolar organic solvents and the yield of the benzyne adduct with furan gradually increases.
Benzyne is one of the important reactive intermediates in or-
ganic chemistry, and has been extensively applied to mechanis-
tic studies and syntheses of functionalized materials.1 Recent-
ly, we reported that (phenyl)[2-(trimethylsilyl)phenyl]iodo-
nium triflate (1a) is an excellent benzyne precursor.2 The reac-
tion of [2-(trimethylsilyl)phenyl]iodonium triflate 1a with
tetrabutylammonium fluoride generates benzyne quantitatively
under mild conditions (room temperature and neutral condi-
tions) and affords a benzyne adduct in the presence of a trap-
ping agent in high yield, as shown in Scheme 1. This method-
Fig. 1.
ology can be applied to the generation of various types of
strained species, such as a cyclic alkyne,3 didehydrohetero-
cycles,4 didehydronaphthalene,5 and didehydrocarboranes.6
Also, this benzyne precursor 1a has been used satisfactorily
in the reaction of benzyne with thioketones that are very un-
stable, and are not tolerable under alkaline conditions.7
In spite of such advantages, this benzyne precursor 1a has a
low solubility in most organic solvents (hexane, diethyl ether,
benzene, toluene, THF, and so on). Accordingly, the choice
of solvents is limited to polar solvents, such as dichloromethane
and MeCN.
In order to improve the solubility of the benzyne precursor
1a, we prepared (4-dodecylphenyl)[2-(trimethylsilyl)phen-
yl]iodonium triflate (1b) and the tetradecyl derivative (1c),8
as described in Fig. 1. These benzyne precursors, 1b and 1c,
dissolved even in organic solvents of low polarity, such as di-
ethyl ether, THF, benzene, and toluene. The reaction of ben-
zyne with an appropriate trapping agent in the above solvent
gave a benzyne adduct in high yield. Surprisingly, even in
the lowest polar solvent, hexane, the trapping of benzyne pro-
ceeded efficiently. Therefore, the introduction of a long alkyl
chain on the benzyne precursor 1a improves the solubility
and enable to the use of solvents of low polarity.
In this study, we synthesized various hypervalent iodine ben-
zyne precursors bearing alkyl chains of different lengths. We
examined the relation between the solubility and the trapping
efficiency of benzyne in the reaction in low polar solvents, tol-
uene or hexane.
Results and Discussion
Synthesis of Hypervalent Iodine Benzyne Precursors 1
Bearing Various Lengths of Alkyl Chain. The synthetic
procedure for benzyne precursors 1d–1h is outlined in
Scheme 2. Diazotization of alkyl-substituted anilines 2 was
conducted with sodium nitrite and hydrochloric acid, followed
by a treatment with potassium iodide to give 1-alkyl-4-iodo-
benzenes 3. The crude 1-alkyl-4-iodobenzenes 3 were purified
by column chromatography on silica gel.
The subsequent oxidation of 1-alkyl-4-iodobenzenes 3 was
conducted with peracetic acid (30% in acetic acid) in ethyl ace-
tate at 40 ꢁC. Extraction with CH2Cl2 gave crude 1-alkyl-4-(di-
acetoxyiodo)benzenes 4. The crude 1-alkyl-4-(diacetoxyiodo)-
benzenes 4 were used for an aryliodination reaction without
Scheme 1.
Published on the web November 15, 2003; DOI 10.1246/bcsj.76.2175

2176 Bull. Chem. Soc. Jpn., 76, No. 11 (2003)
Hypervalent Iodine Benzyne Precursors
Table 2. Solubility of Hypervalent Iodine Benzyne Precur-
sors 1
Benzyne
Solubility/wt %a)
Hexane/THF (82:18)
precursor 1
Toluene
b)
b)
b)
b)
1a: n ¼ 0
1d: n ¼ 2
1e: n ¼ 4
1f: n ¼ 6
1g: n ¼ 8
1h: n ¼ 10
1b: n ¼ 12
1c: n ¼ 14
—
—
—
—
—
b)
2.4
45.6
0.42
0.83
7.52
37.09
46.45
61.4
187.6
c)
—
—
c)
a) Solubility (wt %) of 1 (g) against a solvent (g). b) Difficult
to measure because of the insolubility. c) Freely soluble.
Table 3. Trapping Reaction of Benzyne with Furan
Scheme 2.
Table 1. Isolated Yield of Hypervalent Iodine Benzyne Pre-
cursors 1
Entry
Benzyne precursor 1
Isolated yield/%a)
1
2
3
4
5
1d: n ¼ 2
1e: n ¼ 4
1f: n ¼ 6
1g: n ¼ 8
1h: n ¼ 10
50
40
46
30
35
Entry
Benzyne
Sovent
Isolated yield/%
precursor 1
5
3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1a: n ¼ 0
1d: n ¼ 2
1e: n ¼ 4
1f: n ¼ 6
1g: n ¼ 8
1h: n ¼ 10
1b: n ¼ 12
1c: n ¼ 14
1a: n ¼ 0
1d: n ¼ 2
1e: n ¼ 4
1f: n ¼ 6
1g: n ¼ 8
1h: n ¼ 10
1b: n ¼ 12
1c: n ¼ 14
Toluene
64
71
—
75
a) Based on 3.
73
73
98
99
further purification.
1-Alkyl-4-(diacetoxyiodo)benzenes 4 were treated with tri-
fluoromethanesulfonic acid (TfOH) in CH2Cl2 at ꢂ20 ꢁC,
and then reacted with 1,2-bis(trimethylsilyl)benzene to give
the corresponding (4-alkylphenyl)[2-(trimethylsilyl)phenyl]-
iodonium triflates 1 as crystals. The isolated yields of benzyne
precursors 1 are given in Table 1.
We then examined the solubility of the prepared benzyne
precursors 1 in toluene or hexane. In the case of hexane as a
solvent, a mixture (v/v 82:18) of hexane and THF was em-
ployed, since the addition of a THF solution of Bu4NF to a hex-
ane solution led to an 82:18 ratio in the reaction. The solubility
of each hypervalent iodine benzyne precursꢁors 1 is expressed in
wt % against the employed solvent at 20 C. The results are
given in Table 2. Particularly, dodecylphenyl- and tetradecyl-
phenyl-substituted benzyne precursors, 1b and 1c, dissolved
freely in toluene, while phenyl- and ethylphenyl-substituted
ones, 1a and 1d, did not dissolve. Benzyne precursors 1 did
not dissolve in hexane, but become soluble in a mixed solvent
of hexane and THF (v/v 82:18) in the cases of longer alkyl
chains (n > 10).
80
96
82
91
86a)
82a)
61
92a)
100a)
—
Hexane
66
63
78
96
70
72
91
96
72
94
87a)
89a)
93a)
90a)
a) Ref. 8.
precursor 1 and furan in toluene or in hexane. None of the ben-
zyne precursors 1 dissolved in hexane, but the benzyne precur-
sors having alkyl groups longer than the butyl group dissolved
in toluene completely. The benzyne adduct, 1,4-dihydro-1,4-
epoxynaphthalene (5), was isolated by column chromatography
together with 1-alkyl-4-iodobenzene 3. The results are given in
Table 3.
Trapping Reaction of Benzyne in Low Polar Solvents. A
trapping reaction of benzyne was conducted by adding a solu-
tion of Bu4NF in THF to a solution or suspension of a benzyne
The yield of benzyne adduct 5 increased with increasing the
length of the alkyl chain. This result is consistent with an im-

T. Abe et al.
Bull. Chem. Soc. Jpn., 76, No. 11 (2003) 2177
MHz, CDCl3) ꢀ 0.91 (t, J ¼ 7:2 Hz, 3H, Me), 1.27–1.39 (m, 2H,
CH2), 1.51–1.61 (m, 2H, CH2), 2.55 (t, J ¼ 7:7 Hz, 2H, CH2),
6.93 (d, J ¼ 8:4 Hz, 2H, ArH), 7.58 (d, J ¼ 8:4 Hz, 2H, ArH).
13C NMR (75 Hz, CDCl3) ꢀ 13.9, 22.2, 33.4, 35.1, 90.5, 130.5,
137.2, 142.5.
provement in the solubility of benzyne precursors 1. Even in
hexane, the benzyne adduct was obtained in good yields. When
a THF solution of Bu4NF is used as a desilylating agent, the sol-
vent composition leads to a mixture (v/v 82:18) of hexane and
THF under the reaction conditions. As a result, the solubility of
benzyne precursors 1 is improved. Even in the cases of unsub-
stituted and short alkyl group-substituted phenyl groups, ben-
zyne adduct 5 was obtained in good yields. Such benzyne pre-
cursors 1 did not dissolve, even in a mixed solvent of hexane
and THF. Therefore, in these cases the reaction may proceed
even in the interface between solid and liquid. Although, in
a previous study,8 we did not conduct a reaction of the unsub-
stituted benzyne precursor 1a in nonpolar solvents, we realized
that the generation and reaction of benzyne effectively proceed-
ed even in nonpolar solvents, such as hexane and toluene. This
fact, therefore, indicates that hypervalent iodine benzyne pre-
cursors 1 have a high reactivity toward a fluoride source.
1-Hexyl-4-iodobenzene (3f):11
Yield 56%. 1H NMR (300
MHz, CDCl3) ꢀ 0.88 (t, J ¼ 6:6 Hz, 3H, Me), 1.28 (br s, 6H,
CH2), 1.52–1.59 (m, 2H, CH2), 2.54 (t, J ¼ 7:6 Hz, 2H, CH2),
6.93 (d, J ¼ 8:4 Hz, 2H, ArH), 7.58 (d, J ¼ 8:4 Hz, 2H, ArH).
13C NMR (75 Hz, CDCl3) ꢀ 14.1, 22.6, 28.8, 31.3, 31.6, 35.4,
90.5, 130.5, 137.2, 142.5.
1-Iodo-4-octylbenzene (3g): Yield 54%. 1H NMR (300 MHz,
CDCl3) ꢀ 0.87 (t, J ¼ 6:8 Hz, 3H, Me), 1.26 (br s, 10H, CH2),
1.52–1.61 (m, 2H, CH2), 2.53 (t, J ¼ 7:7 Hz, 2H, CH2), 6.91 (d,
J ¼ 8:4 Hz, 2H, ArH), 7.57 (d, J ¼ 8:4 Hz, 2H, ArH). 13C NMR
(75 Hz, CDCl3) ꢀ 14.1, 22.6, 29.2 (two carbons), 29.4, 31.3, 31.8,
35.4, 90.5, 130.5, 137.2, 142.5. Anal. Calcd for C14H21I: C, 53.17;
H, 6.69%. Found: C, 53.30; H, 6.71%.
1-Decyl-4-iodobenzene (3h).12 Yield 58%. 1H NMR (300
MHz, CDCl3) ꢀ 0.88 (t, J ¼ 6:8 Hz, 3H, Me), 1.25 (br s, 14H,
CH2), 1.52–1.59 (m, 2H, CH2), 2.53 (t, J ¼ 7:8 Hz, 2H, CH2),
6.93 (d, J ¼ 8:4 Hz, 2H, ArH), 7.58 (d, J ¼ 8:4 Hz, 2H, ArH).
13C NMR (75 Hz, CDCl3) ꢀ 14.1, 22.7, 29.2, 29.3, 29.4, 29.6
(two carbons), 31.3, 31.9, 35.4, 90.5, 130.6, 137.2, 142.5.
General Procedure for Preparation of 1-Alkyl-4-(diacet-
oxyiodo)benzenes (4). To a solution of a 1-alkyl-4-iodobenzene
3 (2.0 mmol) in ethyl acetate (10 cm3) was added dropwise a solu-
tion of peracetic acid in acetic acid (30%, 8 cm3) at 0 ꢁC. The mix-
ture was stirred at 40 ꢁC for 20 h. The product was extracted with
CH2Cl2, washed with water, and dried over anhydrous sodium
sulfate. The solvent was evaporated under reduced pressure to give
a crude (diacetoxyiodo)benzene derivative 4 in 79–86% yield.
Although the crude (diacetoxyiodo)benzenes 4 contained a small
amount of inseparable impurities, the 1H NMR spectra showed that
they were pure enough to be used for the subsequent reaction. Ac-
cordingly, the crude products were used to prepare benzyne precur-
sors 1.
1-Ethyl-4-(diacetoxyiodo)benzene (4d): 1H NMR (300 MHz,
CDCl3) ꢀ 1.27 (t, J ¼ 6:9 Hz, 3H, Me), 2.01 (s, 6H, Me), 2.74 (q,
J ¼ 6:9 Hz, 2H, CH2), 7.32 (d, J ¼ 8:7 Hz, 2H, ArH), 8.00 (d, J ¼
8:7 Hz, 2H, ArH).
1-Butyl-4-(diacetoxyiodo)benzene (4e): 1H NMR (300 MHz,
CDCl3) ꢀ 0.94 (t, J ¼ 7:2 Hz, 3H, Me), 1.34–1.42 (m, 2H, CH2),
1.57–1.67 (m, 2H, CH2), 2.01 (s, 6H, Me), 2.68 (t, J ¼ 7:8 Hz,
2H, CH2), 7.30 (d, J ¼ 8:4 Hz, 2H, ArH), 7.98 (d, J ¼ 8:4 Hz,
2H, ArH).
1-(Diacetoxyiodo)-4-hexylbenzene (4f): 1H NMR (300 MHz,
CDCl3) ꢀ 0.89 (t, J ¼ 6:8 Hz, 3H, Me), 1.32 (br s, 6H, CH2), 1.56–
1.65 (m, 2H, CH2), 2.01 (s, 6H, Me), 2.67 (t, J ¼ 7:8 Hz, 2H, CH2),
7.29 (d, J ¼ 8:4 Hz, 2H, ArH), 7.98 (d, J ¼ 8:4 Hz, 2H, ArH).
1-(Diacetoxyiodo)-4-octylbenzene (4g): 1H NMR (300 MHz,
CDCl3) ꢀ 0.88 (t, J ¼ 6:8 Hz, 3H, Me), 1.27 (br s, 10H, CH2),
1.58–1.65 (m, 2H, CH2), 2.01 (s, 6H, Me), 2.67 (t, J ¼ 7:8 Hz,
2H, CH2), 7.29 (d, J ¼ 8:4 Hz, 2H, ArH), 7.98 (d, J ¼ 8:4 Hz,
2H, ArH).
1-Decyl-4-(diacetoxyiodo)benzene (4h): 1H NMR (300 MHz,
CDCl3) ꢀ 0.88 (t, J ¼ 6:8 Hz, 3H, Me), 1.26 (br s, 14H, CH2),
1.58–1.65 (m, 2H, CH2), 2.02 (s, 6H, Me), 2.67 (t, J ¼ 7:8 Hz,
2H, CH2), 7.30 (d, J ¼ 8:4 Hz, 2H, ArH), 7.98 (d, J ¼ 8:4 Hz,
2H, ArH).
Conclusion
We have demonstrated the synthesis, solubility, and reaction
of hypervalent iodine benzyne precursors having various alkyl
chains. As the alkyl chain of benzyne precursor 1 is length-
ened, the solubility in a solvent of low polarity increases.
The improvement in the solubility gives a better yield of ben-
zyne adduct 5. Therefore, the long-chained benzyne precursors
1 are widely available in synthetic and mechanistic studies us-
ing a less-polar organic solvent.
Experimental
General. Melting points were measured with a Yanaco melting
apparatus, and are uncorrected. NMR spectra were taken with a
JEOL JNM AL 300 spectrometer. Elemental analyses were con-
ducted by the Service Center of the Elementary Analysis of Organ-
ic Compounds, Faculty of Science, Kyushu University. Phenyl[2-
(trimethylsilyl)phenyl]iodonium triflate (1a),2 (4-dodecylphen-
yl)[2-(trimethylsilyl)phenyl]iodonium triflate (1b),8 and (4-tetra-
decylphenyl)[2-(trimethylsilyl)phenyl]iodonium triflate (1c)8 were
prepared according to the literature.
General Procedure for Preparation of 1-Alkyl-4-iodoben-
zenes 3. To a suspension of a 4-alkylaniline 2 (10 mmol) in
H2O (20 cm3) was added aqueous HCl (10 mol dmꢂ3, 1.0 cm3)
at room temperature. After the mixture was cooled to 0 ꢁC, an
HCl solution (10 mol dmꢂ3, 1.1 cm3) was added, and then a solu-
tion of NaNO2 (0.69 g, 10 mmol) in H2O (5 cm3) was slowly added
dropwise. To the resulting arenediazonium chloride solution was
added a solution of KI (1.66 g, 10 mmol) in H2O (5 cm3)
dropwise. The reaction mixture was heated with stirring at 40
ꢁC until an oil was completely separated from the solution. After
the addition of aqueous sodium thiosulfate to decolorize, the prod-
uct was extracted with ether. The ethereal extract was washed with
water and brine, dried over anhydrous sodium sulfate, and concen-
trated under reduced pressure. The residual oil was purified by col-
umn chromatography on silica gel. Elution with hexane gave a 1-
alkyl-4-iodobenzene 3 as a colorless oil.
1-Ethyl-4-iodobenzene (3d):9
Yield 65%. 1H NMR (300
MHz, CDCl3) ꢀ 1.21 (t, J ¼ 7:7 Hz, 3H, Me), 2.59 (q, J ¼ 7:7
Hz, 2H, CH2), 6.95 (d, J ¼ 8:4 Hz, 2H, ArH), 7.59 (d, J ¼ 8:4
Hz, 2H, ArH). 13C NMR (75 Hz, CDCl3) ꢀ 15.4, 28.4, 90.5,
130.0, 137.3, 143.8.
General Procedure for Preparation of Hypervalent Iodine
Benzyne Precursors 1. To a solution of the crude 1-alkyl-4-(di-
1-Butyl-4-iodobenzene (3e):10
Yield 56%. 1H NMR (300

2178 Bull. Chem. Soc. Jpn., 76, No. 11 (2003)
Hypervalent Iodine Benzyne Precursors
acetoxyiodo)benzene 4 (1.65 mmol) prepared as mentioned above
in CH2Cl2 (10 cm3) was added dropwise TfOH (0.29 cm3, 0.32
mmol) at ꢂ20 ꢁC. The solution was stirred at ꢂ20 ꢁC for 30
min. At that temperature, 1,2-bis(trimethylsilyl)benzene (0.366
g, 1.65 mmol) was added and the reaction mixture was stirred at
ꢂ20 ꢁC and at room temperature for 15 min. The reaction mixture
was washed with water and dried over anhydrous sodium sulfate.
The solvent was evaporated under reduced pressure to give light-
brown crystals or oil. Crystallization from ether or hexane afford-
ed benzyne precursor 1. The isolated yield of 1 in Table 1 was cal-
culated based on 1-alkyl-4-iodobenzene 3. The contamination of 4
with impurities may cause a decrease in the yield of benzyne pre-
cursors 1. An analytically pure sample was obtained by recrystal-
lization from a mixed solvent of CH2Cl2 and hexane or CH2Cl2
and ether.
General Procedure for Trapping Reaction of Benzyne with
Furan. To a solution of benzyne precursor 1 (0.5 mmol) and furan
(0.170 g, 2.5 mmol) in toluene or hexane (2 cm3) was added drop-
ꢁ
wise a THF solution of Bu4NF (1.0 mol dmꢂ3, 0.6 cm3) at 0 C.
The reaction mixture was stirred at room temperature for 30 min.
The solvent was evaporated and water was added to the residue.
The product was extracted with CH2Cl2. The organic extract
was dried over anhydrous sodium sulfate and concentrated. The
residue was submitted to column chromatography on silica gel.
Elution with CH2Cl2 and hexane gave 1,4-dihydro-1,4-epoxynaph-
thalene (5).
13
ꢁ
1,4-Dihydro-1,4-epoxynaphthalene (5). Mp 51–55 C (lit.
ꢁ
mp 55–56 C). 1H NMR (300 MHz, CDCl3) ꢀ 5.72 (s, 2H, CH),
6.95–7.00 (m, 2H, ArH), 7.03 (s, 2H, =CH), 7.23–7.27 (m, 2H,
ArH). 13C NMR (75 Hz, CDCl3) ꢀ 82.3, 120.2, 125.0, 143.0,
149.0.
(4-Ethylphenyl)[2-(trimethylsilyl)phenyl]iodonium Triflate
Isolated yield 50%. Mp 134–135 ꢁC. 1H NMR (300
(1d):
MHz, CDCl3) ꢀ 0.43 (s, 9H, Me), 1.21 (t, J ¼ 7:6 Hz, 3H, Me),
2.67 (q, J ¼ 7:6 Hz, 2H, CH2), 7.26–8.12 (m, 8H, ArH). 13C NMR
(75 Hz, CDCl3) ꢀ 0.06, 14.9, 28.4, 110.2, 121.9, 132.0, 132.1,
133.3, 133.5, 138.3, 138.6, 146.9, 149.3. Anal. Calcd for
C18H22F3IO3SSi: C, 40.76; H, 4.18%. Found: C, 40.61; H, 4.16%.
(4-Butylphenyl)[2-(trimethylsilyl)phenyl]iodonium Triflate
References
1
a) R. W. Hoffmann, ‘‘Dehydrobenzene and Cycloalkynes,’’
Academic Press, New York (1968). b) T. L. Gilchrist, ‘‘The Chem-
istry of Functional Groups, Supplement C,’’ ed by S. Patai and Z.
Rappoport, Wiley, Chichester (1983), Chapter 11. c) H. Hart, ‘‘The
Chemistry of Triple-Bonded Functional Groups, Supplement C2,’’
ed by S. Patai, Wiley, Chichester (1994), Chapter 18.
(1e):
Isolated yield 40%. Mp 110–111 ꢁC. 1H NMR (300
MHz, CDCl3) ꢀ 0.43 (s, 9H, Me), 0.90 (t, J ¼ 7:4 Hz, 3H, Me),
1.28–1.38 (m, 2H, CH2), 1.51–1.61 (m, 2H, CH2), 2.62 (q, J ¼
7:7 Hz, 2H, CH2), 7.24–8.12 (m, 8H, ArH). 13C NMR (75 Hz,
CDCl3) ꢀ 0.05, 13.8, 22.1, 33.0, 35.1, 110.1, 121.8, 132.1, 132.5,
133.3, 133.4, 138.3, 138.6, 146.9, 148.1. Anal. Calcd for
C20H26F3IO3SSi: C, 43.01; H, 4.69%. Found: C, 42.98; H, 4.70%.
(4-Hexylphenyl)[2-(trimethylsilyl)phenyl]iodonium Triflate
2
a) T. Kitamura and M. Yamane, J. Chem. Soc., Chem. Com-
mun., 1995, 1211. b) T. Kitamura, M. Yamane, K. Inoue, M.
Todaka, N. Fukatsu, Z. Meng, and Y. Fujiwara, J. Am. Chem.
Soc., 121, 11674 (1999). c) T. Kitamura, M. Todaka, and Y.
Fujiwara, Org. Synth., 78, 104 (2002).
3
T. Kitamura, M. Kotani, T. Yokoyama, Y. Fujiwara, and K.
Hori, J. Org. Chem., 64, 680 (1999).
a) X.-S. Ye, W.-K. Li, and H. N. C. Wong, J. Am. Chem.
ꢁ
(1f): Isolated yield 46%. Mp 99–100 C. 1H NMR (300 MHz,
CDCl3) ꢀ 0.43 (s, 9H, Me), 0.87 (t, J ¼ 6:6 Hz, 3H, Me), 1.27
(br s, 6H, CH2), 1.52–1.59 (m, 2H, CH2), 2.62 (q, J ¼ 7:8 Hz,
2H, CH2), 7.24–8.09 (m, 8H, ArH). 13C NMR (75 Hz, CDCl3) ꢀ
0.09, 14.0, 22.5, 28.8, 30.9, 31.5, 35.5, 110.2, 121.9, 132.1,
132.6, 133.3, 133.4, 138.3, 138.6, 147.1, 148.2. Anal. Calcd for
C22H30F3IO3SSi: C, 45.05; H, 5.16%. Found: C, 45.15; H, 5.17%.
(4-Octylphenyl)[2-(trimethylsilyl)phenyl]iodonium Triflate
4
Soc., 118, 2511 (1996). b) X.-S. Ye and H. N. C. Wong, J. Org.
Chem., 62, 1940 (1997). c) J.-H. Liu, H.-W. Chan, F. Xue, G.-G.
Wang, T. C. W. Mak, and H. N. C. Wong, J. Org. Chem., 64,
1630 (1999).
5 T. Kitamura, N. Fukatsu, and Y. Fujiwara, J. Org. Chem.,
63, 8579 (1998).
ꢁ
(1g): Isolated yield 30%. Mp 90–91 C. 1H NMR (300 MHz,
6 J. Jeon, T. Kitamura, B.-W. Yoo, S. O. Kang, and J. Ko,
Chem. Commun., 2001, 2110.
CDCl3) ꢀ 0.43 (s, 9H, Me), 0.87 (t, J ¼ 6:8 Hz, 3H, Me), 1.25
(br s, 10H, CH2), 1.54–1.60 (m, 2H, CH2), 2.62 (q, J ¼ 7:8 Hz,
2H, CH2), 7.24–8.08 (m, 8H, ArH). 13C NMR (75 Hz, CDCl3) ꢀ
0.09, 14.0, 22.6, 29.1, 29.3, 30.9, 31.8, 35.5, 110.2, 121.9, 132.1,
132.6, 133.3, 133.4, 138.3, 138.6, 147.1, 148.2. Anal. Calcd for
C24H34F3IO3SSi: C, 46.90; H, 5.58%. Found: C, 46.75; H, 5.55%.
(4-Decylphenyl)[2-(trimethylsilyl)phenyl]iodonium Triflate
7
a) K. Okuma, T. Yamamoto, T. Shirokawa, T. Kitamura,
and Y. Fujiwara, Tetrahedron Lett., 37, 8883 (1996). b) K. Okuma,
K. Shiki, and K. Shioji, Chem. Lett., 1998, 79. c) K. Okuma, K.
Shiki, S. Sonoda, Y. Koga, K. Shioji, T. Kitamura, and Y.
Fujiwara, Bull. Chem. Soc. Jpn., 73, 155 (2000).
8 T. Kitamura, T. Abe, Y. Fujiwara, and T. Yamaji, Synthesis,
2003, 213.
ꢁ
(1h): Isolated yield 35%. Mp 88–89 C. 1H NMR (300 MHz,
CDCl3) ꢀ 0.43 (s, 9H, Me), 0.87 (t, J ¼ 6:6 Hz, 3H, Me), 1.24
(br s, 14H, CH2), 1.54–1.59 (m, 2H, CH2), 2.61 (q, J ¼ 7:6 Hz,
2H, CH2), 7.23–8.10 (m, 8H, ArH). 13C NMR (75 Hz, CDCl3) ꢀ
0.06, 14.1, 22.6, 29.1, 29.3 (two carbons), 29.5 (two carbons),
30.9, 31.8, 35.5, 110.2, 121.8, 132.1, 132.5, 133.3, 133.4, 138.3,
138.6, 147.0, 148.1. Anal. Calcd for C26H38F3IO3SSi: C, 48.59;
H, 5.96%. Found: C, 48.10; H, 5.87%.
9
Beilstein, 5, 357e.
10 H. Kouzai, T. Masuda, and T. Higashimura, J. Polym. Sci.,
Part A: Polym. Chem., 32, 2523 (1994).
11 J. Frahn and A. D. Schlueter, Synthesis, 1997, 1301.
12 W. B. Wan and M. M. Haley, J. Org. Chem., 66, 3893
(2001).
13 G. Wittig and L. Pohmer, Chem. Ber., 29, 1334 (1956).