Generation of magnesium carbenoids from 1-chloroalkyl phenyl sulfoxides with a Grignard reagent and applications to alkylation and olefin synthesis

Article abstract of DOI:10.1016/j.tet.2004.04.063

Treatment of 1-chloroalkyl phenyl sulfoxides with a Grignard reagent at low temperature gave magnesium carbenoids in quantitative yields. The generated magnesium carbenoids were found to be stable at lower than -60°C for long periods of time and are reactive with Grignard reagents to give alkylated products. The reaction of the generated magnesium carbenoids with various kinds of lithium α-sulfonyl carbanions gave olefins with carbon-carbon bond-formation in good to high yields. This method offers a good way for the preparation of olefins. The scope and limitations of the above-mentioned reactions are described.

Full text of DOI:10.1016/j.tet.2004.04.063

Tetrahedron 60 (2004) 5453–5460
Generation of magnesium carbenoids from 1-chloroalkyl phenyl
sulfoxides with a Grignard reagent and applications to alkylation
and olefin synthesis
*
Tsuyoshi Satoh, Atsushi Kondo and Jun Musashi
Department of Chemistry, Faculty of Science, Tokyo University of Science, Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan
Received 5 April 2004; accepted 20 April 2004
Abstract—Treatment of 1-chloroalkyl phenyl sulfoxides with a Grignard reagent at low temperature gave magnesium carbenoids in
quantitative yields. The generated magnesium carbenoids were found to be stable at lower than 260 8C for long periods of time and are
reactive with Grignard reagents to give alkylated products. The reaction of the generated magnesium carbenoids with various kinds of lithium
a-sulfonyl carbanions gave olefins with carbon–carbon bond-formation in good to high yields. This method offers a good way for the
preparation of olefins. The scope and limitations of the above-mentioned reactions are described.
q 2004 Elsevier Ltd. All rights reserved.
New development of carbon–carbon bond-forming reac-
tions is essential in synthetic organic chemistry and
innumerable reactions have been reported.1 Carbenes and
carbenoids are known to be highly reactive intermediates
and often have been recognized to be difficult to control in
reactions;2 however, this recognition is not always correct.
Recently, many interesting reactions using metal carbenes
have been reported.3
In continuation of our interest in the generation of
magnesium carbenoids and their application in new
synthetic methods, we recently investigated a generation
of a simple magnesium carbenoids 2 from 1-chloroalkyl
phenyl sulfoxides 1 with a Grignard reagent. The properties
and alkylation of the generated magnesium carbenoids 2
with several Grignard reagents to give alkanes 3 are
reported. A successful application of the reaction of the
carbenoids 2 with lithium a-sulfonyl carbanions 4 to give
olefins 5 in good to high yields is also described (Scheme 1).
Recently, we have reported a new method for generation of
magnesium carbenoids and magnesium alkylidene carben-
oids,4 magnesium cyclopropylidenes,5 based on sulfoxide–
magnesium exchange reaction6 and application of the
carbenoids in carbon–carbon bond-formation. In our
study, we found that the generated magnesium carbenoids
are relatively highly stable compared with the correspond-
ing lithium carbenoids and could be used as a useful
intermediate in organic synthesis.7
1. Results and discussion
1.1. Generation of the magnesium carbenoids and their
stability and the reactivity with Grignard reagents
First, 1-chloro-3-(4-methoxyphenyl)propyl phenyl sulfoxide
Scheme 1.
Keywords: Magnesium carbenoid; Sulfoxide; Sulfoxide–magnesium exchange; Olefin; Sulfone.
*
Corresponding author. Tel.: þ81-3-5228-8272; fax: þ81-3-3235-2214; e-mail address: tsatoh@ch.kagu.tus.ac.jp
0040–4020/$ - see front matter q 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2004.04.063

5454
T. Satoh et al. / Tetrahedron 60 (2004) 5453–5460
Scheme 2.
1a was selected as the representative example of the
1-chloroalkyl phenyl sulfoxide in this study and was
synthesized from an alcohol 6 in three steps in 92% overall
yield (Scheme 2). It is interesting to note that, although 1a
has two stereogenic centers, one isomer was obtained
predominantly (over 95%) as a crystalline compound. This
result indicated that the chlorination of the sulfoxide
proceeded in a highly stereoselective manner. The recrys-
tallized pure material 1a was used throughout this study.
This sulfoxide 1a was treated with 3 equiv. of a Grignard
reagent8 at 280 8C for 10 min, and the generated mag-
nesium carbenoid 7 was reacted with H2O or CD3OD to give
chloroalkane 8a9 and 8b. The results are summarized in
Table 1.
this reaction was quenched with CD3OD, deuterated
chloride 8b was obtained and the deuterium incorporation
was found to be perfect (entries 2–4). tert-Butylmagne-
sium chloride did not react at all with 1a under these
conditions (entry 5). Almost no reaction was observed
with benzylmagnesium chloride and phenylmagnesium
chloride (entries 6 and 7).
Entries 8–14 show the results of the reaction of 1a with
i-PrMgCl under various temperature and time. When this
reaction was carried out at 270 8C or at 260 8C and the
reaction mixture was allowed to stand for 10 or 30 min, and
the reaction was quenched with CD3OD, the yields of 8b
and the deuterium incorporation were found to be almost the
same (entries 8–11). Even when this reaction was carried
out at 250 8C for 10 min, the yield of 8b was found to be
high (entry 12); however, upon standing for 30 min, slight
decomposition of the carbenoid 7 was observed (entry 13).
The yield of 8b was markedly diminished when this reaction
was carried out at 240 8C (entry 14). From these results, we
concluded that the generated magnesium carbenoid 7 is
stable at lower than 260 8C for over 30 min.
Among the Grignard reagents examined, only ethylmag-
nesium chloride, isopropylmagnesium chloride, and
cyclohexylmagnesium chloride were found to be highly
effective for the sulfoxide–magnesium exchange reaction
(entries 2–4). Methylmagnesium chloride worked; how-
ever, under these conditions, half of the starting material
was recovered from the reaction mixture (entry 1). When
Table 1. Generation of magnesium carbenoid 7 from 1a and quenching with water or deuterio methanol
Entry
R (RMgCl)
Conditions
8
Yield (%)
1
2
3
CH3
CH3CH2
(CH3)2CH
280 8C, 10 min
280 8C, 10 min
280 8C, 10 min
8a
8b
8b
44
91a
91a
4
280 8C, 10 min
8b
89a
5
6
7
8
(CH3)3C
PhCH2
Ph
(CH3)2CH
(CH3)2CH
(CH3)2CH
(CH3)2CH
(CH3)2CH
(CH3)2CH
(CH3)2CH
280 8C, 10 min
280 8C, 10 min
280 8C, 10 min
270 8C, 10 min
270 8C, 30 min
260 8C, 10 min
260 8C, 30 min
250 8C, 10 min
250 8C, 30 min
240 8C, 30 min
No reaction
8a
8a
8b
8b
8b
8b
8b
8b
8b
Trace
Trace
92a
9
92a
10
11
12
13
14
89a
87a
89a
76a
51a
a
Deuterium incorporation was over 99%.

T. Satoh et al. / Tetrahedron 60 (2004) 5453–5460
Table 2. Treatment of 1-chloroalkyl phenyl sulfoxide 1a with excess Grignard reagent
5455
Entry
RMgX
Conditions
9
Yield (%)
1
2
3
4
CH3CH2MgCl
CH3(CH2)4CH2MgBr
(CH3)2CHMgCl
280 to 230 8C, 110 min
278 to 230 8C, 85 min
280 to 230 8C, 110 min
278 to 230 8C, 85 min
9a
9b
9c
9d
80
87
87
69
5
6
278 to 230 8C, 85 min
275 to 230 8C, 85 min
278 to 230 8C, 85 min
9e
9f
94
75
0a
7
(CH3)3CMgCl
a
The starting material 1a was recovered.
1.2. Alkylation of the generated magnesium carbenoids
with excess Grignard reagent
1.3. Olefination of the magnesium carbenoids generated
from 1-chloroalkyl phenyl sulfoxides with lithium
a-sulfonyl carbanions
In this study, we found that the reaction of 1a with excess
Grignard reagents, with warming the reaction, gave
alkyated products 9 (see Table 2).10 The mechanism of
this reaction is thought to be the nucleophilic addition of the
Grignard reagent to the carbon of the magnesium carbenoid
7, which has an electrophilic nature. Both primary alkyl
Grignard reagents and secondary alkyl Grignard reagents
gave good yields of the alkylated products 9 (Table 2;
entries 1–6). Interestingly, the Grignard reagents having a
cyclic alkyl group gave 9 in good yields (entries 5 and 6).
Even an acyclic secondary alkyl Grignard reagent gave
good yield of the adduct (entry 4). tert-Butylmagnesium
chloride did not react at all with 1a even at 230 8C (entry 7).
Based on the experiences described above, we studied
the reaction of the magnesium carbenoids 2, generated from
1-chloroalkyl phenyl sulfoxides 1 and isopropylmagnesium
chloride, with other carbon nucleophiles than the used
Grignard reagent. After some investigation, we found that
the reaction of the magnesium carbenoids 2 with lithium
a-sulfonyl carbanions gave olefins 5 with carbon–carbon
coupling in good to high yields.11 The results are
summarized in Table 3.
The reactions are simply conducted as follows. A
representative example is described using 1a and benzyl
phenyl sulfone (Table 3, entry 1). To a flame-dried flask
were added dry THF followed by i-PrMgCl (2.8 equiv.) at
265 8C and the solution was stirred for 10 min. A solution
of 1a in a minimum amount of THF was added dropwise to
the solution of the Grignard reagent. In another flask, benzyl
phenyl sulfone (3 equiv.) was treated with n-BuLi
(3.6 equiv.) at 0 8C and the solution of the generated lithium
a-sulfonyl carbanion was cooled to 265 8C and transferred
to the solution of the magnesium carbenoid via a cannula.
The whole mixture was stirred and slowly allowed to warm
to 240 8C for about 3.5 h. After quenching the reaction with
water and usual work-up, 93% of 4-(4-methoxyphenyl)-1-
phenyl-1-butene (Table 3, entry 1) was obtained as a
In order to synthesize tert-butylated compound 9g, we tried
the reaction of the magnesium carbenoid 7 with tert-
butyllithium (Scheme 3). The magnesium carbenoid 7 was
generated with 2.5 equiv. of i-PrMgCl in THF at 280 8C for
10 min. To this solution was added excess of tert-
butyllithium and the temperature of the reaction mixture
was allowed to warm to 230 8C for 110 min. Fortunately,
this trial successfully gave the desired 9g in 55% yield.
In conclusion, these reactions mentioned above offer an
interesting method for carbon–carbon coupling, especially,
with a secondary alkyl Grignard reagent.
Scheme 3.

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T. Satoh et al. / Tetrahedron 60 (2004) 5453–5460
Table 3. Treatment of 1-chloroalkyl phenyl sulfoxides 1 with isopropylmagnesium chloride followed by lithium a-sulfonyl carbanions to afford olefins 5
Entry
1, R
PhSO2C(Li)R1R2
R1
5
Yield (%)
E/Z
R2
1
2
3
Ph
Ph
H
5a
5a
5b
93
78a
89
1/2
1/2
1/4
1a
H
H
4
5
6
7
8
9
Ph
Ph
CH3
CH3
Ph
H
H
H
CH3
5c
5d
5e
5f
5g
5h
92
50
78
85
86
88
1/2
—
2/3b
2/3b
2/3b
—
CH3(CH2)3
CH3(CH2)8
CH3
10
11
12
13
Ph
Ph
H
5i
71c
77c
65c
29d
1/2
1b
CH3
H
5j
5k
5l
2/3
2/3b
0/1e
PhCH2C(CH3)2
1c
Ph
H
a
The reaction temperature; 265 8C to room temperature.
The stereochemistry of these products has not been determined yet.
The reaction temperature; 270 to 240 8C.
The reaction conditions; 270 to 0 8C for 150 min.
Only Z-olefin was obtained.
b
c
d
e
mixture of two geometrical isomers. When this reaction was
allowed to warm to room temperature, marked diminishing
of the yields was observed (entry 2).
found to be somewhat lower (65–77%). The sulfoxide 1c
has a quaternary carbon at the 2-position and the olefination
gave markedly diminished yield. Steric hindrance is thought
to be the reason for this result.
1,2-Disubstituted olefins were obtained in good yields by
using the sulfones having both aryl- and alkyl groups at the
carbon bearing the sulfonyl group (entries 1, 3, and 6–8).
Even tri-substituted olefins were obtained in good yields
(entries 4 and 9) except 1,1-diphenyl olefin (50% yield,
entry 5).
It is interesting to note that when 1d was treated with
i-PrMgCl followed by lithium a-sulfonyl carbanions as
above, only dimethylstylene 13 was obtained in almost
quantitative yield (Scheme 4). This result indicated that in
the reaction of the carbenoid 12, rearrangement2,12 is faster
than the reaction with the lithium a-sulfonyl carbanions.
This olefin synthesis was investigated with other 1-chloro-
alkyl phenyl sulfoxides (entries 10–13). The sulfoxide 1b
has a branched chain at the 2-position. The olefination was
carried out in a similar manner as described above and the
desired olefins were obtained; however, the yields were
In conclusion, we were able to generate magnesium
carbenoids from 1-chloroalkyl phenyl sulfoxides with
some Grignard reagents at lower than 260 8C, and found
that the magnesium carbenoid is quite stable at below
Scheme 4.

T. Satoh et al. / Tetrahedron 60 (2004) 5453–5460
5457
260 8C. A new method for carbon–carbon coupling and for
olefin synthesis was realized by using the generated
magnesium carbenoids. Though the selectivity is low, this
reaction offers a unique and interesting method for the
preparation of di- and tri-substituted olefins.
N-Chlorosuccinimide (NCS; 716 mg; 5.36 mmol) was
added to a solution of the sulfoxide (1.36 g; 5 mmol) in
25 ml of carbon tetrachloride and the suspension was stirred
at room temperature for 15 h. The precipitate (succinimide)
was filtered off and the solvent was evaporated. The residue
was purified by silica gel column chromatography to afford
1.49 g (97%) of 1-chloro-3-(4-methoxyphenyl)propyl phenyl
sulfoxide 1a (about 95:5 diastereomeric mixture). The
product was recrystallized to give single diasteromer 1a as
colorless crystals. Mp 101–102.5 8C (AcOEt–hexane); IR
(KBr) 2942, 1609, 1512, 1246, 1088, 1052 (SO), 1034, 817,
749, 685 cm21; 1H NMR d 1.87 (1H, m), 2.51 (1H, m), 2.73
(1H, dt, J¼14.2, 7.8 Hz), 2.88–2.95 (1H, m), 3.79 (3H, s),
4.46 (1H, dd, J¼10.2, 3.6 Hz), 6.83 (2H, d, J¼8.6 Hz), 7.08
(2H, d, J¼8.6 Hz), 7.49–7.57 (3H, m), 7.59–7.65 (2H, m).
MS m/z (%) 308 (Mþ, trace), 182 (28), 121 (100). Calcd for
C16H17ClO2S: M, 308.0638. Found: m/z 308.0637. Anal
calcd: C, 62.23; H, 5.55; Cl, 11.48; S, 10.38. Found: C,
62.02; H, 5.38; Cl, 11.52, S, 10.48.
2. Experimental
2.1. General
Melting points were measured with a Yanagimoto micro
melting point apparatus and are uncorrected. 1H NMR
spectra were measured in a CDCl3 solution with JEOL
JNM-LA 300, 400 and 500 spectrometer. Electron-impact
mass spectra (MS) were obtained at 70 eV by direct
insertion. Silica gel 60 (MERCK) containing 0.5% fluor-
escence reagent 254 and a quartz column were used for
column chromatography and the products having UV
absorption were detected by UV irradiation. In experiments
requiring a dry solvent, THF was distilled from benzo-
phenone ketyl; diisopropylamine and DMF were distilled
over CaH2 and distilled.
2.1.2. 1-Deuterio-1-chloro-3-(4-methoxyphenyl)propane
(8b). A solution of i-PrMgCl (0.6 mmol) in THF was added
to 2 ml of dry THF in a flame-dried flask at 280 8C under
Ar atmosphere. After 10 min, a solution of 1a (62 mg;
0.2 mmol) in THF (0.4 ml) was added dropwise to the
solution at 280 8C. The reaction mixture was stirred for
10 min, then quenched by CD3OD. The whole was extracted
with CHCl3 and the solution was dried over MgSO4. The
product was purified by silica gel column chromatography
to afford 8b (34 mg; 91%) as a colorless oil; IR (neat) 2935,
2.1.1. 1-Chloro-3-(4-methoxyphenyl)propyl phenyl sulf-
oxide (1a). A solution of 3-(4-methoxyphenyl)-1-propanol
6 (1 g; 6 mmol) and diphenyl disulfide (1.71 g; 7.8 mmol) in
20 ml of THF was cooled in an ice bath. To this solution was
added with stirring 2.1 ml (8.4 mmol) of tributylphosphine.
The reaction mixture was stirred at 0 8C for 5 min and at
room temperature for 18 h. The reaction mixture was diluted
with benzene and the solution was washed twice with 5%
NaOH (50 ml) followed by sat. aq. NH4Cl. The solution was
dried over MgSO4 and the solvent was evaporated. The
residue was purified by silica gel column chromatography to
afford 1.53 g (98%) of 3-(4-methoxyphenyl)propyl phenyl
sulfide as colorless crystals. Mp 43–44 8C (hexane); IR
(KBr) 2946, 1610, 1511, 1257, 1243, 1036, 818, 738,
1
1612, 1512, 1246, 1178, 1037, 832 cm21; H NMR d 2.04
(2H, q, J¼7.0 Hz), 2.72 (2H, t, J¼7.0 Hz), 3.50 (1H, t,
J¼7.0 Hz), 3.79 (3H, s), 6.84 (2H, d, J¼8.6 Hz), 7.11 (2H,
d, J¼8.6 Hz). MS m/z (%) 185 (Mþ, 17), 122 (10), 121
(100). Calcd for C10H12DClO: M, 185.0717. Found: m/z
185.0723. When this reaction was quenched by sat. aq.
NH4Cl, 8a was obtained as a colorless oil; IR (neat) 2934,
1613, 1513, 1301, 1245, 1178, 1037, 831 cm21; 1H NMR d
2.05 (2H, quintet, J¼6.6 Hz), 2.72 (2H, t, J¼6.6 Hz), 3.52
(2H, t, J¼6.6 Hz), 3.79 (3H, s), 6.84 (2H, d, J¼8.6 Hz), 7.11
(2H, d, J¼8.6 Hz).
1
690 cm21; H NMR d 1.93 (2H, quintet, J¼7.4 Hz), 2.69
(2H, t, J¼7.4 Hz), 2.90 (2H, t, J¼7.4 Hz), 3.78 (3H, s), 6.82
(2H, d, J¼8.6 Hz), 7.08 (2H, d, J¼8.6 Hz), 7.14–7.18 (1H,
m), 7.25–7.31 (4H, m).
2.1.3. 1-(4-Methoxyphenyl)pentane (9a). A solution of
EtMgCl (1 mmol) in THF was added to 1.8 ml of dry THF
in a flame-dried flask at 280 8C under Ar atmosphere. After
10 min, a solution of 1a (62 mg; 0.2 mmol) in THF (0.4 ml)
was added dropwise to the solution at 280 8C. The reaction
mixture was stirred and slowly allowed to warm to 230 8C
for 110 min, then the reaction was quenched with sat. aq.
NH4Cl. The whole was extracted with CHCl3 and the
solution was dried over MgSO4. The product was purified
by silica gel column chromatography to afford 43 mg (80%)
of 9a as a colorless oil; IR (neat) 2956, 2928, 2856, 1613,
1512, 1465, 1300, 1245, 1176, 1039, 829 cm21; 1H NMR d
0.89 (3H, t, J¼7.0 Hz), 1.29–1.34 (4H, m), 1.58 (2H,
quintet, J¼7.7 Hz), 2.54 (2H, t, J¼7.7 Hz), 3.78 (3H, s),
6.82 (2H, d, J¼8.6 Hz), 7.09 (2H, d, J¼8.6 Hz). MS m/z (%)
178 (Mþ, 19), 121 (100). Calcd for C12H18O: M, 178.1359.
Found: m/z 178.1356.
A solution of the sulfide (1.37 g; 5.34 mmol) in 25 ml of
CH2Cl2 was cooled to 240 8C. To this solution was added
m-chloroperbenzoic acid (70%; 1.37 g; 5.61 mmol) and the
reaction mixture was stirred for 1 h. The reaction was
quenched with sat. aq. Na2SO3 and was diluted with
CH2Cl2. This solution was washed twice with 5% NaOH
(50 ml) followed by sat. aq. NH4Cl. The organic layer was
dried over MgSO4 and the solvent was evaporated. The
product was purified by silica gel column chromatography
to afford 1.41 g (96%) of 3-(4-methoxyphenyl)propyl
phenyl sulfoxide as colorless crystals. Mp 51.5–52.5 8C
(AcOEt–hexane); IR (KBr) 2937, 1613, 1515, 1440, 1260,
1
1044 (SO), 1031, 1007, 818, 742, 688 cm21; H NMR d
1.91 (1H, m), 2.06 (1H, m), 2.68 (2H, m), 2.77 (2H, t,
J¼7.8 Hz), 3.78 (3H, s), 6.81 (2H, d, J¼8.6 Hz), 7.04 (2H,
d, J¼8.6), 7.48 27.52 (3H, m), 7.58–7.60 (2H, m). MS m/z
(%) 274 (Mþ, 0.9), 258 (3), 148 (100), 121 (43), 91(8),
77(14). Calcd for C16H18O2S: M, 274.1025. Found: m/z
274.1015.
2.1.4. 1-(4-Methoxyphenyl)nonane (9b). Colorless oil; IR
(neat) 2926, 2854, 1613, 1512, 1465, 1246, 1040 cm21; 1H
NMR d 0.88 (3H, t, J¼7.0 Hz), 1.26–1.30 (12H, m),

5458
T. Satoh et al. / Tetrahedron 60 (2004) 5453–5460
1.53–1.60 (2H, m), 2.54 (2H, t, J¼7.8 Hz), 3.78 (3H, s),
6.82 (2H, d, J¼8.6 Hz), 7.09 (2H, d, J¼8.6 Hz). MS m/z (%)
234 (Mþ, 25), 122 (10), 121 (100). Calcd for C16H26O: M,
234.1982. Found: m/z 234.1985.
(4.26 mmol) of tributylphosphine. The reaction mixture was
stirred at 0 8C for 5 min and at room temperature for 25 h.
The reaction mixture was diluted with benzene and the
solution was washed twice with 5% NaOH followed by sat.
aq. NH4Cl. The solution was dried over MgSO4 and the
solvent was evaporated. The residue was purified by silica
gel column chromatography to afford 417 mg (54%) of 2,2-
dimethyl-3-phenylpropyl phenyl sulfide as a colorless oil;
IR (neat) 2959, 2925, 1583, 1480, 1467, 737, 702,
2.1.5. 1-(4-Methoxyphenyl)-4-methylpentane (9c). Color-
less oil; IR (neat) 2953, 2931, 2868, 1613, 1512, 1465, 1246,
1176, 1039, 827 cm21; 1H NMR d 0.87 (6H, d, J¼6.4 Hz),
1.18–1.23 (2H, m), 1.54–1.59 (3H, m), 2.52 (2H, t,
J¼7.7 Hz), 3.79 (3H, s), 6.82 (2H, d, J¼8.6 Hz), 7.09
(2H, d, J¼8.6 Hz). MS m/z (%) 192 (Mþ, 21), 121 (100).
Calcd for C13H20O: M, 192.1517. Found: m/z 192.1513.
690 cm21 1H NMR d 1.02 (6H, s), 2.68 (2H, s), 2.87
;
(2H, s), 7.13–7.27 (8H, m), 7.34 (2H, d, J¼8.0 Hz). MS m/z
(%) 256 (Mþ, 72), 165 (100), 123 (33), 91 (92). Calcd for
C17H20S: M, 256.1284. Found: m/z 256.1274.
2.1.6. 1-(4-Methoxyphenyl)-4-methylnonane (9d). Color-
less oil; IR (neat) 2927, 2856, 1614, 1513, 1463, 1246,
1040 cm21; 1H NMR d 0.84 (3H, d, J¼6.8 Hz), 0.88 (3H, t,
J¼7.0 Hz), 1.05–1.41 (11H, m), 1.49–1.65 (2H, m), 2.47–
2.57 (2H, m), 3.79 (3H, s), 6.82 (2H, d, J¼8.6 Hz), 7.09
(2H, d, J¼8.6 Hz). MS m/z (%) 248 (Mþ, 25), 121 (100).
Calcd for C17H28O: M, 248.2139. Found: m/z 248.2147.
A solution of the sulfide (400 mg; 1.56 mmol) in 8 ml of
CH2Cl2 was cooled to 0 8C. To this solution was added
m-chloroperbenzoic acid (70%; 403 mg; 1.64 mmol) and
the reaction mixture was stirred for 20 min. The reaction
was quenched with sat. aq. Na2SO3 and was diluted with
CH2Cl2. This solution was washed twice with 5% NaOH
followed by sat. aq. NH4Cl. The organic layer was dried
over MgSO4 and the solvent was evaporated. The product
was purified by silica gel column chromatography to afford
374 mg (88%) of 2,2-dimethyl-3-phenylpropyl phenyl
sulfoxide as a colorless oil; IR (neat) 2961, 1443, 1083,
2.1.7. [3-(4-Methoxyphenyl)propyl]cyclopentane (9e).
Colorless oil; IR (neat) 2946, 2857, 1613, 1512, 1245,
1039 cm21; 1H NMR d 1.04–1.09 (2H, m), 1.30–1.35 (2H,
m), 1.47–1.62 (6H, m), 1.72–1.81 (3H, m), 2.54 (2H, t,
J¼7.6 Hz), 3.79 (3H, s), 6.82 (2H, d, J¼8.6 Hz), 7.09 (2H,
d, J¼8.6 Hz). MS m/z (%) 218 (Mþ, 24), 122 (11), 121
(100). Calcd for C15H22O: M, 218.1670. Found: m/z
218.1679.
1
1042 (SO), 751, 706 cm21; H NMR d 1.21 (3H, s), 1.22
(3H, s), 2.51 (1H, d, J¼13.5 Hz), 2.79 (1H, d, J¼13.1 Hz),
2.84 (1H, d, J¼13.1 Hz), 2.85 (1H, d, J¼13.5 Hz), 7.19–
7.30 (5H, m), 7.46 27.53 (3H, m), 7.58–7.63 (2H, m). MS
m/z (%) 272 (Mþ, 2), 146 (32), 126 (20), 105 (20), 91 (100).
Calcd for C17H20OS: M, 272.1235. Found: m/z 272.1239.
2.1.8. [3-(4-Methoxyphenyl)propyl]cyclohexane (9f).
Colorless oil; IR (neat) 2922, 2850, 1613, 1512, 1447,
1
1246, 1176, 1039, 828 cm21; H NMR d 0.82–0.89 (2H,
N-Chlorosuccinimide (NCS; 185 mg; 1.39 mmol) was
added to a solution of the sulfoxide (360 mg; 1.32 mmol)
in 2 ml of carbon tetrachloride and the suspension was
stirred at room temperature for 15 h. The precipitate was
filtered off and the solvent was evaporated. The residue was
purified by silica gel column chromatography to afford
397 mg (98%) of 1c as colorless crystals. Mp 79.5–80 8C
(AcOEt–hexane); IR (KBr) 2973, 1494, 1468, 1444, 1090,
m), 1.11–1.24 (6H, m), 1.56–1.70 (7H, m), 2.51 (2H, t,
J¼7.8 Hz), 3.78 (3H, s), 6.82 (2H, d, J¼8.6 Hz), 7.09 (2H,
d, J¼8.6 Hz). MS m/z (%) 232 (Mþ, 31), 121 (100). Calcd
for C16H24O: M, 232.1826. Found: m/z 232.1826.
2.1.9. 1-(4-Methoxyphenyl)-4,4-dimethylpentane (9g). A
solution of i-PrMgCl (0.5 mmol) in THF was added to 2 ml
of dry THF in a flame-dried flask at 280 8C under Ar
atmosphere. After 10 min, a solution of 1a (62 mg;
0.2 mmol) in THF (0.4 ml) was added dropwise to the
solution at 280 8C to give the magnesium carbenoid 7. To
the solution of the carbenoid 7 was added t-BuLi (1.6 mmol)
dropwise with stirring. The reaction mixture was stirred and
slowly allowed to warm to 230 8C for about 110 min, then
the reaction was quenched with sat. aq. NH4Cl. The whole
was extracted with CHCl3 and the solution was dried over
MgSO4. The product was purified by silica gel column
chromatography to afford 9g (23 mg; 55%) as a colorless
oil; IR (neat) 2953, 1613, 1513, 1466, 1247, 1176,
1
1057 (SO), 747, 703 cm21; H NMR d 1.31 (3H, s), 1.32
(3H, s), 2.81 (1H, d, J¼13.5 Hz), 3.01 (1H, d, J¼13.5 Hz),
4.10 (1H, s), 7.21–7.32 (5H, m), 7.51 (5H, s). MS m/z (%)
306 (Mþ, trace), 145 (20), 126 (39), 91 (100). Calcd for
C17H19ClOS: M, 306.0845. Found: m/z 306.0847. Anal
calcd: C, 66.54; H, 6.24; Cl, 11.55; S, 10.45. Found: C,
66.63; H, 6.06; Cl, 11.51; S, 10.40.
2.1.11. 1-Chloro-2-methyl-2-phenylpropyl phenyl sulf-
oxide (1d). To a solution of dry DMF (5 ml) under Ar
atmosphere was added potassium hydroxide (375 mg;
5.75 mmol) and benzenethiol (634 mg; 5.75 mmol). The
reaction mixture was stirred for 15 min and was added
1-chloro-2-methyl-2-phenylpropane (843 mg; 5 mmol).
The reaction mixture was refluxed for 20 h. The whole
mixture was diluted with ether-benzene and the solution was
washed twice with 5% NaOH followed by sat. aq. NH4Cl.
The solution was dried over MgSO4 and the solvent was
evaporated. The residue was purified by silica gel column
chromatography to afford 1.11 g (92%) of 2-methyl-2-
phenylpropyl phenyl sulfide as a colorless oil; IR (neat)
1
1040 cm21; H NMR d 0.86 (9H, s), 1.20–1.23 (2H, m),
1.51–1.58 (2H, m), 2.51 (2H, t, J¼7.8 Hz), 3.79 (3H, s),
6.83 (2H, d, J¼8.6 Hz), 7.10 (2H, d, J¼8.6 Hz). MS m/z (%)
206 (Mþ, 18), 121 (100). Calcd for C14H22O: M, 206.1668.
Found: m/z 206.1666.
2.1.10. 1-Chloro-2,2-dimethyl-3-phenylpropyl phenyl
sulfoxide (1c). A solution of 2,2-dimethyl-3-phenyl-1-
propanol (500 mg; 3.04 mmol) and diphenyl dilsulfide
(862 mg; 3.95 mmol) in 10 ml of THF was cooled in an
ice bath. To this solution was added with stirring 1.06 ml
2966, 1582, 1496, 1480, 1438, 1089, 1025, 738, 697 cm21
1H NMR d 1.47 (6H, s), 3.26 (2H, s), 7.10–7.14 (1H, m),
;

T. Satoh et al. / Tetrahedron 60 (2004) 5453–5460
5459
7.19–7.23 (3H, m), 7.25–7.27 (2H, m), 7.29–7.33 (2H, m),
7.37–7.39 (2H, m). MS m/z (%) 242 (Mþ, 28), 124 (25), 119
(100), 91 (38). Calcd for C16H18S: M, 242.1127. Found: m/z
242.1123.
m/z (%) 238 (Mþ, 5), 122 (9), 121 (100). Calcd for C17H18O:
M, 238.1357. Found: m/z 238.1371.
2.1.13. 4-(4-Methoxyphenyl)-1-(1-naphthyl)-1-butene
(5b). Colorless oil (a mixture of two geometrical isomers;
the ratio is about E/Z¼1:4); IR (neat) 3005, 2932, 1611,
A solution of the sulfide (1.1 g; 4.54 mmol) in 25 ml of
CH2Cl2 was cooled to 0 8C. To this solution was added
m-chloroperbenzoic acid (70%; 1.12 g; 4.77 mmol) and the
reaction mixture was stirred for 20 min. The reaction was
quenched with sat. aq. Na2SO3 and was diluted with
CH2Cl2. This solution was washed twice with 5% NaOH
followed by sat. aq. NH4Cl. The organic layer was dried
over MgSO4 and the solvent was evaporated. The product
was purified by silica gel column chromatography to afford
1.1 g (94%) of 2-methyl-2-phenylpropyl phenyl sulfoxide
as a colorless oil; IR (neat) 3057, 2966, 1497, 1475, 1443,
1
1511, 1246, 1177, 1036, 804, 782 cm21; H NMR d 2.44
(1.6H, m), 2.62 (0.4H, m), 2.65 (1.6H, t, J¼7.6 Hz), 2.81
(0.4H, t, J¼7.6 Hz), 3.75 (2.4H, s), 3.79 (0.6H, s), 5.95
(0.8H, dt, J¼11.6, 7.3 Hz), 6.23 (0.2H, dt, J¼15.6, 7.0 Hz),
6.74–7.24 (6H, m), 7.38–7.52 (3H, m), 7.72–8.02 (3H, m).
MS m/z (%) 288 (Mþ, 18), 167 (18), 165 (12), 121 (100).
Calcd for C21H20O: M, 288.1513. Found: m/z288.1514.
2.1.14. 5-(4-Methoxyphenyl)-2-phenyl-2-pentene (5c).
Colorless oil (a mixture of two geometrical isomers; the
ratio is about E/Z¼1:2); IR (neat) 2932, 2853, 1611, 1512,
1246, 1177, 1037, 820, 761, 701 cm21; 1H NMR d 1.97 (1H,
s), 2.01 (2H, d, J¼1.2 Hz), 2.25 (1.3H, q, J¼7.4 Hz), 2.48
(0.7H, q, J¼7.5 Hz), 2.58 (1.3H, t, J¼7.4 Hz), 2.70 (0.7H, t,
J¼7.4 Hz), 3.77 (2H, s), 3.79 (1H, s), 5.48 (0.65H, dt,
J¼7.3, 1.2 Hz), 5.80 (0.35H, dt, J¼7.4, 1.3 Hz), 6.77–6.85
(2H, m), 7.00–7.03 (1.3H, m), 7.10–7.15 (2H, m), 7.20–
7.36 (3.7H, m). MS m/z (%) 252 (Mþ, 8), 131 (10), 121
(100), 91 (8). Calcd for C18H20O: M, 252.1513. Found: m/z
252.1511.
1
1083, 1041 (SO), 752, 703 cm21; H NMR d 1.56 (3H, s),
1.74 (3H, s), 3.00 (1H, d, J¼13.4 Hz), 3.11 (1H, d,
J¼13.4 Hz), 7.23–7.26 (1H, m), 7.34–7.51 (9H, m). MS
m/z (%) 258 (Mþ, trace), 133 (33), 132 (20), 119 (18), 91
(100). Calcd for C16H18OS: M, 258.1079. Found: m/z
258.1074.
N-Chlorosuccinimide (583 mg; 4.37 mmol) was added to a
solution of the sulfoxide (1.1 g; 4.16 mmol) in 20 ml of
carbon tetrachloride and the suspension was stirred at room
temperature for 20 h. The precipitate was filtered off and the
solvent was evaporated. The residue was purified by silica
gel column chromatography to afford 1.23 g (99%) of 1d as
colorless crystals. Mp 100–101 8C (AcOEt–hexane); IR
(KBr) 3059, 2979, 1496, 1475, 1444, 1088, 1055 (SO), 748,
700 cm21; 1H NMR d 1.58 (3H, s), 1.75 (3H, s), 4.58 (1H,
s), 7.33–7.37 (3H, m), 7.42–7.50 (7H, m). MS m/z (%) 292
(Mþ, trace), 167 (84), 131 (100), 126 (40), 91 (92), 89 (29).
Calcd for C16H17ClOS: M, 292.0689. Found: m/z 292.0684.
Anal calcd: C, 65.63; H, 5.85; Cl, 12.11; S, 10.95. Found: C,
65.66; H, 5.78; Cl, 12.05, S, 10.89.
2.1.15. 4-(4-Methoxyphenyl)-1,1-diphenyl-1-butene (5d).
Colorless crystals. Mp 101–102 8C (hexane); IR (KBr)
2920, 2832, 1609, 1508, 1243, 1227, 1032, 768, 707 cm21
;
1H NMR d 2.39 (2H, q, J¼7.6 Hz), 2.68 (2H, t, J¼7.6 Hz),
3.77 (3H, s), 6.09 (1H, t, J¼7.6 Hz), 6.80 (2H, d, J¼8.6 Hz),
7.04 (2H, d, J¼8.6 Hz), 7.07–7.09 (2H, m), 7.18–7.34 (8H,
m). MS m/z (%) 314 (Mþ, 10), 193 (42), 178 (9) 121 (100),
91 (9). Calcd for C23H22O: M, 314.1669. Found: m/z
314.1665. Anal calcd: C, 87.86; H, 7.05. Found: C, 87.65;
H, 6.99.
2.1.12. 4-(4-Methoxyphenyl)-1-phenyl-1-butene (5a). A
solution of i-PrMgCl (0.56 mmol) in THF was added to
1.8 ml of dry THF in a flame-dried flask at 265 8C under Ar
atmosphere. After 10 min, a solution of 1a (62 mg;
0.2 mmol) in THF (0.3 ml) was added dropwise to the
solution at 265 8C to give the magnesium carbenoid 7.
Benzyl phenyl sulfone (crystals; 139 mg; 0.6 mmol) was
added to a solution of n-BuLi (0.72 mmol) in 5 ml of dry
THF in another flame-dried flask at 0 8C under Ar
atmosphere to give a clear yellow solution, and this solution
was cooled to 265 8C. This solution was added to the
solution of carbenoid 7 via a canula. The reaction mixture
was stirred and slowly allowed to warm to 240 8C for about
3.5 h, then the reaction was quenched with sat. aq. NH4Cl.
The whole was extracted with CHCl3 and the solution was
dried over MgSO4. The product was purified by silica gel
column chromatography to afford 45 mg (93%) of 5a (a
mixture of two geometrical isomers; the ratio is about
E/Z¼1:2) as a colorless oil; IR (neat) 3024, 3007, 2932,
2.1.16. 5-(4-Methoxyphenyl)-2-pentene (5e). Colorless oil
(a mixture of two geometrical isomers; the ratio is about
2:3); IR (neat) 3010, 2933, 1613, 1513, 1300, 1246, 1177,
1
1039, 824 cm21; H NMR d 1.55–1.56 (1.8H, m), 1.63–
1.65 (1.2H, m), 2.23–2.35 (2H, m), 2.58–2.62 (2H, m), 3.78
(3H, s), 5.39–5.49 (2H, m), 6.81–6.83 (2H, m), 7.08–7.12
(2H, m). MS m/z (%) 176 (Mþ, 9), 122 (10), 121 (100).
Calcd for C12H16O: M, 176.1120. Found: m/z 176.1196.
2.1.17. 1-(4-Methoxyphenyl)-3-octene (5f). Colorless oil
(a mixture of two geometrical isomers; the ratio is about
2:3); IR (neat) 3004, 2928, 1612, 1512, 1300, 1246, 1177,
1039, 824 cm21; 1H NMR d 0.86–0.89 (3H, m), 1.23–1.34
(4H, m), 1.97–2.00 (2H, m), 2.24–2.34 (2H, m), 2.58–2.61
(2H, m), 3.78 (3H, s), 5.37–5.43 (2H, m), 6.81–6.83 (2H,
m), 7.08–7.11 (2H, m). MS m/z (%) 218 (Mþ, 6), 122 (9),
121 (100). Calcd for C15H22O: M, 218.1670. Found: m/z
218.1670.
1
2834, 1612, 1512, 1246, 1177, 1037, 826, 699 cm21; H
2.1.18. 1-(4-Methoxyphenyl)-3-tridecene (5g). Colorless
oil (a mixture of two geometrical isomers; the ratio is about
2:3); IR (neat) 3003, 2924, 2853, 1613, 1512, 1464, 1300,
;
1246, 1176, 1040, 823 cm21 1H NMR d 0.88 (3H, t,
NMR d 2.49 (0.7H, q, J¼7.4 Hz), 2.63 (1.3H q, J¼7.3 Hz),
2.69–2.75 (2H, m), 3.78 (2H, s), 3.79 (1H, s), 5.69 (0.65H
dt, J¼11.2, 7.1 Hz), 6.24 (0.35H, dt, J¼15.8, 6.8 Hz), 6.40
(0.35H, d, J¼15.8 Hz), 6.43 (0.65H, d, J¼11.2 Hz), 6.81–
6.85 (2H, m), 7.08–7.14 (2H, m), 7.17–7.33 (5H, m). MS
J¼7.0 Hz), 1.25–1.31 (14H, m), 1.94–1.98 (2H, m), 2.24–
2.36 (2H, m), 2.58–2.61 (2H, m), 3.78 (3H, s), 5.34–5.43

5460
T. Satoh et al. / Tetrahedron 60 (2004) 5453–5460
(2H, m), 6.81–6.83 (2H, m), 7.08–7.11 (2H, m). MS m/z
(%) 288 (Mþ, 5), 122 (9), 121 (100). Calcd for C20H32O: M,
288.2451. Found: m/z 288.2460.
Acknowledgements
We thank Mr Yoshihisa Konishi for his assistance. This
work was supported by a grant from the Ministry of
Education, Culture, Sports, Science and Technology of
Japan to promote a multi-disciplinary research project,
which is gratefully acknowledged.
2.1.19. 5-(4-Methoxyphenyl)-2-methyl-2-pentene (5h).
Colorless oil; IR (neat) 2927, 2855, 1612, 1509, 1300,
1245, 1177, 1039, 827 cm21; 1H NMR d 1.56 (3H, s), 1.68
(3H, s), 2.26 (2H, q, J¼7.6 Hz), 2.57 (2H, t, J¼7.6 Hz), 3.79
(3H, s), 5.16 (1H, m), 6.82 (2H, d, J¼8.6 Hz), 7.10 (2H, d,
J¼8.6 Hz). MS m/z (%) 190 (Mþ, 10), 121 (100), 91 (5).
Calcd for C13H18O: M, 190.1355. Found: m/z 190.1354.
References and notes
2.1.20. 1-Cyclohexyl-2-phenyl-1-ethene (5i). Colorless oil
(a mixture of two geometrical isomers, the ratio is about
E/Z¼1:2); IR (neat) 3025, 3002, 2924, 2850, 1492, 1447,
1. Mathieu, J.; Weill-Raynal, J. Formation of C–C Bonds;
Introduction of a Functional Carbon Atom; Georg Thieme:
Stuttgart, 1973. (b) Mathieu, J.; Weill-Raynal, J. Formation of
C–C Bond; Introduction of a Carbon Chain or an Aromatic
Ring; Georg Thieme: Stuttgart, 1975. (c) Mathieu, J.;
Mathieu, J., J. Formation of C–C Bonds; Introduction of
an a-Functional Carbon Chain; Georg Thieme: Stuttgart,
1979.
1
963, 696 cm21; H NMR d 1.13–1.34 (5H, m), 1.65–1.82
(5H, m), 2.13 (0.35H, m), 2.58 (0.65H, m), 5.48 (0.65H, dd,
J¼11.6, 10.4 Hz), 6.18 (0.35H, dd, J¼15.9, 7.1 Hz), 6.30–
6.36 (1H, m), 7.16–7.35 (5H, m). MS m/z (%) 186 (Mþ, 34),
143 (10), 129 (25), 115 (15), 104 (100), 91 (15). Calcd for
C14H18: M, 186.1408. Found: m/z 186.1414.
2. Kirmse, W. Carbene Chemistry; Academic: New York, 1971.
(b) Stang, P. J. Chem. Rev. 1978, 78, 383.
2.1.21. 1-Cyclohexyl-2-phenyl-1-pentene (5j). Colorless
oil (a mixture of two geometrical isomers, the ratio is about
E/Z¼2:3); IR (neat) 3056, 3022, 2921, 2849, 1599, 1493,
3. Adams, J.; Spero, D. M. Tetrahedron 1991, 47, 1765. (b)
Padwa, A.; Krumpe, K. E. Tetrahedron 1992, 48, 5385. (c)
Padwa, A.; Weingarten, M. D. Chem. Rev. 1996, 96, 223. (d)
Sulikowski, G. A.; Cha, K. L.; Sulikowski, M. M. Tetra-
hedron: Asymmetry 1998, 9, 3145. (e) Dorwald, F. Z. Metal
Carbenes in Organic Synthesis; Wiley-VCH: Weinheim,
1999. (f) Marek, I. Tetrahedron 2002, 58, 9463. (g) Mehta,
G.; Muthusamy, S. Tetrahedron 2002, 58, 9477.
1
1446, 1371, 1026, 894, 757, 699 cm21; H NMR d 1.04–
1.43 (5H, m), 1.58–1.76 (5H, m), 1.99–2.04 (3.6H, m),
2.31–2.38 (0.4H, m), 5.27 (0.6H, d, J¼10.1 Hz), 5.62
(0.4H, d, J¼8.9 Hz), 7.16–7.39 (5H, m). MS m/z (%) 200
(Mþ, 61), 185 (20), 157 (20), 143 (35), 129 (37), 118 (100),
105 (15), 91 (19). Calcd for C15H20: M, 200.1563. Found:
m/z 200.1558.
4. Satoh, T.; Takano, K.; Someya, H.; Matsuda, K. Tetrahedron
Lett. 1995, 36, 7097. (b) Satoh, T.; Takano, K. Tetrahedron
1996, 52, 2349.
2.1.22. 1-Cyclohexyl-4-(4-methoxyphenyl)-1-butene (5k).
Colorless oil (a mixture of two geometrical isomers; the
ratio is about 2:3); IR (neat) 2998, 2922, 2849, 1613, 1513,
5. Satoh, T.; Kurihara, T.; Fujita, K. Tetrahedron 2001, 57, 5369.
(b) Satoh, T.; Saito, S. Tetrahedron Lett. 2004, 45, 347.
6. Satoh, T. J. Syn. Org. Chem. Jpn 1996, 54, 481. (b) Satoh, T.
J. Syn. Org. Chem. Jpn 2003, 61, 98.
1
1447, 1300, 1245, 1177, 1040, 969, 823 cm21; H NMR d
0.96–1.29 (5H, m), 1.48–1.52 (1H, m), 1.61–1.72 (4H, m),
1.86–1.91 (0.4H, m), 2.14–2.21 (0.6H, m), 2.22–2.27
(0.8H, m), 2.31–2.35 (1.2H, m), 2.60 (2H, t, J¼7.6 Hz),
3.78 (3H, s), 5.19–5.42 (2H, m), 6.81–6.84 (2H, m), 7.08–
7.12 (2H, m). MS m/z (%) 244 (Mþ, 8), 122 (10), 121, (100).
Calcd for C17H24O: M, 244.1826. Found: m/z 244.1830.
7. Satoh, T.; Takano, K.; Ota, H.; Someya, H.; Matsuda, K.;
Koyama, M. Tetrahedron 1998, 54, 5557. (b) Satoh, T.;
Sakamoto, T.; Watanabe, M. Tetrahedron Lett. 2002, 43,
2043. (c) Satoh, T.; Sakamoto, T.; Watanabe, M.; Takano, K.
Chem. Pharm. Bull. 2003, 51, 966.
8. A similar study for a generation of magnesium carbenoids has
independently been reported: (a) Hoffmann, R. W.; Nell, P. G.
Angew. Chem. Int. Ed. 1999, 38, 338. (b) Hoffmann, R. W.;
Holzer, B.; Knopff, O.; Harms, K. Angew. Chem. Int. Ed.
2000, 39, 3072.
2.1.23. (Z)-3,3-Dimethyl-1,4-diphenyl-1-butene (5l).
Colorless oil; IR (neat) 3027, 2960, 2926, 1600, 1492,
1
1470, 1452, 721, 699 cm21; H NMR d 0.90 (6H, s), 2.62
(2H, s), 5.50 (1H, d, J¼12.5 Hz), 6.47 (1H, d, J¼12.5 Hz),
6.86 (2H, d, J¼6.5 Hz), 7.14–7.29 (8H, m). MS m/z (%)
236 (Mþ, trace), 145 (100), 130 (7), 117 (11), 91 (21). Calcd
for C18H20: M, 236.1564. Found: m/z 236.1572.
9. Fronza, G.; Fuganti, C.; Serra, S.; Cisero, M.; Koziet, J.
J. Agric. Food Chem. 2002, 50, 2748.
10. The alkylation of a Grignard reagent with magnesium
carbenoids has been known: (a) Hahn, R.; Tompkins, J.
Tetrahedron Lett. 1990, 31, 937. (b) Hoffmann, R. W.; Knopff,
O.; Kusche, A. Angew. Chem. Int. Ed. 2000, 39, 1462. (c)
Holzer, B.; Hoffmann, R. W. Chem. Commun. 2003, 732.
11. The reaction of lithium a-sulfonyl carbanions with magnesium
carbenoids generated from chloro iodoalkanes is known: De
Lima, C.; Julia, M.; Verpeaux, J.-N. Synlett 1992, 133.
12. Satoh, T.; Takano, K. Tetrahedron 1996, 52, 2349.
2.1.24. 2-Methyl-1-phenyl-1-propene (13). Colorless oil;
IR (neat) 3022, 2969, 2929, 1489, 1441, 1376, 740,
698 cm21 1H NMR d 1.86 (3H, s), 1.90 (3H, s), 6.27
;
(1H, s), 7.16–7.32 (5H, m). MS m/z (%) 132 (Mþ, 82) 117
(100), 115 (33), 91 (32). Calcd for C10H12: M, 132.0938.
Found: m/z 132.0938.