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M. Arisawa et al. / Tetrahedron 67 (2011) 2305e2312
(neat/KBr), a FT/IR-6100 spectrometer (ATR), or a FT/IR-6300 spec-
trometer (ATR). Melting points were determined with a Yanagimoto
micro melting point apparatus without correction. High- and low-
resolution mass spectra were measured on a JEOL JMS-DX-303,
a JEOLJMS-700, a JEOL JMS-T100GC, a JEOLGCmate, oraJMS-T100LC.
2.61 (t, J¼6.3 Hz, 2H), 3.09 (t, J¼6.3 Hz, 2H), 7.21 (d, J¼7.5 Hz, 1H), 7.34
(t, J¼7.6 Hz, 1H), 7.48 (td, J¼7.5, 1.3 Hz, 1H), 8.13 (dd, J¼7.8, 0.9 Hz,1H).
13C NMR (125 MHz, CDCl3)
d 11.3, 26.5, 35.4, 64.7, 127.0, 128.4, 128.8,
130.3, 133.4, 142.0, 188.4. IR (ATR) 2917, 2852, 1670, 1598, 1424, 1290,
1217, 813, 744 cmꢁ1. MS (EI) m/z 238 (Mþ, 21%),191 (MþꢁMeS,100%).
HRMS (ESI) calcd for C12H14NaOS2 [MþNa]þ: 261.0384. Found:
261.0376.
4.2. Typical procedures for a-methylthiolation reaction
In a two-necked flask equipped with a reflux condenser were
placed RhH(PPh3)4 (4 mol %, 11.5 mg), 1,2-bis(diphenylphosphino)
4.2.6. 6-(Methylthio)-6,7,8,9-tetrahydro-5H-benzocyclohepten-5-
one. Colorless oil. 1H NMR (500 MHz, CDCl3)
d 1.89e2.02 (m, 3H),
ethane (8 mol %, 8.0 mg), propiophenone 5 (1.25 mmol, 166
methylthio-2-phenylacetophenone 14 (0.25 mmol, 60.6 mg), and
dimethyl disulfide (12 mol %, 2.7 L) in THF (0.25 mL) under an
m
L), 2-
2.13 (s, 3H), 2.21e2.27 (m, 1H), 2.94 (ddd, J¼15.4, 9.1, 3.7 Hz, 1H),
3.05 (ddd, J¼15.6, 7.3, 4.0 Hz, 1H), 3.74 (dd, J¼8.0, 5.0 Hz, 1H), 7.19
(d, J¼7.7 Hz, 1H), 7.29 (t, J¼7.3 Hz, 1H), 7.40 (td, J¼7.4, 1.5 Hz, 1H),
m
argon atmosphere, and the solution was heated at 90 ꢀC for 3 h. The
solvent was removed under reduced pressure, and the residue was
purified by flash column chromatography on silica gel giving 6
(41.1 mg, 91%) and 1,2-diphenyl-1-ethanone 2 (46.0 mg, 94%) with
the recovery of 5 (86.8 mg, 52%) and 1 (3.6 mg, 6%).
7.62 (dd, J¼7.7, 1.2 Hz, 1H). 13C NMR (125 MHz, CDCl3)
d 15.2, 24.1,
29.9, 34.2, 55.4, 126.5, 128.9, 129.6, 131.5, 138.7, 139.9, 203.0. IR
(ATR) 2921, 2861, 1668, 1597, 1446, 1287, 1267, 771, 735 cmꢁ1. MS
(EI) m/z 206 (Mþ, 11%), 158 (MþꢁMeSH, 100%). HRMS (ESI) calcd for
C12H14NaOS [MþNa]þ: 229.0663. Found: 229.0668.
Their structures were determined by comparing the spectral
data with references: 2-(Methylthio)-1-phenyl-1-ethanone,3 2,2-
di(methylthio)-1-phenyl-1-ethanone,7 2-(methylthio)-1-(4-cya-
4.2.7. 6,6-Di(methylthio)-6,7,8,9-tetrahydro-5H-benzocyclohepten-
5-one11. Colorless oil. 1H NMR (500 MHz, CDCl3)
d
1.88 (t, J¼6.1 Hz,
nophenyl)-1-ethanone,3
2,2-di(methylthio)-1-(4-cyanophenyl)-
2H), 1.99 (quint, J¼6.6 Hz, 2H), 2.08 (s, 6H), 2.86 (t, J¼6.9 Hz, 2H),
7.12 (d, J¼7.5 Hz, 1H), 7.28 (td, J¼7.5, 0.9 Hz, 1H), 7.36 (d, J¼6.5 Hz,
1-ethanone,3 2-(methylthio)-1-(4-methoxyphenyl)-1-ethanone,3
2,2-di(methylthio)-1-(4-methoxyphenyl)-1-ethanone,8 2-(methyl-
thio)-2-phenylcyclohexanone (8),4 and 1-(methylthio)-1-phenyl-
2-butanone (12).4
1H), 7.38 (td, J¼7.4, 1.5 Hz, 1H). 13C NMR (125 MHz, CDCl3)
d 11.8,
22.7, 31.1, 31.5, 68.4, 126.5, 127.8, 128.2, 130.9, 136.7, 138.7, 199.0. IR
(ATR) 2916, 2855, 1677, 1244, 958, 759, 674, 633 cmꢁ1. MS (EI) m/z
252 (Mþ, 36%), 205 (MþꢁMeS, 100%). HRMS (ESI) calcd for
C13H16NaOS2 [MþNa]þ: 275.0540. Found: 275.0531.
4.2.1. 2-(Methylthio)-1-phenyl-1-propanone (6)7. Colorless oil. 1H
NMR (300 MHz, CDCl3)
d
1.54 (d, J¼6.9 Hz, 3H), 1.96 (s, 3H), 4.33 (q,
J¼6.8 Hz, 1H), 7.46 (tt, J¼7.5, 1.5 Hz, 2H), 7.56 (tt, J¼7.4, 1.7 Hz, 1H),
4.2.8. 2-Benzyl-2-(methylthio)cyclohexanone11. Colorless oil. 1H
8.01 (d, J¼7.5 Hz, 2H). 13C NMR (75 MHz, CDCl3)
d
10.8, 15.0, 40.7,
NMR (600 MHz, CDCl3)
d
1.51 (qt, J¼13.5, 4.3 Hz, 1H), 1.56e1.59 (m,
128.4, 128.4, 132.9, 135.5, 194.9. IR (neat) 3060, 2973, 2924, 1674,
1447,1334, 1235, 950, 726, 703 cmꢁ1. MS (EI) m/z 180 (Mþ, 26%),134
(MþꢁCH2S, 59%), 105 (MþꢁMeSCHMe, 100%). HRMS (EI) calcd for
C10H12OS: 180.0609. Found: 180.0598.
1H), 1.75 (dq, J¼14.5, 3.2 Hz, 1H), 1.82 (ddd, J¼14.5, 13.1, 4.1 Hz, 1H),
1.91e2.00 (m, 2H), 1.96 (s, 3H), 2.25 (dquint, J¼15.1, 2.1 Hz,1H), 2.94
(d, J¼14.1 Hz, 1H), 3.11 (ddd, J¼15.1, 14.0, 6.2 Hz, 1H), 3.19 (d,
J¼14.0 Hz, 1H), 7.19 (d, J¼7.5 Hz, 2H), 7.21 (tt, J¼7.4, 1.7 Hz, 1H), 7.26
(tt, J¼7.3, 1.5 Hz, 2H). 13C NMR (100 MHz, CDCl3)
d 11.4, 20.6, 26.1,
4.2.2. 2-(Methylthio)-1-indanone9. Colorless oil. 1H NMR (500 MHz,
35.7, 37.0, 39.3, 57.0, 126.4, 127.8, 131.0, 137.0, 206.1. IR (neat) 3028,
2937, 2862, 1699, 1496, 1447, 1417, 1124, 700 cmꢁ1. MS (EI) m/z 234
(Mþ, 46%), 188 (MþꢁCH2S, 32%), 187 (MþꢁMeS, 38%), 143 (MþꢁBn,
100%). HRMS (EI) calcd for C14H18OS: 234.1078. Found: 234.1065.
CDCl3)
d 2.25 (s, 3H), 2.95e3.02 (m, 1H), 3.57e3.64 (m, 2H), 7.40
(t, J¼7.5 Hz, 1H), 7.44 (d, J¼7.7 Hz, 1H), 7.61 (t, J¼7.5 Hz, 1H), 7.80
(d, J¼7.7 Hz, 1H). 13C NMR (125 MHz, CDCl3)
d 13.8, 34.2, 46.8, 124.5,
126.3,127.8,135.1,135.3,152.0, 202.9. IR (ATR) 2918, 2843,1701,1607,
1463, 1431, 1274, 743 cmꢁ1. MS (EI) m/z 178 (Mþ, 36%), 132
(MþꢁCH2S, 100%). HRMS (ESI) calcd for C10H11OS [MþH]þ: 179.0531.
Found: 179.0523.
4.2.9. (2R
*
,6S )-2-Benzyl-6-(methylthio)cyclohexanone. Colorless oil.
*
1H NMR (600 MHz, CDCl3)
d
1.31 (qd, J¼13.0, 3.6 Hz, 1H), 1.64 (dquint,
J¼13.9, 3.5 Hz,1H),1.84 (qt, J¼13.1, 4.0 Hz,1H),1.95e2.00 (m,1H), 2.01 (s,
3H), 2.07e2.17 (m, 2H), 2.42 (dd, J¼14.1, 8.9 Hz, 1H), 3.24 (dd, J¼14.1,
4.8 Hz,1H), 3.29 (dd, J¼4.6, 2.6 Hz,1H), 3.41 (ddd, J¼12.9, 8.8, 5.2 Hz,1H),
7.18 (d, J¼7.6 Hz, 2H), 7.19 (t, J¼7.6 Hz, 1H), 7.27 (t, J¼7.6 Hz, 2H). 13CNMR
4.2.3. 2,2-Di(methylthio)-1-indanone. Colorless solid. Mp 65 ꢀC
(CHCl3). 1H NMR (500 MHz, CDCl3)
d 2.22 (s, 6H), 3.47 (s, 2H), 7.38 (d,
J¼7.5 Hz,1H), 7.42 (t, J¼7.3 Hz,1H), 7.62 (td, J¼7.6, 0.9 Hz,1H), 7.83 (d,
(150 MHz, CDCl3) d 15.2, 21.2, 32.9, 33.1, 35.3, 45.9, 53.9, 126.0, 128.3,
J¼7.7Hz,1H).13C NMR (125MHz, CDCl3)
d
12.6, 43.9, 62.1,125.6,126.0,
129.1, 140.2, 209.5. IR (neat) 3060, 3027, 2933, 2860, 1699, 1496, 1453,
1441, 754, 703 cmꢁ1. MS (EI) m/z 234 (Mþ, 40%), 191 (MþꢁC3H7, 40%),
186 (MþꢁMeSH,100%). HRMS (EI) calcd for C14H18OS: 234.1078. Found:
234.1062. The configuration of the 2-benzyl group was determined by
128.2, 133.7, 135.3, 149.1, 197.1. IR (ATR) 2916, 2852, 1694, 1432, 851,
757, 647cmꢁ1. MS(EI)m/z224(Mþ, 20%),177(MþꢁMeS,100%). HRMS
(ESI) calcd for C11H13OS2 [MþH]þ: 225.0408. Found: 225.0402.
the coupling constant J¼12.9 Hz of the 2-axial proton (
configuration of the 6-methylthio group was determined by the cou-
3.29).
d 3.41). The
4.2.4. 2-(Methylthio)-3,4-dihydro-1(2H)-naphthalenone. Colorless
oil. 1H NMR (500 MHz, CDCl3)
d
2.16 (s, 3H), 2.33 (dq, J¼13.9, 4.2 Hz,
pling constant J¼4.6 Hz of the 6-equatorial proton (
d
1H), 2.53 (ddt, J¼13.8, 11.8, 4.4 Hz, 1H), 2.84 (dt, J¼17.0, 4.2 Hz, 1H),
3.22 (ddd, J¼16.9, 12.0, 4.8 Hz, 1H), 3.50 (t, J¼4.2 Hz, 1H), 7.22 (d,
J¼7.7 Hz, 1H), 7.33 (t, J¼7.6 Hz, 1H), 7.72 (td, J¼7.5, 1.3 Hz, 1H), 8.10
δ 2.1-2.2
O
H
δ 3.29
δ 1.31
δ 3.24
δ 2.42
δ 2.1-2.2
H
H
H
H
H
(dd, J¼7.8, 0.9 Hz, 1H). 13C NMR (125 MHz, CDCl3)
d
14.2, 25.8, 28.6,
H
H
50.0, 126.8, 128.1, 128.5, 130.7, 133.3, 142.7, 192.3. IR (ATR) 2919,
2854, 1674, 1600, 1454, 1301, 1282, 1241, 741 cmꢁ1. MS (EI) m/z 192
(Mþ, 45%), 146 (MþꢁCH2S, 100%). HRMS (ESI) calcd for C11H13OS
[MþH]þ: 193.0687. Found: 193.0687.
δ 1.64
δ 1.84
H
δ
7.19
S
H
δ 2.0
H
H
Me
δ 7.27
H
δ 7.18
δ 3.41
δ
2.01
4 . 2 . 5 . 2 , 2 - D i ( m e t h yl t h i o ) - 3 , 4 - d i h y d r o - 1 ( 2 H ) - n a p h -
4.2.10. 2-Methyl-2-(methylthio)cyclohexanone11. Colorless oil. 1H NMR
(500 MHz, CDCl3)
1.34 (s, 3H), 1.57e1.67 (m, 2H), 1.85 (td, J¼13.4,
thalenone10. Colorless oil. 1H NMR (500 MHz, CDCl3)
d
2.07 (s, 6H),
d