The Journal of Organic Chemistry
Article
4-Methoxyphenyl Phenyl Sulfide (5e). CAS 5633-57-8. Colorless
CONCLUSION
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liquid (95 mg, 88%). H NMR (300 MHz, CDCl3) δ: 7.52−7.44 (m,
[Pd(IPr*OMe)(cin)Cl] performs well in carbon−sulfur bond
formation between aryl bromides or chlorides and aliphatic or
aromatic thiols at low catalyst loadings. Moreover, sterically
hindered and deactivated compounds are well-tolerated. The
reaction can be performed without any additive for a wide
range of substrates. The success of the reaction is attributed to
the outstanding activity of the new Pd−NHC catalyst
[Pd(IPr*OMe)(cin)Cl]. Further investigations are currently
ongoing in our laboratory to extend its use to other reactions.
2H), 7.36−7.12 (m, 5H), 7.02−6.89 (m, 2H), 3.87 (s, 3H). 13C NMR
(101 MHz, CDCl3) δ: 159.8, 138.6, 135.4, 128.9, 128.2, 125.8, 124.3,
115.0, 55.4.
1,3-Dimethoxy-2-phenylsulfanylbenzene (5f). CAS 146643-79-0.
Yellow solid (90 mg, 73%). 1H NMR (300 MHz, CDCl3) δ: 7.41 (t, J
= 8.4 Hz, 1H), 7.24−7.14 (m, 2H), 7.12−7.03 (m, 3H), 6.68 (d, J =
8.4 Hz, 2H), 3.84 (s, 6H). 13C NMR (75 MHz, CDCl3) δ: 162.0,
138.2, 131.7, 128.9, 126.6, 125.0, 107.8, 104.7, 56.7.
4-Methoxy-2,6-dimethylphenyl Phenyl Sulfide (5g). CAS 108125-
1
21-9. Beige solid (112 mg, 92%). H NMR (400 MHz, CDCl3) δ:
7.23−7.14 (m, 2H), 7.12−7.02 (m, 1H), 6.97−6.90 (m, 2H), 6.77 (s,
2H), 3.85 (s, 3H), 2.43 (s, 6H). 13C NMR (101 MHz, CDCl3) δ:
160.1, 145.6, 138.8, 128.8, 125.2, 124.4, 121.3, 113.9, 55.2, 22.1.
2-(2,6-Dimethylphenyl)sulfanyl-1,3,5-trimethylbenzene (6a).
EXPERIMENTAL SECTION
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Preparation of [Pd(IPr*OMe)(cin)Cl] (3). In a glovebox, to a 500
mL round-bottom flask equipped with a magnetic stirring bar were
added IPr*OMeHCl (1) (2.16 g, 2.2 mmol) and KOtBu (0.28 g, 2.4
mmol) in THF (160 mL). The reaction mixture was stirred at room
temperature for 4 h, and then [{Pd(cin)(μ-Cl)}2] (2) (0.512 g, 1
mmol) was added. The reaction mixture was then stirred overnight at
room temperature. After this time, outside the glovebox, THF was
evaporated, and the crude product was dissolved in CH2Cl2, filtered on
a pad of silica covered with Celite, and eluted with CH2Cl2. After
evaporation of the solvents, the complex was precipitated in pentane,
and the supernatant was removed. After drying under high vacuum,
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White solid (119 mg, 93%). H NMR (400 MHz, CDCl3) δ: 7.12−
6.97 (m, 3H), 6.86 (s, 2H), 2.27 (s, 3H), 2.25 (s, 6H), 2.21 (s, 6H).
13C NMR (101 MHz, CDCl3) δ: 140.4, 140.3, 136.7, 134.6, 130.8,
129.3, 128.4, 126.8, 21.7, 20.8. Anal. Calcd for C17H20S: C, 79.63; H,
7.89. Found: C, 79.53; H, 7.81.
Bis(2,6-dimethylphenyl) Sulfide (6b). CAS 52805-90-0. White solid
1
(111 mg, 92%). H NMR (300 MHz, CDCl3) δ: 7.17−6.94 (m, 6H),
2.25 (s, 12H). 13C NMR (101 MHz, CDCl3) δ: 140.5, 134.3, 128.5,
126.9, 21.8.
2,6-Dimethoxyphenyl 2,6-Dimethylphenyl Sulfide (6c). White
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the pure complex was obtained as a beige powder (2.25 g, 85%). H
1
solid (122 mg, 89%). H NMR (300 MHz, CDCl3) δ: 7.18 (t, J =
NMR (300 MHz, CD2Cl2) δ: 7.54−7.19 (m, 26H), 7.18−7.07 (m,
12H), 3.90−3.79 (m, 8H), 6.58 (s, 4H), 5.93 (s, 2H), 5.82 (s, 2H),
5.21 (s, 2H), 5.17−5.05 (m, 1H), 4.58 (d, J = 13.1 Hz, 1H), 3.60 (s,
6H), 2.64 (d, J = 6.5 Hz, 1H), 1.27 (d, J = 9.5 Hz, 1H). 13C NMR (101
MHz, CD2Cl2) δ: 183.7, 158.9, 144.3, 144.2, 143.5, 143.3, 143.2,
142.9, 137.9, 131.3, 130.4, 129.1, 128.5, 128.3, 128.1, 127.5, 127.1,
126.5, 126.4, 123.4, 114.7, 114.6, 108.9, 90.9, 55.0, 51.6, 47.0. Anal.
Calcd for C78H65ClN2O2Pd: C, 77.79; H, 5.44; N 2.33. Found: C,
77.75; H, 5.51; N, 2.38.
8.3 Hz, 1H), 7.07−7.00 (m, 3H), 6.53 (d, J = 8.3 Hz, 2H), 3.71 (s,
6H), 2.41 (s, 6H). 13C NMR (75 MHz, CDCl3) δ: 160.4, 142.3, 134.8,
128.9, 128.1, 127.4, 112.5, 108.1, 104.9, 56.4, 22.1. Anal. Calcd for
C16H18O2S: C, 70.04; H, 6.61. Found: C, 70.15; H, 6.53.
1-Methoxy-4-(4-methylphenyl)sulfanylbenzene (6d). CAS 6013-
1
47-4. White solid (104 mg, 90%). H NMR (300 MHz, CDCl3) δ:
7.50−7.34 (m, 2H), 7.21−7.03 (m, 4H), 6.97−6.84 (m, 2H), 3.85 (s,
3H), 2.34 (s, 3H). 13C NMR (101 MHz, CDCl3) δ: 159.5, 136.1,
134.4, 131.1, 129.8, 129.4, 125.6, 114.9, 55.4, 21.0.
General Procedure for the Preparation of Aryl and Alkyl
Thioethers. In a glovebox, to a vial equipped with a stirring bar and
sealed with a screw cap fitted with a septum was added KOtBu (120
mg, 1.0 mmol). Outside the glovebox, under argon, were added the
aryl halide (0.5 mmol), the thiol (0.6 mmol), and finally a solution of 3
in dioxane (0.60 mg, 1 mL, 0.1 mol %). The reaction mixture was
stirred at 110 °C for 12 h. The solution was then cooled, concentrated
under reduced pressure, and quenched with water (2 mL), and the
product was extracted with Et2O (3 × 2 mL). The combined organic
layers were dried over MgSO4, filtered, and concentrated under
reduced pressure. The crude product was finally purified by flash
chromatography on silica gel with ether/pentane (from 0.5/99.5 to 2/
8) as the eluent.
Bis(4-methoxyphenyl) Sulfide (6e). CAS 3393-77-9. White solid
1
(92 mg, 75%). H NMR (400 MHz, CDCl3) δ: 7.31 (d, J = 8.9 Hz,
4H), 6.86 (d, J = 8.9 Hz, 4H), 3.81 (s, 6H). 13C NMR (75 MHz,
CDCl3) δ: 159.0, 132.8, 127.5, 114.8, 55.4.
1,3-Dimethoxy-2-(4-methoxyphenyl)sulfanylbenzene (6f). CAS
1314254-20-0. Yellow liquid (98 mg, 71%). 1H NMR (300 MHz,
CDCl3) δ: 7.35 (t, J = 8.4 Hz, 1H), 7.21−7.07 (m, 2H), 6.82−6.70 (m,
2H), 6.64 (d, J = 8.4 Hz, 2H), 3.85 (s, 6H), 3.77 (s, 3H). 13C NMR
(75 MHz, CDCl3) δ: 161.3, 157.8, 130.7, 129.5, 128.4, 114.2, 109.5,
104.4, 56.3, 55.3.
o-Methoxyphenyl Mesityl Sulfide (6g). CAS 23075-76-5. White
1
solid (106 mg, 82%). H NMR (300 MHz, CDCl3) δ: 7.14−7.02 (m,
3H), 6.88 (dd, J = 8.1, 1.1 Hz, 1H), 6.75 (td, J = 7.6, 1.2 Hz, 1H), 6.35
(dd, J = 7.8, 1.6 Hz, 1H), 3.98 (s, 3H), 2.41 (s, 6H), 2.36 (s, 3H). 13C
NMR (75 MHz, CDCl3) δ: 155.7, 144.6, 139.7, 129.8, 127.0, 126.1,
125.5, 124.8, 121.7, 110.6, 56.3, 22.0, 21.6.
Phenyl p-Tolyl Sulfide (5a). CAS 3699-01-2. Colorless liquid (92
1
mg, 92%). H NMR (300 MHz, CDCl3) δ: 7.46−7.09 (m, 9H), 2.40
(s, 3H). 13C NMR (75 MHz, CDCl3) δ: 137.6, 137.2, 132.3, 131.1,
130.1, 129.8, 129.1, 126.4, 21.2.
2,6-Dimethylphenyl 2-Methoxyphenyl Sulfide (6h). White solid
1
2,4,6-Trimethylphenyl Phenyl Sulfide (5b). CAS 33667-80-0.
(108 mg, 88%). H NMR (400 MHz, CDCl3) δ: 7.30−7.20 (m, 3H),
1
Colorless liquid (108 mg, 95%). H NMR (400 MHz, CDCl3) δ:
7.08 (t, J = 7.7 Hz, 1H), 6.88 (d, J = 8.1 Hz, 1H), 6.74 (t, J = 7.6 Hz,
1H), 6.33 (dt, J = 7.8, 1.9 Hz, 1H), 3.98 (s, 3H), 2.45 (d, J = 1.5 Hz,
6H). 13C NMR (75 MHz, CDCl3) δ: 155.8, 144.8, 129.7, 128.9, 126.7,
125.6, 124.9, 121.7, 110.6, 56.3, 22.1. Anal. Calcd for C15H16OS: C,
73.73; H, 6.60. Found: C, 73.81; H, 6.50.
7.20 (t, J = 7.6 Hz, 2H), 7.12−7.05 (m, 1H), 7.04 (s, J = 6.7 Hz, 2H),
6.95 (d, J = 8.0 Hz, 2H), 2.42 (s, 6H), 2.35 (s, 3H). 13C NMR (101
MHz, CDCl3) δ: 143.7, 139.3, 138.4, 129.3, 128.97, 126.9, 125.5,
124.5, 21.7, 21.2.
1,3-Dimethyl-2-phenylsulfanylbenzene (5c). CAS 54088-93-6.
Colorless liquid (99 mg, 93%). 1H NMR (300 MHz, CDCl3) δ:
7.28−7.17 (m, 5H), 7.13−7.05 (m, 1H), 6.95 (dd, J = 8.4, 1.2 Hz,
2H), 2.45 (s, 6H). 13C NMR (101 MHz, CDCl3) δ: 143.9, 138.0,
130.5, 129.3, 128.9, 128.5, 125.6, 124.6, 21.9.
2,6-Dimethoxyphenyl 2-Methoxyphenyl Sulfide (6i). Yellow solid
(95 mg, 69%). H NMR (300 MHz, CDCl3) δ: 7.41 (t, J = 8.4 Hz,
1
1H), 7.05 (td, J = 7.7, 1.6 Hz, 1H), 6.83 (d, J = 8.0 Hz, 1H), 6.75−6.61
(m, 3H), 6.50 (dd, J = 7.8, 1.5 Hz, 1H), 3.93 (s, 3H), 3.82 (s, 6H). 13C
NMR (101 MHz, CDCl3) δ: 161.9, 155.6, 131.3, 126.3, 125.1, 125.0,
120.8, 109.9, 106.2, 104.3, 56.3, 55.7. Anal. Calcd for C15H16O3S: C,
65.19; H, 5.84. Found: C, 65.38; H, 6.11.
2-Methyl-1-phenylsulfanylnaphthalene (5d). CAS 93322-81-7.
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Yellow liquid (121 mg, 97%). H NMR (300 MHz, CDCl3) δ: 8.60
(d, J = 7.6 Hz, 1H), 7.96−7.84 (m, 2H), 7.59−7.45 (m, 3H), 7.23−
7.13 (m, 2H), 7.13−7.05 (m, 1H), 7.02−6.89 (m, 2H), 2.71 (s, 3H).
13C NMR (101 MHz, CDCl3) δ: 142.9, 138.2, 135.7, 132.9, 131.1,
130.0, 129.0, 128.9, 128.3, 127.3, 126.2, 126.0, 125.5, 124.7, 22.3.
4-Chlorophenyl 4-Methylphenyl Sulfide (6j). CAS 22865-55-0.
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White solid (100 mg, 85%). H NMR (300 MHz, CDCl3) δ: 7.45−
7.11 (m, 93H), 2.40 (s, 3H). 13C NMR (75 MHz, CDCl3) δ: 138.5,
136.4, 132.9, 132.7, 131.2, 131.1, 130.6, 129.6, 21.6.
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dx.doi.org/10.1021/jo401492n | J. Org. Chem. 2013, 78, 9303−9308