The Journal of Organic Chemistry
Article
[D1]methyl (R)-1-(1-naphthyl)ethylthiocarbamate {10b, (R)-
and (S)-[D1]10b}. A solution of mercaptomethylphoshonate24 8 (76
mg, 0.36 mmol) and (R)-(−)-1-(1-naphthyl)ethyl isocyanate (0.62
mL, 0.72 mmol, ee 95%) in dry THF (3 mL) under argon was stirred
for 5 h at rt. Afterward, water (0.25 mL) was added, and the mixture
was stirred for another 2.5 h and concentrated under reduced pressure.
The residue was purified by flash chromatography (hexane/EtOAc,
1:2, Rf 0.61) to yield thiocarbamate 10b (136 mg, 97%) as a colorless
oil. IR (Si): ν 3222, 2980, 2931, 1675, 1533, 1238, 1216, 994 cm−1. 1H
NMR (400.13 MHz, CDCl3): δ 8.04 (d, J = 8.3 Hz, 1H), 7.85−7.75
(m, 1H), 7.74 (d, J = 7.9 Hz, 1H), 7.55−7.35 (m, 4H), 6.59 (br s, 1H,
NH), 5.85 (br s, 1H), 4.61 (dsept, J = 7.7, 6.3 Hz, 2H), 3.18 (AB-syst,
JAB = 15.0 Hz, J = 12.9 Hz, 2H), 1.63 (d, J = 6.8 Hz, 3H), 1.27 (d, J =
6.0 Hz, 3H), 1.26 (d, J = 5.7 Hz, 3H), 1.23 (d, J = 6.2 Hz, 3H), 1.21
(d, J = 6.2 Hz, 3H). 13C NMR (100.61 MHz, CDCl3): δ 164.3 (br s),
137.9, 133.8, 130.7, 128.8, 128.8, 128.3, 126.4, 125.7, 125.2, 123.0,
122.6, 71.40 (d, J = 6.7 Hz), 71.38 (d, J = 6.7 Hz), 60.3, 24.0 (d, J =
153.2 Hz), 23.94 (d, J = 4.5 Hz), 23.91 (d, J = 4.4 Hz), 23.79 (d, J =
4.8 Hz), 23.77 (d, J = 5.2 Hz), 21.1 (br s). 31P NMR (161.98 MHz,
CDCl3): δ 22.5. Anal. Calcd for C20H28NO4PS: C, 58.66; H, 6.89; N,
3.42; S, 7.83. Found: C, 59.05; H, 7.14; N, 3.80; S, 8.41.
not detected, 129.0 (2C, Carom), 128.3 (2C, Carom), 126.6 (Carom), 42.5
(CH2S), 29.0 (J(117/119Sn) = 20.6 Hz, 3C, 3 × CH2(CH2)2Sn), 27.2
(J(117/119Sn) = 55.2 Hz, 3C, 3 × CH2-CH2Sn), 13.7 (3C, 3 ×
CH3(CH2)3), 9.5 (J(117/119Sn) = 334.4 Hz, 3C, 3 × SnCH2(CH2)2),
8.3 (t, J(117/119Sn) = 223.0 Hz, SCH2Sn). Anal. Calcd for C20H36SSn:
C, 56.22; H, 8.49; S, 7.50. Found: C, 56.48; H, 8.45; S, 7.26.
Similarly, mesylates (R)-[D1]3 (1.0 g, 2.49 mmol) and (S)-[D1]3
(1.690 g, 4.22 mmol) were converted to benzylthio-[D1]-
methylstannanes (S)-[D1]12b (870 mg, 82%) and (R)-[D1]12b
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(1.535 g, 85%), respectively. Their H NMR spectra (400.27 MHz,
CDCl3) were identical to that of 12b except for δ 1.77 (s, J(117/119Sn)
= 41.6 Hz, 1H).
(1-Naphthylmethyl)thiomethyl- and (R)-(1-naphthylmethyl)-
thio[D1]methyltributylstannane {12c, (R)-[D1]12c}. 1-Naphthyl-
methanethiol43 (745 mg, 4.66 mmol) was alkylated with mesylate 3
(1.240 g, 3.11 mmol) by the procedure used for the preparation of
allylthiomethylstannane 12a. The combined organic layers were
washed with brine (25 mL) and 2 M NaOH (3 × 25 mL), dried
(MgSO4), and concentrated under reduced pressure. The crude
product was purified by flash chromatography (hexane/CH2Cl2, 30:1,
Rf 0.33) to yield (1-naphthylmethyl)thiomethylstannane 12c (1.219 g,
82%) as a colorless oil. IR (Si): ν 2954, 2922, 2851, 1510, 1462, 1376,
Similarly, (R)-[D1]8 (48 mg, 0.22 mmol) was converted to (R)-
1
1
[D1]10b (66 mg, 73%, ee 23%). The H NMR spectrum (400.27
1074, 1016 cm−1. H NMR (400.27 MHz, CDCl3): δ 8.19−8.11 (d, J
MHz, CDCl3) was identical to that of 10b except for δ 3.22 (d, J =
13.3 Hz, 0.38H), 3.17 (d, J = 13.2 Hz, 0.61H).
= 8.5 Hz, 1H), 7.85−7.68 (m, 2H), 7.55−7.42 (m, 2H), 7.41−7.33 (m,
2H), 4.12 (s, 2H), 1.83 (s, J(117/119Sn) = 40.1 Hz, 2H), 1.49−1.33 (m,
6H), 1.21 (sext, J = 7.3 Hz, 6H), 0.98−0.83 (m, 6H), 0.81 (t, J = 7.3
Hz, 9H). 13C NMR (100.61 MHz, CDCl3): δ 134.1, 133.7, 131.6,
128.6, 127.7, 127.2, 125.8, 125.6, 125.0, 124.3, 40.4, 28.9 (J(117/119Sn)
= 20.9 Hz, 3C), 27.2 (J(117/119Sn) = 55.1 Hz, 3C), 13.6 (3C), 9.5
(J(117/119Sn) = 319.6 Hz, 3C), 9.1 (J(117/119Sn) = 214.4 Hz). Anal.
Calcd for C24H38SSn: C, 60.39; H, 8.02. Found: C, 60.34; H, 7.76.
Similarly, mesylate (S)-[D1]3 (678 mg, 1.69 mmol) was converted
to thiomethylstannane (R)-[D1]12c (642 mg, 79%). The spectro-
Similarly, (S)-[D1]8 (31 mg, 0.14 mmol) was converted to (S)-[D1]
1
10b (50 mg, 86%, ee 51%). The H NMR spectrum (400.27 MHz,
CDCl3) was identical to that of (R)-[D1]10b except for the different
integration of the two doublets δ 3.22 (d, J = 13.3 Hz, 0.74H), 3.17 (d,
J = 13.2 Hz, 0.23H).
(Allylthiomethyl)tributylstannane, (S)- and (R)-(Allylthio[D1]-
methyl)tributylstannane {12a, (S)-and (R)-12a}. Allylmercaptan
(0.20 mL, 2.37 mmol) was added to a solution of t-BuONa (228 mg,
2.37 mmol) in dry THF (5.0 mL) and stirred under argon for 10 min.
The reaction mixture was cooled to −30 °C, and tributylstannylmethyl
mesylate (3) (632 mg, 1.58 mmol) in dry THF (3 mL) was added.
After the mixture was stirred for 15 min, 1 M HCl (8 mL) and hexane
(8 mL) were added. The organic phase was separated and washed with
brine (20 mL), dried (MgSO4), and concentrated under reduced
pressure. The residue was purified by flash chromatography (hexane/
CH2Cl2, 30:1, Rf 0.54) to yield tributylstannylmethyl sulfide (12a)
(500 mg, 84%) as a colorless oil. IR (Si): ν 2956, 2926, 2853, 1635,
1464, 1376, 911 cm−1. 1H NMR (400.27 MHz, CDCl3): δ 5.74 (tdd, J
= 17.2, 10.0, 7.3 Hz, 1H), 5.07 (tdd, J = 10.0, 1.7, 0.8 Hz, 1H), 5.03
(tdd, J = 17.2, 1.7, 1.2 Hz, 1H), 3.06 (ddd, J = 7.3, 1.2, 0.8 Hz, 2H),
1.80 (s, J(117/119Sn) = 41.3 Hz, 2H), 1.60−1.38 (m, 6H), 1.30 (sext, J =
7.3 Hz, 6H), 1.10−0.82 (m, J(117/119Sn) = 50.6 Hz, 6H), 0.87 (t, J =
7.3 Hz, 9H). 13C NMR (100.61 MHz, CDCl3): δ 133.9, 116.7, 41.0,
29.0 (J(117/119Sn) = 20.9 Hz, 3C), 27.3 (J(117/119Sn) = 55.2 Hz, 3C),
13.7 (3C), 9.5 (J(117/119Sn) = 334.7, 319.6 Hz, 3C), 7.5. Anal. Calcd
for C16H34SSn: C, 50.94; H, 9.08. Found: C, 51.16; H, 9.14.
1
scopic data were identical to that of 12c except for the following. H
NMR (400.27 MHz, CDCl3): δ 1.81 (s, J(117/119Sn) = 41.0 Hz, 1H,
CHDSn). 13C NMR (100.61 MHz, CDCl3): δ 8.8 (t, J = 21.0 Hz, 1C,
SCHDSn).
[2,3]-Rerrangement of (Allylthiomethyl)stannanes 12, (R)-
and (S)-[D1]12a, and Derivatization of 3-Butenethiols Formed
from Thiocarbamate 16. Experiment 1. n-BuLi (0.25 mL, 0.39
mmol) was added to the solution of sulfide 12a (131 mg, 0.33 mmol)
in dry THF (2.5 mL) at −95 °C under argon. After 10 min, 2 M
CF3CO2H (70 μL, 0.13 mmol) was added and the mixture was used
immediately for the derivatization as thiol 15 cannot be isolated
because of its low boiling point.25
(R)-(+)-1-Phenylethyl isocyanate (0,10 mL, 0.66 mmol, ee 99%)
was added at −95 °C. The cooling bath was removed and stirring was
continued at rt. After 45 min a saturated aqueous solution of NaHCO3
(10 mL) was added and the mixture was extracted with EtOAc (2 × 20
mL). The combined organic phases were dried (MgSO4) and
concentrated under reduced pressure. The residue was purified by
two flash chromatographies (first: hexane/EtOAc, 10:1, Rf 0.38, side
product derived from isocyanate 0.45; second: hexane/CH2Cl2, 1:1, Rf
0.29, side product derived from isocyanate 0.68) to yield
thiocarbamate 16 (64 mg, 83%) as colorless crystals. Mp: 46−47 °C
Similarly, mesylates4 (R)- and (S)-[D1]3 (690 mg, 1.72 mmol and
635 mg, 1.59 mmol) were converted to sulfides (S)-[D1]12a (537 mg,
1
83%) and (R)-[D1]12a (375 mg, 63%), respectively. The H NMR
spectra (400.27 MHz, CDCl3) were identical to that of 12 except for δ
(hexane). [α]20 = −97.78 (c 0.90, acetone). IR (Si): ν 3293, 2977,
1.78 (br s, J(117/119Sn) = 40.7 Hz, 1H).
D
1652, 1520, 1495, 1217, 699 cm−1. 1H NMR (400.27 MHz, CDCl3): δ
7.37−7.18 (m, 5H, Harom), 5.77 (tdd, J = 17.0, 10.2, 6.7 Hz, 1H, CH
CH2), 5.54 (br s, 1H, NH), 5.06 (qd, J = 17.0, 1.6 Hz, 1H, CH
CH2), 5.05 (br s, 1H, CHCH3), 5.01 (tdd, Jci = 10.2, 1.6, 1.2 Hz, 1H,
CHCH2), 2.95 (AB-sys, JAB = 13.4 Hz, J = 7.1 Hz, 2H, CH2S), 2.35
(tddd, J = 7.1, 6.7, 1.6, 1.2 Hz, 2H, CH2CH2S), 1.49 (d, J = 6.9 Hz, 3H,
CH3CH). 13C NMR (100.61 MHz, CDCl3): δ 142.8, 136.3, 128.7
(2C), 127.5 (2C), 126.0, 116.3, 51.1, 34.5, 29.2, 22.0. Anal. Calcd for
C13H17NOS: C, 66.34; H, 7.28; N, 5.95; S, 13.62. Found: C, 66.16; H,
7.25; N, 6.04; S, 13.40.
Benzylthiomethyl- and (R)- and (S)-Benzylthio[D1]-
methyltributylstannane {12b, (R)- and (S)-[D1]12b}. Benzylmer-
captan (0.35 mL, 3.0 mmol) was alkylated with mesylate 3 (798 mg,
2.0 mmol) by the procedure used for the preparation of
allylthiomethylstannane 12a. The crude product was first heated (45
°C, 0.5 mbar) to remove excess benzylmercaptan and then purified by
flash chromatography (hexane/CH2Cl2, 30:1, Rf 0.33) to yield
benzylthiomethylstannane 12b (786 mg, 92%) as a colorless oil. IR
1
(Si): ν 2955, 2923, 2851, 1493, 1453, 1376, 1071 cm−1. H NMR
(400.27 MHz, CDCl3): δ 7.35−7.15 (m, 5H, Harom), 3.64 (s, 2H,
CH2S), 1.77 (s, J(117/119Sn) = 41.6 Hz, 2H, CH2Sn), 1.57−1.33 (m,
6H, 3 × CH2CH2Sn), 1.30 (sext, J = 7.3 Hz, 6H, 3 × CH2(CH2)2Sn),
0.97−0.80 (m, J(117/119Sn) = 49.6 Hz, 6H, 3 × CH2Sn), 0.85 (t, J = 7.3
Hz, 9H, 3x CH3(CH2)3Sn). 13C NMR (100.61 MHz, CDCl3): δ Cq
1
The H NMR spectra (400.27 MHz, CDCl3) of (R)- and (S)-[D1]
16 were identical to that of 16, except for δ 2.95 (t, J = 7.2 Hz, 1H,
CHD), 2.34 (t, J = 6.9 Hz, CH2CHD). To determine the ee of
derivatives [D1]16 the 1H NMR experiments were performed in
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dx.doi.org/10.1021/jo301441g | J. Org. Chem. 2012, 77, 10021−10034