Bismuth(III)-Promoted Acetylation of Thioethers into Thioacetates
13.6 ppm, 1 sp3 C masked. HRMS (MALDI -ve) calcd. for
= 13.2 Hz, 1 H), 2.39 (s, 6 H), 1.87–1.82 (m, 2 H), 1.40–1.37 (m, 6
C74H21NS [M·–]: m/z = 955.1400, found 955.1406. C74H21NS H), 0.93 (t, J = 6.9 Hz, 3 H) ppm. 13C NMR (125 MHz, CDCl3):
(956.05): calcd. C 92.97, H 2.21, N 1.47; found C 92.99, H 2.37, N
1.51.
δ = 156.6, 155.8, 154.3, 153.5, 153.5, 148.4, 147.4, 146.9, 146.6,
146.4, 146.4, 146.4, 146.3, 146.3, 146.2, 146.1, 146.1, 145.9, 145.7,
145.7, 145.7, 145.7, 145.5, 145.4, 145.4, 145.4, 145.3, 144.8, 144.7,
144.5, 144.5, 143.3, 143.1, 142.8, 142.7, 142.7, 142.7, 142.5, 142.4,
142.3, 142.2, 142.2, 142.2, 142.2, 142.1, 142.0, 141.8, 141.7, 140.3,
140.2, 140.1, 139.7, 138.8, 137.8, 137.3, 137.1, 136.6, 136.1, 135.8,
134.1, 132.3, 131.2, 130.4, 129.7, 126.4, 120.4, 117.8, 81.2, 76.8,
72.6, 68.9, 66.8, 56.6, 46.8, 31.9, 31.1, 30.6, 26.0, 22.8, 16.7, 14.2
ppm. HRMS (MALDI -ve) calcd. for C95H44N4OS [M·–]: m/z =
1288.3241, found 1288.3238. C95H44N4OS (1288.48): calcd. C
88.49, H 3.44, N 4.34; found C 88.35, H 3.36, N 4.46.
Compound 20a: A mixture consisting of C60 (142 mg, 0.197 mmol),
14 (50 mg, 0.26 mmol) and amino acid 18 (190 mg, 0.648 mmol) in
toluene (75 mL) was heated to reflux point for 16 h. The solvent
was removed in vacuo and the residue purified by flash column
chromatography (gradient elution of CS2 to 20% toluene/CS2) to
afford 20a (69 mg, 31%) as a dark brown solid. Rf = 0.33 (20%
1
toluene/CS ). IR: ν = 1596 cm–1. H NMR (500 MHz, CDCl ): δ
˜
2
3
= 7.90 (br. s, 2 H), 7.61 (d, J = 7.8 Hz, 2 H), 7.26 (s, 2 H), 5.17 (s,
1 H), 4.87 (d, J = 9.5 Hz, 1 H), 4.48 (d, J = 13.1 Hz, 1 H), 4.16 (d,
J = 9.5 Hz, 1 H), 3.84 (t, J = 6.6 Hz, 2 H), 3.60 (d, J = 13.1 Hz, 1
H), 2.39 (s, 6 H), 1.87–1.82 (m, 2 H), 1.57–1.51 (m, 2 H), 1.40–1.36
(m, 4 H), 1.21 (s, 9 H), 0.93 (t, J = 7.0 Hz, 3 H) ppm. 13C NMR
(125 MHz, CDCl3): δ = 156.5, 155.8, 154.3, 153.4, 153.3, 147.5,
147.4, 146.8, 146.6, 146.4, 146.4, 146.4, 146.3, 146.3, 146.2, 146.1,
146.1, 145.9, 145.7, 145.7, 145.5, 145.4, 145.4, 145.3, 145.3, 144.8,
144.8, 144.5, 144.5, 143.3, 143.1, 142.8, 142.7, 142.7, 142.7, 142.5,
142.4, 142.3, 142.2, 142.2, 142.2, 142.2, 142.1, 142.1, 141.9, 141.8,
141.7, 140.3, 140.2, 140.0, 139.4, 138.1, 137.8, 137.0, 136.6, 136.1,
135.8, 133.2, 132.5, 131.3, 129.5, 81.0, 76.8, 72.6, 68.8, 66.8, 56.6,
46.2, 31.9, 31.1, 30.6, 26.0, 22.8, 16.7, 14.3 ppm. HRMS (MALDI
Acetylation Reactions (see Table 1)
Entry 1: To a solution of 3a (55 mg, 0.159 mmol) and acetyl chlor-
ide (0.25 mL) in toluene (0.50 mL) and CH3CN (1.0 mL) was
added Bi(OTf)3 (23 mg, 0.035 mmol) and the contents of the vessel
stirred for 30 min at ambient temperature. The reaction mixture
was added to ice water (20 mL) and extracted with small portions
of CH2Cl2 (20 mL in total). The combined organics were passed
through a pad of cotton and the solvent removed under reduced
pressure. The residue was purified by flash column chromatography
(30% CH2Cl2/petroleum spirit) to afford 3b (41 mg, 78%) as a col-
orless oil.
-ve) calcd. for C87H39NOS [M·–]: m/z
= 1145.2758, found
Entry 2: To a solution of 3a (57 mg, 0.164 mmol) and acetyl chlor-
ide (0.25 mL) in toluene (0.50 mL) and CH3CN (1.0 mL) was
added Bi(OTf)3 (11 mg, 0.017 mmol) and the contents of the vessel
stirred for 30 min at ambient temperature. The reaction mixture
was added to ice water (20 mL) and extracted with small portions
of CH2Cl2 (20 mL in total). The combined organics were filtered
through a pad of cotton and the solvent removed under reduced
pressure. The residue was purified by flash column chromatography
(30% CH2Cl2/petroleum spirit) to afford 3b (30 mg, 55%) as a col-
orless oil in addition to 3a (20 mg, 35%).
1145.2839. C87H39NOS (1146.34): calcd. C 91.16, H 3.43, N 1.22;
found C 91.04, H 3.52, N 1.27.
Compound 22: A mixture consisting of C60 (365 mg, 0.506 mmol),
21 (76 mg, 0.58 mmol) and amino acid 18 (718 mg, 2.45 mmol) in
toluene (170 mL) was heated to reflux point for 16 h. The solvent
was removed in vacuo and the residue purified by column
chromatography (gradient elution of CS2 to 20% toluene/CS2) to
afford 22 (150 mg, 27%) as a dark brown solid. Rf = 0.48 (20%
1
toluene/CS ). IR: ν = 3295 cm–1. H NMR (500 MHz, CDCl ): δ
˜
2
3
= 7.88 (br. s, 2 H), 7.59 (d, J = 8.0 Hz, 2 H), 7.22 (s, 2 H), 5.14 (s,
1 H), 4.86 (d, J = 9.6 Hz, 1 H), 4.39 (d, J = 13.1 Hz, 1 H), 4.15 (d,
J = 9.6 Hz, 1 H), 3.83 (t, J = 6.7 Hz, 2 H), 3.57 (d, J = 13.1 Hz, 1
H), 3.10 (s, 1 H), 2.38 (s, 6 H), 1.87–1.81 (m, 2 H), 1.40–1.37 (m,
6 H), 0.93 (t, J = 6.9 Hz, 3 H) ppm. 13C NMR (125 MHz, CDCl3):
δ = 156.5, 155.8, 154.2, 153.3, 153.2, 147.5, 146.8, 146.5, 146.4,
146.4, 146.3, 146.3, 146.3, 146.2, 146.1, 146.1, 146.1, 145.9, 145.7,
145.7, 145.6, 145.5, 145.5, 145.4, 145.4, 145.4, 145.3, 144.8, 144.8,
144.5, 144.5, 143.3, 143.1, 142.8, 142.7, 142.7, 142.7, 142.5, 142.4,
142.3, 142.2, 142.2, 142.2, 142.1, 142.0, 142.0, 141.8, 141.7, 140.3,
140.2, 140.0, 139.7, 138.3, 137.1, 136.6, 136.1, 135.8, 132.7, 132.2,
131.2, 129.6, 122.3, 83.6, 81.1, 78.0, 76.7, 72.6, 68.8, 66.8, 56.6,
31.9, 30.6, 26.0, 22.8, 16.7, 14.3 ppm. HRMS (MALDI -ve) calcd.
for C85H31NO [M·–]: m/z = 1081.2411, found 1081.2381. C85H31NO
(1081.19): calcd. C 94.34, H 2.89, N 1.29; found C 94.17, H 3.02,
N 1.25.
Entry 3: To a solution of 3a (58 mg, 0.167 mmol) and acetyl chlor-
ide (0.25 mL) in toluene (0.50 mL) and CH3CN (1.0 mL) was
added Bi(OTf)3 (12 mg, 0.018 mmol) and the contents of the vessel
stirred for 3 h at ambient temperature. The reaction mixture was
added to ice water (20 mL) and extracted with small portions of
CH2Cl2 (20 mL in total). The combined organics were passed
through a pad of cotton and the solvent removed under reduced
pressure. The residue was purified by flash column chromatography
(30% CH2Cl2/petroleum spirit) to afford 3b (32 mg, 58%) as a col-
orless oil in addition to recovered 3a (12 mg, 21%).
Entry 4: To a solution of 3a (98 mg, 0.283 mmol) in CH2Cl2
(3 mL), toluene (1.5 mL), acetyl chloride (0.5 mL) and acetic acid
(2 drops) was added Bi(OTf)3 (21 mg, 0.032 mmol) and the con-
tents of the vessel stirred for 24 h. The reaction mixture was added
to ice water (20 mL) and extracted with small portions of CH2Cl2
(20 mL in total). The combined organics were passed through a
pad of cotton and the solvent removed under reduced pressure.
The residue was purified by flash column chromatography (40%
CH2Cl2/petroleum spirit) to afford 3b (10 mg, 10%) as a colorless
oil and 24a (20 mg, 30%), a pungent smelling colorless oil.
Compound 23a: To a stirring degassed solution of 22 (49 mg,
0.0453 mmol) and 6a (26 mg, 0.125 mmol) in triethylamine
(0.10 mL) and toluene (10 mL) was added CuI (3 mg, 0.016 mmol)
and the resulting solution stirred 24 h at ambient temperature. The
solvent was removed in vacuo and the residue purified by column
chromatography (0.25% ethyl acetate/toluene) to give 23a (42 mg,
72%) as a dark brown solid. Rf = 0.20 (0.25% ethyl acetate/tolu-
S-{4-[(Triisopropylsilyl)ethynyl]phenyl} Ethanethioate (3b): Rf
=
1
0.33 (30% CH Cl /petroleum spirit). IR: ν = 2156, 1715 cm–1. H
˜
2
2
ene). IR: ν = 1593, 1503 (shoulder) cm–1. 1H NMR (500 MHz, NMR (500 MHz, CDCl3): δ = 7.50 (d, J = 8.1 Hz, 2 H), 7.35 (d,
˜
CDCl3): δ = 8.22 (s, 1 H), 8.01 (br. d, includes br. s, J = 7.4 Hz, 4 J = 8.1 Hz, 2 H), 2.42 (s, 3 H), 1.13 (s, 21 H) ppm. 13C NMR
H), 7.76 (d, J = 8.7 Hz, 2 H), 7.70 (d, J = 8.7 Hz, 2 H), 7.26 (s, 2
H), 5.20 (s, 1 H), 4.88 (d, J = 9.5 Hz, 1 H), 4.47 (d, J = 13.2 Hz, 1
H), 4.18 (d, J = 9.5 Hz, 1 H), 3.84 (t, J = 6.6 Hz, 2 H), 3.62 (d, J
(125 MHz, CDCl3): δ = 193.6, 134.3, 132.8, 128.2, 124.9, 106.3,
92.9, 30.4, 18.8, 11.4 ppm. GC–MS: m/z = 332 [M·+], 289, 247,
207.
Eur. J. Org. Chem. 2015, 4675–4688
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4683