E. Hasegawa et al. / Tetrahedron 64 (2008) 7724–7728
7727
1
8
9a–d,20b) are known compounds. Spectral data of 1b–3b, 5b,d,
þ
7
8
,
172.0, 203.5. LRMS (EI) m/z (relative intensity) 218 (M , 66.4), 145
(100). HRMS (EI) calcd for C13 218.0943, found 218.0943.
b, 9e and 11 are presented below. While 10a was previously
characterized,
MeOH.
14 3
H O
20b
crude 10 were usually treated with NaOAc in
4.2.2.5. Compound 5d. Colorless oil; IR (Neat) 1742, 1716 cm 1; 1H
ꢀ
NMR (200 MHz)
d
1.15 (t, J¼7.1 Hz, 3H), 1.68 (s, 3H), 2.58–3.27 (m,
13
4
4
0
.2. Free radical reactions with TTMSS and TBTH
4H), 4.12 (qd, J¼7.1, 1.4 Hz, 2H), 7.20–7.28 (m, 4H); C NMR
(50 MHz)
d
13.9, 22.2, 28.0, 37.5, 59.2, 61.7, 126.7, 127.3, 127.5, 128.3,
þ
.2.1. Et
Typical procedure is represented by 3a. TTMSS (0.15 mL,
.49 mmol) and Et B (1.0 M in THF, 0.10 mL, 0.10 mmol) were added
prepurged BTF solution (10 mL) of 3a (155.6 mg,
.50 mmol). Then, air was introduced by syringe (2 mL). The
3
B initiated reaction with TTMSS in BTF or benzene
135.8, 137.6, 171.4, 208.5. LRMS (EI) m/z (relative intensity) 232 (M ,
29.2), 159 (100). HRMS (EI) calcd for C14
232.1093.
16 3
H O 232.1099, found
3
to
0
a N
2
4.3. Electron-transfer reaction with TBPA and FeCl
3
resulting solution was stirred at room temperature for 6 h. The
residue obtained by concentration was subjected to column chro-
4.3.1. TBPA promoted reaction in BTF
matography using EtOAc/n-C
6
H
14 (1/5). Then, 4a (27.7 mg,
TBPA (332.7 mg, 0.41 mmol) was added to a solution of 8a
(98.7 mg, 0.40 mmol) in BTF (8 mL) under N . The resulting mixture
was stirred for 30 min. Then, it was filtered and washed with Et
to remove unreacted TBPA. The filtrate was concentrated and
subjected to column chromatography using CH Cl /n-C 14 (1/1) to
give the mixture of 9a and 10a together with tris(p-bromophe-
nyl)amine. Subsequently, this product mixture was refluxed with
NaOAc (2.06 mmol) for 2 h in MeOH (8 mL). Then, extraction with
0
.12 mmol, 24%) and 5a (86.0 mg, 0.37 mmol, 74%) were separated.
2
Reactions of 3a in benzene, other 3 in BTF, and 1a,b were similarly
performed. When column separation could not remove organo-
silicone compounds, further TLC separation was necessary. If these
separations were not satisfactory, H NMR analysis was performed
using an internal standard (triphenyl methane).
2
O
2
2
6
H
1
4
.2.2. AIBN initiated reaction with TTMSS or TBTH in BTF or
benzene
TTMSS (0.15 mL, 0.49 mmol) was added to a N
solution (10 mL) of 3a (155.6 mg, 0.50 mmol) and AIBN (8.3 mg,
.051 mmol). The resulting solution was refluxed for 6 h. The resi-
Et
aqueous NaHCO
MgSO . The residue obtained after concentration was subjected to
TLC (CH Cl /n-C
other solvents and other 8 in BTF were similarly performed. How-
ever, in the case of 8b, TLC separation of the crude reaction mixture
obtained from the reaction with TBPA produced 11.
2
O was performed, and the extract was treated with water, satd
3
, satd aqueous NaCl, and dried over anhydrous
2
prepurged BTF
4
2
2
6
H14¼1/1) and 9a was obtained. Reactions of 8a in
0
due obtained by concentration was subjected to same column
chromatography separation as described above to give 4a (87.7 mg,
0
.38 mmol, 76%) and 5a (26.0 mg, 0.11 mmol, 22%). Reactions of 3a
with TBTH in benzene, other 3 with TTMSS in BTF and with TBTH in
benzene, were similarly performed. In the case of TBTH reactions,
reaction solutions were subjected to DBU workup procedure to
4.3.2. FeCl
A BTF solution (3 mL) of 8a (123.2 mg, 0.50 mmol) was added to
FeCl (178.4 mg, 1.10 mmol) and pyridine (0.040 mL, 0.50 mmol) in
the presence or absence of Bmim PF
2 mL) under N . The resulting mixture was stirred under N
room temperature for 1 h. Then, it was extracted with Et O after
addition of water. The extract was treated with water, satd aqueous
Na , satd aqueous NaHCO , satd aqueous NaCl, and dried over
anhydrous MgSO . The residue obtained after concentration was
subjected to TLC (CH Cl /n-C
14¼1/1) to give 10a. In the absence
, 82.7 mg of 8a (0.34 mmol, 67%) was also recovered.
3
promoted reaction on BTF
3
2
6
þ
ꢀ
6
remove organotin compounds.
(0.23 mL, 1.10 mmol) in BTF
at
(
2
2
4
.2.2.1. Compound 1b. Pale yellow oil; IR (Neat) 1710 cmꢀ1; 1
NMR (270 MHz)
1.72–2.10 (m, 4H), 3.09 (d, J¼18.9 Hz, 1H), 3.37 (d,
J¼18.9 Hz,1H), 3.56 (d, J¼10.0 Hz,1H), 3.65 (d, J¼10.0 Hz,1H), 4.89–
.96 (m, 2H), 5.62–5.77 (m,1H), 7.36–7.50 (m, 2H), 7.63 (m,1H), 7.76
m, 1H); 13C NMR (50 MHz)
28.6, 36.2, 37.4, 38.8, 53.2,115.2,124.2,
26.4, 127.7, 135.4, 136.4, 137.3, 152.7, 206.9. LRMS (EI) m/z (relative
H
2
d
2
S
2
O
3
3
4
(
1
4
d
2
2
6
H
þ
ꢀ
6
of Bmim PF
þ
þ
intensity) 278 (M , 0.4), 280 (M þ2, 0.4), 129 (100).
Then, 10a was subjected to NaOAc treatment described above to
give 9a, 12.7 mg (0.074 mmol, 15%) or 58.5 mg (0.34 mmol, 68%), in
þ
ꢀ
6
, respectively.
4
.2.2.2. Compound 2b (mixture of two diastereomers). Pale yellow
the absence or presence of Bmim PF
ꢀ
1 1
oil; IR (Neat) 1700 cm ; H NMR (270 MHz)
major isomer), 1.10 (d, J¼7.6 Hz, 3H, minor isomer), 1.22–1.46 (m,
H), 1.61–1.70 (m,1H), 1.96–2.08 (m, 2H), 2.24–2.45 (m, 2H), 3.11 (d,
d
1.07 (d, J¼6.5 Hz, 3H,
4.3.2.1. Compound 8b. Pale yellow oil; IR (Neat) 1322, 1250, 1186,
ꢀ1
1
2
1144, 872, 840 cm
; H NMR (270 MHz) d 0.22 (s, 9H), 0.53 (d,
J¼16.2 Hz, 1H), 3.16 (d, J¼16.2 Hz, 1H), 7.33–7.42 (m, 2H), 7.57 (m,
J¼4.9 Hz, 1H), 1.13 (d, J¼4.9 Hz, 1H), 1.44 (s, 3H), 2.84 (d, J¼16.7 Hz,
1
4
H), 7.75 (m, 1H); 13C NMR (50 MHz)
d 20.1, 21.0, 34.8, 35.6, 39.3,
1H), 2.98 (d, J¼16.7 Hz, 1H), 7.11–7.23 (m, 3H), 7.35–7.38 (m, 1H);
13
4.7, 46.1, 56.8, 124.0, 126.2, 127.2, 134.5, 136.1, 152.8, 211.4. LRMS
C NMR (68 MHz)
d
1.4, 17.6, 27.6, 28.6, 41.2, 71.0, 121.9, 125.0,
þ
þ
(
EI) m/z (relative intensity) 200 (M , 11.5), 145 (100). HRMS (EI)
125.8,126.0,138.6,147.3. LRMS (EI) m/z (relative intensity) 232 (M ,
calcd for C14H16O 200.1201, found 200.1204.
0.8), 73 (100).
ꢀ
ꢀ1
4.3.2.2. Compound 9e. Pale yellow oil; IR (Neat) 1638, 1302 cm ;
H NMR (270 MHz) d 1.56–1.67 (m, 2H), 2.04–2.10 (m, 2H), 2.22–
4
.2.2.3. Compound 3b. Colorless oil; IR (Neat) 1736, 1712 cm 1; 1H
1
NMR (200 MHz)
(
4
d
1.23 (t, J¼7.0 Hz, 3H), 3.39 (d, J¼18.0 Hz, 1H), 3.79
d, J¼18.0 Hz, 1H), 3.80 (d, J¼10.4 Hz, 1H), 4.01 (d, J¼10.4 Hz, 1H),
2.28 (m, 2H), 2.52–2.56 (m, 2H), 3.01–3.05 (m, 2H), 4.97–5.05 (m,
2H), 5.71–5.86 (m, 1H), 6.22 (s, 1H), 7.15–7.18 (m, 1H), 7.27–7.42 (m,
13
.19 (qd, J¼7.0, 1.1 Hz, 2H), 7.42–7.67 (m, 3H), 7.79 (m, 1H); C NMR
13
(
50 MHz)
d
14.0, 34.4, 36.7, 61.4, 62.3, 125.0, 126.4, 127.9, 134.8,
2H), 7.77–7.80 (m, 1H); C NMR (68 MHz) d 27.0, 33.2, 33.6, 34.2,
þ
1
2
35.8,153.2,168.5,199.0. LRMS (EI) m/z (relative intensity) 296 (M ,
40.1, 115.1, 126.6, 128.4, 129.1, 129.5, 131.8, 137.7, 139.1, 139.8, 162.1,
þ
þ
.8), 298 (M þ2, 2.8), 218 (100).
193.2. LRMS (EI) m/z (relative intensity) 226 (M , 21.7), 129 (100).
HRMS (EI) calcd for C16
H18O 226.1358, found 226.1359.
ꢀ
4
.2.2.4. Compound 5b. Pale yellow oil; IR (Neat) 1684 cm 1; 1
1.19 (t, J¼7.1 Hz, 3H), 1.52 (s, 3H), 3.00 (d,
J¼17.5 Hz, 1H), 3.71 (d, J¼17.5 Hz, 1H), 4.15 (q, J¼7.1 Hz, 2H), 7.37–
H
4.3.2.3. Compound 11. Orange oil; IR (KBr) 3308 cm 1; 1H NMR
ꢀ
NMR (200 MHz)
d
(200 MHz)
7.67–7.74 (m, 1H); 8.05–8.12 (m, 1H); C NMR (50 MHz)
110.8, 119.7, 121.3, 122.6,124.3, 126.5, 127.0, 134.8, 135.8, 151.0. LRMS
d 2.44 (s, 3H), 6.65 (s, 1H), 7.21 (s, 1H), 7.35–7.49 (m, 2H),
13
13
7
d
.50 (m, 2H), 7.60–7.68 (m, 1H), 7.80 (m, 1H); C NMR (50 MHz)
d 21.8,
14.0, 21.0, 40.0, 56.0, 61.5, 124.9, 126.4, 127.8, 134.7, 135.3, 152.6,