410 Bull. Chem. Soc. Jpn., 76, No. 2 (2003)
Kinetically Stabilized Phosphaethene with MeS
2JPC = 2 Hz, o-arom.), and 172.3 (d, 1JPC = 59 Hz, PwC); 31P{1H}
NMR (81 MHz, CDCl3) δ 205.9. Z-8: Colorless plates (MeOH),
then the reaction mixture was stirred for 20 h. The solvent was re-
moved in vacuo and the residue was treated with silica-gel column
chromatography (hexane/toluene 1:1) to afford 203 mg of 11
(83%). 11: Yellow green prisms (hexane), mp 137–140 °C;
1H NMR (200 MHz, CDCl3) δ 1.34 (9H, s, p-t-Bu), 1.59 (18H, s,
o-t-Bu), 2.32 (3H, d, 4JPH = 3 Hz, E-SMe), 2.35 (3H, d, 4JPH = 2
Hz, Z-SMe), 7.51 (2H, d, 4JPH = 3 Hz, arom.); 13C{1H} NMR (50
MHz, CDCl3) δ 18.5 (d, 3JPC = 2 Hz, Z-SMe), 18.8 (d, 3JPC = 13
1
mp 105–106 °C; H NMR (200 MHz, CDCl3) δ 1.35 (9H, s, p-t-
Bu), 1.52 (18H, d, 5JPH = 1 Hz, o-t-Bu), 2.19 (3H, d, 4JPH = 1 Hz,
4
2
SCH3), 7.40 (2H, d, JPH = 1 Hz, arom.), 7.50 (1H, d, JPH = 35
Hz, PwCH); 13C{1H} NMR (50 MHz, CDCl3) δ 19.3 (s, SMe),
31.3 (s, p-CMe3), 32.4 (d, 4JPC = 7 Hz, o-CMe3), 34.9 (s, p-CMe3),
37.9 (s, o-CMe3), 121.7 (d, 3JPC = 1 Hz, m-arom.), 135.8 (d, 1JPC
2
4
= 46 Hz, ipso-arom.), 149.8 (s, p-arom.), 153.4 (d, JPC = 1 Hz,
Hz, E-SMe), 31.1 (s, p-CMe3), 34.6 (d, JPC = 1 Hz, o-CMe3),
o-arom.), 166.9 (d, 1JPC = 53 Hz, PwC); 31P{1H} NMR (81 MHz,
CDCl3) δ 218.8; MS (70 eV, EI) m/z (rel intensity) 336 (M+; 35),
275 (Mes*P+−1; 100). HRMS Found: m/z 336.2044. Calcd for
C20H33PS: m/z 336.2041.
34.9 (s, p-CMe3), 39.8 (d, 3JPC = 1 Hz, o-CMe3), 124.9 (d, 3JPC
=
4
7 Hz, m-arom.), 131.6 (m, ipso-arom.), 151.9 (d, JPC = 2 Hz, p-
arom.), 152.8 (d, 2JPC = 2 Hz, o-arom.), 173.3 (d, 1JPC = 36 Hz,
2
PwC), 197.9 (d, JPC = 10 Hz, COax), 200.2 (m, COeq); 31P{1H}
Preparation of (Z,Z)-2,3-Bis(methylsulfanyl)-1,4-bis(2,4,6-
tri-t-butylphenyl)-1,4-diphosphabuta-1,3-diene (9). To a so-
lution of 7 (150 mg, 0.36 mmol) in THF (5 mL) was added butyl-
lithium (0.38 mmol) at −78 °C and the mixture was stirred for 5
min at −78 °C. Copper(Ⅱ) chloride (0.82 mmol) was added to the
reaction mixture at −78 °C and, after 1 h with stirring, oxygen (5
min, ca. 32 mmol) was bubbled through the mixture at −78 °C.
The reaction mixture was treated with aqueous sodium sulfite and
then warmed to room temperature. The reaction mixture was
treated with ammonia (10% NH3 in sat. NH4Claq) and extracted
with ether. The organic layer was washed with water and dried
with anhydrous magnesium sulfate. The solvent was removed in
vacuo and the residue was purified by silica-gel column chroma-
tography (hexane/toluene 5:1) to afford 54 mg of 9 (45%). 9:Yel-
low prisms (xylene), mp 202–203 °C; 1H NMR (200 MHz,
CDCl3) δ 1.35 (18H, s, p-t-Bu), 1.59 (36H, s, o-t-Bu), 2.11 (6H, s,
SCH3), 7.40 (2H, brs, arom.); 13C{1H} NMR (50 MHz, CDCl3) δ
16.7 (s, SMe), 31.4 (s, p-CMe3), 32.7 (pt, (4JPC + 7JPC)/2 = 4 Hz,
o-CMe3), 35.0 (s, p-CMe3), 37.9 (s, o-CMe3), 121.7 (s, m-arom.),
NMR (81 MHz, CDCl3) δ 215.4 (1JPW = 286 Hz); IR (KBr) ν
2069, 1950, 1934, 1913 cm−1. Anal. Found: C, 44.18; H, 4.99%;
Calcd for C26H35O5PS2W: C, 44.20; H, 4.99%.
Preparation of 1-(2,4,6-Tri-t-butylphenyl)-1-phosphaallene
(13). A solution of 12 (200 mg, 0.52 mmol)17 and potassium t-
butoxide (1.05 mmol) in THF (10 mL) was stirred at 0 °C for 30
min. The reaction mixture was warmed to room temperature and
the solvent was removed in vacuo. The residue was purified by
silica-gel column chromatography (hexane) to afford 130 mg of
13 (83%). Physical data were identical to those in Ref. 34.
Preparation of the Pentacarbonyltungsten(0) Complex of 1-
(2,4,6-Tri-t-butylphenyl)-1-phosphaallene (15). To a solution
of 13 (150 mg, 0.50 mmol) in THF was added W(CO)5(thf) (0.85
mmol) and the mixture was stirred at room temperature for 12 h.
The solvent was removed in vacuo and the residue was purified by
silica-gel column chromatography (hexane) to afford 216 mg of
15 (70%). 15: Yellow powder, mp 98–99 °C; 1H NMR (400 MHz,
CDCl3) δ 1.36 (9H, s, p-t-Bu), 1.71 (18H, s, o-t-Bu), 5.32 (2H, d,
4
3JPH = 51 Hz, PwCwCH2), 7.47 (2H, d, JPH = 4 Hz, arom.);
137.9 (pt, (1JPC
+
4JPC)/2 = 29 Hz, ipso-arom.), 150.1 (s, p-
13C{1H} NMR (100 MHz, CDCl3) δ 31.4 (s, p-CMe3), 34.8 (d,
4JPC = 2 Hz, o-CMe3), 35.6 (s, p-CMe3), 39.4 (s, o-CMe3), 93.9 (d,
2JPC = 13 Hz, PwCwC), 123.5 (d, 3JPC = 8 Hz, m-arom), 125.7 (d,
1JPC = 7 Hz, ipso-arom), 152.6 (d, 4JPC = 2 Hz, p-arom), 155.8 (d,
2JPC = 3 Hz, o-arom), 197.1 (d, 2JPC = 9 Hz, COeq), 199.9 (d, 2JPC
= 34 Hz, COax), 244.6 (d, 1JPC = 85 Hz, PwCwC); 31P{1H} NMR
(81 MHz, CDCl3) δ 42.0 (1JPW = 259 Hz); IR (KBr) ν 2073, 1986,
5
arom.), 154.2 (pt, (2JPC + JPC)/2 = 2 Hz, o-arom.), 177.7 (dd,
1JPC = 13 Hz, JPC = 8 Hz, PwC); 31P{1H} NMR (81 MHz,
2
CDCl3) δ 235.0; UV (hexanes) λmax (log ε) 250 (4.18), 319 (3.96),
396 (3.07) nm; FAB-MS m/z (rel intensity) 670 (M+; 75), 275
(Mes*P+ − 1; 100). Anal. Found: C 71.77; H, 9.83%. Calcd for
C40H64P2S2: C, 71.60; H, 9.62%.
Preparation of 2,2-Bis(methylsulfanyl)-1-(2,4,6-tri-t-butyl-
phenyl)-1-phosphaethene (10) and Reaction with Pentacarbon-
yl(tetrahydrofuran)tungsten(0). To a solution of 7 (46 mg,
0.11 mmol) in THF (5 mL) was added butyllithium (0.14 mmol) at
−78 °C and the mixture was stirred for 10 min. After dimethyl
disulfide (0.13 mmol) was added, the reaction mixture was stirred
for 30 min. The reaction mixture was warmed to room tempera-
ture and the solvent was removed in vacuo. The residue was puri-
fied by silica-gel column chromatography (hexane) to afford 15
1943, 1926 cm−1
.
HRMS Found: m/z 626.1413. Calcd for
C25H31O5PW: m/z 626.1419. Complex 15 was alternatively ob-
tained from 1417 with potassium t-butoxide.
Preparation of (Z)-2-Methylsulfanyl-1-(2,4,6-tri-t-butyl-
phenyl)-1-phosphapropene (Z-16) and the Pentacarbonyltung-
sten(0) Complex (17). To a solution of 12 (200 mg, 0.52 mmol)
in THF (20 mL) was added butyllithium (0.57 mmol) at −78 °C.
After stirring for 10 min, an excess amount of dimethyl disulfide
was added and the mixture was stirred for 1 h. The reaction mix-
ture was warmed to room temperature and the volatile materials
were removed in vacuo. Silica-gel column chromatography (hex-
ane) afforded 165 mg of Z-16 (90%). Z-16: Colorless crystals, mp
1
mg of 10 (35%). 10: Pale yellow solid, mp 93–95 °C; H NMR
(200 MHz, CDCl3) δ 1.35 (9H, s, p-t-Bu), 1.51 (18H, d, 5JPH = 1
Hz, o-t-Bu), 2.22 (3H, d, 4JPH = 1 Hz, Z-SCH3), 2.62 (3H, d, 4JPH
4
1
= 3 Hz, E-SCH3), 7.40 (2H, d, JPH = 1 Hz, arom.); 13C{1H}
97–99 °C; H NMR (400 MHz, CDCl3) δ 1.37 (9H, s, p-t-Bu),
NMR (50 MHz, CDCl3) δ 16.3 (d, 3JPC = 3 Hz, Z-SMe), 19.3 (d,
3JPC = 30 Hz, E-SMe), 31.4 (s, p-CMe3), 32.4 (d, 4JPC = 7 Hz, o-
CMe3), 35.0 (s, p-CMe3), 38.0 (d, 3JPC = 1 Hz, o-CMe3), 121.9 (d,
3JPC = 1 Hz, m-arom.), 135.8 (d, 1JPC = 58 Hz, ipso-arom.), 150.3
(s, p-arom.), 154.1 (d, 2JPC = 2 Hz, o-arom.), 177.0 (d, 1JPC = 74
Hz, PwC); 31P{1H} NMR (81 MHz, CDCl3) δ 206.9; MS (70 eV,
EI) m/z (rel intensity) 382 (M+; 62), 325 (M+ − Bu; 100). To a
solution of 10 (132 mg, 0.35 mmol) in THF (5 mL) was added ca.
0.54 mmol of W(CO)5(thf), prepared from W(CO)6 in THF (23
mL) by irradiation of a medium-pressure Hg lamp (100 W), and
1.54 (18H, s, o-t-Bu), 2.13 (3H, d, 4JPH = 1 Hz, SCH3), 2.38 (3H,
3
d, JPH = 24 Hz, CH3), 7.42 (2H, s, arom.); 13C{1H} NMR (100
MHz, CDCl3) δ 15.7 (d, 3JPC = 2 Hz, SMe), 24.6 (d, 2JPC = 43 Hz,
PwC–CH3), 31.9 (s, p-CMe3), 32.7 (d, 4JPC = 7 Hz, o-CMe3), 35.4
1
(s, p-CMe3), 38.5 (s, o-CMe3), 122.2 (s, m-arom.), 137.0 (d, JPC
= 53 Hz, ipso-arom.), 150.4 (s, p-arom.), 154.1 (s, o-arom.),
178.2 (d, 1JPC = 52 Hz, PwC), 31P{1H} NMR (161 MHz, CDCl3) δ
204. MS (70 eV, EI) m/z (rel intensity) 350 (M+; 37), 293 (M+−t-
Bu; 100). HRMS Found: m/z 350.2200. Calcd for C21H35PS: m/z
350.2197. Compound Z-16 was allowed to react with an excess