6416 Organometallics, Vol. 26, No. 25, 2007
Ito et al.
MHz, CDCl3) δ 0.90 (t, J ) 6.9 Hz, 3H, Me), 1.21-1.61 (m, 8H,
CH2), 2.39 (t, J ) 6.9 Hz, 2H, CH2), 3.75 (s, 3H, CO2Me), 3.87 (s,
3H, CO2Me), 6.17 (s, 1H, CCH). 13C{1H} NMR (75 MHz, CDCl3)
δ 14.2, 19.9, 22.6, 28.1, 28.7, 31.3, 52.2, 53.1, 75.7, 101.5, 126.2,
131.1, 164.7, 165.0. IR (KBr, cm-1) ν 2219, 1747, 1726. HR-MS:
calcd for C14H21O4 (M+), 253.1434; found, 253.1440. 4i-E: 1H
NMR (300 MHz, CDCl3) δ 2.51 (t, J ) 7.1 Hz, 2H, CH2), 3.81 (s,
3H, CO2Me), 3.85 (s, 3H, CO2Me), 7.04 (s, 1H, CCH) (signals of
the cyclohexyl group cannot be distinguished from those of
byproducts).
with hexane/ethyl acetate (2:1) as an eluent to give 6-ip (52.8 mg,
0.072 mmol, 78%). The preparation procedure of 6-dm was similar
to that of 6-ip. A mixture of 5-dm (28.1 mg, 0.050 mmol) and 3
(36.0 mg, 0.25 mmol) in toluene (2.0 mL) was stirred at 60 °C for
30 h. The mixture was purified by column chromatography on silica
gel with methanol/ethyl acetate to give 6-dm (23.8 mg, 0.034 mmol,
68%). 6-ip: 1H NMR (300 MHz, CDCl3) δ 0.50 (brd, J ) 5.4 Hz,
3H, CHMe2), 0.72 (d, J ) 6.9 Hz, 3H, CHMe2), 0.89 (d, J ) 6.9
Hz, 3H, CHMe2), 1.07 (d, J ) 6.9 Hz, 3H, CHMe2), 1.99 (s,
3H, OAc), 2.28-2.58 (m, 2H), 2.50 (s, 6H, Me), 2.94 (brs,
3H, CO2Me), 3.69 (s, 3H, CO2Me), 3.87 (m, 1H), 4.38-4.50 (m,
1H), 4.56-4.76 (m, 4H), 6.66 (s, 1H), 7.28-7.35 (m, 3H, C6H5),
7.86 (br, 2H). 13C{1H} NMR (75 MHz, CDCl3) δ 14.4, 17.1, 19.05,
19.09, 19.2, 20.6, 23.7, 29.0, 30.4, 50.2 (CO2Me), 52.1 (CO2Me),
67.1, 70.3, 72.2, 86.6, 91.6, 124.3, 126.5, 126.9, 127.2, 127.6,
Dimethyl 2-((Trimethylsilyl)ethynyl)maleate (4j-Z) and the
Corresponding Fumarate (4j-E). 4j-Z: 26% yield (Z:E )
99:1), colorless oil. 1H NMR (300 MHz, CDCl3) δ 0.22 (s, JSiH
)
7.2 Hz, 9H, Me), 3.75 (s, 3H, CO2Me), 3.87 (s, 3H, CO2Me),
6.28 (s, 1H, CCH). 13C{1H} NMR (75 MHz, CDCl3) δ -0.3, 52.3,
53.2, 98.1, 105.5, 128.4, 130.0, 164.3, 164.4. IR (KBr, cm-1) ν
2150, 1748, 1728. HR-MS: calcd for C11H17O4Si (M+), 241.0891;
found, 241.0896. 4j-E: 1H NMR (300 MHz, CDCl3) δ 0.28 (s,
9H, Me), 3.82 (s, 3H, CO2Me), 3.86 (s, 3H, CO2Me), 7.09 (s, 1H,
CCH).
131.8, 139.8, 140.2, 161.0, 171.5 (Rh-CdC), 171.7 (d, JRhC
)
4.6 Hz), 172.0 (d, JRhC ) 5.1 Hz), 175.5 (d, JRhC ) 33 Hz,
Rh-CdC), 184.2, 189.3 (d, JRhC ) 29 Hz). IR (KBr, cm-1) ν
1706. Anal. Calcd for C36H41N2O8Rh: C, 59.02; H, 5.64; N,
3.82. Found: C, 58.93; H, 5.77; N, 3.82. 6-dm: 1H NMR (300
MHz, CDCl3) 1.42 (s, 6H, Me), 1.49 (s, 6H, Me), 1.91 (s, 3H,
OCOMe), 2.54 (s, 6H, Me), 2.88 (s, 3H, CO2Me), 3.68 (s, 3H,
CO2Me), 4.39 (d, J ) 8.4 Hz, 2H, CH2), 4.47 (d, J ) 8.4 Hz, 2H,
CH2), 6.69 (s, 1H), 7.31-7.39 (m, 3H, C6H5), 8.00-8.04 (m, 2H,
C6H5). 13C{1H} NMR (75 MHz, CDCl3) δ 18.9, 23.8, 26.8, 49.9,
52.0, 65.4, 82.4, 87.1 (CCPh), 92.8 (CCPh), 124.9, 127.1, 127.21,
127.22, 127.7, 132.1, 139.7, 161.0, 161.1, 170.8 (d, JRhC ) 4.5
Hz), 171.5 (Rh-CdC), 174.9 (d, JRhC ) 34 Hz, Rh-CdC), 184.8,
189.9 (d, JRhC ) 28 Hz). IR (KBr, cm-1) ν 1712. Anal. Calcd for
C34H37N2O8Rh: C, 57.96; H, 5.29; N, 3.98. Found: C, 57.82; H,
5.35; N, 3.51.
Dimethyl 2-(Ethoxycarbonylethynyl)maleate (4k-Z). 3% yield,
yellow oil. 1H NMR (300 MHz, CDCl3) δ 1.34 (t, J ) 7.2 Hz, 3H,
Et), 3.81 (s, 3H, CO2Me), 3.88 (s, 3H, CO2Me), 4.29 (q, J ) 7.2
Hz, 2H, Et), 6.59 (s, 1H, CCH). 13C{1H} NMR (75 MHz, CDCl3)
δ 14.2, 52.7, 53.5, 62.7, 78.7, 86.2, 125.1, 134.9, 152.5, 162.4,
163.7. IR (KBr, cm-1) ν 2221, 1729, 1717. HR-MS: calcd for
C11H13O6 (MH+), 241.0707; found, 241.0712.
Isotope Labeling Experiments. To a mixture of 2a-d1 (155 mg,
1.5 mmol, 98%-d) and 1-ip (5.7 mg, 0.010 mmol) in toluene (4.0
mL) or toluene-d8 (1.0 mL) was added 3 (142 mg, 1.0 mmol) at
100 °C under a hydrogen atmosphere. The mixture was stirred at
100 °C for 4 h. After concentration, the residue was analyzed by
1H NMR spectroscopy.
Reaction of 6-ip with Phenylacetylene (2a). An NMR sample
tube was charged with 6-ip (2.0 mg, 0.0028 mmol), 2a (1.4 mg,
0.014 mmol), and C6Me6 (0.2 mg) as an internal standard with C6D6
Reaction of 1 with Phenylacetylene (2a). A mixture of 1-ip
(27.8 mg, 0.050 mmol) and 2a (25.5 mg, 0.25 mmol) in toluene
(2.0 mL) was stirred at 60 °C for 24 h under an argon atmos-
phere. After concentration of the solvent, the residue was puri-
fied by column chromatography on silica gel with hexane/ethyl
acetate (1:1) as an eluent to give 5-ip (25.7 mg, 0.044 mmol,
87%). The preparation procedure of 5-dm was similar to that of
5-ip (72%). 5-ip: 1H NMR (300 MHz, CDCl3) δ 0.85 (d, J )
6.6 Hz, 3H, CHMe2), 0.96 (d, J ) 7.2 Hz, 3H, CHMe2), 1.06
(d, J ) 7.2 Hz, 3H, CHMe2), 1.11 (d, J ) 6.6 Hz, 3H, CHMe2),
1.97 (s, 3H, OAc), 1.97-2.51 (m, 2H), 2.53 (s, 3H, Me), 2.55
(s, 3H, Me), 4.08 (m, 1H), 4.37 (m, 1H), 4.53-4.78 (m, 4H), 6.70
(s, 1H), 6.96-7.09 (m, 5H, C6H5). 13C{1H} NMR (75 MHz,
CDCl3) δ 14.8, 16.5, 19.0, 19.1, 19.6, 24.0, 28.9, 30.5, 66.4, 67.3,
1
(0.6 mL). The tube was heated at 80 °C for 9 h. The H NMR
spectrum showed the formation of 4a and 5-ip in 56% and 61%
yield, respectively.
X-ray Diffraction Study. Single crystals of 5-dm and 6-dm
suitable for X-ray diffraction study were obtained from CHCl3/
ether solution at room temperature. The diffraction data were
collected on a Brucker SMART APEX CCD diffractometer with
graphite monochromated Mo KR radiation (λ ) 0.71073 Å). An
empirical absorption correction was applied by using SADABS.
The structure was solved by direct method and refined by full-
matrix least-square on F2 using SHELXTL. All non-hydrogen atoms
of the rhodium complex were refined with anisotropic displacement
parameters. All hydrogen atoms were located on calculated positions
and refined as rigid groups. CCDC-642228 and 642229 contain
the supplementary crystallographic data for complexes 5-dm and
6-dm, respectively. Refinement details for 5-dm: empirical formula
70.4, 71.7, 86.9 (d, JRhC ) 53 Hz, Rh-CCPh), 102.0 (d, JRhC
)
9.7 Hz, Rh-CCPh), 124.4, 126.6, 126.6, 127.2, 127.8, 131.2, 140.2,
171.8 (d, JRhC ) 5.1 Hz), 172.5 (d, JRhC ) 5.1 Hz), 185.4, 186.6
(d, JRhC ) 25 Hz). IR (KBr, cm-1) ν 2119. Anal. Calcd for
C30H35N2O4Rh: C, 61.02; H, 5.97; N, 4.74. Found: C, 61.07; H,
6.03; N, 4.72. 5-dm: 1H NMR (300 MHz, CDCl3) δ 1.45 (s, 6H,
Me), 1.62 (s, 6H, Me), 1.93 (s, 3H, OAc), 2.53 (s, 6H, Me), 4.45
(d, J ) 8.4 Hz, 2H, CH2), 4.55 (d, J ) 8.4 Hz, 2H, CH2), 6.67 (s,
1H), 6.94-7.09 (m 5H, C6H5). 13C{1H} NMR (75 MHz, CDCl3)
δ 19.0, 24.2, 26.7, 27.8, 65.0, 82.2, 86.5 (d, JRhC ) 52 Hz,
Rh-CCPh), 102.7 (d, JRhC ) 9.2 Hz, Rh-CCPh), 124.5, 127.0,
127.2, 127.4, 128.2, 131.1, 140.1, 170.9 (d, JRhC ) 5.2 Hz), 186.0,
186.8 (d, JRhC ) 26 Hz). IR (KBr, cm-1) ν 2111. Anal. Calcd for
C28H31N2O4Rh: C, 59.79; H, 5.56; N, 4.98. Found: C, 59.24; H,
5.50; N, 4.47.
C32.50H45.25Cl3N2O4.50Rh; Mr ) 745.22; temperature 173(2) K;
crystal system triclinic; space group P21/n; a ) 17.272(11), b )
9.691(6), c ) 20.140(12) Å, â ) 94.441(13)°, V ) 3361(4) Å3, Z
) 4, Fcalcd ) 1.473 Mg/m3, µ ) 0.787 mm-1, F(000) ) 1545, crystal
size ) 0.40 × 0.40 × 0.10 mm3, θ range ) 2.33-27.47°; index
ranges, -18 e h e 22, -12 e k e 12, -26 e l e 26; reflections
collected 22 252; independent reflections 7592 [R(int) ) 0.0611];
completeness to θ ) 27.47°, 98.6%; max/min transmission
1.000000/0.668673; data/restraints/parameters 7592/0/404; good-
ness-of-fit on F2 1.061; final R indices [I > 2σ(I)], R1 ) 0.0543,
wR2 ) 0.1197; R indices (all data), R1 ) 0.0789, wR2 ) 0.1295;
largest diff. peak/hole 0.840 and -0.850 e Å-3. Refinement details
for 6-dm: empirical formula C37H44N2O8Rh; Mr ) 747.65; tem-
perature 173(2) K; crystal system triclinic; space group P-1; a )
9.437(10), b ) 9.469(11), c ) 19.68(2) Å, R ) 89.08(2)°, â )
84.11(3)°, γ ) 86.76(2)°, V ) 1746(3) Å3, Z ) 2, Fcalcd ) 1.422
Reaction of 5 with Dimethyl Acetylenedicarboxylate (3). A
mixture of 5-ip (54.3 mg, 0.090 mmol) and 3 (13.1 mg, 0.090
mmol) in toluene (2.0 mL) was stirred at room temperature for 4
h under an argon atmosphere. After concentration of the solvent,
the residue was purified by column chromatography on silica gel