5646
J. Barluenga et al. / Journal of Organometallic Chemistry 691 (2006) 5642–5647
2H), 6.48 (d, J = 15.1 Hz, 2H), 7.08 (s, 4H), 7.13 (s, 2H), 8.45
(d, J = 15.1 Hz, 1H. 13C NMR (CDCl3): 18.7 (CH3), 21.2
(CH3), 69.7 (CH3), 70.6 (CH), 72.6 (CH), 76.6 (CH), 78.7
(C), 122.7 (CH), 128.7 (CH), 133.5 (C), 136.2 (CH), 136.7
(C), 138.1 (C), 171.1 (CH), 187.5 (C, d, J(Rh,C) = 85.9 Hz),
189.3 (C, d, J(Rh,C) = 37.4 Hz), 304.3 (C, d, J(Rh,C) =
34.4 Hz) ); IR (CH2Cl2): m 3054, 2986, 1946, 1599, 1421,
1265, 895, 739 cmÀ1. Anal. Calcd for C36H38ClFeN2O2Rh:
C, 59.65, 5.28. Found: C, 59.40, H, 5.19%.
J = 3.5 y 1.9 Hz, 1H), 6.92 (d, J = 14.7 Hz, 1H), 7.02 (s,
4H), 7.09 (s, 2H), 7.40 (bs, 1H), 7.93 (d, J = 14.7 Hz,
1H). 13C NMR (CDCl3): 18.6 (CH3), 21.1 (CH3), 41.1
(CH3), 51.5 (CH3), 112.0 (CH), 114.6 (CH), 122.2 (CH),
126.9 (CH), 128.5 (CH), 136.2 (C), 136.9 (C), 137.8 (C),
142.4 (CH), 143.9 (CH), 152.7 (C), 188.1 (C, d,
J(Rh,C) = 86.5 Hz), 189.6 (C, d, J(Rh,C) = 39.4 Hz),
243.5 (C, d, J(Rh,C) = 32.1 Hz); IR (CH2Cl2): m 3154,
2921, 1932, 1621, 1485, 1266, 907, 733 cmÀ1. Anal. Calcd
for C31H35ClN3O2Rh: C, 60.05; H, 5.69. Found: C,
59.87; H, 5.44%.
3.1.5. (Carbonyl)(chloro)(1,3-dimesitylimidazol-2-
ylidene)(methoxybencylidene) rhodium(I) (3e)
1H NMR (CDCl3): 2.28 (s, 12H), 2.43 (s, 6H), 4.73 (s, 3H),
7.07(s, 4H),7.15(s, 2H),7.19-7.26(m, 2H),7.43–7.48(m, 1H),
8.03 (d, J = 8.1 Hz, 2H). 13C NMR (CDCl3): 18.6 (CH3), 21.2
(CH3), 68.8 (CH3, d, J(Rh,C) = 2.3 Hz), 122.8 (CH), 127.6
(CH), 128.7 (CH), 132.8 (CH), 134.0 (CH), 136.0 (C), 136.4
(C), 138.3 (C), 145.2 (C), 186.9 (C, d, J(Rh,C) = 85.0 Hz),
188.0 (C, d, J(Rh,C) = 36.6 Hz), 313.9 (C, d, J(Rh,C) =
34.9 Hz); IR (CH2Cl2): m 3054, 2986, 1954, 1642, 1422, 1265,
895, 738 cmÀ1. Anal. Calcd for C30H32ClN2O2Rh: C, 60.97;
H, 5.46. Found: C, 60.70; H, 5.25%.
3.2. Thermal behaviour of complex 3a
A solution of complex 3a (62 mg, 0.1 mmol) in toluene
(2 mL) was heated at 60 °C. The mixture was stirred at this
temperature until disappearance of the starting complex
(checked by TLC, 4 h). The solvent was then removed
and the resulting residue was subjected to flash chromatog-
raphy (SiO2, 5:1 hexane:ethyl acetate) yielding the dimers 4
and 5. The spectroscopic data of compound 5 were identi-
cal to those previously reported in the literature [18].
3.1.6. (Carbonyl)(chloro)(1,3-dimesitylimidazol-2-
ylidene)[methoxy(4-methoxy)bencylidene] rhodium(I)
(3f)
3.2.1. (Carbonyl)(l-chloro)(1,3-dimesitylimidazol-2-
ylidene) rhodium(I) dimer (4).
1H NMR (CDCl3): 2.14 (s, 24H), 2.35 (s, 12H), 6.90–
6.96 (bs, 12H). 13C NMR (CDCl3): 18.7 (CH3), 21.1
(CH3), 123.3 (CH), 128.7 (CH), 135.2 (C), 138.3 (C),
175.0 (C, d, J(Rh,C) = 60.8 Hz), 184.5 (C, d,
J(Rh,C) = 84.8 Hz); IR (CH2Cl2): m 3053, 2986, 1956,
1H NMR (CDCl3): 2.38 (s, 12H), 2.45 (s, 6H), 3.85 (s, 3H),
4.66 (s, 3H), 6.71 (d, J = 9.0 Hz, 2H), 7.09 (s, 4H), 7.17 (s,
2H), 8.06 (d, J = 9.0 Hz, 2H) 13C NMR (CDCl3): 18.6
(CH3), 21.2 (CH3), 55.4 (CH3), 68.0 (CH3), 112.8 (CH),
122.7 (CH), 128.7 (CH), 135.6 (CH), 136.0 (C), 136.5 (C),
138.2 (C), 139.3 (C), 164.4 (C), 187.2 (C, d, J(Rh,C)
= 85.9 Hz), 188.6 (C, d, J(Rh,C) = 37.4 Hz), 307.4 (C, d,
J(Rh,C) = 35.4 Hz); IR (CH2Cl2): m 3054, 2986, 1950,
1597, 1421, 1264, 896, 733 cmÀ1. Anal. Calcd for C31H34-
ClN2O2Rh: C, 59.96; H, 5.52. Found: C, 59.74; H, 5.36%.
1643, 1421, 1265, 895, 738 cmÀ1
. Anal. Calcd for
C44H48Cl2N4O2Rh2: C, 56.13; H, 5.14. Found: C, 55.85;
H, 5.07%. HR-MS; calcd.: 940.1276, found: 940.1265.
3.3. Rh(I)-catalyzed [3 + 2]-cyclization reaction of alkenyl
Fischer carbene complex 1c with methyl propiolate
3.1.7. (Carbonyl)(chloro)(1,3-dimesitylimidazol-2-
ylidene)(1-dimethylamino-3-phenyl-2-propenylidene)
rhoidum(I) (3g)
To a solution of carbene complex 1c (164 mg, 0.5 mmol)
and methyl propiolate (126 mg, 1.5 mmol) in CH2Cl2
(5 mL) was added the complex 2 (28 mg, 0.05 mmol) and
AgSbF6 (17 mg, 0.05 mmol). The mixture was stirred at
room temperature until disappearance of the starting car-
bene complex (checked by TLC, 12 h). The solvent was
then removed and the resulting residue was subjected to
flash chromatography (SiO2, 15:1 hexane:ethyl acetate) to
give pure compound 6.
1H-RMN(CDCl3): 2.34 (s, 12H), 2.42 (s, 6H), 3.25 (s,
3H), 3.65 (s, 3H), 7.06 (d, J = 15.0 Hz, 1H), 7.08 (s, 4H),
7.14 (s, 2H), 7.37 (s, 5H), 8.20 (d, J = 15.0 Hz, 1H). 13C-
RMN(CDCl3): 18.6 (CH3), 21.1 (CH3), 41.2 (CH3), 51.5
(CH3), 122.3 (CH), 128.2 (CH), 128.4 (CH), 128.6 (CH),
129.2 (CH), 129.4 (CH), 136.2 (C), 136.4 (C), 136.9 (C),
138.0 (C), 156.7 (CH), 188.1 (C, d, J(Rh,C) = 85.9 Hz),
189.6 (C, d, J(Rh,C) = 39.4 Hz), 245.4 (C, d, J(Rh,C)
= 32.3 Hz); IR (CH2Cl2): m 3053, 2986, 1931, 1611, 1421,
1265, 895, 737 cmÀ1. Anal. Calcd for C33H37ClN3ORh: C,
62.91; H, 5.92. Found: C, 62.69; H, 5.77%.
3.3.1. 4-(2-Furyl)-3-methoxycarbonyl-2-cyclopentenone (6)
1H NMR (CDCl3): 2.66 (dd, J = 18.9 and 2.3 Hz, 1H),
2.93 (dd, J = 18.9 and 7.1 Hz, 1H), 3.80 (s, 3H), 4.54 (td,
J = 7.1 and 2.3 Hz, 1H), 6.13 (d, J = 3.3 Hz, 1H), 6.30
(dd, J = 3.1 and 1.8 Hz, 1H), 6.82 (d, J = 2.0 Hz, 1H),
7.29–7.31 (m, 1H). 13C NMR (CDCl3): 39.0 (CH), 42.6
(CH2), 52.6 (CH3), 106.4 (CH), 110.6 (CH), 138.1 (CH),
142.0 (CH), 152.3 (C), 162.3 (C), 164.0 (C), 207.1 (C).
Anal. Calcd for C11H10O4: C, 64.07; H, 4.89. Found: C,
63.99; H, 4.96%.
3.1.8. (Carbonyl)(chloro)(1,3-dimesitylimidazol-2-
ylidene)[1-dimethylamino-3-(2-furyl)-2-propenylidene]
rhodium(I) (3h)
1H NMR (CDCl3): 2.28 (s, 12H), 2.37 (s, 6H), 3.19 (s,
3H), 3.60 (s, 3H), 6.39 (d, J = 3.3 Hz, 1H), 6.43 (dd,