S. Bellemin-Laponnaz, L. H. Gade et al.
FULL PAPER
296 K): δ = 161.4 (NCO), 137.7, 129.7, 119.6 (CHimid), 75.9
C26H33F6N3OPRh (651.43): calcd. C 47.94, H 5.11, N 6.45; found
(CHoxa), 69.6 (CH2 oxa), 43.9 (NCH2), 33.6 [C(CH3)3], 25.7 C 47.66, H 5.51, N 6.30.
[C(CH3)3] ppm. MS (FAB) m/z (%): 226.1 [M + H3O]+ (30), 208.1
(η4-2,5-Norbornadiene)(1-{1-[(4S)-tert-butyl-4,5-dihydrooxazol-2-
[M + H]+ (100). FT-IR (KBr): ν = 1675 cm–1 (s, ν(C=N)).
˜
yl]methyl}-3-isopropylimidazole-2-ylidene)rhodium(I) Hexafluoro-
phosphate (2b): Similar procedure as the one for 2a. Reacting the
imidazolium salt 1b (127 mg, 0.32 mmol), [RhCl(nbd)]2 (74 mg,
0.16 mmol) and KHMDS (70 mg, 0.33 mmol) yielded a crude
product, which was diluted in CH2Cl2, filtered through celite, and
dried under vacuum to give 2b as a yellow solid (137 mg, yield
96 %). 1H NMR (600 MHz, CD2Cl2, 296 K): δ = 7.08 (d, 3J =
C11H17N3O2 (223.27): calcd. C 63.74, H 8.27, N 20.27; found C
63.60, H 8.21, N 20.12.
1-{1-[(4S)-tert-Butyl-4,5-dihydrooxazol-2-yl]methyl}-3-[bis(α-naph-
thyl)methyl]imidazolium Bromide (1f): The imidazole derivative
(553 mg, 2.7 mmol) and bromodinaphthalen-1-ylmethane (926 mg,
2.7 mmol) were placed in a Schlenk tube and dissolved in CH3CN
(15 mL). After reacting for 12 h at 60 °C, the solvent was evapo-
rated and the resulting solid was washed with Et2O (2ϫ5 mL) and
pentane (5 mL) and dried in vacuo to yield the imidazolium salt 1f
as an air-sensitive white powder (1.24 g, 84 %). 1H NMR
(600 MHz, CD2Cl2, 296 K): δ = 9.91 (br. s, 1 H, CHimid), 9.02 (s,
3
1.6 Hz, 1 H, CHimid), 6.94 (d, J = 1.6 Hz, 1 H, CHimid), 5.32 (br.
s, 1 H, NCH2), 4.92 (br. s, 1 H, NCH2), 4.88 (s, 1 H, CHnbd), 4.59
(m, 2 H, CHiPr+CHnbd), 4.46 (br. s, 1 H, CHnbd), 4.43 (t, 3J =
9.6 Hz, 1 H, CH2 oxa), 4.23 (br. s, 1 H, CH2 oxa), 4.07 (s, 1 H,
CHnbd), 3.91 (s, 1 H, CHnbd), 3.88 (s, 1 H, CHnbd), 3.53 (br. s, 1 H,
CHoxa), 1.47 (d, 3J = 8.0 Hz, 1 H, CH2 nbd), 1.41 (m, 4 H,
1 H, CHNp2), 8.18 (m, 2 H, CHNp), 7.94–7.93 (m, 5 H, 4CHNp
+
3
CHimid), 7.50–7.37 (m, 7 H, 4CHNp + CHimid), 6.97 (m, 2 H,
CH3 iPr+CH2 nbd), 1.33 (d, J = 3.4 Hz, 3 H, CH3 iPr), 0.85 [s, 9 H,
2
2
C(CH3)3] ppm. 13C{1H} NMR (150 MHz, CD2Cl2, 296 K): δ =
188.3 (m, N2C), 165.6 (NCO), 122.6, 117.7 (CHimid), 80.6 (CHnbd),
74.0 (CH2 oxa), 73.5 (CHoxa), 72.2 (CHnbd), 65.7 (CH2 nbd), 56.2
(CHnbd), 52.3 (NCHiPr/CHnbd), 47.7 (NCH2), 33.9 [C(CH3)3], 25.4
[C(CH3)3], 24.4, 23.4 (CH3 iPr) ppm. HR-MS (FAB+) m/z (%):
calcd. for C21H31N3ORh+ ([M – PF6]+) 444.152; found 444.152
CHNp), 5.34 (d, J = 16.2 Hz, 1 H, NCH2), 5.32 (d, J = 16.2 Hz,
2
3
1 H, NCH2), 4.22 (dd, J = 9.3, J = 9.3 Hz, 1 H, CH2 oxa), 4.08
2
3
3
3
(dd, J = 8.5, J = 8.5 Hz, 1 H, CH2 oxa), 3.79 (dd, J = 9.1, J =
9.1 Hz, 1 H, CHoxa), 0.78 [s, 9 H, C(CH3)3] ppm. 13C{1H} NMR
(150 MHz, CD2Cl2, 296 K): δ = 160.1 (NCO), 139.7 (N2C), 134.1,
132.6, 132.5, 132.0, 130.4, 130.4 (CNp), 130.3, 129.0, 127.6, 126.8,
126.3, 126.3, 125.3 (CHNp), 123.9 (CHimid), 123.5 (CHNp), 122.0
(CHimid), 75.5 (CHoxa), 70.3 (CH2 oxa), 61.5 (CHNp2), 46.3
(NCH2), 33.4 [C(CH3)3], 25.5 [C(CH3)3] ppm. 15N NMR (60 MHz,
CD2Cl2, 296 K): δ = 232.8 (Noxa), 189.6, 173.5 (Nimid) ppm. HR-
MS (FAB+) m/z (%): calcd. for C32H32N3O ([M – Br]+) 474.254;
( 1 0 0 ) . F T - I R ( K B r ) : ν = 1 6 5 4 c m – 1 ( m , ν ( C = N ) ).
˜
C21H31F6N3OPRh·0.5CH2Cl2 (631.83): calcd. C 40.87, H 5.10, N
6.65; found C 40.79, H 5.40, N 6.89.
(η4-2,5-Norbornadiene)(1-{1-[(4S)-tert-butyl-4,5-dihydrooxazol-2-
yl]methyl}-3-mesitylimidazole-2-ylidene)rhodium(I) Hexafluorophos-
phate (2c): Similar procedure as the one for 2a. Reacting the imid-
azolium salt 1c (147 mg, 0.32 mmol), [RhCl(nbd)]2 (74 mg,
0.16 mmol) and KHMDS (70 mg, 0.33 mmol) yielded 2c as a yel-
low solid (154 mg, yield 80 %). 1H NMR (600 MHz, CDCl3,
296 K): δ = 7.33 (d, 3J = 18.6 Hz, 1 H, CHimid), 7.08 (s, 1 H,
found 474.254 (100). FT-IR (KBr): ν = 1680 cm–1 (s, ν(C=N)).
˜
C32H32BrN3O (554.52): calcd. C 69.31, H 5.82, N 7.58; found C
69.18, H 5.75, N 7.40.
(η4-2,5-Norbornadiene)(1-{1-[(4S)-isopropyl-4,5-dihydrooxazol-2-
yl]methyl}-3-mesitylimidazole-2-ylidene)rhodium(I) Hexafluorophos-
phate (2a): To a solution of the imidazolium salt 1a (146 mg,
0.32 mmol) in THF (5 mL) was added a solution of KHMDS
(70 mg, 0.33 mmol) in THF (5 mL) at –78 °C. The resulting yellow
solution was stirred for 30 min and a solution of [Rh(nbd)Cl]2
(74 mg, 0.16 mmol) in THF (3 mL) was added. The mixture was
stirred and warmed to ambient temperature for 12 h. The orange-
red solution was then filtered and the volatiles were removed in
vacuo. The resulting orange solid was washed twice with an Et2O/
CH2Cl2 mixture (5:1, 2ϫ5 mL) and hexane (5 mL) to yield 2a as
3
CHMes), 6.92 (s, 1 H, CHMes), 6.74 (d, J = 18.6 Hz, 1 H, CHimid),
5.48 (d, 2J = 18.2 Hz, 1 H, NCH2), 5.00 (d, 3J = 18.2 Hz, 1 H,
3
3
NCH2), 4.92 (t, J = 3.7 Hz, 1 H, CHnbd), 4.56 (d, J = 6.7 Hz, 2
3
3
H, CH2 oxa), 4.39 (t, J = 3.9 Hz, 1 H, CHnbd), 3.96 (dd, J = 5.8,
3J = 5.8 Hz, 1 H, CHnbd), 3.84 (br. s, 1 H, CHnbd), 3.50 (br. s, 1 H,
3
CHnbd), 3.39 (t, J = 6.7 Hz, 1 H, CHoxa), 2.50 (br. s, 1 H, CHnbd),
2.37 (s, 3 H, CH3 p-Mes), 2.10 (s, 3 H, CH3 o-Mes), 1.92 (s, 3 H,
CH3 o-Mes), 1.25 (br. s, 2 H, CH2 nbd), 0.93 [s, 9 H, C(CH3)3] ppm.
1 3 C{1 H} NMR (150 MHz, CDCl3 , 296 K): δ = 175.5 [d,
1J(103Rh13C) = 58 Hz, N2C], 165.5 (NCO), 139.6, 135.7, 134.6,
134.5 (CMes), 129.2, 129.0 (CHMes), 122.8, 122.1 (CHimid), 82.6 [d,
1J(103Rh13C) = 6.6 Hz, CHnbd], 74.4 [d, 1J(103Rh13C) = 5.8 Hz,
CHnbd], 72.9 (CHoxa), 71.8 (CH2 oxa), 64.9 (CH2 nbd), 58.6 [d,
1J(103Rh13C) = 10.7 Hz, CHnbd], 58.8 [d, 1J(103Rh13C) = 11.1 Hz,
CHnbd], 52.6, 51.6 (CHnbd), 47.1 (NCH2), 33.7 [C(CH3)3], 25.2
[C(CH3)3], 21.2 (CH3 p-Mes), 18.3, 17.5 (CH3 o-Mes) ppm. HR-MS
(FAB+) m/z (%): calcd. for C27H35N3ORh+ ([M – PF6]+) 520.183;
1
a yellow solid (164 mg, yield 82%). H NMR (600 MHz, CD2Cl2,
263 K): δ = 7.29 (d, 3J = 1.9 Hz, 1 H, CHimid), 7.07 (s, 1 H, CHMes),
3
6.92 (s, 1 H, CHMes), 6.80 (d, J = 1.8 Hz, 1 H, CHimid), 5.25 (d,
2J = 17.8 Hz, 1 H, NCH2), 4.98 (d, 2J = 17.8 Hz, 1 H, NCH2), 4.74
(br. s, 1 H, CHnbd), 4.49 (t, 2/3J = 9.5 Hz, 1 H, CH2 oxa), 4.45 (dd,
3
2J = 9.4, J = 5.3 Hz, 1 H, CH2 oxa), 4.37 (br. s, 1 H, CHnbd), 3.95
(br. s, 1 H, CHnbd), 3.76 (br. s, 1 H, CHnbd), 3.58 (ddd, 3J = 9.6, 3,3J
= 5.0 Hz, 1 H, CHoxa), 3.55 (br. s, 1 H, CHnbd), 2.52 (br. s, 1 H,
CHnbd), 2.34 (s, 3 H, CH3 p-Mes), 2.09 (s, 3 H, CH3 o-Mes), 1.92 (s, 3
found 520.183 (100). FT-IR (KBr): ν = 1654 cm–1 (m, ν(C=N)).
˜
3
H, CH3 p-Mes), 1.23 (br. s, 2 H, CH2 nbd), 0.89 [d, J = 7.0 Hz, 3 H,
CH(CH3)2], 0.70 [d, 3J = 6.8 Hz, 3 H, CH(CH3)2] ppm. 13C{1H} Chloro(η4-2,5-Norbornadiene)(1-{1-[(4S)-isopropyl-4,5-dihydroox-
NMR (150 MHz, CD2Cl2, 263 K): δ = 174.6 [d, 1J(103Rh13C) =
58 Hz, N2C], 164.7 (NCO), 139.8, 136.0, 134.5, 134.2 (CMes), 129.0,
128.9 (CHMes), 122.9, 121.8 (CHimid), 80.7 [d, 1J(103Rh13C) =
azol-2-yl]methyl}-3-isopropylimidazole-2-ylidene)rhodium(I) (2d):
Similar procedure as the one for 2a. Reacting the imidazolium salt
1d (85 mg, 0.30 mmol), [RhCl(nbd)]2 (69 mg, 0.15 mmol) and
5.1 Hz, CHnbd], 73.2 (CHnbd), 71.4 (CH2 oxa), 68.9 (CHoxa), 67.7 KHMDS (66 mg, 0.33 mmol) gives a crude product that is crys-
(CH2 nbd), 60.8 [d, 1J(103Rh13C) = 10.4 Hz, CHnbd], 60.1 [d, tallized from a CH2Cl2/pentane mixture to yield 2d as a yellow
1
1J(103Rh13C) = 8.8 Hz, CHnbd], 52.8 (CHnbd), 51.9 (CHnbd), 46.9
solid (110 mg, yield 85%). H NMR (600 MHz, CDCl3, 263 K): δ
(NCH2), 31.7 [CH(CH3)2], 20.9 (CH3 p-Mes), 18.2 (CH3 o-Mes), 17.8 = 6.96 (s, 1 H, CHimid), 6.82 (s, 1 H, CHimid), 5.72 (sept, 3J =
[CH(CH3)2], 17.3 (CH3 o-Mes), 14.8 [CH(CH3)2] ppm. HR-MS
6.8 Hz, 1 H, NCHiPr), 5.49 (br. s, 1 H, NCH2), 5.44 (br. s, 1 H,
(FAB+) m/z (%): calcd. for C26H33N3ORh+ ([M – PF6]+) 506.167;
NCH2), 4.82 (br. s, 2 H, CHnbd), 4.33 (t, 2/3J = 9.1 Hz, 1 H,
found 506.174 (100). FT-IR (KBr): ν = 1663 cm–1 (m, ν(C=N)).
CH2 oxa), 4.07 (t, 2/3J = 8.2 Hz, 1 H, CH2 oxa), 3.98 (q, J = 7.8 Hz,
3
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498
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Eur. J. Inorg. Chem. 2009, 493–500