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added in one portion. The suspension was placed inside a sonica-
tion bath at 508C for 2 h. After cooling to room temperature, the
mixture was filtered through Celite and the solvent was evaporat-
ed in vacuo. The dark-orange oily residue was taken up in CH2Cl2
and filtered again to remove any remaining silver salts. After re-
moving the solvent in vacuo, the dark-orange oil was triturated
with diethyl ether. A colorless solid precipitated and was filtered
off. The solid was washed with cold diethyl ether to remove col-
ored impurities. The product was isolated in 76% yield (0.360 g).
1H NMR (400 MHz, CDCl3): d=13.6 (s, 1H, CHCMe3, 1JCH =121 Hz),
3.86 (s, 6H, NHC-CH3), 1.30 (s, 9H, C(CH3)3), 1.26 ppm (s, 9H,
CH(CH3)3); 19F NMR (376 MHz, C6D6): d=ꢀ162.8 (br s), ꢀ167.99 (br
s), ꢀ175.11 (br s), 176.97 ppm (br s); 13C NMR (100 MHz, CDCl3): d=
302.2 (CHCMe3), 186.6 (CNcarbene), 142.1 (Caryl), 139.6 (Caryl), 139.3
(Caryl), 136.9 (Caryl), 133.7 (Caryl), 131.4 (Caryl), 118.5 (Cl-C=C-Cl), 71.0
(N-C-Me3), 46.4 (Mo=CH-C-Me3), 38.1 (NHC-CH3), 31.3 (C-CH3),
6.81 Hz), 0.84 (d, 6H, CH3, J=6.86 Hz), 0.63 (d, 3H, CH3, J=6.74 Hz),
0.16 ppm (d, 3H, CH3, J=6.80 Hz); 19F NMR (376 MHz, CD2Cl2): d=
ꢀ77.94 ppm (s, CF3SO3); 13C NMR (100 MHz, CD2Cl2): d=316.9
(CHMe2Ph), 205.9 (CNcarbene), 152.2 (Caryl), 151.9 (Caryl), 149.3 (Caryl),
147.4 (Caryl), 146.5 (Caryl), 145.7 (Caryl), 137.2 (Caryl), 130.3 (Caryl), 129.7
(Caryl), 128.5 (Caryl), 128.4 (Caryl), 126.9 (Caryl), 126.7 (Caryl), 126.6 (Caryl),
126.4 (Caryl), 125.3 (Caryl), 123.2 (Caryl), 120.9 (Caryl), 120.6 (Caryl), 119.9
(q, CF3, J=319 Hz), 117.5 (Caryl), 55.6 (NCH), 54.9 (NCH), 49.4
(CMe2Ph), 34.8, 29.7, 28.7, 28.5, 26.6, 26.1, 25.9, 24.3, 23.4, 22.7,
21.5 ppm; elemental analysis calcd. (%) for C44H54F3MoN3O4S: C
60.47, H 6.23, N 4.81; found: C 60.52, H 6.23, N 4.85. For elemental
analysis, the sample was ground and dried in vacuo to remove the
solvent.
Mo(N-2,6-Me2-C6H3)(N-mesityl-N’-O-C6H4)imidazolidin-2-ylide-
ne)(CHCMe2Ph)(OTf) (17)
31 ppm
(C-CH3);
elemental
analysis
(%)
calcd.
for
C26H25Cl2F10MoN3O2: C 40.64, H 3.28, N 5.47; found: C 40.63, H 3.30,
N 5.63.
3-(2-Hydroxyphenyl)-1-mesityl-4,5-dihydro-1H-imidazol-3-ium tetra-
fluoroborate (0.030 g, 0.086 mmol) and lithium hexamethyldisila-
zide (LiHMDS, 0.027 g, 0.163 mmol) were suspended in benzene
and stirred for 2 h at room temperature. The precipitate was fil-
tered off and the filtrate was added dropwise to a solution of
Mo(N-Ad)(IMesH2)(CHCMe2Ph)(OTf)2 (15)
Mo(N-Ad)(CHCMe2Ph)(OTf)2(DME) (0.060 g, 0.078 mmol) was sus-
pended in toluene and cooled to ꢀ308C. 1,3-Bis(2,4,6-trimethyl-
phenyl)-2-imidazolidin-2-ylidene (0.024 g, 0.078 mmol) was dis-
solved in toluene, cooled to ꢀ308C, and added to the suspension,
which was stirred for 3 h. The solvent was removed and the resi-
due recrystallized in CH2Cl2/n-pentane. The product was isolated in
55% yield (0.071 g). 1H NMR (400 MHz, CD2Cl2): d=13.49 (major
Mo(N-2,6-Me2-C6H3)(CH2CMe2Ph)(OSO2CF3)2·(DME)
(0.060 g,
0.086 mmol) in benzene (5 mL). The reaction mixture was stirred
for 3 h at room temperature and then filtered through Celite. The
solvent was removed in vacuo and the residue was dissolved in
a minimum amount of CH2Cl2, a few drops of n-pentane were
added, and the product was crystallized at ꢀ358C and obtained as
yellow crystals in 49% yield. 1H NMR (400 MHz, CD2Cl2): d=14.46
(anti isomer, 40%) (s, 1H, CHCMe2Ph, 1JCH =147 Hz), 12.81 (syn
isomer, 60%) (s, 1H, CHCMe2Ph, 1JCH =116 Hz), 7.31–7.13 (m, 7H,
ArH), 7.11–7.02 (m, 2H, ArH), 7.01–6.76 (m, 3H, ArH), 6.70 (anti
isomer), 6.63 (syn isomer) (br s, 1H, ArH), 6.14 (syn isomer), 6.02
(anti isomer) (br s, 1H, ArH), 4.44–4.15 (m, 2H, CH2), 2.30 (s, CH3),
2.22 (s, 3H, CH3), 2.07 (s, CH3), 2.05 (s, 3H, CH3), 1.98 (s, CH3), 1.84
(s, CH3), 1.70 (s, CH3), 1.69 (s, CH3), 1.57 (s, CH3), 1.44 (s, CH3), 1.38 (s,
CH3), 1.30 ppm (s, CH3); 19F NMR (376 MHz, CD2Cl2): d=ꢀ78.13 (syn
isomer) (s, CF3SO3), ꢀ78.21 ppm (anti isomer) (s, CF3SO3); 13C NMR
(100 MHz, CD2Cl2): d=330.2 (anti isomer) (CHMe2Ph), 309.3 (syn
isomer) (CHMe2Ph), 210.4 (anti isomer) (CNcarbene), 208.1 (syn isomer)
(CNcarbene), 154.8 (Caryl), 154.6 (Caryl), 153.6 (Caryl), 151.8 (Caryl), 147.8
(Caryl), 147.7 (Caryl), 140.3 (Caryl), 138.9 (Caryl), 136.4 (Caryl), 136.1 (Caryl),
136.0 (Caryl), 135.6 (Caryl), 135.5 (Caryl), 135.3 (Caryl), 134.6 (Caryl), 130.12
(Caryl), 130.07 (Caryl), 130.0 (Caryl), 129.7 (Caryl), 129.4 (Caryl), 129.3 (Caryl),
128.2 (Caryl), 127.8 (Caryl), 127.7 (Caryl), 127.3 (Caryl), 126.74 (Caryl),
126.68 (Caryl), 126.6 (Caryl), 126.5 (Caryl), 126.1 (Caryl), 126.0 (Caryl), 121.0
(Caryl), 120.7 (Caryl), 120.4 (Caryl), 120.1 (Caryl), 120.03 (q, CF3, J=
319 Hz), 119.98 (q, CF3, J=320 Hz), 117.8 (Caryl), 117.3 (Caryl), 54.7
(NCH), 54.2 (NCH), 51.7 (NCH(CH2)2), 51.3 (NCH), 49.7 (CMe2Ph), 49.5
(CMe2Ph), 32.4 (CH3), 29.24 (CH3), 29.18 (CH3), 27.3 (CH3), 21.1 (CH3),
21.0 (CH3), 20.5 (CH3), 19.0 (CH3), 18.5 (CH3), 18.0 (CH3), 17.8 (CH3),
17.3 ppm (CH3); elemental analysis calcd. (%) for C37H40F3MoN3O4S:
C 57.29, H 5.20, N 5.42; found: C 57.18, H 5.30, N 5.52. For elemen-
tal analysis, the sample was ground and dried in vacuo to remove
the solvent.
1
isomer, 95%) (s, 1H, CHCMe2Ph, JCH =120 Hz), 11.31 (minor isomer,
5%), 7.48–7.21 (m, 5H, ArH), 6.70 (s, 2H, ArH), 6.63 (s, 2H, ArH),
4.20–3.79 (m, 4H, CH2NC), 2.51–1.39 ppm (m, 39H, CH3); 19F NMR
(376 MHz, CD2Cl2): d=ꢀ76.31 (s, CF3SO3), ꢀ77.38 ppm (s, CF3SO3);
13C NMR (100 MHz, CD2Cl2): d=329.9 (CHCMe2Ph, major isomer),
318.1 (CHCMe2Ph, minor isomer), 211.8 (CNcarbene), 211.7 (CNcarbene
,
minor isomer), 149.9, 147.2, 140.7, 136.9, 130.8, 130.6, 130.2, 128.5,
127.9, 126.8, 126.6, 126.4, 126.3, 119.7 (q, CF3, J=320 Hz), 84.2
(NCH), 80.5 (NCH, minor isomer), 55.4 (CMe2Ph), 52.8, 52.6, 51.8,
42.8, 42.7, 35.8, 35.5, 31.0, 30.3, 30.1, 30.0, 29.6, 22.8, 21.3, 18.9,
17.9 ppm; elemental analysis calcd. (%) for C43H53F6MoN3O6S2: C
52.59, H 5.44, N 4.28; found: C 52.32, H 5.82, N 4.30.
Mo(N-2,6-(iPr)2-C6H3)(N-2,6-(iPr)2-C6H3)-N’-O-
C6H4)imidazolidin-2-ylidene)(CHCMe2Ph)(OTf) (16)
1-(2,6-Diisopropylphenyl)-3-(2-hydroxyphenyl)-4,5-dihydro-1H-imi-
dazol-3-ium tetrafluoroborate (0.031 g, 0.076 mmol) and lithium
hexamethyldisilazide (LiHMDS, 0.025 g, 0.152 mmol) were suspend-
ed in benzene (5 mL) and stirred for 2 h at room temperature. The
precipitate was filtered off and the filtrate was added dropwise to
a
solution of Mo(N-2,6-(iPr)2-C6H3)(CHCMe2Ph)(OSO2CF3)2·(DME)
(0.060 g, 0.076 mmol) in benzene (5 mL). The reaction mixture was
stirred for 3 h at room temperature and then filtered through
Celite. The solvent was removed in vacuo and the residue was dis-
solved in a minimum amount of CH2Cl2. The product was crystal-
lized at ꢀ358C and obtained as yellow crystals in 59% isolated
1
1
yield. H NMR (400 MHz, CD2Cl2): d=13.64 (s, 1H, CHCMe2Ph, JCH
=
(N-2,6-(iPr)2-C6H3)-N’-O-C6H4)imidazolidin-2-ylidene)(CHC-
119 Hz), 7.50–7.41 (m, 2H, ArH), 7.28–7.18 (m, 5H, ArH), 7.17–7.01
(m, 7H, ArH), 6.95 (dd, 1H, ArH, J=7.79, 1.32 Hz), 4.60–4.47 (m, 1H,
CH), 4.38–4.26 (m, 1H, CH), 4.07–3.94 (m, 1H, CH), 3.93–3.80 (m,
1H, CH), 3.72–3.56 (m, 2H, CH), 2.68 (hept, 1H, CH, J=6.88 Hz),
2.51 (hept, 1H, CH, J=6.51 Hz), 1.14 (d, 6H, CH3, J=6.81 Hz), 1.03
(s, 3H, CH3), 0.98 (d, 3H, CH3, J=6.84 Hz), 0.95 (d, 3H, CH3, J=
Me2Ph)(OC6F5) (18)
A
solution
of
Mo(N-2,6-(iPr)2-C6H3)(N-2,6-(iPr)2-C6H3)-N’-O-
C6H4)imidazolidin-2-ylidene)(CHCMe2Ph)(OTf) (0.050 g, 0.057 mmol)
in C2H4Cl2 was cooled to ꢀ358C and lithium 2,3,4,5,6-pentafluoro-
phenolate (0.011 g, 0.0572 mmol) was added. The suspension was
ChemCatChem 2016, 8, 1 – 15
13
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