Organometallics
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CH), 6.87−7.68 (m, 11H, Ar-H). 13C{1H} NMR (d5-pyridine, 77.5
MHz, 298 K): δ 24.7, 25.1, 29.1, 94.9 (β-CH), 111.2 (MgCαCβ),
122.0 (MgCαCβ), 124.4 (m-Ar-C), 125.8 (p-Ar-C), 126.2 (p-Ph-C),
128.6 (m-Ph-C), 129.0 (i-Ph-C), 132.3 (o-Ph-C), 143.3 (o-Ar-C),
145.7 (i-Ar-C), 169.4 (NCMe). IR (KBr): 3057, 2959, 2923, 2046,
1559, 1539, 1521, 1465, 1457, 1437, 1403, 1364, 1317, 1259, 1180,
1069, 1059, 1019, 929, 852, 793, 763, 755, 692 cm−1. Anal. Calcd for
C74H92Mg2N4 (Mw = 1086.2): C, 81.83; H, 8.54; N, 5.16. Found: C,
81.79; H, 8.60; N, 5.08.
unsatisfactory elemental analysis, despite NMR data showing a single
clean product. NMR spectra are provided to prove purity.
Synthesis and Characterization of Calcium Acetylides
[LCaCCR]2. [LCa{N(SiMe3)2}(THF)] (0.73 mmol, 500 mg) was
weighed into a Schlenk tube, dissolved in toluene (5.00 mL), and then
treated with alkyne (0.73 mmol). The resulting mixture was stirred at
room temperature for 2 h. The crystalline product [LCaCCR]2 was
isolated after cooling to 4 °C for 48 h.
1
[LCaCCCH2OPh]2 (9). Yield: 0.30 g, 0.51 mmol, 70%. H NMR
(C6D6, 300 MHz, 298 K): δ 1.18 (d, 12H, iPr-CH3, 3J = 6.8 Hz), 1.27
(d, 12H, iPr-CH3, 3J = 6.8 Hz), 1.70 (s, 6H, NCCH3), 3.30 (sept, 4H,
iPr-CH, 3J = 6.8 Hz), 3.89 (s, 2H, OCH2), 4.95 (s, 1H, β-CH), 6.86−
6.94 (m, 3H, Ar/Ph-H), 7.13−7.21 (m, 7H, Ar/Ph-H). 13C{1H} NMR
(C6D6, 75 MHz, 298K): δ 20.8, 24.3, 28.6, 60.0 (OCH2), 94.3 (β-CH),
106.3 (CaCαCβ), 115.5 (o-Ph-C), 124.0 (p-Ph-C), 124.2 (m-Ar-C),
124.8 (p-Ar-C), 130.0 (m-Ph-C), 142.4 (o-Ar-C), 146.1 (i-Ar-C), 148.6
(CaCαCβ), 156.6 (i-Ph-C), 165.6 (NCMe). IR (KBr): 3051, 3017,
2961, 2922, 2863, 2074, 1599, 1590, 1547, 1510, 1492, 1461, 1431,
1406, 1365, 1314, 1265, 1251, 1225, 1201, 1167, 1099, 1015, 975, 923,
[LMgCC(4-MePh)]2 (5). NMR scale: 40 mg of [LMg{N-
(SiMe3)2}] (66.4 μmol) and 7.71 mg of p-tolylacetylene (66.4
μmol) were heated in toluene at 80 °C for 24 h. NMR data showed
quantitative conversion to 5. Colorless crystals were isolated from the
NMR tube (34 mg, 61.0 μmol, 92% yield). 1H NMR (d5-pyridine, 300
MHz, 298 K): δ 1.13 (d, 12H, 3J = 6.9 Hz, iPr-CH3), 1.36 (d, 12H, 3J =
i
6.9 Hz, Pr-CH3), 1.91 (s, 6H, NCCH3), 2.12 (s, 3H, tol-CH3), 3.46
(sept, 4H, 3J = 6.8 Hz, iPr-CH), 5.11 (s, 1H, β-CH), 6.92 (d, 2H, 3J =
7.8 Hz, o-tol-H), 7.29−7.30 (m, 6H, Ar-H), 7.42 (d, 2H, 3J = 7.8 Hz, o-
tol-H). 13C{1H} NMR (d5-pyridine, 77.5 MHz, 298 K): δ 21.6 (tol-
CH3), 24.6, 24.8, 25.1, 29.1, 94.8 (β-CH), 115.3 (MgCαCβ), 124.4
(m-Ar-C), 125.4 (MgCαCβ), 125.8 (p-Ar-C), 129.2 (m-tol-C), 132.3
(o-tol-C), 135.3 (p-tol-C), 138.1 (i-tol-C), 143.2 (o-Ar-C), 145.7 (i-Ar-
C), 169.3 (NCMe). IR (KBr): 3062, 2961, 2923, 2866, 2052, 1622,
1540, 1521, 1463, 1437, 1404, 1363, 1315, 1262, 1176, 1102, 1057,
1020, 930, 850, 818, 794, 761, 751, 710 cm−1. Anal. Calcd for
C76H96Mg2N4 (Mw = 1114.2): C, 81.92; H, 8.68; N, 5.03. Found: C,
82.01; H, 8.59; 5.13.
828, 784, 751, 690 cm−1. Anal. Calcd for C76H96Ca2N4O2 (Mw
=
1177.8): C, 77.50; H, 8.22; N, 4.76. Found: C, 77.42; H, 8.34; N, 4.64.
[LCaCCCH2NMe2]2 (10). Yield: 0.28 g, 0.52 mmol, 71%. 1H NMR
(C6D6, 300 MHz, 298 K): δ 1.21 (d, 12H, iPr-CH3, 3J = 6.8 Hz), 1.23
i
3
(d, 12H, Pr-CH3, J = 6.8 Hz), 1.66 (s, 6H, NCCH3), 1.89 (s, 6H,
i
3
NCH3), 2.57 (s, 2H, NCH2), 3.30 (sept, 4H, Pr-CH, J = 6.8 Hz),
4.80 (s, 1H, β-CH), 7.16−7.18 (m, 6H, Ar-H); 13C{1H} NMR (C6D6,
75 MHz, 298 K): δ 20.8, 24.5, 28.7, 60.2 (NCH3), 61.0 (NCH2), 92.0
(β-CH), 102.8 (CaCαCβ), 123.6 (m-Ar-C), 125.8 (p-Ar-C), 135.0
(CaCαCβ), 142.8 (o-Ar-C), 146.8 (i-Ar-C), 164.1 (NCMe). IR
(KBr): 3050, 3019, 2959, 2924, 2864, 2815, 1775, 2027, 1542, 1516,
1459, 1435, 1399, 1364, 1314, 1267, 1251, 1225, 1170, 1100, 1021,
[LMgCCCH2OMe]2 (6). Yield: 250 mg, 0.49 mmol, 49%. 1H NMR
3
i
(d8-toluene, 300 MHz, 298 K): δ 0.47 (d, 6H, J = 6.6 Hz, Pr-CH3),
1.15 (d, 6H, 3J = 6.6 Hz, iPr-CH3), 1.18 (d, 6H, 3J = 6.6 Hz, iPr-CH3),
3
i
1.42 (s, 6H, NCCH3), 1.44 (d, 6H, J = 6.6 Hz, Pr-CH3), 3.00 (sept,
2H, 3J = 6.6 Hz, iPr-CH), 3.16 (s, 3H, OCH3), 3.35 (sept, 2H, 3J = 6.6
Hz, iPr-CH), 3.94 (s, 2H, OCH2), 4.60 (s, 1H, β-CH), 6.97−7.15 (m,
6H, Ar-H). 13C{1H} NMR (d8-toluene, 77.5 MHz, 298 K): δ 24.2,
24.3, 24.4, 24.9, 25.9, 27.4, 29.0, 57.7 (OCH3), 60.8 (OCH2), 95.0 (β-
CH), 115.6 (MCαCβ), 120.4 (MCαCβ), 123.8 (m-Ar-C), 124.2
(m-Ar-C), 125.8 (p-Ar-C), 142.0 (o-Ar-C), 143.7 (o-Ar-C), 145.6 (i-Ar-
C), 169.5 (NCMe). IR (KBr): 3057, 3018, 2961, 2917, 2814, 2026,
1538, 1523, 1460, 1434, 1403, 1365, 1313, 1264, 1231, 1178, 1104,
1060, 1022, 928, 900, 808, 759, 759 cm−1. The product consistently
yielded unsatisfactory elemental analysis, despite NMR data showing a
single clean product. NMR spectra are provided in the Supporting
Information as corroborative evidence of purity.
930, 889, 841, 788, 758 cm−1. Anal. Calcd for C68H98Ca2N6 (Mw
=
1079.7): C, 75.64; H, 9.15; N, 7.78. Found: C, 75.62; H, 9.16; N, 7.69.
Group 2 Mediated Coupling of Terminal Acetylenes. Inside a
glovebox 20 μmol of precatalyst and 80 μmol of THF were dissolved
in 0.25 mL of d8-toluene and transferred into a J. Young tap NMR
tube. A 0.4 mmol portion of acetylene was then dissolved in 0.25 mL
of d8-toluene and added to the precatalyst solution. The resulting
reaction mixture was sealed and heated to 80−160 °C while being
1
regularly monitored by H NMR until no further conversion to the
coupled product was observed.
[MeOCH2CHCCCHCH2OMe]. 1H NMR (d8-toluene, 300
3
MHz, 298 K): δ 3.17 (s, 6H, CH3), 5.24 (d, 4H, CH2, J = 6.0 Hz),
[LMgCCCH2OPh]2 (7). Yield: 400 mg, 0.70 mmol, 70%. 1H NMR
3
6.71 (t, 2H, CH, J = 6.0 Hz). 13C{1H} NMR (d8-toluene, 75 MHz,
3
i
(d8-toluene, 300 MHz, 298 K): δ 0.46 (d, 6H, J = 6.6 Hz, Pr-CH3),
1.11 (d, 6H, 3J = 6.6 Hz, iPr-CH3), 1.15 (d, 6H, 3J = 6.6 Hz, iPr-CH3),
298K): δ 55.5 (OCH3), 90.0 (OCH2), 123.4 (HCC), 201.8 (HC
C). ESI-MS (m/z) for [C8H12O2 − Na]+: found 152.9888, calcd
152.9953.
3
i
1.32 (d, 6H, J = 6.6 Hz, Pr-CH3), 1.43 (s, 6H, NCCH3), 3.02 (sept,
2H, 3J = 6.6 Hz, iPr-CH), 3.26 (sept, 2H, 3J = 6.6 Hz, iPr-CH), 4.61 (s,
2H, OCH2), 4.65 (s, 1H, β-CH), 6.81−7.10 (m, 11H, Ar/OPh-H).
13C{1H} NMR (d8-toluene, 77.5 MHz, 298 K): δ 24.2, 24.3, 24.5, 24.9,
26.0, 27.5, 29.0, 56.0 (OCH2), 95.0 (β-CH), 114.7 (o-Ph-C), 115.1
(MCαCβ), 120.1 (MCαCβ), 121.3 (p-Ph-C) 124.0 (m-Ar-C),
124.2 (m-Ar-C), 126.0 (p-Ar-C), 129.7 (m-Ph-C), 142.1 (o-Ar-C),
143.6 (o-Ar-C), 145.3 (i-Ar-C), 158.6 (i-Ph-C), 170.0 (NCMe). IR
(KBr): 3055, 3022, 2956, 2925, 2862, 2027, 1600, 1588, 1533, 1493,
1462, 1438, 1403, 1365, 1315, 1266, 1230, 1217, 1177, 1104, 1078,
1034, 1022, 930, 849, 794, 759, 749, 690 cm−1. Anal. Calcd for
C76H96Mg2N4O2 (Mw = 1146.2): C, 79.64; H, 8.44; N, 4.89. Found: C,
79.59; H, 8.50; N, 4.86.
[PhOCH2CHCCCHCH2OPh]. Stoichiometric reactivity only.
1H NMR (C6D6, 300 MHz, 298 K): δ 5.06 (d, 4H, CH2, 3J = 5.5 Hz),
3
6.65 (t, 2H, CH, J = 5.5 Hz), 6.78−7.10 (m, 10H, Ph-H). ESI-MS
(m/z) for [C18H16O2 − Na]+: 287.1068, calcd 287.1048.
[Me2NCH2CHCCCHCH2NMe2]. Stoichiometric reactivity
only. 1H NMR (d8-toluene, 300 MHz, 298 K): δ 2.24 (s, 12H,
N(CH3)2), 5.24 (d, 4H, NCH2, 3J = 5.8 Hz), 5.92 (t, 2H, CH, 3J = 5.8
Hz).
[PhCCCHCHPh]. 90% yield, 90% Z isomer, 10% E isomer by
NMR. 1H NMR of Z isomer (d8-toluene/THF 9/1, 300 MHz, 298 K):
δ 5.76 (d, 1H, CH, 3Jcis = 11.7 Hz), 6.46 (d, 1H, CH, 3Jcis = 11.7 Hz),
3
[LMgCCCH2NMe2]2 (8). Yield: 490 mg, 0.93 mmol, 93%. 1H
NMR (d5-pyridine, 300 MHz, 298 K): δ 1.01 (d, 12H, 3J = 6.6 Hz, iPr-
CH3), 1.21 (d, 12H, 3J = 6.6 Hz, iPr-CH3), 1.08 (s, 6H, NCCH3), 2.08
7.05−7.09 (m, 4H, Ph-H), 7.17 (two overlapping d, 2H, Ph-H, J =
3
7.8, 7.2 Hz), 7.35 (two overlapping d, 2H, J = 7.8, 7.2 Hz), 7.83 (d,
3
1
2H, J = 7.5 Hz). H NMR of E isomer (d8-toluene/THF 9/1, 300
MHz, 298 K): δ 6.26 (d, 1H, CH, 3Jtrans = 16.2 Hz), 6.88 (d, 1H, CH,
3Jtrans = 16.2 Hz), 7.05−7.09 (m, 6H, m/p-Ph-H), 7.16 (d, 2H, 3J = 7.0
Hz, o-Ph-H), 7.36 (dd, 2H, 3J = 8.0 Hz, 4J = 1.5 Hz, o-Ph-H). 13C{1H}
NMR of Z isomer (d8-toluene/THF 9/1, 75 MHz, 298 K): δ 88.9
(PhCC), 96.4 (PhCC), 107.6 (PhCHCH), 124.1 (i-Ph-C),
128.6, 128.7 (p-Ph-C), 128.8, 128.9 (p-Ph-C), 129.4, 131.8, 137.2 (i-
Ph-C), 139.1 (PhCHCH). 13C{1H} NMR of E isomer (d8-toluene/
THF 9/1, 75 MHz, 298 K): δ 90.1 (PhCC), 92.8 (PhCC), 109.1
3
i
(s, 6H, NCH3), 3.09 (s, 2H, NCH2), 3.28 (sept, 2H, J = 6.6 Hz, Pr-
CH), 5.03 (s, 1H, CH), 7.20−7.23 (m, 6H, Ar-H). 13C{1H} NMR (d5-
pyridine, 77.5 MHz, 298 K): δ 24.6, 25.2, 27.0, 44.5 (NCH3), 50.8
(NCH2), 94.8 (β-CH), 104.7 (MCαCβ), 112.9 (MCαCβ), 125.7
(p-Ar-C), 129.2 (o-Ar-C), 143.2 (m-Ar-C), 145.8 (i-Ar-C), 169.3
(NCMe). IR (KBr): 3054, 3019, 2955, 2865, 2815, 2780, 2758, 2030,
1539, 1523, 1464, 1438, 1403, 1366, 1315, 1260, 1232, 1177, 1102,
1035, 1019, 929, 851, 792, 760 cm−1. The product consistently yielded
4970
dx.doi.org/10.1021/om400678d | Organometallics 2013, 32, 4961−4972