Organometallics
Article
ArCH3), unresolved (NC). 31P NMR (162.0 MHz, CDCl3): δ
(E)-N,N′-Dimesityl-N-((E)-1-((2,4,6-tri-tert-butylphenyl)-
phosphanylidene)ethyl)acetimidamide (9). Stepwise NMR-Scale
Reaction. A solution of aminophosphaalkene 7 (0.04 mmol) in DCM
(0.6 mL) was added to a NMR tube containing nitrilium triflate 1e
(0.05 mmol) at −78 °C to give a bright yellow solution, which then
was warmed to room temperature. The mixture was stirred and the
protonated bis(imino)phosphane 4e was observed by 31P NMR
spectroscopy (δ 11.3 ppm). The reaction was monitored using 31P
NMR spectroscopy, and after 120 h complete conversion toward
P,N,N-intermediate 8 was observed (δ 31P: 174.6 (s)). A solution of
triethylamine (0.07 mmol) in DCM (0.2 mL) was added to give a
yellow solution, which was stirred for 1 h, giving P,N,N-ligand 9 with
full conversion (δ 31P: 186.6 (s)). The product was not isolated.
One-Pot Synthesis. A solution of 2,4,6-tris-tert-butylphenyl-
phosphane (0.76 g, 2.7 mmol) in DCM (10 mL) was slowly added
to a solution of (N-(2,4,6-trimethylphenyl))(methyl)carbonitrilium
triflate (1e; 2.12 g, 6.9 mmol) in DCM (30 mL) at −78 °C. After
stirring the reaction mixture at this temperature for 2.5 h, triethylamine
(0.8 g, 1.2 mL, 8.2 mmol) was added over a period of 5 min. The
reaction mixture was stirred for another 2.5 h at this temperature and
then warmed to room temperature. All volatiles were evaporated, and
the product was extracted into Et2O (3 × 15 mL), after which the
filtrate was filtered over neutral alumina eluting with Et2O.
Evaporation of all volatiles gave 1.65 g (2.7 mmol, 100%) of 9 as a
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−13.7 (t, J(P,Rh) = 104.0 Hz). IR: 3016 (w), 2932 (m), 2912 (m),
2870 (m), 2824 (m), 1547 (m), 1508 (w), 1470 (m), 1427 (m), 1389
(m), 1377 (w), 1362 (w), 1327 (m), 1304 (w), 1269 (m), 1234 (w),
1211 (w), 1192 (m), 1177 (m), 1153 (w), 1138 (m), 1080 (m), 1045
(w), 1026 (w), 980 (m), 949 (m), 933 (w), 883 (w), 856 (m), 829
(m), 818 (m), 791 (w), 775 (w), 748 (m), 729 (s), 706 (s), 667 (m),
633 (w), 582 (m), 559 (w), 536 (m), 505 (m), 490 (m), 474 (m), 455
(w), 424 (s). HR ESI-MS: calcd for C36H50ClNPRh2 (M + H)
768.1474, found 768.1478. m/z (%): 312.2 (80) [M − Rh2Cl(COD)2
+ 2H]+, 522.2 (100) [M − RhCl(COD) + H]+, 768.1 (90) [M + H]+.
Reaction between N-(Mesityl)pivalimidoyl Chloride and
[CODRhCl]2. A solution of N-(mesityl)pivalimidoyl chloride (0.10 g,
0.42 mmol) in DCM (2.5 mL) was slowly added to a solution of
[RhCl(COD)]2 (0.10 g, 0.21 mmol) in DCM (2.5 mL), after which
the reaction mixture was stirred for 1 h. The brown solution was
evaporated to dryness under reduced pressure to obtain a pale brown
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wax (0.20 g; 0.42 mmol, 100%). H NMR (500.2 MHz, CDCl3): δ
6.85 (s, 2H; m-ArH), 4.23 (br s, 4H; CODH), 2.54−2.45 (m, 4H;
CODH), 2.26 (s; p-ArCH3), 2.00 (s; o-ArCH3), 1.79−1.72 (m, 4H;
CODH), 1.41 (s, 9H; C(CH3)3). 13C{1H} NMR (125.8 MHz,
CDCl3): δ 155.5 (s; NC), 143.2 (s; ipso-ArC), 133.3 (s; p-ArC),
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128.6 (s; m-ArC), 126.1 (s; o-ArC), 78.9 (d, J(C,Rh) = 13.6 Hz;
CODC), 44.0 (s; C(CH3)3), 31.0 (s; CODC), 29.7 (s; C(CH3)3), 21.0
(s; p-ArCH3), 17.7 (s; o-ArCH3). IR: 2988 (w), 2974 (w), 2934 (m),
2910 (m), 2868 (m), 2827 (m), 1697 (m), 1647 (w), 1508 (w), 1475
(m), 1466 (m), 1447 (m), 1423 (w), 1396 (w), 1364 (w), 1323 (m),
1298 (m), 1250 (m), 1227 (w), 1209 (w), 1171 (m), 1150 (m), 1078
(w), 1041 (w), 1034 (w), 993 (m), 959 (s), 935 (m), 866 (m), 851
(m), 814 (s), 773 (m), 795 (m), 735 (w), 689 (w), 609 (m), 592 (w),
579 (m), 565 (w), 538 (w), 513 (w), 486 (s), 473 (m).
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yellow solid. Mp: 131.4−134.0 °C. H NMR (500.2 MHz, CDCl3): δ
7.35 (s, 2H; m-Mes*H), 6.92 (s, 2H; (C2N)-m-MesH), 6.87 (s, 2H;
(CN)-m-MesH), 2.29 (s, 3H; (C2N)-p-MesCH3), 2.26 (s, 3H;
(CN)-p-MesCH3), 2.19 (s, 6H; (C2N)-o-MesCH3), 2.12 (s, 6H;
(CN)-o-MesCH3), 1.55 (s, 18H; o-Mes*CH3), 1.41 (s, 3H; NC-
CH3), 1.29 (s, 9H; p-Mes*CH3), 1.25 (d, 3J(H,H) = 9.8 Hz, 3H; P
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C-CH3). 13C{1H} NMR (125.8 MHz, CDCl3): δ 181.0 (d, J(C,P) =
2
65.4 Hz; PC), 153.8 (d, J(C,P) = 2.7 Hz; o-Mes*C), 153.0 (d,
2,4,6-Trimethyl-N-(1-((2,4,6-tri-tert-butylphenyl)-
phosphanylidene)ethyl)aniline (7). A solution of supermesityl
phosphane (0.70 g, 2.51 mmol) in DCM (8 mL) was added to a
solution of nitrilium triflate 1e (0.79 g, 2.55 mmol) in DCM (8 mL) at
−78 °C to give a bright yellow solution of the protonated intermediate
3J(C,P) = 3.6 Hz; NC), 148.8 (s; p-Mes*C), 144.8 (s; (CN)-ipso-
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MesC), 142.5 (d, J(C,P) = 72.7 Hz; ipso-Mes*C), 139.5 (s; (C2N)-
ipso-MesC),137.9 (s; (C2N)-p-MesC), 136.4 (s; (C2N)-o-MesC),
130.8 (s; (NC)-p-MesC), 129.5 (s; (C2N)-m-MesC), 128.5 (s;
(NC)-m-MesC), 127.4 (s; (NC)-o-MesC), 121.5 (s; m-Mes*C),
38.4 (s; o-Mes*-C(CH3)3), 35.0 (s; p-Mes*-C(CH3)3), 32.8 (d,
4J(C,P) = 9.1 Hz; o-Mes*-C(CH3)3), 31.6 (s; p-Mes*-C(CH3)3), 24.5
1
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(31P NMR: −39.96 (d, J(P,H) = 264.0 Hz), −48.25 (d, J(P,H) =
264.0 Hz)). After stirring the reaction mixture for 15 min at room
temperature, triethylamine (0.5 g, 0.7 mL, 5.1 mmol) was added to
give a yellow solution, which was stirred for 1 h. The mixture was
evaporated to give a yellow solid, which was extracted into Et2O (10
mL + 5 × 5 mL) and filtered over Celite. Crystallization from Et2O at
−20 °C afforded a mixture of Z-7 and E-7, in a ratio of 4:1 according
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(d, J(C,P) = 14.5 Hz; PC-CH3), 21.2 (s; (C2N)-p-MesCH3), 20.9
(s; (CN)-p-MesCH3), 18.7 (s; (CN)-o-MesCH3), 18.1 (s;
(C2N)-o-MesCH3), 17.0 (d, 4J(C,P) = 3.6 Hz; NC-CH3). 31P
NMR (162.0 MHz, CDCl3): δ 188.9. IR: 2949 (m), 2910 (m), 2862
(w), 1649 (s), 1609 (w), 1593 (w), 1477 (m), 1460 (w), 1408 (w),
1389 (m), 1367 (m), 1360 (m), 1340 (m), 1300 (m), 1273 (s), 1240
(m), 1225 (s), 1194 (m), 1184 (m), 1142 (w), 1128 (m), 1024 (w),
1011 (m), 933 (w), 926 (w), 904 (w), 876 (m), 851 (s), 800 (w), 773
(m), 758 (m), 723 (w), 662 (w), 648 (w), 615 (w), 586 (m), 579 (m),
567 (m), 513 (w), 474 (w). HR ESI-MS: calcd for C40H58N2P (M +
H) 597.4332, found 597.4302. m/z (%): 351.2 (100) [M − Mes*]+,
597.4 (27) [M + H]+.
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to H NMR spectroscopy, as a yellow solid (0.63 g, 1.4 mmol, 57%).
Mp: 106 °C. 1H NMR (250.1 MHz, CDCl3, Z-7): δ 7.39 (d, 4J(H,P) =
1.3 Hz, 2H; m-Mes*H), 6.76 (s, 2H; m-MesH), 4.71 (s, 1H; NH),
2.20 (s, 3H; p-MesCH3), 1.97 (s, 6H; o-MesCH3), 1.76 (d, 3J(H,P) =
21.0 Hz, 3H; PC−CH3), 1.63 (d, 5J(H,P) = 0.8 Hz, 18H; o-
Mes*C(CH3)3), 1.28 (s, 9H; p-Mes*C(CH3)3). 1H NMR (250.1
MHz, CDCl3, E-7): δ 7.40 (s, 2H; m-Mes*H), 6.94 (s, 2H; m-MesH),
5.45 (s, 1H; NH), 2.33 (s, 6H; o-MesCH3), 2.30 (s, 3H; p-MesCH3),
1.54 (s, 18H; o-Mes*C(CH3)3), 1.32 (s, 9H; p-Mes*C(CH3)3), P
C−CH3 is unresolved. 13C{1H} NMR (100.6 MHz, CDCl3, Z-7):
179.5 (d, 1J(C,P) = 65.1 Hz; CP), 156.2 (s; o-Mes*C), 149.1 (s; p-
Mes*C), 136.1 (s; o-MesC), 136.0 (d, 1J(C,P) = 46.1 Hz; ipso-
Mes*C), 136.0 (s; ipso-MesC), 136.0 (s; p-MesC), 129.1 (s; m-MesC),
121.5 (s; m-Mes*C), 38.6 (s; o-Mes*C(CH3)3), 33.3 (d, 4J(C,P) = 8.1
Hz; o-Mes*C(CH3)3), 31.5 (s; p-Mes*C(CH3)3), 21.3 (s; PC-
CH3), 20.8 (s; o-MesCH3), 19.5 (s; p-MesCH3), p-Mes*C(CH3)3 is
(E)-N,N′-Dimesityl-N-((E)-1-((2,4,6-tri-tert-butylphenyl)-
phosphanylidene)ethyl)acetimidamide Gold(I) Chloride Com-
plex (10). 9 (55 mg, 0.092 mmol) and dimethylsulfide gold(I)
chloride (22 mg, 0.074 mmol) were dissolved in DCM (4 mL) and
stirred for 30 min at room temperature. Subsequently, all volatiles
were removed in vacuo, and the remaining yellow solid was washed
with pentane to obtain 20 mg (0.024 mmol, 32%) of 10 as a pale
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yellow solid. Mp: 93.1 °C (dec). H NMR (500.2 MHz, CDCl3): δ
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7.51 (d, J(H,P) = 3.5 Hz, 2H; m-Mes*H), 7.11 (s, 2H; (C2N)-m-
3
unresolved. 31P NMR (101.3 MHz, CDCl3): δ 65.82 (q, J(P,H) =
MesH), 6.82 (s, 2H; (CN)-m-MesH), 2.43 (s, 3H; (C2N)-p-
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20.3 Hz; Z-7), 98.10 (q, J(P,H) = 9.6 Hz; E-7). IR: 2953 (m), 2907
MesCH3), 2.37 (s, 6H; (C2N)-o-MesCH3), 2.23 (s; (CN)-p-
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(w), 2866 (w), 1582 (w), 1479 (m), 1391 (w), 1366 (m), 1358 (m),
1325 (m), 1259 (s), 1217 (m), 1204 (w), 1173 (w), 1150 (m), 1126
(m), 1094 (m), 1028 (s), 970 (w), 928 (w), 903 (w), 878 (m), 862
(m), 802 (s), 609 (w), 596 (w), 579 (w), 542 (w), 517 (m), 494 (w),
459 (m). HR ESI-MS: calcd for C40H58N2P (M + Mes-NC-Me):
597.4332, found 597.4342. m/z (%): 160.1 (12) [1e − O3SCF3]+
351.2 (44) [M + Mes-NC-Me − Mes*]+, 438.3 (<1) [M + H]+,
597.4 (100) [M + Mes-NC-Me]+.
MesCH3), 2.02 (s, 6H; (CN)-o-MesCH3), 1.99 (d, J(H,P) = 23.3
Hz, 3H; PC−CH3), 1.65 (s, 18H; o-Mes*C(CH3)3), 1.39 (s; N
C−CH3), 1.31 (s, 9H; p-Mes*C(CH3)3). 13C{1H} NMR (125.8 MHz,
2
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CDCl3): δ 177.2 (d, J(C,P) = 80.8 Hz; PC), 156.8 (d, J(C,P) =
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39.1 Hz; o-Mes*C), 154.7 (d, J(C,P) = 4.5 Hz; NC), 153.5 (d,
4J(C,P) = 2.3 Hz; p-Mes*C), 144.6 (s; (CN)-ipso-MesC), 140.5 (s;
(C2N)-p-MesC), 137.5 (d, 3J(C,P) = 6.4 Hz; (C2N)-ipso-MesC), 135.7
4
(d, J(C,P) = 2.7 Hz; (C2N)-o-MesC), 132.0 (s; (CN)-p-MesC),
G
Organometallics XXXX, XXX, XXX−XXX