798 J. Am. Chem. Soc., Vol. 121, No. 4, 1999
Kingsbury et al.
1
After the mixture was stirred at room temperature for 30 min, 400 MHz
1H NMR analysis revealed a 1:1 mixture of metal complexes 11 and
12 by integration of the corresponding carbene proton (HR) signals.
The reaction mixture was concentrated under reduced pressure and
loaded onto a short column of silica. Elution with CH2Cl2 afforded 12
as a green-brown solid residue. In analogy to the purification of complex
13, the column was washed with a 10:1 CH2Cl2:CH3OH solution to
determine if any product had adhered to the silica gel during the flash.
Yield ) 13.6 mg, 0.0238 mmol, 33%. IR (KBr): 2926 (s), 2850 (s),
1592 (w), 1574 (w), 1476 (m), 1459 (m), 1446 (m), 1294 (w), 1239
(w), 1226 (w), 1111 (w), 1011 (m), 849 (w), 746 (m), 731 (w), 515
(w). 1H NMR (400 MHz, CDCl3): δ 17.36 (d, JPH ) 4.7 Hz, 1H, Rud
CH), 7.67-7.60 (m, 2H, aromatic H), 7.14-7.09 (m, 2H, aromatic
H), 4.31 (s, 3H, OCH3), 2.36-0.84 (m, 33H, P(C6H11)3). 13C NMR
(100 MHz, CDCl3): δ 277.70, 155.01, 143.36, 129.99, 123.71, 122.26,
112.01, 58.16, 35.33 (d, JPC ) 24.4 Hz), 29.73, 27.45, (d, JPC ) 10.8
Hz), 25.94. 31P NMR (162 MHz, CDCl3): δ 61.17 (s, P(C6H11)3). Anal.
Calcd for C26H41Cl2OPRu: C, 54.54; H, 7.22. Found: C, 54.29; H,
7.06.
was detectable (400 MHz H NMR analysis) in the methanolic rinse
fraction. Evaporation of the solvent provided the product 17 as an
analytically pure brick red solid residue (750 mg, 1.29 mmol, 90%).
This complex was obtained as a microcrystalline red powder (mp 194-
196 °C dec) by dissolving the purified residue in 5 mL of CH2Cl2 and
precipitating with pentane (150 mL). IR (KBr): 3056 (w), 2980 (w),
2924 (w), 1587 (m), 1474 (m), 1434 (s), 1114 (m), 1096 (s), 928 (m),
1
694 (s), 538 (s). H NMR (400 MHz, CDCl3): δ 16.76 (d, JPH ) 6.4
Hz, 1H, RudCH), 7.65-7.53 (m, 9H, P(C6H5)3), 7.52-7.47 (m, 2H,
aromatic H), 7.46-7.39 (m, 6H, P(C6H5)3), 7.20 (d, J ) 8.3 Hz, 1H,
aromatic H), 7.11 (dd, J ) 7.8, 7.3 Hz, 1H, aromatic H), 5.43 (m, 1H,
OCH(CH3)2), 1.89 (d, J ) 6.4 Hz, 6H, OCH(CH3)2). 13C NMR (100
MHz, CDCl3): δ 278.16, 154.59, 143.27, 134.12 (d, JPC ) 9.8 Hz),
131.67, 131.13, 130.78 (d, JPC ) 2.0 Hz), 130.16, 128.58 (d, JPC
)
10.7 Hz), 122.80 (d, JPC ) 16.6 Hz), 113.56, 76.35, 21.86. 31P NMR
(162 MHz, CDCl3): δ 61.11 (s, PPh3). HRMS Calcd for C28H27Cl2-
OPRu: 582.0220. Found: 582.0220. Anal. Calcd for C28H27Cl2OPRu:
C, 57.74; H, 4.67. Found: C, 57.50; H, 4.72.
Cl2Ru(dCH-o-O-i-PrC6H4)PCy3 (8). Starting with 17 (375 mg,
0.644 mmol) and tricyclohexylphosphine (360 mg, 1.28 mmol, 2.0
equiv) in CH2Cl2 (6.5 mL) at -78 °C, 8 was obtained in analogy to 12
as a dark brown solid residue after silica gel column chromatography
(CH2Cl2) (292 mg, 0.486 mmol, 75%). Chromatography was monitored
visually, as the product was observed to rapidly elute as a dark brown
band. As in the purification of 13, the chromatography procedure was
repeated if necessary until no product was detectable in the methanolic
rinse fraction (400 MHz 1H NMR analysis). All product fractions were
then pooled, concentrated, and chromatographed once with 3:1 hexane:
CH2Cl2. Large needlelike crystals (mp ) 200-201 °C) of 8 were
obtained by dissolving the solid residue in pentane at 30-35 °C and
slowly cooling to 22 °C. The crystals were cooled to -20 °C for 24 h
to complete the recrystallization. All attempts to recrystallize complex
8 prior to purification by chromatography were unsuccessful. IR
(KBr): 2932 (s), 2849 (s), 1589 (m), 1473 (m), 1450 (m), 1375 (w),
2-Isopropoxybenzaldehyde p-Toluenesulfonhydrazone. A mixture
of sodium metal (1.16 g, 50.4 mmol, 2.1 equiv) in ethanol (50 mL)
was charged dropwise with 2.60 mL (24.4 mmol) of salicylaldehyde
in a 100 mL round-bottom flask; the sodium salt of the phenoxide ion
quickly precipitated as a yellow solid. The reaction flask was
subsequently charged with 2-iodopropane (5.0 mL, 50 mmol, 2.1 equiv)
and equipped with a reflux condenser. The mixture was heated at reflux
for 5-6 h, forming a clear, gold-colored solution; at this time, the
reaction was quenched with 10 mL of a saturated solution of sodium
chloride. Basic (1 M NaOH) aqueous extraction with methylene chloride
and removal of volatiles in vacuo afforded a yellow oil that was purified
by silica gel chromatography to yield 3.20 g (19.5 mmol, 80%) of a
light yellow oil. IR (NaCl): 2979 (m), 2935 (w), 2860 (w), 2760 (w),
1686 (s), 1600 (s), 1243 (s). 1H NMR (400 MHz, CDCl3): δ 10.50 (d,
J ) 0.9 Hz, 1H, HCdO), 7.83 (dd, J ) 7.9, 1.8 Hz, 1H, aromatic H),
7.51 (ddd, J ) 8.4, 7.3, 1.8 Hz, 1H, aromatic H), 6.99 (m, 2H, aromatic
H), 4.68 (septet, J ) 6.0 Hz, 1H, (CH3)2CHO), 1.40 (d, J ) 6.0 Hz,
6H, (CH3)2CHO). 13C NMR (100 MHz, CDCl3): δ 190.14, 160.57,
135.70, 128.24, 125.69, 120.35, 113.96, 71.05, 21.94. HRMS Calcd
for C10H12O2: 164.0837. Found: 164.0840. Anal. Calcd for C10H12O2:
C, 73.15; H, 7.37. Found: C, 72.90; H, 7.31. 2-Isopropoxybenzaldehyde
(890 mg, 5.42 mmol, 1.1 equiv) and p-toluenesulfonyl hydrazide (900
mg, 4.83 mmol) were used to prepare this hydrazone in analogy to
2-methoxybenzaldehyde p-toluenesulfonhydrazone as a bright white
crystalline solid (1.58 g, 4.75 mmol, 98%). If the product failed to
crash out of the reaction mixture upon dissolution of the reactants, seed
crystals of authentic product were added to induce precipitation. IR
(NaCl): 3200 (b), 2980 (w), 2930 (w), 1598 (m), 1484 (m), 1457 (m),
1363 (s), 1325 (m), 1295 (w), 1248 (w), 1167 (s), 1118 (w), 1094 (w),
1
1296 (m), 1216 (m), 1114 (s), 1098 (m), 934 (m), 744 (s). H NMR
(400 MHz, CDCl3): δ 17.44 (d, JPH ) 4.4 Hz, 1H, RudCH), 7.67
(ddd, J ) 7.3, 1.5, 1.0 Hz, 1H, aromatic H), 7.61 (ddd, J ) 8.3, 7.3,
1.0 Hz, 1H, aromatic H), 7.10-7.04 (m, 2H, aromatic H), 5.28 (m,
1H, OCH(CH3)2), 2.37-1.20 (m, 33H, P(C6H11)3), 1.80 (d, J ) 5.9
Hz, 6H, OCH(CH3)2). 13C NMR (100 MHz, CDCl3): δ 280.63, 153.15,
144.22, 129.89, 123.06, 122.71, 113.52, 75.52, 35.41 (d, JPC ) 10.7
Hz), 29.85, 27.49 (d, JPC ) 24.4 Hz), 26.01, 21.81. 31P NMR (162
MHz, CDCl3): δ 59.17 (s, PCy3). HRMS Calcd for C28H45Cl2O3PRu:
597.1644 (99Ru isotope peak). Found: 597.1648. Anal. Calcd for C28H45-
Cl2O3PRu: C, 55.99; H, 7.55. Found: C, 56.27; H, 7.75.
One-Pot Synthesis of Cl2Ru(dCH-o-O-i-PrC6H4)PCy3 (8). A
solution of RuCl2(PPh3)3 (825 g, 0.860 mmol) in CH2Cl2 (10.0 mL)
was treated at -78 °C with an ice-cold solution of 16 (300 mg, 1.70
mmol, 2.0 equiv) in pentane (5 mL). The resulting mixture was stirred
for 5-10 min at -78 °C, at which point a solution of PCy3 (490 mg,
1.75 mmol, 2.0 equiv) in CH2Cl2 (5 mL) was added via cannula. The
cooling bath was removed and the mixture was allowed to warm to 22
°C and stirred for 30 min. Removal of volatiles in vacuo afforded a
dark brown solid residue that was purified as above by passage through
a plug of silica gel (CH2Cl2) to afford 390 mg of the desired product
(0.649 mmol, 76%).
1
1043 (w), 947 (w), 668 (m). H NMR (400 MHz, CDCl3): δ 8.19 (s,
1H, CHdN), 7.98 (s, 1H, CdNNH), 7.88 (m, 2H, aromatic H), 7.82
(m, 1H, aromatic CH), 7.31-7.26 (m, 3H, aromatic H), 6.90 (dd, J )
7.5, 7.7 Hz, 1H, aromatic H), 6.85 (d, J ) 8.4 Hz, 1H, aromatic H),
4.53 (septet, J ) 6.0 Hz, 1H, OCH(CH3)2), 2.39 (s, 3H, ArCH3), 1.29
(d, J ) 6.2 Hz, OCH(CH3)2). 13C NMR (100 MHz, CDCl3): δ 156.51,
144.65, 144.14, 135.47, 131.73, 129.66, 128.00, 126.83, 122.55, 120.63,
113.58, 70.82, 21.89, 21.45. HRMS Calcd for C17H20N2O3S: 332.1195.
Found: 332.1196. Anal. Calcd for C17H20N2O3S: C, 61.42; H, 6.06;
N, 8.43. Found: C, 61.23; H, 6.11; N, 8.54.
Cl2Ru(dCH-o-OMeC10H6)PCy3 (9). A 5 mL round-bottom flask
was charged with Cl2Ru(dCHPh)(PCy3)2 (85.0 mg, 0.103 mmol, 1.1
equiv), 2-methoxy-3-ethenylnaphthalene (17.0 mg, 0.0923 mmol), and
CH2Cl2 (1 mL). The resulting mixture was stirred for 22 h at 22 °C,
after which the volatiles were removed in vacuo. The resulting solid
residue was purified by silica gel chromatography to afford 9 as a brown
solid (30.0 mg, 0.0482 mmol, 52%), which was then dissolved in
pentane at 22 °C and recrystallized at -20 °C (mp ) 195-196 °C
Cl2Ru(dCH-o-O-i-PrC6H4)PPh3 (17). Starting from 2-isopropoxy-
benzaldehyde tosylhydrazone (1.57 g, 4.72 mmol) and 1,1′,3,3′-
tetramethylguanidine (6.5 mL, 52 mmol, 11 equiv), a procedure identical
to that used for the synthesis of 2-methoxydiazomethane was employed
to obtain the diazo precursor 16; the diazo compound was isolated as
a red oil (503 mg, 2.85 mmol, 60%). An ice-cold pentane solution of
16 (503 mg, 2.85 mmol, 2.0 equiv) was transferred by cannula directly
into a CH2Cl2 solution of RuCl2(PPh3)3 (1.37 g, 1.43 mmol) at -78
°C. A color change from purple-brown to deep red ensued along with
a spontaneous evolution of N2. After 5 min the solvent was removed
in vacuo and the resulting red-brown residue was purified by silica gel
flash chromatography (CH2Cl2). As in the purification of 13, the
chromatography protocol was repeated if necessary until no product
1
(dec). H NMR (400 MHz, CDCl3): δ 17.52 (d, JPH ) 4.4 Hz, 1H,
RudCH), 8.19 (s, 1H, aromatic H), 8.03 (d, J ) 8.4 Hz, 1H, aromatic
H), 7.72 (d, J ) 7.6 Hz, 1H, aromatic H), 7.65 (dd, J ) 8.0, 6.8 Hz,
1H, aromatic H), 7.39 (ddd, J ) 7.6, 6.8, 0.8 Hz, 1H, aromatic CH),
7.33 (s, 1H, aromatic H), 4.39 (s, 3H, OCH3), 2.38-0.86 (m, 33H,
P(C6H11)3). 13C NMR (100 MHz, CDCl3): δ 269.20, 152.71, 144.04,
133.81, 130.74, 129.29, 128.05, 127.52, 125.99, 120.19, 107.52, 58.31,