Cobaloxime-Substituted Carbonyl Compounds
Organometallics, Vol. 19, No. 14, 2000 2739
product was extracted with (4 × 100 mL), dried with MgSO4,
and concentrated under pressure. The resulting sticky solid
was triturated with 1:1 pentane/EtO2 to yield a dark brown-
orange solid (1.864 g, 3.77 mmol, 94%); decomposes at 99-
fraction from the orange band proved to be the dienyl complex
and needed no further purification.
(1,3-(E)- a n d -(Z)-Bu ta d ien e-4-yl)(p yr id in e)bis(d im eth -
ylglyoxim a to)coba lt(III) (45a ). (Method A) Hydroxy silane
44a (0.097 g, 0.19 mmol) was dissolved in THF (30 mL).
Potassium hydride (0.063 g, 0.95 mmol) was added, and the
procedure outlined in the above section was followed. The
dienyl complex was obtained as a yellow solid (44a ) (0.037 g,
0.088 mmol, 46% yield) with varying E:Z ratios. Following
method B, column chromatography of hydroxy silane 44a (1.00
g, 1.96 mmol) on silica gel also provided the product (Z only)
(45a ) (0.56 g, 1.33 mmol, 67% yield); decomposes at 170 °C.
1
101° C. H NMR (CDCl3): 8.65 (d, J ) 5.2 Hz, 2H), 8.52 (d, J
) 14.3 Hz, 1H), 7.80 (m, 3H), 7.57-7.46 (m, 1H), 7.40 (m, 4H),
6.92 (d, J ) 14.3 Hz, 1H), 2.13 (s, 12H). 13C NMR (CDCl3):
186.53, 151.06, 150.52, 138.87, 138.54, 133.97, 132.41, 129.44,
128.61, 126.00, 12.84. IR (NaCl): 3588, 3567, 3510, 3447, 3060,
1652, 1542, 1237, 1013 cm-1. Anal. Calcd for C22H26CoN5O4:
C, 52.91; H, 5.24. Found: C, 53.36; H, 5.08.
Gen er a l P r oced u r e for th e Syn th esis of Coba loxim e
r-Hyd r oxy Sila n e Com p lexes. The unsaturated acyl com-
plex was dissolved in THF (25 mL). The reaction mixture was
cooled to 0 °C in an ice bath. The (trimethylsilyl methyl)lithium
or Grignard reagent (3.5 equiv) was slowly added by syringe.
The solution was allowed to gradually warm to 25 °C over-
night. The reaction mixture was then poured into an ice/
saturated NH4Cl solution (150 mL). The product was extracted
with EtOAc (3 × 75 mL), dried with MgSO4, and then
concentrated under reduced pressure to yield an orange-brown
oil. Attempted chromatographic purification of these com-
pounds yielded the respective dienes; therefore inadequate
HRMS and elemental analyses were obtained.
IR (NaCl): 2948, 2924, 1556, 1446, 1294 cm-1 1H NMR
.
(CDCl3): E isomer, 18.41 (bs, 2H), 8.62 (d, J ) 6.4 Hz, 2H),
7.73 (t, J ) 7.6 Hz, 1H), 7.33 (t, J ) 6.3 Hz, 2H), 6.83 (m, 1H),
6.48 (d, J ) 13.8 Hz, 1H), 5.90 (dd, J ) 13.8 Hz, 3.9 Hz, 1H),
4.81 (dd, J ) 16.8, 0.93 Hz, 1H), 4.58 (dd, J ) 9.6, 0.93 Hz,
1H), 2.10 (s, 12H); Z isomer, 18.41 (bs, 2H), 8.67 (d, J ) 4.9
Hz, 2H), 7.59 (t, J ) 7.6 Hz, 1H), 7.33 (t, J ) 6.2 Hz, 2H), 6.83
(m, 1H), 6.25 (d, J ) 7.9 Hz, 1H), 5.75 (t, J ) 7.9 Hz, 1H),
5.06 (dd, J ) 10.0, 1.1 Hz, 1H), 4.96 (dd, J ) 16.4, 1.1 Hz,
1H), 2.09 (s, 12H). 13C NMR (CDCl3): 150.07, 149.85, 149.77,
149.57, 137.75, 135.67, 125.29, 116.34, 12.10. HRMS FAB (m/
z): calcd for C17H25O4N5Co (MH)+, 422.1239; found 422.1250.
Anal. Calcd for C17H24O4N5Co: C, 48.46; H, 5.74. Found: C,
47.97; H, 6.31.
(2-Meth yl-1,3(E)- a n d -(Z)-bu ta d ien e-4-yl)(p yr id in e)-
bis(d im eth ylglyoxim a to)coba lt(III) (45b). (Method A) Hy-
droxy silane 44b (0.151 g, 0.29 mmol) was dissolved in THF
(30 mL). Potassium hydride (0.094 g, 1.4 mmol) was added,
and the procedure outlined in the above section was followed.
The dienyl complex was obtained as an orange solid (45b) (0.60
g, 1.38 mmol, 48% yield) with varying E:Z ratios. Following
method B, column chromatography of hydroxy silane 44b
(0.244 g, 0.46 mmol) on silica gel also provided the product (Z
only) (45b) (0.102 g, 0.234 mmol, 51% yield); mp 159-162 °C.
IR (NaCl): 3413, 2948, 2872, 1556, 1438, 1227 cm-1. 1H NMR
(CDCl3): E isomer, 8.56 (d, J ) 6.5 Hz, 2H), 7.69 (t, J ) 7.5
Hz, 1H), 7.28 (t, J ) 7.4 Hz, 2H), 6.40 (d, J ) 14.1 Hz, 1H),
5.92 (d, J ) 14.1 Hz, 1H), 4.61 (d, J ) 1.3 Hz, 1H), 4.52 (d, J
) 1.3 Hz, 1H), 2.06 (s, 12H), 1.68 (s, 3H); Z isomer, 8.53 (d, J
) 6.4 Hz, 2H), 7.69 (t, J ) 7.6 Hz, 1H), 7.28 (t, J ) 7.4 Hz,
2H), 5.71 (d, J ) 8.6 Hz, 1H), 5.32 (d, J ) 8.6 Hz, 1H), 4.58 (d,
J ) 1.3 Hz, 1H), 4.45 (d, J ) 1.3 Hz, 1H), 2.08 (s, 12H), 1.65
(s, 3H). 13C NMR (CDCl3): 150.07, 149.89, 149.62, 149.55,
137.60, 125.27, 125.14, 110.66, 23.71, 12.22. HRMS FAB
(m/z): calcd for C18H27O4N5Co (MH)+, 436.1395; found 436.1408.
Anal. Calcd for C18H26O4N5Co: C, 49.66; H, 6.02. Found: C,
49.18; H, 6.22.
(2-Hydr oxyl-1-tr im eth ylsilyl-3(Z)-bu ten -4-yl)(pyr idin e)-
b is(d im et h ylglyoxim a t o)cob a lt (III) (44a ). Unsaturated
acyl complex 35 (0.100 g, 0.24 mmol) was dissolved in THF
(25 mL). The R-hydroxy silane complex 44a was obtained as
an orange-brown oil (0.111 g, 0.21 mmol, 91% yield) after
following the procedure outlined above. IR (NaCl): 3426, 2954,
1302 cm-1. 1H NMR (CDCl3): 8.61 (d, J ) 6.4 Hz, 2H), 7.75 (t,
J ) 7.7 Hz, 1H), 7.33 (t, J ) 7.4 Hz, 2H), 6.02 (d, J ) 7.3 Hz,
1H), 5.12 (t, J ) 7.4 Hz, 1H), 4.42 (q, J ) 7.4 Hz, 1H), 2.07 (s,
12H), 0.90 (d, J ) 7.4 Hz, 2H), -0.07 (s, 9H). 13C NMR
(CDCl3): 150.85, 150.24, 149.73, 144.47, 137.83, 125.33, 65.06,
26.92, 12.04, -0.71.
(2-H yd r oxyl-2-m et h yl-1-t r im et h ylsilyl-3(Z)-b u t en -4-
yl)(p yr id in e)bis(d im et h ylglyoxim a t o)coba lt (III) (44b).
Unsaturated acyl complex 33a (0.100 g, 0.23 mmol) was
dissolved in THF (25 mL). The hydroxy silane complex was
obtained as an orange-brown oil (44b) (0.106 g, 0.201 mmol,
88% yield) after following the procedure outlined above. IR
(NaCl): 3379, 2957, 2923, 1547, 1235, 1092 cm-1 1H NMR
.
(CDCl3): 8.62 (d, J ) 6.5 Hz, 2H), 7.72 (t, J ) 7.5 Hz, 1H),
7.31 (t, J ) 7.5 Hz, 2H), 5.78 (d, J ) 8.5 Hz, 1H), 5.22 (d, J )
8.7 Hz, 1H), 2.10 (s, 12H), 2.07 (s, 3H), 1.20 (s, 2H), -0.05 (s,
9H). 13C NMR (CDCl3): 150.77, 149.66, 148.62, 137.75, 137.40,
125.08, 64.66, 33.70, 12.31, 12.08, 0.42.
(2-Hyd r oxyl-2-p h en yl-1-tr im eth ylsilyl-3(Z)-bu ten -4-yl)-
(p yr id in e)bis(d im eth ylglyoxim a to)coba lt(III) (44c). Un-
saturated acyl complex 33b (0.100 g, 0.20 mmol) was dissolved
in THF (25 mL). The hydroxy silane complex was obtained as
an orange-brown oil (44c) (0.105 g, 0.179 mmol, 89% yield).
1H NMR (CDCl3): 8.55 (d, J ) 5.7 Hz, 2H), 7.68 (t, J ) 7.3
Hz, 1H), 7.41 (t, J ) 7.7 Hz, 2H), 7.27 (t, J ) 7.0 Hz, 2H), 7.17
(t, J ) 8.0 Hz, 2H), 7.09 (d, J ) 7.5 Hz, 1H), 6.13 (d, J ) 8.8
Hz, 1H), 5.71 (d, J ) 8.8 Hz, 1H), 2.03 (s, 12H), 1.65 (s, 2H),
-0.14 (s, 9H).
Gen er a l P r oced u r e for th e Syn th esis of 1-Coba loxim e
Bu ta d ien e Com p lexes. (Method A) By following a method
similar to the original Peterson olefination procedure,18 the
hydroxy silane complex was dissolved in THF (30 mL).
Potassium hydride (35% dispersion in mineral oil) (5.0 equiv)
was then added as a THF slurry. The reaction mixture was
refluxed for 4 h. Upon cooling, the solution was poured into
an ice/saturated NH4Cl solution (150 mL) containing pyridine
(0.50 mL). The product was extracted with EtOAc (3 × 75 mL),
dried with MgSO4, and then concentrated under reduced
pressure to yield an orange/yellow solid. (Method B) The crude
hydroxy silane was chromatographed on silica gel (EtOAc). The
(2-P h en yl-1,3(Z)-bu ta d ien e-4-yl)(p yr id in e)bis(d im eth -
ylglyoxim a to)coba lt(III) (45c). Following method B, column
chromatography of hydroxy silane 44c (0.105 g, 0.179 mmol)
on silica gel also provided the product (Z only) (45c) (0.060 g,
0.12 mmol, 67% yield); decomposes at 147 °C. IR (NaCl): 2948,
2923, 1556, 1227 cm-1. 1H NMR (CDCl3): Z isomer, 18.29 (bs,
2H), 8.55 (d, J ) 5.7 Hz, 2H), 7.68 (t, J ) 7.3 Hz, 1H), 7.41 (t,
J ) 7.7 Hz, 2H), 7.27 (t, J ) 7.0 Hz, 2H), 7.17 (t, J ) 8.0 Hz,
2H), 7.09 (d, J ) 7.5 Hz, 1H), 5.95 (d, J ) 9.0 Hz, 1H), 5.89 (d,
J ) 9.0 Hz, 1H), 5.54 (s, 1H), 5.07 (s, 1H), 2.03 (s, 12H). 13C
NMR (CDCl3): 150.12, 149.73, 142.08, 139.03, 138.33, 137.59,
127.94, 126.96, 125.82, 125.14, 111.80, 11.83. HRMS FAB
(m/z): calcd for C23H29O4N5Co (MH)+, 498.1552; found 498.1476.
(2-Meth yl-1,3(E)-bu ta d ien e-4-yl)(p yr id in e)bis(d im eth -
ylglyoxim a to)coba lt(III) (46). Acyl complex 43b (0.200 g,
0.458 mmol) was dissolved in THF (30 mL). The Petasis
reagent [(tBuCp)2TiMe2] (Strem Chemical) (1.5 equiv) was
added, and the reaction mixture was degassed for 10 min. The
reaction was refluxed overnight. After cooling to room tem-
perature, the reaction mixture was then poured into ice water
containing pyridine (0.75 mL). The product was extracted with
EtOAc (3 × 75 mL), dried with MgSO4, and concentrated under