Preparation of cobaloxime-substituted unsaturated carbonyl compounds and their subsequent conversion into 1-cobaloxime-substituted 1, 3-dienyl complexes

Article abstract of DOI:10.1021/om000230m

Reduced cobaloxime (cobaloxime = [(pyridine)(dimethylglyoxime)₂cobalt]) compounds react with a variety of oxygen-substituted allenic and propargyl electrophiles to produce cobaloxime-substituted α, β- or β, γ-unsaturated ketones and aldehydes. Two of the new unsaturated acyl complexes prepared have been characterized by X-ray crystallography. Several of the α, β-unsaturated acyl complexes were subsequently converted into 1-co-baloxime-1, 3-dienyl complexes using Peterson or Petasis olefinations. One of these new dienyl complexes has also been characterized by X-ray crystallography.

Full text of DOI:10.1021/om000230m

2730
Organometallics 2000, 19, 2730-2740
P r ep a r a tion of Coba loxim e-Su bstitu ted Un sa tu r a ted
Ca r bon yl Com p ou n d s a n d Th eir Su bsequ en t Con ver sion
in to 1-Coba loxim e-Su bstitu ted 1,3-Dien yl Com p lexes
Brittany L. Hayes, Torrey A. Adams, Kerry A. Pickin, Cynthia S. Day,# and
Mark E. Welker*
Department of Chemistry, Wake Forest University, P.O. Box 7486,
Winston-Salem, North Carolina 27109
Received March 16, 2000
Reduced cobaloxime (cobaloxime ) [(pyridine)(dimethylglyoxime)2cobalt]) compounds react
with a variety of oxygen-substituted allenic and propargyl electrophiles to produce co-
baloxime-substituted R,â- or â,γ-unsaturated ketones and aldehydes. Two of the new
unsaturated acyl complexes prepared have been characterized by X-ray crystallography.
Several of the R,â-unsaturated acyl complexes were subsequently converted into 1-co-
baloxime-1,3-dienyl complexes using Peterson or Petasis olefinations. One of these new dienyl
complexes has also been characterized by X-ray crystallography.
In tr od u ction
we found that we could not effect Diels-Alder reactions
of dienyl complexes that were 2,3-disubstituted (6).2b To
circumvent this synthetic limitation, we began to look
for methods of preparing 1-cobaloxime-substituted 1,3-
dienes. Hydrocobaltation of vinyl allenes (9) proved
successful but again suffers from the limitation of
requiring the synthesis of easily polymerizable vinyl
allenes (9) and only leads to 1,1-disubstituted 1,3-dienyl
complexes (10).5
Over the last 7 years, we have reported a number of
examples of transition-metal anions (1) which react with
allenic electrophiles (2) to produce products that can be
rationalized by SN2′1 and SN22 reactions of 1 with 2. We
have also reported an alternative method for the
preparation of 2-cobaloxime-substituted 1,3-dienyl com-
plexes that involves hydrocobaltation reactions of
enynes.3 The 2-transition-metal-substituted 1,3-dienes
(4)1 are extremely reactive in Diels-Alder [4 + 2]
cycloadditions,1 and the 4-transition-metal-substituted
1,2-dienes (3)2 are precursors for metal-complexed alky-
lidene cyclobutanone synthesis (5).2a,4
We have also previously shown that cobaloxime
anions (7) and hydrides (8) react with ynones (11) and
ynoates (11, R2 ) OR) to produce unsaturated acyl
complexes (12-14).6 We thought alkenation of â-co-
baloxime-substituted R,â-unsaturated acyls such as 12
and 13 might provide a general solution to the diene
synthesis problem outlined above. However, the most
synthetically useful ynone and ynoate hydrocobaltation
procedures we reported back in 19976 yielded the Z
isomer (13) as the major or exclusive product, and we
suspected dienes prepared from 13 might also have
problems attaining the s-cis conformation required for
Diels-Alder reactions.
While exploring the scope and limitations of Diels-
Alder reactions of 2-cobaloxime-substituted 1,3-dienes,
* Corresponding author. E-mail: welker@wfu.edu.
#
To whom inquiries concerning X-ray structure determinations
should be sent.
(1) For a review of our work in this area see: Welker, M. E.; Wright,
M. W.; Stokes, H. L.; Richardson, B. M.; Adams, T. A.; Smalley, T. L.;
Vaughn, S. P.; Lohr, G. J .; Liable-Sands, L.; Rheingold, A. L. Adv.
Cycloaddition 1997, 4, 149. For some other recent references to the
primary literature see: (a) Richardson, B. M.; Day, C. S.; Welker, M.
E. J . Organomet. Chem. 1999, 577, 120. (b) Adams, T. A.; Welker, M.
E.; Day, C. S. J . Org. Chem. 1998, 63, 3683. For a recent review of
cobaloxime chemistry see: Tada, M. Rev. Heteroatom Chem. 1999, 20,
97.
(2) (a) Vinson, N. A.; Day, C. S.; Welker, M. E.; Guzei, I.; Rheingold,
A. L. Organometallics 1999, 18, 1824. (b) Stokes, H. L.; Richardson,
B. M.; Wright, M. W.; Vaughn, S. M.; Welker, M. E.; Liable-Sands, L.;
Rheingold, A. L. Organometallics 1995, 14, 5520. (c) Stokes, H. L.;
Smalley, T. L.; Hunter, M. L.; Welker, M. L.; Rheingold, A. L. Inorg.
Chim. Acta 1994, 220, 305.
Here, we report reactions of cobaloximes with allenic
and alkynyl carbonyl compounds and other oxygen-
substituted allenic and alkynyl electrophiles, which in
(3) Stokes, H. L.; Welker, M. E. Organometallics 1996, 15, 2624.
(4) Benyunes, S. A.; Deeth, R. J .; Fries, A.; Green, M.; McPartlin,
M.; Nation, C. B. M. J . Chem. Soc., Dalton Trans. 1992, 3453.
(5) Lohr, G. J .; Welker, M. E. Inorg. Chim. Acta 1999, 296, 13.
(6) Adams, T. A.; Welker, M. E. Organometallics 1997, 16, 1300.
10.1021/om000230m CCC: $19.00 © 2000 American Chemical Society
Publication on Web 06/09/2000

Cobaloxime-Substituted Carbonyl Compounds
Organometallics, Vol. 19, No. 14, 2000 2731
mercially available 18 by procedures analogous to those
we have reported previously.1
several cases provide a new route to â-cobaloxime-
substituted R,â-unsaturated carbonyl compounds with
the E alkene geometry, which will most likely prove best
for subsequent Diels-Alder reactions. Several of these
cobalt-substituted acyls are then converted into 1-
cobaloxime-substituted 1,3-dienyl complexes using
carbonyl olefination reactions.
Resu lts a n d Discu ssion
(c) Rea ction s of Allen ic Electr op h iles w ith Co-
b a loxim es. Following preparation of the allenic
carbonyl compounds 16, cobaloxime anion 7 was gener-
ated at -20 °C in THF, the appropriate electrophiles
(16a or b) were added at -20 °C, and then the solutions
were allowed to warm to 25 °C and quenched with ice
water. Both substrates 16a ,b yielded â-cobaloxime-
susbstituted R,â-unsaturated compounds 26a ,b in ca.
50% yield. The isolation of these products (26) can be
rationalized via Michael reaction of the cobaloxime
anion 8 with the allenic carbonyl compounds 16 followed
by protonation (25), analogous to chemistry we have
reported previously.1
(a ) P r ep a r a tion of Oxygen a ted Allen ic Electr o-
p h iles. Allenic aldehyde 16a and allenic ketone 16b can
be prepared by Dess-Martin oxidation of the allenic
alcohols7 15 or, even more conveniently, by a Dess-
Martin oxidation/isomerization reaction of the com-
mercially available alkynols 17.8 We also easily pre-
pared propargyl ether 19 since its preparation and
isomerization to the allenic ether 20 had been previously
reported.9,10
(b) P r ep a r a tion of Oxygen a ted Alk yn yl Electr o-
p h iles. Two of the alkynones we used in this study,
3-butyn-2-one and 3-hexyn-2-one, are commerically
available, and the other two used (22a and 22b) were
easily prepared via Dess-Martin oxidation of the com-
mercially available alkynols 21a and 21b.7,8 Likewise
alkynyl tosylate 24 was easily prepared from com-
Reactions of the oxygen-substituted allene (20) with
cobaloxime proved much more complicated than we
initially anticipated. Oxygenated allene 20 reacted with
cobaloxime anion 7 in EtOH to produce R,â-unsaturated
acyl complex 27 in good yield. The isolation of this
complex (27) was unexpected since it represents a
cobaloxime addition to 20 without concomitant reduc-
tion of 20.
(7) (a) Marshall, J . A.; Yu, R. H.; Perkins, J . F. J . Org. Chem. 1995,
60, 5550. (b) Marshall, J . A.; Wang, X. J . Org. Chem. 1991, 56, 960.
(c) Marshall, J . A.; Sehon, C. A. J . Org. Chem. 1995, 60, 5966. (d)
Marshall, J . A.; Wolf, M. A.; Wallace, E. M. J . Org. Chem. 1997, 62,
367.
(8) Hashmi, A. S. K.; Ruppert, T. L.; Knofel, T.; Bats, J . W. J . Org.
Chem. 1997, 62, 7295.
(9) (a) Brandsma, L. Preparative Acetylenic Chemistry; Elsevier
Publishing Co.: New York, 1988; pp 260-261. (b) Brandsma, L.;
Verkruijsse, H. D. Synthesis of Actylenes, Allenes, and Cumulenes;
Elsevier Publishing Co.: New York, 1981; pp 65, 94-96, 171, 188, 238.
(10) (a) van Rijn, P. E.; Everhardus, R. H.; van der Ven, J .;
Brandsma, L. Recl. Trav. Chim. Pays-Bas. 1981, 100, 372. (b) Van
Boom, J . H.; Montijn, P. P.; Brandsma, L.; Arens, J . F. Recl. Trav.
Chim. 1965, 84, 31. (c) Montijn, P. P.; Schmidt, H. M.; Van Boom, J .
H.; Bos, H. J . T.; Brandsma, L.; Arens, J . F. Recl. Trav. Chim. 1965,
84, 271. (d) Mantione, R. Bull. Chim. Soc. Fr. 1969, 4514. (e) Mantione,
R. Bull. Chim. Soc. Fr. 1969, 4523.
Complex 27 was present in the crude product of the
7 + 20 reaction, prior to chromatography, so its presence

2732 Organometallics, Vol. 19, No. 14, 2000
Hayes et al.
is not due to air oxidation of SiO2.11 We could speculate
on the mechanism of formation of 27 but will not since
the focus of this work is on the preparation of R,â-
unsaturated acyls that can be converted to dienyl
complexes. Regarding this mechanism question, we can
note that switching from EtOH to the polar aprotic
solvent THF (where the predominant cobaloxime species
present should be 7 rather than 8) yielded a crude
product that by 1H NMR appeared to be a 3.5:1 mixture
of dienyl complex 29 [(CDCl3): 8.60 (d, J ) 5.0 Hz, 2H),
7.75 (t, J ) 5.0 Hz, 1H), 7.30 (t, J ) 5.0 Hz, 2H), 6.4 (d,
J ) 12.8 Hz, 1H), 5.7 (s, 1H), 5.1 (d, J ) 12.8 Hz, 1H),
3.7 (q, J ) 6.9 Hz, 2H), 3.6 (q, J ) 7.1 Hz, 2H), 2.19 (s,
12H), 1.2 (t, J ) 7.1 Hz, 3H), 1.1 (t, J ) 7.1 Hz, 3H)]
and pyr(dmg)2CoCl (28). However, attempts to purify
29 by recrystallization or chromatography on silica
resulted in enol ether hydrolysis, and the only isolable
new cobaloxime complex from this reaction proved to
be another R,â-unsaturated acyl of E alkene geometry
(30).
cobaloxime diene [4 + 2] cycloadditions, preparation of
these substrates appeared warranted.12
The two isomeric internal alkynes 36a ,b were also
subjected to similar cobaloxime addition reaction condi-
tions. Both of these internal alkynes yielded unexpected
â,γ-unsaturated cobalt acyl complexes 38 and 39. The
formation of these complexes can be rationalized by
base-induced alkyne 36-allene 37 isomerization9,10
followed by cobaloxime addition to the central sp-
hybridized carbon of the isomeric allene 37. Both of
these unusual â,γ-unsaturated acyls were characterized
by X-ray crystallography.
(d ) R ea ct ion s of Alk yn yl E lect r op h iles w it h
Coba loxim es. Alkynyl electrophile 24 is included here
because we suspected it would react with cobaloxime
anion 7 followed by hydrolysis to generate aldehyde 31,
which could also be converted into an interesting dienyl
complex. Somewhat surprisingly, from propargyl tosy-
late 24, we isolated only the SN2 product 32. We have
reported one other example of a 1,1-disubstituted allenic
tosylate which also reacted with cobaloxime anion 7 to
give a SN2 rather than SN2′ product.2b In both of these
cases where we have observed SN2 products, the carbon
R to the site of possible SN2′ attack has been disubsti-
tuted, so perhaps the two substitutents provide enough
steric hindrance to direct cobaloxime addition away from
the SN2′ position.
Figures 1 and 2 show the ORTEP drawings of
compounds 38 and 39. The bond lengths (Å) and the
bond angles (deg) for 38 are displayed in Tables 2 and
3, and the analogous data for 39 are presented in Tables
5 and 6. As Figures 1 and 2 show, the two â,γ-
unsaturated acyl cobalt complexes, 38 and 39, show
different orientations about the carbon 15-carbon 16
bond. The torsion angles (C14-C15-C16-C17) of 38
and 39 are 15° and 87°, respectively. The large torsion
angle of 39 is due to the methyl substituent that lies
cis to the remaining part of the organic R group.When
comparing the cobalt-vinyl fragment of the crystal
structures of 38 and 39 with that of the unsubstituted
2-cobaloxime-1,3-butadiene we have reported previ-
ously,13 we note that the cobalt-carbon (Co1-C15) bond
We next prepared three unsaturated acyl complexes
with Z-alkene geometry (33a , 33b, 35) by analogy with
chemistry we reported earlier.6 All these preparations
involve reactions of cobaloximes with terminal alkynes.
Dienes prepared from these acyls would be expected to
react slowly in Diels-Alder reactions unless Z to E
isomerization occurred prior to cycloaddition. Since we
had noted such thermal isomerizations previously in
(11) (a) Cohen, Z.; Keinan, E.; Mazur, Y.; Vacony, T. H. J . Org.
Chem. 1975, 40, 2141. (b) Sosnowski, J . J .; Danaher, E. B.; Murray,
R. K. J . Org. Chem. 1985, 50, 2759. (c) Ferreira, J . T. B.; Cruz, W. O.;
Vieira, P. C.; Yonashimo, M. J . Org. Chem. 1987, 52, 3698.
(12) Wright, M. W.; Welker, M. E. J . Org. Chem. 1996, 61, 133.
(13) Wright, M. W.; Smalley, T. L.; Welker, M. E.; Rheingold, A. L.
J . Am. Chem. Soc. 1994, 116, 6777.

Cobaloxime-Substituted Carbonyl Compounds
Organometallics, Vol. 19, No. 14, 2000 2733
F igu r e 1. Molecular structure of compound 38 using 50%
probability for thermal ellipsoids.
F igu r e 2. Molecular structure of compound 39 using 50%
probability for thermal ellipsoids.
F igu r e 3. (a) Molecular structure of compound 45a
(molecule 1) using 50% probability for thermal ellipsoids.
(b) Molecular structure of compound 45a (molecule 2) using
50% probability for thermal ellipsoids.
length of all three compounds is approximately 2.0 Å.
The carbon-carbon double bonds here, C14-C15 of 38
(1.34 Å) and C14-C15 of 39 (1.32 Å), are both within
experimental error of a normal CdC bond length (1.337
Å).14
Last, on acyl complex synthesis, we tried a cobaloxime
reduction/electrophile trapping procedure originally
reported by Widdowson15 for making cobaloxime com-
plexes from base and polar protic solvent-sensitive
R-halocarbonyl compounds. This method utilizes zinc to
reduce pyr(dmg)2CO(III)X to cobalt(II) in polar aprotic
solvents. In the cobaloxime generation method described
above for the preparation of 7 and 8, we reduced the
cobalt with NaBH4 in polar protic solvents and the acyl
complexes we isolate can be rationalized by classical
alkyne or allene hydrometalation. However, the Wid-
dowson cobaloxime preparation is reported to initially
generate Co(II)(Pyr)2(dmg)2 (41), which then reacts with
electrophiles by electron-transfer chemistry rather than
via cobaloxime anion (7) nucleophilic addition or co-
baloxime hydride (8) hydrometalation. We find that this
method of cobaloxime generation yields a cobalt species
that reacts with alkynyl ketones to cleanly generate
cobalt-substituted E alkenes (43) in high yield and
stereoisomeric purity. This method failed to provide a
good yield of the E unsaturated aldehyde 43a , and we
think this is partly due to the high water solubility of
that compound. For our purposes this method proved
complementary to the Schrauzer cobaloxime prepara-
(14) Mitchell, A. D., Cross, L. C., Eds. Tables of Interatomic
Distances and Angles; The Chemical Society: London, 1958.
(15) Roussi, P. F.; Widdowson, D. A. J . Chem. Soc., Perkin Trans. 1
1982, 1025.

2734 Organometallics, Vol. 19, No. 14, 2000
Hayes et al.
Ta ble 1. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
for (3-Oxo-5-h exen -5-yl)(p yr id in e)-
Ta ble 4. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
for (2-Oxo-4(E)-h exen -4-yl)(p yr id in e)-
bis(d im eth ylglyoxim a to)
bis(d im eth ylglyoxim a to) Coba lt(III) (38)
Coba lt(III)(d ich lor om eth a n e) (39)
empirical formula
fw
temperature
wavelength
C19H28CoN5O5
465.39
193(2) K
0.71073 Å
empirical formula
fw
C19H28CoN5O5(CH2Cl2)
550.32
temperature
233(2) K
cryst syst, space group
monoclinic, Pn (an alternate
description of Pc-C2s (No. 7))
a ) 8.3411(8) Å
b ) 11.774(1) Å, â ) 94.202(2)°
c ) 10.913(1) Å
1068.88(18) Å3
2, 1.446 g/cm-1
0.843 mm-1
wavelength
cryst syst, space group
unit cell dimens
0.71073 Å
monoclinic, P21/c-C5 (No. 14)
2h
unit cell dimens
a ) 9.081(1) Å
b ) 8.267(1) Å, â ) 96.01(1)°
c ) 33.225(4) Å
2480.5(6) Å3
volume
Z, calcd density
abs coeff
volume
Z, calcd density
abs coeff
4, 1.474 g/cm-1
0.947 mm-1
F(000)
488
F(000)
1144
cryst size
θ range for data collection
limiting indices
0.13 × 0.14 × 0.24 mm
crystal size
θ range for data collection
limiting indices
0.25 × 0.40 × 0.70 mm
1.73-25.05°
2.26-26.37°
-9 e h e 9, -14 e k e 12,
-12 e l e 8
5654/2649 [Rint ) 0.0523]
99.8%
-1 e h e 11, -10 e k e 1,
-41 e l e 41
6311/5081 [Rint ) 0.0226]
100.0%
no. of reflns collected/unique
completeness to θ ) 25.05
abs corr
no. of reflns collected/unique
completeness to θ ) 26.37
abs corr
empirical
empirical
max. and min. transmission
refinement method
no. of data/restraints/params
goodness-of-fit on F2
final R indices
0.5287 and 0.4370
full-matrix least-squares on F2
2649/2/290
max. and min. transmission
refinement method
no. of data/params
goodness-of-fit on F2
final R indices
0.8467 and 0.7212
full-matrix least-squares on F2
5081/333
0.933
1.039
[1874Fo > 4σ(Fo) data]
R1 ) 0.0439, wR2 ) 0.0867
R1 ) 0.0715, wR2 ) 0.0948
0.35(3)
[3866I > 2σ(Ι) data]
R1 ) 0.0417, wR2 ) 0.0946
R1 ) 0.0650, wR2 ) 0.1055
0.451 and -0.325 e/Å3
[all 2649 data]
[all 5081 data]
absolute structure (Flack)
param
largest diff peak and hole
largest diff peak and hole
0.440 and -0.274 e/Å3
Ta ble 5. Selected Bon d Len gth s (Å) of Com p ou n d
39
Ta ble 2. Selected Bon d Len gth s (Å) of Com p ou n d
38
type
length, Å
type
length, Å
Co1-N1
Co1-N2
Co1-N5
O5-C17
C15-C16
C17-C18
1.878(2)
1.881(2)
2.074(2)
1.212(4)
1.509(4)
1.504(5)
Co1-N3
Co1-N4
Co1-C15
C14-C19
C16-C17
C14-C15
1.884(2)
1.884(2)
1.992(3)
1.505(4)
1.500(4)
1.321(4)
type
length, Å
type
length, Å
Co1-N1
Co1-N2
Co1-N5
O5-C17
C16-C17
C18-C19
1.867(6)
1.887(6)
2.050(6)
1.225(10)
1.542(10)
1.502(9)
Co1-N3
Co1-N4
Co1-C15
C15-C16
C17-C18
C14-C15
1.900(6)
1.875(6)
2.008(9)
1.435(11)
1.484(11)
1.339(11)
tions. We first treated acyl complexes with Me3SiCH2-
Li to see if they could be converted to 1,3-dienes by
Peterson olefination.18 Acyl complexes 35, 33a , and 33b
Ta ble 3. Selected Bon d An gles (d eg) of Com p ou n d
38
type
angle, deg
type
angle, deg
N1-Co1-N4
N1-Co1-N2
N4-Co1-N3
N2-Co1-N3
N1-Co1-C15
N4-Co1-C15
N2-Co1-C15
N3-Co1-C15
C14-C15-Co1
O5-C17-C18
C15-C16-C17
C17-C18-C19
C15-C14-H14b
99.2(3)
81.2(3)
81.3(3)
98.3(2)
88.7(3)
90.3(3)
88.5(3)
89.5(3)
121.3(6)
120.6(8)
114.4(6)
114.4(7)
113(4)
N1-Co1-N5
N4-Co1-N5
N2-Co1-N5
N3-Co1-N5
C15-Co1-N5
N4-Co1-N2
N1-Co1-N3
C14-C15-C16
C16-C15-Co1
O5-C17-C16
C18-C17-C16
C15-C14-H14a
H14a-C14-H14b
91.3(2)
90.3(2)
91.0(2)
90.4(2)
179.4(4)
178.7(3)
178.2(3)
121.4(8)
116.8(6)
122.6(8)
116.8(8)
116(2)
were converted to R-hydroxy silanes 44a , 44b, and 44c
in high yield. Base-induced trimethylsilanol elimination
from 44a and 44b produced the desired 1,3-dienes 45a
and 45b, but the isolated yields were only moderate and
the dienes were routinely obtained as mixtures of E and
Z isomers. Acid-catalyzed Me3SiOH elimination using
silica gel proved possible and provided the dienes 45a -c
in higher isolated yield and stereochemical purity (Z).
â,γ-Unsaturated acyl complexes (38 and 39) could not
be olefinated using this procedure. Treatment of those
complexes with Me3SiCH2Li lead to a complex mixture
130(4)
tion, which provided Z alkene acyl complexes (33-35).16
We can rationalize the production of E alkenes by a
reduction/coupling scheme proceeding through inter-
mediate 42, reminiscent of the intermediates proposed
for dissolving metal reductions of alkynes.17
(e) Syn th esis of 1-Coba loxim e-1,3-bu ta d ien es.
Several of the new unsaturated acyl complexes prepared
in this study were next subjected to olefination reac-
1
1
of products, which by H NMR contained no alkene H
resonances. Those complexes (38 and 39) contain pro-
(16) (a) Schrauzer, G. N. Inorg. Synth. 1968, 11, 61. (b) Bulkowski,
J .; Cutler, A.; Dolphin, D.; Silverman, R. B. Inorg. Synth. 1980, 20,
127.
(17) House, H. O.; Kinloch, E. F. J . Org. Chem. 1974, 39, 747.
(18) Peterson, D. J . J . Org. Chem. 1968, 33, 780.

Cobaloxime-Substituted Carbonyl Compounds
Organometallics, Vol. 19, No. 14, 2000 2735
Ta ble 6. Selected Bon d An gles (d eg) of Com p ou n d
39
Ta ble 7. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
for (1,3(Z)-bu ta d ien -4-yl)(p yr id in e)-
bis(d im eth ylglyoxim a to) Coba lt(III)(ch lor ofor m )
(45a )
type
angle, deg
type
angle, deg
N1-Co1-N2
N2-Co1-N3
N1-Co1-N4
N3-Co1-N4
N1-Co1-C15
N2-Co1-C15
N3-Co1-C15
N4-Co1-C15
C14-C15-C16
C16-C15-Co1
O5-C17-C18
C16-C17-C18
81.76(10)
98.70(10)
98.48(10)
81.06(10)
89.57(11)
90.39(11)
90.33(10)
88.71(10)
121.5(3)
N1-Co1-N5
N2-Co1-N5
N3-Co1-N5
N4-Co1-N5
C15-Co1-N5
N1-Co1-N3
N2-Co1-N4
C15-C14-C19
C14-C15-Co1
O5-C17-C16
C17-C16-C15
89.55(9)
89.98(9)
90.54(9)
90.92(9)
178.99(11)
179.53(10)
179.07(10)
126.3(3)
120.7(2)
123.6(3)
118.0(3)
empirical formula
fw
temperature
wavelength
cryst syst, space group
C17H24CoN5O4(Cl3CH)
540.71
188(2) K
0.71073 Å
triclinic, P1-C11 (No. 1)
a ) 8.3124(7) Å, R ) 77.949(2)°
b ) 11.503(1) Å, â ) 73.239(2)°
c ) 13.374(1) Å, γ ) 71.805(2)°
1153.31(18) Å3
unit cell dimens
volume
Z, calcd density
abs coeff
117.78(19)
122.2(3)
114.1(3)
2, 1.557 g/cm-1
1.126 mm-1
F(000)
556
cryst size
θ range for data collection
limiting indices
0.04 × 0.12 × 0.18 mm
tons that are allylic and R to a ketone, so enolate
formation and subsequent reactions may predominate
1.60-24.10°
-7 e h e 9, -13 e k e 13,
-15 e l e 13
5792/4485 [Rint ) 0.0702]
98.8%
no. of reflns collected/unique
completeness to θ ) 24.10°
abs corr
integration
max. and min. transmission
refinement method
no. of data/restraints/params
goodness-of-fit on F2
final R indices
0.9678 and 0.8342
full-matrix least-squares on F2
4485/39/618
0.793
[2207Fo > 4σ(Fo) data]
R1 ) 0.0494, wR2 ) 0.0666
R1 ) 0.1348, wR2 ) 0.0815
[all 4485 data]
absolute structure parameter -0.01(3)
largest diff peak and hole
0.312 and -0.314 e/Å3
Ta ble 8. Selected Bon d Len gth s (Å) of Com p ou n d
45a
molecule 1
length, Å
molecule 2
type
type
length, Å
Co1-N1
Co1-N2
Co1-N3
Co1-N4
Co1-N5
Co1-C15
C15-C16
C16-C17
C17-C18
1.861(10)
1.884(9)
Co2-N21
Co2-N22
Co2-N23
Co2-N24
Co2-N25
Co2-C35
C35-C36
C36-C37
C37-C38
1.888(11)
1.904(10)
1.890(10)
1.850(10)
2.062(10)
1.942(12)
1.359(16)
1.467(17)
1.332(17)
1.876(10)
1.891(11)
2.065(10)
1.947(12)
1.314(15)
1.471(15)
1.325(16)
over olefination chemistry. Somewhat to our surprise,
(E)-R,â-unsaturated acyl complex 43b failed to react
with Me3SiCH2Li; even refluxing 43b with Me3SiCH2-
Li in THF lead to the recovery of unreacted 43b.
However, treatment of 43b with a commercially avail-
able form of Petasis’ reagent [(tBuCp)2TiMe2]19 led to
the formation of the desired (E)-1,3-dienyl complex 46
in 53% yield.
Ta ble 9. Selected Bon d An gles (d eg) of Com p ou n d
45a
molecule 1
molecule 2
type
angle, deg
type
angle, deg
N1-Co1-N2
N3-Co1-N2
N1-Co1-N4
N3-Co1-N4
N1-Co1-C15
N3-Co1-C15
N2-Co1-C15
N4-Co1-C15
N1-Co1-N5
N3-Co1-N5
N2-Co1-N5
N4-Co1-N5
N2-Co1-N4
C15-Co1-N5
N1-Co1-N3
C16-C15-Co1
C15-C16-C17
C18-C17-C16
81.0(5)
99.2(5)
98.2(5)
81.6(5)
94.6(4)
84.9(4)
83.9(4)
94.0(4)
89.6(4)
90.9(4)
91.6(4)
90.6(4)
177.7(5)
173.2(5)
179.5(5)
137.5(10)
127.1(13)
118.5(13)
N24-Co2-N21
N24-Co2-N23
N21-Co2-N22
N23-Co2-N22
N24-Co2-C35
N21-Co2-C35
N23-Co2-C35
N22-Co2-C35
N24-Co2-N25
N21-Co2-N25
N23-Co2-N25
N22-Co2-N25
C35-Co2-N25
N21-Co2-N23
N24-Co2-N22
C36-C35-Co2
C35-C36-C37
C38-C37-C36
98.2(5)
81.3(5)
80.6(5)
99.8(5)
95.8(5)
93.6(5)
85.2(4)
85.1(5)
89.0(4)
91.1(4)
90.2(4)
90.2(4)
172.8(5)
178.6(5)
178.6(5)
135.6(10)
130.3(14)
123.4(16)
The structure of dienyl complex 45a was confirmed
by X-ray crystallography. Figures 3a and 3b show the
ORTEP drawings of compound 45a . In a single crystal,
two crystallographically independent molecules were
present. For both molecules, the bond lengths (Å) are
displayed in Table 8 and the bond angles (deg) in Table
9. In comparing the crystal structure of the 1-cobaloxime
diene (45a ) with that of the 2-cobaloxime diene we
reported earlier,13 we observe similarities in the carbon-
carbon bond lengths of the diene; all lengths are within
0.05 Å of each other. The cobalt-carbon bond lengths
are similar (2.002 Å for the 2-substituted diene, 1.947
Å for 45a ). The major difference in the solid-state
structures of these two compounds is the torsion angle
(19) Petasis, N. A.; Bzowej, E. I. J . Am. Chem. Soc. 1990, 112, 6392.

2736 Organometallics, Vol. 19, No. 14, 2000
Hayes et al.
NaHCO3 (150 mL) containing Na2S2O3 (1 g). The organic layer
was saved, and this procedure was repeated four times to
remove all remaining iodine salts. The aqueous washes were
back extracted with CH2Cl2, and the combined organic layers
were dried with MgSO4. The dichloromethane was removed
by distillation. The resulting ynone was purified by Kugelrohr
distillation.
formed by the four carbon atoms of the diene. The
2-cobaloxime diene had a diene torsion angle of 54°,
while that of compound 45a is 178°. The 1-cobaloxime
(45a ) is a Z-diene that sits almost completely flat in the
s-trans conformation.
In summary, we have shown that cobaloximes react
with a variety of allenyl and alkynyl aldehydes and
ketones to cleanly produce cobaloxime-substituted un-
saturated acyl products of E or Z alkene geometry.
These cobaloxime-substituted unsaturated acyls can be
converted into 1-cobaloxime 1,3-dienyl complexes using
Peterson or Petasis olefinations. Diels-Alder reactions
of these new dienyl complexes will be reported in due
course.
1-P h en yl-2-p r op yn -1-on e (22a ). 1-Phenyl-2-propyn-1-ol
(21a ) (3.59 g, 27.0 mmol) was dissolved in dichloromethane
(100 mL). The product was obtained as a waxy, yellow solid
(22a ) (2.85 g, 21.9 mmol, 81% yield) after following the
procedure outlined above; mp 49-50 °C. This compound was
previously reported with limited characterization data and no
spectral data.21 IR (NaCl): 3227, 2096, 1684, 1454, 1260, 1007
cm-1 1H NMR (CDCl3): 8.18 (dd, J ) 7.1, 1.3 Hz, 2H), 7.65
.
(tt, J ) 7.4, 1.3 Hz, 1H), 7.51 (tt, J ) 7.8, 1.7 Hz, 2H), 3.46 (s,
1H). 13C NMR (CDCl3): 177.40, 136.19, 134.53, 129.71, 128.71,
80.79, 80.31. HRMS EI: calcd for C9H6O (M)+, 130.0419; found,
130.0423.
Exp er im en ta l Section
Gen er a l. All nuclear magnetic resonance (NMR) spectra
were obtained using a Varian VXR-200 FT NMR or a Bruker
AVANCE 300 FT NMR. All absorptions were expressed in
parts per million relative to residual protonated solvent.
Infrared (IR) spectra were obtained using a Perkin-Elmer 1620
FTIR. All elemental analyses were performed by Atlantic
Microlab, Inc. of Norcross, GA. High-resolution mass spectral
analyses were performed by the Duke University Mass Spec-
trometry Facility. Melting points were determined on a Mel-
Temp apparatus and are reported uncorrected. Tetrahydro-
furan and diethyl ether were distilled from sodium/benzo-
phenone under nitrogen immediately prior to use. Dichlo-
romethane was distilled from calcium hydride immediately
prior to use. All reactions were carried out under an atmo-
sphere of dry nitrogen. Alumina adsorption (80-200 mesh) for
column chromatography was purchased from Fisher Scientific
and deactivated with an acetone/water mixture (90:10) im-
mediately prior to use.
Cobalt chloride hexahydrate used in the preparation of acyl
and dienyl complexes was purchased from Strem Chemicals
and used as received. Dimethylglyoxime was purchased from
Fischer Scientific and recrystallized from 95% EtOH (12 mL/
g) prior to use. 3-Butyne-2-one, 3-hexyn-2-one, 3-butyn-1-ol
(17), and 4-pentyn-2-ol (21) were purchased from GFS Chemi-
cals. Propioaldehyde diethyl acetal (18) was purchased from
Lancaster. (Pyr)(dmg)2CoCl (28) was prepared according to a
literature procedure.16 Allenic electrophiles 16a and 16b were
prepared according to literature procedures.7,8 Lithium boro-
hydride in THF, sodium borohydride, and chloromethyl ethyl
ether were purchased from Aldrich Chemicals and used as
received. All reactions were performed under an atmosphere
of nitrogen unless specified otherwise.
1,1,4-Tr ieth oxy-2-bu tyn e (19). This compound was pre-
pared according to a previously reported procedure.10 Ad-
ditional spectroscopic data are included here. 1H NMR
(CDCl3): 5.30 (s, 1H), 4.20 (s, 2H), 3.75 (m, 2H), 3.55 (m, 4H),
1.20 (m, 9H). 13C NMR (CDCl3): 91.6, 82.0, 81.7, 67.0, 61.5,
58.2, 15.5, 14.4.
1,4,4-Tr ieth oxy-1,2-bu ta d ien e (20). This compound was
prepared according to a previously reported procedure.10
Additional spectroscopic data are included here. 1H NMR
(CDCl3): 6.81 (d, J ) 5.7 Hz, 1H), 5.85 (t, J ) 5.7 Hz, 1H),
4.89 (d, J ) 5.7 Hz, 1H), 3.62 (m, 6H), 1.23 (m, 9H). 13C NMR
(CDCl3): 196.4, 123.4, 105.5, 101.3, 65.0, 61.7, 15.5, 14.9.
Gen er a l P r oced u r e for th e Oxid a tion of P r op a r gylic
Alcoh ols. The propargylic alcohols were oxidized with the
Dess-Martin reagent.20 The secondary alcohol was dissolved
in dichloromethane (100 mL). This was cooled to -78 °C in a
dry ice/acetone bath. The Dess-Martin periodinane reagent
(1.5 equiv) was added. The reaction mixture was allowed to
warm to 25 °C over 3 h. It was then poured into saturated
4-Hexyn -3-on e (22b). 4-Hexyn-3-ol (21b) (2.0 g, 20.0 mmol)
was dissolved in dichloromethane (100 mL). The product was
obtained as a clear liquid (22b) (1.18 g, 12.3 mmol, 61% yield)
after following the procedure outlined above. This compound
matched the previously reported boiling point of 46 °C at 10
mm22 and the previously reported mass spectrometry data.23
There has been no published IR and NMR spectral data on
this compound. IR (NaCl): 2957, 2222, 1699, 1530, 1252, 1016
cm-1. 1H NMR (CDCl3): 2.55 (q, J ) 7.4 Hz, 2H), 2.02 (s, 3H),
1.13 (t, J ) 7.4 Hz, 3H). 13C NMR (CDCl3): 188.39, 89.69,
79.66, 38.37, 7.65, 3.56. HRMS EI: calcd for C6H8O (M)+,
96.0575; found, 96.0487.
4,4-Dieth oxy-2-bu tyn -1-ol (23). Acetal 18 (13.42 mL, 0.094
mol) was dissolved in THF (150 mL) and cooled to -78 °C.
Butyllithium (52.24 mL, 0.1311 mol of a 2.5 M solution in
hexanes) was added dropwise slowly over a period of 2 h. The
mixture was allowed to stir for 0.5 h at -78 °C, then
paraformaldehyde (9.25 g, 0.102 mol) was added, and the
mixture was allowed to warm to 25 °C. Ice water (30 mL) was
added, and the layers were separated. The aqueous layer was
extracted with EtOAc (3 × 50 mL). The organic layers were
combined and dried with MgSO4, and the solvent was removed
by rotary evaporation. The resulting liquid was vacuum-
distilled to afford a viscous liquid: bp 70-75 °C, 25 mmHg;
12.58 g, 0.080 mol, 85%. 1H NMR (CDCl3): 5.26 (t, J ) 1.4
Hz, 1H), 4.27 (br s, 2H), 3.62 (m, 4H), 2.23 (br s, 1H), 1.19 (t,
J ) 7.1 Hz, 6H). 13C NMR (CDCl3): 91.2, 83.7, 80.8, 60.9, 50.8,
15.0. IR (CDCl3): 3608.1, 3447.3, 3155.7, 2981,7, 2931.7,
2900.6, 1653.0, 1559.0, 1473.0, 1382.1, 1328.0 cm-1. Anal.
Calcd for C8H14O3: C, 60.73; H, 8.92. Found: C, 60.85; H, 8.92.
1-Tosyl-4,4-d ieth oxy-2-bu tyn e (24). In an adaptation of
a literature procedure,9 alkynol 23 (5.00 g, 0.032 mol) was
dissolved in distilled diethyl ether (60 mL) and p-toluenesul-
fonyl chloride (5.72 g, 0.030 mol) was added. The mixture was
cooled to -15 °C, and powdered KOH (5 equiv) (8.87 g, 0.158
mol) was added 1 equiv at a time over 30-45 min. The reaction
mixture was then allowed to stir at -15 °C for 90 min. Ice
water (80 mL) was then added, and the mixture was extracted
with diethyl ether (3 × 50 mL). The combined ether layers
were dried with MgSO4, and the solvent was removed under
reduced pressure. The remaining residue was then triturated
with petroleum ether (15 mL) and cooled to -78 °C, and the
solvent was decanted. The product was dried under vacuum
to yield a dark brown oil (9.55 g, 0.031 mol, 97%). 1H NMR
(CDCl3): 7.79 (d, J ) 8.3 Hz, 2H), 7.33 (d, J ) 8.3 Hz, 2H),
5.12 (t, J ) 1.5 Hz, 1H), 4.72 (d, J ) 1.5 Hz, 2H), 3.54 (m,
4H), 2.42 (s, 3H), 1.17 (t, J ) 7.0 Hz, 6H). 13C NMR (CDCl3):
(21) Bowden, K.; Heilbron, I. M.; J ones, E. R. H.; Weedon, B. C. L.
J . Chem. Soc. 1946, 39.
(22) Smith, W. N.; Kuehn, E. D. J . Org. Chem. 1973, 38, 3588.
(23) Bachiri, M.; Perros, P.; Verneuil, B.; Mouvier, G.; Carlier, P.
Org. Mass Spectrom. 1980, 15, 84.
(20) Dess, D. B.; Martin, J . C. J . Org. Chem. 1983, 48, 4155.

Cobaloxime-Substituted Carbonyl Compounds
Organometallics, Vol. 19, No. 14, 2000 2737
145.2, 132.9, 129.9, 128.1, 90.9, 84.3, 76.9, 61.0, 57.4, 21.7, 15.0.
IR (CDCl3): 3154.5, 2982.0, 2900.8, 1653.1, 1559.1, 1472.4,
1376.6, 1190.8, 1096.0 cm-1. EI HRMS: m/z calcd for C15H20O5S
(M+) 312.1031, found 312.1026. Anal. Calcd for C15H20O5S: C,
57.68; H, 6.45. Found: C, 57.96; H, 6.36.
°C overnight. The mixture was then poured into ice water (100
mL) containing pyridine (0.50 mL) and then extracted with
CH2Cl2 (4 × 25 mL). The CH2Cl2 extracts were combined and
dried (MgSO4), and the solvent was removed by rotary
evaporation. The crude product 1H NMR (CDCl3) was consis-
tent with structure 29: 8.60 (d, J ) 5.0 Hz, 2H), 7.75 (t, J )
5.0 Hz, 1H), 7.30 (t, J ) 5.0 Hz, 2H), 6.4 (d, J ) 12.8 Hz, 1H),
5.7 (s, 1H), 5.1 (d, J ) 12.8 Hz, 1H), 3.7 (q, J ) 6.9 Hz, 2H),
3.6 (q, J ) 7.1 Hz, 2H), 2.19 (s, 12H), 1.2 (t, J ) 6.9 Hz, 3H),
1.1 (t, J ) 7.1 Hz, 3H). This crude product was chromato-
graphed on silica (EtOAc) to yield a yellow solid (30) (0.144 g,
0.299 mmol, 12%); mp 143-145 °C dec. 1H NMR (CDCl3): 9.73
(d, J ) 7.2 Hz, 1H), 8.54 (d, J ) 7.0 Hz, 2H), 7.67 (t, J ) 7.1
Hz, 1H), 7.26 (t, J ) 7.1 Hz, 2H), 6.10 (d, J ) 7.2 Hz, 1H),
4.15 (s, 2H), 3.33 (q, J ) 7.0 Hz, 2H), 2.04 (s, 12H), 1.04 (t, J
) 7.0 Hz). 13C NMR (CDCl3): 186.9, 151.2, 150.3, 138.6, 138.3,
125.8, 71.5, 66.0, 15.6, 12.7. IR (CDCl3): 3155.5, 2984.3, 2902.1,
1653.0, 1559.3, 1471.1, 1382.5, 1216.5, 1094.6 cm-1. FAB
HRMS: m/z calcd for (M + H+) C19H28CoN5O6 482.1371, found
(M + H+) 482.1437. Anal. Calcd for C19H28CoN5O6: C, 47.41;
H, 5.86. Found: C, 47.28; H, 5.77.
(1-Oxo-2(E)-bu t en -3-yl)(p yr id in e)b is(d im et h ylglyoxi-
m a to)coba lt(III) (26a ). Cobaloxime chloride 28 (1.00 g, 2.50
mmol) was dissolved in degassed THF (30 mL) and cooled to
-20 °C. LiBH4 (0.993 mL, 1.99 mmol of a 2.0 M solution in
THF) was added, and the mixture was stirred (20 min). Allenyl
aldehyde 16a (1.50 g, 0.022 mol) was added, and the mixture
was allowed to warm to 25 °C overnight. The THF was
removed by rotary evaporation, and the remaining residue was
poured into ice water (100 mL) containing pyridine (0.75 mL).
The mixture was extracted with CH2Cl2 (4 × 50 mL) and dried
(MgSO4), and the solvent was removed by rotary evaporation.
The crude product was chromatographed on silica (EtOAc) to
yield a yellow-orange solid (26a ) (0.525 g, 1.20 mmol, 48%);
mp 158-160 °C dec. 1H NMR (CDCl3): 9.63 (d, J ) 7.0 Hz,
1H), 8.60 (d, J ) 6.3 Hz, 2H), 7.72 (t, J ) 6.3 Hz, 1H), 7.31 (t,
J ) 6.3 Hz, 2H), 6.21 (d, J ) 7.0 Hz, 1H), 2.12 (s, 3H), 2.09 (s,
12H). 13C NMR (CDCl3): 183.0, 150.5, 150.0, 138.0, 135.5,
125.4, 23.2, 12.4. IR (CDCl3): 3154.9, 2984.6, 2902.4, 1635.8,
1472.3, 1383.8, 1166.2, 1095.2 cm-1. FAB HRMS: m/z calcd
for C17H24CoN5O5 (M + H+) 438.1109, found 438.1167. Anal.
Calcd for C17H24CoN5O5: C, 46.69; H, 5.53. Found: C, 46.83;
H, 5.61.
(4,4-Dieth oxy-2-bu tyn -3-yl)(p yr id in e)bis(d im eth ylgly-
oxim a to)coba lt(III) (32). Cobaloxime chloride 28 (1.50 g, 3.72
mmol) was dissolved in degassed THF (45 mL) and cooled to
-20 °C. LiBH4 (1.49 mL of a 2.0 M solution, 2.97 mmol in THF)
was added, and the mixture was stirred for 20 min. Tosylate
24 (1.28 g, 4.41 mmol) was added, and the reaction mixture
was allowed to warm to 25 °C overnight. The mixture was
poured into ice water (200 mL) containing pyridine (0.75 mL),
and the orange product was extracted with CH2Cl2 (4 × 50
mL). The combined organic layers were dried (MgSO4), and
the solvent was removed by rotary evaporation. The crude
orange product was chromatographed on silica (EtOAc) to yield
an orange solid (0.703 g, 1.380 mmol, 37%); mp 124-126 °C
(1-Oxo-2(E)-p en ten -3-yl)(p yr id in e)bis(d im eth ylglyoxi-
m a to)coba lt(III) (26b). This complex was prepared using the
method described above using cobaloxime chloride 28 (1.50 g,
3.72 mmol), LiBH4 (1.49 mL, 2.97 mmol of a 2.0 M solution in
THF), and allenyl ketone 16b (1.50 g, 0.018 mol) to yield a
dark orange solid (26b) (0.671 g, 1.49 mmol, 40%); mp 183-
1
184 °C dec. H NMR (CDCl3): 8.61 (d, J ) 5.1 Hz, 2H), 7.72
1
dec. H NMR (CDCl3): 8.54 (d, J ) 7.6 Hz, 2H), 7.69 (t, J )
(t, J ) 5.1 Hz, 1H), 7.31 (t, J ) 5.1 Hz, 2H), 6.34 (s, 1H), 2.11
(s, 3H), 2.09 (s, 12H), 2.02 (s, 3H). 13C NMR (CDCl3): 192.2,
150.3, 150.0, 137.8, 130.1, 125.3, 31.6, 25.5, 12.2. IR (CDCl3):
3155.0, 2985.8, 2902.0, 1653.1, 1558.8, 1471.4, 1382.7, 1235.4,
1094.9 cm-1. Anal. Calcd for C18H26CoN5O5: C, 47.90; H, 5.81.
Found: C, 47.83; H, 5.80.
7.6 Hz, 1H), 7.28 (t, J ) 7.6 Hz, 2H), 4.99 (t, J ) 1.8 Hz, 1H),
3.50 (m, 4H), 2.16 (s, 12H), 1.89 (m, 2H), 1.16 (t, J ) 7.0 Hz,
6H). 13C NMR (CDCl3): d 150.2, 150.1, 137.7, 125.3, 94.0, 92.5,
78.6, 60.7, 60.3, 15.1, 12.3. IR (CDCl3): 3156.8, 2984.0, 2901.6,
1646.1, 1559.1, 1237.7, 1167.0, 1096.0 cm-1. HRMS FAB: m/z
calcd for C21H32CoN5O6 509.1684, found 509.1700. Anal. Calcd
for C21H32CoN5O6: C, 49.51; H, 6.33. Found: C, 49.65; H, 6.34.
Gen er a l P r oced u r e for th e Syn th esis of (Z)-Alk en e-
Con ta in in g Un sa tu r a ted Acyl Com p lexes. Cobaloxime
chloride 28 was suspended in degassed MeOH (20 mL)
containing NaOH (3.3 equiv) at 0 °C and was reduced with
NaBH4 (1.8 equiv). Ynone (2.5 equiv) was added, followed by
the dropwise addition of acetic acid (approximately 7-8 drops)
until the solution turned orange-red. The reaction mixture was
then immediately poured into ice water containing pyridine
(0.75 mL). Depending on the presence or absence of a precipi-
tate, the product was either filtered and washed with water
(500 mL) or extracted with EtOAc (4 × 100 mL), dried with
MgSO4, and concentrated under reduced pressure. The crude
product was chromatographed on silica gel (EtOAc) to yield
yellow-orange solids.
(4,4-Diet h oxy-1-oxo-2(Z)-b u t en -3-yl)(p yr id in e)b is(d i-
m eth ylglyoxim a to)coba lt(III) (27). Cobaloxime chloride 28
(1.00 g, 2.47 mmol) was suspended in degassed absolute EtOH
(20 mL) and cooled to -20 °C. LiBH4 (0.990 mL of a 2.0 M
solution, 1.98 mmol in THF) was added, and the mixture was
allowed to stir for 45 min at -20 °C. Allene 20 (0.461 g, 2.47
mmol) was added dropwise slowly, and the mixture was
allowed to warm to 25 °C overnight. The mixture was then
poured into ice water (100 mL) containing pyridine (0.50 mL)
and then extracted with CH2Cl2 (4 × 25 mL). The CH2Cl2
extracts were combined and dried (MgSO4), and the solvent
was removed by rotary evaporation. The remaining residue
was chromatographed on silica (EtOAc) to yield a yellow solid
(0.970 g, 1.85 mmol, 75%); mp 160-162 °C dec. 1H NMR
(CDCl3): 9.95 (d, J ) 7.0 Hz, 1H), 8.55 (d, J ) 7.0 Hz, 2H),
7.67 (t, J ) 7.0 Hz, 1H), 7.27 (t, J ) 7.0 Hz, 2H), 6.01 (d, J )
7.0 Hz, 1H), 5.29 (s, 1H), 3.49 (q, J ) 7.1 Hz, 2H), 3.22 (q, J )
7.1 Hz, 2H), 2.04 (s, 12H), 1.02 (t, J ) 7.1 Hz, 6H). 13C NMR
(CDCl3): 190.1, 151.2, 150.4, 138.7, 138.3, 125.8, 103.5, 63.6,
15.9, 12.7. IR (CDCl3): 3155.1, 2983.5, 2901.4, 1652.8, 1559.2,
1471.8, 1382.1, 1297.3, 1216.3, 1167.2, 1098.0 cm-1. FAB
HRMS: m/z calcd for C21H32CoN5O7 525.1633; found 525.1637.
Anal. Calcd for C21H32CoN5O7: C, 48.00; H, 6.14. Found: C,
48.25; H, 6.20.
(1-P h en yl-1-oxo-2(Z)-p r op en -3-yl)(p yr id in e)bis(d im e-
th ylglyoxim a to)coba lt(III) (33b). Cobaloxime chloride 28
(1.24 g, 3.10 mmol) was dissolved in degassed MeOH. Follow-
ing reduction with NaBH4, 1-phenyl-2-propyn-1-one (22b) (2.5
equiv) was added. After continuing with the above procedure,
the reaction mixture was poured into the ice water/pyridine
mixture. The product precipitated out and was vacuum filtered
to yield a yellow solid (33b) (0.511 g, 1.02 mmol, 33% yield);
decomposes at 176 °C. IR (NaCl): 2957, 2923, 1725, 1657,
4-Eth oxy-1-oxo-2(Z)-bu ten -3-yl-(p yr id in e)bis(d im eth -
ylglyoxim a to)coba lt(III) (30). Cobaloxime chloride 28 (1.00
g, 2.47 mmol) was suspended in degassed THF (20 mL) and
cooled to -20 °C. LiBH4 (0.990 mL of a 2.0 M solution, 1.98
mmol in THF) was added, and the mixture was allowed to stir
for 45 min at -20 °C. Allene 20 (0.461 g, 2.47 mmol) was added
dropwise slowly, and the mixture was allowed to warm to 25
1
1547, 1446 cm-1. H NMR (CDCl3): 17.80 (bs, 2H), 8.34 (d, J
) 6.2 Hz, 2H), 7.76 (d, J ) 8.3 Hz, 2H), 7.53 (t, J ) 7.6 Hz,
1H), 7.31 (t, J ) 6.9 Hz, 1H), 7.25 (t, J ) 7.4 Hz, 2H), 7.11 (d,
J ) 6.4 Hz, 2H), 6.17 (d, J ) 10.6 Hz, 1H), 6.08 (d, J ) 10.6
Hz, 1H), 1.76 (s, 12H). 13C NMR (CDCl3): 194.82, 150.51,
149.66, 137.89, 137.80, 137.18, 132.55, 129.34, 128.08, 125.23,

2738 Organometallics, Vol. 19, No. 14, 2000
Hayes et al.
11.95. HRMS FAB (m/z): calcd for C22H26O5N5Co, 499.1266;
found 499.1259. Anal. Calcd for C22H26O5N5Co: C, 52.91; H,
5.25. Found: C, 53.28; H, 5.64.
dark orange solid (39) (0.277 g, 0.60 mmol, 48% yield);
decomposes at 170 °C. IR (NaCl): 2957, 2923, 1708, 1556,
1
1438, 1227 cm-1. H NMR (CDCl3): 18.04 (bs, 2H), 8.56 (d, J
) 6.3 Hz, 2H), 7.66 (t, J ) 6.2 Hz, 1H), 7.25 (t, J ) 6.4 Hz,
2H), 5.26 (q, J ) 6.7 Hz, 1H), 3.13 (s, 2H), 2.03 (s, 12H), 2.02
(s, 3H), 1.48 (d, J ) 6.7 Hz, 3H). 13C NMR (CDCl3): 205.95,
150.51, 149.99, 137.45, 127.18, 125.23, 125.08, 47.87, 29.09,
14.84, 12.01. DEPT (CDCl3): 205.95 (C), 150.51 (C), 149.99
(CH), 137.45 (CH), 127.18 (CH), 125.23 (C), 125.08 (CH), 47.87
(CH2), 29.09 (CH3), 14.84 (CH3),12.01 (CH3). HRMS FAB (m/
z): calcd for C19H28O5N5Co, 465.1422; found 465.1429. Anal.
Calcd for C19H28O5N5Co: C, 49.04; H, 6.06. Found: C, 49.22;
H, 6.13.
1-P r op en -3-a l-1-ylp yr id in eb is(d im et h ylglyoxim a t o)-
coba lt(III) (43a ). Cobalt(II) acetate tetrahydrate (40) (1.001
g, 4.01 mmol), dimethylglyoxyime (0.928 g, 8.00 mmol), pyri-
dine (1.0 mL, 12.4 mmol), and zinc dust (1.378 g, 21.1 mmol)
were all combined in degassed THF (70 mL). The reaction
mixture was refluxed for 15 min and then allowed to cool to
room temperature. Propionaldehyde diethyl acetal (0.90 mL,
6.29 mmol) was then added. The reaction mixture was refluxed
an additional hour. Upon cooling to 25° C, approximately 7-8
drops of acetic acid were added. The mixture was then poured
into ice water (50 mL) containing 5 drops of pyridine. The
product was extracted with EtOAc (5 × 100 mL), dried with
MgSO4, and concentrated under reduced pressure. The crude
product was purified by column chromatography on silica gel
using EtOAc to yield the product as a bright yellow solid (0.121
g, 0.286 mmol, 7%); decomposes at 151-153° C. 1H NMR
(CDCl3): 9.19 (d, J ) 7.6 Hz, 1H), 8.61 (d, J ) 4.1 Hz, 2H),
8.39 (d, J ) 14.7 Hz, 1H), 7.78 (t, J ) 7.6 Hz, 1H), 7.37 (t, J
) 7.3 Hz, 2H), 6.22 (dd, J ) 14.8, 7.6 Hz, 1H), 2.13 (s, 12H).
13C NMR (CDCl3): 189.49, 150.57, 150.38, 141.99, 138.57,
125.92, 12.70. IR (NaCl): 2921, 2794, 2707, 1664, 1559, 1546,
1232, 1094, 1072 cm-1. Anal. Calcd for C16H22CoN5O5: C,
45.64; H, 5.24. Found: C, 45.59; H, 5.34.
(1,1-Dieth oxy-2(Z)-p r op en -3-yl)(p yr id in e)bis(d im eth -
ylglyoxim a to)coba lt(III) (34) a n d (1-Oxo-2(Z)-p r op en -3-
yl)(pyr idin e)bis(dim eth ylglyoxim ato)cobalt(III) (35). Com-
plex 34 was synthesized by analogy with a literature pro-
cedure.16 Cobalt(II) chloride hexahydrate (CoCl2‚6H2O) (5.00
g, 21.0 mmol) and dimethylglyoxime (4.87 g, 42.0 mmol) were
dissolved in degassed methanol (150 mL). Sodium hydroxide
(1.68 g, 42.0 mmol) in water (15 mL) was added followed by
pyridine (1.66 g, 21.0 mmol). The reaction mixture was cooled
to -10 °C in a dry ice/acetone bath and stirred under nitrogen
for 15 min. Subsequently, another equivalent of sodium
hydroxide (0.84 g, 21.0 mmol) in water (7 mL) and NaBH4 (1.17
g, 32.0 mmol) in water (20 mL) were added. Propionaldehyde
diethylacetal (18) (4.03 g, 32.0 mmol) was added by syringe,
and the solution was allowed to warm gradually to 25 °C over
a few hours. The reaction mixture was concentrated under
reduced pressure to a volume of about 50 mL and then poured
into ice water (300 mL) containing pyridine (2 mL). The orange
precipitate (34) (7.99 g, 16.1 mmol, 77% yield) was collected
by vacuum filtration and washed with water; mp 171 °C. IR
(NaCl): 2974, 2948, 2872, 1556, 1446, 1287, 1227, 1083 cm-1
.
1H NMR (CDCl3): 18.36 (bs, 2H), 8.60 (d, J ) 6.3 Hz, 2H),
7.70 (t, J ) 6.2 Hz, 1H), 7.30 (t, J ) 6.1 Hz, 2H), 6.27 (d, J )
7.9 Hz, 1H), 5.18 (d, J ) 7.9 Hz, 1H), 5.08 (t, J ) 7.9 Hz, 1H),
3.60 (q, J ) 7.1 Hz, 2H), 3.46 (q, J ) 7.1 Hz, 2H), 2.04 (s, 12H),
1.14 (t, J ) 7.1 Hz, 6H). 13C NMR (CDCl3): 150.17, 149.83,
137.74, 135.45, 125.53, 125.28, 99.81, 61.08, 15.59, 12.11. Anal.
Calcd for C20H32O6N5Co: C, 48.29; H, 6.48. Found: C, 48.16;
H, 6.36. Complex 34 (7.99 g, 16.1 mmol) was then suspended
in water and cooled to 0 °C. Acetic acid was added dropwise
until the solution was at pH ) 4, and then the solution was
warmed to 25 °C and stirred (2 h). The solution was then
poured into ice water containing a few drops of pyridine, and
35 was isolated by vacuum filtration (6.028 g, 14.2 mmol, 88%).
This complex (35) proved identical by 1H NMR comparison
with material we had prepared previously by an alternate
procedure.6
(2-Oxo-3(E)-b u t en -4-yl)(p yr id in e)bis(d im et h ylglyoxi-
m a to)coba lt(III) (43b). Cobalt(II) acetate tetrahydrate (40)
(1.0 g, 4.02 mmol), dimethylglyoxime (0.93 g, 8.03 mmol),
pyridine (0.95 g, 12.0 mmol), and zinc dust (2.61 g, 40.2 mmol)
were all combined in degassed THF (50 mL). The reaction
mixture was refluxed for 10 min and then allowed to cool back
down to room temperature. 3-Butyn-2-one (0.41 g, 6.02 mmol)
was then added. The reaction mixture was refluxed for an
additional hour. Upon cooling to 25 °C, approximately 7-8
drops of acetic acid were added. The reaction mixture was then
poured into ice water containing pyridine (0.75 mL). The
product was extracted with EtOAc (4 × 100 mL), dried with
MgSO4, and concentrated under reduced pressure. The crude
product was chromatographed on silica gel (EtOAc) to yield a
bright orange solid (43b) (1.56 g, 3.57 mmol, 89% yield);
decomposes at 228 °C. IR (NaCl): 3480, 2957, 2923, 1649,
(3-Oxo-5-h exen -5-yl)(pyr idin e)bis(dim eth ylglyoxim ato)-
coba lt(III) (38). Cobaloxime chloride 28 (1.68 g, 4.17 mmol)
was dissolved in degassed MeOH. Following cobaloxime reduc-
tion with NaBH4, 4-hexyn-3-one (22b) (2.5 equiv) was added.
After continuing with the above procedure, the reaction
mixture was poured into the ice water/pyridine mixture. The
product was extracted with EtOAc (4 × 100 mL), dried with
MgSO4, and concentrated under reduced pressure. The crude
product was chromatographed on silica gel (EtOAc) to yield a
dark orange solid (38) (0.685 g, 1.47 mmol, 35% yield); mp
165-167 °C. IR (NaCl): 3472, 2974, 2931, 1707, 1556, 1438,
1227 cm-1. 1H NMR (CDCl3): 8.58 (d, J ) 6.3 Hz, 2H), 7.69 (t,
J ) 7.5 Hz, 1H), 7.28 (t, J ) 6.3 Hz, 2H), 4.95 (d, J ) 1.7 Hz,
1H), 4.19 (d, J ) 1.7 Hz, 1H), 3.07 (s, 2H), 2.34 (q, J ) 7.3 Hz,
2H), 2.07 (s, 12H), 0.95 (t, J ) 7.3 Hz, 3H). 13C NMR (CDCl3):
209.52, 150.51, 150.04, 137.62, 137.37, 125.21, 119.62, 52.89,
34.64, 12.09, 8.02. DEPT (CDCl3): 209.52 (C), 150.51 (C),
150.04 (CH), 137.62 (CH), 137.37 (C), 125.21 (CH), 119.62
(CH2), 52.89 (CH2), 34.64 (CH2), 12.09 (CH3), 8.02 (CH3).
HRMS FAB (m/z): calcd for C19H28O5N5Co, 465.1422; found
465.1431. Anal. Calcd for C19H28O5N5Co: C, 49.04; H, 6.06.
Found: C, 48.82; H, 6.19.
(2-Oxo-4(E)-h exen -4-yl)(p yr id in e)bis(d im eth ylglyoxi-
m a to)coba lt(III) (39). Cobaloxime chloride 28 (0.50 g, 1.24
mmol) was dissolved in degassed MeOH. Following cobaloxime
reduction with NaBH4, 3-hexyn-2-one (36a ) (2.5 equiv) was
added. After continuing with the above procedure, the reaction
mixture was poured into the ice water/pyridine mixture. The
product was extracted with EtOAc (4 × 100 mL), dried with
MgSO4, and concentrated under reduced pressure. The crude
product was chromatographed on silica gel (EtOAc) to yield a
1
1556, 1235 cm-1. H NMR (CDCl3): 18.16 (bs, 2H), 8.62 (d, J
) 6.3 Hz, 2H), 8.21 (d, J ) 14.9 Hz, 1H), 7.78 (t, J ) 7.6 Hz,
1H), 7.38 (t, J ) 6.6 Hz, 2H), 6.08 (d, J ) 14.9 Hz, 1H), 2.13
(s, 12H), 2.12 (s, 3H). 13C NMR (CDCl3): 193.07, 150.90,
150.01, 149.52, 139.36, 138.05, 125.45, 26.22, 12.23. HRMS
FAB (m/z): calcd for C17H25O5N5Co (MH)+, 438.1188; found
438.1184. Anal. Calcd for C17H24O5N5Co: C, 46.69; H, 5.53.
Found: C, 46.86; H, 5.59.
3-P h en yl-1-p r op en -3-on e-1-ylp yr id in ebis(d im eth ylgly-
oxim a to)coba lt(III) (43c). Cobalt(II) acetate tetrahydrate
(40) (1.006 g, 4.04 mmol), dimethylglyoxyime (0.930 g, 8.02
mmol), pyridine (1.0 mL, 12.4 mmol), and zinc dust (1.360 g,
20.8 mmol) were all combined in degassed THF (70 mL). The
reaction was refluxed for 15 min and then allowed to cool to
room temperature. 1-Phenyl-2-propyn-1-one (0.781, 6.01 mmol)
was then added. The reaction mixture was refluxed an
additional hour. Upon cooling to 25° C, approximately 7-8
drops of acetic acid were added. The reaction was then poured
into ice water (50 mL) containing 5 drops of pyridine. The

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

2740 Organometallics, Vol. 19, No. 14, 2000
Hayes et al.
reduced pressure. The crude product was chromatographed on
silica gel with EtOAc and eluted last (first orange band
contains titanium byproduct) to yield a bright orange solid (46)
(0.106 g, 0.244 mmol, 53% yield); decomposes at 171 °C. IR
(NaCl): 2957, 2898, 1556, 1438, 1227 cm-1. 1H NMR (CDCl3):
18.32 (bs, 2H), 8.58 (d, J ) 6.3 Hz, 2H), 7.70 (t, J ) 7.6 Hz,
1H), 7.30 (t, J ) 7.5 Hz, 2H), 6.40 (d, J ) 14.0 Hz, 1H), 5.92
(d, J ) 14.0 Hz, 1H), 4.61 (d, J ) 1.3 Hz, 1H), 4.52 (d, J ) 1.3
Hz, 1H), 2.10 (s, 12H), 1.68 (s, 3H). 13C NMR (CDCl3): 150.09,
149.98, 149.49, 149.00, 137.45, 125.23, 125.17, 110.92, 12.11,
11.96. HRMS FAB (m/z): calcd for C18H27O4N5Co (MH)+
436.1395; found 436.1387.
chased with the partial support of the NSF (CHE-
9708077) and the NCBC (9703-IDG-1007). Low-resolution
mass spectra were obtained on an instrument purchased
with the partial support of NSF (CHE-9007366). The
Duke University Center for Mass Spectrometry per-
formed high-resolution mass spectral analyses. T.A.A.
acknowledges Graduate Fellowships from the Hearst
Foundation (1994-1995), the Exxon Education Founda-
tion (1995-1996), and NSF (1996-1997).
Su p p or tin g In for m a tion Ava ila ble: Tables giving ad-
ditional details of the X-ray structure determinations, atomic
coordinates and isotropic thermal parameters, and anisotropic
displacement parameters for 38, 39, and 45a . This material
is available free of charge via the Internet at http://pubs.acs.org.
Ack n ow led gm en t. We thank the National Science
Foundation (CHE-9726172) and the Camille and Henry
Dreyfus Foundation (Henry Dreyfus Teacher-Scholar
Award to M.E.W, 1994-1999) for their support. High-
field NMR spectra were obtained on instruments pur-
OM000230M