Isomerization of 2-methyl-3-butenenitrile with (bis-diphenylphosphinoferrocene)nickel compounds: Catalytic and structural studies

Article abstract of DOI:10.1016/j.jorganchem.2006.05.042

The catalytic isomerization of 2-metyl-3-butenenitrile to 3-pentenenitrile was carried out by (dppf)Ni species (dppf = bis-diphenylphosphinoferrocene) in the absence and the presence of Lewis acids. Studies in solution reveal the intermediacy of Ni(II) allyl complexes. Addition of Lewis acids such as BEt₃ allow the crystallization and full characterization of the latter by X-ray diffraction studies.

Full text of DOI:10.1016/j.jorganchem.2006.05.042

Journal of Organometallic Chemistry 691 (2006) 3895–3901
www.elsevier.com/locate/jorganchem
Isomerization of 2-methyl-3-butenenitrile with
(bis-diphenylphosphinoferrocene)nickel compounds: Catalytic
and structural studies
a
b
´
´
Alberto Acosta-Ramırez , Miguel Munoz-Hernandez ,
˜
c
a,
*
´
William D. Jones , Juventino J. Garcıa
a
Facultad de Quı´mica, Universidad Nacional Auto´noma de Me´xico, Me´xico City, Me´xico D.F. 04510, Mexico
Centro de Investigaciones Quı´micas, Universidad Auto´noma del Estado de Morelos, Morelos 62210, Mexico
b
c
Department of Chemistry, University of Rochester, Rochester, NY 14627, USA
Received 28 April 2006; received in revised form 19 May 2006; accepted 19 May 2006
Available online 3 June 2006
Abstract
The catalytic isomerization of 2-metyl-3-butenenitrile to 3-pentenenitrile was carried out by (dppf)Ni species (dppf = bis-diph-
enylphosphinoferrocene) in the absence and the presence of Lewis acids. Studies in solution reveal the intermediacy of Ni(II) allyl com-
plexes. Addition of Lewis acids such as BEt3 allow the crystallization and full characterization of the latter by X-ray diffraction studies.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Nitrile; Isomerization; Catalytic; Nickel; X-ray structure
1. Introduction
HCN addition to 4PN, in presence of a Ni(0) complex and
Lewis acids (LA) as co-catalysts [3,4].
The production of adiponitrile (AdN) is among the most
important industrial processes in existence. AdN is a pre-
cursor of 1,6-hexanediamine, which is used for the prepara-
tion of Nylon 66 [1]. AdN is prepared by the double
catalytic hydrocyanation of butadiene using Ni(0)-phos-
phite complexes (Scheme 1). The first addition of HCN
leads both to the desirable linear isomer 3-pentenenitrile
(3PN) and to the undesirable branched isomer 2-methyl-
3-butenenitrile (2M3BN) in a variable ratio, some times
quoted as a 2:1 ratio, respectively [2]. Thermodynamics
favours 3PN (about 9:1) and 2M3BN may be isomerized
to 3PN in the presence of a nickel catalyst, through a
CACN bond breaking/forming reaction involving a Ni(II)
allyl cyanide complex. The selective anti-Markovnikov
addition of the second HCN to yield AdN requires the con-
current isomerization of 3PN to 4-pentenenitrile (4PN) and
Since 1984, several mechanistic studies have been made
using [(phosphite)Ni(0)] complexes, cyano-olefins, and
HCN, to yield additions to C@C bonds, including the
use of Lewis acids in such processes [5–7]. More recently,
the use of [Ni(COD)2] as catalytic precursor, in combina-
tion with P-donor-bidentate ligands such as phosphines,
[8–11] phosphonites [9] and phosphites, [12] has been
reported to achieve the transformation of the branched
nitrile (2M3BN) to the linear nitrile (3PN). Additionally,
this reaction has been studied in aqueous media [13] and
ionic liquids [14].
Due to the continued interest of our group in the activa-
tion of CACN bonds in alkyl, aryl, and heterocyclic nitriles
with the use of nickel complexes, [15,16] we have expanded
the scope of these investigations to study the related reac-
tions involving allyl nitriles and the isomerization of
cyano-olefins [17]. We report here the study of the catalytic
isomerization of 2M3BN using nickel(0) compounds with
bis-diphenylphosphinoferrocene (dppf).
*
Corresponding author. Tel.: +52 55 56223514; fax: +52 55 56162010.
´
E-mail address: juvent@servidor.unam.mx (J.J. Garcıa).
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.05.042

3896
A. Acosta-Ramı´rez et al. / Journal of Organometallic Chemistry 691 (2006) 3895–3901
HCN
Ni(0)/ phosphite
Ni(0) / phosphite
Lewis Ac
+
CN
CN
CN
CN
HCN
CN
2M3BN
4PN
3PN
Adiponitrile (AdN)
Ni(0)/ phosphite
2M3BN: 2-methyl-3-butenenitrile
3PN: 3-pentenenitrile
4PN: 4-pentenenitrile
Scheme 1.
2. Results and discussion
The use of Lewis acids with the Ni(COD)2/dppf cata-
lytic system resulted in a dramatic drop in catalytic activity,
giving no conversion at all after 1 h of reaction. On using
ZnCl2, 5 h at 100 ꢁC were necessary to obtain total conver-
sion with a moderate yield of 3PN (54%). The reaction
using BEt3 gave just 10% conversion after 120 h. In all
the cases where activity was observed (entries 1–3, 5 and
7), the other nitriles produced were mainly Z-2-methyl-2-
butenenitrile, with small amounts of cis-2-pentenenitrile
and E-2-methyl-2-butenenitrile.
2.1. Isomerization of 2M3BN using Ni(0) compounds
The isomerization of neat 2M3BN using [Ni(COD)2] as
catalyst precursor and dppf, both in the presence and the
absence of LA, was explored at 100 ꢁC. The corresponding
catalytic results using a 110-fold excess of substrate are
summarized in Table 1.
The most active catalytic system found was that of
[Ni(COD)2] and dppf without the use of Lewis acids
(entries 1–3), producing 79% conversion and 67% yield of
3PN in 1 h. After 2.5 h, all the substrate was converted,
with a yield of 83% for 3PN. This result is slightly better
than the one reported by Sabo–Etienne’s group using
PPh3 under similar reaction conditions (96% conversion,
3 h, 81% 3PN), [8] which in our hands and reaction appa-
ratus, systematically gave 58% yield. The system reported
herein also outperformed in terms of activity and selectivity
the bis(2-diphenylphosphinophenyl)ether (DPEphos) cata-
lytic system reported by Vogt and co-workers [10]. The
reaction was followed up to a 75% conversion, but the pre-
cise yield of 3PN was not reported, and the formation of
additional by products was not mentioned. In our hands
and in our apparatus, the same experiment was followed
up to 90% conversion at 16 h, with a yield of 82% of
3PN and 8% other nitriles (3:1, cis-2-pentenenitrile: Z-2-
methyl-butenenitrile).
2.2. Synthesis and characterization of Ni(II)-allyl cyanide
complex (1)
The reaction of [Ni(COD)2] with one equivalent of dppf
in a THF solution produced an instantaneous color change
from yellow to orange. The 31P{1H} NMR spectrum in tol-
uene-d8 revealed the presence of a singlet at 33.0 ppm,
assigned to the complex [Ni(COD)(dppf)]. Addition of 1
equivalent of 2M3BN to [Ni(COD)(dppf)] produced a
color change to red to yield complex 1 (Scheme 2).
The 31P{1H} NMR spectrum of 1 in toluene-d8 at room
temperature showed several broad signals in the range of d
20.6–13.3, which did not change on cooling to À60 ꢁC, i.e.,
a low-temperature limit was not observed. Similar behavior
1
was observed by H NMR at room temperature. A COSY
spectrum allowed us to propose the existence of two species
or conformers for the allyl cyanide complex in a 1:1 ratio.
Table 1
Catalytic isomerization of 2M3BN
[Ni]
CN
CN
Entry
System
t (h)
Conversion (%)
Yield of 3-PN (%)
Other nitriles (%)
1
2
3
4
5
6
7
[Ni(COD)2]/dppf
[Ni(COD)2]/dppf
[Ni(COD)2]/dppf
[Ni(COD)2]/dppf/ZnCl2
[Ni(COD)2]/dppf/ZnCl2
[Ni(COD)2]/dppf/BEt3
[Ni(COD)2]/dppf/BEt3
1
2
2.5
1
5
1
79
93
100
0
100
0
67
76
83
–
54
–
12
17
16
–
46
–
120
10
7
3
Neat substrate:ligand:[Ni(COD)2]:Lewis acid = 110:1:1:1, T = 100 ꢁC. 2M3BN conversion % and yield were obtained by GC–MS and confirmed by 1H
NMR spectroscopy. GC error 1%.

A. Acosta-Ramı´rez et al. / Journal of Organometallic Chemistry 691 (2006) 3895–3901
3897
(Ph)2
2M3BN
-COD
P(Ph)2
P(Ph)2
CN
P
-COD
THF
[Ni(COD)2]
Fe
+
[Ni(COD)(dppf)]
Ni
Fe
THF
P
(Ph)2
1
Scheme 2.
(Ph)2
P
N
(Ph)2
P
C
N
C
CH3
H
CH3
Ni
Fe
Ni
Fe
P
Hanti
P
H
(Ph)2
(Ph)2
Hanti
Hsyn
Hsyn
A
B
(Ph)
P
N
2
(Ph)2
P
N
C
C
CH
3
Ni
Fe
Ni
Hsyn
(Ph)2
CH3
Fe
anti
H
H
P
P
(Ph2)
H
Hanti
syn
H
syn
anti
(Ph)2
P
N
C
(Ph)2
P
CH3
H
N
CH3
C
H
Ni
Fe
H
Ni
Fe
P
(Ph)2
P
H
(Ph)2
H
H
D
C
Scheme 3. p–r–p isomerization.
Both species may be assigned to the syn and anti conform-
ers of the allyl moiety, formed via a p–r–p isomerization
(Scheme 3), but by analogy to complex 3, vide infra, there-
fore at least one is likely to be the syn isomer [18]. However,
we cannot discard the co-formation of species A, B, C or D
in the same isomerization process.
In agreement with the existence of at least two species in
solution, two broad resonances for each type of allyl pro-
ton environment were observed at: d 4.82 and 4.71 (CH
central), 4.19 and 4.15 (CHMe), 2.77 and 2.66 (CHH),
1.77 and 1.68 (CH3), and 1.55 and 1.44 (CHH). This was
also corroborated by 13C{1H} NMR spectroscopy, where
two signals for each carbon of the allyl ligand were detected
(d 112.7 and 111.7 (CH central), 85.3 and 82.7 (CHMe),
48.9 and 47.3 (CH2), and 18.7 and 17.8 (CH3)). The CN
ligand gives one broad signal only at 145.6.
Most of the signals in the 1H and 13C{1H} NMR spectra
are in the range reported for closely related allyl com-
pounds with diphenylphosphinobutane (dppb), [8] with
the exception of the resonance for the central CH of the
allyl moiety, located at d 112.7 and 111.7 for both isomers
containing dppf and reported at 96.2 for dppb. NMR
assignments were in most cases corroborated by a series
of 2D NMR experiments.

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A. Acosta-Ramı´rez et al. / Journal of Organometallic Chemistry 691 (2006) 3895–3901
2.3. Synthesis and characterization of Ni(II) allyl cyanide–
Lewis acid complexes (2) and (3)
but with a coordinated LA to the CN moiety or alterna-
tively to the cation [Ni(dppf)(p-allylMe)]+ which can be
static because it is a d8 square planar, having the cyanide
out of the coordination sphere due to removal by the LA
[17]. Alternatively, the unchanged doublets can also be
associated with a 4-coordinate Zn species, in different coor-
dination environments, as represented in Scheme 4. Closely
related species have been structurally characterized by Vogt
and co-workers [10].
The in situ reaction of [Ni(COD)(dppf)] in THF with an
equimolar ratio of 2M3BN/ZnCl2 or 2M3BN/BEt3 in THF
solution produced a red–orange solution in either case.
After evaporation of the solvent an orange solid for com-
plex 2 and a red–orange solid for complex 3 were obtained
(Scheme 4).
The 31P{1H} NMR spectrum in CD2Cl2 at room tem-
perature for complex 2 displayed two overlapping very
broad signals roughly centered at 24.6 and 23 ppm, indica-
tive of an interchange, and also two sharp doublets at 24.5
and 23.1 ppm (2JP–P = 19.5 Hz) (see Fig. 1a). On cooling
the sample to 0 ꢁC, the broad overlapping signals begin
to sharpen into two signals at d 25.4 and 22.5. Total deco-
alescence is reached at À60 ꢁC, resulting in two doublets at
d 25.7 and 22.3 (2JP–P = 20.1 Hz, 70%), along with the two
doublets originally observed at room temperature (d 24.5
In agreement with the above description, the H NMR
1
spectrum for complex 2 at room temperature displays
two sets of signals for each allyl group proton, with signals
located at: d 5.81 and 5.55 (m, CH central), 3.35 and 3.05
3
(m, CHMe), 2.63 and 2.55 (d, JH–H = 14.1 Hz, CHH),
3
1.63 and 1.61 (d, JH–H = 13.3 Hz, CHH), and 1.72 (d,
3
3JH–H = 6.6 Hz, CH3) and 1.4 (d, JH–H = 7.2 Hz, CH3).
In sharp contrast, the 13C{1H} spectrum at room tempera-
ture displayed only one resonance for each carbon of the
allylic moiety at d 88.4 (CH central), 69.6 (CHMe), 51.5
(CH2) and 20.5 (CH3), the resonance for CN appearing
at 144 ppm. All the above quoted chemical shifts are simi-
lar to the ones reported in closely related allylic systems
[10].
2
and 23.1, JP–P = 19.5 Hz, 30%) that remain unchanged.
The two doublets involved in coalescence are for one iso-
mer, probably the syn isomer, based on the X-ray structure
determined for 3, vide infra, that undergoes rotation upon
warming. The unchanging doublets can be assigned again
with the related species C or D, depicted in Scheme 3,
Complex 3 presents a fluxional behavior in the 31P{1H}
NMR spectrum, i.e., a very broad signal at room tempera-
LA
2M3BN
Lewis A.c
-COD
(Ph)2
P
N
C
P(Ph)2
-COD
[Ni(COD)2]
Fe
+
[Ni(COD)(dppf)]
Ni
Fe
THF
THF
P(Ph)2
P
(Ph)2
2 LA= ZnCl2
3 LA= BEt3
Scheme 4.
(b)
(a)
Fig. 1. Variable temperature 31P{1H} NMR for complexes 2 (a) and 3 (b). Signals at d 22.8 in (a) and 25.1 ppm in (b) are impurities.

A. Acosta-Ramı´rez et al. / Journal of Organometallic Chemistry 691 (2006) 3895–3901
3899
ture located at d 20.9, indicative of exchange, that on cool-
ing to À60ꢁC decoaleses to give two sharp doublets located
at d 34.4 and 10.5 ppm (2JP–P = 32.9 Hz) (see Fig. 1b). The
activation energy for this process, again assigned as allyl
group rotation, was determined to be 11.0 kcal Æ molÀ1
,
which is almost half of the one reported in the case of cat-
ionic d8 square planar nickel-allylic systems [19].
The 1H NMR spectrum for complex 3 displays only one
signal for each allyl group proton, at room temperature: d
4.83 (pq, CH central), 2.90 (m, CHMe), 2.98(m, CHH),
3
1.51 (m, CHH), and 1.44 (d, JH–H = 5.1 Hz, CH3). The
bonding of BEt3 to the CN moiety was confirmed by
the upfield shift to d 0.63 (BCH2) and 0.09 (CH3) [20].
The 13C{1H} spectrum for complex 3 displays the relevant
signals assigned as follows: the allyl ligand at d 98.4 (CH
central), 86.6 (CHMe), 52.2 (CH2) and 15.7 (CH3) ppm;
the CN ligand at 142.2. The carbons of the ethyl groups
for BEt3 produce resonances at d 20.8 (CH2) and 11.2 (CH3).
Crystals suitable for X-ray diffraction studies of complex
3, isolated from the catalytic reaction mixture using BEt3,
were obtained upon cooling the mixture to À35 ꢁC in the
dry box. A summary of crystallographic results and the
molecular structure of complex 3 are shown in Table 2
and Fig. 2, respectively. The geometry around the Ni center
is pseudotetrahedral, as observed for the structure of
[Ni(DPEphos)(g3-1-Me–C3H4)(CN–ZnCl2ÆEtOH)], [10] in
contrast to the reported [Ni(dppb)(g3-1-Me–C3H4)(CN)],
Fig. 2. Molecular structure of complex 3 at the 30% probability. Selected
˚
bond distances in A: Ni–P1(2.3305(14)), Ni–P2 (2.2143(14)), Ni–
C45(1.898(5)), Ni–C35(2.075(4)), Ni–C36(2.007(5)), Ni–C37(2.150(5)),
C35–C36(1.409(7)), C36–C37(1.387(8)), C37–C38(1.512(8)). Selected
angles in ꢁ: P1–Ni–P2(105.18(5)), P1–Ni–C45(109.51(14)), P2–Ni–
C45(96.04(14)).
[8] [Ni(dippe)(g3-allyl)(CN–BPh3)], [17a] and [Ni(dippe)-
(g3-allyl)(CN)], [17b] which are described as square-pyra-
midal at the metal center, with the CN ligand in the apical
position.
Table 2
Summary of crystallographic results for 3
Empirical formula
Formula weight
Temperature (K)
C45H50BFeNNiP2
792.17
273(2)
The bond distances in complex 3 are in agreement with
those found in closely related structures. A noteworthy fea-
ture of the structure is that no substantial effect is observed
due to the LA coordination to the CN moiety. The C–N
˚
Wavelength (A)
0.71073
Triclinic
Crystal system
Space group
ꢀ
P1
3
˚
Unit cell dimensions
distance without LA being 1.173(6) A in [Ni(dppb)(g -
˚
3
a (A)
11.664(2)
12.070(2)
15.918(3)
˚
1Me–C3H4)(CN)], [8] and 1.146(4) A in [Ni(dippe)(g -
˚
b (A)
allyl)(CN)], [17b] while in the case of complex 3 it is
˚
c (A)
˚
1.144(6) A. This distance is also very similar to those
a (ꢁ)
b (ꢁ)
c (ꢁ)
105.857(3)
94.501(4)
107.635(3)
2022.4(7)
reported for [Ni(DPEphos)(g3-1-Me–C3H4)(CN–ZnCl2Æ
3
˚
EtOH)] (1.150(3) A), [10] and [Ni(dippe)(g -allyl)(CN–
3
˚
Volume (A )
˚
BPh3)] (1.1517(19) A) [17a]. None of the NiACN bond
Z
2
distances showed dramatic differences, these being
Density (calculated) (Mg mÀ3
Absorption coefficient (mmÀ1
F(000)
)
)
1.301
0.935
832
˚
1.894 0.001 A in complex 3 and those with DPEphos
[10] and dppb [8] ligands.
Crystal size (mmÀ3
)
0.18 · 0.14 · 0.11
1.35–25.00
À13 6 h 6 13, À14 6 k 6 14,
À18 6 l 6 18
19284
The lack of catalytic activity of compounds 2 and 3 for
isomerization of 2M3BN, is consistent with the ability of
BEt3 and ZnCl2 to stabilize the corresponding allyl com-
plex upon coordination to the cyanide moiety. This coordi-
nation inhibits return of the cyanide to the allyl fragment
for the formation of 3PN.
Theta range for data collection (ꢁ)
Index ranges
Reflections collected
Independent reflections [Rint
Completeness to h = 25.00ꢁ (%)
]
7086 [0.0581]
99.4
Refinement method
Full-matrix least-squares
on F2
3. Conclusions
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I > 2r(I)]
R indices (all data)
7086/0/464
1.256
R1 = 0.0742, wR2 = 0.1627
R1 = 0.0887, wR2 = 0.1695
0.826 and À0.467
The use of both bis-diphenylphosphinoferrocene and
[Ni(COD)2] as catalytic precursors gave improved yields
and reaction times for the catalytic isomerization of
À3
˚
Largest difference peak and hole (e A
)

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A. Acosta-Ramı´rez et al. / Journal of Organometallic Chemistry 691 (2006) 3895–3901
2M3BN to 3PN. Allyl species are involved as intermediates
in the CACN bond cleavage and formation. The use of
Lewis acids decreases the activity of the complexes due to
coordination to the nitrogen in the NiACN moiety, but
allows full X-ray characterization. Further work is under-
way to expand the scope of this reaction with the use of clo-
sely related bis-diphosphinoferrocene ligands.
4.2. Catalytic isomerization of 2M3BN in the presence of LA
A solution of 2M3BN (0.4 mL, 4.00 mmol), BEt3 or
ZnCl2 (0.036 mmol), and dppf (19.9 mg, 0.036 mmol)
was added to yellow crystalline [Ni(COD)2] (10 mg,
0.036 mmol), producing a red solution. The mixture was
transferred to an NMR tube with a J. Youngs valve, and
the tube was heated at 100 ꢁC in an oil bath with stirring.
After cooling to room temperature, a sample was dissolved
in THF inside the dry box, and analyzed by GC–MS. Also
a second sample was dissolved in toluene-d8 and analyzed
4. Experimental
All manipulations were carried out using standard
Schlenk and glove box techniques under argon (Praxair
99.998). THF (J.T. Baker) was dried and distillated from
dark purple solutions of sodium/benzophenone ketyl. Deu-
terated solvents were purchased from Cambridge Isotope
1
by H NMR spectroscopy as described in the text.
4.3. Preparation of [Ni(dppf)(g3-1Me–C3H4)(CN)] (1)
˚
Laboratories and stored over 3 A molecular sieves in an
A solution of dppf (50 mg, 0.09 mmol) in 2 mL of THF
was added dropwise to a stirred solution of [Ni(COD)2]
(25 mg, 0.09 mmol) in 3 mL of THF, giving an orange solu-
tion of [Ni(COD)(dppf)] which was further stirred for
15 min. Nine microliters of 2M3BN (0.09 mmol) were then
added, and after 30 min of stirring a red solution was
obtained. The solvent was then removed in vacuo and
the residue was dried for 3 h to give a red solid (57.3 mg,
MBraun glove box (<1 ppm H2O and O2). [Ni(COD)2]
was purchased from Strem and purified from a THF solu-
tion, filtered through Celite, and vacuum dried to yield yel-
low crystalline [Ni(COD)2], which was further dried for 3 h
in vacuo. BEt3 and dppf were purchased from Aldrich and
were used as received. 2M3BN (86.5% by GC–MS, see
Fig. S-1) was purchased from TCI America, purged and
stored in the glove box. ZnCl2 was purchased from J.T.
Baker and dried in vacuo. 1H, 13C{1H} and 31P{1H}
NMR spectra were recorded at room temperature on a
300 MHz Varian Unity spectrometer in THF-d8, Tolu-
1
92%). H NMR (299.7 MHz): d 4.82 (m, 1H, CH central)
and 4.71 (m, 1H, CH central), 4.19 (m, 1H, CHMe) and
4.15 (m, 1H, CHMe), 2.77(m, 2H, CHH) and 2.66 (m,
2H, CHH), 1.77 (m, 3H, CH3) and 1.68 (m, 3H, CH3),
and 1.55 (m, 2H, CHH) and 1.44 (m, 2H, CHH).
13C{1H} NMR (75.4 MHz): d 145.6 (CN), 112.7 and
111.7 (CH central), 85.3 and 82.7 (CHMe), 48.9 and 47.3
(CH2), and 18.7 and 17.8 (CH3). 31P{1H} NMR
(100 MHz): d 20.6–13.3. FAB+: 667 (M+–CN).
1
ene-d8 or CD2Cl2. H and 13C{1H} chemical shifts (d) are
reported relative to the residual proton resonances in the
deuterated solvent. All 31P{1H} NMR spectra were
recorded relative to external 85% H3PO4. Variable temper-
ature 31P{1H} NMR spectra were recorded on a 400 MHz
Varian Unity. All NMR spectra and catalytic reactions
were carried out using thin wall (internal diameter
0.38 mm) WILMAD NMR tubes with J. Young valves.
A Bruker APEX CCD diffractometer with monochroma-
4.4. Preparation of [Ni(dppf)(g3-1Me–C3H4)(CN–Lewis
acid)]: LA@ZnCl2 (2) and LA@BEt3 (3)
˚
tized Mo Ka radiation (k = 0.71073 A) was used for the
To a stirred solution of 1, prepared as above, 0.09 mmol
of the corresponding LA in 1 mL of THF was added. After
30 min of stirring, an orange solution was obtained. The
solvent was then removed in vacuo and the residue was fur-
ther dried for 3 h, producing 2 as an orange solid (66.4 mg,
89%) or 3 as a red–orange solid (63.5 mg, 89.1%). 1H NMR
for 2 (299.7 MHz): d 5.81 (m, 1H, CH central) and 5.55 (m,
1H, CH central), 3.35 (m, 1H, CHMe) and 3.05 (m, 1H,
X-ray structure determinations. A crystal of 3 was
mounted under Paratone 8277 on a glass fiber and immedi-
ately placed under a cold stream of nitrogen. Mass determi-
nations (FAB+) on a JEOL SX-102 A, using nitrobenzilic
alcohol matrix and GC–MS determinations on a Varian
Saturn 3, on a 30 m DB-5MS capillary column.
3
4.1. Catalytic isomerization of 2M3BN in the absence of LA
CHMe), 2.63 and 2.55 (d, 2H JH–H = 14.1 Hz, CHH),
3
1.63 and 1.61 (d, 2H, JH–H = 13.3 Hz, CHH), and 1.72
3
3
A solution of 2M3BN (0.4 mL, 4.00 mmol) and dppf
(19.9 mg, 0.036 mmol) was added to the yellow crystalline
[Ni(COD)2] (10 mg, 0.036 mmol), producing a red solution.
The mixture was transferred to an NMR tube with a J.
Youngs valve, and the tube was heated at 100 ꢁC in an
oil bath with stirring. After cooling to room temperature,
a sample of the reaction mixture was dissolved in THF
inside the dry box and analyzed by GC–MS. A second
(d, 3H, JH–H = 6.6 Hz, CH3) and 1.4 (d, 3H, JH–H
= 7.2 Hz, CH3). 13C{1H} NMR (75.4 MHz) for 2: d
144 ppm (CN), 88.4 (CH central), 69.6 (CHMe), 51.5
(CH2), and 20.5 (CH3). 31P{1H} for 2 (100 MHz, 25 ꢁC): d
24.5, 23 (bs), 24.5(d) and 23.1(d) (2JP–P = 19.5 Hz).
FAB+: 667 (M+–CN–ZnCl2). 1H NMR for
3
(299.7 MHz): d 4.83 (pq, 1H, CH central), 2.90 (m, 1H,
CHMe), 2.98(m, 1H, CHH), 1.51 (m, 1H, CHH), and
1
3
sample was dissolved in toluene-d8 and analyzed by H
NMR spectroscopy, showing resonances identical to those
of trans-3PN.
1.44 (d, 3H, JH–H = 5.1Hz, CH3), 0.63 (m, 6H, BCH2)
and 0.09 (m, 9H, CH3). 13C{1H} NMR (75.4 MHz) for 3:
d 142.2(CN), 98.4 (CH central), 86.6 (CHMe), 52.2 (CH2),

A. Acosta-Ramı´rez et al. / Journal of Organometallic Chemistry 691 (2006) 3895–3901
3901
and 15.7 (CH3), 20.8 (BCH2) and 11.2 (CH3). 31P{1H}
[6] J.D. Druliner, Organometallics 3 (1984) 205.
[7] J.E. Ba¨ckvall, O.S. Andell, Organometallics 5 (1986) 2350.
[8] A. Chaumonnot, F. Lamy, S. Sabo-Etienne, B. Donnadieu, B.
Chaudret, J.C. Barthelat, J.C. Galland, Organometallics 23 (2004)
3363.
NMR for 3: d 20.9 (br). FAB+: 667 (M+–CN–BEt3).
Acknowledgements
[9] J.I. Van der Vlugt, A.C. Hewat, S. Neto, R. Sablong, A.M. Mills, M.
Lutz, A.L. Spek, C. Muller, D. Vogt, Adv. Synth. Catal. 346 (2004)
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993.
We thank CONACyT (Grant 42467-Q) and DGAPA-
UNAM (Grant IN205603) for the financial support to this
[10] J. Wilting, C. Muller, A.C. Hewat, D.D. Ellis, D.M. Tooke, A.L.
¨
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work. We also thank Dr. Alma Arevalo and M en C. Rosa
Spek, D. Vogt, Organometallics 24 (2005) 13.
Isela del Villar for technical assistance. AA-R also thanks
CONACyT and DGEP-UNAM for graduate studies
Grant. WDJ thanks NSF for a travel grant (NSF
INT0102217).
[11] A. Chamard, J.C. Galland, B. Didillon, Method for transforming
ethylenically unsaturated compounds into nitriles and branched
nitriles into linear nitriles. PAT. WO 03/031392, 2002.
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T. Jungkamp, M. Altmayer, W. Seigel, Catalyst system containing,
Ni(0) for hydrocyanation. US/2004 0176622, 2004;
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Tables of complete crystallographic data for 3. Crystal-
lographic data for the structural analysis has been depos-
ited with the Cambridge Crystallographic Data Centre,
CCDC No. 605934 for compound 3. Supplementary data
associated with this article can be found, in the online ver-
sion, at doi:10.1016/j.jorganchem.2006.05.042.
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