Reaction of (η2-arylaldehyde)nickel(0) complexes with Me3SiX (X=OTf, Cl). Application to catalytic reductive homocoupling reaction of arylaldehyde

Article abstract of DOI:10.1016/j.tet.2006.03.124

Arylaldehydes can coordinate to nickel(0) in η²-fashion to give η²-arylaldehydenickel complexes, which react with Me₃SiOTf or Me₃SiCl to give η¹:η¹-siloxybenzylnickel or η³-silox

Full text of DOI:10.1016/j.tet.2006.03.124

Tetrahedron 62 (2006) 7583–7588
Reaction of (h2-arylaldehyde)nickel(0) complexes with
Me3SiX (X¼OTf, Cl). Application to catalytic
reductive homocoupling reaction of arylaldehyde
*
Sensuke Ogoshi, Hirohumi Kamada and Hideo Kurosawa
Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
Received 21 November 2005; revised 6 March 2006; accepted 6 March 2006
Available online 19 June 2006
Dedicated to Professor G€unther Wilke for his great contribution to the field of organonickel chemistry
Abstract—Arylaldehydes can coordinate to nickel(0) in h2-fashion to give h2-arylaldehydenickel complexes, which react with Me3SiOTf or
Me3SiCl to give h1:h1-siloxybenzylnickel or h3-siloxybenzyl complex. In the presence of PCy3 or CO, h1:h1-siloxybenzylnickel complex
underwent homocoupling reaction to give a pinacol type product. In the presence of zinc dust, the reductive homocoupling reaction of
arylaldehyde proceeded catalytically to form pinacol derivatives in 70–99% yield. On the other hand, h3-siloxybenzylnickel complex regen-
erated benzaldehyde and Me3SiOTf under a carbon monoxide pressure.
Ó 2006 Elsevier Ltd. All rights reserved.
1. Introduction
However, the reactivity and its application to catalytic reac-
tions have not been studied yet. Here, we report the synthesis
and reactivity of both h3-siloxyarylmethylnickel and h1:h1-
siloxybenzylnickel complexes generated by the reaction
of h2-aldehyde complex of nickel(0) with Me3SiOTf or
Me3SiCl. The carbon–carbon bond formation by the homo-
coupling reactions of these complexes and its application
to a catalytic reaction in the presence of zinc dust are also
reported.
The transformation of carbonyl compounds by transition
metal catalysts is one of the very efficient methods to intro-
duce oxygen into an organic molecule. However, only scat-
tered studies on the reaction of carbonyl compounds
coordinated to late transition metals have been reported.
So far, we have reported the reaction of a,b-unsaturated car-
bonyl compounds coordinated to palladium or platinum
in h2-fashion with Lewis acids or electrophiles to give the
corresponding h3-allyl complexes having oxygen containing
substituent at the allyl terminal carbon (Schemes 1 and 2).1
As the hapticity of the enone coordination changes from
h2 to h3, the carbonyl carbon–metal covalent bond is formed
by the electron donation from palladium or platinum to car-
bonyl carbon, which is confirmed by the theoretical study.1a
These results suggest that larger electron donating ability of
the metal center is favorable for the formation of a covalent
bond between a carbonyl carbon and a transition metal cen-
ter. We thought h2-coordination of carbonyl group to an
electron rich transition metal center is one of the ideal situa-
tions for the formation of carbon–metal covalent bond by
the addition of electrophiles. Although the coordination of
aldehydes or ketones in h2-mode is very rare for the late
transition metals, several h2-aldehyde and h2-ketone com-
plexes of nickel have been reported.2,3 Moreover, recently,
we reported the reaction of h2-aldehyde complexes with
Me3SiOTf to give h1:h1-siloxymethylnickel complexes.4
LA-
O
O
LA
M+
M
LA = Lewis Acid
Scheme 1.
R
O
O
M+
ROTf
M
-
OTf
R = SiMe3, Me, H
Scheme 2.
2. Results and discussion
h2-Arylaldehydenickel complexes (1a–1d) were prepared
conveniently in quantitative yield by the reaction of the cor-
responding arylaldehyde with Ni(cod)2 and PCy3 or DPPF
* Corresponding author. E-mail: ogoshi@chem.eng.osaka-u.ac.jp
0040–4020/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2006.03.124

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S. Ogoshi et al. / Tetrahedron 62 (2006) 7583–7588
(Scheme 3). The X-ray structure analysis on 1a reported by
Walther showed h2-coordination of benzaldehyde.2 The for-
myl hydrogen and carbon in arylaldehyde coordinated to
nickel are found far upfield in 1H and 13C NMR spectra com-
pared to those of free arylaldehyde; ArCHO in 1a–1d is at
ca. d 6.0–6.7 (d 9.6–10.0 for free) and ArCHO is at ca.
d 80–90 (d 180–190 for free), which are consistent with
the h2-coordination of an arylaldehyde to a nickel(0) and
the strong back donation from the nickel(0) center to the
carbonyl group even in a solution.
of the proposed intermediate in palladium/Me3SiOTf-
catalyzed bis-silylation of arylaldehyde.1b At this moment,
we cannot rationalize the different reactivities toward
Me3SiOTf between 1a and 1c clearly. However, it may well
account for a part of this observation that h3-coordination
of the benzyl ligand may require the softer nature of the
nickel center than its h1-coordination, and this requirement
would be better fulfilled by the coordination of more the
phosphorus ligands. A similar observation in the equilibrium
between h3-allenyl/propargylpalladium and h1-propargyl-
palladium had been reported.5 h3-Siloxymethylarylnickel
complex 2d reacted with H2O to give desilylated complex
4d (Scheme 7). The X-ray structure analysis on 4d shows
h3-coordination of hydroxymethylnaphthyl moiety. This
complex was also formed by the reaction of 1d with TfOH
very rapidly and quantitatively. A similar reaction, the reac-
tion of h2-enonepalladium or platinum with TfOH to giveh3-
1-hydroxyallylpalladium or platinum, had been reported.1c
O
O
O
P
O
P
H
H
H
H
Ni
Ni
Ni
Ni
Cy3P
Cy3P
P
P
PCy3
PCy3
1a
1b
1c
1d
Scheme 3.
H
The reaction of (h2-PhCHO)Ni(PCy3)2 (1a) with Me3SiOTf
gave the corresponding h1:h1-siloxybenzylnickel complex
(2a) (Scheme 4).4 Similarly, the reaction with Me3SiCl
gave the chloride analog (3a). Both resonances of benzyl
Me3SiX
1b
OSiMe3
Ni
Cy3P
X
3b: X = Cl
1
proton and carbon in H and 13C NMR of 3a are found in
Scheme 5.
higher magnetic field than those for 1a and were coupled
with phosphorus. On the other hand, those of phenyl group
are little different from the corresponding resonances of 1a
and free PhCHO in 1H and 13C NMR spectra. These spectral
trends are similar to those of 2a.
H
H
P +
OSiMe3
P +
Ni
Ni
OSiMe3
OTf-
P
OTf-
P
2d
2c
OSiMe3
H
Me3SiX
Scheme 6.
1a
Ni
Cy3P
X
2a: X = OTf
3a: X = Cl
TfOH
H2O
H
1d
2d
P+
Ni
Scheme 4.
OH
P
OTf-
The reaction of (h2-(1-NaphCHO))Ni(PCy3)2 (1b) with
Me3SiCl proceeded very rapidly to give (h3-1-
Me3SiOCHC10H7)Ni(PCy3)(Cl) (3b) quantitatively (Scheme
5), although 1a was transformed into h1:h1-siloxybenzyl-
nickel under the same condition. The corresponding com-
plex having OTf (2b) was generated from 1b and
Me3SiOTf, but could not be isolated due to the decomposi-
tion in the solution. In the spectra of 3b, both proton and
carbon at ipso- and b-position of naphthalene ring and
Me3SiOCH- were observed in much higher magnetic field
than those in the spectra of 1b, which indicates that these
two carbons of aromatic ring participates in the coordination
to nickel. The difference in the coordination mode between
2a, 3a, and 3b might be due to the difference in the number
of fused benzene ring. Thus, one benzene ring can remain
intact on going from 1b to 3b, while 1a has to lose all of
its aromaticity upon forming the corresponding h3-siloxy-
benzylnickel complex. The treatment of 1c or 1d with
Me3SiOTf led to the corresponding cationic h3-siloxy-
methylarylnickel complexes (2c, 2d), which also show
higher magnetic field shift of proton and carbon at ipso-
and b-position of naphthalene ring and Me3SiOCH–
(Scheme 6). These complexes could be the nickel analogs
4d
Scheme 7.
The addition of PCy3 to a solution of 2a or 3a led to the for-
mation of 1,2-bis(trimethylsiloxy)-1,2-diphenylethane (5a)6
in 78 or 48% yield concomitant with an unidentified product,
probably nickel(I) complex (Scheme 8). Similarly, the treat-
ment of 3a with carbon monoxide (5 atm) led to the forma-
tion of 5a in 63%. This reaction might have proceeded via
neutral nickel(II) intermediate as shown in Scheme 8, in
which a radical coupling reaction might be involved. On the
other hand, 2c underwent the regeneration of PhCHO and
Me3SiOTf concomitant with the formation of Ni(CO)2-
(DPPF) under the same condition (Scheme 9). The reaction
might have proceeded via cationic h1- or five-coordinated
h3-benzylnickel(II) species generated by the coordination
of carbon monoxide to nickel(II) center followed by the
nucleophilic attack of TfOꢀ at Me3Si group. Similarly, the re-
action of 2c with nBu4NCl generated (h2-PhCHO)Ni(DPPF)
(1c) and Me3SiCl rapidly by the nucleophilic attack of
Clꢀ at Me3Si group. The (h2-PhCHO)Ni(DPPF) thus
generated reacted with Me3SiCl slowly in situ to give 5a in

S. Ogoshi et al. / Tetrahedron 62 (2006) 7583–7588
7585
51% yield. In fact, the reaction of 1c with Me3SiCl gave 5a as
a sole organic product in 66% yield in C6D6 or quantitatively
in THF.
4. Conclusion
The reaction of (h2-PhCHO)Ni(PCy3)2 with Me3SiOTf
or Me3SiCl gave neutral h1:h1-siloxybenzylnickel complex.
This complex underwent the homocoupling reaction to give
a pinacol derivative in the presence of PCy3 or CO. The
reaction of (h2-NaphCHO)Ni(PCy3)2 with Me3SiCl gave a
neutral h3-siloxynaphthylmethylnickel complex. Both (h2-
PhCHO)Ni(DPPF) and (h2-NaphCHO)Ni(DPPF) reacted
with Me3SiOTf to give cationic h3-siloxyarylmethylnickel
complexes. The reaction of (h2-PhCHO)Ni(DPPF) with
Me3SiCl gave the pinacol derivative and a nickel(I) species.
In the presence of Zn dust, the reaction proceeded catalyti-
cally by the reduction of the nickel(I) to nickel(0).
2a
PCy3 or CO
or
C6D6
3a
OSiMe3
X
Ni
Me3SiO
+
H
"L1L2NiX"
OSiMe3
5a
Me3SiCl
L1
L2
1c
C6D6 or THF
L1, L2 = PCy3, X = OTf, Cl
L1 = PCy3 L2 = CO, X = Cl
L1, L2 = DPPF, X = Cl
Scheme 8.
O
H
5. Experimental
5.1. General
OSiMe3
CO
CO
H
Me3SiOTf
2c
+
+
C6D6
H
or
+Ni
P
OSiMe3
CO
Ni
P
+
-
Ni(CO) (DPPF)
2
OTf
P
P
-
OTf
All manipulations were conducted under a nitrogen atmo-
sphere using standard Schlenk or dry box techniques. H,
1
Scheme 9.
31P, and 13C nuclear magnetic resonance spectra were
recorded on JEOL GSX-270S and JEOL AL-400 spectro-
meters. The chemical shifts in H nuclear magnetic reso-
3. Catalytic reaction
1
The stoichiometric reaction of 1c with Me3SiCl depicted in
Scheme 8 prompted us to test a possibility of a catalytic for-
mation of 5a and analogs by combining Scheme 8 with the
reduction of L1L2NiX to Ni(0) species.7 In the presence of
10 mol % of Ni(cod)2 and DPPF or the corresponding (h2-
arylaldehyde)Ni(DPPF) and zinc dust as a reductant, the
homocoupling reaction of arylaldehyde moiety proceeded
catalytically to give pinacol type products as a mixture of
two diastereomers (threo/erythro¼50/50 for all products)
(Scheme 10). The results are summarized in Scheme 11.
Yields are determined for the diol compounds obtained
by the hydrolysis of silylether.7,8 The substituent group
on phenyl group does not affect the yield so much (4-
MeOC6H4CHO (73%), PhCHO (88%), 4-CF3C6H4CHO
(99%)). This reaction can be applied to naphthaldehydes
as well (1-NaphCHO (70%), 2-NaphCHO (91%)).
nance spectra were recorded relative to Me4Si or residual
protonated solvent (C6D5H (d 7.16), CDHCl2 (d 5.32)).
The chemical shifts in the 13C spectra were recorded relative
to Me4Si. The chemical shifts in the 31P spectra were
recorded using 85% H3PO4 as an external standard. Assign-
1
ment of the resonances in H and 13C NMR spectra was
1
based on H–1H COSY, HMQC, and HMBC experiments.
HMQC and HMBC experiments are inverse detection hetero-
correlated NMR experiments recorded at the H frequency
1
of the spectrometer, probing one-bond (CH) and multiple-
bond (CCH and CCCH) connectivity. Elemental analyses
were performed at Instrumental Analysis Center, Faculty
of Engineering, Osaka University. For some compounds,
accurate elemental analyses were precluded by extreme air
or thermal sensitivity and/or systematic problems with
elemental analysis of organometallic compounds. X-ray
crystal data were collected by using a Rigaku RAXIS-
RAPID Imaging Plate diffractometer.
Me3SiO
Ar
Ar
O
10 mol% Ni(0)
+
Me3SiCl
Zn dust
+
Ar
H
OSiMe3
Zn dust
5.2. Materials
"L2NiX"
Ni(0)
Me3SiCl
Ar
H
OSiMe3
The degassed and distilled solvents (THF, toluene, and hex-
ane) used in this work were commercially available. C6D6
was distilled from sodium benzophenone ketyl. All commer-
cially available reagents were distilled and degassed prior to
use.
X
Ni
L
L
Scheme 10.
OMe
CF3
OSiMe3
OSiMe3
OSiMe3
OSiMe3
OSiMe3
Me3SiO
Me3SiO
Me3SiO
Me3SiO
Me3SiO
OMe
CF3
5a: 88%
5b: 73%
5c: 99%
5d: 70%
5e: 91%
Scheme 11.

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S. Ogoshi et al. / Tetrahedron 62 (2006) 7583–7588
5.2.1. Isolation of (h2-(1-NaphCHO))Ni(PCy3)2 (1b). To
a solution of Ni(cod)2 (177 mg, 0.64 mmol) and PCy3
(362 mg, 0.64 mmol) in 5 mL of toluene was added 88 mL
of 1-naphthaldehyde (101 mg, 1.28 mmol) at room tempera-
ture. The reaction mixture was concentrated in vacuo to give
145 mL of Me3SiOTf (178 mg, 0.80 mmol) at room tempera-
ture. The solution changed from orange to dark purple
immediately. The reaction mixture was filtered through
a short Celite column followed by concentration in vacuo
1
to give 2a (368 mg, purple solids) in 69% yield. H NMR
1
1b (450 mg, dark purple solids) in 95% yield. H NMR
(400 MHz, C6D6, 25 ꢁC): d 0.31 (s, 9H, –SiMe3),
0.95–1.95 (m, 33H, Cy), 4.34 (d, J¼3.5 Hz, 1H, –CHO-
SiMe3), 7.02 (d, J¼7.3, 7.4 Hz, 2H, m-Ph), 7.13 (t,
J¼7.4 Hz, 1H, p-Ph), 7.47 (d, JHP¼7.3 Hz, 2H, o-Ph). 31P
NMR (109 MHz, C6D6, 25 ꢁC): d 42.0 (s). 13C NMR
(100 MHz, C6D6, 25 ꢁC): d 0.5 (s, –SiMe3), 27.1 (s, Cy),
28.4 (q, JCP¼9.9 Hz, Cy), 30.6 (d, JCP¼30.7 Hz, Cy), 33.6
(d, JCP¼21.5 Hz, Cy), 62.3 (d, JCP¼11.4 Hz, –CHOSiMe3),
124.0 (s, o-Ph), 127.9 (s, p-Ph), 130.3 (s, m-Ph), 140.9 (s,
ipso-Ph). Anal. Calcd for C29H48F3Ni1O4P1S1Si1(H2O): C,
52.18; H, 7.25. Found: C, 50.98; H, 6.71.
(400 MHz, C6D6, 25 ꢁC): d 0.83–2.29 (m, 66H, Cy), 6.40
(t, J¼5.0 Hz, 1H, –CHO), 7.27 (dd, J¼7.2, 7.6 Hz, 1H,
7-Ar), 7.39 (dd, J¼7.2, 8.7 Hz, 1H, 8-Ar), 7.44 (dd, J¼6.9,
8.0 Hz, 1H, 3-Ar), 7.67 (d, J¼8.0 Hz, 1H, 4-Ar), 7.75 (d,
J¼7.6 Hz, 1H, 6-Ar), 8.29 (d, J¼6.9 Hz, 1H, 2-Ar), 8.81
(d, J¼8.7 Hz, 1H, 9-Ar). 31P NMR (109 MHz, C6D6,
25 ꢁC): d 36.75 (d, JPP¼43.3 Hz), 45.13 (d, JPP¼43.3 Hz).
13C NMR (100 MHz, C6D6, 25 ꢁC): d 27.02–36.85 (Cy),
75.75 (d, JCP¼16.7 Hz, –CHO), 121.56 (d, JCP¼4.6 Hz,
2-Ar), 123.57 (d, JCP¼3.0 Hz, 4-Ar), 124.12 (s, 7-Ar),
125.03 (s, 8-Ar), 125.36 (s, 6-Ar), 126.72 (d, JCP¼3.0 Hz,
3-Ar), 128.63 (s, 5-Ar), 131.26 (d, JCP¼2.3 Hz, 9-Ar),
135.42 (s, 10-Ar), 147.47 (d, JCP¼4.6 Hz, 1-Ar). Anal. Calcd
for C47H74O1P2Ni1: C, 72.77; H, 9.62. Found: C, 72.98;
H, 9.50.
5.2.5. Isolation of (h1:h1-Me3SiOCHC6H5)Ni(PCy3)(Cl)
(3a). To a solution of Ni(cod)2 (220 mg, 0.80 mmol), PCy3
(224 mg, 0.80 mmol), and 81.3 mL of PhCHO (84.8 mg,
0.80 mmol) in 7 mL of THF was added 101 mL of Me3SiCl
(86.9 mg, 0.80 mmol) at room temperature. The solution
changed from orange to dark purple immediately. The reac-
tion mixture was filtered through a short Celite column fol-
lowed by concentration in vacuo to give 3a (297 mg, purple
5.2.2. Isolation of (h2-PhCHO)Ni(DPPF) (1c). To a solu-
tion of Ni(cod)2 (383 mg, 1.39 mmol) and DPPF (771 mg,
1.39 mmol) in 10 mL of toluene was added PhCHO
(178 mg, 1.67 mmol) at room temperature. The solution
changed from yellow to orange. The reaction mixture was
concentrated in vacuo to give orange solids quantitatively.
The solids were washed with hexane to give 1c (988.7 mg,
1
solids) in 67% yield. H NMR (270 MHz, C6D6, 25 ꢁC):
d 0.41 (s, 9H, –SiMe3), 0.89–2.20 (m, 33H, Cy), 4.54
(d, J¼3.2 Hz, 1H, –CHOSiMe3), 7.03 (m, 3H), 7.49 (d,
31
J¼6.5 Hz, 2H). P NMR (109 MHz, C6D6, 25 ꢁC): d 46.4
1
13
orange solids) in 99% yield. H NMR (400 MHz, C6D6,
(s). C NMR (67.5 MHz, C6D6, 25 ꢁC): d 0.6 (s, –SiMe3),
25 ꢁC): d 3.82–4.32 (m, 8H, Cp), 6.00 (t, J¼6.1 Hz, 1H,
–CHO), 7.28–7.35 (m, 15H), 7.28–7.35 (m, 2H), 7.48 (d,
J¼6.8 Hz, 2H), 7.85 (m, 2H), 8.30 (m, 4H). 31P NMR
(109 MHz, C6D6, 25 ꢁC): d 20.60 (d, JPP¼36.6 Hz), 32.20
27.2 (s, Cy), 28.3 (q, JCP¼5.5 Hz, Cy), 30.4 (d,
JCP¼17.6 Hz, Cy), 34.1 (d, JCP¼21.6 Hz, Cy), 63.6 (d,
JCP¼11.5 Hz, –CHOSiMe3), 124.1 (s), 126.6 (s), 129.7 (s),
143.2 (s). Anal. Calcd for C28H48Cl1Ni1O1P1Si1: C, 60.72;
H, 8.73. Found: C, 61.00; H, 8.51.
13
(d, JPP¼36.6 Hz). C NMR (100 MHz, C6D6, 25 ꢁC):
d 71.38–86.40 (Cp), 86.48 (d, JCP¼16.7 Hz, –CHO),
124.37–137.49 (Ph-CHO), 148.95 (d, JCP¼4.6 Hz, ipso-
Ph-CHO). Anal. Calcd for C41H34O1P2Fe1Ni1: C, 68.47;
H, 4.77. Found: C, 67.48; H, 4.67.
5.2.6. Isolation of (h3-1-Me3SiOCHC10H7)Ni(PCy3)(Cl)
(3b). To a solution of Ni(cod)2 (271 mg, 1.0 mmol), PCy3
(280 mg, 1.0 mmol), and 136 mL of 1-naphthaldehyde
(156 mg, 1.0 mmol) in 5 mL of THF was added 127 mL of
Me3SiCl (108 mg, 0.80 mmol) at room temperature. The solu-
tion changed from orange to deep red. The reaction mixture
was filtered through a short Celite column and reprecipitation
from THF/pentane afforded3b (383 mg, brown solids) in 63%
yield. 1H NMR (400 MHz, toluene-d8, ꢀ30 ꢁC): d 0.07 (s, 9H,
–SiMe3), 1.14–1.92 (m, 33H, Cy), 5.86 (d, J¼8.0 Hz, 1H,
–CHOSiMe3), 6.58 (br s, 1H, 2-Ar), 7.29 (dd, J¼7.4, 7.6 Hz,
1H, 7-Ar), 7.36 (dd, J¼7.4, 8.0 Hz, 1H, 8-Ar), 7.48 (d,
J¼7.6 Hz, 1H, 6-Ar), 7.51 (dd, J¼6.5, 8.7 Hz, 1H, 3-Ar),
7.62 (d, J¼8.7 Hz, 1H, 4-Ar), 7.70 (d, J¼8.0 Hz, 1H, 9-Ar).
31P NMR (160 MHz, toluene-d8, ꢀ30 ꢁC): d 37.1 (s). 13C
NMR (100 MHz, toluene-d8, ꢀ30 ꢁC): d 0.10 (s, –SiMe3),
14.9–35.0 (Cy), 69.7 (s, –CHOSiMe3), 92.4 (s, 2-Ar), 108.6
(s, 1-Ar), 122.4 (s, 8-Ar), 126.7 (s, 9-Ar), 126.9 (s, 7-Ar),
127.60 (6-Ar, hidden by toluene-d8), 127.85 (4-Ar, hidden
by toluene-d8), 129.9 (s, 5-Ar), 133.3 (s, 3-Ar), 136.1 (s,
10-Ar). Anal. Calcd for C32H50Cl1Ni1O1P1Si1: C, 63.64;
H, 8.34. Found: C, 63.43; H, 8.35.
5.2.3. Isolation of (h2-(1-NaphCHO))Ni(DPPF) (1d). To
a solution of Ni(cod)2 (179 mg, 0.65 mmol) and DPPF
(360 mg, 0.65 mmol) in 5 mL of toluene was added 1-naph-
thaldehyde (102 mg, 0.65 mmol) at room temperature. The
reaction mixture was concentrated in vacuo to give orange
solids quantitatively. The solids were washed with hexane
to give 1d (479.2 mg, orange solids) in 96% yield. 1H
NMR (400 MHz, C6D6, 25 ꢁC): d 3.70–4.25 (m, 8H, Cp),
6.58 (br s, 2H), 6.70 (s, 2H including –CHO), 6.91 (t,
J¼7.1 Hz, 2H), 7.10–7.20 (m, 12H), 7.52 (d, J¼8.1 Hz,
1H), 7.58 (d, J¼8.1 Hz, 1H), 7.83 (br s, 2H), 7.96 (d,
J¼6.2 Hz, 1H), 8.24 (br s, 4H), 8.53 (d, J¼8.4 Hz, 1H).
31P NMR (109 MHz, C6D6, 25 ꢁC): d 20.83 (d, JPP¼
35.4 Hz), 31.34 (d, JPP¼34.2 Hz). 13C NMR (100 MHz,
C6D6, 25 ꢁC): d 70.70–74.39 (Cp), 85.99 (d, JCP¼16.5 Hz,
–CHO), 122.20–135.20 (Ph), 144.61 (d, JCP¼5.5 Hz).
Anal. Calcd for C45H36O1P2Fe1Ni1: C, 70.26; H, 4.72.
Found: C, 69.73; H, 4.65.
5.2.4. Isolation of (h1:h1-Me3SiOCHC6H5)Ni(PCy3)-
(OTf) (2a). To a solution of Ni(cod)2 (220 mg,
0.80 mmol), PCy3 (224 mg, 0.80 mmol), and 81.3 mL of
PhCHO (84.8 mg, 0.80 mmol) in 7 mL of THF was added
5.2.7. Isolation of [(h3-Me3SiOCHC6H5)Ni(DPPF)][OTf]
(2c). To a suspension of (h2-PhCHO)Ni(DPPF) (1c) (381 mg,
0.53 mmol) in 5 mL of THF was added 96 mL of Me3SiOTf
(118 mg, 0.53 mmol) at room temperature. The orange

S. Ogoshi et al. / Tetrahedron 62 (2006) 7583–7588
7587
suspension changed to deep red solution. The reaction mixture
was concentrated in vacuo. The residue was washed with hex-
ane to give 2c (492.7 mg, orange solids) in 99% yield. H
131.52 (s), 133.93 (s), 135.66 (s), 137.06–145.51 (Ph).
Anal. Calcd for C48H41O4F3P2S1Fe1Ni1(C6H6): C, 62.62;
H, 4.35. Found: C, 63.18; H, 4.35. X-ray data for 4d: M¼
1
NMR (400 MHz, CD2Cl2, 25 ꢁC): d ꢀ0.11 (s, 9H, –SiMe3),
4.16–4.42 (m, 8H, Cp), 4.95 (s, 1H, –CHOSiMe3), 6.65 (d, J¼
7.2 Hz, 2H, o-Ph), 6.97 (d, J¼7.4 Hz, 2H, m-Ph), 7.12 (d, J¼
6.5 Hz, 1H, p-Ph), 7.40–7.70 (m, 20H). 31P NMR (160 MHz,
CD2Cl2, ꢀ80 ꢁC): d 22.66 (d, JPP¼2.4 Hz), 27.20 (s). 13C
NMR (100 MHz, CD2Cl2, 25 ꢁC): d ꢀ0.35 (s, –SiMe3),
74.03–75.68 (m, Cp), 86.16 (t, JCP¼11.4 Hz, –CHOSiMe3),
113.37 (s, o-PhCHOSiMe3), 116.67 (s, ipso-PhCHOSiMe3),
129.51–134.24 (Ph). Anal. Calcd for C45H43O4F3P2S1-
Si1Fe1Ni1: C, 57.41; H, 4.60. Found: C, 57.46; H, 4.74.
1077.59, brown, triclinic, P-1 (no.2), a¼12.448(1) A, b¼
˚
ꢁ
ꢁ
˚
˚
13.753(1) A, c¼16.815(1) A, a¼103.833(4) , b¼105.947(3) ,
g¼104.314(2) , V¼2532.2(4) A , Z¼2, Dcalcd¼1.413 g/cm3,
3
ꢁ
˚
T¼0 ꢁC, R¼0.077.
5.2.12. Generation of [(h3-1-HOCHC10H7)Ni(DPPF)]-
[OTf] (4d). To a suspension of (h2-(1-NaphCHO))Ni(DPPF)
1d (11.5 mg, 0.015 mmol) in 0.5 mL of C6D6 was added
Me3SiOTf (3.3 mg, 0.015 mmol) at room temperature. The
orange suspension changed to deep red solution and 2d was
generated quantitatively. To the solution was added 0.5 mg
of H2O (0.028 mmol, 0.5 mL) to give 4d quantitatively.
5.2.8. Generation of [(h3-Me3SiOCHC6H5)Ni(DPPF)]-
[OTf] (2c). To a solution of 1c (14.4 mg, 0.020 mmol)
in 0.5 mL of CD2Cl2 was added Me3SiOTf (4.4 mg,
0.020 mmol) at room temperature. The solution changed
from orange to deep red and 2c was generated quantitatively.
5.2.13. Reaction of (h1:h1-Me3SiOCHC6H5)Ni(PCy3)-
(OTf) (2a) with PCy3. To a solution of 2a (13.4 mg,
0.02 mmol) in 0.5 mL of C6D6 was added PCy3 (5.8 mg,
0.02 mmol) at room temperature and the reaction mixture
was stirred for 2 days. The pinacol type product (5a) was
generated in 78% yield.
5.2.9. Isolation of [(h3-1-Me3SiOCHC10H7)Ni(DPPF)]-
[OTf] (2d). To a solution of (h2-(1-NaphCHO))Ni(DPPF)
(1d) (155.2 mg, 0.20 mmol) in 10 mL of toluene was added
37 mL of Me3SiOTf (44.8 mg, 0.20 mmol) at room tempera-
ture. The solution changed from orange to deep red solution.
The reaction mixture was filtered through a short Celite
column followed by concentration in vacuo. The residue
was washed with hexane to give 2d (192.4 mg, orange solids)
5.2.14. Reaction of (h1:h1-Me3SiOCHC6H5)Ni(PCy3)-
(Cl) (3a) with PCy3. To a solution of 3a (11.6 mg,
0.02 mmol) in 0.5 mL of C6D6 was added PCy3 (5.6 mg,
0.02 mmol) at room temperature and the reaction mixture
was stirred for 2 days. Compound 5a was obtained in 48%
yield.
1
in 96% yield. H NMR (400 MHz, CD2Cl2, ꢀ20 ꢁC):
d ꢀ0.02 (s, 9H, –SiMe3), 4.00–4.50 (m, 8H, Cp), 5.28 (dd,
JHH¼5.4 Hz, JHP¼9.8 Hz, 1H, 2-Ar), 6.20 (dd, J¼5.4,
7.9 Hz, 1H, 3-Ar), 6.44 (dd, JHP¼2.9, 10.8 Hz, 1H, –CHO-
SiMe3), 6.74 (d, J¼8.3 Hz, 1H, 9-Ar), 6.80 (dd, J¼7.6,
10.8 Hz, 2H), 7.23–7.90 (m, 22H). 31P NMR (160 MHz,
CD2Cl2, ꢀ20 ꢁC): d 24.24 (d, JPP¼10.3 Hz), 26.81 (d,
5.2.15. Reaction of (h1:h1-Me3SiOCHC6H5)Ni(PCy3)-
(Cl) (3a) with CO. A solution of 3a (11.6 mg, 0.02 mmol)
in 0.5 mL of C6D6 in a pressure tight NMR tube was treated
with CO (5 atm). The solution changed from dark purple to
pale blue immediately to give 5a (63%).
13
JPP¼10.3 Hz). C NMR (100 MHz, CD2Cl2, ꢀ20 ꢁC):
d ꢀ0.42 (s, –SiMe3), 73.18–75.25 (m, Cp), 83.46 (d,
JCP¼11.4 Hz, 2-Ar), 94.84 (dd, JCP¼1.5, 17.5 Hz, –CHO-
SiMe3), 105.95 (s, 1-Ar), 121.61 (s, 9-Ar), 124.17 (s, 10-
Ar), 126.15 (s), 126.6 (s), 128.5 (s), 128.82 (d, JCP¼3.8 Hz,
3-Ar), 129.17–134.71. Anal. Calcd for C45H43O4F3P2S1Si1-
Fe1Ni1: C, 59.36; H, 4.57. Found: C, 59.70; H, 5.12.
5.2.16. Reaction of (h1:h1-Me3SiOCHC6H5)Ni(PCy3)-
(OTf) (2a) with CO. A solution of 2a (11.6 mg,
0.02 mmol) in 0.5 mL of C6D6 in a pressure tight NMR
tube was treated with CO (5 atm). The solution changed
from dark purple to colorless solution immediately to give
Ni(PCy3)(CO)3, PhCHO, and Me3SiOTf quantitatively.
5.2.10. Generation of [(h3-1-Me3SiOCHC10H7)Ni(DPPF)]-
[OTf] (2d). To a suspension of 1d (11.5 mg, 0.015 mmol) in
0.5 mL of C6D6 was added Me3SiOTf (3.3 mg, 0.15 mmol)
at room temperature. The orange suspension changed to
deep red solution and 2d was generated quantitatively.
5.2.17. Reaction of [(h3-Me3SiOCHC6H5)Ni(DPPF)][OTf]
(2c) with CO. A solution of 2c (18.9 mg, 0.02 mmol) in
0.5 mL of C6D6 in a pressure tight NMR tube was treated
with CO (5 atm). The solution changed from deep red
to colorless solution immediately to give Ni(DPPF)(CO)2,
PhCHO, and Me3SiOTf quantitatively.
5.2.11. Isolation of [(h3-1-HOCHC10H7)Ni(DPPF)][OTf]
(4d). To a solution of (h2-(1-NaphCHO))Ni(DPPF) (1d)
(167.4 mg, 0.22 mmol) in 10 mL of toluene was added
19 mL of HOTf (32.6 mg, 0.22 mmol) at room temperature.
The orange solution changed to deep red suspension. The
reaction mixture was concentrated in vacuo to give orange
solids. The solids were washed with hexane to give 4d
(186.2 mg, orange solids) in 93% yield. 1H NMR
(400 MHz, CD2Cl2, ꢀ30 ꢁC): d 3.84–4.63 (m, 8H, Cp),
5.32 (1H, –CHOH, hidden by CD2Cl2), 6.38 (s, 1H), 6.49
(s, 1H), 7.12–8.30 (m), 9.34 (s, 1H). 31P NMR (109 MHz,
CD2Cl2, ꢀ80 ꢁC): d 25.63 (d, JPP¼5.0 Hz), 26.07 (d,
5.2.18. Reaction of [(h3-Me3SiOCHC6H5)Ni(DPPF)][OTf]
(2c) with Bu4NCl. To a solution of 2c (18.9 mg, 0.02 mmol)
in 0.5 mL of C6D6 was added Bu4NCl (5.4 mg, 0.02 mmol)
at room temperature and the reaction mixture was stirred for
2 days. Compound 5a was obtained in 51% yield.
5.2.19. Reaction of (h2-PhCHO)Ni(DPPF) (1c) with
Me3SiCl. To a solution of 1c (14.5 mg, 0.02 mmol) in
0.5 mL of C6D6 was added 2.5 mL of Me3SiCl (2.3 mg,
0.02 mmol) at room temperature, and the reaction mixture
was stirred for 2 days. Pinacol type product was obtained
in 66% yield. When the reaction was carried out in THF,
5a was obtained quantitatively.
13
JPP¼5.0 Hz). C NMR (100 MHz, CD2Cl2, ꢀ40 ꢁC):
d 82.32–85.81 (Cp), 87.60 (br s), 110.49 (s), 113.02 (br s),

7588
S. Ogoshi et al. / Tetrahedron 62 (2006) 7583–7588
5.2.20. Typical procedure for catalytic reaction (PhCHO).
Under a nitrogen atmosphere, to a suspension of (h2-
PhCHO)Ni(DPPF) (1.5 mg, 0.002 mmol) and zinc dust
(1.2 mg, 0.020 mmol) in 0.5 mL of THF were added
1.8 mL of PhCHO (2.0 mg, 0.018 mmol) and 2.5 mL of
Me3SiCl (2.3 mg, 0.020 mmol) at room temperature. The
reaction mixture was stirred for 1 day to give 5a in 88%
yield. The yield was determined by GC as the corresponding
diol obtained by the hydrolysis.
References and notes
1. (a) Ogoshi, S.; Yoshida, T.; Nishida, T.; Morita, M.; Kurosawa,
H. J. Am. Chem. Soc. 2001, 123, 1944–1950; (b) Ogoshi, S.;
Tomiyasu, S.; Morita, M.; Kurosawa, H. J. Am. Chem. Soc.
2002, 124, 11598–11599; (c) Ogoshi, S.; Morita, M.;
Kurosawa, H. J. Am. Chem. Soc. 2003, 125, 9020–9021; (d)
Morita, M.; Inoue, K.; Ogoshi, S.; Kurosawa, H. Organometal-
lics 2003, 22, 5468–5472; (e) Morita, M.; Inoue, K.; Yoshida, T.;
Ogoshi, S.; Kurosawa, H. J. Organomet. Chem. 2004, 689,
894–898.
2. Walther, D. J. Organomet. Chem. 1980, 190, 393–401.
3. Bennett, M. A. Pure Appl. Chem. 1989, 61, 1695–1700; Kim,
Y.-J.; Osakada, K.; Yamamoto, A. Bull. Chem. Soc. Jpn. 1989,
62, 964–966; Ashley-Smith, J.; Green, M.; Stone, F. G. A.
J. Chem. Soc. A 1969, 3019–3023.
5.2.21. Reaction of 4-MeOC6H4CHO. Ni(cod)2 (10 mol %)
and DPPF were employed as a catalyst. Compound 5b was
obtained in 73% yield.
5.2.22. Reaction of 4-CF3C6H4CHO. Ni(cod)2 (10 mol %)
and DPPF were employed as a catalyst. Compound 5c was
obtained in 99% yield.
4. Ogoshi, S.; Oka, M.; Kurosawa, H. J. Am. Chem. Soc. 2004, 126,
11082–11083.
5.2.23. Reaction of 1-naphthaldehyde. Compound 2d
(10 mol %) was employed as a catalyst. Compound 5d was
obtained in 70% yield.
5. Tsutsumi, K.; Ogoshi, S.; Nishiguchi, S.; Kurosawa, H. J. Am.
Chem. Soc. 1998, 129, 1938–1939.
6. Johnson, D. L.; Gladysz, J. A. Inorg. Chem. 1981, 20,
2508–2515.
7. Metal-catalyzed reductive homocoupling reaction of arylalde-
5.2.24. Reaction of 2-naphthaldehyde. Ni(cod)2 (10 mol %)
and DPPF were employed as a catalyst. Compound 5e was
obtained in 91% yield.
ˇ
hyde. For Cr see: Svatos, A.; Boland, W. Synlett 1998,
549–551; For V see: Hirao, T.; Hasegawa, T.; Muguruma, Y.;
Ikeda, S. J. Org. Chem. 1996, 61, 366–367; For Sm see:
Nomura, R.; Matsuno, T.; Endo, T. J. Am. Chem. Soc. 1996,
118, 11666–11667; For Ce see: Groth, U.; Jeske, M. Synlett
2001, 129–131.
Supplementary data
Supplementary data associated with this article can be found
in the online version, at doi:10.1016/j.tet.2006.03.124.
8. For diols see: Takenaka, N.; Xia, G.; Yamamoto, H. J. Am.
Chem. Soc. 2004, 126, 13198–13199.