PNSO ligands as a tool to study metal bonding of electron-deficient sulfinyl groups

Article abstract of DOI:10.1002/ejic.200900521

A family of N-phosphanylsulfinamide (PNSO) ligands with electron-deficient sulfinyl groups was synthesized. Reaction with Co₂-alkyne complexes yields P,S-bridged complexes. These complexes were used to study the metal bonding of different sulfinyl groups. IR spectroscopy, X-ray analysis, and Pauson-Khand reactivity studies indicated that electron-deficient sulfinyl groups provide enhanced S metal bonding. The mean CO stretching frequencies (Δv) for these complexes closely correlates with the χ_i parameter computed by Tolman for phosphane ligands. Among the studied sulfinyl groups, the trifluoromethyl PNSO ligand afforded the strongest sulfur-metal bond. Wiley-VCH Verlag GmbH & Co. KGaA.

Full text of DOI:10.1002/ejic.200900521

FULL PAPER
DOI: 10.1002/ejic.200900521
PNSO Ligands as a Tool to Study Metal Bonding of Electron-Deficient
Sulfinyl Groups
Marc Revés,[a] Antoni Riera,*[a] and Xavier Verdaguer*[a]
Keywords: S ligands / Electron-deficient compounds / Cobalt / Cycloaddition
A family of N-phosphanylsulfinamide (PNSO) ligands with
electron-deficient sulfinyl groups was synthesized. Reaction
with Co2–alkyne complexes yields P,S-bridged complexes.
These complexes were used to study the metal bonding of
different sulfinyl groups. IR spectroscopy, X-ray analysis, and
Pauson–Khand reactivity studies indicated that electron-
deficient sulfinyl groups provide enhanced S metal bonding.
The mean CO stretching frequencies (∆ν) for these com-
plexes closely correlates with the χi parameter computed by
Tolman for phosphane ligands. Among the studied sulfinyl
groups, the trifluoromethyl PNSO ligand afforded the strong-
est sulfur–metal bond.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2009)
Introduction
Sulfoxides and sulfinamides have recently emerged as a
valuable class of ligands in metal catalysis.[1] Compared to
phosphanes, sulfinyl ligands offer a series of advantages: the
chiral information is always adjacent to the bound metal,
they can be easily synthesized in optically pure form, and
they are stable to air.[2] Depending on the metal and other
structural factors, the sulfinyl ligand may bind the metal
either through the oxygen or sulfur atom.[3] Although there
is extensive knowledge about the binding capacity of dmso
and the usual PhSO, p-TolSO, MeSO, and tert-BuSO frag-
ments, there are virtually no examples of metal-bound, elec-
tron-deficient sulfoxides or sulfinamides.[4]
We recently introduced N-phosphanyl sulfinamide li-
gands (PNSO) and studied their coordination behavior
towards cobalt and rhodium complexes (Figure 1).[5–7]
Compounds 1 and 2 were shown to function invariably as
P,S-bridging ligands towards alkyne–dicobaltcarbonyl com-
plexes. In light of this observation, here we used PNSO li-
gands to study the π acidity and metal-binding capacity of
electron-deficient sulfinyl groups. Here we report on the
synthesis of PNSO ligands bearing electron-withdrawing
groups (EWGs) on sulfur, the preparation of their corre-
sponding dicobalt–alkyne complexes, and how the elec-
tronic nature of the ligand affects sulfur–metal bonding.
Figure 1. PNSO ligands and the corresponding Co2–alkyne com-
plexes.
Results and Discussion
Racemic PNSO ligands with EWGs on sulfur were pre-
pared in a two-step synthesis starting from the correspond-
ing sulfonyl chlorides (Table 1). Following the experimental
procedure described by Harmata and co-workers, treatment
of sulfonyl chloride with benzylamine, triethylamine, and
PPh3 produced a mixture of benzylsulfinyl amide and ben-
zylsulfonyl amide, in which the former was the major prod-
uct.[8] A variety of sulfonyl chlorides are commercially avail-
able, thereby making these compounds an ideal starting ma-
terial to prepare an array of sulfinamides with EWGs. Col-
umn chromatography provided pure sulfinamides I in mod-
erate to good yields, except for perfluorobenzenesulfonyl
chloride, which failed to produce the desired sulfinamide
(Table 1, Entry 7). From the corresponding isolated sulfin-
amides I, deprotonation, reaction with Ph2PCl, and protec-
[a] Unitat de Recerca en Síntesi Asimètrica (URSA-PCB), Institute
for Research in Biomedicine (IRB Barcelona), Departament de
Química Orgànica, Universitat de Barcelona,
c/Baldiri Reixac 10, 08028 Barcelona, Spain
Fax: +34-403-70-95
E-mail: xavier.verdaguer@irbbarcelona.org
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.200900521.
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Study of Metal Bonding of Electron-Deficient Sulfinyl Groups
tion with BH3–SMe2 afforded borane-protected PNSO li- achieved at lower temperature (40 °C), whereas S coordina-
gands 10–16 in 31–70% yield. As described previously, bo-
rane protection stabilizes the functionalities contained in
the PNSO ligands towards oxygen migration and hydroly-
sis.[6] Protected ligands II are stable oils or solids that can
be stored in the fridge for several months without decompo-
sition.
tion was promoted at 65 °C (Table 2, Entries 5 and 6). Thus,
in general, good to excellent yields of the desired bridged
complexes were obtained. Although sulfinyl groups con-
taining o-fluoro- and o-chlorobenzene fragments provided
efficient S coordination, the analogous ligand with an o-
nitrobenzene moiety failed to yield the bridged compound
(Table 2, Entry 3).[9] Benzene groups with an EWG (CF3,
NO2) in either the meta or para positions allowed the for-
mation of bridged complexes (Table 2, Entries 4–6). Finally,
PNSO ligand 16 containing a trifluoromethyl sulfinyl
group, provided the corresponding bridged complexes in
good yield (Table 2, Entries 7 and 8). Resulting bridged
complexes 10a–16b were obtained as a 1:1 mixture of dia-
stereomers and they could not be separated by chromatog-
raphy. This result is in concordance with p-tolylsulfinamide
ligand (2), which showed lower selectivity than its tert-butyl
analog (1).
At this point, we observed that even the exceptionally
electron-deficient CF3SO group showed the capacity to
bind to cobalt. To the best of our knowledge, there are vir-
tually no examples of sulfoxides with EWGs bonded to
transition-metal complexes.[10] We propose that, in analogy
to phosphane ligands, PNSO–cobalt carbonyl complexes
10a–16a could allow the study of the S-binding properties
of electron-deficient sulfinyl groups. The electronic proper-
ties of phosphane ligands can be conveniently analyzed by
the stretching frequencies of the CO ligands in Ni(PR3)CO3
and Cr(PR3)CO5 complexes.[11–13] σ-Donor phosphanes
will increase metal electron density, which increases back-
bonding to CO ligands, thus eventually resulting in lower
IR frequencies. In contrast, strong π-acceptor ligands will
compete for metal electron density with the CO ligands and
the CO stretching frequencies will remain high. Thus, CO
stretching frequencies allows the ranking of phosphanes
from strongly σ basic (tBu3P) to strongly π acidic (F3P).
Dicobalt–alkyne complexes with a bridging PNSO ligand
Table 1. Synthesis of borane-protected racemic PNSO ligands.
Entry
R
I, Yield [%][c]
II, Yield [%][c]
1
2
3
4
5
6
7
8
o-ClC6H4
o-FC6H4
o-NO2C6H4
p-NO2C6H4
p-CF3C6H4
3,5-CF3C6H4
C6F5
3, 63
4, 71
5, 41
6, 42
7, 52
8, 42
–
10, 50
11, 56
12, 40
13, 31
14, 61
15, 63
–
CF3
9, 45
16, 70
[a] BnNH2 (1 equiv.), triethylamine (TEA; 2 equiv.), PPh3
(1 equiv.), CH2Cl2 0 °C 1 h. [b] BuLi, thf, –78 °C, Ph2PCl; then,
BH3·SMe2 at –30 °C. [c] Yield refers to compounds purified by
flash chromatography.
With the novel PNSO ligands in hand, we proceeded to
check their binding capacity to dicobalt–alkyne complexes.
Deprotection with DABCO and a ligand exchange reaction
with trimethylsilylacetylenedicobalt hexacarbonyl complex
was conducted in a one-pot procedure by thermal acti-
vation at 65 °C in toluene (Table 2). TLC monitoring dis-
closed the formation of two novel complexes: the initial
nonbridged P-coordinated intermediate and the final
bridged P,S-coordinated complex. In most cases, heating for
2–5 h at 65 °C sufficed for full conversion to the final
bridged complex. In other cases, a better yield was observed have no symmetry, and the four carbonyl ligands originate
when the initial deprotection/P coordination sequence was an equal amount of CO stretching bands (A, B, C, D; Fig-
Table 2. Ligand exchange reactions with dicobalt–alkyne complexes.
Entry
L
R
X
Temperature [°C]
Time [h]
Yield [%][a]
Complex[b]
1
2
3
4
5
6
7
8
10
11
12
13
14
15
16
16
o-ClC6H4
o-FC6H4
o-NO2C6H4
p-NO2C6H4
p-CF3C6H4
3,5-CF3C6H4
CF3
TMS
TMS
TMS
TMS
TMS
TMS
TMS
Ph
65
65
65
4
5
4
82
75
–
65
77
57
82
61
10a
11a
–
13a
14a
15a
16a
16b
65
3
40 Ǟ 65
40 Ǟ 65
65
3/2[c]
6/2[c]
5
CF3
65
6
[a] Yield refers to complex purified by flash chromatography. [b] Complexes were isolated as a 1:1 mixture of diastereomers as determined
1
by H NMR spectroscopy. [c] First value represents time at 40 °C, second value represents time at 65 °C.
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M. Revés, A. Riera, X. Verdaguer
FULL PAPER
ure 2). The lower frequency band (D) is also the less intense Table 3. Metal carbonyl IR frequencies for PNSO–cobalt carbonyl
complexes.
and it usually overlaps partially with the C band. Con-
versely, the highest frequency band (A) corresponding to
the symmetric stretching of the four carbonyl ligands is iso-
lated from the other CO bands.[14]
Entry
R
Complex Band A Mean ν
∆ν
[cm–1]
[cm–1]
[cm–1][a]
1[b]
2[c]
3
4
5
6
7
8
tBu
1a
2032
2035
2037
2037
2039
2040
2043
2047
2002
2005
2007
2007
2010
2011
2014
2019
0
3
5
5
8
9
12
17
p-MeC6H4
o-ClC6H4
o-FC6H4
p-NO2C6H4
p-CF3C6H4
3,5-CF3C6H4
CF3
2a
10a
11a
13a
14a
15a
16a
[a] ∆ν = (mean ν) – (mean ν for 1a). [b] Data from ref.[5] [c] Data
from ref.[6]
was 2.13 Å, a distance shorter than that of p-tolyl sulfinyl
(2.17 Å) and the tert-butyl sulfinyl examples (2.19 Å).[5,6]
The preceding bond lengths further validate the IR spectro-
scopic data observed, and are indicative that, for sulfinyl
ligands, the presence of EWGs leads to increased ligand–
metal bond strength.
Figure 2. Representative metal carbonyl IR spectra for complexes
10a–16b.
Complexes of trimethylsilylalkyne (1a–16a) were ranked
on the basis of their CO stretching frequencies, as shown in
Table 3. The same ranking resulted independently of
whether band A or the mean stretching frequency (A, B,
and C) was used. Taking the complex with a tert-butyl sulf-
inyl group as a reference, we calculated the ∆ν parameter
as the difference of the mean frequencies of the two com-
plexes. The ∆ν parameter is indicative of the π acidity of
the ligand: High ∆ν indicated increased π acidity. In agree-
ment with this observation, the p-tolyl sulfinyl group pro-
vided lower ∆ν than the corresponding phenyl sulfinyl
groups with the EWG on the aryl ring. Phenyl groups with
o-chloro and o-fluoro substitution provided similar ∆ν val-
ues (Table 3, Entries 3 and 4). p-Nitrophenyl provided lower
∆ν (8 cm–1) than p-trifluoromethylphenyl (9 cm–1) and 3,5-
bis(trifluoromethyl)phenyl (12 cm–1). Finally, the CF3
group alone provided the highest ∆ν value (17 cm–1). The
values of ∆ν calculated for complexes 1a–16a correlate well
with the electronic parameter χi calculated by Tolman for
the contribution of a single substituent R in a phosphane
(PR3).[11] In phosphanes, for example, the p-tolyl and the
CF3 groups showed χi values of 3.5 and 19.6, respectively.
Further confirmation of the binding properties of the
CF3–SO came through single-crystal X-ray studies. The
Figure 3. ORTEP plot for the crystal structure of complex 16a.
Thermal ellipsoids shown at 50% probability. Only one enantiomer
of the racemate is shown. Bond length S–Co = 2.13 Å.
Finally, in a reactivity study we compared Co2–PNSO
original 1:1 diastereomeric mixture of complex 16a was complexes containing a CF3SO group with the correspond-
crystallized out from hexanes to obtain a single dia- ing pTolSO and the tBuSO analogs in the stoichiometric
stereomer as a racemate.[15] One of the two enantiomers intermolecular Pauson–Khand reaction (Table 4). Thus, for
contained in the unit cell is shown in Figure 3. The X-ray both TMS- and Ph–alkyne complexes, the shortest reaction
structure confirmed that the PNSO ligand in complex 16a times observed were for complexes 1a and 1b with a tert-
adopts a bridging disposition. The P,S ligand is positioned butyl sulfinyl group (Table 4, Entries 1 and 4). Of the p-
anti with respect the alkyne substituent (TMS) to minimize tolyl and CF3 ligands, the latter were noticeably less reactive
steric interactions. Interestingly, the S–Co distance for 16a for the corresponding TMS complex (Table 4, Entries 2 and
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Eur. J. Inorg. Chem. 2009, 4446–4453

Study of Metal Bonding of Electron-Deficient Sulfinyl Groups
3), whereas both groups of ligands showed similar reaction ity studies of complexes 16a and 16b, both bearing a CF3SO
times for phenylacetylene-derived complexes (Table 4, En- group, confirmed that electron-deficient sulfinyl groups
tries 5–8). In general, a higher strength of the S–Co bond provide enhanced metal bonding. Given these interesting
resulted in longer reaction times. These observations can be properties, electron-deficient sulfinyl groups should find
rationalized on the basis of the hemilabile character of the further applications in metal catalysis and synthesis.
PNSO ligands. Hemilabile ligands provide empty coordina-
tion sites for the incoming olefin and, as a result, accelerate
the cycloaddition process. Accordingly, tert-butyl PNSO li-
Experimental Section
gands showed the highest hemilabile character of the series,
Experimental Details: All reactions were carried out under a nitro-
whereas the CF3SO ligand showed the lowest and behaved
gen atmosphere in dried solvents; thf was dried with sodium/benzo-
more like a solid bridged ligand.
phenone, toluene over sodium, and dichloromethane over CaH2.
Thin-layer chromatography was carried out by using TLC alumi-
num sheets with silica gel (Merck 60 F254). Chromatography purifi-
Table 4. Stoichiometric Pauson–Khand reaction of several PNSO–
cobalt complexes.
cations were carried out by using flash-grade silica gel (SDS Chro-
matogel 60 ACC, 35–70 µm). NMR spectra were recorded at 23 °C
with a Varian Mercury 400 and a Varian Unity 300 spectrometer.
1H NMR and 13C NMR spectra were referenced either to relative
internal TMS or to residual solvent peaks. 31P NMR spectra were
referenced to phosphoric acid. Signal multiplicities in the 13C
NMR spectra were assigned by DEPT and HSQC experiments.
Melting points were determined with a Büchi melting point appara-
tus and are not corrected. IR spectra were recorded with an FTIR
apparatus. HRMS were recorded by using an electrospray ioniza-
tion apparatus. Sulfinamides 3–5, 7, and 9 have been described pre-
viously in the literature.[8]
Entry
R
X
Complex
T
[°C]
Yield[a] Time[b]
[%]
[h]
1[c]
2
tBu
pTol
CF3
tBu
pTol
CF3
pTol
CF3
TMS
TMS
TMS
Ph
Ph
Ph
1a
2a
16a
1b
2b
16b
2b
16b
70
70
70
r.t.
r.t.
r.t.
70
70
99
72
94
99
76
88
95
89
20
48
65
4
28
28
1
3
4[c]
5
General Procedure for the Preparation of Sulfinamides: To a solu-
tion of sulfonyl chloride (1.59 mmol) in CH2Cl2 (5 mL) at 0 °C was
added a solution of triphenylphosphane (417 mg, 1.59 mmol), ben-
zylamine (0.17 mL, 1.59 mmol), and triethylamine (0.44 mL,
3.19 mL) in CH2Cl2 (5 mL) by using a syringe pump over a period
of 1 h. After the addition, TLC showed that the sulfonyl chloride
was consumed. The reaction mixture was concentrated under vac-
uum. The crude mixture was purified by column chromatography
(hexanes/EtOAc, 90:10) to give the desired sulfinamide.
6
7
8
Ph
Ph
1
[a] Yield refers to product purified by flash chromatography.
[b] Time for full conversion of starting complex (TLC). [c] Data
from ref.[5]
The bond length (or bond strength) is a physical property
that depends ultimately on different parameters, one of
them being the π acidity of the ligand. Other important
parameters are the steric bulk of the ligand (Tolman’s cone
angle) and the σ-donor capacity. For phosphane ligands,
quantitative analysis of ligand effects (QALE) has demon-
strated that increasing π acidity and reducing the cone angle
results in shortening the M–L bond length.[16] QALE analy-
sis has also shown that π acidity has a stronger influence in
bond length than steric and σ-donor parameters. In that
respect, the CF3SO ligand shows both increased π acidity
and reduced steric bulk, which leads to a stronger sulfur–
metal bond.
N-Benzyl-p-nitrophenylsulfinamide (6): According to the general
procedure, p-nitrophenylsulfonyl chloride (1.0 g, 4.51 mmol) in
CH2Cl2 (13 mL), triphenylphosphane (1.18 g, 4.51 mmol), benzyla-
mine (0.49 mL, 4.51 mmol), and triethylamine (1.25 mL,
9.02 mmol) in CH2Cl2 (13 mL). Flash chromatography (hexanes/
EtOAc, 90:10) afforded 6 (511 mg, 42%) as a yellow solid. M.p.
1
135–136 °C. IR (KBr): ν = 3208, 2917, 2860, 1525, 1343 cm–1. H
˜
2
3
NMR (400 MHz, CDCl3): δ = 3.87 (dd, JH,H = 14 Hz, JH,H
=
2
3
7 Hz, 1 H, CH2Ph), 4.27 (dd, JH,H = 14 Hz, JH,H = 5 Hz, 1 H,
CH2Ph), 4.47 (s.a, 1 H, NH), 7.23–7.34 (m, 5 H), 7.96 (d, J = 9 Hz,
2 H), 8.36 (d, J = 9 Hz, 2 H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 44.9 (CH2), 124.2 (CH), 127.7 (CH), 128.2 (CH), 128.5 (CH),
129.0 (CH), 137.1 (C), 149.8 (C), 151.1 (C) ppm. MS [ESI, H2O/
CH3CN (1:1), 1% HCO2H]: m/z (%) = 108 (100) [C7H9N + H]+,
277 (11) [M + H]+. HRMS (ESI): calcd. for C13H13N2O3S [M +
H] 277.0644; found 277.0641. C13H12N2O3S (276.31): calcd. C
56.51, H 4.38, N 10.14, S 11.60; found C 56.28, H 4.31, N 10.03,
S 11.41.
Conclusions
In summary, here we synthesized a family of N-phos-
phanylsulfinamide (PNSO) ligands with electron-deficient
sulfinyl groups from the corresponding sulfonyl chlorides in
two steps. These ligands behaved like P,S-bidentate ligands
in response to Co2–alkyne complexes, thereby providing
bridged tetracarbonyl complexes. The binding capacity of
the different sulfinyl groups was examined on the basis of
stretching frequencies of the CO ligands. This approach al-
lowed the ranking of these groups on the basis of their π
N-Benzyl-3,5-bis(trifluoromethyl)phenylsulfinamide (8): According
to the general procedure, 3,5-bis(trifluoromethyl)phenylsulfonyl
chloride (500 mg, 1.59 mmol) in CH2Cl2 (5 mL), triphenylphos-
phane (417 mg, 1.59 mmol), benzylamine (0.17 mL, 1.59 mmol),
and triethylamine (0.44 mL, 3.19 mmol) in CH2Cl2 (15 mL). Flash
chromatography (hexanes/EtOAc, 95:5) afforded 8 (244 mg, 42%)
1
as a colorless oil. IR (KBr): ν = 3213, 1357, 1279, 1139 cm–1. H
˜
2
3
NMR (400 MHz, CDCl3): δ = 3.90 (dd, JH,H = 13 Hz, JH,H
acidity. Finally, X-ray analysis and Pauson–Khand reactiv- 6 Hz, 1 H, CH2Ph), 4.24 (dd, JH,H = 13 Hz, JH,H = 5 Hz, 1 H,
=
2
3
Eur. J. Inorg. Chem. 2009, 4446–4453
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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4449

M. Revés, A. Riera, X. Verdaguer
CH2Ph), 4.58 (t, J = 5 Hz, 1 H, NH), 7.21 (m, 2 H), 7.26–7.30 (m, 128.3 (d, JC,P = 41 Hz, 1 C), 128.9 (d, JC,P = 11 Hz, CH), 129.0 (d,
FULL PAPER
3 H), 7.97 (s, 1 H), 8.21 (s, 2 H) ppm. 13C NMR (100 MHz,
CDCl3): δ = 44.5 (CH2), 122.8 (q, JC,F = 272 Hz, 1 C), 124.9 (m,
CH), 126.9 (d, JC,F = 3 Hz, CH), 128.1 (CH), 128.3 (CH), 128.6
(CH), 132.6 (q, JC,F = 33 Hz, 1 C), 136.8 (C), 147.5 (C) ppm. 19F
JC,P = 10 Hz, CH), 131.1 (d, J = 12 Hz, 1 C), 132.3 (d, JC,P = 2 Hz,
CH), 132.4 (d, JC,P = 2 Hz, CH), 133.5 (CH), 133.6 (CH), 134.1
(d, JC,F = 8 Hz, CH), 136.3 (C), 158.8 (d, JC,F = 250 Hz, 1 C) ppm.
31P NMR (121 MHz, CDCl3): δ = 81.4 ppm. 19F NMR (376 MHz,
NMR (376 MHz, CDCl3): δ = –63.3 ppm. MS [ESI, H2O/CH3CN CDCl3): δ = –110.67 ppm. MS [ESI, H2O/CH3CN (1:1), 1%
(1:1), 1% HCO2H): m/z (%) = 368 (40) [M + H]+, 390 (21) [M + HCO2H]: m/z (%) = 446 (100) [M – H]+, 917 (21) [2M + Na]+.
Na]+. HRMS (ESI): calcd. for C15H12F6NOS [M + H] 368.0538;
found 368.0540.
HRMS (ESI): calcd. for C25H23BFNOPS [M – H] 446.1309; found
446.1310.
General Procedure for the Synthesis of the Borane Complexes of
(S)-N-Phosphanyl-p-Tolylsulfinamides: An oven-dried, one-necked,
round-bottomed flask (100 mL) equipped with magnetic stirring
bar was charged with the corresponding sulfinamide (1.89 mmol)
under an atmosphere of nitrogen. Anhydrous thf (20 mL) was
added, and the solution was cooled to –78 °C. To this solution
was added dropwise by syringe BuLi (2.5  in hexanes, 0.83 mL,
N-Benzyl-N-diphenylphosphanyl-o-nitrophenylsulfinamide
Borane
Complex (12): According to the general procedure, 5 (300 mg,
1.08 mmol), BuLi (0.48 mL, 1.19 mmol), Ph2PCl (0.24 mL,
1.29 mmol), and BH3–SMe2 (0.13 mL, 1.40 mmol). Flash
chromatography (hexane/EtOAc, 90:10) afforded 12 (240 mg, 40%)
as a yellow foam. IR (KBr): ν =3064, 2922, 2387, 1529, 1437,
˜
1
1344 cm–1. H NMR (400 MHz, CDCl3): δ = 1.03–1.86 (br., 3 H,
2
3
2.08 mmol). After stirring for 15 min, Ph2PCl (2.08 mmol) was BH3), 4.23 (dd, JH,H = 17 Hz, JH,P = 11 Hz, 1 H, CH2Ph), 4.53
2
3
added by syringe; the mixture turned yellow. The solution was
stirred for 1 h, during this time the temperature was raised to
–30 °C. Immediately, BH3–SMe2 (0.27 mL, 2.83 mmol) was added
and the mixture was stirred for 20 min. The mixture was warmed
(dd, JH,H = 17 Hz, JH,P = 6 Hz, 1 H, CH2Ph), 6.45 (d, J = 8 Hz,
1 H), 6.77 (m, 1 H), 6.83 (m, 1 H), 7.26–7.30 (m, 1 H), 7.36–7.50
(m, 3 H), 7.56 (m, 6 H), 7.69–7.77 (m, 3 H), 7.97 (m, 1 H), 8.11 (m,
1 H), 8.33 (d, J = 7 Hz, 1 H) ppm. 13C NMR (100 MHz, CDCl3): δ
to 0 °C; H2O (10 mL) and Et2O (10 mL) were added carefully (H2 = 46.6 (CH2), 125.0 (CH), 126.5 (2 CH), 126.6 (CH), 127.0 (d, JC,P
evolves). The aqueous layer was washed with Et2O (10 mL), and
the combined organic layer was dried with anhydrous magnesium
sulfate, filtered, and concentrated in vacuo. The resulting crude
mixture was purified on silica gel (hexane/EtOAc, 90:10) to obtain
the desired N-phosphanylsulfinamides protected with borane.
= 62 Hz, 1 C), 127.9 (CH), 128.3 (CH), 128.5 (d, JC,P = 54 Hz, 1
C), 129.0 (d, JC,P = 11 Hz, CH), 129.3 (d, JC,P = 11 Hz, CH), 131.1
(d, JC,P = 11 Hz, 1 C), 132.5 (CH), 132.6 (d, JC,P = 2 Hz, CH),
133.9 (d, JC,P = 11 Hz, CH), 134.0 (d, JC,P = 11 Hz, CH) 134.3
(CH), 136.6 (d, JC,P = 3 Hz, 1 C), 145.9 (C) ppm. 31P NMR
(121 MHz, CDCl3): δ = 85.2 ppm. MS [ESI, H2O/CH3CN (1:1),
1% HCO2H]: m/z (%) = 308 (100) [C12H12BN2O3PS + H]+, 473
(48) [M – H]+. HRMS (ESI): calcd. for C25H23BN2O3PS [M – H]
473.1254; found 473.1258.
N-Benzyl-N-diphenylphosphanyl-o-chlorophenylsulfinamide Borane
Complex (10): According to the general procedure, 3 (166 mg,
0.62 mmol), BuLi (0.28 mL, 0.69 mmol), Ph2PCl (0.13 mL,
0.69 mmol), and BH3–SMe2 (0.08 mL, 0.81 mmol). Flash
chromatography (hexane/EtOAc, 95:5) afforded 10 (144 mg, 50%) N-Benzyl-N-diphenylphosphanyl-p-nitrophenylsulfinamide
Borane
as a white foam. IR (KBr): ν = 3058, 2388, 1450, 1437, 1105 cm–1. Complex (13): According to the general procedure, 6 (235 mg,
˜
1H NMR (400 MHz, CDCl3): δ = 0.85–1.79 (br., 3 H, BH3), 4.28
0.85 mmol), BuLi (0.37 mL, 0.97 mmol), Ph2PCl (0.18 mL,
1.02 mmol), and BH3–SMe2 (0.10 mL, 1.10 mmol). Flash
chromatography (hexane/EtOAc, 90:10) afforded 13 (124 mg, 31%)
2
3
2
(dd, JH,H = 17 Hz, JH,P = 12 Hz, 1 H, CH2Ph), 4.77 (dd, JH,H
3
= 17 Hz, JH,P = 7 Hz, 1 H, CH2Ph), 6.68 (m, 2 H), 6.80 (m, 2 H),
6.91 (dd, J = 8 Hz, J = 1 Hz, 1 H), 7.05 (t, J = 8 Hz, 1 H), 7.17 (t,
J = 7 Hz, 1 H), 7.43–7.60 (m, 6 H), 7.75 (m, 1 H), 7.88 (m, 3 H),
as a yellow foam. IR (KBr): ν = 2923, 2853, 2389, 1526, 1109 cm–1.
˜
1H NMR (400 MHz, CDCl3): δ = 0.85–1.83 (br., 3 H, BH3), 4.47
7.97 (m, 2 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 45.7 (CH2), (dd, JH,H = 16 Hz, JH,P = 13 Hz, 1 H, CH2Ph), 4.75 (dd, JH,H
2
3
2
3
126.5 (CH), 127.07 (CH), 127.11 (CH), 127.4 (CH), 127.7 (CH),
= 16 Hz, JH,P = 6 Hz, 1 H, CH2Ph), 6.85–6.92 (m, 5 H), 7.40 (d,
J = 9 Hz, 2 H), 7.49–7.63 (m, 6 H), 7.83–7.91 (m, 4 H), 7.93 (d, J
127.8 (d, JC,P = 64 Hz, 1 C), 128.5 (d, JC,P = 59 Hz, 1 C), 128.8 (d,
JC,P = 11 Hz, CH), 129.0 (d, JC,P = 10 Hz, CH), 129.9 (CH), 131.1 = 9 Hz, 2 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 46.2 (d, JC,P
(d, JC,P = 12 Hz, 1 C), 132.3 (CH), 132.4 (CH), 133.0 (CH), 133.6
= 4 Hz, CH2), 123.5 (CH), 126.7 (d, JC,P = 56 Hz, 1 C), 126.9 (CH),
(d, JC,P = 11 Hz, CH), 133.7 (d, JC,P = 11 Hz, CH), 136.0 (C), 127.2 (CH), 127.8 (CH), 128.0 (d, JC,P = 58 Hz, 1 C), 128.8 (CH),
139.5 (d, JC,P = 9 Hz, 1 C) ppm. 31P NMR (121 MHz, CDCl3): δ 129.1 (d, JC,P = 11 Hz, CH), 129.3 (d, JC,P = 10 Hz, CH), 132.4 (d,
= 82.5 ppm. MS [ESI, H2O/CH3CN (1:1), 1% HCO2H]: m/z (%) =
JC,P = 3 Hz, CH), 132.7 (d, JC,P = 2 Hz, CH), 133.0 (d, JC,P =
462 (100) [M – H]+, 949 (31) [2M + Na]+. HRMS (ESI): calcd. for 11 Hz, CH), 133.1 (d, JC,P = 11 Hz, CH), 135.8 (C), 149.2 (C),
C25H23BClNOPS [M – H] 462.1013; found 462.1014.
149.5 (d, JC,P = 6 Hz, 1 C) ppm. 31P NMR (121 MHz, CDCl3): δ
= 80.4 ppm. MS [ESI, H2O/CH3CN (1:1), 1% HCO2H]: m/z (%) =
N-Benzyl-N-diphenylphosphanyl-o-fluorophenylsulfinamide Borane
Complex (11): According to the general procedure, 4 (424 mg,
1.70 mmol), BuLi (0.75 mL, 1.87 mmol), Ph2PCl (0.38 mL,
2.04 mmol), BH3–SMe2 (0.19 mL, 2.04 mmol). Flash chromatog-
raphy (hexane/EtOAc, 95:5) afforded 11 (400 mg, 56%) as a white
308 (42), 473 (28) [M
–
H]+. HRMS (ESI): calcd. for
C25H23BN2O3PS [M – H] 473.1254; found 473.1263.
N-Benzyl-N-diphenylphosphanyl-p-trifluoromethylphenylsulfinamide
Borane Complex (14): According to the general procedure, 7
(400 mg, 1.34 mmol), BuLi (0.59 mL, 1.47 mmol), Ph2PCl
(0.30 mL, 1.61 mmol), and BH3–SMe2 (0.16 mL, 1.74 mmol).
Flash chromatography (hexane/EtOAc, 90:10) afforded 14 (402 mg,
foam. IR (KBr): ν =3060, 2388, 1470, 1437 cm–1. 1H NMR
˜
2
(400 MHz, CDCl3): δ = 0.82–1.86 (br., 3 H, BH3), 4.40 (dd, JH,H
3
2
= 17 Hz, JH,P = 13 Hz, 1 H, CH2Ph), 4.74 (dd, JH,H = 17 Hz,
3JH,P = 8 Hz, 1 H, CH2Ph), 6.66 (t, J = 9 Hz, 1 H), 6.87 (s.a, 4 H), 61%) as a white foam. IR (KBr): ν = 3061, 2389, 1437, 1324 cm–1.
˜
7.07 (t, J = 8 Hz, 1 H), 7.17–7.19 (m, 1 H), 7.46–7.57 (m, 6 H), 1H NMR (400 MHz, CDCl3): δ = 0.79–1.91 (br., 3 H, BH3), 4.44
2
3
2
7.69–7.77 (m, 2 H), 7.82–7.87 (m, 2 H), 7.92–7.97 (m, 2 H) ppm. (dd, JH,H = 16 Hz, JH,P = 14 Hz, 1 H, CH2Ph), 4.73 (dd, JH,H
13C NMR (100 MHz, CDCl3): δ = 46.1 (d, JC,P = 4 Hz, CH2), 115.8 = 16 Hz, 3JH,P = 7 Hz, 1 H, CH2Ph), 6.86–6.93 (m, 5 H), 7.36–7.41
(d, JC,F = 20 Hz, CH), 124.6 (d, JC,F = 4 Hz, CH), 126.8 (CH), (m, 4 H), 7.47–7.61 (m, 6 H), 7.82–7.90 (m, 4 H) ppm. 13C NMR
127.6 (CH), 127.7 (CH), 127.9 (CH), 128.0 (d, JC,P = 47 Hz, 1 C),
(100 MHz, CDCl3): δ = 46.2 (d, JC,P = 4 Hz, CH2), 123.3 (q, JC,F
4450
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© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2009, 4446–4453

Study of Metal Bonding of Electron-Deficient Sulfinyl Groups
= 271 Hz, 1 C), 125.5 (q, JC,F = 4 Hz, CH), 126.3 (CH), 127.1
(CH), 127.7 (CH), 128.2 (d, JC,P = 58 Hz, 1 C), 128.7 (CH), 129.0
Co2(µ-TMSC2H)(CO)4(µ-C25H21ClNOPS) (10a): According to the
general procedure, 10 (70 mg, 0.15 mmol), DABCO (26 mg,
(d, JC,P = 11 Hz, CH), 129.2 (d, JC,P = 10 Hz, CH), 129.3 (d, JC,P 0.23 mmol), and trimethylsilylacetylene dicobalt complex (63 mg,
= 62 Hz, 1 C), 132.2 (d, JC,P = 2 Hz, CH), 132.5 (d, JC,P = 2 Hz, 0.165 mmol). The mixture was kept at 65 °C for 4 h. Flash
CH), 133.0 (d, JC,P = 11 Hz, CH), 133.20 (d, JC,P = 11 Hz, CH), chromatography (hexanes/EtOAc, 95:5) afforded a mixture of dia-
133.21 (q, JC,F = 32 Hz, 1 C) 136.0 (d, J = 3 Hz, 1 C), 146.6 (d, J stereomers 10a (1:1, 95 mg, 82%) as a red solid. IR (film): ν =
˜
1
= 6 Hz, 1 C) ppm. 31P NMR (121 MHz, CDCl3): δ = 79.5 ppm.
2961, 2956, 2037, 2003, 1981 cm–1. H NMR (400 MHz, C6D6): δ
19F NMR (376 MHz, CDCl3): δ = –63.40 ppm. MS [ESI, H2O/ = 0.32/0.41 (2 s, 9 H, SiMe3), 4.10 (dd, JH,H = 17 Hz, JH,P
=
2
3
CH3CN (1:1), 1% HCO2H]: m/z (%) = 496 (100) [M – H]+, 520
(8) [M + Na]+, 1017 (20) [2M + Na]+. HRMS (ESI): calcd. for
C26H23BF3NOPS [M – H] 496.1277; found 496.1278.
5 Hz, 2 H, CH2Ph), 4.65/4.88 (2 d, J = 16/17 Hz, 1 H, CH2Ph),
5.69/6.00 (2 d, 3JH,P = 7 Hz/3JH,P = 12 Hz, 1 H, HCϵCTMS), 5.81
(d, J = 7 Hz, 1 H), 6.35–6.58 (m, 13 H), 6.75(m, 3 H), 7.04–7.21
(m, with solvent peak, 9 H), 7.79–7.90 (m, 7 H), 8.08–8.28 (m, 5
H) ppm. 31P NMR (121 MHz, C6D6): δ = 118.5/122.5 ppm. MS
[ESI, H2O/CH3CN (1:1), 1% HCO2H]: m/z (%) = 722 (21) [M +
H – 2CO]+, 750 (16) [M + H – CO]+, 778 (13) [M + H]+. HRMS
(ESI): calcd. for C34H32ClCo2NO5PSSi [M + H] 777.9855; found
777.9826.
N-Benzyl-N-diphenylphosphanyl-3,5-bis(trifluoromethyl) Phenylsulf-
inamide Borane Complex (15): According to the general procedure,
8
(240 mg, 0.65 mmol), BuLi (0.29 mL, 0.72 mmol), Ph2PCl
(0.16 mL, 0.85 mmol), and BH3–SMe2 (0.08 mL, 0.85 mmol).
Flash chromatography (hexanes/EtOAc, 80:20) afforded 15
(230 mg, 63%) as a white solid. M.p. 120–122 °C. IR (KBr): ν =
˜
2361, 2338, 1437, 1279 cm–1. 1H NMR (400 MHz, CDCl3): δ =
Co2(µ-TMSC2H)(CO)4(µ-C25H21FNOPS) (11a): According to the
general procedure, 11 (75 mg, 0.17 mmol), DABCO (28 mg,
0.25 mmol), and trimethylsilylacetylene dicobalt complex (70 mg,
0.18 mmol). The mixture was kept at 65 °C for 5 h. Flash
chromatography (hexanes/EtOAc, 95:5) afforded a mixture of dia-
2
3
0.79–1.87 (br., 3 H, BH3), 4.62 (dd, JH,H = 16 Hz, JH,P = 11 Hz,
1 H, CH2Ph), 4.84 (dd, 2JH,H = 16 Hz, 3JH,P = 6 Hz, 1 H, CH2Ph),
6.84 (m, 4 H), 7.49–7.65 (m, 10 H), 7.86–7.95 (m, 4 H) ppm. 13C
NMR (100 MHz, CDCl3): δ = 45.6 (d, JC,P = 4 Hz, CH2), 122.6
(q, JC,F = 271 Hz, 1 C), 124.8 (m, CH), 126.1 (CH), 127.5 (CH),
128.1 (CH), 128.7 (CH), 129.4 (d, JC,P = 10 Hz, CH), 129.6 (d, JC,P
= 10 Hz, CH), 132.0 (d, JC,P = 63 Hz, 1 C), 132.3 (d, JC,P = 52 Hz,
1 C), 132.6 (d, J = 2 Hz, CH), 132.9 (d, JC,P = 11 Hz, CH), 133.1
stereomers 11a (1:1, 91 mg, 75%) as a red solid. IR (film): ν =
˜
2960, 2953, 2037, 2004, 1981 cm–1. H NMR (400 MHz, C6D6): δ
1
2
= 0.33/0.39 (2 s, 9 H, SiMe3), 4.12 (m, 2 H), 4.77/4.89 (2 dd, JH,H
= 17 Hz, JH,P = 2 Hz/2JH,H = 16 Hz, JH,P = 2 Hz, 1 H, CH2Ph),
5.92 (m, 5 H), 6.05/6.19 (2 m, 1 H), 6.41–6.56 (m, 10 H), 6.70 (dd,
J = 11, 2 Hz, 1 H), 7.02–7.22 (m, with solvent peak, 12 H), 7.74–
7.94 (m, 8 H), 8.10 (m, 2 H) ppm. 31P NMR (121 MHz, C6D6): δ
= 121.2/116.6 ppm. 19F NMR (376 MHz, C6D6): δ = –104.64/
–104.99 ppm. MS [ESI, H2O/CH3CN (1:1), 1% HCO2H]: m/z (%)
= 650 (11) [M + H – 4CO]+, 678 (7) [M + H – 3CO]+, 706 (11) [M
+ H – 2CO]+, 734 (11) [M + H – CO]+, 762 (68) [M + H]+. HRMS
(ESI): calcd. for C34H32Co2FNO5PSSi [M + H] 762.0150; found
762.0148.
3
3
(d, J = 2 Hz, CH), 133.3 (d, JC,P = 11 Hz, CH), 135.7 (d, JC,P
=
3 Hz, 1 C), 146.1 (d, JC,P = 6 Hz, 1 C) ppm. 31P NMR (121 MHz,
CDCl3): δ = 80.5 ppm. 19F NMR (376 MHz, CDCl3): δ =
–63.49 ppm. MS [ESI, H2O/CH3CN (1:1), 1% HCO2H]: m/z (%) =
203 (100), 496 (25) [M – H]+, 583 (20) [M + NH4]+. HRMS (ESI):
calcd. for C27H22BF6NOPS [M – H] 564.1151; found 564.1158.
N-Benzyl-N-diphenylphosphanyltrifluoromethylsulfinamide Borane
Complex (16): According to the general procedure, 9 (530 mg,
2.37 mmol), BuLi (1.04 mL, 2.61 mmol), Ph2PCl (0.57 mL,
3.08 mmol), and BH3–SMe2 (0.29 mL, 3.08 mmol). Flash
chromatography (hexanes/EtOAc, 80:20) afforded 16 (689 mg,
Co2(µ-TMSC2H)(CO)4(µ-C25H21N2O3PS) (13a): According to the
general procedure, 13 (115 mg, 0.24 mmol), DABCO (40 mg,
0.36 mmol), and trimethylsilylacetylene dicobalt complex (100 mg,
0.26 mmol). The mixture was kept at 65 °C for 3 h. Flash
chromatography (hexane/EtOAc, 95:5) afforded a mixture of dia-
70%) as a white solid. M.p. 106–107 °C. IR (KBr): ν = 3059, 2915,
˜
1
2394, 1437 cm–1. H NMR (400 MHz, CDCl3): δ = 0.76–1.81 (br.,
3 H, BH3), 4.85 (m, 2 H, CH2Ph), 7.10 (m, 3 H), 7.25 (m, 2 H),
7.39–7.45 (m, 4 H), 7.50–7.64 (m, 6 H) ppm. 13C NMR (100 MHz,
CDCl3): δ = 47.3 (CH2), 124.0 (qd, JC,F = 341 Hz, JC,P = 8 Hz, 1
C), 127.0 (d, JC,P = 58 Hz, 1 C), 127.5 (d, JC,P = 60 Hz, 1 C), 127.8
stereomers 13a (1.5:1, 122 mg, 65%) as a red solid. IR (film): ν =
˜
2039, 2008, 1983 cm–1. H NMR (400 MHz, C6D6): δ = 0.33/0.38
1
2
3
(2 s, 9 H, SiMe3), 3.92/3.97 (2 dd, JH,H = 16 Hz, JH,P = 6 Hz/
(CH), 128.0 (CH), 128.9 (d, JC,P = 3 Hz, CH), 129.0 (d, JC,P
=
2JH,H = 16 Hz, JH,P = 6 Hz, 1 H, CH2Ph), 4.67 (d, JH,H = 18 Hz,
3
2
3 Hz, CH), 129.6 (CH), 132.4 (d, JC,P = 11 Hz, CH), 132.5 (CH),
132.7 (d, JC,P = 2 Hz, CH), 133.0 (d, JC,P = 11 Hz, CH) 134.4
(C) ppm. 31P NMR (121 MHz, CDCl3): δ = 77.9 ppm. 19F NMR
(376 MHz, CDCl3): δ = –71.35 ppm. MS [ESI, H2O/CH3CN (1:1),
1% HCO2H]: m/z (%) = 305 (29) [C19H20BNP + H]+, 408 (18)
[C20H17F3NOPS + H]+, 420 (21) [M – H]+. HRMS (ESI): calcd.
for C20H19BF3NOPS [M – H] 420.0964; found 420.0973.
2 H, CH2Ph), 5.62 (m, 4 H), 5.79/5.97 (2 d, JH,P = 7 Hz/3JH,P
=
3
12 Hz, 1 H, HCϵCTMS), 6.28 (m, 4 H), 6.48 (m, 2 H), 7.03 (m, 2
H), 7.08–7.16 (m, with solvent peak, 10 H), 7.30–7.43 (m, 8 H),
7.63 (m, 4 H), 7.77 (m, 3 H), 7.96 (m, 1 H) ppm. 31P NMR
(121 MHz, C6D6): δ = 120.9/118.6 ppm. MS [ESI, H2O/CH3CN
(1:1), 1% HCO2H]: m/z (%) = 733 (8) [M + H – 2CO]+, 761 (8) [M
+ H – CO]+, 789 (25) [M + H]+. HRMS (ESI): calcd. for
C34H32Co2N2O7PSSi [M + H] 789.0095; found 789.0100.
General Procedure for the Synthesis of PNSO Dicobaltetracarbonyl
Complexes: A Schlenk flask equipped with a magnetic stirring bar
was charged with the corresponding PNSO ligand protected with
borane (0.15 mmol), DABCO (0.23 mmol), and trimethyl-
silylacetylene dicobalt complex (0.16 mmol). The Schlenk flask was
purged with N2 and toluene (2 mL) was added. The reaction was
heated at 65 °C and was monitored by TLC. The reaction was
stopped upon disappearance of the intermediate pentacarbonyl
complex (which can be observed by TLC). The reaction mixture
was concentrated in vacuo and purified on silica gel (hexanes/
EtOAc, 95:5) to obtain the PNSO dicobaltetracarbonyl complexes
as a red solids.
Co2(µ-TMSC2H)(CO)4(µ-C26H21F3NOPS) (14a): According to the
general procedure, 14 (150 mg, 0.30 mmol), DABCO (50 mg,
0.45 mmol), and trimethylsilylacetylene dicobalt complex (126 mg,
0.33 mmol). The mixture was kept at 40 °C for 3 h and then heated
at 65 °C for 2 h. Flash chromatography (hexanes/EtOAc, 95:5) af-
forded a mixture of diastereomers 14a (1:1, 187 mg, 77%) as a red
solid. IR (film): ν = 2954, 2039, 2008, 1984 cm–1. 1H NMR
˜
(400 MHz, C6D6): δ = 0.33/0.37 (2 s, 9 H, SiMe3), 3.98/4.03 (2 dd,
2JH,H = 17 Hz, JH,P = 6 Hz/2JH,H = 17 Hz, JH,P = 6 Hz, 1 H,
3
3
2
CH2Ph), 4.72 (d, JH,H = 16 Hz, 2 H, CH2Ph), 5.67/5.71 (2 d, J
Eur. J. Inorg. Chem. 2009, 4446–4453
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4451

M. Revés, A. Riera, X. Verdaguer
FULL PAPER
= 7/8 Hz, 2 H), 5.88/5.99 (2 d, JH,P = 9 Hz/3JH,P = 11 Hz, 1 H,
3
Co2(µ–PhC2H)(CO)4(µ-C20H17F3NOPS) 16b: According to the ge-
neral procedure, 16 (85 mg, 0.20 mmol), DABCO (34 mg,
HCϵCTMS), 6.39 (m, 4 H), 6.54 (m, 2 H), 6.81/6.89 (2 d, J = 8/
8 Hz, 2 H), 7.05–7.16 (m, with solvent peak, 12 H), 7.50 (m, 4 H), 0.30 mmol), and phenylacetylene dicobalt complex (97 mg,
7.65 (m, 4 H), 7.79 (m, 2 H), 7.98 (m, 2 H) ppm. 31P NMR 0.25 mmol). The mixture was kept at 65 °C for 6 h. Flash
(121 MHz, C6D6): δ = 118.1/120.4 ppm. 19F NMR (376 MHz,
chromatography (hexanes/EtOAc, 95:5) afforded a mixture of dia-
C6D6): δ = –63.38/–63.40 ppm. MS [ESI, H2O/CH3CN (1:1), 1% stereomers 16b (1:1, 86 mg, 61%) as a red solid. IR (film): ν =
˜
HCO2H]: m/z (%) = 784 (5) [M + H – CO]+, 812 (11) [M + H]+.
2962, 2050, 2020, 1997 cm–1. 1H NMR (400 MHz, C6D6): δ = 4.47/
HRMS (ESI): calcd. for C35H32Co2F3NO5PSSi [M + H] 812.0118; 4.67 (2 dd, JH,H = 17 Hz, JH,P = 7 Hz/2JH,H = 17 Hz, JH,P
=
=
2
3
3
3
found 812.0104.
7 Hz, 1 H, CH2Ph), 4.79 (m, 2 H, CH2Ph), 5.85/6.02 (2 d, JH,P
10 Hz/3JH,P = 8 Hz, 1 H, HCϵCPh), 6.57/6.03 (2 d, J = 6/6 Hz, 2
H), 6.82 (m, 11 H), 6.91–7.31 (m, with solvent peak, 16 H), 7.63–
7.73 (m, 9 H) ppm. 31P NMR (121 MHz, C6D6): δ = 108.6/
118.8 ppm. 19F NMR (376 MHz, C6D6): δ = –76.94/–73.49 ppm.
MS [ESI, H2O/CH3CN (1:1), 1% HCO2H]: m/z (%) = 628 (20) [M
+ H – 4CO]+, 656 (17) [M + H – 3CO]+, 684 (22) [M + H –
2CO]+, 712 (17) [M + H – CO]+, 740 (50) [M + H]+. HRMS (ESI):
calcd. for C32H24Co2F3NO5PS [M + H] 739.9729; found 739.9732.
Co2(µ-TMSC2H)(CO)4(µ-C27H20F6NOPS) (15a): According to the
general procedure, 15 (150 mg, 0.26 mmol), DABCO (45 mg,
0.40 mmol), and trimethylsilylacetylene dicobalt complex (112 mg,
0.29 mmol). The mixture was kept at 40 °C for 6 h and then heated
at 65 °C for 2 h. Flash chromatography (hexane/EtOAc, 95:5) af-
forded a mixture of diastereomers 15a (1:1, 132 mg, 57%) as a red
1
solid. IR (film): ν = 3059, 2955, 2043, 2011, 1988 cm–1. H NMR
˜
(400 MHz, C6D6): δ = 0.26/0.29 (2 s, 9 H, SiMe3), 3.91/3.95 (2 dd,
3
3
2JH,H = 16 Hz, JH,P = 5 Hz/2JH,H = 16 Hz, JH,P = 5 Hz, 1 H,
Synthesis of 4-(Trimethylsilyl)tricyclo[5.2.1.02,6]deca-4,8-dien-3-
CH2Ph), 4.73/4.77 (2 d, 2JH,H = 16 Hz/2JH,H = 16 Hz, 2 H, CH2Ph),
one[6]
5.71 (m, 4 H), 5.86/5.89 (2 d, JH,P = 11 Hz/3JH,P = 8 Hz, 1 H,
3
From 2a: Tetracarbonyl complex 2a (130 mg, 0.17 mmol), norbor-
nadiene (0.19 mL, 1.7 mmol), and toluene (4 mL) were charged in
a Schlenk flask under a nitrogen atmosphere and heated to 70 °C
with stirring. The reaction was monitored by TLC until disappear-
ance of the tetracarbonyl complex. The reaction was complete after
48 h. Purification by flash chromatography on SiO2 (hexane/
EtOAc, 95:5) yielded the desired product (30 mg, 72%).
HCϵCTMS), 6.42 (m, 6 H), 7.03–7.18 (m, with solvent peak, 11
H), 7.31 (d, J = 4 Hz, 2 H), 7.57 (m, 5 H), 7.84 (m, 2 H), 8.00 (m,
2 H), 8.10 (s.a, 4 H) ppm. 31P NMR (121 MHz, C6D6): δ = 116.9/
120.5 ppm. 19F NMR (376 MHz, C6D6): δ = –63.34/–63.47 ppm.
MS [ESI, H2O/CH3CN (1:1), 1% HCO2H]: m/z (%) = 824 (11) [M
+ H – 2CO]+, 852 (11) [M + H – CO]+, 880 (58) [M + H]+. HRMS
(ESI): calcd. for C36H31Co2F6NO5PSSi [M + H] 879.9992; found
879.9992.
From 16a: Tetracarbonyl complex 16a (60 mg, 0.08 mmol), norbor-
nadiene (0.08 mL, 0.81 mmol), and toluene (2 mL) were charged in
a Schlenk flask under a nitrogen atmosphere and heated to 70 °C
with stirring. The reaction was monitored by TLC until disappear-
ance of the tetracarbonyl complex. The reaction was complete after
65 h. Purification by flash chromatography on SiO2 (hexane/
EtOAc, 95:5) yielded the desired product (16 mg, 94%).
Co2(µ-TMSC2H)(CO)4(µ-C20H17F3NOPS) (16a): According to the
general procedure, 16 (125 mg, 0.296 mmol), DABCO (50 mg,
0.445 mmol), and trimethylsilylacetylene dicobalt complex
(125 mg, 0.326 mmol). The mixture was kept at 65 °C for 5 h. Flash
chromatography (hexanes/EtOAc, 95:5) afforded a mixture of dia-
stereomers 16a (1:1, 177 mg, 82%) as a red solid. IR (film): ν =
˜
Synthesis of 4-Phenyltricyclo[5.2.1.02,6]deca-4,8-dien-3-one[6]
2957, 2047, 2016, 1994 cm–1. 1H NMR (400 MHz, C6D6): δ = 0.34/
0.35 (2 s, 9 H, SiMe3), 4.42/4.64 (2 dd, 2JH,H = 18 Hz, 3JH,P = 8 Hz/
From 2b: Tetracarbonyl complex 2b (50 mg, 0.06 mmol), norborna-
diene (0.07 mL, 0.66 mmol), and toluene (2 mL) were charged in a
Schlenk flask under a nitrogen atmosphere and heated to 70 °C
with stirring. The reaction was monitored by TLC until disappear-
ance of the tetracarbonyl complex. The reaction was complete after
1 h. Purification by flash chromatography on SiO2 (hexane/EtOAc,
95:5) yielded the desired product (14 mg 95%).
3
2JH,H = 18 Hz, JH,P = 8 Hz, 1 H, CH2Ph), 4.76 (m, 2 H, CH2Ph),
5.97/6.08 (2 d, 3JH,P = 12 Hz/3JH,P = 9 Hz, 1 H, HCϵCTMS), 6.58
(m, 4 H), 6.75–6.81 (m, 9 H), 6.97 (m, 9 H), 7.21–7.26 (m, 2 H),
7.31–7.36 (m, 2 H), 7.60–7.70 (m, 4 H) ppm. 31P NMR (121 MHz,
C6D6): δ = 109.7/119.9 ppm. 19F NMR (376 MHz, C6D6): δ =
–77.02/–73.48 (d, J = 4/4 Hz) ppm. MS [ESI, H2O/CH3CN (1:1),
1% HCO2H]: m/z (%) = 680 (5) [M + H – 2CO]+, 708 (2) [M +
H – CO]+, 736 (15) [M + H]+, 753 (23) [M + NH4]+. HRMS (ESI):
From 16b: Tetracarbonyl complex 16b (35 mg, 0.05 mmol), norbor-
nadiene (0.05 mL, 0.47 mmol), and toluene (2 mL) were charged in
a Schlenk flask under a nitrogen atmosphere and heated to 70 °C
with stirring. The reaction was monitored by TLC until disappear-
ance of the tetracarbonyl complex. The reaction was complete after
calcd. for C29H28Co2F3NO5PSSi [M
735.9797.
+ H] 735.9805; found
Co2(µ–PhC2H)(CO)4(µ-C26H24NOPS) (2b): According to the gene-
[6]
ral procedure, 2·BH3 (182 mg, 0.41 mmol), DABCO (68 mg, 1 h. Purification by flash chromatography on SiO2 (hexane/EtOAc,
0.61 mmol), and phenylacetylene dicobalt complex (174 mg,
0.45 mmol). The mixture was kept at 65 °C for 4 h. Flash
chromatography (hexanes/EtOAc, 95:5) afforded a mixture of dia-
95:5) yielded the desired product (9 mg, 89%).
Supporting Information (see footnote on the first page of this arti-
cle): 1H and 13C NMR spectra for all new sulfinamides, PNSO
ligands, and cobalt complexes.
stereomers 2b (1:1, 260 mg, 82%) as a red solid. IR (film): ν =
˜
3047, 2038, 2007, 1982 cm–1. 1H NMR (400 MHz, C6D6): δ = 1.78/
2
3
1.76 (2 s, 3 H, CH3), 4.14/4.18 (2 dd, JH,H = 17 Hz, JH,P = 6 Hz/
2JH,H = 17 Hz, JH,P = 6 Hz, 1 H, CH2Ph), 4.75 (m, 2 H, CH2Ph),
3
Acknowledgments
5.92/6.00 (2 d, JH,P = 8 Hz/3JH,P = 10 Hz, 1 H, HCϵCPh), 5.95/
3
We thank the Ministerio de Ciencia e Innovación (MICINN,
CTQ2008-00763/BQU) and the Institute for Research in Biomedi-
cine (IRB Barcelona) for financial support. M. R. thanks Minis-
terio de Educación y Ciencia (MEC) for a fellowship.
6.05 (2 d, J = 8/8 Hz, 2 H), 6.54 (m, 10 H), 7.00–7.16 (m, with
solvent peak, 20 H), 7.63–7.81 (m, 12 H), 7.93 (m, 2 H) ppm. 31P
NMR (121 MHz, C6D6): δ = 114.8/117.8 ppm. MS [ESI, H2O/
CH3CN (1:1), 1% HCO2H]: m/z (%) = 650 (98) [M + H – 4CO]+,
678 (100) [M + H – 3CO]+, 706 (85) [M + H – 2CO]+, 734 (55) [M
+ H – CO], 762 (50) [M + H]+. HRMS (ESI): calcd. for
C38H31Co2NO5PS [M + H] 762.0325; found 762.0332.
[1] For recent applications of sulfoxides in metal catalysis, see: a)
R. Dorta, H. Rozenberg, L. J. W. Shimon, D. Milstein, J. Am.
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www.eurjic.org
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2009, 4446–4453

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[12]
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[14] IR spectra calculation (DFT/B3LYP) for a simplified Co2–al-
kyne–PNSO complex provided the same characteristic CO
stretching bands. The higher frequency band (A) corresponded
to the symmetric stretching of the four CO ligands. Spartan 06,
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[15] CCDC-732814 (for 16a) contains the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
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Received: June 11, 2009
Published Online: August 31, 2009
Eur. J. Inorg. Chem. 2009, 4446–4453
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4453