Perfluoroalkylphosphines and arsines obtained by Pd-catalyzed cross-coupling reaction with organoheteroatom stannanes

Article abstract of DOI:10.1016/j.jorganchem.2009.06.035

Pd-catalyzed cross-coupling reaction of organoheteroatom stannanes containing elements of the groups 15 (P, As) and 16 (Se) with perfluoroalkyl iodides (R_fI) was studied. Herein, a one-pot two-step reaction to form P-R_f, As-R_f

Full text of DOI:10.1016/j.jorganchem.2009.06.035

Journal of Organometallic Chemistry 694 (2009) 3425–3430
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Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Perfluoroalkylphosphines and arsines obtained by Pd-catalyzed cross-coupling
reaction with organoheteroatom stannanes
*
Mario N. Lanteri, Roberto A. Rossi, Sandra E. Martín
INFIQC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Medina Allende y Haya de la Torre, 5000 Córdoba, Argentina
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 15 April 2009
Received in revised form 22 June 2009
Accepted 23 June 2009
Available online 28 June 2009
Pd-catalyzed cross-coupling reaction of organoheteroatom stannanes containing elements of the groups
15 (P, As) and 16 (Se) with perfluoroalkyl iodides (RfI) was studied. Herein, a one-pot two-step reaction to
form P–Rf, As–Rf and Se–Rf bonds is reported. The stannanes n-Bu3SnZPhn (Z = P, As, Se; n = 1–2) were
generated in situ by the reaction of the PhnZꢀ anion with n-Bu3SnCl. The cross-coupling reactions of these
stannanes with RfI afforded C-heteroatom products, new perfluoroalkylarsines and perfluoroalkylsele-
nides in good yields (47–90%) and perfluoroalkylphosphines in moderate yields (15–48%).
Ó 2009 Elsevier B.V. All rights reserved.
Keywords:
Perfluoroalkylphosphines
Perfluoroalkylarsines
Pd-catalyzed reactions
Organoheteroatom stannanes
1. Introduction
Synthetic routes to perfluoroalkyl-substituted phosphines
R3-nP(Rf)n are not numerous. Some methods for the synthesis of
Organofluorine compounds have attracted particular interest in
recent years for displaying unique reactivities and selectivities and
for their promising applications in biological and material science
[1]. Among organofluorine compounds, those containing perfluoro-
alkyl groups (Rf) have became increasingly important; thus, it is re-
quired to develop new approaches to introducing these particular
groups.
Among the perfluoroalkyl compounds we found those contain-
ing P–Rf and As–Rf bonds especially interesting. Perfluoroalkyl-
substituted phosphines have lately drawn much attention due to
their potential applications as ligands in organometallic chemistry
[2]. Recently, a review describing the properties and synthesis of
fluorarylphosphine ligands was reported [3].
A wide range of tertiary phosphine ligands with substituents
such as alkyl or aryl groups was achieved because of their versatile
tuning abilities via steric and electronic properties [4]. However,
electron-poor or electroneutral phosphine ligands were less devel-
oped, probably due to the lack of methodologies for introducing
electron-withdrawing substituents. The lack of electroneutral
phosphine ligands was clearly shown in the evaluation of stereo-
electronic profile of known phosphine ligands [5]. Steric and elec-
tronic effects of some tertiary arsine ligands were also evaluated
[6]. Thus, the synthesis and application of new types of phosphines,
and also of arsines ligands with unusual stereoelectronic proper-
ties, are pursued as the main goals of the present study.
tris-perfluoroalkylphosphines have been reported [7]. Phosphines
bearing fluoroalkyl and fluorovinyl groups have been obtained from
LiRf and appropriate phosphorus precursors [8]. Only few examples
of aryl(bis)perfluoroalkylphosphines and diarylperfluoroalkylphos-
phines have been reported [8a,9]. For instance, the synthesis and
coordination chemistry studies of Ph2P(C2F5) were carried out,
and the perfluoroalkylphosphine was characterized as a sterically
bulky, electronically neutral ligand [2g–h,9d]. Alternatively, Ph2PRf
(Rf = C4F6, C6F13) were synthesized from PPh3 by the SRN1 mecha-
nism in HMPA [10]. It should be noted that, in general, the synthetic
methods reported have not worked effectively for perfluoroalkyl
chains longer than CF3 or C2F5. Therefore, a suitable synthesis for
a wide range of perfluoroalkylphosphines remains a challenging
task. Furthermore, perfluoroalkylarsines have scarcely been men-
tioned in the literature [7e–f,11]. Our primary objective centers
on the synthesis of arsines ligands in view of their growing applica-
tions as ligands in catalysis and on the fact that in many catalyzed
reactions they are more active as ligands than their analogous phos-
phines [12].
On the other hand, we have developed a versatile methodology
that allows for the C-heteroatom bond formation through a cross-
coupling Pd-catalyzed reaction of different electrophiles with
organoheteroatom stannanes R3SnZPhn (Z = P, As, Sb, Se) in one-
pot two-step reactions [13,14]. We have described the Pd-cata-
lyzed cross-coupling reaction of stannane n-Bu3SnSePh with
C8F17I and C10F21I [14]. This approach provides a convenient route
to obtain perfluoroalkylselenides; it being the first report of the Pd-
catalyzed reaction for heteroatom-Rf bond formation.
* Corresponding author. Tel.: +54 351 4334170; fax: +54 351 4333030.
E-mail address: martins@fcq.unc.edu.ar (S.E. Martín).
0022-328X/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2009.06.035

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M.N. Lanteri et al. / Journal of Organometallic Chemistry 694 (2009) 3425–3430
gands, solvents and catalysts, and of establishing the optimal reac-
[Pd] , L
ZPhn
SnBu3
1
PhnZRf
+
RfI
tion conditions. We selected C8F17I (2c) as a model substrate (Eq.
(1)); the results of Pd-catalyzed cross-coupling with n-Bu3SnPPh2
(1a) are shown in Table 1.
Toluene or DMF
Additive
2
3-5
[Pd], L
[O]
Rf = C4F9 (2a), C6F13 (2b), C8F19 (2c), C10F21 (2d)
n = 2 Z = P (1a), As (1b); n = 1 Z = Se (1c)
PPh2
C8F17
I
+
Ph2P(O)C8F17
SnBu3
ð1Þ
Toluene or DMF
Aditives
2c
3c
1a
Scheme 1.
The generation and subsequent use of stannanes 1 were in
agreement with the procedure previously reported by us for
the synthesis of tertiary phosphines [13a], arsines [13b,c] and
selenides [14]. Stannane 1a was generated in situ by the reac-
tion of Ph2Pꢀ anion with n-Bu3SnCl. Afterwards, the Pd-cata-
lyzed cross-coupling reaction of 1a with perfluoroalkyl iodide
2c was carried out, all in a one-pot two-step procedure. The
in situ generation of the stannanes eliminates the isolation
and purification of tin reagents. After oxidation, the reaction
afforded diphenylperfluoroalkyl phosphine oxide Ph2P(O)Rf
(Eq. (1)).
The initial conditions employed were the most effective ones
obtained in the Pd-catalyzed selenylation, (PPh3)2PdCl2/PPh3/CsF
in DMF at 120 °C) [14]. In these conditions, the cross-coupling
reaction of 1a with 2c only afforded <5% of 3c (entry 1, Table 1).
However, the conversion of the substrate was complete, and the
other product formed was C8F17H. It should be noted that in all
reactions herein reported, no vestige of remaining substrate was
found, and the other product achieved, in addition to the cross-
coupling one, was the reduced perfluoroalkane.
Only the introduction of Rf groups to olefinic and acetylenic car-
bons by the Pd-catalyzed reaction between organotin and perfluo-
roalkyl iodides (RfI) was reported [15]. In addition, b-
perfluoroalkyl-substituted alkyl iodide reacted with organostann-
anes in a Pd-catalyzed cross-coupling reaction [16]. The influence
of fluorine atoms in alkyl iodides in Pd-catalyzed coupling was also
investigated [17].
Our work focused on the development of a strategy to synthe-
size phosphines and arsines with Rf of type Ph2ZRf (Z = P, As) and
extend the previous studies with perfluoroalkylselenides. Herein,
we report our results on the Pd-catalyzed cross-coupling reaction
with RfI as electrophiles to obtain compounds containing P–Rf,
As–Rf and Se–Rf bonds (Scheme 1).
2. Results and discussion
In a previous work, we found for the first time that perfluoralkyl
iodides were viable electrophiles in the Pd-catalyzed cross-cou-
pling selenylation with n-Bu3SnSePh, and thereby we described
two examples of the synthesis of PhSeRf (Rf = C8F17, C10F21) [14].
Considering that compounds containing P–Rf and As–Rf bonds have
potential applications as ligands, we studied the Pd-catalyzed
cross-coupling of organoheteroatom stannanes n-Bu3SnPPh2 (1a)
and n-Bu3SnAsPh2 (1b) with RfI to achieve diphenylperfluoroalkyl-
phosphines and novel arsines.
2.2. Solvent
The yield could not be improved when the reaction was per-
formed in THF (entry 2, Table 1). However, when the reaction
was carried out under the same conditions in toluene at 80 °C, 3c
was achieved in 51% yield (entry 3, Table 1). Evidently, the non-po-
lar solvent was the most effective. This is the first report for the
synthesis of a perfluoroalkylphosphine with a perfluoroalkyl moi-
2.1. Optimization of the cross-coupling phosphination reaction
ety of eight
Ph2PC4F6 and Ph2PC6F13 [10] were obtained.
C atoms. Previously, only Ph2P(C2F5) [2g–h,9d],
The experiments have been performed with the objective of
gaining insight into the effect produced by different additives, li-
Table 1
Pd-catalyzed cross-coupling reaction with n-Bu3SnPPh2 (1a) and C8F17I (2c).a
Entry
Catalyst
Solvent
Ligand Pd:L (1:4)
Additive
Product 3c (%)b
1
2
3
4
5
6
7
8
(PPh3)2PdCl2
(PPh3)2PdCl2
(PPh3)2PdCl2
(PPh3)2PdCl2
(PPh3)2PdCl2
(PPh3)2PdCl2
(PPh3)2PdCl2
(PPh3)2PdCl2
(PPh3)2PdCl2
Pd2(dba)3
DMF
THF
PPh3
PPh3
PPh3
PPh3
–
PPh3
PPh3
PPh3
PPh3
PPh3
PPh3
PPh3
CsF
CsF
CsF
–
<5
10
51
40
11
14
14
39
32
6
<5
<2
<5
14
26
23
<2
<2
<2
16
<5
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene (80 °C)
Toluene (35 °C)
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
CsF
CuI
CsF, CuI
CsF
CsF
CsF
CsF
CsF
CsF
CsF
CsF
CsF
CsF
CsF
CsF
CsF
CsF
9
10
11
12
13
14
15
16
17
18
19
20
21
Pd(PPh3)4
[(
p-allyl)PdCl]2
Pd(OAc)2
PPh3
(PPh3)2PdCl2
(PPh3)2PdCl2
(PPh3)2PdCl2
(PPh3)2PdCl2
(PPh3)2PdCl2
[(p-allyl)PdCl]2
Pd(OAc)2
(PPh3)2PdCl2
AsPh3
P(2-furyl)3
P(o-tol)3
PCy3
P(t-Bu)2Me
P(t-Bu)2Me
P(t-Bu)2Me
P(t-Bu)2Biph
a
Reaction conditions: Ph2Pꢀ anion was prepared in liquid ammonia (300 mL) from PPh3 (1 mmol) and Na metal (2 mmol); n-Bu3SnCl (1 mmol) was then added. The cross-
coupling reaction was carried out with C8F17I (0.7 mmol), Pd catalyst (10 mol%, 0.07 mmol), L (Pd:L 1:4, 0.28 mmol), CsF (3 equiv., 2.1 mmol) and/or CuI (Pd:Cu 1:2) for 24 h at
reflux when toluene or THF was used, or at 120 °C with DMF.
b
GC yields (internal standard method). The informed yields represent at least the average of two reactions.

M.N. Lanteri et al. / Journal of Organometallic Chemistry 694 (2009) 3425–3430
3427
2.3. Fluoride and cooper(I) additives
2.6. Ligand
The effect of the additives on coupling reaction was studied
employing toluene as solvent. In this sense, Lewis-basic additives
have been shown to facilitate certain Stille reactions, presumably
by generating hypervalent stannane complexes [18]. Considering
the role of Lewis-basic additives this aspect and the fact that the
addition of Fꢀ ions could provide a more efficient cross-coupling
reaction [19], we used CsF as an activator of the organotin reagent.
When only extra PPh3 [20] was added to the reaction mixture,
the yields of 3c were lower than those found with PPh3/CsF (entry
4 versus 3, Table 1). When we carried out the reaction with CsF and
without additional ligand, 11% of 3c was achieved (entry 5, Table
1). In this case the reaction was retarded, indicating that the pres-
ence of ligand facilitated the reaction.
Another important development in Pd-catalyzed cross-coupling
reactions involves the use of Cu(I) as cocatalyst which improved
rates and yields [21]. In the presence of CuI, the cross-coupling
reaction with stannane 1a became less efficient (entry 6, Table
1). The copper negative effect could be attributed to the fact that
a ligand association mechanism may have taken place [21b,e].
On the other hand, it was reported that in many cases the com-
bination of CuI–CsF [22] significantly enhanced the Stille reaction.
In our system, the addition of CuI–CsF did not produce such effect;
instead, the reaction was retarded (entry 7, Table 1). Moreover, it
seems that the Cu effect was the predominant one.
The low reactivity of RfI could be ascribed to its reluctance to
participate in oxidative addition, the first step of the catalytic cycle,
where the structure of the ligand has a remarkable influence. In
view of this, we began by examining a variety of ligands.
When the coupling of 1a and 2c was carried out using
(PPh3)2PdCl2 and AsPh3 as the ligand, only a small amount of prod-
uct 3c was obtained (entry 14, Table 1). When extra AsPh3 was
added to the catalyst (PPh3)2PdCl2 (Pd:L 1:4), regardless of the
presence of PPh3 and their enhanced donicity, the influence of
the extra ligand could be noticed and the yields of the reaction
were lower than those with PPh3.
Additionally, P(2-furyl)3 and P(o-tol)3 proved to be less effective
than PPh3 in the coupling reaction (entries 15 and 16, Table 1).
These ligands, as well as AsPh3, are believed to enhance Stille cou-
plings by increasing the rate of transmetallation, which could im-
ply that the rate-limiting step in these cases might be oxidative
addition rather than transmetallation.
Significant progress has been made based on sterically demand-
ing electron-rich phosphines as the supporting ligand for the Stille
cross-coupling. With this possibility in mind, electron-rich PCy3
and P(t-Bu)2Me [25] were investigated as ligands that might pro-
mote oxidative addition by increasing the nucleophilicity of the
Pd(0) species. When the reaction of 1a and 2c was carried out with
these ligands using (PPh3)2PdCl2, essentially we obtained none of
the desired coupling product (entries 17 and 18, Table 1). Using
2.4. Substrate reduction
[(p-allyl)PdCl]2 as catalyst and P(t-Bu)2Me there was almost no
reaction (entry 19, Table 1). Under the same experimental condi-
tions with Pd(OAc)2 and P(t-Bu)2Me as ligand 3c was obtained in
only 16% yields (entry 20, Table 1). P(t-Bu)2Biph afforded also inef-
fective catalyst for the coupling reaction of 2c (entry 21, Table 1).
Although we examined a wide variety of conditions, the yields
of perfluoroalkylphosphine 3c were moderate. We could mention
two adverse effects on this particularly coupling reaction. One con-
cerns the reduction of the substrate by the stannane, which com-
peted with the phosphination reaction. It is also important to
notice that the final products of the cross-coupling reaction could
be ligands for the catalyst. These ligands could represent a problem
for the scope of the coupling reaction, since they could affect the
stability of the catalytic system.
With the aim of decreasing the amount of reduced product, we
carried out the reaction at 80 and 35 °C (entries 8 and 9, Table 1).
However, the reduction of the substrate was barely affected and
the yields of the coupling product were not high.
In previous research, we established the reductive power of the
stannylphosphine reagent in the Pd-catalyzed phosphination when
a nitro group was present as substituent [13a]. Thus, we performed
the reaction of 2c in the cross-coupling conditions without stann-
ane in toluene at 35 °C. In this reaction, 80% of substrate 2c was
recovered, indicating the participation of stannane in the reduction
of RfI. Moreover, when the relation substrate:stannane was modi-
fied to 1:2 in the phosphination, no reaction occurred, and the
reduction of substrate 2c was complete.
2.7. Pd-catalyzed coupling with Me3SiPPh2
2.5. Palladium source
In addition, we have studied the cross-coupling reaction cata-
lyzed by Pd(0) with Me3SiPPh2. Stille and coworkers have reported
an example of Pd-catalyzed coupling of Me3SiPPh2 with aryl ha-
lides to obtain aryldiphenylphosphine [26]. When we carried out
the one-pot two-step phosphination reaction with Me3SiPPh2 and
2c catalyzed by (PPh3)2PdCl2 in toluene and PPh3, the cross-cou-
pling product 3c was achieved in only 12% yield (Eq. (2)). No im-
proved yields were obtained in other conditions.
Despite that, for all Pd-catalyzed cross-coupling reactions with
organoheterostannanes studied, the best catalyst was (PPh3)2PdCl2
[13,14]; other sources of Pd were considered. Both Pd(0) catalysts,
Pd2(dba)3 and Pd(PPh3)4, with PPh3 as ligand were less effective
than (PPh3)2PdCl2 (entries 10 and 11, Table 1). A disadvantage of
Pd(0) complexes is that the ligands needed to stabilize Pd(0)
invariably have coordinating properties which hinder the forma-
tion of Pd(II) catalytic active species. The preligands associated
with the Pd catalyst will have differing degrees of coordination
ability, and they could also lead to the formation of different active
Pd(0) species [23]. Studies showed that the species formed from
Pd2(dba)3 and PPh3 is quite different from Pd(PPh3)4 [24].
(PPh3)2PdCl2
[O]
PPh2
PPh3
C8F17
I
+
Ph2P(O)C8F17
ð2Þ
SiMe3
Toluene
2c
12%, 3c
Having determined the best possible reaction conditions for the
Pd-catalyzed phosphination of 2c, we studied the reactivity of
other RfI (2a, 2b and 2d); the results of Pd-catalyzed cross-coupling
are shown in Table 2.
A significant influence of the perfluoroalky chain length was ob-
served in the phosphination reaction. When the reaction was car-
ried out under the optimal conditions found (PPh3)2PdCl2/PPh3/
CsF in toluene), and after oxidation of the phosphine obtained, only
22% and 15% yields of Ph2P(O)C4F9 (3a) and Ph2P(O)C6F13 (3b),
A Pd(II) catalyst is a feasible alternative to a Pd(0) catalyst, even
though this requires an additional preactivation step to generate
the active Pd(0) species. We evaluated [(p-allyl)PdCl]2 and
Pd(OAc)2 as Pd(II) catalysts. However, it should be noted that these
catalysts still have coordinating ligands that might interfere with
the formation of the active species. The effectiveness of these
two Pd sources was similar, and both were less effective than
(PPh3)2PdCl2 (entries 12 and 13, Table 1). Therefore, on the basis
of the experimental data, (PPh3)2PdCl2 was selected as Pd source.

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M.N. Lanteri et al. / Journal of Organometallic Chemistry 694 (2009) 3425–3430
Table 2
dides to obtain perfluoroalkylphosphines and arsines. There are
two different general conditions for the cross-coupling reaction
with perfluoroalkyl iodides. Optimization studies revealed that
the most favorable conditions for n-Bu3SnPPh2 and n-Bu3SnAsPh2
stannanes were (PPh3)2PdCl2/PPh3/CsF in toluene. They were also
the most effective conditions for stannane n-Bu3SnSePh, but in
DMF.
Despite that a competitive reduction of the substrates took
place, phosphines, arsines and selenides were obtained in good
to moderate yields. By this methodology new types of potential
perfluoroalkylarsine ligands were achieved. Particularly notewor-
thy is the fact the reaction worked for perfluoroalkyl chains longer
than four. These coupling reactions extended the use of organohet-
eroatom stannanes in the Stille reaction.
Pd-catalyzed cross-coupling with organoheteroatom stannanes 1 and RfI (2a–d) as
electrophile.a
Entry
Substrate
C4F9I
Stannane
Solvent
Product
Yield (%)b
1
2
3
4
5
6
7
8
n-Bu3SnPPh2
n-Bu3SnPPh2
n-Bu3SnPPh2
n-Bu3SnPPh2
n-Bu3SnAsPh2
n-Bu3SnAsPh2
n-Bu3SnAsPh2
n-Bu3SnAsPh2
n-Bu3SnSePh2
n-Bu3SnSePh2
n-Bu3SnSePh2
n-Bu3SnSePh2
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
DMF
Ph2P(O)C4F9 (3a)
Ph2P(O)C6F13 (3b)
Ph2P(O)C8F19 (3c)
Ph2P(O)C10F21(3d)
Ph2AsC4F9 (4a)
Ph2AsC6F13 (4b)
Ph2AsC8F19 (4c)
Ph2AsC10F21 (4d)
PhSeC4F9 (5a)
22
15
51
<5
47
43
65
48
28
37
70c
90c
C6F13
C8F19
I
I
C10F21
C4F9I
I
I
I
C6F13
C8F19
I
I
C10F21
9
C4F9I
C6F13
C8F19
10
11
12
I
I
DMF
DMF
DMF
PhSeC6F13 (5b)
PhSeC8F19 (5c)
PhSeC10F21 (5d)
C10F21
Reaction conditions: the PhnZꢀ anion (Z = P, As, Se; n = 2, 1) was prepared in
liquid ammonia (300 mL) from ZPh3 (1 mmol) or Ph2Se2 (0.5 mmol) and Na metal
(2 mmol); n-Bu3SnCl (1 mmol) was then added. The cross-coupling reaction was
carried out with RfI (0.7 mmol), (PPh3)2PdCl2 (10 mol%, 0.07 mmol), PPh3 (Pd:L 1:4,
0.28 mmol) and CsF (3 equiv., 2.1 mmol) for 24 h at reflux when toluene was used,
or at 120 °C with DMF.
a
4. Experimental
4.1. General methods
b
GC yields (internal standard method). The informed yields represent at least the
Gas chromatographic analyses were performed on a gas chro-
matograph with a flame ionization detector, and equipped with
average of three reactions.
c
Ref. [14].
the following columns: HP1 25 m ꢁ 0.20 mm ꢁ 0.25
lm column.
1H NMR, 13C NMR, 19F NMR and 31P NMR were conducted on a High
Resolution Spectrometer Bruker Advance 400, in CDCl3 as solvent.
Gas Chromatographic/Mass Spectrometer analyses were carried
out on a GC–MS QP 5050 spectrometer equipped with a VF-5ms,
respectively, were found (entries 1 and 2, Table 2). Moreover, with
perfluorodecyl iodide (2d) practically no product was achieved
(entry 4, Table 2), and the substrate was completely consumed.
The only product detected was the reduced perfluoroalkane. It
seems that the limit of the phosphination reaction is defined with
perfluorodecyl iodide and related to the substrate reduction.
30 m ꢁ 0.25 mm ꢁ 0.25
lm column. Melting points were per-
formed with an electrical instrument. The HRMS were recorded
at UCR Mass Spectrometry Facility, University of California, USA.
The AsPh3, PPh3, P(t-Bu)2Biph, P(o-tolyl)3, P(2-furyl)3, PCy3,
[HP(t-Bu)2Me]BF4 n-Bu3SnCl, (PPh3)2PdCl2, Pd2(dba)3, Pd(PPh3)4,
2.8. Pd-catalyzed cross-coupling arsination and selenylation with per-
fluoroalkyl iodides
[(p-allyl)PdCl]2, Pd(OAc)2, CuI, and RfI were commercially available
and used as received. CsF was dried under vacuum at 120 °C. All
solvents were analytical grade and distilled before use. Hexane
was HPLC grade. Toluene was distilled under nitrogen from Na-
benzophenone. DMF was stored under molecular sieves and then
distilled under reduced pressure with bubbling of nitrogen. All
reactions were carried out under atmosphere of nitrogen. Silica
gel (0.063–0.200 mm) was used in column chromatography.
To study this methodology further, we examined the Pd-cata-
lyzed arsination reaction with stannane n-Bu3SnAsPh2 (1b). The re-
sults of the cross-coupling reaction of perfluoroalkyl iodides 2 with
1b are shown in Table 2. The arsination reaction proceeded much
better than the phosphination reaction. Novel perfluoroakyldiphe-
nylarsines with perfluoroalkyl chains between four and ten C
atoms were obtained in moderate to good yields (entries 5–8, Ta-
ble 2). With organoarsine stannane it was observed that the chain
length had nearly no influence on the reactivity in the coupling
reaction. In these reactions the conversion was complete and per-
fluoroalkane was the other product found.
We also examined the Pd-catalyzed selenylation of C4F9I and
C6F13I. It is important to notice that there are not many synthetic
routes to perfluoroalkylselenides [27]. Recently, aryl and alkyl per-
fluoroalkyl selenides were obtained from diselenides in the pres-
ence of sodium hydroxymethanesulfinate from fair to good yield
[28].
4.2. Representative procedure forPd-catalyzed cross-coupling reaction
with organoheteroatom stannanes and perfluoroalkyl iodides
The following procedure for the reaction of n-Bu3SnAsPh2 (1b)
with perfluorooctyl iodide (2c) is representative of all cross-cou-
pling reactions. Into a three-necked, 500-mL, round-bottomed flask
equipped with a cold finger condenser charged with dry ice-etha-
nol, a nitrogen inlet, and a magnetic stirrer, approximately 400 mL
of ammonia previously dried with Na metal under nitrogen was
condensed. AsPh3 (1.0 mmol) and then 2 equiv. of Na metal
(2 mmol) in small pieces were added, waiting for bleaching be-
tween each addition. Following 20–30 min of the last addition,
Ph2Asꢀ anion was formed (clear orange-red solution), and n-
Bu3SnCl (1 mmol) was added slowly. The mixture was then stirred
for 5 min and the liquid ammonia allowed to evaporate. The evap-
oration left a solid white residue which was dissolved in dry tolu-
ene (12 mL). This solution was added via cannula and syringe into
a Schlenk tube. In the tube, CsF (3 equiv., 2.1 mmol) was previously
dried under vacuum at 120 °C for 3 h; after cooling at room tem-
perature, (PPh3)2PdCl2 (10 mol%, 0.07 mmol), PPh3 (Pd:L 1:4,
0.28 mmol), 2 (0.7 mmol) and toluene (3 mL) were added. When
the solution of 1 was added, the reaction mixture turned deep
brown. The reaction mixture was heated for 24 h in an oil bath.
Water was added to the cool reaction mixture and then extracted
three times with CH2Cl2 (30 mL each). After drying with anhydrous
The reaction of stannane 1c with RfI 2a and 2b was performed
in the best condition previously observed for C8F19I and C10F21
I
[14]. In these cases, it was found that although the reaction did
not proceed in toluene at 80 °C, using DMF as solvent and a higher
temperature, the selenylation reaction was allowed to proceed (en-
tries 11 and 12, Table 2). In this condition, we carried out the sel-
enylation with perfluoroalkyl iodides 2a and 2b, and obtained 28%
and 37% yields of PhSeC4F9 (5a) and PhSeC6F13 (5b) (entries 9 and
10, Table 2).
3. Conclusion
We reported a one-pot two-step Pd-catalyzed cross-coupling
reaction of organoheteroatom stannanes with perfluoroalkyl io-

M.N. Lanteri et al. / Journal of Organometallic Chemistry 694 (2009) 3425–3430
3429
MgSO4, product 3c was quantified by CG using the internal stan-
dard method, yielding 65% of the product.
ꢀ122.42–(ꢀ121.22) (m, CF2), ꢀ118.68–(ꢀ118.16) (m, CF2),
ꢀ117.51–(ꢀ117.11) (m, CF2), ꢀ108.86–(ꢀ108.40) (m, CF2),
ꢀ81.09–(ꢀ80.68) (m, CF3). MS: m/z (%): (MꢀF)+ 629 (1), 230 (12),
229 (100), 227 (41), 154 (10), 153 (7), 152 (14), 151 (9). HR MS
(EI): Calc. for C20H11OF17As 664.9749, found [M+OH]+ 664.9762.
The products were characterized by 1H NMR, 13C NMR, GC–MS
and HRMS. All these spectroscopic data agreed with those reported
in the literature for compounds 3a [10], 3b [10], 5a [28,27a], 5b
[28], 5c [28,14], and 5d [14].
4.7. (Perfluorodecyl)diphenylarsine (4d)
4.3. (Perfluorooctyl)diphenylphosphine oxide (3c)
Compound 4d was obtained according to the general proce-
dure. The product was isolated from the reaction mixture by
silica-gel column chromatography (hexane) to give 4b as colorless
oil. 1H NMR (CDCl3 ): 7.38–7.45 (6H, m), 7.57–7.63 (4H, m).
13C NMR (CDCl3): d 104.00–120.00 (C–F, partially overlapping mul-
tiplets), 128.94 (s), 130.05 (s), 130.85 (s), 134.42 (s). 19F NMR
(CDCl3 ): d ꢀ126.32–(ꢀ125.88) (m, CF2), ꢀ123.15–(ꢀ122.84) (m,
2CF2), ꢀ122.13–(ꢀ121.24) (m, 3CF2), ꢀ118.62–(ꢀ118.26) (m,
CF2), ꢀ117.44–(ꢀ116.93) (m, CF2), ꢀ108.80–(ꢀ108.43) (m, CF2).
MS: m/z (%): 729 (1), 230 (12), 229 (100), 227 (33), 154 (8), 153
Compound 3c was obtained according to the general procedure.
After the cross-coupling reaction and extraction, the organic phase
was oxidized with aqueous H2O2 (75 mL 40%) by following proce-
dure previously described [29]. The product was isolated from the
reaction mixture by silica-gel column chromatography (diethyl
ether/dichloromethane, 90:10 ? 30:70) to give 3c as a white solid.
1H NMR (CDCl3): d 7.56–7.61 (4H, m), 7.66–7.71 (2H, m), 8.00 (4H,
dd, 3J = 12.26 Hz, 4J = 7.28 Hz). 13C NMR (CDCl3): d 104.00–120.00
(C–F, partially overlapping multiplets), 125.85 (d, JC–P
104.63 Hz), 129.00 (d, JC–P = 12.81 Hz), 132.32 (d, JC–P = 9.82),
133.77 (d, JC–P = 3.00). 31P NMR (CDCl3 ):
24.66 (t, JP–C
69.31 Hz). 19F NMR (CDCl3 ):
ꢀ126.18–(ꢀ126.09) (m, CF2),
=
(6), 152 (10), 151 (7). HRMS
(EI): Calc. for C22H11OF21As
d
=
764.9685, found [M+OH]+ 764.9702.
d
ꢀ122.74 (s, CF2), ꢀ121.93 (s, CF2), ꢀ121.79 (s, CF2), ꢀ121.54 (s,
CF2), ꢀ118.21 (t, JF–F = 14.60, CF2), ꢀ118.03 (t, JF–F = 15.04, CF2),
ꢀ80.80 (t, JF–F = 9.62, CF3). MS: m/z (%): 601 (1), 202 (13), 201
(100), 183 (3), 154 (2), 153 (2), 152 (2), 131 (2). HRMS (EI): Calc.
for C20H11F17OP 621.0271, found [MꢀH]+ 621.0276. M.p.: 97.5–
98.7 °C.
Acknowledgements
We thank ACC, CONICET, FONCYT, and SECYT, Universidad Nac-
ional de Córdoba for their continuous support to our work. M.N.L.
thanks CONICET for the fellowship granted.
Appendix A. Supplementary material
4.4. (Perfluorobutyl)diphenylarsine (4a)
Supplementary data (general experimental details and proce-
dures, and characterization of 3c and 4a–d) associated with this
article can be found, in the online version, at doi:10.1016/
j.jorganchem.2009.06.035.
Compound 4a was obtained according to the general procedure.
The reaction mixture was purified by silica-gel column chromatog-
raphy (hexane) to give 4a as colorless oil. 1H NMR (CDCl3): d 7.42–
7.45 (6H, m), 7.59–7.62 (4H, m). 13C NMR (CDCl3): d 104.00–120.00
(C–F, partially overlapping multiplets), 128.96 (s), 130.12 (s),
130.91 (s), 134.53 (s). 19F NMR (CDCl3 ): d ꢀ(125.88–125.80) (m,
CF2), ꢀ118.34–(ꢀ118.26) (m, CF2), ꢀ108.92 (t, JF–F = 13.62, CF2),
ꢀ81.080 (t, JF–F = 9.66, CF3). MS: m/z (%): 448 (4), 429 (2), 230
(12), 229 (100), 227 (57), 154 (12), 153 (10), 152 (19), 151 (12).
HRMS (EI): Calc. for C16H11OF9As 464.8882, found [M+OH]+
464.9863.
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