Developing the kharasch reaction in aqueous media: Dinuclear group 8 and 9 catalysts containing the bridging cage ligand tris(1,2-dimethylhydrazino)- diphosphane

Article abstract of DOI:10.1002/ejic.200701132

The dinuclear complexes [{RuCl₂(η⁶-p-cymene)} ₂(μ-THDP)] (4) and [{MCl(η⁴-cod)} ₂(μ-THDP)] [M= Rh (5), Ir (6)], containing the bridging cage-type ligand tris(1,2-dimethylhydrazino) diphosphane (THDP),

Full text of DOI:10.1002/ejic.200701132

FULL PAPER
DOI: 10.1002/ejic.200701132
Developing the Kharasch Reaction in Aqueous Media: Dinuclear Group 8 and
9
Catalysts Containing the Bridging Cage Ligand Tris(1,2-dimethylhydrazino)-
diphosphane
[
a]
[a]
[b]
[c]
Alba E. Díaz-Álvarez, Pascale Crochet,* Maria Zablocka,* Carine Duhayon,
[a]
[c]
Victorio Cadierno, and Jean-Pierre Majoral*
Dedicated to Prof. José Gimeno on the occasion of his 60th birthday
Keywords: Phosphane ligands / Ruthenium / Rhodium / Iridium / Radical reactions
6
The dinuclear complexes [{RuCl
(
2
(η -p-cymene)}
2
(µ-THDP)]
by means of X-ray diffraction methods. All these complexes
have been found to be active catalysts for the atom-transfer
radical addition of bromotrichloromethane to olefins (Khar-
asch reaction) in heterogeneous aqueous media under mild
conditions (room temp.).
4
2
4) and [{MCl(η -cod)} (µ-THDP)] [M = Rh (5), Ir (6)], contain-
ing the bridging cage-type ligand tris(1,2-dimethylhydraz-
ino)diphosphane (THDP), have been synthesized in high
6
yields (89–95%) by treatment of dimers [{RuCl(µ-Cl)(η -p-
4
cymene)}
2
] (1) and [{M(µ-Cl)(η -cod)}
with one equivalent of THDP. The structure of the (η -arene)-
ruthenium(II) derivative 4 has been unequivocally confirmed
2
] [M = Rh (2), Ir (3)]
6
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2008)
aqueous-phase catalysis largely demonstrated.[2,3] During
the last decade, the cage-like water-soluble phosphane 1,3,5-
triaza-7-phosphaadamantane (PTA; see Figure 1) has
Introduction
A crucial factor in realizing a “green” chemical process
involves the choice of a safe, non-toxic, and cheap solvent.
[4]
[
1]
also received increasing attention and several ruthenium,
rhodium, and palladium PTA complexes have been shown
In this context, the development of organic transformations
in aqueous media has become one of the major corner-
stones in modern chemistry.[ Following this general trend,
there has been growing interest in the design of novel transi-
tion-metal catalysts for organic reactions in water in recent
[5]
to be promising catalysts in aqueous media. In this con-
2]
text, we have recently reported that the structurally related
trihydrazinophosphaadamantane ligand (THPA; see Fig-
[6]
ure 1) is also a suitable ligand for the solubilization of
[
3]
years, disclosing a wide variety of highly efficient and se-
[7]
transition-metal catalysts in water. In particular, several
lective synthetic approaches.[
2,3]
II
I
I
water-soluble Ru , Rh , and Ir THPA complexes could be
prepared and successfully applied to the catalytic isomeriza-
tion of allylic alcohols into carbonyl compounds, as well
as in the cycloisomerization of (Z)-enynols into furans, in
The introduction of hydrophilic ligands into the coordi-
nation sphere of a transition metal is probably the most
popular method for the preparation of water-soluble cata-
[
3]
lysts. Thus, a wide variety of functionalized phosphane
ligands containing highly polar sulfonated, hydroxyalkyl,
ammonium, phosphonium, carboxylate, carbohydrate, or
phosphonate groups are known and their effectiveness in
[7]
aqueous media.
[
a] Departamento de Química Orgánica e Inorgánica, Instituto
Universitario de Química Organometálica “Enrique Moles”
(
Unidad Asociada al CSIC), Universidad de Oviedo,
3
3071 Oviedo, Spain
Fax: +34-985-103-446
E-mail: pascale@fq.uniovi.es
Figure 1. Structure of the cage-like ligands PTA, THPA, and
THDP.
[b] Center of Molecular and Macromolecular Studies, The Polish
Academy of Sciences,
Sienkiewicza 112, 90363 Łód z´ , Poland
E-mail: zabloc@bilbo.cbmm.lodz.pl
With these precedents in mind, and continuing with our
studies aimed at discovering new catalytic systems, we
decided to explore the ability of the closely related
cage-type ligand tris(1,2-dimethylhydrazino)diphosphane
[c] Laboratoire de Chimie de Coordination CNRS, UPR 8241,
2
05 route de Narbonne, 31077 Toulouse, France
E-mail: majoral@lcc-toulouse.fr
786
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 786–794

Developing the Kharasch Reaction in Aqueous Media
P(NMeNMe) P (THDP; see Figure 1)[ to generate water-
8]
3
soluble transition-metal complexes. Remarkably, although
this ligand has been known since 1965 and can be easily
prepared at multigram-scale by treatment of commercially
available tris(dimethylamino)phosphane with 1,2-dimethyl-
hydrazine dihydrochloride (Scheme 1),[
9,10]
its coordination
chemistry has been scarcely developed. Thus, to the best of
our knowledge, the dinuclear compounds [{ML } (µ-
n 2
THDP)] [ML = W(CO)5,[
11]
Fe(CO)4,
[12]
Ni(CO) ,
[11]
n
3
[
13]
1
AlEt3 ] and the mononuclear derivative [Ni(CO) {κ -(P)-
3
[
11]
THDP}]
are the only THDP-metal complexes reported
till now in the literature. In addition, it is also interesting
to note that no reports on the involvement of this ligand in
homogeneous catalysis have been published.
Scheme 2. Synthesis of the dinuclear THDP-based complexes 4–6.
While for complexes 4 and 6 this resonance appears as a
simple singlet (δ = 120.9 and 98.9 ppm, respectively), for
P
the rhodium complex 5 a more complicated pattern is ob-
served (Figure 2). The spectrum shown in Figure 2 corre-
sponds to the AAЈ part of a AAЈXXЈ spin system due to
Scheme 1. Synthesis of the THDP ligand.
103
31
[15]
Rh– P couplings.
As previously observed in related
[
11–13]
[
{ML } (µ-THDP)] compounds,
the N-methyl groups
n 2
Thus, in the present work we describe the preparation of
the first ruthenium, rhodium, and iridium complexes con-
1
of the THDP ligand resonate in the H NMR spectra as a
3
4
6
pseudo-triplet with a | J
+ JP,H| separation of 11.6–
P,H
taining the THDP ligand, i.e. [{RuCl (η -p-cymene)} (µ-
2
2
1
4
4
12.0 Hz. The 13C{ H} NMR spectra show also a related
THDP)], [{RhCl(η -cod)} (µ-THDP)], and [{IrCl(η -
2
2
3
pattern for the N–Me carbons (ca. | J + JP,C| = 8.0 Hz).
P,C
cod)} (µ-THDP)] (cod = 1,5-cyclooctadiene), and their suc-
2
As expected for their symmetric structure, only one set of
cessful application to promote the catalytic atom-transfer
radical addition of bromotrichloromethane to olefins
resonances for the p-cymene (4) and 1,5-cyclooctadiene (5–
1
13
1
[14]
6) ligands is observed in the H and C{ H} NMR spectra
(Kharasch reaction) in aqueous media.
(see the Exp. Sect.).
Results and Discussion
6
Synthesis and Characterization of Complexes [{RuCl (η -p-
2
4
cymene)} (µ-THDP)] (4) and [{MCl(η -cod)} (µ-THDP)]
2
2
[
M = Rh (5), Ir (6)]
6
The dimeric ruthenium(II) complex [{RuCl(µ-Cl)(η -p-
cymene)} ] (1) readily reacts with one equivalent of
2
P(NMeNMe) P, in dichloromethane at room temperature,
3
6
to generate the dinuclear derivative [{RuCl (η -p-
2
cymene)} (µ-THDP)] (4) in which the cage-like diphos-
2
phane is acting as a bridging ligand (Scheme 2). Remarka-
Figure 2. The 31P{ H} NMR spectrum (121.5 MHz, CDCl
1
, 18 °C)
3
bly, all attempts to generate the mononuclear derivative
4
of complex [{RhCl(η -cod)}
2
(µ-THDP)] (5).
6
1
[
RuCl (η -p-cymene){κ -(P)-THDP}] failed, the reactions
2
6
leading to mixtures containing the dinuclear complex 4 and
The structure of the ruthenium(II) complex [{RuCl (η -
2
the unreacted diphosphane even when a large excess of p-cymene)} (µ-THDP)] (4) has been unambiguously con-
2
THDP (10 equiv.) was used. Similarly, treatment of dichlo- firmed by means of a single-crystal X-ray diffraction study.
4
romethane solutions of [{M(µ-Cl)(η -cod)} ] [M = Rh (2), An ORTEP view is shown in Figure 3; selected bond
2
Ir (3)] with THDP affords selectively the dinuclear species lengths and angles are listed in the caption. We note that
4
[
{MCl(η -cod)} (µ-THDP)] [M = Rh (5), Ir (6)] (Scheme 2) this compound represents the first example of a THDP
2
irrespective of the molar ratio used (from 1:1 to 1:10).
complex structurally characterized in the solid-state by X-
[
10]
Complexes 4–6, isolated as air- and moisture-stable sol- ray analysis.
It crystallizes in the orthorhombic space
ids in 89–95% yield, have been characterized by means of group Pbcn, half of the molecule in the asymmetric unit
1
31
1
13
1
multinuclear NMR spectroscopy [ H, P( H), and C( H)] being generated by symmetry. Each nitrogen atom is disor-
as well as elemental analyses, all data being fully consistent dered over two sites, namely N1/N11, N2/N12, and N3/
with the proposed formulations (details are given in the N13, with an occupancy of 80:20, respectively (representa-
3
1
1
Exp. Sect.). In particular, their P{ H} NMR spectra show tion and data given in Figure 3 correspond to the major
[
16]
the presence of only one signal indicative that both phos- occupancy).
An usual pseudooctahedral three-legged
phorus nuclei of THDP are in equivalent environments. piano-stool geometry around the metal is observed with
Eur. J. Inorg. Chem. 2008, 786–794
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
787

P. Crochet, M. Zablocka, J.-P. Majoral et al.
FULL PAPER
values of the interligand angles P(1)–Ru(1)–Cl(1), P(1)– years, organic peroxides and related radical initiators were
[
18]
Ru(1)–Cl(2), and Cl(1)–Ru(1)–Cl(2), and those between the commonly used to promote such a process. However, the
centroid of the arene ring C* and the legs, typical of a discovery that transition-metal complexes can efficiently
pseudo-octahedron. The Ru(1)–P(1) bond length of catalyze this transformation has increased the scope of its
2.3173(10) Å compares well with those previously reported synthetic applications, since they are able to completely sup-
for the related cage-like aminophosphane complexes press the oligomerization and telomerization side reactions
6
[17]
[
[
RuCl (η -p-cymene)(PTA)] [Ru–P 2.296(2) Å]
and usually observed when classical radical initiators are em-
2
6
[7]
[14]
RuCl (η -p-cymene)(THPA)] [Ru–P 2.294(2) Å]. It is also ployed. In particular, among the different metal catalysts
2
[
19]
[14b,20]
interesting to note that, when compared to the X-ray struc- reported to date, those based on copper,
nickel,
ture of the free ligand,[ the coordination of THDP to and specially ruthenium
10]
[14c,14d,21]
have provided the best
ruthenium does not alter significantly its geometry, the in- performance in terms of both selectivity and activity. It is
tra-ligand bond lengths (Ϯ0.05 Å) and angles (Ϯ10°) re- also interesting to note that, despite the great interest in
maining almost unchanged.
this catalytic transformation in synthesis, efforts devoted to
developing this reaction in water have been scarce.[
Thus, to the best of our knowledge, only the palladium-
based catalytic system [PdCl (NCPh) ]/dppf [dppf = 1,1Ј-
22–24]
2
2
bis(diphenylphosphanyl)ferrocene] has been applied in a
pure aqueous media, promoting efficiently the Kharasch
addition of BrCCl or n-C F I to several olefins under
3
6
13
22]
[
mild conditions (room temp.).
With all these precedents in mind we decided to explore
6
the ability of complexes [{RuCl (η -p-cymene)} (µ-THDP)]
2
2
4
(
4) and [{MCl(η -cod)} (µ-THDP)] (M = Rh (5), Ir (6)) to
2
6
act as catalysts for the Kharasch reaction in aqueous media.
2
Figure 3. ORTEP-type view of the structure of [{RuCl (η -p-
cymene)}
2
(µ-THDP)] (4) showing the crystallographic labeling The addition of bromotrichloromethane to 1-dodecene, to
scheme. Atoms labeled with an “a” are related to those indicated afford 3-bromo-1,1,1-trichlorotridecane, was used as a
by a crystallographic twofold symmetry axis. Hydrogen atoms have
model reaction (Scheme 3).
been omitted for clarity. Thermal ellipsoids are drawn at 30% prob-
ability level. Selected bond lengths [Å] and angles [°]: Ru(1)–P(1)
2
.3173(10), Ru(1)–Cl(1) 2.4043(12), Ru(1)–Cl(2) 2.4157(12), Ru(1)–
C* 1.721(1), P(1)–N(1) 1.681(4), P(1)–N(2) 1.663(4), P(1)–N(3)
1
.712(5), N(1)–C(11) 1.476(6), N(2)–C(12) 1.469(7), N(3)–C(13)
.453(6), N(1)–N(2a) 1.440(6), N(3)–N(3a) 1.458(8), C*–Ru(1)–
Scheme 3. The catalytic Kharasch addition of BrCCl
decene.
3
to 1-do-
1
P(1) 133.00(2), C*–Ru(1)–Cl(1) 125.03(1), C*–Ru(1)–Cl(2)
22.78(3), Cl(1)–Ru(1)–Cl(2) 90.29(4), Cl(1)–Ru(1)–P(1) 84.86(4),
Cl(2)–Ru(1)–P(1) 87.75(4), Ru(1)–P(1)–N(1) 114.33(15), Ru(1)–
1
Firstly, in order to determine the influence of the solvent,
P(1)–N(2) 117.48(16), Ru(1)–P(1)–N(3) 119.60(14), N(1)–P(1)– we explored the catalytic activity of the dinuclear rutheni-
N(2) 103.3(2), N(1)–P(1)–N(3) 98.9(2), N(2)–P(1)–N(3) 100.3(2),
P(1)–N(1)–N(2a) 114.3(3), P(1)–N(2)–N(1a) 116.1(3), P(1)–N(3)–
N(3a) 114.63(16), P(1)–N(1)–C(11) 119.5(3), P(1)–N(2)–C(12)
6
um(II) derivative [{RuCl (η -p-cymene)} (µ-THDP)] (4) in
2
2
water, methanol, acetonitrile, dichloromethane, tetrahydro-
furan, and toluene. In a typical experiment, 1-dodecene
1
24.2(4), P(1)–N(3)–C(13) 121.8(3). C* = centroid of the p-cymene
ring [C(1), C(2), C(3), C(4), C(5), C(6)].
(9 mmol), BrCCl (36 mmol), undecane (1 mmol; used as
3
internal standard), complex 4 (0.045 mmol; 0.5 mol-% with
respect to 1-dodecene; 1 mol-% in Ru) and 4 mL of the
appropriate solvent were introduced, under an inert
atmosphere, into a Schlenk tube and the mixture stirred at
room temperature for 3 h. Results are collected in Table 1.
As clearly shown in Table 1, the efficiency shown by com-
plex 4 is strongly dependent on the nature of the solvent
employed, the best results being obtained when polar and
protic solvents are used, i.e. water and methanol (66 and
Concerning the solubility of the dinuclear complexes 4–
, it should be noted that they are only sparingly soluble in
6
chlorinated solvents (CH Cl and CHCl ), acetonitrile and
2
2
3
tetrahydrofuran, being completely insoluble in alcohols and
water. Nevertheless, as discussed in the following section,
despite their insolubility in water they could be successfully
applied to the catalytic Kharasch-type addition of bromo-
trichloromethane to olefins in water.
6
2% yield, respectively; entries 1 and 2). In general, the use
of aprotic solvents, regardless of their polarity (entries 3–
), reduces considerably the catalytic activity of 4 (a similar
behavior has been observed in the absence of solvent; entry
). As expected, in the absence of complex 4 no addition of
6
Catalytic Activity of Complexes [{RuCl (η -p-cymene)} -
2
2
6
4
(
(
µ-THDP)] (4) and [{MCl(η -cod)} (µ-THDP)] [M = Rh
5), Ir (6)] in Atom-Transfer Radical Addition Processes
2
7
[
25,26]
The atom-transfer radical addition (ATRA) of polyhalo- BrCCl to 1-dodecene takes place (entries 8–9).
3
genated alkanes across a carbon–carbon double bond, in-
troduced for the first time by Kharasch and co-workers,
Once we had demonstrated that water is the solvent of
choice to perform this ATRA reaction efficiently, we also
[
18]
constitutes an effective method for the generation of C–C checked the catalytic activity of the dinuclear Group 9 spe-
and C–halogen bonds in a single operation.[ In the early cies [{MCl(η -cod)} (µ-THDP)] [M = Rh (5), Ir (6)] under
14]
4
2
788
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© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 786–794

Developing the Kharasch Reaction in Aqueous Media
Table 1. Kharasch addition of bromotrichloromethane to 1-do- dition of BrCCl to 1-dodecene (entry 7) confirming that
3
decene catalyzed by complex 4: Influence of the solvent.[
a]
metallic species are in all cases the real catalysts.
It is important to note that, under the reaction condi-
tions employed, complexes 4–6 are at first glance not solu-
ble neither in the aqueous phase nor in the organic phase
formed by the polyhalogenated alkane and the olefin, the
Entry Catalyst
Solvent Time Yield[b]
[
28]
reaction media being apparently heterogeneous.
In light
[
h]
[%]
of the possibilities offered by surfactants to perform cata-
lytic organic reactions in water, facilitating the solubility of
both the metal catalyst and the substrates, we decided to
6
(µ-THDP)] (4)[e]
(µ-THDP)] (4)
(µ-THDP)] (4)
(µ-THDP)] (4)
(µ-THDP)] (4)
(µ-THDP)] (4)
(µ-THDP)] (4)
1
2
3
4
5
6
7
8
9
[{RuCl
[{RuCl
[{RuCl
[{RuCl
[{RuCl
[{RuCl
[{RuCl
–
2
2
2
2
2
2
2
(η -cym)}
2
2
2
2
2
2
2
H
MeOH
MeCN
CH
THF
toluene
–
2
H O
toluene
2
O
3
3
3
3
3
3
3
3
3
66
62
13
53
19
34
36
0
6
(η -cym)}
[
29]
6
(η -cym)}
6
(η -cym)}
2
Cl
2
explore the Kharasch addition of BrCCl to 1-dodecene in
3
6
(η -cym)}
4
aqueous micelles using the iridium complex [{IrCl(η -
6
(η -cym)}
cod)} (µ-THDP)] (6) as a model. The commercially avail-
[
[
[
c]
6
2
(η -cym)}
d]
d]
able cetyltrimethylammonium bromide (CTABr) and so-
dium dodecyl sulfate (SDS) were used as surfactants, the
homogeneous reactions being performed in aqueous 0.05 
–
0
[
a] All the reactions were performed under N
temperature using 9 mmol of 1-dodecene, 36 mmol of BrCCl
2
atmosphere at room
[
30]
3
,
solutions of each. As shown in Table 2 (entries 8 and 9),
1
mmol of undecane (internal standard), 0.045 mmol of complex 4 both surfactants have a negative effect on the catalytic ac-
and 4 mL of the corresponding solvent. [b] Yield of 3-bromo-1,1,1-
trichlorotridecane determined by GC. [c] Reaction performed in
the absence of solvent. [d] Reaction performed in the absence of
catalyst. [e] cym = p-cymene.
tivity of complex 6, leading to the expected product in only
5
5–67% yield after 3 h (vs. 77% yield without a surfactant;
entry 3).
It is known that the catalytic activity of metal complexes
in Kharasch-type additions can be increased by adding
aqueous conditions. As shown in Table 2, both complexes
are active catalysts, showing higher performances to that of
the ruthenium derivative 4 (entries 2–3 vs. entry 1). Thus,
after 3 h 3-bromo-1,1,1-trichlorotridecane is selectively
formed in 81 and 77% yield, respectively.[ Interestingly,
the THDP-based complexes 4–6 are all much more efficient
than their dimeric precursors [{RuCl(µ-Cl)(η -p-cymene)} ]
1) and [{M(µ-Cl)(η -cod)} ] [M = Rh (2), Ir (3)] showing
[19a,22,31]
bases as additives.
Thus, in order to improve the
activity of complexes 4–6, some experiments have been per-
formed in the presence of diethylamine, triethylamine, and
pyridine. Once again, the aqueous addition of BrCCl to 1-
3
27]
dodecene was used as a model reaction employing 0.5 mol-
%
of complexes 4–6 and 0.5 equiv. of the amine (both of
6
2
them with respect to the olefin). As shown in Table 3, in
4
(
2
that the introduction of the THDP ligand into the coordi-
nation sphere of the metals plays a crucial role in attaining Table 3. Kharasch addition of bromotrichloromethane to 1-dode-
good conversions (entries 1–3 vs. 4–6). We have also cene in water: Influence of the additives on the catalytic activity of
complexes 4–6.[
a]
checked that THDP by itself is unable to promote the ad-
Table 2. Kharasch addition of bromotrichloromethane to 1-do-
decene in water: Influence of the metal catalyst.[
a]
Entry Catalyst
Additive Time
%
h] Yield[
b]
[
6
(µ-THDP)] (4)[c]
1
[{RuCl
2
(η -cym)}
2
–
3
7
3
3
3
3
3
3
7
3
3
3
7
3
3
66
83
58
57
0
81
80
89
93
49
77
90
95
78
40
Entry Catalyst
Time
% [
6
2
3
4
5
6
7
[{RuCl
[{RuCl
[{RuCl
2
2
2
(η -cym)}
2
(µ-THDP)] (4)
2
(µ-THDP)] (4)
2
(µ-THDP)] (4)
Et
Et
pyridine
–
Et
Et
2
NH
N
b]
[h]
Yield
6
(η -cym)}
3
6
(µ-THDP)] (4)[e]
(µ-THDP)] (5)
(µ-THDP)] (6)
6
1
2
3
4
5
6
7
8
9
[{RuCl
2
(η -cym)}
2
3
3
3
3
3
3
3
3
3
66
81
77
48
40
49
0
(η -cym)}
4
4
[{RhCl(η -cod)}
2
[{RhCl(η -cod)}
2
(µ-THDP)] (5)
2
(µ-THDP)] (5)
2
(µ-THDP)] (5)
4
4
[{IrCl(η -cod)}
[{RuCl(µ-Cl)(η -cym)}
[{Rh(µ-Cl)(η -cod)}
[{Ir(µ-Cl)(η -cod)}
P(NMeNMe)
[{IrCl(η -cod)}
[{IrCl(η -cod)}
2
6
[{RhCl(η -cod)}
2
NH
N
4
2
] (1)
] (2)
] (3)
P (THDP)
[{RhCl(η -cod)}
3
4
2
4
4
2
8
9
10
[{RhCl(η -cod)}
2
(µ-THDP)] (5)
(µ-THDP)] (6)
(µ-THDP)] (6)
pyridine
–
Et
[
[
[
c]
4
3
[{IrCl(η -cod)}
[{IrCl(η -cod)}
2
d]
d]
4
4
2
(µ-THDP)] (6)/SDS
(µ-THDP)] (6)/CTABr
67
55
2
2
NH
4
2
4
1
1
1
2
[{IrCl(η -cod)}
[{IrCl(η -cod)}
2
(µ-THDP)] (6)
(µ-THDP)] (6)
Et
pyridine
3
N
[
a] All the reactions were performed under N
temperature using 9 mmol of 1-dodecene, 36 mmol of BrCCl
mmol of undecane (internal standard), 0.045 mmol of the corre-
sponding metal complex, and 4 mL of water. [b] Yield of 3-bromo-
,1,1-trichlorotridecane determined by GC. [c] Reaction performed
2
atmosphere at room
4
2
3
,
1
[a] All the reactions were performed under N
temperature using 9 mmol of 1-dodecene, 36 mmol of BrCCl
1
1 mmol of undecane (internal standard), 0.045 mmol of the corre-
sponding metal complex, 4 mL of water, and 4.5 mmol of the addi-
tive when appropriate. [b] Yield of 3-bromo-1,1,1-trichlorotri-
decane determined by GC. [c] cym = p-cymene.
using 0.5 mol-% of the THDP ligand in the absence of any metallic
source. [d] 4 mL of a 0.05  solution of the appropriate surfactant
in water was used as solvent. [e] cym = p-cymene.
Eur. J. Inorg. Chem. 2008, 786–794
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
789

P. Crochet, M. Zablocka, J.-P. Majoral et al.
4
FULL PAPER
the case of the ruthenium catalyst 4 none of the additives the rhodium derivative [{RhCl(η -cod)} (µ-THDP)] (5) al-
2
allowed us to improve its efficiency, the attained yields be- beit a longer reaction time is required (88% yield after 44 h;
[
33]
ing in all cases lower to that obtained in the absence of entry 11).
In contrast, for the
rhodium 5 and iridium 6 derivatives improvement in the
additive (entries 2–4 vs. entry 1).[
32a]
Table 4. Catalytic Kharasch addition of bromotrichloromethane to
several olefins in water.
[a]
catalytic activity was observed by using Et N and Et NH,
respectively (entry 7 vs. entry 5 and entry 10 vs. entry 9).
3
2
Entry
Olefin
Catalyst
Time [h]
% Yield[b]
[
32b]
Thus, under these optimized conditions 3-bromo-1,1,1-
1
2
3
4
5
6
7
8
9
1-octene
1-octene
1-octene
cyclooctene
cyclooctene
cyclooctene
4-penten-2-ol
4-penten-2-ol
4-penten-2-ol
styrene
4
6
6
6
84
92
71
5/Et
6/Et
4
3
2
N
NH
trichlorotridecane can be generated in 93 (using 5/Et N)
3
and 95% (using 6/Et NH) yield after stirring the hetero-
2
24
24
24
20
20
20
44
44
44
6 (46:54)
90 (46:54)
88 (46:54)
11 (60:40)
91 (60:40)
92 (60:40)
0
geneous mixture for 7 h at room temperature (83% yield
can be attained with the ruthenium catalyst 4 after 7 h).
It is commonly accepted that the key step in the Khar-
asch reaction is the pseudo-oxidative addition of the haloal-
kane onto the metal complex [Equation (1)].[14] Therefore,
5/Et
6/Et
4
5/Et
6/Et
4
3
2
N
NH
3
2
N
NH
1
0
we could argue that the benefic effect of the amines in the 11
styrene
styrene
5/Et N
6/Et
88
53
3
I
I
case of Rh and Ir could be associated with the elimination 12
2
NH
of traces of HX (X = Cl, Br), presumably generated during
2
[a] All the reactions were performed under N atmosphere at room
the radical process, which could give rise to catalytically temperature using 9 mmol of the appropriate olefin, 36 mmol of
III
III
BrCCl , 1 mmol of undecane (internal standard), 0.045 mmol of
the corresponding metal complex, 4 mL of water, and 4.5 mmol of
the additive when appropriate. [b] Yields determined by GC (dia-
stereomeric ratios are given in brackets).
inactive Rh and Ir species via competitive oxidative ad-
dition. We note that the catalytic activity of complexes 4–6
is completely suppressed in the presence of the radical scav-
enger BHT (2,6-di-tert-4-methoxyphenol), confirming the
involvement of free radicals in the catalytic cycle.
3
R–X + [M]n+ i R + X–[M]
·
(n+1)+
(1)
The aqueous Kharasch addition of bromotrichlorometh- Figure 4. Structure of the products generated from cyclooctene and
4
-penten-2-ol.
ane to other olefinic substrates (1-octene, cyclooctene, 4-
penten-2-ol, and styrene) using the optimized catalytic sys-
It is well-known that Kharasch addition of polyhalogen-
tems, i.e. the RuII complex 4 by itself, the Rh complex 5
I
ated alkanes to 1,6-diolefins leads usually to cyclization
products.
ether with BrCCl , in water and in the presence of our opti-
I
associated with Et N, and the Ir derivative 6 associated
[22,23,34]
3
In accord with this, treatment of diallyl
with Et NH, has also been explored. Selected results are
2
3
collected in Table 4. In general, the rhodium- and iridium-
based systems were found to be much more efficient and
versatile than the ruthenium one, which showed a good per-
formance only when 1-octene was used as the substrate,
leading to 3-bromo-1,1,1-trichlorononane in 84% yield af-
ter 6 h (entry 1). For this particular olefin, the best results
were obtained using the rhodium derivative 5 (92% yield
mized catalytic systems, leads in all cases to the selective
formation of 3-(bromomethyl)-4-(2,2,2-trichloroethyl)tetra-
hydrofuran (Scheme 4). Once again, the best results were
obtained using the rhodium catalyst 5 which cleanly affords
the tetrahydrofuran, as a mixture of diastereoisomers (ratio
ca. 85:15), in 74% yield after only 3 h. We note also that,
as previously observed with cyclooctene and 4-penten-2-ol,
the diastereoselectivity of the process is not dependent on
the metallic fragment employed.
I
after 6 h). This catalyst, along with the Ir complex 6, was
also highly efficient for the radical addition of BrCCl to
3
cyclooctene and the functionalized olefin 4-penten-2-ol gen-
erating 1-bromo-2-(trichloromethyl)cyclooctane and 4-
bromo-6,6,6-trichlorohexan-2-ol, respectively in more than
88% yield after 20–24 h (entries 5–6 and 8–9). Under sim-
ilar reaction conditions very low yields (6–11%) were at-
tained using 4 (entries 4 and 7). The addition of BrCCl3
across the C=C bond of cyclooctene and 4-penten-2-ol gen-
erates products that contain two stereogenic centers (see
Figure 4), the formation of mixtures of two diastereoiso-
mers being in all cases observed. Interestingly, the three
catalytic systems employed (based on Ru , Rh , and Ir )
lead to the same selectivity, i.e. cis/trans ratio = 46:54 for
cyclooctene and 60:40 for 4-penten-2-ol, suggesting that the
stereochemistry-controlling step does not occur in the coor-
3
Scheme 4. Catalytic Kharasch addition of BrCCl to diallyl ether.
II
I
I
Conclusions
In summary, the first ruthenium, rhodium, and iridium
dination sphere of the metal. Finally, in the case of styrene complexes containing the cage-type ligand tris(1,2-dimeth-
6
(
entries 10–12), good results were exclusively obtained using ylhydrazino)diphosphane, namely [{RuCl (η -p-cymene)} -
2 2
790
www.eurjic.org
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 786–794

Developing the Kharasch Reaction in Aqueous Media
4
(
(
µ-THDP)] (4) and [{MCl(η -cod)} (µ-THDP)] [M = Rh
=
C
8.0 Hz, NCH
3
), 70.4 and 109.5 (br., =CH) ppm.
2
(729.29): calcd. C 36.23, H 5.80, N 11.52;
2
5), Ir (6)], have been synthesized. Despite their insolubility
in water, all these species have been found to be active cata-
lysts for the atom-transfer radical addition of bromotrichlo- 6: Yield 0.323 g (89%). P{ H} NMR (CDCl ): δ = 98.9 (s) ppm.
romethane to olefins (Kharasch reaction) in aqueous me-
22
H42Cl
2
N
6
P
2
Rh
found C 36.33, H 5.90, N 11.41.
3
1
1
3
1
H NMR (CDCl
J
3
): δ = 1.78–2.77 (m, 16 H, CH
P,H| = 12.0 Hz, 18 H, NCH ), 3.46 and 5.34 (br., 4 H
each, =CH) ppm. C{ H} NMR (CDCl ): δ = 28.7 and 34.0 (s,
2
), 3.01 (virtual t,
|3
+
4
J
dia. Among the THDP-based complexes employed, the
P,H
3
1
3
1
4
rhodium derivative [{RhCl(η -cod)} (µ-THDP)] (5) associ-
3
2
2
3
CH
2
), 38.8 (virtual t, | JP,C
00.7 (s, =CH) ppm. C22 42Cl
.66, N 9.26; found C 29.28, H 4.54, N 9.12.
+
J
P,C| = 8.0 Hz, NCH
3
), 53.4 and
ated with triethylamine was found to be the most active and
versatile, representing a rare example of an efficient rho-
dium catalyst for the Kharasch reaction.[
1
4
H
2 2 6 2
Ir N P (907.91): calcd. C 29.10, H
35]
General Procedure for the Catalytic Kharasch Reactions: All the sol-
vents and reactants used in the catalytic processes were employed
freshly distilled and deoxygenated. The catalyst precursor
Experimental Section
(
0.045 mmol of dinuclear species or 0.090 mmol of mononuclear
complexes), the olefin (9 mmol), bromotrichloromethane
36 mmol), undecane (1 mmol), the appropriate solvent (4 mL)
and, when indicated, the additive (4.5 mmol of Et N, Et NH, or
General: The manipulations were performed under an atmosphere
of dry nitrogen using vacuum-line and standard Schlenk tech-
niques. Organic solvents were dried by standard methods and dis-
tilled under nitrogen before use. All reagents were obtained from
commercial suppliers with the exception of compounds
(
3
2
pyridine) were introduced at room temperature into a Schlenk tube.
The mixture was then stirred at room temperature for the indicated
time, the course of the reaction being monitored by regular sam-
pling and GC or GC/MSD analysis. All the yield values given in
the tables are the average of two runs. In all cases, differences be-
tween the two measures were within Ϯ3%. The identity of the re-
sulting product, which can be isolated in pure form after extraction
with CH Cl and subsequent purification by column chromatog-
2 2
raphy over silica gel (using hexane/diethyl ether mixtures), was con-
firmed by comparison of their NMR spectroscopic data with those
[
9]
6
(1),[36] [{M(µ-
P(NMeNMe)
3
P,
[M
[{RuCl(µ-Cl)(η -p-cymene)}
2
]
4
[37]
[38]
6
Cl)(η -cod)}
2
[
]
=
Rh (2),
Ir (3) ], [RuCl
2
(η -p-cy-
17]
6
[7]
mene)(PTA)] , and [RuCl
2
(η -p-cymene)(THPA)] which were
prepared by following the method reported in the literature. The
C,H,N elemental analyses were carried out with a Perkin–Elmer
2400 microanalyzer. Infrared spectra were recorded with a Perkin–
Elmer 1720-XFT spectrometer. NMR spectra were performed with
1
31
a Bruker DPX300 instrument at 300 MHz ( H), 121.5 MHz ( P),
13
or 75.4 MHz ( C) using SiMe
4
or 85% H
3
PO
4
as standards. Dis-
[39]
reported in the literature, i.e. 3-bromo-1,1,1-trichlorotridecane,
torsionless enhancement by polarization transfer (DEPT) experi-
ments were carried out for all the compounds reported in this pa-
per. GC and GC/MSD measurements were made with the Hewlett–
Packard HP6890 (Supelco Beta-Dex 120 column; 30 m, 250 µm)
system and an Agilent 6890N gas chromatograph coupled to a 5973
[40]
3
-bromo-1,1,1-trichlorononane,
1-bromo-2-(trichloromethyl)-
(1-bromo-3,3,3-trichloropropyl)benzene , and 3-
[41]
[42]
cyclooctane,
[34c]
(
bromomethyl)-4-(2,2,2-trichloroethyl)tetrahydrofuran,
with the
TM
exception of the unknown compound 4-bromo-6,6,6-trichloro-
hexan-2-ol which was fully characterized. This compound was iso-
lated as a white solid in 86% yield (using the iridium-based cata-
lytic system), its analytical and spectroscopic data being as follows:
mass detector (HP-1MS column; 30 m, 250 µm), respectively.
6
Synthesis of Complex [{RuCl
2
(η -p-cymene)}
2
(µ-THDP)] (4): A
] (1) (0.184 g, 0.300 mmol)
P (0.085 g, 0.360 mmol) in dichloromethane
20 mL) was stirred at room temperature for 1 h. The solvent was
6
6 10 3
C H BrCl O (284.41): calcd. C 25.34, H 3.54; found C 25.49, H
solution of [{RuCl(µ-Cl)(η -p-cymene)}
and P(NMeNMe)
(
2
–
1
3
.61. IR (Nujol): ν˜ = 3337 (νOH) cm . NMR spectroscopic data for
3
1
3
the major diastereoisomer: H NMR (CDCl
3
): δ = 1.22 (d, JH,H
CHOH), 3.21
part A of an AB system of d, JH,H = 15.7, JH,H = 5.2 Hz, 1 H,
=
6
(
.4 Hz, 3 H, Me), 1.90 and 2.12 (m, 1 H each, CH
2
then removed under reduced pressure to give an orange solid resi-
due, which was washed twice with a hexane/diethyl ether mixture
2
3
2
3
3
1
1
CH CCl ), 3.46 (part B of an AB system of d, J
H,H H,H
= 15.7, J
(20 mL, 1:1) and dried in vacuo. Yield 0.239 g (94%). P{ H}
2
3
1
2 3
= 5.4 Hz, 1 H, CH CCl ), 4.06 (m, 1 H, CHOH), 4.54 (m, 1 H,
NMR (CDCl
3
): δ = 120.9 (s) ppm. H NMR (CDCl
], 2.29 (s, 6 H, CH
3
): δ = 1.40 [d,
), 3.00 (virtual
1
3
1
3
3
CHBr) ppm. OH signal not observed. C{ H} NMR (CDCl ): δ
J
H,H = 6.9 Hz, 12 H, CH(CH
3
)
2
3
3
3
4
2
= 23.8 (s, Me), 46.5 (s, CHBr), 48.3 (s, CH CHBr), 62.8 (s,
CH CCl ), 65.3 (s, CHOH), 97.0 (s, CCl ) ppm. NMR spectro-
2 3 3
t, | JP,H + JP,H| = 11.6 Hz, 18 H, NCH
3
), 3.07 [sept, JH,H = 6.9 Hz,
], 5.29 and 5.62 (br., 4 H each, CH of cymene) ppm.
C{ H} NMR (CD Cl ): δ = 17.5 (s, CH ), 22.4 [s, CH(CH ],
0.7 [s, CH(CH ], 37.5 (br., NCH ), 88.1 and 91.1 (s, CH of cy-
Ru
848.60): calcd. C 36.80, H 5.46, N 9.90; found C 36.98, H 5.31, N
.79.
2
3 2
H, CH(CH )
1
1
3
1
scopic data for the minor diastereoisomer: H NMR (CDCl ): δ =
)
2
3
2
2
3
3
3
1
.08 (d,
CH CHOH), 3.29 (part A of an AB system of d,
H,H = 4.8 Hz, 1 H, CH CCl ), 3.41 (part B of an AB system of
H,H = 5.6 Hz, 1 H, CH CCl ), 4.06 (m, 1 H,
CHOH), 4.28 (m, 1 H, CHBr) ppm. OH signal not observed.
JH,H = 6.4 Hz, 3 H, Me), 2.08 and 2.17 (m, 1 H each,
3
3
)
2
3
2
JH,H = 16.0,
mene), 100.2 and 112.5 (s, C of cymene) ppm. C26
H46Cl
4
N
6
P
2
2
2
3
J
2
3
(
9
d, 2JH,H = 16.0,
3
J
2
3
4
Synthesis of Complexes [{MCl(η -cod)}
6)]: A solution of the appropriate dimer [{M(µ-Cl)(η -cod)}
) (0.400 mmol) and P(NMeNMe) P (0.109 g, 0.460 mmol) in
2
(µ-THDP)] [M = Rh (5), Ir
1
3
1
C{ H} NMR (CDCl
CH CHBr), 62.4 (s, CH
CCl ) ppm.
3
): δ = 22.7 (s, Me), 45.2 (s, CHBr), 48.1 (s,
4
(
3
2
] (2–
2
2
CCl ), 66.0 (s, CHOH), 97.1 (s,
3
3
3
dichloromethane (20 mL) was stirred at room temperature for 3 h.
The solvent was then removed under reduced pressure to give a
yellow solid residue, which was washed twice with a hexane/diethyl
ether mixture (20 mL, 1:1) and dried in vacuo.
1
Catalytic Reactions in the Presence of Surfactants: These catalytic
reactions were carried out following a similar procedure replacing
the solvent by a 0.05  aqueous solution (4 mL) of sodium dodecyl
sulfate (SDS) or cetyltrimethylammonium bromide (CTABr).
5
: Yield 0.277 g (95%). 31P{ H} NMR (CDCl
3
): δ = 112.8 (AAЈ
): δ = 2.07–
1
part of a AAЈXXЈ spin system) ppm. H NMR (CDCl
3
X-ray Crystal Structure Determination of Complex 4: Crystals suit-
able for X-ray diffraction analysis were obtained by slow diffusion
of n-pentane into saturated solutions of complex 4 in dichlorometh-
ane. The most relevant crystal and refinement data are collected in
3
4
2
.45 (m, 16 H, CH
NCH ), 3.91 and 5.60 (br., 4 H each, =CH) ppm. C{ H} NMR
3 2
CDCl ): δ = 28.2 and 33.3 (s, CH ), 38.6 (virtual t, | JP,C + JP,C|
2
), 3.01 (virtual t, | JP,H + JP,H| = 12.0 Hz, 18 H,
13
1
3
2
3
(
Eur. J. Inorg. Chem. 2008, 786–794
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
791

P. Crochet, M. Zablocka, J.-P. Majoral et al.
FULL PAPER
Table 5. Intensity data were collected at low temperature with an
Xcalibur Oxford Diffraction diffractometer using a graphite-mono- [1] See for example: a) P. T. Anastas, J. C. Warner in Green Chem-
chromated Mo-K radiation source (λ = 0.71073 Å) and equipped
istry: Theory and Practice, Oxford University Press, Oxford,
998; b) P. T. Anastas, T. C. Williamson in Green Chemistry:
α
1
with an Oxford Cryosystems Cryostream Cooler Device. A total of
4866 reflections were collected of which 5326 were independent.
Multiscan absorption corrections were applied (Tmin–max = 0.52–
Frontiers in Benign Chemical Synthesis and Processes, Oxford
University Press, New York, 1998; c) A. S. Matlack in Introduc-
tion to Green Chemistry, Marcel Dekker, New York, 2001; d)
M. Lancaster in Handbook of Green Chemistry and Technology
3
[
43]
0
.96).
The structures were solved by direct methods using
and refined by full-matrix, least-squares procedures on
[
44]
SIR92,
(
Eds.: J. H. Clark, D. J. Macquarrie), Blackwell Publishing, Ab-
[
45]
F using CRYSTALS. Atomic scattering factors were taken from
the International Tables for X-ray Crystallography.[ Non-hydro-
gen atoms were refined anisotropically. The H atoms were refined
using a riding model. The crystallographic plots were made with
ingdon, 2002; e) M. Lancaster in Green Chemistry: An Intro-
ductory Text, RSC Editions, London, 2002; f) P. T. Anastas,
M. M. Kirchhoff, Acc. Chem. Res. 2002, 35, 686–694.
46]
[2] See for example: a) C. J. Li, Chem. Rev. 1993, 93, 2023–2035;
b) A. Lubineau, J. Auge, Y. Queneau, Synthesis 1994, 741–760;
c) C. J. Li, T. H. Chan in Organic Reactions in Aqueous Media,
John Wiley & Sons, New York, 1997; d) F. M. da Silva, J. Jones,
Quim. Nova 2001, 24, 646–657; e) J. B. F. N. Engberts, M. J.
Blandamer, Chem. Commun. 2001, 1701–1708; f) U. M.
Lindström, Chem. Rev. 2002, 102, 2751–2772; g) C. J. Li, Acc.
Chem. Res. 2002, 35, 533–538; h) C. J. Li, Chem. Rev. 2005,
[
47]
PLATON.
Table 5. Crystal data and structure refinement details for 4.
Chemical formula
2 26 46 6 4 2 2 2
Ru C H N Cl P ·2CH Cl
Mol. mass
T [K]
Wavelength [Å]
Crystal system
Space group
Crystal size [mm]
a [Å]
b [Å]
c [Å]
α [°]
1018.45
180(2)
0.71073
orthorhombic
Pbcn
0.50ϫ0.25ϫ0.03
13.691(3)
12.247(2)
23.701(5)
90
1
05, 3095–3166; i) C. K. Z. Andrade, L. M. Alves, Curr. Org.
Chem. 2005, 9, 195–218; j) C. J. Li, L. Chen, Chem. Soc. Rev.
2
006, 35, 68–82; k) L. Chen, C. J. Li, Adv. Synth. Catal. 2006,
3
48, 1459–1484; l) C. I. Herrerías, X. Yao, Z. Li, C. J. Li, Chem.
Rev. 2007, 107, 2546–2562.
[
3] See for example: a) P. Kalck, F. Monteil, Adv. Organomet.
Chem. 1992, 34, 219–284; b) W. A. Herrmann, C. W.
Kohlpaintner, Angew. Chem. Int. Ed. Engl. 1993, 32, 1524–
1544; c) I. T. Horváth, F. Joó (Eds.), Aqueous Organometallic
β [°]
90
Chemistry and Catalysis, Kluwer, Dordrecht, 1995; d) F. Joó,
A. Kathó, J. Mol. Catal. A 1997, 116, 3–26; e) B. Cornils, W. A.
Herrmann (Eds.), Aqueous-Phase Organometallic Catalysis:
Concepts and Applications, Wiley-VCH, Weinheim, 1998; f)
B. E. Hanson, Coord. Chem. Rev. 1999, 185–186, 795–807; g)
F. Joó, Aqueous Organometallic Catalysis, Kluwer, Dordrecht,
γ [°]
Z
V [Å ]
90
4
3
3974.2(14)
1.702
1.409
2056
2.82 to 29.08
–18ՅhՅ18
–
3
ρcalcd. [gcm ]
–1
µ [mm ]
F(000)
θ range [°]
Index ranges
2
001; h) N. Pinault, D. W. Bruce, Coord. Chem. Rev. 2003, 241,
1
–25; i) C. A. M. Afonso, L. C. Branco, N. R. Candeias,
P. M. P. Gois, N. M. T. Lourenço, N. M. M. Mateus, J. N.
Rosa, Chem. Commun. 2007, 2669–2679.
–
–
16ՅkՅ12
32ՅlՅ32
[4] IUPAC name: 1,3,5-triaza-7-phosphatricyclo[3.3.1.13,7]decane.
[5] For reviews see: a) A. D. Phillips, L. Gonsalvi, A. Romerosa,
F. Vizza, M. Peruzzini, Coord. Chem. Rev. 2004, 248, 955–993;
b) V. Cadierno, P. Crochet in Advances in Organometallic
Chemistry Research (Ed.: K. Yamamoto), Nova Science Pub-
lishers, New York, 2007, chapter 2, pp. 37–65.
Completeness to θmax
99.8%
34866
5326 (Rint = 0.072)
Number of data collected
Number of unique data
Number parameters/restraints
Refinement method 2
Goodness of fit on F
202/3
Full-matrix least-squares on F
1.1188
0.0325
0.0373
[
a]
R
1
[IϾ3σ(I)]
[6] IUPAC name: 2,4,10-trimethyl-1,2,4,5,7,10-hexaaza-3-phos-
[
a]
3,7
wR
2
[IϾ3σ(I)]
phatricyclo[3.3.1.1 ]decane.
–3
Largest diff. peak and hole [e·Å ] 0.90 and –0.67
= {Σ[w(F 2 2)2]/Σ[w(F ) ]}1/2.
a] R = Σ(|F | – |F |)/Σ|F |; wR – F
o
[7] A. E. Díaz-Álvarez, P. Crochet, M. Zablocka, C. Duhayon, V.
Cadierno, J. Gimeno, J. P. Majoral, Adv. Synth. Catal. 2006,
2 2
[
1
o
c
o
2
o
c
348, 1671–1679.
[
8] IUPAC name: 2,3,5,6,7,8-hexamethyl-2,3,5,6,7,8-hexaaza-1,4-
CCDC-659558 (for 4) contains supplementary crystallographic
data. These data can be obtained free of charge from The Cam-
bridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
diphosphabicyclo[2.2.2]octane.
[9]
a) D. S. Payne, H. Nöth, G. Henniger, Chem. Commun. (Lon-
don) 1965, 327–329; b) R. Goetze, H. Nöth, D. S. Payne, Chem.
Ber. 1972, 105, 2637–2653; c) H. Nöth, R. Ullmann, Chem.
Ber. 1974, 107, 1019–1027.
[
10] The X-ray crystal structure of this diphosphane has been re-
ported: W. van Doorne, G. W. Hunt, R. W. Perry, A. W.
Cordes, Inorg. Chem. 1971, 10, 2591–2594.
Acknowledgments
[
11] a) R. D. Kroshefsky, J. G. Verkade, J. R. Pipal, Phosphorus Sul-
fur 1979, 6, 377–389; b) R. D. Kroshefsky, J. G. Verkade, Phos-
phorus Sulfur 1979, 6, 397–405.
A. E. D.-A., P. C., and V. C. thank the Spanish Ministerio de Edu-
cación y Ciencia (MEC) [Projects CTQ2006-08485/BQU and Con-
solider Ingenio 2010 (CSD2007-00006)] and the Gobierno del Prin-
cipado de Asturias (FICYT Project IB05-035) for financial sup-
port. V. C. thanks MEC and the European Social Fund for a
[
[
[
12] R. M. Matos, J. G. Verkade, J. Braz. Chem. Soc. 2003, 14, 71–
75.
13] S. F. Spangenberg, H. H. Sisler, Inorg. Chem. 1969, 8, 1004–
“
Ramón y Cajal” contract. M. Z. thanks the Polish Ministry of
Science and Information Society Technologies for financial support
Grant no. 3T09A 158 29). A. E. D.-A., M. Z., and J. P. M. thank
1006.
14] For recent reviews and accounts on the Kharasch reaction see:
a) J. Iqbal, B. Bhatia, N. K. Nayyar, Chem. Rev. 1994, 94, 519–
564; b) R. A. Gossage, L. A. van de Kuil, G. van Koten, Acc.
Chem. Res. 1998, 31, 423–431; c) L. Delaude, A. Demonceau,
(
the Laboratoire Européen Associé (LEA), Toulouse-Lodz for fin-
ancial support.
792
www.eurjic.org
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 786–794

Developing the Kharasch Reaction in Aqueous Media
A. F. Noels, Top. Organomet. Chem. 2004, 11, 155–171; d) K.
Severin, Curr. Org. Chem. 2006, 10, 217–224.
[27] Note that, as observed with the ruthenium catalyst, the use of
an organic solvent such as toluene produces a lower activity
than that obtained in water (46% and 42% yield after 3 h using
5 and 6, respectively). The 1:1 and 1:2 adducts between the 1,4-
[
15] This spectrum has been simulated with the gNMR v.4.1 soft-
3
1
ware (Adept Scientific plc), leading to JP,P and JRh,P coupling
3
constants of 72 and 206 Hz, respectively. A similar JP,P value
3
cyclooctadiene ligand and BrCCl , i.e. bromo(trichloromethyl)-
1
83
(
75 Hz) could be extracted from the W satellite peaks in the
cyclooctene and dibromobis(trichloromethyl)cyclooctane, have
not been detected during the analyses of the crude reaction
mixtures by means of NMR or GC/MSD techniques.
[28] Solubilization of trace amounts of the catalysts in the organic
phase can not be totally discarded.
3
1
1
P{ H} spectrum of the related dinuclear species [{(CO)
W}
2
(µ-THDP)] (see ref.[ ). The JRh,P value is also in accord
11b]
1
5
with those usually observed in phosphane-rhodium(I) com-
1
plexes. As an example, JRh,P = 199 Hz has been reported for
4
the tris(dimethylamino)phosphane derivative [RhCl(η -
[29]
See for example: P. Alvarez, M. Bassetti, J. Gimeno, G. Man-
cini, Tetrahedron Lett. 2001, 42, 8467–8470 and references cited
therein.
2 3
cod){P(NMe ) }]: C. J. Elsevier, B. Kowall, H. Kragten, Inorg.
Chem. 1995, 34, 4836–4839.
[
16] Data corresponding to the minor occupancy are the following
[
30] The critical micelle concentrations of CTABr and SDS are
(
bond lengths in Å and angles in deg): P(1)–N(11) 1.610(14),
P(1)–N(12) 1.826(16), P(1)–N(13) 1.718(18), N(11)-N(13a)
.48(2), N(12)–N(12a) 1.51(3), N(11)–C(11) 1.468(9), N(12)–
C(12) 1.510(9), N(13)–C(13) 1.531(9), Ru(1)–P(1)–N(11)
–3
–3
8
ϫ10  and 9ϫ10 , respectively, the use of 0.05  solu-
tions of these surfactants assuring therefore the correct forma-
tion of micelles: a) J. H. Fendler, E. J. Fendler, Catalysis in Mi-
cellar and Macromolecular Systems, Academic Press, New
York, 1975; b) K. Furton, A. Norelus, J. Chem. Educ. 1993, 70,
1
117.9(5), Ru(1)–P(1)–N(12) 112.3(5), Ru(1)–P(1)–N(13)
120.0(6), N(11)–P(1)–N(12) 101.8(7), N(11)–P(1)–N(13)
100.8(8), N(12)–P(1)–N(13) 101.2(6), P(1)–N(11)–N(13a)
119.3(10), P(1)–N(12)–N(12a) 109.4(4), P(1)–N(13)–N(11a)
108.0(10), P(1)–N(11)–C(11) 124.9(10), P(1)–N(12)–C(12)
111.9(9), P(1)–N(13)–C(13) 116.8(11).
2
54–257. Under these reaction conditions the organometallic
catalyst is completely soluble in the aqueous phase.
[
31] See for example: a) J. Tsuji, K. Sato, H. Nagashima, Chem.
Lett. 1981, 1169–1170; b) J. Tsuji, K. Sato, H. Nagashima, Tet-
rahedron 1985, 41, 393–397; c) R. G. Gasanov, F. M. Dolgu-
shin, A. I. Yanovsky, Z. S. Klemenkova, B. V. Lokshin, P. V.
Petrovsky, M. I. Rybinskaya, Russ. Chem. Bull. 1997, 46, 1125–
[
[
17] C. S. Allardyce, P. J. Dyson, D. J. Ellis, S. L. Heath, Chem.
Commun. 2001, 1396–1397.
18] a) M. S. Kharasch, H. Engelmann, F. R. Mayo, J. Org. Chem.
1130.
1937, 2, 288–302; b) M. S. Kharasch, E. V. Jensen, W. H. Urry,
[26]
[
32] a) As commented in ref.
the real catalytically active species
Science 1945, 102, 128; c) M. S. Kharasch, W. H. Urry, E. V.
Jensen, J. Am. Chem. Soc. 1945, 67, 1626; d) M. S. Kharasch,
E. V. Jensen, W. H. Urry, J. Am. Chem. Soc. 1946, 68, 154–155;
e) M. S. Kharasch, E. V. Jensen, W. H. Urry, J. Am. Chem. Soc.
derived from complex 4 are presumably generated by dissoci-
ation of the p-cymene ligand. The competitive coordination of
the amines to ruthenium can therefore be evoked to explain
these results. This inhibiting effect is strongly marked in the
case of pyridine whose great ability to act as a two-electron
donor ligand is well known. b) The coordinating effect of
pyridine is also reflected in the catalytic behavior of 5–6, the
experiments performed in the presence of pyridine leading to
remarkably lower yields (entry 8 vs. entry 5 and entry 12 vs.
entry 9).
1
947, 69, 1100–1105; f) M. S. Kharasch, O. Reinmuth, W. H.
Urry, J. Am. Chem. Soc. 1947, 69, 1105–1110.
[
19] For recent examples, see: a) A. Zazybin, O. Osipova, U. Khus-
nutdinova, I. Aristov, B. Solomonov, F. Sokolov, M. Babash-
kina, N. Zabirov, J. Mol. Catal. A 2006, 253, 234–238; b) W. T.
Eckenhoff, T. Pintauer, Inorg. Chem. 2007, 46, 5844–5846; c)
J. M. Muñoz-Molina, A. Caballero, M. M. Díaz-Requejo, S.
Trofimenko, T. R. Balderraín, P. J. Pérez, Inorg. Chem. 2007,
[
[
[
33] As shown in Table 4 (entry 10), the ruthenium complex 4 was
3
completely inactive in the Kharasch addition of BrCCl to sty-
46, 7428–7435.
6
rene. We suggest that the ability of styrene to act as a η -arene
[
20] For recent examples, see: a) V. Pandarus, D. Zargarian, Chem.
Commun. 2007, 978–980; b) V. Pandarus, D. Zargarian, Orga-
nometallics 2007, 26, 4321–4334.
ligand blocking the metal may be responsible for this behavior.
This supposition is in complete accord with the observations
[26]
made in ref.
.
[
21] For recent examples, see: a) L. Quebatte, K. Thommes, K. Se-
verin, J. Am. Chem. Soc. 2006, 128, 7440–7441; b) A. Richel,
A. Demonceau, A. F. Noels, Tetrahedron Lett. 2006, 47, 2077–
34] See for example: a) S.-K. Khan, C.-H. Park, S.-G. Kim, W.-T.
Oh, Bull. Korean Chem. Soc. 1991, 12, 716–717; b) T. Naka-
mura, H. Yorimitsu, H. Shinokubo, K. Oshima, Synlett 1998,
2081.
1
351–1352; c) B. C. Gilbert, W. Kalz, C. I. Lindsay, P. T.
[
22] D. Motoda, H. Kinoshita, H. Shinokubo, K. Oshima, Adv.
McGrail, A. F. Parsons, D. T. E. Whittaker, J. Chem. Soc., Per-
kin Trans. 1 2000, 1187–1194.
Synth. Catal. 2002, 344, 261–265.
[
23] We note that complexes [Mn (CO) ] and [MnBr(CO) ] have
2
10
5
35] The involvement of rhodium complexes in catalytic Kharasch
reactions has been scarcely documented: a) S. Murai, R. Sugise,
N. Sonoda, Angew. Chem. Int. Ed. Engl. 1981, 20, 475–476; b)
C. J. Cable, H. Adams, N. A. Bailey, J. Crosby, C. White, J.
Chem. Soc., Chem. Commun. 1991, 165–166; c) L. Quebatte,
R. Scopelleti, K. Severin, Angew. Chem. Int. Ed. 2004, 43,
been found to be active catalysts under biphasic H
2
2 2
O/CH Cl
conditions: N. Huther, P. T. McGrail, A. F. Parsons, Eur. J.
Org. Chem. 2004, 1740–1749.
[
[
24] Et B-promoted Kharasch-type additions in pure aqueous me-
3
dia have also been reported. See for example: H. Yorimitsu, H.
Shinokubo, S. Matsubara, K. Oshima, K. Omoto, H. Fujim-
oto, J. Org. Chem. 2001, 66, 7776–7785.
1520–1524.
[36] M. A. Bennett, T. N. Huang, T. W. Matheson, A. K. Smith, In-
org. Synth. 1982, 21, 74–78.
25] It is interesting to note that, under the same reaction condi-
tions (water/room temp./1 mol-% of Ru), the catalytic activity
[
37] a) G. Giordano, R. H. Crabtree, Inorg. Synth. 1979, 19, 218–
220; b) G. Giordano, R. H. Crabtree, Inorg. Synth. 1990, 28,
88–90.
of complex 4 is higher than that of the water-soluble PTA-
6
based derivative [RuCl
3
2
(η -p-cymene)(PTA)] (36% yield after
6
h) and comparable to that of [RuCl
2
(η -p-cymene)(THPA)]
[
[
[
38] J. L. Herde, J. C. Lambert, C. V. Senoff, Inorg. Synth. 1974, 15,
(
65% yield after 3 h).
18–20.
[
26] The efficiency of complex 4 is strongly affected when the cata-
lytic aqueous reactions are performed in the presence of free
p-cymene showing that the real catalytically active species are
generated by dissociation of the arene ligand (50% and 0%
yield after 3 h when a p-cymene/Ru ratio of 20 and 100, respec-
tively, is employed).
39] K. Maruoka, H. Sano, Y. Fukutani, H. Yamamoto, Chem.
Lett. 1985, 1689–1692.
40] D. J. Burton, L. J. Kehoe, J. Org. Chem. 1970, 35, 1339–1342.
[41] J. G. Traynham, T. M. Couvillon, J. Org. Chem. 1967, 32, 529–
532.
Eur. J. Inorg. Chem. 2008, 786–794
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
793

P. Crochet, M. Zablocka, J.-P. Majoral et al.
FULL PAPER
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Published Online: December 20, 2007
794
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© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 786–794