(η5-halogenocyclohexadienyl)Mn(CO)3 complexes: Halogen substitution by arene derivatives

Article abstract of DOI:10.1021/om000831d

Unprecedented coupling reactions on (η⁵-chlorocyclohexadienyl)tricarbonyl manganese complexes with arenes create a new carbon-carbon bond on the conjugated system, keeping intact the η⁵-chlorocyclohexadienyl moiety; thus, the removal of the exo hydrogen bond of the sp³ CH₂ group yields efficiently new cationic (η⁶-arene) manganese complexes which cannot be prepared directly from the free arene.

Full text of DOI:10.1021/om000831d

Organometallics 2001, 20, 1901-1903
1901
(η5-Ha logen ocycloh exa d ien yl)Mn (CO)3 Com p lexes:
Ha logen Su bstitu tion by Ar en e Der iva tives
Damien Prim,† Audrey Auffrant,† Franc¸oise Rose-Munch,† Eric Rose,*,† and
J acqueline Vaissermann‡
Laboratoire de Synthe`se Organique et Organome´tallique , UMR CNRS 7611, Universite´ Pierre
et Marie Curie, Tour 44-1er e´tage, 4 Place J ussieu, 75252 Paris Cedex 05, France, and
Laboratoire de Chimie Inorganique et Mate´riaux Mole´culaires, ESA CNRS 7071,
Universite´ Pierre et Marie Curie, Bat. F, 4 Place J ussieu, 75252 Paris Cedex 05, France
Received September 26, 2000
Summary: Unprecedented coupling reactions on (η5-
Sch em e 1
chlorocyclohexadienyl)tricarbonyl manganese complexes
with arenes create a new carbon-carbon bond on the
conjugated system, keeping intact the η5-chlorocyclo-
hexadienyl moiety; thus, the removal of the exo hydrogen
bond of the sp3 CH2 group yields efficiently new cationic
(η6-arene) manganese complexes which cannot be pre-
pared directly from the free arene.
The activation of arenes by coordination to transition
metals is a well-established phenomenon. The manga-
nese-mediated functionalization of arenes is particularly
attractive because of the very high electrophilicity of the
relevant complexes which undergo high-yield nucleo-
philic additions.1 The corresponding tricarbonyl(η5-
cyclohexadienyl)manganese complexes are stable and
relatively inert.2 Only a few examples of the reactivity
of their carbon π-system are described in the literature
with stabilized nucleophiles3 or hydrides.4-6
As part of our current studies on organochromium
complexes1a,6b and on cross-coupling reactions,7 we
have shown the potentiality of bimetallic activation
under smooth reaction conditions at room temperature,
which avoids side product formation and decomplex-
ation.8 We now report the use of Pd2(dba)3 in the pres-
ence of AsPh3 for the arylation of neutral (η5-chlorocy-
clohexadienyl)Mn(CO)3 complexes through a regioselec-
tive substitution of the chlorine atom by an aryl group.
This unprecedented functionalization of an η5-halogeno-
cyclohexadienyl complex occurred without loss of the
tricarbonylmanganese entity. This allowed us to stress
the potentiality of these new substituted η5-cyclohexa-
dienyl complexes, particularly in the formation of
substituted cationic (η6-arene) manganese complexes.
(η5-Chlorocyclohexadienyl)Mn(CO)3 complexes were
readily prepared by hydride addition to variously sub-
stituted cationic (η6-chlorobenzene)Mn(CO)3 complexes
1 according to Scheme 1:4,6,9 mixtures of two regioiso-
mers ortho and meta with respect to Cl were obtained
in various ratios and were separated by silica gel
chromatography column, whereas addition of hydride
to (η6-ortho- or para-chloroanisole)Mn(CO)3 complex
affords a single regioisomer, 2e or 2c, respectively.6a
Complex 2a coupled with tributylphenyltin using 10%
10
Pd2(dba)3 and 35% AsPh3 in freshly distilled and
* Corresponding author. E-mail: rose@ccr.jussieu.fr.
† Laboratoire de Synthe`se Organique et Organome´tallique , UMR
CNRS 7611.
degassed DMF at room temperature for 23 h, affording
tricarbonyl(1-phenyl η5-cyclohexadienyl)manganese com-
plex 4a in 52% yield (Table 1, entry 1). Control experi-
ments conducted under the same conditions but in the
absence of the catalyst gave no arylation product (Table
1, entry 2).
These first observations prompted us to extend this
strategy by using various substituted starting complexes
2 as well as heterocyclic tributyltin reagents. The results
are gathered in Table 1. Several points warrant com-
ments: thienyltributyltin behaved similarly and reacted
with complex 2a to give the expected coupling product
5a (Table 1, entry 3). Furthermore, the reaction path
seems to be independent of the nature and the position
of the starting substitution pattern (Table 1, entries
‡ Laboratoire de Chimie Inorganique et Mate´riaux Mole´culaires,
ESA CNRS 7071.
(1) (a) Rose-Munch, F.; Gagliardini, V.; Renard, C.; Rose, E. Coord.
Chem. Rev. 1998, 178-180, 249. (b) Mc Daniel, K. F. Comprehensive
Organometallic Chemistry II; Abel, E. W., Stone, F. G. A., Wilson, G.,
Eds.; 1995; Vol. 6, pp 93-107.
(2) Kane-Maguire, L. A. P.; Honig, E. D.; Sweigart, D. A. Chem. Rev.
1984, 84, 524.
(3) Roell, B. C.; Mc Daniel, K. F.; Vaughan, W. S.; Macy, T. S.
Organometallics 1993, 12, 224.
(4) Brookhart, M.; Lukacs, A. Organometallics 1983, 2, 649; J . Am.
Chem. Soc. 1984, 106, 4161.
(5) Ittel, S. D.; Whitney, J . F.; Chung, Y. K.; Williard, P. G.;
Sweigart, D. A. Organometallics 1988, 7, 1323, and references therein.
(6) (a) Balssa, F.; Gagliardini, V.; Rose-Munch, F.; Rose, E. Orga-
nometallics 1996, 15, 4373. (b) Rose-Munch, F.; Rose, E. Curr. Org.
Chem. 1999, 3, 445.
(7) (a) Prim, D.; Kirsch, G. J . Chem. Soc., Perkin Trans. 1 1994,
2603. (b) Plyta, Z. F.; Prim, D.; Tranchier, J . P.; Rose-Munch, F.; Rose,
E. Tetrahedron Lett. 1999, 40, 6769. (c) Tranchier, J . P.; Chavignon,
R.; Prim, D.; Auffrant, A.; Plyta, Z. F.; Rose-Munch, F.; Rose, E.
Tetrahedron Lett. 2000, 41, 3607.
(9) Pauson, P. L.; Segal, J . A. J . Chem. Soc., Dalton Trans. 1975,
1677; J . Chem. Soc., Dalton Trans. 1975, 1683.
(10) Farina, V.; Krishnan, B.; Marshall, D. R.; Roth, G. P. J . Org.
Chem. 1993, 58, 5434.
(8) Prim, D.; Tranchier, J . P.; Rose-Munch, F.; Rose, E.; Vaisser-
mann, J . Eur. J . Inorg. Chem. 2000, 5, 901.
10.1021/om000831d CCC: $20.00 © 2001 American Chemical Society
Publication on Web 04/12/2001

1902 Organometallics, Vol. 20, No. 10, 2001
Communications
Ta ble 2. Stille Cou p lin g Rea ction s of Com p lexes 3
entry
3
R
yield (%) after 20 h
F igu r e 1.
1
2
3
3a
3b
3d
H
5-Me
1-Me
8a (58)
8b (30)
8d (43)
Ta ble 1. Stille Cou p lin g Rea ction s of Com p lexes 2
Sch em e 2
entry
2
R
Ar
time (h)
23
yield (%)
1
2
3
4
5
6
7
2a
2a
2a
2b
2b
2c
2d
H
H
H
Ph
Ph
Th
Ph
Th
Th
Th
4a (52)
-
5a (51)
4b (45)
5b (48)
5c (78)
5d (53)
no catalyst
18
24
20
20
20
4-Me
4-Me
4-OMe
2-Me
(Table 2) with a thienyltin derivative for example,
leading to the formation of the desired coupling products
regioselectively at the C(2) carbon. As already under-
lined for complexes 2, both substitution of the η5 ring
and steric hindrance did not seem to affect the arylation
process (Table 2, entries 2, 3).
(η5-Cyclohexadienyl)Mn complexes such as 4, 5, and
8 are very useful in synthesizing new cationic (η6-arene)-
Mn(CO)3 complexes. For example, by reacting CPh3-
BF413 with complex 5c, we obtained the formation of the
cationic complex 9 in 93% yield by abstracting the exo
hydrogen at C(6) (Scheme 2). This is the key point of
our approach: the introduction of a new group (Ar or
Th) at the π-carbon system leaves the sp3 carbon
4-7). No steric hindrance effect was detected, and yields
ranged between 48 and 78%. From there it follows that
the withdrawing ability of the Mn(CO)3 entity allowed
the oxidative addition of Pd(0) into the C-Cl bond with
formation of a transient η5-bimetallic intermediate 6
(Figure 1).
An easy activation of the C-Cl bond toward zerova-
lent palladium complex insertion has been described11
in the case of cationic (η6-chloroarene)Mn(CO)3 deriva-
tives, but the corresponding (η6-arene)bimetallic adduct
7 was so stable that no further reaction was possible
(Figure 1).
(13) Woo, K.; Williard, P. G.; Sweigart, D. A.; Duffy, N. W.;
Robinson, B. H.; Simpson, J . J . Organomet. Chem. 1995, 487, 111.
(14) Lee, S. S.; Lee, T. Y.; Lee, J . E.; Lee, I. S.; Chung, Y. K.; Lah,
M. S. Organometallics 1996, 15, 3664. J ackson, J . D.; Villa, S. J .; Bacon,
D. S.; Pike, R. D.; Carpenter, G. B. Organometallics 1994, 13, 3972,
and references therein.
According to our results, η5-bimetallic intermediate
6 could react very smoothly with stannyl derivatives and
the X-ray structure of 5b15 allowed us to verify the
following points: (a) the reaction of stannyl derivatives
occurred on the carbon C(1), which bore the halogeno
group in the starting material; (b) the η5-cyclohexadienyl
structure was preserved, in good agreement with lit-
erature data.12 The five ring carbon atoms C(1), C(2),
C(3), C(4), and C(5) are almost coplanar, while the
remaining atom C(6) lies on the opposite side of this
plane from the Mn(CO)3 moiety. The plane makes a 40°
angle with that defined by C(1), C(6), and C(5) carbon
atoms.
(15) Typical arylation procedure: preparation of tricarbonyl(4-meth-
yl(1-thienyl)cyclohexadienyl)manganese complex 5b. Pd2(dba)3 (0.019
g, 0.02 mmol) and AsPh3 (0.21 g, 0.07 mmol) were added successively
to complex 2b (0.063 g, 0.2 mmol) in 10 mL of anhydrous degassed
DMF. After 15 min at room temperature, 2-tributylstannylthiophene
(0.071 g, 0.2 mmol) in 1 mL of DMF was added. The mixture was
stirred at room temperature for 20 h, poured into 100 mL of ice cold
water, and extracted twice with 50 mL of diethyl ether. The combined
organic phases were dried over magnesium sulfate, filtered, and
evaporated under reduced pressure. The residue was then purified by
flash chromatography on silica gel (pentane) to afford complex 5b (Rf
) 0.29). The pale yellow solid was finally recrystallized from diethyl
ether with petroleum ether in 48% yield. IR (CH2Cl2) ν(CO): 1917,
1998 cm-1 1H NMR (CDCl3, 200 MHz): δ 1.90 (s, 3H, CH3), 2.51 (d,
.
Unexpectedly, the use of phosphorus-based ligands
(such as P(OEt)3, PPh3, dppf, PtBu3) instead of AsPh3
gave no coupling products. We observed instead disap-
pearance of the starting material with decomposition
of the metallic entity.
J ) 12 Hz, 1H, H-6exo), 3.15 (d, J ) 6 Hz, 1H, H-5), 3.24 (dd, J ) 12,
6 Hz, 1H, H-6endo), 5.22 (dd, J ) 3, 6 Hz, 1H, H-2), 5.74 (d, J ) 6 Hz,
1H, H-3), 6.84 (d, J ) 4 Hz, 1H, H-10), 6.92 (m, 1H, H-9), 7.15 (d, J )
4 Hz, 1H, H-8). 13C NMR (CDCl3, 100 MHz): δ 21.9 (CH3), 29.3 (C-6),
50.8 (C-5), 77.9 (C-3), 94.1 (C-2), 97.8 (C-4), 106.2 (C-1), 122.3 (C-10),
124.8 (C-9), 127.7 (C-8), 133.8 (C-7), 223.2 (CO). UV/vis (CH2Cl2): λmax
(ꢀ) 232 nm (10800), 318 (6200). Anal. Calcd: C 53.51, H 3.53. Found:
C 53.59, H 3.75. Crystal data for 5b: C14H11O3SMn, M ) 314.24, crystal
dimensions 0.30 × 0.60 × 0.60 mm, monoclinic, space group P21/n, a
) 11.579(2) Å, b ) 9.819(2) Å, c ) 11.988(1) Å, R ) 94.95(1)°, V )
1357.9(4) Å3, Z ) 4, F ) 1.54 g cm-3, µ ) 1.08 mm-1, θ range 1-28°,
192 variables were refined for 2312 independent reflections with I >
3σ(I) to R ) 0.0441, Rw ) 0.0562, and GOF ) 0.79. Data were collected
The use of the above-mentioned catalytic conditions
allowed the reaction of the regioisomer complexes 3
(11) Carpentier, J . F.; Castanet, Y.; Brocard, J .; Mortreux, A.; Rose-
Munch, F.; Susanne, C.; Rose, E. J . Organomet. Chem. 1995, 493, C22.
(12) See for example: Balssa, F.; Gagliardini, V.; Lecorre-Susanne,
C.; Rose-Munch, F.; Rose, E.; Vaissermann, J . Bull. Soc. Chim. Fr.
1997, 134, 537, and references therein.
on
a CAD4 Enraf-Nonius diffractometer at 295 K with Mo KR
radiation, refinements based on F were carried out with CRYSTALS.

Communications
Organometallics, Vol. 20, No. 10, 2001 1903
unsubstituted and then allows an easy change of hap-
ticity (η5 into η6) by removing the exo hydride. This
avoids the use of oxidative processes with consequent
loss of the Mn moiety as usually reported.1b,2
ation14 of a Mn(CO)3 entity with the starting organic
product. Examination of the detailed mechanism of this
reaction as well as its generalization to other examples
is currently underway.
In conclusion, we have discovered the first Stille
coupling reactions involving (η5-halogenocyclohexadi-
enyl)Mn(CO)3 complexes giving rise to an overall “ipso”
substitution of the chloro group by an aryl group. This
process could represent an interesting alternative and
complementary method of selective preparation of sub-
stituted tricarbonyl(η6-arene) manganese complexes
when they cannot be synthesized using direct complex-
Su p p or tin g In for m a tion Ava ila ble: Text giving spectral
data for the new compounds and tables of crystal data, atomic
coordinates, and bond distances and angles for compound 5b.
This material is available free of charge via the Internet at
http://pubs.acs.org.
OM000831D