Synthesis and reactivity of (?5-Hydroxyalkylcyclohexadienyl) Mn(CO)3 complexes

Article abstract of DOI:10.1021/om100062m

(?⁵-1-Hydroxyalkylcyclohexadienyl)tricarbonylmanganese complexes 3a and 3b have been prepared, and their rearomatization delivered compounds 5 and 6, the first benzylic alcohol derivatives coordinated to the cationic Mn(CO)₃ tripod. The structure of 5 has been determined by X-ray crystallography. 1-Hydroxyalkyl 3a, 7, 8, 2-hydroxyalkyl 19, 20, and 3-hydroxyalkyl 25, 26 (?⁵-cyclohexadienyl)tricarbonylmanganese complexes have been synthesized and studied toward trifluoroacetylation of the hydroxy group when submitted to the action of NEt₃ and (CF ₃CO)₂O. Only the 2-hydroxyalkyl-substituted complexes eclipsed by a Mn?CO bond of the Mn(CO)₃ tripod gave the expected trifluoroacetate derivatives 21 and 22. For the 1-hydroxyalkyl-substituted complexes, elimination of the trifluoroacetoxy group took place followed by decoordination of the Mn(CO)₃ moiety and trifluoroacetylation, giving rise to trifluoromethyltrienones 10, 11, and 12, whose stuctures were established by X-ray analysis. For 3-hydroxyalkyl-substituted complexes, elimination of the trifluoroacetoxy group also occurred, yielding free arenes 27 and 28 by decoordination of the Mn(CO)₃ entity.

Full text of DOI:10.1021/om100062m

1778 Organometallics 2010, 29, 1778–1788
DOI: 10.1021/om100062m
Synthesis and Reactivity of (η5-Hydroxyalkylcyclohexadienyl)Mn(CO)3
Complexes
Derya Cetiner, Lucie Norel, Jean-Philippe Tranchier, Franc-oise Rose-Munch,* Eric Rose,*
and Patrick Herson
ꢀ
Institut Parisien de Chimie Moleculaire IPCM, CNRS UMR 7201, UPMC Universite Paris 6,
4 Place Jussieu, Case 181, and Centre de Resolution de Structure, Case 42, F-75005 Paris, France
ꢀ
ꢀ
Received January 25, 2010
(η5-1-Hydroxyalkylcyclohexadienyl)tricarbonylmanganese complexes 3a and 3b have been pre-
pared, and their rearomatization delivered compounds 5 and 6, the first benzylic alcohol derivatives
coordinated to the cationic Mn(CO)3 tripod. The structure of 5 has been determined by X-ray
crystallography. 1-Hydroxyalkyl 3a, 7, 8, 2-hydroxyalkyl 19, 20, and 3-hydroxyalkyl 25, 26 (η5-
cyclohexadienyl)tricarbonylmanganese complexes have been synthesized and studied toward trifluoro-
acetylation of the hydroxy group when submitted to the action of NEt3 and (CF3CO)2O. Only the 2-
hydroxyalkyl-substituted complexes eclipsed by a Mn-CO bond of the Mn(CO)3 tripod gave the
expected trifluoroacetate derivatives 21 and 22. For the 1-hydroxyalkyl-substituted complexes, elimina-
tion of the trifluoroacetoxy group took place followed by decoordination of the Mn(CO)3 moiety and
trifluoroacetylation, giving rise to trifluoromethyltrienones 10, 11, and 12, whose stuctures were
established by X-ray analysis. For 3-hydroxyalkyl-substituted complexes, elimination of the trifluoro-
acetoxy group also occurred, yielding free arenes 27 and 28 by decoordination of the Mn(CO)3 entity.
Introduction
to provide access to a wide variety of organic and organometallic
target molecules (Scheme 1).2 For example, lithiation/electro-
philic quench gives rise to substituted η5-complexes (Scheme 1,
step a, R = H).3 For bromo-substituted complexes, metal-
bromide exchange reaction allows the regioselective functiona-
lization of the η5-cyclohexadienyl ligand (step b, R = Br).4 Pd-
catalyzed cross-coupling reactions applied to chloro-substituted
complexes afford the substitution of the halogen (step c, R = Cl;
this correspond to an averall ipso5-substitution) and keto
derivatives when the reaction is performed under CO atmo-
sphere (step d, R = Cl).6 An alternative method giving access to
η5 keto derivatives complexes involves an organomanganese
transmetalation catalyzed by Fe(acac)3.7 (η5-X-substituted-
cyclohexadienyl)tricarbonylmanganese complexes, X being
Cationic (η6-arene)tricarbonylmanganese complexes repre-
sent an important class of organometallic compounds due to
the electrophilic character of the arene ring coordinated to the
Mn(CO)3 tripod.1 Thus nucleophiles react easily with these η6-
arene complexes to give stable neutral (η5-cyclohexadienyl)tri-
carbonylmanganese complexes. They are of strategic importance
*Corresponding authors. E-mail: francoise.rose@upmc.fr; eric.rose@
upmc.fr.
(1) (a) McDaniel, K. F. In Comprehensive Organometallic Chemistry
II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon Press: Oxford,
UK, 1995; Vol. 6, pp 93-107. (b) Rose-Munch, F.; Gagliardini, V.; Renard,
C.; Rose, E. Coord. Chem. Rev. 1998, 249. (c) Pike, R. D.; Sweigart, D. A.
Coord. Chem. Rev. 1999, 187, 183. (d) Pape, A. R.; Kaliappan, K. P.;
K€undig, E. P. Chem. Rev. 2000, 100, 2917. (e) Rose-Munch, F.; Rose, E. Eur.
J. Inorg. Chem. 2002, 1269. (f) K€undig, E. P. Topics in Organometallic
Chemistry; Springer: Berlin, 2004; Vol. 7. (g) Astruc, D. Organometallic
Complexes and Catalysis; Springer: Heidelberg, 2007; pp 243-249.
(2) (a) Pearson, A. J.; Lee, S. H.; Gouzoules, F. J. Chem. Soc., Perkin
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Pearson, A. J.; Shin, H. Tetrahedron 1992, 48, 7527. (e) Roell, B. C.; Mc
Daniel, K. F.; Vaughan, W. S.; Macy, T. S. Organometallics 1993, 12, 224. (f)
Djukic, J. P.; Rose-Munch, F.; Rose, E.; Dromzee, Y. J. Am. Chem. Soc.
1993, 115, 6434. (g) Pearson, A. J.; Gontcharov, A. V.; Zhu, P. Y. Tetra-
hedron 1997, 53, 3849. (h) Pearson, A. J.; Vickerman, R. J. Tetrahedron
Lett. 1998, 39, 5931. (i) Rose-Munch, F.; Rose, E. Curr. Org. Chem. 1999,
3, 445. (j) Sweigart, D. A., Reingold, J. A., Son, S. U., Crabtree, R. H.,
Mingos, D. M. P., Eds. Comprehensive Organometallic Chemistry III;
Elsevier: Oxford, UK, 2006; Vol. 5, pp 761-814.
(4) Eloi, A.; Rose-Munch, F.; Rose, E.; Lennartz, P. Organometallics
2009, 28, 5757.
(5) (a) Whiting, M. C. (Ethyl Corp.) U.S. Pat. 3 225 071 1966 (Chem.
Abstr. 1966, 64, 6694h). (b) Knipes, A. C.; McGuiness, J.; Watts, W. E. J.
Chem. Soc., Chem. Commun. 1979, 842. (c) Bunnett, J. F.; Hermann, H. J.
Org. Chem. 1971, 36, 4081. (d) Rose-Munch, F.; Rose, E.; Semra, A.;
Garcia-Oricain, J.; Knobler, C. J. Organomet. Chem. 1989, 363, 297. (e)
Rose-Munch, F.; Aniss, K.; Rose, E. J. Organomet. Chem. 1990, 385, C1. (f)
Rose-Munch, F.; Aniss, K.; Rose, E.; Vaisserman, J. J. Organomet. Chem.
1991, 415, 223.
(6) (a) Auffrant, A.; Prim, D.; Rose-Munch, F.; Rose, E.; Vaisser-
mann, J. Organometallics 2001, 20, 3214. (b) Auffrant, A.; Prim, D.; Rose-
Munch, F.; Rose, E.; Vaissermann, J. Organometallics 2003, 22, 1898. (c)
Prim, D.; Planas, J. G.; Auffrant, A.; Rose-Munch, F.; Rose, E.; Vaissermann,
J. J. Organomet. Chem. 2003, 688, 273. (d) Jacques, B.; Tranchier, J.-P.;
Rose-Munch, F.; Rose, E.; Stephenson, R.; Guyard-Duhayon, C. Organo-
metallics 2004, 23, 184. (e) Prim, D.; Andrioletti, B.; Rose-Munch, F.; Rose,
E.; Couty, F. Tetrahedron 2004, 60, 3325. (f) Schouteeten, S.; Tranchier, J.-
P.; Rose-Munch, F.; Rose, E.; Auffrant, A.; Stephenson, R. Organometallics
2004, 23, 4308.
(3) (a) Jacques, B.; Chavarot, M.; Rose-Munch, F.; Rose, E. Angew.
Chem., Int. Ed. 2006, 45, 3481. (b) Jacques, B.; Chanaewa, A.; Chavarot-
ꢀ
Kerlidou, M.; Rose-Munch, F.; Rose, E.; Gerard, H. Organometallics 2008,
27, 626. (c) Jacques, B.; Eloi, A.; Chavarot-Kerlidou, M.; Rose-Munch, F.;
Rose, E.; Gerard, H.; Herson, P. Organometallics 2008, 27, 2505. (d) Cetiner,
ꢀ
D.; Jacques, B.; Payet, E.; Chavarot-Kerlidou, M.; Rose-Munch, F.; Rose, E.;
Tranchier, J. P.; Herson, P. J. Chem. Soc., Dalton Trans. 2009, 27.
(7) Eloi, A.; Rose-Munch, F.; Rose, E.; Chavarot-Kerlidou, M.;
Gerard, H. Organometallics 2009, 28, 925.
r
pubs.acs.org/Organometallics
Published on Web 03/05/2010
2010 American Chemical Society

Article
Organometallics, Vol. 29, No. 7, 2010 1779
Scheme 1. Reactivity Features of (η5-Cyclohexadienyl)tricar-
bonylmanganese Complexes
We observed that (η5-cyclohexadienyl)tricarbonylmanga-
nese complexes substituted at the C1 position by a keto
group, obtained via a palladium-catalyzed carbonylative
coupling (step d), can undergo the addition of a hydride13
or a Grignard reagent to deliver the corresponding (η5-
cyclohexadienyl)tricarbonylmanganese complexes substi-
tuted by a hydroxyalkyl group.14 Alternatively a one-pot
access to such η5-alcohol derivatives was also developed by
lithiation of an η5-complex followed by electrophilic quench
(step a) using an aldehyde or a ketone.3a Thus, these two
methods of preparation of “benzylic” alcohols are efficient
and can be applied to synthesize a large variety of hydro-
xyalkyl η5-Mn complexes to address the question of their
reactivity according to the different positions of the hydro-
xyalkyl group toward the π η5-system. Here we report on the
synthesis of five (η5-cyclohexadienyl)tricarbonylmanganese
complexes substituted at the C1, C2, and C3 carbon atoms by
a hydroxyalkyl group and the study of their reactivity toward
trifluoroacetic anhydride in the presence of triethylamine as
well as the preparation and the structure of the first examples
of η6-benzylic alcohols coordinated to the cationic tricarbo-
nylmanganese tripod.
Results and Discussion
Hydroxyalkyl-substituted η5-complexes studied in this work
were prepared from keto derivative complexes using the two
different methodologies described vide infra, depending on the
position of the keto group on the π η5-system. For the C1-
substituted complexes, we chose the Pd cross-coupling method
to form a suitable keto group, starting from the easily avail-
able (η5-1-chloro-4-methoxycyclohexadienyl)Mn(CO)3.6a,b For
the other regioisomers, we performed lithiation/electrophilic
quench sequences3a starting either from the (η5-1-chloro-4-
methoxycyclohexadienyl)Mn(CO)3 complex for the C2 isomer
or from the (η5-2-methoxycyclohexadienyl)Mn(CO)3 for the
C3 isomer.
C1-Substituted Complexes: Preparation and Reactivity of
η5-(1-Hydroxyalkylcyclohexadienyl)Mn(CO)3 Derivatives.
(η5-Ketocyclohexadienyl) Mn(CO)3 complex 2a was ob-
tained by Stille reaction of (η5-1-chloro-4-methoxycyclo-
hexadienyl)Mn(CO)3 (1a) with ThSnBu3 (Th = 2-thienyl,
-C4H3S) under carbonylative conditions (Scheme 2).4b Ad-
dition of Grignard reagents such as PhMgBr and o-MeO-
C6H4MgBr in THF at 0 °C to the ketone 2a gave the alcohols
3a and 3b in 86% and 88% yield, respectively. For each
alcohol, two diastereoisomers could be formed due to the
planar chirality of the η5-complexes, and according to the
crude mixture NMR data, a 95% diastereoisomeric ratio
determined by 1H NMR analysis was observed, in contrast
with the addition of CH3MgBr, where no diastereoselectivity
was observed probably due to steric reasons.14 After careful
purification by silica gel chromatography, only one diaster-
eoisomer could be isolated in each case. No addition to an
internal position of the η5-cyclohexadienyl ring was detected,
unlike the deuteride addition to complex 2b, which occurred
not only at the ketone carbonyl group but also at the C2
carbon atom to form a 2-deuterated cyclohexadiene.13 No
reaction of Grignard reagent PhMgBr or o-MeO-C6H4MgBr
a good leaving group such as OMe, Cl, NR02, or SR00, treated
with a hydride and an acid eliminate HX via cine, tele-meta, and
tele-para nucleophilic substitutions (step e).8-11 For (η5-cyclo-
hexadienyl)tricarbonylmanganese complexes, rearomatization
takes place with CPh3BF4 if the exo R1 substituent is a hydrogen,
yielding the (η6-arene)tricarbonylmanganese complexes (step f).6
Finally very recently the first resolution of η6-arene-Mn com-
plexes was reported as well, which permits an easy access to
enantiopure (η5-cyclohexadienyl)- and (η6-arene)tricarbonyl-
manganese complexes.12 Indeed, we showed that addition of
D-(þ)-camphor enolate to a cationic substituted η6-arene-Mn
complex gave η5-Mn diastereoisomers, which can be easily
separated by silica gel chromatography (step g). Rearomatiza-
tion of these enantiopure η5-Mn complexes by elimination of the
chiral auxiliary gave enantiopure η6-Mn complexes (step h). This
new methodology opens the way to organic enantioselective
syntheses.11 Thus, starting with enantiopure anisole complexes,
for example (R0 = OMe), they lead to enantiopure 4-substi-
tuted-cyclohexenones, after the addition of hydride and then of a
stabilized nucleophile Nu- (step i).
(8) For cine and tele nucleophilic substitutions of Mn complexes, see:
(a) Balssa, F.; Gagliardini, V.; Rose-Munch, F.; Rose, E. Organome-
tallics 1996, 15, 4373. The first cine,9 tele-meta,10 and tel-para11 SNAr in
organometallic chemistry have been discovered in the η6-Cr complex series.
For ipso substitutions of Cr complexes see SNAr ipso.5d-f
(9) (a) Rose-Munch, F.; Rose, E.; Semra, A. Chem. Commun. 1986,
1551. (b) Rose-Munch, F.; Rose, E.; Semra, A.; Jeannin, Y.; Robert, F. J.
Organomet. Chem. 1988, 353, 53. (c) Rose-Munch, F.; Rose, E.; Semra, A.;
Bois, C. J. Organomet. Chem. 1989, 363, 103. (d) Djukic, J. P.; Rose-
Munch, F.; Rose, E. Chem. Commun. 1991, 22, 1634. (e) Rose-Munch, F.;
Bellot, O.; Mignon, L.; Semra, A.; Robert, F.; Jeannin, Y. J. Organomet.
Chem. 1991, 402, 1.
(10) (a) Boutonnet, J. C.; Rose-Munch, F.; Rose, E. Tetrahedron
Lett. 1985, 26, 3989. (b) Rose-Munch, F.; Rose, E.; Semra, A. Chem.
Commun. 1986, 1108. (c) Rose-Munch, F.; Rose, E.; Semra, A.; Garcia-
Oricain, J.; Knobler, C. J. Organomet. Chem. 1989, 363, 297.
(11) (a) Rose-Munch, F.; Rose, E. Chem. Commun. 1987, 942. (b)
Boutonnet, J. C.; Rose-Munch, F.; Rose, E.; Semra, A. Bull. Soc. Chim. Fr.
1987, 640. (c) Djukic, J. P.; Rose-Munch, F.; Rose, E. Organometallics 1995,
14, 2027.
(13) Eloi, A.; Rose-Munch, F.; Jonathan, D.; Tranchier, J.-P.; Rose,
E. Organometallics 2006, 25, 4554.
(14) Cetiner, D.; Tranchier, J. P.; Rose-Munch, F.; Rose, E.; Herson,
(12) Eloi, A.; Rose-Munch, F.; Rose, E. J. Am. Chem. Soc. 2009, 131,
14178.
P. Organometallics 2008, 27, 784.

1780 Organometallics, Vol. 29, No. 7, 2010
Cetiner et al.
Scheme 2. Preparation of (η6-Hydroxyalkylare-
ne)tricarbonylmanganese Complexes
Figure 1. ORTEP view of complex 5 with thermal ellipsoids at
1
˚
the 30% probability level. Selected bond lengths (A): Mn-C
2.194(7); Mn-C2 2.176(8); Mn-C3 2.190(10); Mn-C4 2.267(9);
Mn-C5 2.191(9); Mn-C6 2.175(8); C1-C2 1.424(11); C2-C3
1.416(12); C3-C4 1.400(14); C4-C5 1.394(14); C5-C6 1.392(13);
C6-C1 1.409(12); C4-O2 1.321(12); C1-C8 1.512(11); C8-O1
1.420(9).
was observed with keto complexes 2b and 2c, probably
because of the steric bulk of the substituent at the C6 sp3
carbon atom. Taking advantage of the rearomatization
procedure by exo-hydride abstraction15 already successfully
exploited in our group,6 we submitted complexes 3a and 3b
to the action of CPh3BF4 and isolated the cationic para-
disubstituted (η6-arene)Mn(CO)3 tertiary alcohols 5 and 6 in
nonoptimized 39% and 30% yield, respectively. Although
the yields were not completely satisfying, the syntheses of
complexes 5 and 6 represent an important step in the
chemistry of cationic η6-manganese complexes. Indeed,
benzylic alcohols do not coordinate the Mn(CO)3þ fragment
whatever the complexation procedure used,16 and to our
knowledge, these complexes are the first examples of benzylic
alcohol derivatives of η6-Mn complexes, whereas analogous
compounds of the isoelectronic neutral chromium complexes
are well precedented.17
Table 1. Crystallographic Data for 5, 8a, and 12
5
8a
12Z
formula
C
21H16BF4-
MnO5S
C
19H15Mn-
O5S2
C18H13F3-
O2S2
fw (g mol-1
)
522.15
10.583(6)
39.81(3)
10.614(4)
90
97.04(4)
90
4438(5)
8
monoclinic
P21/c
63.137
1.56
442.39
382.43
8.2373(5)
8.4549(5)
12.1930(8)
79.270(5)
83.503(6)
87.168(6)
828.63(9)
2
triclinic
P1
3.62
1.53
φ/ω
˚
a (A)
9.0856(7)
10.5404(10)
11.8873(8)
101.426(6)
103.627(7)
113.916(6)
954.53(16)
2
triclinic
P1
9.375
1.54
φ/ω
˚
b (A)
˚
c (A)
R (deg)
β (deg)
γ (deg)
3
˚
V (A )
Z
cryst syst
space group
abs μ (cm-1
density F (g cm-3
scan type
)
1
Selected H NMR data of the π-system protons of alco-
)
hols 3a and 3b are in good agreement with an η5-structure.
Indeed signals at 4.64 (H2), 5.61 (H3), 2.93 (H5) and at 4.50
(H2), 5.59 (H3), 3.01 (H5) ppm are respectively observed for
3a and 3b. The two H6 endo and exo hydrogens resonate at
2.17 (d) and 3.17 (dd) for complex 3a and at 2.06 (d) and 3.28
ppm (dd) for complex 3b. The two diastereotopic protons
ortho to the OMe group on the coordinated ring for com-
plexes 5 and 6 resonate as expected at low chemical shifts.9e,18
Complex 5 crystallized from acetone by a two-well diffu-
sion procedure (diethyl ether in the outer well), and the
ORTEP view is presented in Figure 1 as well as selected
bond lengths (Table 1). The Mn(CO)3 tripod adopts an
almost perfectly syn-eclipsed conformation with respect to
the methoxy group and an anti-eclipsed one to the sterically
2θ/ω
scan range (deg)
θ limits (deg)
hkl limits
2-77
2-30
2-30
12-13
-13,13;
0,50; 0,13
1-25
3-18
-12,12; -14,11; -11,11; -11,11;
-15,16
10 884
5518
-17,17
15 293
4809
no. data collected 10 046
no. unique data
no data used
9376
3866[I
2447[I
2441[I
> 2σ(I)]
> 3σ (I)]
> 3σ (I)]
Ra
Rw
0.0932
0.100
1.094
597
-0.74
0.98
0.0579
0.0630
1.127
231
-1.27
1.28
0.0002
0.047
0.050
1.115
227
-0.46
0.45
0.0001
P
b
GOF
no variables
ΔFmin (e A
ΔFmax (e A
(shift/esd)max
-3
˚
)
)
-3
˚
0.0079
P
P
P
a R =
Fo| - |Fc /| |Fo|. b Rw = [ w(|Fo| - |Fc|)2/ w|Fo|2]1/2
.
demanding C8 carbon atom.9e,19 Five Mn-C distances of the
6
˚
˚
η -system lie around 2.18 A, but a longer distance of 2.26 A is
observed for the Mn-C4 bond, leading to a small distortion
in the sense that the C carbon atom is displaced by 0.08 A
from the plane of the five other carbon atoms in a direction
opposite the Mn(CO)3 entity. This is in good agreement with
what is known also for (η6-arene)tricarbonylchromium com-
plexes where distorsions of the arene ligands are influenced
by the electronegativity, the inductive, and the resonance
effects of the arene substituents.20 A structural feature of
complex 5 is observed corresponding to a strong hydrogen
bonding between each hydroxy group of the alcohol function
4
˚
(15) Pauson, P. L.; Segal, J. A. J. Chem. Soc., Dalton Trans. 1975,
1677.
(16) Jackson, J. D.; Villa, S. J.; Bacon, D. S.; Pike, R. D.; Carpenter,
G. B. Organometallics 1994, 13, 3972.
(17) (a) Jaouen, G. Ann. N.Y. Acad. Sci. 1977, 295, 59. (b) Jaouen, G.
Pure Appl. Chem. 1986, 58, 597.
(18) Rose-Munch, F.; Rose, E.; Semra, A. J. Organomet. Chem. 1989,
377, C9.
(19) Boutonnet, J. C.; Rose-Munch, F.; Rose, E.; Jeannin, Y.;
-
and a fluorine atom of the BF4 anion. Two of the four F
(20) Djukic, J. P.; Rose-Munch, F.; Rose, E.; Vaissermann, J. Eur. J.
Inorg. Chem. 2000, 1295.
Robert, F. J. Organomet. Chem. 1985, 297, 185.

Article
Organometallics, Vol. 29, No. 7, 2010 1781
Scheme 3. Addition of Hydride to (η5-Cyclohexadienyl)tricar-
bonylmanganese Complex 2c
-
atoms of one BF4 participate in hydrogen bond formation.
Pertinent data documenting the hydrogen bonding are the
distances (O1) H1 F14 2.014(6) and O1 F14 2.798(10) A
˚
3 3 3
3 3 3
and the angle O1-H1-F14:161.99(5)°. A relevant example has
been reported concerning the structure of [(η6-hydroqui-
none)Mn(CO)3]2SiF6, where the hydrogen bonding links each
hydroxy substituent and a fluorine atom in the SiF62- anion21a
and in manganese21b and rhodium21c organometallic systems.
The reactivity of the tertiary alcohol 3a was investigated
toward trifluoroacetic anhydride in order to prepare the
corresponding trifluoroacetate 4 (Scheme 2). Unexpectedely,
complex 3a treated with NEt3 (2 equiv) and (CF3CO2)2O at
0 °C (2 equiv) in CH2Cl2 did not yield the expected complex 4,
but a very dark red solution, which afforded after silica gel
column chromatography the trienone10 in 34% yield, and the
starting material was recovered in 61% yield (Scheme 4).
Figure 2. ORTEP representation of complex 8a with thermal
ellipsoids at the 30% probability level. Selected bond lengths
1
(A): Mn-C 2.219(5); Mn-C2 2.192(5); Mn-C3 2.135(5);
˚
Mn-C4 2.136(4); Mn-C5 2.213(4); C1-C2 1.391(7); C2-C3
1.417(7), C3-C4 1.416(7); C4-C5 1.393(6); C5-C6 1.518(6),
C6-C1 1.527(6).
1
Scheme 4. Preparation of Trienones 10-12
Indeed, the H NMR spectrum of 10 no longer exhibits the
(η5-cyclohexadienyl)Mn(CO)3 fingerprint of 3a: 4.64 (H2, d
J = 6 Hz); 5.61 (H3, d, J = 6 Hz); 2.33 (H5, m); 2.17 (H6exo, d
J = 13 Hz); 3.17, H6endo, dd J = 13 and 6 Hz). Instead, two
olefinic protons appear as two doublets at 6.08 and 6.70 ppm
with a J value of 10 Hz, in good agreement with an R-
methylene cyclohexadiene structure. The two H6 allylic pro-
tons resonate as a singlet at 3.94 ppm, and the 19F NMR
spectrum shows a signal at -75.5 ppm, compatible with the
presence of a trifluoroacetyl group, whichcould be introduced
by a Fridel-Craft reaction. Thus, the structure of this com-
pound agrees with a trienone skeleton.
same experimental conditions as those used for complex 3. This
gave rise to the formation of trifluoromethyltrienone 11 or 12 as
a cis/trans 10:8 or 5:1 mixture of two isomers in 76% and 80%
We then extended our study to the secondary alcohols 713
and 8. The latter compound was prepared under the same
experimental conditions as for complex 7. Reduction of
ketone 2c by NaBH4 gave complex 8, formed as two diaster-
eoisomers, 8a and 8b (60:40 ratio), in an overall 81% yield
along with the cyclohexadienone 9 in 13% yield (Scheme 3).
The conjugated ketone is formed by an internal 1,4-addition
of a hydride to the C2 carbon of the π-system, as already
shown in the case of the η5-complex bearing a phenyl group
at the sp3 carbon atom.13
1
yield, respectively (Scheme 4). Selected H NMR spectra of
trienones 11 (ZþE) and12 (ZþE) show again a cyclohexadiene
structure with two olefinic protons at 6.23 and 7.00 ppm for
11Z, 6.43 and 7.49 ppm for 11E, 6.33 and 7.05 ppm for 12Z,
and 6.44 and 7.56 ppm for 12E as doublets with a J value of 10
Hz. In both cases, the conjugation and thus the electron
delocalization are better in the E isomer than in the Z one.
Indeed, the largest difference of chemical shifts Δδ=δH2 - δH3
was found to be 1.06 ppm for 11E and 0.77 ppm for 11Z and
1.12 ppm for 12E and 0.82 ppm for 12Z.
The major diastereoisomer 8a gave yellow crystals suitable
for X-ray analysis (Table 1). The ORTEP view, presented
Figure 2, shows that the (η5-cyclohexadienyl)Mn(CO)3 moi-
eties exhibit the classical five coplanar carbon geometry
(C1C2C3C4C5) with carbon C6 lying out of this plane. The
dihedral angle between the C1C2C3C4C5 and C1C6C5 planes
The major isomer 12Z easily offered red-purple crystals
suitable for X-ray analysis, by recrystallization from a con-
centrated solution in CH2Cl2 of a mixture of 12Z and 12E.
The ORTEP view is presented in Figure 3. Compound 12Z
presents a conjugated system of six double bonds, C1-C7,
C2-C3, C4-C5, C13-O1, C8-C9, C10-C11, almost in the
7
2
˚
reaches 39°. The 1.413(6) A value for the C -O bond length
is in good agreement with a single carbon-oxygen bond.13
The dihedral angle of thienyl ring C8C9C10C11S and C8C7O2
is 50°, the sulfur atom pointing toward the metal atom and in
the direction opposite the sp3 carbon atom.
7
˚
same plane, with a 0.31 A deviation of the C carbon atom
from the mean plane. The C1-C7 double bond adopts a cis
conformation, and the interplanar angle between the
C1C2C3C4C5 and the C1C6C5 planes (24°) is smaller than in
8a (39°), vide supra, in good agreement with the transforma-
tion of the η5-cyclohexadienyl structure of the starting com-
plex into a cyclohexadiene one. The cis-geometry of the
thiophene unit and of the cyclohexadiene residue shown by
the X-ray structure permitted us to unambigously assign the
chemical shifts of the olefin protons of cyclohexadienes 12Z
and 12E.
The mixture of diastereoisomers of complexes 7 and 8 was
submitted to the action of NEt3 and (CF3CO)2O under the
(21) (a) Sun, S. S.; Carpenter, G. B.; Sweigart, D. A. J. Organomet.
Chem. 1996, 512, 257. (b) Oh, M.; Carpenter, G. B.; Sweigart, D. A. Acc.
Chem. Res. 2004, 37, 1. (c) Son, S. U.; Reingold, J. A.; Carpenter, G. B.;
Czech, P. T.; Sweigart, D. A. Organometallics 2006, 25, 5276.

1782 Organometallics, Vol. 29, No. 7, 2010
Cetiner et al.
Scheme 5. Suggested Mechanism for the Preparation of Com-
plexes 10-12
Figure 3. ORTEP representation of 12Z with thermal ellipsoids
1
2
˚
at the 30% probability level. Selected bond lengths (A): C -C
1.442(4), C2-C3 1.343(4) C3-C4 1.448(4), C4-C5 1.367(4),
C5-C6 1.521(3), C1-C6 1.526(3), C1-C7 1.350(4).
The formation of the trienones 10, 11, and 12 could be
explained if we assume first the formation of the correspond-
ing trifluoroacetates 13, whose benzylic carbon should be
anti-eclipsed with respect to a Mn-CO bond, then elimina-
tion of the trifluoroacetoxy group (Scheme 5). Formation of
the corresponding carbocation 14, stabilized or not by the
Mn(CO)3 entity, could be represented by the mesomeric
form η4/η2: 15. After decoordination of the [Mn(CO)3L3]þ
unit, trifluoroacetylation could afford the trienone 10, 11, or
12 from the free trienol ethers 16. This reaction could occur
with the trienol ether still coordinated to the Mn(CO)3 unit,
but this is unlikely for such an electrophilic complex. We
previously observed the elimination of a β-hydrogen from a
cationic secondary benzylic intermediate, giving rise to a
styrene-like structure.14 Here, the tertiary cationic benzylic
intermediate has no β-hydrogen to be eliminated and evolves
differently.
Scheme 6. Mn-Mediated Dearomatization Reaction
complexes that are reactivated by the replacement of a CO
ligand with NOþ, in order to obtain cationic η5-Mn com-
plexes, which can add a less reactive nucleophile depending
on the nature of the substituents on the aromatic ring of the
starting complex.24 Again an oxidative decomplexation is
necessary to provide the dearomatized compound. The
results reported here show a new series of more sophisticated
dearomatized compounds that are obtained without prior
reactivation of the η5-complexes and without double addi-
tion of nucleophiles.
Transition metal based dearomatization reactions have been
intensively developed starting from arenes coordinated either in
a hexahapto fashion or in a dihapto one. The first methodology
involves electrophilic η6-arenes coordinated to Cr(CO)3,25 Mn-
(CO)3,2a-e,26 RuCp,27 and FeCp28 (Cp = cyclopentadienyl).
Here we focus on dearomatization of arene-metal giving cy-
clohexadienes derivatives. For Mn complexes, path a, they can
react with two nucleophiles Nu- and Nu0- to yield disubstituted
cyclohexadiene intermediates (Scheme 7, paths b and c), which
The transformation of the η5-Mn complexes into trifluoro-
methylated trienones is interesting since the introduction of a
CF3 group into an organic molecule is an important chal-
lenge22 because of the stereoelectronic properties of the CF3
moiety and the bioavailability brought by this group.23
The overall process starting from the cationic η6-p-chloro-
anisole Mn complex 17 represents a new Mn-mediated
dearomatization reaction (Scheme 6). Indeed, up to now,
Mn-mediated dearomatization reactions required in all cases
the double addition of two nucleophiles to cationic η6-Mn
complexes. It is reported that the most direct route to
dearomatized products, such as cis-1,2-disubstituted cyclo-
hexadienes, involves for the first addition the use of nucleo-
philes such as MeLi or hydrides and, for the second one, a
reactive nucleophile such as a stabilized carbanion R to a
nitrile or an ester followed by decomplexation by stirring in
the presence of oxygen.1d,2e An alternative method for
dearomatization reactions implicates η5-neutral manganese
(24) (a) Chung, Y. K.; Sweigart, D. A.; Connelly, N. G.; Sheridan, J.
B. J. Am. Chem. Soc. 1985, 107, 2388. (b) Pike, R. D.; Sweigart, D. A.
Synlett 1990, 565. (c) Pike, R. D.; Ryan, W. J.; Lennhoff, N. S.; Van Epp, J.;
Sweigart, D. A. J. Am. Chem. Soc. 1990, 112, 4798. (d) Lee, T.-Y.; Kang,
Y. K.; Chung, Y. K.; Pike, R. D.; Sweigart, D. A. Inorg. Chim. Acta 1993,
214, 125.
(25) (a) Semmelhack, M. F. In Comprehensive Organometallic Chem-
istry II; Wilkinson, G., Abel, E. W., Stone, F. G. A., Eds.; Pergamon Press:
Oxford, UK, 1995; Vol. 2.4, p 517. (b) Uemura, M. In Organic Reactions;
Hoboken, NJ, 2006; p 67. (c) McGlinchey, M. J.; Ortin, Y.; Seward, C. M. In
Comprehensive Organometallic Chemistry III; Theopold, K. H., Ed.;
Pergamon Press: Oxford, UK, 2007; Vol. 5, Chapter 4.
(26) (a) Miles, W. H.; Smiley, H. R.; Brinkman, J. J. Chem. Soc.,
Chem. Commun. 1989, 659. (b) Pearson, A. J.; Zhu, P. Y. J. Am. Chem. Soc.
1993, 115, 10376. (c) Pearson, A. J.; Bruhn, P. R. J. Org. Chem. 1991, 56,
7092. (d) Pearson, A. J.; Milletti, M. C.; Zhu, P. Y. J. Chem. Soc., Chem.
Commun. 1995, 1309. (e) Pearson, A. J.; Vickerman, R. J. Tetrahedron Lett.
1998, 39, 5931. (f) Dudones, J. D.; Pearson, A. J. Tetrahedron Lett. 2000,
41, 8037.
(27) Heo, J.-N. Org. Lett. 2002, 2, 2987.
(28) (a) Pearson, A. J.; Park, J. G. J. Org. Chem. 1992, 57, 1744. (b)
Astruc, D. Tetrahedron 1983, 39, 4027.
(22) (a) Schlosser, M. Angew. Chem., Int. Ed. 2006, 118, 5558. (b)
Kieltsch, I.; Eisenberg, P.; Togni, A. Angew. Chem., Int. Ed. 2007, 119, 768.
(c) O'Hogan, D. Chem. Soc. Rev. 2008, 37, 308.
(23) (a) Smart, B. E. In Organofluorine Chemistry: Principles and
Commercial Applications; Banks, R. E., Smart, B. E., Tatlow, J. C., Eds.;
Plenum Press: New York, 1994; Chapter 3, p 57. (b) Kirsch, P. Modern
Fluoroorganic Chemisrty: Synthesis Reactivity, Applications; Wiley-
VCH: Weinheim, 2004.

Article
Organometallics, Vol. 29, No. 7, 2010 1783
Scheme 7. Dearomatization Reactions
Scheme 8. Preparation and Reactivity of η5-(2-
Hydroxyalkylcyclohexadienyl)Mn(CO)3 Complexes
form η4-quinone-methides, which are the precursors of
various reactions.31
C2-Substituted Complexes: Preparation and Reactivity of
η5-(2-Hydroxyalkylcyclohexadienyl) Mn(CO)3 Derivatives.
We then undertook the study of the reactivity of the C2-
substituted hydroxyalkyl complexes 19 and 20, which were
both prepared using a lithiation/electrophilic quench sequ-
ence.3a-c Thus reaction of complex 1b with nBuLi followed
by benzaldehyde trapping gave the secondary alcohol 193b
(two diastereoisomers in a 75:25 ratio, Scheme 8). Reaction
of 1b with nBuli followed by DMF quench gave the aldehyde
18,3c which was reduced with NaBH4 into the primary
alcohol 20 in 91% yield. After NEt3 and (CF3CO)2O treat-
ment, each of these alcohols gave rise to the formation of new
η5-complexes 21 (only one diastereoisomer) and 22, corre-
sponding to the protection of the hydroxy group by a
trifluoroacetyl residue, in 61% and 96% yield, respectively
(Scheme 8). Thus, there is no further evolution, and the
reaction stops at the step of the formation of the trifluoro-
acetoxy derivatives, which substitutes a benzylic carbon that
should be eclipsed by a Mn-CO bond.27 Encouraged by
these results, we then progressed by studying alcohols whose
hydroxylmethyl group substitutes the C3 carbon of the
cyclohexadienyl unit.
can liberate free cyclohexadienes.2e If Nu0 = H, the neutral η5-
Mn complexes yield anionic η4-cyclohexadiene-manganese
intermediates (path c), which afford complexes with agostic
Mn-C-H bonds if treated with an acid, path d.29 For Cr
complexes, path e, they can react with a nucleophile Nu- and
then with an electrophile Eþ to afford cyclohexadiene inter-
mediates substituted by Nu and COE and then the free
cyclohexadiene (Scheme 7, paths f and g, E = tBu, Me).1d,f
If Eþ is a proton, an anionic cyclohexadiene intermediate is
recovered, path h, giving a cyclohexadiene by oxidation,
path i.25a The second methodology involving the dearoma-
tization of an arene into a cyclohexadiene corresponds to
η2-arenes coordinated to one double bond of an arene with
[Os(NH3)5]2þ or TpRe(CO)L fragments, path j.30 These Os
and Re complexes are electron rich and react with electro-
philes Eþ to afford cyclohexadienyl cations, path k, which
can be further elaborated for example with a nucleophile
Nu-, path l, or reaoromatized. Thus this complementary
methodology easily transforms an arene into a 3,6-disubsti-
tuted 1,4-cyclohexadiene (Scheme 7).
C3-Substituted Complexes: Preparation and Reactivity of
η5-(3-Hydroxyalkylcyclohexadienyl) Mn(CO)3 Derivatives.
Lithiation of the (η5-2-methoxycyclohexadienyl)tricarbonyl-
manganese complex 23 withnBuLi in the presence of TMEDA
occurred at the C3 carbon3b and, after trapping with 2-
formylthiophene, lead to the secondary alcohol 25, formed
as two diastereoisomers in a 45:55 ratio and in 67% overall
yield (Scheme 9). The reaction with NEt3 and (CF3CO)2O
unexpectedely afforded the biphenyl compound 27 in 97%
yield. In order to generalize this reaction and to obtain more
insight into its mechanism, we performed the same sequence
starting withthe (η5-2-methoxycyclohexadienyl)-Mn complex
24 obtained by addition of a hydride to the cationic anisole
tricarbonylmanganese complex. Treatment of 24 with nBuLi
and 2-formylthiophene yielded the secondary alcohol26atthe
C3 position of the π-system in a >95:5 ratio and in 79% yield.
Complex 26 reacted with NEt3 and (CF3CO)2O to deliver in
30% yield the arene 28, substituted by the trifluoroacetyl
groupatoneof the ortho positionswithrespect tothe methoxy
group (Scheme 9).
Finally, it should also be pointed out that another dear-
omatization reaction is well known in the particular case of
phenol derivatives giving cyclohexadiene derivatives. In-
deed, treatment of phenol with [CpIrL3]2þ complexes gives
η5-oxo-cyclohexadienyl derivatives, which can react with
NuLi to deliver η4-cyclohexadienone. The cationic η5-oxo-
t
cyclohexadienyl Ir or Rh complexes react with BuOK to
(29) (a) Lamanna, W.; Brookhart, M. J. Am. Chem. Soc. 1981, 103,
989. (b) Brookhart, M.; Lamanna, W.; Pinhas, A. R. Organometallics 1983,
2, 638. (c) Brookhart, M.; Lukacs, A. J. Am. Chem. Soc. 1984, 106, 4161.
(30) (a) Kopach, M. E.; Harman, W. D. J. Am. Chem. Soc. 1994, 116,
6581. (b) Smith, P. L.; Chordia, M. D.; Harman, W. D. Tetrahedron 2001, 57,
8203. (c) Valahovic, M. T.; Keane, J. M.; Harman, W. D. In Modern Arene
Chemistry; Astruc, D., Ed.; Wiley, VCH, 2002. (d) Harman, W. D. The
Dearomatization of Arenes by Dihapto-Coordination. In Topics in Organo-
metallic Chemistry; K€undig, E. P., Ed.; Springer: Berlin, 2004; Vol. 7, p 95.
(31) (a) Vigalok, A.; Milstein, D. J. Am. Chem. Soc. 1997, 119, 7873.
(b) Amouri, H.; Le Bras, J. Acc. Chem. Res. 2002, 35, 501. (c) Van der Boom,
M. E.; Milstein, D. Chem. Rev. 2003, 103, 1759.

1784 Organometallics, Vol. 29, No. 7, 2010
Cetiner et al.
Scheme 10. Possible Mechanism of Formation of 28
Scheme 9. Preparation and Reactivity of η5-(3-
Hydroxyalkylcyclohexadienyl)Mn(CO)3 Complexes
A plausible mechanism explaining these results, very
similar to the one presented for the C1-substituted complexes
in Scheme 5, could involve the trifluoroacetylation of 25 or
26 into the trifluoroacetate 29 or 30, which could eliminate
the CF3CO2 group, giving an unstable cationic Mn inter-
mediate 31 or 32, whose mesomeric forms 33 or 34 could be
envisaged. The decoordination of the cationic Mn(CO)3
entity would liberate the free triene 35 or 36. Two paths
would be possible depending on the nature of the R sub-
stituent. For R = Ph, the isomerization of the triene 35 via a
1,5-hydrogen atom migration could occur to form the con-
jugated biphenyl product 27. For R = H, the intermediate 36
could be acylated via a Friedel-Craft trifluoroacetylation
before its rearomatization into compound 28 (Scheme 10).
Thus (η5-1-, 2-, and 3- hydroxyalkylcyclohexadienyl)tri-
carbonylmanganese complexes submitted to the action of
NEt3 and (CF3CO)2O give in all cases the corresponding
trifluoroacetates. But only the C2-trifluoroacetoxyalkyl-sub-
stituted complexes are stable enough to be isolated. We do
not know why the cleavage of the C-O bond of the
-RHC-OCOCF3 group is inhibited in this case and if the
conformation of the Mn(CO)3 tripod eclipsing the C2 carbon
is involved.32 However, for the C1- and C3-trifluoroacetoxy-
alkyl-substituted complexes, which are anti-eclipsed with
respect to the tripod, elimination of the trifluoroacetoxy
group takes place followed by decoordination of the Mn-
(CO)3 moiety. Thus, the driving force of these reactions
seems to be the formation of the conjugated exocyclic olefin
at the C5 position of the cyclohexadiene 16 as well as of the
exocyclic olefin at the C3 position conjugated to two double
bonds, C1dC2 and C4dC5, of the cyclohexadienes 33 and 34.
We did not succeed in trapping any of the postulated cationic
intermediates 14 or 15, 31 or 33, or 32 or 3433 and recovered
instead the rearrangement products, namely, the trienones
10-12 as well as the arenes 27 and 28.
Conclusion
This work describes the synthesis of the two first benzylic
alcohol derivatives coordinated to a cationic Mn(CO)3þ moi-
ety, 5 and 6. Then, 1-hydroxyalkyl 3a, 7, 8, 2-hydroxyalkyl 19,
20, and 3-hydroxyalkyl 25, 26 (η5-cyclohexadienyl)tricarbonyl-
manganese complexes substituted at the C1, C2, and C3 posi-
tions have been studied toward trifluoroacetylation of the
hydroxy group when submitted to the action of NEt3 and
(CF3CO)2O. The most striking feature of these results is the
different reactivities of the three types of regioisomers. Indeed,
only the hydroxyalkyl group eclipsed by a Mn-CO bond that
substitutes the complexes 19 and 20 at the C2 position gives the
expected trifluoroacetate derivatives 21 and 22, stable enough
to be isolated and fully characterized. For C1-hydroxyalkyl-
substituted complexes, elimination of the trifluoroacetoxy
group takes place followed by decoordination of the Mn(CO)3
moiety and trifluoroacetylation, giving rise to unprecedented
trifluoromethyltrienones. The overall process of these reactions
giving the ketones 10-12 and starting from the cationic η6-p-
chloroanisole Mn complex represents a new Mn-mediated
dearomatization reaction. For C3-hydroxyalkyl-substituted
complexes, elimination of the trifluoroacetoxy group also
occurs followed by decoordination of the Mn(CO)3 entity,
and 1,5-hydrogen shift yields free arenes 27 and 28.
(32) Work is in progress to determine if the conformation of the
Mn(CO)3 tripod with respect to the “benzylic” carbons is involved in the
reactivity of the 2-hydroxyalkyl regioisomers. The role of the conforma-
tion of the metal-carbonyl tripod has been described in particular cases
to explain the regioselectivity of the carbanion addition in the
η6-(arene)tricarbonylchromium complex series and the benzylic reacti-
vity of arene tricarbonylchromium complexes: (a) Solladie-Cavallo, A.;
ꢀ
Suffert, J. Org. Magn. Reson. 1980, 14, 426. (b) Solladie-Cavallo, A.;
Wipff, G. Tetrahedron Lett. 1980, 3047. (c) Albright, T. A.; Carpenter, B. K.
Inorg. Chem. 1980, 19, 3092. (d) Mutterties, E. L.; Bleeke, J. R.; Wucherer,
E. J.; Albright, T. A. Chem. Rev. 1982, 82, 499. (e) Semmelhack, M. F.;
Garcia, J. L.; Cortes, D.; Farina, R.; Hong, R.; Carpenter, B. K. Organome-
tallics 1983, 2, 463. (f) Ohlsson, B.; Ullenius, C. J. Organomet. Chem. 1988,
350, 35. (g) Volk, T.; Bernicke, D.; Bats, J. W.; Schmalz, H.-G. Eur. J. Inorg.
Chem. 1998, 1883. (h) Merlic, C. A.; Walsh, J. C.; Tantillo, D. J.; Houk, K. N.
J. Am. Chem. Soc. 1999, 121, 3596. (i) Pfletschinger, A.; Koch, W.;
Schmalz, H.-G. New J. Chem. 2001, 25, 446.
(33) For the reactivity at the benzylic position of arenetricarbonyl-
chromium complexes, see for example: (a) Jaouen, G. Ann. N.Y. Acad.
Sci. 1977, 295, 59. (b) Jaouen, G. Pure Appl. Chem. 1986, 58, 597. (c)
Davies, S. G.; Donohoe, T. J. Synlett 1993, 5, 323. (d) Davies, S. G.;
McCarthy, T. D. In Comprehensive Organometallic Chemistry II; Abel, E.
W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon Press: Oxford, UK, 1995;
Vol. 12, Chapter 9.3, p 1039. (e) Pfletschinger, A.; Dargel, T. K.; Bats, J. W.;
Schmalz, H.-G.; Koch, W. Chem.;Eur. J. 1999, 5, 537. (f) Gibson, S. E.;
Ibrahim, H. J. Chem. Soc., Chem. Commun. 2002, 2465.
Experimental Section
General Procedures. All rections were routinely performed
under a dry nitrogen atmosphere with standard Schlenk tech-
niques. THF was dried over sodium benzophenone ketyl and
distilled. N,N,N0,N0-Tetramethylethylenediamine (TMEDA)
˚
was distilled over KOH and stored under nitrogen over 4 A
molecular sieves. CH2Cl2 and DMF were distilled over CaH2.
NMR spectra were recorded on a Bruker ARX 200 MHz or
1
Avance 400 MHz spectrometer. H and 13C signals of NMR
solvents were used as internal standards respectively at 7.26 and
77.36 ppm in CDCl3 and at 2.09 and 30.60 ppm in acetone-d6.
The Mn(CO)3 carbonyl signal is known to be difficult to
observe, especially when only low quantities of complex are
available. Infrared spectra were measured on a Bruker Tensor

Article
Organometallics, Vol. 29, No. 7, 2010 1785
27 spectrometer. Mass spectra were performed for ES-MS by
ꢀ
HAr), 7.25-7.33 (m, 6H, HAr). 13C NMR (100 MHz, CDCl3): δ
28.1 (C6), 36.2 (C5), 54.5 (OMe, 64.9 (C2), 77.9 (C7), 79.6 (C1),
93.8 (C3), 125.8 (CHAr), 125.9 (CHAr), 126.6 (CHAr), 127.2
(CHAr), 128.1 (CHAr), 142.7 (CAr), 143.7 (CAr), 148.8 (CAr).
Anal. Calcd for C21H17O5MnS: C, 57.80; H, 3.93. Found: C,
57.89; H, 3.83. MS (ESI, positive mode): m/z 435.0093 (M - Hþ,
calcd for C21H16O5MnS, 435.0099). IR (neat): ν (cm-1) 1914
(Mn(CO)3), 2009 (Mn(CO)3), 3502 (OH).
Complex 3b. To a solution of 2a (0.304 g, 0.85 mmol) in THF
(15 mL) was added o-OMeC6H5MgCl (1.6 mL, 1.6 mmol, 1 N, 2
equiv) at 0 °C. The yellow solution was stirred at 0 °C for 20 min.
Then water (30 mL) was added, and the aqueous phase was
extracted with Et2O. The organic phase was washed with water
(50 mL) and a saturated solution of NaCl (50 mL) and dried over
MgSO4. After concentration in vacuo, the crude mixture was
purified by flash chromatography on silica gel to afford 3b
(0.350 g, 0.75 mmol, 88%) as a yellow solid. 1H NMR (200
MHz, CDCl3): δ 1.58 (s, 1H, OH), 2.06 (d, 2J = 13.3 Hz, 1H,
H6exo), 3.01 (dd, 3J = 5.8 Hz, 4J = 2.6 Hz, 1H, H5), 3.28 (ddd,
2J = 13.3 Hz, 3J = 5.8 Hz, 4J = 1.2 Hz, 1H, H6endo), 3.44 (s, 3H,
H7), 4.05 (s, 3H, H19), 4.50 (dd, 3J = 5.4 Hz, 4J = 1.2 Hz, 1H,
H2), 5.59 (dd, 3J = 5.4 Hz, 4J = 2.6 Hz, 1H, H3), 6.75-6.30 (m,
7H, HAr). 13C NMR (100 MHz, CDCl3): δ 28.0 (C6), 38.1 (C5),
54.4 (C7), 55.1 (C19), 64.2 (C3), 77.4 (C8), 82.1 (C1), 93.5 (C2),
112.0 (CHAr), 120.5 (CHAr), 125.9 (CHAr), 126.0 (CHAr), 126.4
(CHAr), 129.5(CHAr), 130.3 (CHAr), 128.7 (C13), 143.7 (C4),
147.8 (C9), 156.4 (C18). IR (neat): ν (cm-1) 1998 (Mn(CO)3),
1905 (Mn(CO)3), 3500 (OH).
the Groupe de Spectrometrie de Masse (IPCM, UMR 7201
ꢀ
UPMC) and for EI-MS by the Service de Spectrometrie de
Masse de l’ENS (Chemistry Dpt, Paris). Complexes 1a,6b 1b,6b
2,6b 7,13 18,3c 19,3b 23,34 and 263b were synthesized according to
procedures previously described in the literature.
Preparation of η5-(1-Hydroxyalkylcyclohexadienyl)Mn(CO)3
Complexes. Complex 1c. To a solution of ether (4 mL) contain-
ing Mg (1.215 g, 50 mmol, 1 equiv) and one crystal of iodine
under N2 was added 2-bromothiophene (50 mmol, 1 equiv). To
the boiling reaction mixture was added Et2O (16 mL), and the
solution heated under reflux for 2 h. In bicol-containing para-
chloro anisole-Mn(CO)3BF4 (0.552 g, 1.50 mmol) in THF (15
mL) under N2 at 0 °C was added 2-thienylmagnesium bromide
(1.4 mL of the preceding solution, 3.1 mml, 2.1 equiv). The
resulting red solution was stirred for 40 min at 0 °C. After
addition of 2 M HCl (40 mL) and ether (20 mL), the organic
phase was extracted with water (50 mL), with saturated K2CO3
solution (50 mL) and saturated NaCl solution (50 mL), and
dried over MgSO4. The solvents were removed under reduced
pressure, and the recovered yellow oil was purified on a silica gel
chromatography column, giving quantitatively complex 1c. 1H
NMR (200 MHz, CDCl3): δ 7.11 (dd, J = 5 and 1 Hz, 1H, H10),
6.87 dd, J = 5 and 3 Hz, 1H, H9), 6.68 (d, J = 3 Hz, 1H, H8),
5.59 (dd, J = 6 and 3 Hz, 1H, H3, 5.17 (dd, J = 6 and 2 Hz, 1H,
H2), 4.42 (ddd, J = 6, 1, and 0.5 Hz, 1H, H6), 3.61 (dd, J = 7 and
3 Hz, 1H, H5), 3.52 (s, 3H, OMe). 13C NMR (100 MHz, CDCl3):
δ 148.4 (Cquat), 141.5 (Cquat), 126.7 (C9), 124.5 (C10), 123.4 (C8),
91.8 (C2), 65.0 (C3), 54.9 (OMe), 47.3 (C6), 45.1 (C5). MS (IC,
NH3): m/z 364 (M), 335 (M - CO), 308 (M - 2CO), 280 (M -
3CO). IR (neat): ν (cm-1) 2015, 1922.
Complex 5. To a solution of complex 3a (0.222 g, 0.5 mmol) in
CH2Cl2 (5 mL) was added CPh3BF4 (0.168 g, 0.5 mmol, 1 equiv)
in 5 mL of CH2Cl2. The mixture was stirred at room temperature
for 30 min. The η6-cationic(arene)Mn(CO)3 5 was precipitated
by adding 30 mL of dry Et2O, filtered, washed with Et2O, and
dried in vacuo. A yellow solid was obtained (0.042 g, 0.08 mmol,
Complex 2c. In a two-neck flask containing AsPh3 (0.092 g,
0.33 mmol, 0.3 equiv) and Pd2(dba)3 (0.092 g, 0.1 mmol, 0.1
equiv) was added complex 1c (0.360 g, 0.99 mmol) in THF (15
mL). CO was bubbled into this brown solution for 10 min, and
ThSnBu3 (1.29 mmol, 1.3 equiv) was added with a microsyringe.
The solution was heated under reflux for 1 h under a CO
atmosphere under the hood. Sometimes, it is necessary to add
AsPh3/Pd to complete the reaction. Filtration of the solution on
Celite and extraction of the organic phase with water (2 ꢀ 50
mL) gave a green oil after evaporation of the solution under
reduced pressure. Complex 2c was recovered pure after silica gel
1
39%). H NMR (200 MHz, (CD3)2CO): δ 4.21 (s, 3H, OMe),
6.36 (d, 3J = 8.2 Hz, 2H, H3 and H5), 6.91-7.17 (m, 5H, H2, H6,
OH and HAr), 7.44-7.57 (m, 6H, HAr). 13C NMR (100 MHz,
(CD3)2CO): δ 58.9 (OMe), 77.4 (C1), 80.6 (C3 or C5), 82.0 (C5 or
C3), 104.4 (C2,C6), 117.2 (C8), 117.5 (CHAr), 127.8 (CHAr), 127.9
(CHAr), 129.0 (CHAr), 129.2 (CHAr), 129.6 (CHAr), 144.9(CAr),
150.2 (CAr), 125.4 (CAr). Anal. Calcd for C21H16MnO5SBF4: C,
48.30; H, 3.09. Found: C, 48.19; H, 3.01 MS (ESI, positive
mode): m/z 435.0093 (M - BF4þ, calcd for C21H16O5MnS:
435.0099). IR (neat): ν (cm-1) 2002 (Mn(CO)3), 2076 (Mn-
(CO)3), 3592 (OH).
chromatography in 79%0 yield. 1H NMR (200 MHz,0CDCl3): δ
0
7.60 (m, 2H, H8 and H9 ), 7.10 (m, 2H, H10 and H9 ), 6.84 dd,
J = 5 and 3 Hz 1H, H9), 6.60 (d, J = 3 Hz, 1H, H8), 6.33 (dd, J =
6 and 1 Hz, 1H, H2, 5.97 (dd, J = 6 and 2 Hz, 1H, H3), 4.99 (d,
J = 6 Hz, 1H, H6), 3.84 (dd, J = 6 and 2 Hz, 1H, H5), 3.52 (s,
3H, OMe). 13C NMR (100 MHz, CDCl3): δ 186.7 (C11), 150.0
(Cquat), 143.0 (C9), 140.7 (Cquat), 130.9 (CTh), 129.6 (CTh), 126.5
(CTh), 125.7 (C9), 123.1 (CTh), 121.8 (C8), 96.1 (C2), 71.0 (C3),
61.7 (Cquat), 54.1 (OMe), 44.3 (C5), 35.4 (C6). MS (FAB): m/z
441 (M þ 1), 385 (M - 2CO þ 1), 356 (M - 2CO), 280 (M -
3CO). IR (neat): ν (cm-1) 2017, 1930, 1602.
Complex 6. To a solution of complex 4 (0.150 g, 0.32 mmol) in
CH2Cl2 (5 mL) was added CPh3BF4 (0.105 g, 0.32 mmol, 1
equiv) in 5 mL of CH2Cl2. The mixture was stirred at room
temperature for 30 min. The η6-cationic(arene)Mn(CO)3 6 was
precipitated by adding 30 mL of dry Et2O, filtered, washed with
Et2O, and dried in vacuo. A yellow solid was obtained (0.069 g,
1
0.12 mmol, 30%). H NMR (200 MHz, (CD3)2CO): δ 3.76 (s,
3H, H19), 4.20 (s, 3H, OMe), 6.29 (dd, 4J = 2.7 Hz, 3J = 7.6 Hz,
1H, H3 or H5), 6.40 (dd, 4J = 2.7 Hz, 3J = 7.6 Hz, 1H, H3 or H5),
6.74 (s, 1H, OH), 6.82-7.67 (m, 9H, H2, H6, HAr). 13C NMR
(100 MHz, (CD3)2CO): δ 56.0 (C19), 58.9 (C7), 77.2 (C1), 79.1
(C5), 83.1 (C3), 104.7 (C2), 105.5 (C6), 116.7 (C8), 113.5 (CHAr),
121.6 (CHAr), 127.4 (CHAr), 127.5 (CHAr), 128.2 (CHAr), 128.7
(CHAr), 131.7(CHAr), 132.7 (C13), 148.9 (C4), 151.2 (C9), 157.3
(C18). Anal. Calcd for C22H18O6MnSBF4: C, 47.85; H, 3.29.
Found: C, 47.96; H, 3.34. MS (ESI, positive mode): m/z
465.0235 (M - BF4þ, calcd for C22H18O6MnS, 465.0205). IR
(neat): ν (cm-1) 2008 (Mn(CO)3), 2066 (Mn(CO)3), 3108 (OH).
Complex 8. To a solution of 2c (0.110 g, 0.25 mmol) in THF
(15 mL) was added NaBH4 (0.019 g, 0.50 mmol, 2 equiv) at 0 °C.
The yellow solution was stirred at 0 °C for 20 min. Then water
(30 mL) was added, and the aqueous phase was extracted with
Et2O. The organic phase was washed with water (50 mL) and a
saturated solution of NaCl (50 mL) and dried over MgSO4.
After concentration in vacuo, the crude mixture was purified by
Complex 3a. To a solution of 2a (0.976 g, 2.7 mmol) in THF
(15 mL) was added PhMgCl (2.7 mL, 5.4 mmol, 2 N, 2 equiv) at
0 °C. The yellow solution was stirred at 0 °C for 20 min. Then
water (30 mL) was added, and the aqueous phase was extracted
with Et2O. The organic phase was washed with water (50 mL)
and a saturated solution of NaCl (50 mL) and dried over
MgSO4. After concentration in vacuo, the crude mixture was
purified by flash chromatography on silica gel to afford 3a as a
1
yellow solid (1.011 g, 2.3 mmol, 86%). H NMR (200 MHz,
CDCl3): δ 2.17 (d, 2J = 12.9 Hz, 1H, H6exo), 2.93 (m, 2H, H5 and
2
3
4
OH), 3.17 (dd, J = 12.9 Hz, J = 6.5 Hz, J = 2.0 Hz, 1H,
H6endo), 3.46 (s, 3H, OMe), 4.64 (d, 3J = 6.0 Hz, 1H, H2), 5.61
(dd, 3J = 6.0 Hz, 4J = 2.0 Hz, 1H, H3), 6.84 (dd, 3J = 3.6 Hz,
4J = 1.2 Hz, 1H, HAr), 6.97 (dd, 3J = 3.6 Hz, 3J = 5.1 Hz, 1H,
(34) Chung, Y. K.; Williard, P. G.; Sweigart, D. A. Organometallics
1982, 1, 1053.

1786 Organometallics, Vol. 29, No. 7, 2010
Cetiner et al.
flash chromatography on silica gel to afford two diastereoi-
somers of 8 in a 40:60 ratio (0.089 g, 0.20 mmol, 81%) as a yellow
powder and 9 (0.010 g, 0.03 mmol, 13%).
silica gel to afford the two diastereoisomers of 11 as a red solid
(0.072 g, 0.19 mmol, 76%).
Diastereoisomer 11a. 1H NMR (200 MHz, CDCl3): δ 3.86 (s,
3H, OMe), 5.71 (s, 1H, H6), 6.27 (d, 3J = 9.3 Hz, 1H, H3), 7.00
1
Diastereoisomer 8a (49%). H NMR (200 MHz, CDCl3): δ
2.21 (d, 3J = 3.3 Hz, 1H, OH), 3.41 (dd, 3J = 6.3 Hz, 4J = 2.5
Hz, 1H, H5), 3.47 (s, 3H, OMe), 4.31 (d, 3J = 6.3 Hz, 1H, H6),
5.30 (d, 3J = 6.3 Hz, 1H, H2), 5.36 (d, 3J = 3.3 Hz, 1H, H11),
5.70 (dd, 3J = 6.3 Hz, 4J = 2.5 Hz, 1H, H3), 6.59 (d, 3J = 3.0 Hz,
1H, HAr), 6.78 (dd, 3J = 5.3 Hz, 4J = 3.0 Hz, 1H, HAr), 6.94 (m,
2H, HAr), 7.03 (d, 3J = 5.3 Hz, 1H, HAr), 7.22 (dd, 3J = 4.5 Hz,
4J = 1.9 Hz, 1H, HAr). 13C NMR (100 MHz, CDCl3): δ 38.7
(C6), 43.5 (C5), 53.6 (OMe), 64.8 (C3), 71.0 (C11), 89.9 (C2), 122.1
(CHAr), 123.6 (CHAr), 123.7 (CHAr), 125.5 (CHAr), 141.0 (CAr),
145.1 (CAr), 150.6 (CAr). SM (IC, NH3): m/z 459 (M þ 17, 28%),
415 (M - CO þ 1, 17%), 358 (M - 3CO, 38%), 327 (M - 3CO -
OMe, 100%). IR (neat): ν (cm-1) 1909 (Mn(CO)3), 2008
(Mn(CO)3).
(d, J = 9.3 Hz, 1H, H2), 7.00-7.40 (m, 9H, HAr). 13C NMR
3
(100 MHz, CDCl3: δ 39.8 (C6), 55.5 (OMe), 110.5 (Cq), 114.3
(C3), 126.6 (CHAr), 127.3 (CHAr), 128.0 (CHAr), 129.1 (CHAr),
130.3 (CHAr), 130.4 (CHAr and C7), 131.3 (CAr), 134.6 (CHAr),
138.2 (CAr), 141.2 (CAr), 143.3 (CAr), 164.3 (CAr). 19F NMR (376
MHz, CDCl3): δ -74.7 (CF3). Anal. Calcd for C20H15O2SF3: C,
63.82; H, 4.02. Found: C, 63.91; H, 4.09. MS (ESI, positive
mode): m/z 399.0637 (M þ Naþ, calcd for C20H15O2F3NaS,
399.0643). SM (IC, NH3): m/z 396 (M þ 18, 40%), 377 (M þ 1,
25%), 267. IR (neat): ν (cm-1) 1260, 1597, 1661, 2924.
Diastereoisomer 11b. 1H NMR (200 MHz, CDCl3): δ 3.96 (s,
3H, OMe), 4.86 (s, 1H, H6), 6.43 (d, 3J = 10.0 Hz, 1H, H3), 6.93
(s, 1H, H7), 6.90-7.50 (m, 8H, HAr), 7.49 (d, 3J = 10.0 Hz, 1H,
H2). 13CNMR (100 MHz, CDCl3): δ 47.6 (C6), 57.2 (OMe),
112.1 (CAr), 118.7 (C3), 126.8 (CHAr), 127.3 (CHAr), 127.7
(CHAr), 128.0 (CHAr), 128.8 (CHAr), 128.9 (CHAr), 130.7 (C7),
133.8 (CAr), 136.6 (C2), 138.2 (CAr), 138.7 (CAr), 143.1 (CAr),
164.2 (CAr). 19F NMR (376 MHz, CDCl3): δ -74.1 (CF3). MS
(ESI, positive mode): m/z 399.0637 (M þ Naþ, calcd for
C20H15O2F3NaS, 399.0643). IR (neat): ν (cm-1) 1124, 1741,
1810, 2927.
1
Diastereoisomer 8b (32%). H NMR (200 MHz, CDCl3): δ
2.19 (d, 3J = 3.5 Hz, 1H, OH), 3.45 (dd, 3J = 6.0 Hz, 4J = 2.5
Hz, 1H, H5), 3.49 (s, 3H, OMe), 4.46 (d, 3J = 6.0 Hz, 1H, H6),
4.97 (d, 3J = 6.0 Hz, 1H, H2), 5.40 (d, 3J = 3.5 Hz, 1H, H11),
5.67 (dd, 3J = 6.0 Hz, 4J = 2.5 Hz, 1H, H3), 6.45 (d, 3J = 3.0 Hz,
1H, HAr), 6.73 (dd, 3J = 5.3 Hz, 3J = 3.0 Hz, 1H, HAr), 6.88 (m,
2H, HAr), 6.97 (d, 3J = 5.3 Hz, 1H, HAr), 7.19 (dd, 3J = 4.5 Hz,
4J = 1.9 Hz, 1H, HAr). 13C NMR (100 MHz, CDCl3): δ 38.3
(C6), 42.5 (C5), 53.6 (OMe), 64.5 (C3), 69.4 (C11), 78.4 (CAr), 89.2
(C2), 122.0 (CHAr), 122.8 (CHAr), 124.2 (CHAr), 124.5 (CHAr),
125.3 (CHAr), 140.8 (CAr), 144.8 (CAr), 150.3 (CAr). SM (IC,
NH3): m/z 459 (M þ 17, 28%), 415 (M - CO þ 1, 17%), 358 (M
- 3CO, 38%), 327 (M - 3CO - OMe, 100%). IR (neat): ν
(cm-1) 1909 (Mn(CO)3), 2008 (Mn(CO)3).
Compound 12. To a solution of complex 8 (0.296 g, 0.67 mmol)
in CH2Cl2 (10 mL) was added Et3N (0.242 mL, 1.74 mmol, 2.6
equiv) and (CF3CO)2O (0.242 mL, 1.74 mmol, 2.6 equiv) at 0 °C.
The mixture turned yellow to red and was stirred for 1 h at room
temperature. Then water (30 mL) was added and the aqueous
phase was extracted with CH2Cl2. The organic phase was
washed with water (50 mL) and a saturated solution of NaCl
(50 mL) and dried over MgSO4. After concentration in vacuo,
the crude mixture was purified by flash chromatography on
silica gel to afford the two diastereoisomers of 12 as a red solid
(0.207 g, 0.54 mmol, 80%).
Compound 9 (13%). 1H NMR (200 MHz, CDCl3): δ 2.64 (dd,
2J = 17 Hz, 4J = 2 Hz, 1H, H5exo), 3.02 (ddd, 2J = 17 Hz, 3J =
8.2 Hz, 4J = 2.0 Hz, 1H, H5endo), 3.7 (s, 3H, OMe), 4.64 (d, 3J =
8.2 Hz, 1H, H6), 5.25 (dd, 3J = 7.1 Hz, 4J = 2.0 Hz, 1H, H3),
6.20-7.10 (m, 4H, HAr), 7.29 (d, 3J = 7.1 Hz, 1H, H2), 7.56 (m,
2H, HAr). 13C NMR (100 MHz, CDCl3): δ 32.0 (C6), 34.7 (C5),
54.7 (OMe), 92.1 (C3), 122.2 (CHAr), 123.0 (CHAr), 125.3
(CHAr), 126.2 (CHAr), 130.6 (CHAr), 130.7 (CHAr), 137.9 (C2),
184.0 (CdO). Anal. Calcd for C16H14O2S2: C, 63.55; H, 4.67.
Found: C, 63.48; H, 4.54. SM (IC, NH3): m/z 237 (M - Th þ 18,
90%), 192 (M - COTh þ 1, 7%), 179 (M - COTh - MeO þ 18,
30%).
Diastereoisomer 12a. 1H NMR (200 MHz, CDCl3): δ 3.92 (s,
3H, OMe), 5.97 (s, 1H, H6), 6.33 (d, 3J = 9.7 Hz, 1H, H3), 6.86 (t,
3J = 4.0 Hz, 1H, HAr), 6.98 (d, 3J = 4.0 Hz, 1H, HAr), 7.05 (d,
3J = 9.7 Hz, 1H, H2), 7.11 (m, 3H, H7 and HAr), 7.26 (d, 3J = 4.0
3
Hz, 1H, HAr), 7.48 (d, J = 4.0 Hz, 1H, HAr). 13C NMR (100
MHz, CDCl3): δ 38.0 (C6), 57.0 (OMe), 111.7 (CAr), 115.4 (C3),
1
117.6 (q, JCF = 286 Hz, CF3), 124.3 (CHAr), 125.3 (CHAr),
126.6 (CHAr), 128.2 (CHAr), 130.1 (CHAr), 132.0 (C7 and CHAr),
134.2 (CAr), 138.7 (CAr), 144.0 (C2), 145.3 (CAr), 165.0 (CAr),
177.6 (q, 2JCF = 37 Hz, CdO). 19F NMR (376 MHz, CDCl3): δ
-74.7 (CF3). Anal. Calcd for C18H13S2O2F3: C, 56.53; H, 3.43.
Found: C, 56.64; H, 3.55. MS (ESI, positive mode): m/z
383.0384 (M þ Hþ, calcd for C18H14O2F3S2, 383.0387). SM
(IC, NH3): m/z 400 (M þ 18, 100%), 383 (M þ 1, 40%). IR
(neat): ν (cm-1) 1259, 1608, 2360, 2962.
Compound 10. To a solution of complex 3a (0.107 g, 0.24
mmol) in CH2Cl2 (10 mL) were added Et3N (0.088 mL, 0.63
mmol, 2.6 equiv) and (CF3CO)2O (0.095 mL, 0.063 mmol, 2.6
equiv) at 0 °C. The mixture turned yellow to red and was stirred
for 1 h at room temperature. Then water (30 mL) was added and
the aqueous phase was extracted with CH2Cl2. The organic
phase was washed with water (50 mL) and a saturated solution
of NaCl (50 mL) and dried over MgSO4. After concentration in
vacuo, the crude mixture was purified by flash chromatography
on silica gel to afford 10 as a red solid (0.007 g, 0.019 mmol,
34%). 1H NMR (200 MHz, CDCl3): δ 1.25 (s, 2H, H6), 3.85 (s,
3H, OMe), 6.83 (d, 3J = 8.6 Hz, 1H, H3), 7.12 (d, 3J = 8.6 Hz,
1H, H2), 7.20 (m, 4H, HAr), 7.23 (m, 4H, HAr). 13C NMR
(CDCl3, 100 MHz): δ 30.0 (C6), 55.6 (OMe), 114.0 (C3), 126.5
(CHAr), 126.9 (CHAr), 126.9 (CHAr), 128.7 (CHAr), 129.1 (C2),
130.1 (CHAr), 136.4 (CAr), 144.4 (CHAr), 148.8 (CAr), 158.6
(CAr). 19F NMR (CDCl3, 376 MHz): δ -75.5 (CF3). Anal. Calcd
for C20H15O2SF3: C, 63.82; H, 4.02. Found: C, 63.59; H, 3.88.
Compound 11. To a solution of complex 7 (0.109 g, 0.25 mmol)
in CH2Cl2 (10 mL) was added Et3N (0.090 mL, 0.65 mmol, 2.6
equiv) and (CF3CO)2O (0.090 mL, 0.65 mmol, 2.6 equiv) at 0 °C.
The mixture turned yellow to red and was stirred for 1 h at room
temperature. Then water (30 mL) was added, and the aqueous
phase was extracted with CH2Cl2. The organic phase was
washed with water (50 mL) and a saturated solution of NaCl
(50 mL) and dried over MgSO4. After concentration in vacuo,
the crude mixture was purified by flash chromatography on
Diastereoisomer 12b. 1H NMR (200 MHz, CDCl3): δ 3.97 (s,
3H, OMe), 5.18 (s, 1H, H6), 6.44 (d, 3J = 10.1 Hz, 1H, H3), 6.90
(m, 1H, HAr), 6.91 (s, 1H, H7), 7.02 (s, 1H, HAr), 7.10 (m, 3H,
HAr), 7.11 (d, 3J = 3.5 Hz, 1H, HAr), 7.17 (d, 3J = 3.5 Hz, 1H,
HAr), 7.44 (d, 3J = 4.5 Hz, 1H, HAr), 7.56 (d, 3J = 10.1 Hz, 1H,
H2). 13C NMR (100 MHz, CDCl3): δ 41.5 (C6), 56.8 (OMe),
1
111.8 (CAr), 115.6 (C3), 117.6 (q, JCF = 290 Hz, CF3), 125.7
(CHAr), 127.3 (CHAr), 128.6 (CHAr), 129.3 (CHAr), 131.6 (CHAr
or C7), 131.7 (CHAr or C7), 135.1 (CAr), 138.5 (CAr), 142.5 (CAr),
2
144.6 (C2), 164.8 (CAr), 177.9 (q, JCF = 37 Hz, CdO). 19F
NMR (376 MHz, CDCl3): δ -74.1 (CF3). SM (IC, NH3): m/z
400 (M þ 18, 100%), 383 (M þ 1, 40%). IR (neat): ν (cm-1
)
1260, 1609, 1634, 2360, 2960.
Preparation of η5-(2-Hydroxyalkylcyclohexadienyl)Mn(CO)3
Complexes. Complex 20. NaBH4 (0.041 g, 1.08 mmol, 2.5
equiv) was slowly added to a solution of complex 18 (0.168 g,
0.43 mmol) in MeOH (10 mL) at 0 °C. The mixture was stirred for
30 min. Then the reaction was quenched by addition of 1 mL of a
concentrated HCl solution diluted with H2O. After extraction of

Article
Organometallics, Vol. 29, No. 7, 2010 1787
the reaction mixture with Et2O, the combined organic layers were
washed with H2O (50 mL) and a saturated solution of NaCl (50
mL) and dried over MgSO4. After concentration in vacuo, 20
addition of H2O. After extraction of the reaction mixture with
Et2O, the combined organic layers were washed with H2O and a
saturated aqueous NaCl solution and dried over MgSO4. After
concentration in vacuo, the crude mixture was purified by flash
chromatography on silica gel to afford two diastereoisomers in a
ratio of 45:55 of 25 (0.180 g, 0.40 mmol, 67%) as a yellow oil.
1
(0.152 g, 0.39 mmol, 91%) was obtained as a yellow solid. H
NMR (200 MHz, CDCl3): δ 2.27 (s, 1H, OH), 3.50 (s, 3H, OMe),
3.62 (dd, 3J = 6.5 Hz, 4J = 2.8 Hz, 1H, H5), 4.29-4.34 (m, 2H,
H6 and H11a), 4.58 (d, 2J = 13.8 Hz, 1H, H11b), 5.86 (d, 4J = 2.8
Hz, 1H, H3), 6.97-6.01 (m, 2H, HAr), 7.22-7.26 (m, 3H, HAr).
13C NMR (100 MHz, CDCl3): δ 46.4 (C5), 53.8 (C6), 55.1 (OMe),
63.2 (C11), 64.6 (C3), 78.3 (C1), 106.7 (C2), 126.3 (CHAr), 127.9
(CHAr), 128.9 (CHAr), 140.9 (CAr), 144.0 (CAr), 222.0
(Mn(CO)3). Anal. Calcd for C17H14O5ClMn: C, 52.53; H, 3.63.
Found: C, 52.64; H, 3.71. MS (ESI, positive mode): m/z 410.9802
(M þ Naþ, calcd for C17H14O5ClMnNa, 410.9808). IR (neat): ν
(cm-1) 1925 (Mn(CO)3), 2015 (Mn(CO)3).
1
Diastereoisomer 25a. H NMR (200 MHz, CDCl3): δ 2.55 (d,
3J = 3.3 Hz, 1H, OH), 3.36-3.38 (m, 2H, H1 and H5), 3.39 (s,
3H, OMe), 3.38 (t, 3J = 5.9 Hz, 1H, H6), 5.43 (d, 3J = 7.4 Hz,
1H, H4), 6.55 (d, 3J = 3.3 Hz, 1H, H11), 6.74 (m, 2H, HAr), 6.98
3
3
(dd, J = 3.5 Hz, J = 5.0 Hz, 1H, HAr), 7.09-7.12 (m, 4H,
HAr), 7.31 (dd, 3J = 1.2 Hz, 3J = 5.0 Hz, 1H, HAr). 13C NMR
(100 MHz, CDCl3): δ 41.8 (C1 or C5), 42.8 (C6), 54.9 (OMe), 57.1
(C1 or C5), 66.1 (C11), 90.1 (C4), 93.5 (C3), 124.3 (CHAr), 125.4
(CHAr), 125.8 (CHAr), 126.9 (CHAr), 127.1 (CHAr), 128.6
(CHAr), 141.3 (CAr), 147.3 (CAr), 149.2 (CAr), 222.7 (Mn-
(CO)3). MS (ESI, positive mode): m/z 459.0069 (M þ Naþ,
calcd for C21H17O5MnNaS, 459.0075). IR (neat): ν (cm-1) 1920
(Mn(CO)3), 2010 (Mn(CO)3), 2955 (OH). Diastereoisomer 25b.
1H NMR (200 MHz, CDCl3): δ 3.27 (t, 3J = 3.4 Hz, 1H, H5),
3.42-3.47 (m, 4H, H1 and OMe), 3.52 (d, 3J = 6.2 Hz, 1H, OH),
3.89 (t, 3J = 5.9 Hz, 1H, H6), 5.99 (d, 3J = 7.4 Hz, 1H, H4), 6.39
(d, 3J = 6.2 Hz, 1H, H11), 6.94 (dd, 3J = 1.8 Hz, 3J = 7.9 Hz,
2H, HAr), 7.01 (m, 1H, HAr), 7.12 (m, 1H, HAr), 7.16-7.32 (m,
4H, HAr). 13C NMR (100 MHz, CDCl3): δ42.7 (C5 and C6),
55.01 (OMe), 56.4 (C1), 69.7 (C11), 92.8 (C3), 93.3 (C4), 125.06
(CHAr), 125.4 (CHAr), 125.8 (CHAr), 127.0 (CHAr), 127.2
(CHAr), 128.8 (CHAr), 124.6 (CAr), 145.8 (CAr), 147.3 (CAr),
222.2 (Mn(CO)3). MS (ESI, positive mode): m/z 459.0069 (M þ
Compound 21. To a solution of complex 19 (0.166 g, 0.35
mmol) in CH2Cl2 (10 mL) were added Et3N (0.129 mL, 0.93
mmol, 2.6 equiv) and (CF3CO)2O (0.129 mL, 0.93 mmol, 2.6
equiv) at 0 °C. The mixture turned yellow to red and was stirred
for 1 h at room temperature. Then water (30 mL) was added and
the aqueous phase was extracted with CH2Cl2. The organic
phase was washed with water (50 mL) and a saturated solution
of NaCl (50 mL) and dried over MgSO4. After concentration in
vacuo, the crude mixture was purified by flash chromatography
on silica gel to afford 21 (only one diastereoisomer) as a yellow
solid (0.120 g, 0.21 mmol, 61%). 1H NMR (400 MHz, CDCl3): δ
3.51 (s, 3H, OMe), 3.69 (dd, 3J = 6.7 Hz, 4J = 2.6 Hz, 1H, H5),
4.27 (d, 3J = 6.7 Hz, 1H, H6), 5.06 (d, 4J = 2.6 Hz, 1H, H3), 6.51
(d, 3J = 7.4 Hz, 2H, HAr), 6.64 (s, 1H, H11), 6.96 (t, 3J = 7.6 Hz,
Naþ, calcd for C21H17O5MnNaS, 459.0075). IR (neat): ν (cm-1
)
3
2H, HAr), 7.04 (d, J = 7.3 Hz, 1H, HAr), 7.29-7.37 (m, 3H,
3
Ar), 7.52 (d, J = 7.3 Hz, 2H, HAr). 13C NMR (100 MHz,
1920 (Mn(CO)3), 2010 (Mn(CO)3), 2955 (OH).
H
CDCl3): δ 45.5 (C5), 53.1 (C6), 55.2 (OMe), 62.8 (C3), 75.4 (C1),
Compound 26. A solution of complex 24 (0.350 g, 1.4 mmol)
and freshly distilled TMEDA (0.340 mL, 2.3 mmol, 1.6 equiv) in 10
mL of THF was cooled to -78 °C. A solution of nBuLi (1.6 M in
hexanes, 1.4 mL, 2.3 mmol, 1.6 equiv) was slowly added. The
mixture was stirred for 1 h at -78 °C before the addition of
ThCHO (0.270 mL, 2.9 mmol, 2 equiv). It was stirred for another
hour at -78 °C before being warmed to room temperature and
quenched by addition of H2O. After extraction of the reaction
mixture with Et2O, the combined organic layers were washed with
H2O and a saturated aqueous NaCl solution and dried over
MgSO4. After concentration in vacuo, the crude mixture was
purified by flash chromatography on silica gel to afford 26 (two
diastereoisomers, dr = 95:5, 0.202 g, 0.56 mmol, 79%) as a yellow
76.8 (C11), 106.0 (C2), 114.7 (q, JCF = 284 Hz, CF3), 125.7
1
(CHAr), 127.5 (CHAr), 128.1 (CHAr), 128.3 (CHAr), 129.2
(CHAr), 130.2 (CHAr), 135.4 (CAr), 140.8 (CAr), 143.3 (CAr),
155.8 (q, 2JCF = 45 Hz, CdO). 19F NMR (376 MHz, CDCl3): δ
-74.9 (CF3). MS (ESI, positive mode): m/z 561.0119 (M þ Hþ,
calcd for C25H18O6ClF3Mn: 561.0124). IR (neat): ν (cm-1) 1793
(CdO), 1927 (Mn(CO)3), 2025 (Mn(CO)3).
Compound 22. To a solution of complex 20 (0.150 g, 0.38
mmol) in CH2Cl2 (10 mL) were added Et3N (0.140 mL, 1.0
mmol, 2.6 equiv) and (CF3CO)2O (0.140 mL, 1.0 mmol, 2.6
equiv) at 0 °C. The mixture turned yellow to red and was stirred
for 1 h at room temperature. Then water (30 mL) was added and
the aqueous phase was extracted with CH2Cl2. The organic
phase was washed with water (50 mL) and a saturated solution
of NaCl (50 mL) and dried over MgSO4. After concentration in
vacuo, the crude mixture was purified by flash chromatography
on silica gel to afford 22 as a yellow solid (0.177 g, 0.36 mmol,
96%). 1H NMR (200 MHz, CDCl3): δ 3.50 (s, 3H, OMe), 3.74
(dd, 3J = 6.7 Hz, 4J = 2.8 Hz, 1H, H5), 4.39 (d, 3J = 6.6 Hz, 1H,
H6), 5.08 (d, 2J = 12.5 Hz, 1H, H11a), 5.25 (d, 2J = 12.5 Hz, 1H,
H11b), 5.78 (d, 4J = 2.8 Hz, 1H, H3), 6.99 (m, 2H, HAr), 7.28 (m,
3H, HAr). 13C NMR (100 MHz, CDCl3): δ 46.3 (C5), 46.7 (C6),
52.9 (C12), 66.0 (C3), 67.3 (C11), 98.8 (C2), 114.6 (q, 1JCF = 283
Hz, CF3), 125.7 (CHAr), 127.9 (CHAr), 128.8 (CHAr), 140.5
(CAr), 143.5 (CAr), 157.0 (q, 2JCF = 43 Hz, CdO), 220.5
(Mn(CO)3). 19F NMR (376 MHz, CDCl3): δ -74.8 (CF3). Anal.
Calcd for C19H13MnF3O6Cl: C, 47.08; H, 2.70. Found: C, 47.20;
H, 2.83. IR (neat): ν (cm-1) 1790 (CdO), 1932 (Mn(CO)3), 2022
(Mn(CO)3).
1
2
oil. H NMR (400 MHz, CDCl3): δ 2.17 (d, J = 11.2 Hz, 1H,
6exo), 2.72 (m, 1H, H1 and H5), 2.89 (t, 3J = 4.9 Hz, 1H, H6endo),
H
3.42 (s, 3H, OMe), 3.52 (d, 3J = 5.5 Hz, 1H, OH), 4.84 (d, 3J = 6.2
Hz, 1H, H4), 6.52 (d, 3J = 5.5 Hz, 1H, H7), 7.04 (t, 3J = 3.6 Hz,
1H, HAr), 7.22 (d, 3J = 3.4 Hz, 1H, HAr), 7.31 (d, 3J = 4.3 Hz, 1H,
HAr). 13C NMR (100 MHz, CDCl3): δ 27.2 (C6), 34.9 (C1), 49.4
(C5), 54.9 (OMe), 69.8 (C7), 93.4 (C2), 94.9 (C4), 125.1 (CHAr),
125.5 (CHAr), 127.1 (CHAr), 142.5 (CAr), 145.8 (CAr). IR (neat): ν
(cm-1) 1915 (Mn(CO)3), 2006 (Mn(CO)3).
Compound 27. To a solution of complex 25 (0.180 g, 0.41
mmol) in CH2Cl2 (10 mL) was added Et3N (0.149 mL, 1.07
mmol, 2.6 equiv) and (CF3CO)2O (0.149 mL, 1.07 mmol, 2.6
equiv) at 0 °C. The mixture turned yellow to red and was stirred
for 1 h at room temperature. Then water (30 mL) was added and
the aqueous phase was extracted with CH2Cl2. The organic
phase was washed with water (50 mL) and a saturated solution
of NaCl (50 mL) and dried over MgSO4. After concentration in
vacuo, the crude mixture was purified by flash chromatography
on silica gel to afford 27 as a yellow solid (0.112 g, 0.40 mmol,
97%). 1H NMR (400 MHz, CDCl3): δ 3.89 (s, 3H, OMe), 4.17 (s,
2H, H11), 6.83 (s, 1H, HAr), 6.90 (1H, HAr), 7.08 (m, 3H, HAr),
7.20 (t, 3J = 7 Hz, 1H, HAr), 7.33 (d, 3J = 7 Hz, 1H, HAr), 7.41 (t,
3J = 7 Hz, 2H, HAr), 7.56 (d, 3J = 7 Hz, 2H, HAr). 13C NMR
(100 MHz, CDCl3): δ 30.2 (C11), 55.8 (OMe), 109.9 (CHAr),
119.8 (CHAr), 123.9 (CHAr), 125.5 (CHAr), 127.0 (CHAr), 127.5
(CHAr), 127.7 (CHAr), 128.6 (CHAr), 129.0 (CAr), 130.6 (CHAr),
Preparation of η5-(3-Hydroxyalkylcyclohexadienyl)Mn(CO)3
Complexes. Complex 25. A solution of complex 23 (0.200 g,
0.61 mmol) and freshly distilled TMEDA (0.147 mL, 0.98 mmol,
1.6 equiv) in 10 mL of THF was cooled to -78 °C. A solution of
nBuLi (1.6 M in hexanes, 0.612 mL, 0.98 mmol, 1.6 equiv) was
slowly added. The mixture was stirred for 1 h at -78 °C before
the addition of 2-thiophenecarboxaldehyde (ThCHO) (0.113
mL, 1.22 mmol, 2 equiv). It was stirred for another hour at -78
°C before being warmed to room temperature and quenched by

1788 Organometallics, Vol. 29, No. 7, 2010
Cetiner et al.
141.5 (CAr), 141.6 (CAr), 144.0 (CAr), 157.7 (CAr). MS (ESI,
positive mode): m/z 281.0995 (M þ Hþ, calcd for C18H17OS:
281.1000).
CDCl3): δ 28.9 (C7), 62.6 (OMe), 115.5 (q, 1JCF = 290 Hz, CF3),
123.5 (CHAr), 123.6 (CHAr), 125.0(CAr), 125.1 (CHAr), 126.3
(CHAr), 135.0 (CAr), 136.0 (CHAr), 141.7 (CAr), 158.1 (CAr),
181.6 (q, 2JCF = 35.5 Hz, CdO). 19F NMR (376 MHz, CDCl3):
δ -73.4 (CF3). MS (ESI, positive mode): m/z 323.0324 (M þ
Compound 28. To a solution of complex 26 (0.242 g, 0.67
mmol) in CH2Cl2 (10 mL) was added Et3N (0.236 mL, 1.7 mmol,
2.6 equiv) and (CF3CO)2O (0.243 mL, 1.7 mmol, 2.6 equiv) at
0 °C. The mixture turned yellow to red and was stirred for 1 h at
room temperature. Then water (30 mL) was added and the
aqueous phase was extracted with CH2Cl2. The organic phase
was washed with water (50 mL) and a saturated solution of NaCl
(50 mL) and dried over MgSO4. After concentration in vacuo,
the crude mixture was purified by flash chromatography on
silica gel to afford 28 (0.060 g, 0.2 mmol, 30%) as a yellow oil.
1H NMR (400 MHz, CDCl3): δ 3.78 (s, 3H, OMe), 4.25 (s,
2H, H7), 6.82 (d, 3J = 3.4 Hz, 1H, HAr), 6.94 (t, 3J = 3.4 Hz, 1H,
HAr), 7.18 (m, 2H, H6 and HAr), 7.51 (d, 3J = 7.6 Hz, 1H, H4 or
H5), 7.62 (d, 3J = 7.6 Hz, 1H, H5 or H4). 13C NMR (100 MHz,
Naþ, calcd for C14H11O2F3NaS, 323.0330). IR (neat): ν (cm-1
1719 (CdO).
)
Acknowledgment. Financial support by CNRS is
ꢁ
kindly acknowledged. We thank the Ministere de l’Edu-
cation Nationale et de la Recherche for a MENRT grant
to D.C.
Supporting Information Available: X-ray crystallographic
data for complexes 5, 8a, and 12a. This material is available
free of charge via the Internet at http://pubs.acs.org.