Studies on the chemistry of manganese tricarbonyl cations of phenol and cresols

Article abstract of DOI:10.1021/om020194m

Treatment of (arene)tricarbonylmanganese cations (arene = phenol, cresol) with nucleophiles affords η⁵-cyclohexadienyl complexes that can be demetalated to give ortho-substituted phenols. Acylation of the phenolic oxygen in the η⁵-cy

Full text of DOI:10.1021/om020194m

Organometallics 2002, 21, 3417-3425
3417
Stu d ies on th e Ch em istr y of Ma n ga n ese Tr ica r bon yl
Ca tion s of P h en ol a n d Cr esols
Hwimin Seo, Si-Geun Lee, Dong Mok Shin, Bog Ki Hong, Sungu Hwang,
Doo Soo Chung, and Young Keun Chung*
School of Chemistry and Center for Molecular Catalysis,
Seoul National University, Seoul 151-747, Korea
Received March 7, 2002
Treatment of (arene)tricarbonylmanganese cations (arene ) phenol, cresol) with nucleo-
philes affords η5-cyclohexadienyl complexes that can be demetalated to give ortho-substituted
phenols. Acylation of the phenolic oxygen in the η5-cyclohexadienyl complexes obtained from
phenol, followed by treatment with acid, gives manganese tricarbonyl cations with
coordinated monosubstituted arenes. Reaction of η5-cyclohexadienyl complexes derived from
ortho- and para-cresol with acid gives meta-substituted toluene manganese tricarbonyl
cations, and those derived from meta-cresol give ortho- and/or para-substituted toluene
manganese complexes depending upon the nucleophiles.
In tr od u ction
(3), and [(η6-m-cresol)Mn(CO)3]BF4 (4). We have dem-
onstrated the use of 3 in the preparation of planar chiral
[(1,3-disubstituted arene)Mn(CO)3]BF4.6 Herein we re-
port a new route for the formation of ortho-substituted
phenols and manganese tricarbonyl cations of mono-
substituted arenes and ortho-, meta-, and para-substi-
tuted toluenes. Recently, Rose et al. reported7 the
preparation of disubstituted arene manganese tricar-
bonyl cations by the Stille coupling reaction between (η5-
halogencyclohexadienyl)Mn(CO)3 and ArSnBu3 in the
presence of Pd2(dba)3 and AsPh3 in DMF.
The use of transition metal compounds in organic
synthesis is useful1 because it can provide pathways for
reactions that are impossible or difficult to achieve by
conventional synthetic methods. Synthetic applications
of arene transition metal complexes have evolved rap-
idly over the last two decades.2 The use of (arene)Mn-
+
(CO)3 complexes in organic synthesis, however, has
remained relatively undeveloped compared to those of
chromium and iron derivatives.3
Manganese complexes of phenol are known,4 but their
chemistry is not well developed. Several years ago,5 we
reported the complex [(η6-C6H5OH)Mn(CO)3]BF4 (1) and
its use in the synthesis of doubly functionalized cyclo-
hexadienyl manganese tricarbonyl complexes. We re-
cently reinitiated the study of 1 and the cresol complexes
[(η6-o-cresol)Mn(CO)3]BF4 (2), [(η6-p-cresol)Mn(CO)3]BF4
Resu lts a n d Discu ssion
Syn th esis of Or th o-Su bstitu ted P h en ols via Nu -
cleop h ilic Ad d ition to [(η6-C6H5OH)Mn (CO)3]BF 4.
We found that nucleophilic addition of RMgBr or RLi
to 1 followed by demetalation led to the isolation of
exclusively ortho-alkylated phenols. Thus, treatment of
1 with 2.4 equiv of nucleophile in THF at 0 °C for 30
min gave adducts 1-2 (eq 1).
(1) (a) Abel, E. W.; Stone, F. G. A.; Wilkinson, G. Comprehensive
Organometallic Chemistry II; Elsevier Science Ltd.: Oxford, 1995; Vol.
12. (b) Hegedus, L. S. Transition Metals in the Synthesis of Complex
Organic Molecules; University Science Books: Mill Valley, CA, 1994.
(c) de Meijere, A., Ed. Chem. Rev. 2000, 100 (8). (d) Beller, M., Bolm,
C., Eds. Transition Metals for Organic Synthesis; Wiley-VCH: Wein-
heim, 1998.
(2) (a) Semmelhack, M. F. In Comprehensive Organic Synthesis;
Semmelhack, M. F., Ed.; Trost, B. M., Fleming, I., Eds.; Pergamon:
Oxford, 1990; Vol. 4, p 517. (b) Semmelhack, M. F. In Comprehensive
Organometallic Chemistry II; Hegedus, L. S., Ed.; Abel, E. W., Stone,
F. G. A., Wilkinson, G., Eds.; Elsevier Science Ltd.: Oxford, 1995; Vol.
12, p 979. (c) Kane-Maguire, L. A. P.; Honig, E. D.; Sweigart, D. A.
Chem. Rev. 1984, 84, 525. (d) Astruc, D. Tetrahedron 1983, 39, 4027.
(e) Abd-El-Aziz, A. S.; Bernardin, S. Coord. Chem. Rev. 2000, 203, 219.
(f) Rose-munch, F.; Gagliardini, V.; Renard, C.; Rose, E. Coord. Chem.
Rev. 1998, 178-180, 249. (g) Zhu, J . P. Synlett 1997, 133. (h) Solladie´-
Cavallo. In Advances in Metal-Oraganic Chemistry; Libeskind, L. S.,
Ed.; J AI: Greenwich, CT, 1989; Vol. 1, p 99. (i) Davies, S. G.; Coote,
S. J .; Goodfellow, C. L. In Advances in Metal-Organic Chemistry;
Libeskind, L. S., Ed.; J AI: Greenwich, CT, 1991; Vol. 2, p 1. (j) Uemura,
M. In Advances in Metal-Organic Chemistry; Liebeskind, L. S., Ed.;
J AI: Greenwich, CT, 1991; Vol. 2, p 195.
(3) (a) Pape, A. R.; Kaliappan, K. P.; Ku¨ndig, E. P. Chem. Rev. 2000,
100, 2917. (b) Pike, R. D.; Sweigart, D. A. Coord. Chem. Rev. 1999,
187, 183. (c) Rose-Munch, F.; Rose, E. Curr. Org. Chem. 1999, 3, 445.
(d) Pike, R. D.; Sweigart, D. A. Synlett 1990, 565.
(4) Bhasin, K. K.; Balkeen, W.; Pauson, P. L. J . Organomet. Chem.
1981, 201, C25.
The first step is deprotonation of 1 to yield the
oxocyclohexadienyl manganese complex 1-1. The acidity
(6) Son, S. U.; Park, K. H.; Seo, H.; Chung, Y. K. Chem. Commun.
2002, 1230.
(5) Lee, S.-G.; Kim, J . A.; Chung, Y. K.; Yoon, T.-S.; Kim, N.-j.; Shin,
W.; Kim, J .; Kim, K. Organometallics 1995, 14, 1023.
(7) Prim, D.; Auffrant, A.; Rose-Munch, F.; Rose, E.; Vaissermann,
J . Organometallics 2001, 20, 1901.
10.1021/om020194m CCC: $22.00 © 2002 American Chemical Society
Publication on Web 07/11/2002

3418 Organometallics, Vol. 21, No. 16, 2002
Seo et al.
of phenol.13 The present study provides a new method-
ology of the synthesis of ortho-alkylated phenols in
reasonable to high yields. This method is conceptually
quite different from the well-known electrophilic sub-
stitution or rearrangements. In this way, the present
study complements known synthetic methods.
Syn th esis of [(Nu -C6H5)Mn (CO)3]BF 4 fr om [(p h e-
n ol)Mn (CO)3]BF 4. Complexes 1-2′ have a carboxylate
group as a substituent, which is a good leaving group
in the presence of acid. Thus, treatment of 1-2′ (Nu )
CF3C6H4, MeOC6H4) with HBF4 afforded [(Nu-C6H5)-
Mn(CO)3]BF4 (eq 2).
Ta ble 1. Yield s of Or th o-Su bstitu ted P h en ols fr om
Rea ction of 1
entry
Nu
MeMgBr
EtMgBr
PhMgBr
n-BuLi
t-BuLi
c-HexMgCl
C5H5FeC5H4Li
4-CF3C6H4MgBr
yield (%)
demet. cond.
Me3NO
Me3NO
MnO2
Me3NO
Me3NO
Me3NO
(H2N)2C(dO)/H2O 2
(H2N)2C(dO)/H2O2
1
2
3
4
5
6
7
8
51a
42a
83b
75b
58b
80b
21b
58b
a
b
Yield by GC. Isolated yield.
+
of phenol coordinated to Mn(CO)3 is known to be
enhanced.5 Complex 1-1 reacts further with the remain-
ing nucleophile to afford 1-2. The nucleophile was found
to attack only at a terminal position of 1-1. Formation
of 1-2 from 1 can be carried out stepwise or via a one-
pot reaction. Although complex 1-2 could be isolated
in a protonated form, it was found that crude 1-2 can
be reacted directly with a demetalating agent to afford
1-3. The demetalating agents trimethylamine N-oxide
(TMANO),8 MnO2,9 and (H2N)2C(dO)‚H2O2 in aceto-
10
nitrile were used. The demetalation reaction was per-
formed under basic conditions; under acidic conditions,
satisfactory yields were not obtained.
New [(monosubstituted arene)Mn(CO)3]BF4 deriva-
tives 1-4-1 (Nu ) p-CF3C6H4) and 1-4-2 (Nu )
p-MeOC6H4) were obtained in useful yields by this
methodology. Several synthetic methods have been
Table 1 gives the yields of the products. In the case
of entries 1 and 2, phenol was detected as one of the
side products, thus accounting for the modest yields
(51% and 42%, respectively). When the nucleophile was
phenyl, butyl, and cyclohexyl (entries 3, 4, and 6), the
yields were high (75-83%). The present method can be
extended to prepare 2-ferrocenylphenol (entry 7), al-
though in low yield. In this case, neither TMANO nor
MnO2 was an effective demetalating agent, but (H2N)2C-
(dO)‚H2O2 was found to be partially successful as a
demetalating agent. Entry 8 shows the general useful-
ness of (H2N)2C(dO)‚H2O2 in the synthesis of aromatic
substituted phenols, even though the yield may not be
high.
Generally, aromatic substituted phenols can be pre-
pared by a metal-mediated coupling reaction with an
aryl halide.11 Usually the scope of the reaction is limited
by the formation of homocoupled byproducts. Lourak et
al.12 have shown that all three possible coupling prod-
ucts are obtained in the synthesis of 2-(4-trifluoro-
methylphenyl)phenol. This presents both a low yield and
a separation problem. By comparison, entry 8 in Table
1 shows that the ortho-substituted phenol was obtained
as the sole product in 58% yield, suggesting that this
reaction may be of general utility.
+
reported for the coordination of arenes to the Mn(CO)3
moiety.14 However, compounds 1-4-1 and 1-4-2 are not
easily obtained by the conventional synthetic methods
due to low regioselectivity when the relevant biphenyl
is reacted with a Mn(CO)3+ source.14 Thus, the present
method will be quite useful for the regioselective
synthesis of biphenyl and related manganese complexes.
Syn th esis of [(meta -su bstitu ted tolu en e)Mn (CO)3]-
BF 4 Com p lexes fr om [(o-cr esol)Mn (CO)3]BF 4 (2)
a n d [(p-cr esol)Mn (CO)3]BF 4 (3). Tricarbonylmanga-
nese complex (2) was synthesized by the reaction of
o-cresol with Mn(CO)5BF4 or with [(naphthalene)Mn-
(CO)3]BF4 in dichloromethane. Treatment of 2 with
t-BuOK in THF led to the isolation of oxocyclohexa-
dienylmanganese complex 2-1 (eq 3).
Nucleophilic addition to 2-1 followed by an addition
of an electrophile led to the isolation of 2-2, showing
that a nucleophile attacks the terminal position of the
dienyl group containing no substituent. Successive
reactions of 2-1 with a nucleophile (Nu-) and acetic
anhydride gave 2-2-1-2-2-6 in relatively high yields.
The nucleophiles were 4-trifluoromethylphenyl, phenyl,
cyclohexyl, tert-butyl, n-butyl, and methyl. The lowest
yield (50%) was obtained when the nucleophile was
MeMgBr. Treatment of 2-2 with HBF4 in dichloro-
methane led to the isolation of [(meta-substituted
arene)Mn(CO)3]BF4 (2-3) in 52-76% yields.
Ortho-functionalized phenols are common in natural
products and serve as industrial intermediates in the
synthesis of agrochemicals and polymers. Thus, there
have been many reports on the selective ortho-alkylation
(8) (a) Shvo, Y.; Hazum, E. Chem. Commun. 1974, 336. (b) Pearson,
A. J .; Srinivasan, K. J . Org. Chem. 1992, 57, 3965.
(9) (a) Hudlicky, M. Oxidation in Organic Chemistry; American
Chemical Society: Washington 1990; p 288. (b) Mashraqui, S.; Keehan,
P. Synth. Commun. 1982, 12, 637.
(10) (a) Heaney, H. Top. Curr. Chem. 1993, 164, 1. (b) Heaney, Y.
Aldrichim. Acta 1993, 26, 35.
(11) (a) Fanta, P. E. Chem. Rev. 1964, 64, 613. (b) Normant, J . F.
Synthesis 1974, 63. (c) Sainsbury, M. Tetrahedron 1980, 36, 3327. (d)
Negishi, E.-L.; King, A. O.; Okukado, N. J . J . Org. Chem. 1977, 42,
1821.
(12) Lourak, M.; Vanderesse, R.; Fort, Y.; Caubere, P. J . Org. Chem.
1989, 54, 4844.
(13) (a) Van De Water, R. W.; Magdziak, D. J .; Chau, J . N.; Pettus,
T. R. R. J . Am. Chem. Soc. 2000, 122, 6502. (b) Trost, B. M.; Toste, F.
D. J . Am. Chem. Soc. 1998, 120, 815. (c) Angle, S. R.; Rainier, J . D.;
Woytowicz, C. J . J . Org. Chem. 1997, 62, 5884. (d) Mitchell, D.; Doecke,
C.; Hay, L. A.; Koenig, T. M.; Wirth, D. D. Tetrahedron Lett. 1995, 36,
5335.
(14) (a) J ackson, J . D.; Villa, S. J .; Bacon, D. S.; Pike, R. D.;
Carpenter, G. B. Organometallics 1994, 13, 3972, and references
therein. (b) Sun, S.; Yeumg, L.; Sweigart, D. A.; Lee, T. Y.; Lee, S. S.;
Chung, Y. K.; Switzer, S. R.; Pike, R. D. Organometallics 1995, 14,
2613.

Mn Tricarbonyl Cations of Phenol and Cresols
Organometallics, Vol. 21, No. 16, 2002 3419
F igu r e 1. ORTEP drawing of 3B (50% probability el-
lipsoids).
solution of the product prepared by using Mn(CO)5BF4
into diethyl ether yielded single crystals suitable for an
X-ray study. Figure 1 shows the ORTEP drawing of the
crystal. Contrary to our expectation, the BF3-substituted
phenoxide compound 3B was obtained instead of a
dimeric compound. Due to the difficulty in the purifica-
tion, we failed to completely characterize the other
compound. However, we could easily assign the other
to 3A when we compared with 1A and 2A. Thus, instead
of two isomeric forms, two different compounds, 3A and
3B, were obtained. Selected bond lengths and angles
are given in Table 3. Compound 3B is found to be an
eclipsed conformation. The bond distance between boron
and oxygen is 1.498(4) Å, which is longer than that (av
1.468 Å) in BO4- and that (1.367 Å) in X2-BOX.16 The
average C-C bond distance in the coordinated arene
ring is 1.409 Å. The metal-carbon distances in the
coordinated arene ring show a pattern in which the
metal atom is significantly closer to C3-C5 than others.
Other numerical parameters of 3B are similar to those
It was expected that (p-cresol)manganese tricarbonyl
complex (3) would be synthesized in the same manner
as [(o-cresol)Mn(CO)3]BF4 (2). Thus, Mn(CO)5BF4 or
[(naphthalene)Mn(CO)3]BF4 in dichloromethane was
heated with p-cresol (eq 4).
of other (arene)Mn(CO)3+ cations.17 When we took a H
1
1
NMR of the crystal used for X-ray diffraction, the H
NMR peaks (δ 6.53 (d) and 5.85 (d)) were consistent with
one of two sets of arene protons mentioned above. Thus,
we can assign the lower-field peaks to 3A and the
higher-field peaks to 3B. Compound 3B is a zwitterionic
complex and insoluble in diethyl ether. In the same way
as in the synthesis of 2-2, treatment of 3-1 with t-BuLi
followed by the addition of acetic anhydride gave 3-2-1
in 86% yield (eq 5).
However, after the reaction, the 1H NMR of the
product in CD3NO2 shows two sets of arene protons (δ
6.64 (d, J ) 7.3 Hz, 2 H), 6.01 (d, J ) 7.3 Hz, 2 H), 2.36
(s, 3 H); 6.53 (d, J ) 7.4 Hz, 2 H), 5.85 (d, J ) 7.4 Hz,
2 H), 2.32 (s, 3 H) ppm). The ratio of the two sets of
resonances was dependent upon the preparation method.
When Mn(CO)5BF4 was used, the ratio was 1.7:1. When
[(naphthalene)Mn(CO)3]BF4 was used, the ratio was 3.4:
1. When the product was deprotoneated by t-BuOK in
THF, compound 3-1 was obtained as the sole product
in 78% yields. These observations suggest that there are
two isomeric forms of 3 in CD3NO2. Maitlis et al.
reported15 the hydrogen-bonded dimeric phenol com-
plex [{MCp*}2{η6-PhO-H‚‚‚‚O(η6-Ph)}[PF6]3 from the
reaction of phenol and [MCp*(acetone)3][PF6]2 (M ) Rh,
Ir). The dimeric compounds were easily deprotonated
to the corresponding η5-oxocyclohexadienyl complexes
[MCp*(η5-C6H5O)]PF6. The situation seems to be quite
similar to ours; even the details are not the same. Thus,
we envisioned that a monomeric (η6-phenol complex)
and a dimeric ({η6-PhO-H‚‚‚‚O(η6-Ph)} complex) species
coexisted in the solution. Diffusion of a nitromethane
No isomeric compounds were observed. In the same
way, compounds 3-2-2 and 3-2-3 were obtained in 88%
and 56% yield, respectively. Treatment of 3-2-1 with
(15) White, C.; Thompson, S. J .; Maitlis, P. M. J . Organomet. Chem.
1977, 127, 415.

3420 Organometallics, Vol. 21, No. 16, 2002
Ta ble 2. Cr ysta l Da ta a n d Str u ctu r e Refin em en t for 3B, 4-3-2, a n d 5-3
Seo et al.
3B
4-3-2
5-3
empirical formula
fw
cryst syst
space group
a, Å
C
10H7BF3MnO4
C16H12BF4MnO3
394.01
monoclinic
P21/a
10.9259(3)
12.0340(3)
13.0645(4)
90
104.592(1)
90
1662.34(8)
4
C19H18BF4MnO3
436.08
monoclinic
P21/n
10.5925(2)
11.8344(3)
15.5621(4)
90
96.581(1)
90
1937.95(8)
4
313.91
monoclinic
P21/n
7.7887(2)
13.1980(4)
11.2573(4)
90
90.843(1)
90
1157.07(6)
4
b, Å
c, Å
R, deg
â, deg
γ, deg
volume, Å3
Z
d(calcd), Mg/m3
θ range, deg
no. tot. collection
no. unique data
no. params refined
R1[I>2σ(I)]
wR2[I>2σ(I)]
R1(all data)
wR2(all data)
gof
1.802
2.38-27.47
4681
2644
624
0.0373
0.1063
0.0506
0.1208
1.179
1.574
1.61-27.51
6716
3807
792
0.0610
0.1622
0.134
0.2089
0.968
1.495
2.17-27.45
7797
4425
888
0.0891
0.2474
0.1209
0.2791
1.073
Ta ble 3. Selected Bon d Dista n ces (Å) a n d An gles (d eg) for 3B, 4-3-2, a n d 5-3
3B
Mn(1)-C(1)
Mn(1)-C(4)
Mn(1)-C(8)
B-O(1)
2.317(3)
2.203(2)
1.825(3)
1.498(4)
Mn(1)-C(2)
Mn(1)-C(5)
Mn(1)-C(9)
O(1)-C(1)
2.197(2)
2.165(2)
1.807(3)
1.309(3)
Mn(1)-C(3)
Mn(1)-C(6)
Mn(1)-C(10)
2.171(3)
2.210(2)
1.826(3)
C(7)-C(4)-Mn(1)
O(1)-C(1)-Mn(1)
F(2)-B-O(1)
130.54(19)
132.05(18)
110.1(2)
C(1)-O(1)-B
F(2)-B-F(1)
124.0(2)
110.8(3)
4-3-2
Mn-C(1)
Mn-C(4)
Mn-C(14)
C(1)-C(8)
2.234(4)
2.174(5)
1.821(6)
1.491(6)
Mn-C(2)
2.204(4)
Mn-C(3)
2.162(4)
2.183(4)
1.814(5)
Mn-C(5)
Mn-C(15)
C(2)-C(7)
2.165(4)
1.809(6)
1.510(5)
Mn-C(6)
Mn-C(16)
C(7)-C(2)-Mn
128.5(3)
C(8)-C(1)-Mn
131.3(3)
5-3
Mn-C(1)
Mn-C(4)
Mn-C(17)
C(1)-C(7)
2.256(4)
2.220(4)
1.813(6)
1.487(6)
Mn-C(2)
Mn-C(5)
Mn-C(18)
C(4)-C(13)
2.201(4)
2.168(4)
1.832(5)
1.535(6)
Mn-C(3)
Mn-C(6)
Mn-C(19)
2.168(4)
2.199(4)
1.823(5)
C(7)-C(1)-Mn
131.1(3)
C(13)-C(4)-Mn
133.5(3)
HBF4‚OMe2 in dichloromethane led to the isolation of
[(3-tert-butyltoluene)Mn(CO)3]BF4 (3-3-1) in 44% yield.
The H NMR of 3-3-1 was the same as that of 2-3-4.
BF 4. We attempted to synthesize tricarbonyl(m-cresol)-
manganese complex (4) in the same way as the synthesis
1
of [(o-cresol)Mn(CO) ]BF4 (2). However, as in the case
3
1
of 3, the H NMR of the product in CD3NO2 shows two
In the same way, [(3-phenyltoluene)Mn(CO)3]BF4 (3-3-2
) 2-3-2) and [(3-thiopenyltoluene)Mn(CO)3]BF4 (3-3-3)
were prepared in 76% and 26% yield, respectively, from
3-2-2 and 3-2-3.
In organic syntheses, there are few direct methods
for the synthesis of meta-substituted toluenes. Thus,
[(m-substituted toluene)Mn(CO)3]BF4 complexes are
rare, and their chemistry is not well developed. Thus,
the present method is complementary to the well-known
synthetic methods and can provide a new methodology
for the synthesis of meta-substituted toluenes starting
from o-cresol or p-cresol.
sets of arene protons in the ratio 2.5:1 (δ 6.74 (br), 5.93-
5.65 (m); 6.61 (t), 5.81-5.78 (m), 5.70 (d)). Purification
gave an analytically pure compound that was assigned
as 4B from elemental analysis data and proton NMR.
This allowed assignment of the lower-field peaks to 4A
and the high-field peaks to 4B as 3A and 3B (eq 6).
Deprotonation of a mixture of 4A and 4B by t-BuOK
gave 4-1 in 72% yield. When 4-1 was treated with t-BuLi
and acetic anhydride, two isomeric forms (a and b) of
4-2-1 were obtained in 84% yield in a ratio of 6:1 (eq 7).
The two isomeric forms a and b were assigned by
1
the inspection of the H NMR spectrum. Treatment of
Rea ction s of [(m -cr esol)Mn (CO)3]BF 4 (4): Syn -
th esis of [(o- or p-su bstitu ted tolu en e)Mn (CO)3]-
4-1 with PhMgBr and acetic anhydride gave 4-2-2 a and
b in 94% yield with a ratio 1:6. When the nucleophile
was MeMgBr, the ratio a to b was 1.1:1 and with
p-MeOC6H4MgBr the b isomer was obtained exclusively.
Thus, the ratio of a to b is sensitive to the nature of the
nucleophile. In the case of t-BuLi and MeMgBr, the
(16) Allen, F. H.; Kennard, O.; Watson, D. G.; Brammer, L.; Orpen,
A. G. J . Chem. Soc., Perkin Trans. 2 1987, S1.
(17) (a) J eong, E.; Chung, Y. K. J . Organomet. Chem. 1992, 434,
225. (b) Gommans, L. H. P.; Main, L.; Nicholson, B. K. J . Organomet.
Chem. 1985, 284, 345.

Mn Tricarbonyl Cations of Phenol and Cresols
Organometallics, Vol. 21, No. 16, 2002 3421
F igu r e 2. ORTEP drawing of 4-3-2 (50% probability
ellipsoids).
results can be explained by steric effects. However, with
PhMgBr and p-MeOC6H4MgBr, the situation is not
simple. We envision that the electronic effect of PhMgBr
and p-MeOC6H4MgBr may play an important role in the
distribution of products.
F igu r e 3. ORTEP drawing of 5-3 (50% probability el-
lipsoids).
To obtain cationic complexes, compounds 4-2-1 and
4-2-2 were treated with HBF4 in dichloromethane.
Recrystallization of the reaction products in nitro-
methane/diethyl ether gave 4-3-1a and 4-3-2b in 50%
and 40% yield, respectively.
tert-butylphenol)Mn(CO)3]BF4 (5) was synthesized by
the reaction of m-tert-butylphenol with Mn(CO)5BF4. As
expected, the steric effect of the tert-butyl group affects
the regioselectvity of nucleophilic addition. Thus, treat-
ment of 5-1 with PhMgBr followed by acetic anhydride
afforded 5-2 as the sole product (eq 8).
1
According to the H NMR spectrum of 4-3-1, only the
para-substituted toluene manganese complex 4-3-1a
existed. Thus, during recrystallization, the ortho-
substituted toluene complex is removed. On the con-
trary, the 1H NMR spectrum of 4-3-2 shows only the
ortho-substituted toluene manganese complex 4-3-2b.
The formation of 4-3-2b was verified by an X-ray crystal
structure determination of the product (Figure 2).
Selected bond distances and angles of 4-3-2b are given
in Table 3. 4-3-2b adopts a staggered conformation. The
metal-carbon distances in the coordinated arene ring
show a pattern in which the metal atom is significantly
closer to C3-C5 than others. The torsion angle between
the phenyl ring and the coordinated arene is 49.1°.
Other numerical parameters of 4-3-2b are similar to
Acid treatment of 5-2 gave 5-3 in 80% yield. The
structure of 5-3 was confirmed by an X-ray diffraction
study (Figure 3). Selected bond distances and angles are
given in Table 3. Complex 5-3 adopts an eclipsed
conformation, with the average C-C bond distance in
the coordinated arene ring being 1.409 Å. The metal-
carbon distances in the coordinated arene ring show a
pattern in which the metal atom is significantly closer
to C3-C5 than the others. The torsion angle between
the phenyl ring and the coordinated arene is 30.5°.
those of other (arene)Mn(CO)3 cations.17
+
Rea ction s of [(m -ter t-bu tylp h en ol)Mn (CO)3]BF 4
(5): Syn th esis of [(1-t-Bu -4-P h -C6H4)Mn (CO)3]BF 4.
As an extension of the chemistry described above, [(m-

3422 Organometallics, Vol. 21, No. 16, 2002
Seo et al.
in air. All solvents were dried and distilled according to
standard methods before use. THF was freshly distilled from
sodium benzophenone ketyl prior to use. Reagents were
purchased from Aldrich Chemical Co. and Strem Chemical Co.
and were used as received. IR spectra were obtained in solution
or measured as films on NaCl by evaporation of solvent. Mass
spectra were recorded with a VG ZAB-E double-focusing mass
spectrometer.
Compounds 1-1, 1-3-1-1-3-6, and 1-3-8 were known com-
pounds.12,19 Formation of these compounds was verified by
comparing GC retention times, NMR, or high-resolution mass
spectra.
Syn th esis of 1-3-1-1-3-8. (a ) A Typ ica l P r oced u r e for
Dem eta la tion Usin g TMANO. To a solution of 1 (0.30 g, 0.94
mmol) in 15 mL of THF at 0 °C was added dropwise cyclo-
hexylmagnesium chloride (2.4 equiv, 2.25 mmol, 1.1 mL of 2
M solution in diethyl ether). After the solution was stirred for
30 min, water (4 or 5 drops) was added to the reaction mixture
to quench any excess nucleophile. Removal of the solvent by
rotary evaporator gave a brownish yellow powder. The powder
was dissolved in 15 mL of acetonitrile, and dried TMANO (3.6
equiv, 3.25 mmol) was added. The resulting solution was
stirred for 12 h at 40 °C, and the reaction mixture extracted
with excess diethyl ether and 1 M HCl. The ether extracts were
dried over anhydrous MgSO4 and evaporated to give a yellow
residue. Purification by chromatography on a silica gel column
eluting with ether/hexane (v/v, 1:20) gave 0.132 g of the
product 1-3-6 (80%) (entry 6 in Table 1).
Other numerical parameters of 5-3 are similar to those
+
of other (arene)Mn(CO)3 cations.17
F a ctor s Affectin g th e F or m a tion of Com p lex(es)
Typ e A a n d /or B. As mentioned above, Maitlis et al.15
reported the hydrogen-bonded dimeric phenol complex
[{MCp*}2{η6-PhO-H‚‚‚‚O(η6-Ph)}[PF6]3 from the reac-
tion of phenol and [MCp*(acetone)3][PF6]2 (M ) Rh, Ir).
Sweigart et al. reported18 the η6-hydroquinone and
catechol complexes of manganese tricarbonyl. According
to the X-ray structure of [(η6-hydroquinone)Mn(CO)3]2-
(SiF6), -OH substitutents are strongly bonded to the
fluorine atoms in the SiF62- anion. On the basis of these
published reports, we did not expect the formation of
the BF3-substituted phenoxide manganese tricarbonyl
complex B in the reaction of Mn(CO)5BF4 with m- and
p-cresol.
Steric and electronic factors due to substituent(s) on
the arene affect the ratio of A to B. In the case of phenol,
complex A was the sole product. It can be expected that
the introduction of a methyl group to arene would
increase the nucleophilicity of the hydroxy group in
reacting with BF4. However, in the case of o-cresol,
complex A was obtained perhaps due to the steric
hindrance of methyl group. With m- or p-cresol, a
mixture of A and B was obtained. With m-tert-butyl-
phenol, complex A was exclusively obtained presumably
due to the steric hindrance of the tert-butyl group. These
observations suggest that the proportion of B could be
increased provided a stronger electron donor was in-
troduced instead of a methyl group. In agreement with
this view, the use of p-methoxyphenol as an arene
source was found to afford complex 6B as the sole
product (eq 9).
(b ) A Typ ica l P r oced u r e for Dem et a la t ion Usin g
(H2N)2C(dO)/H2O2. Ferrocenyllithium (0.80 mmol, in situ
generated from ferrocene and t-BuLi) was added to the solution
of 1 (0.25 g, 0.78 mmol) in 15 mL of THF at 0 °C. (H2N)2C(d
O)/H2O2 (1.5 equiv) was poured into the above solution, and
the resulting solution was stirred for 12 h at 60 °C. After
purification by chromatography on a silica gel column eluting
with ether/hexane (v/v, 1:20), the product 1-3-7 was obtained
in 21% yield (45 mg). 1-3-7 (entry 7 in Table 1): 1H NMR
(CDCl3) δ 7.23-7.20 (m, 2 H), 7.17 (s, OH), 6.96 (d, J ) 8.34
Hz, 1 H), 6.85 (t, J ) 7.38 Hz, 1 H), 4.52 (t, J ) 1.83 Hz, 2 H),
4.42 (t, J ) 1.86 Hz, 2 H), 4.25 (s, Cp) ppm; 13C NMR (CDCl3)
153.4, 131.0, 129.4, 128.3, 127.8, 122.8, 120.2, 115.7, 69.5, 69.1,
67.4 ppm; HRMS (M+) calcd 278.0394, obsd 278.0399.
Syn th esis of 1-2′-1. To a solution of 1-1 (0.46 g, 2.0 mmol)
in THF (10 mL) at -78 °C was added 3.0 mmol of p-CF3C6H4-
MgBr (generated from 4-bromobenzotrifluoride and magne-
sium turnings in ether). The solution was stirred at -78 °C
for 2 h, and acetic anhydride (0.56 mL, 6.0 mmol) was added.
After the solution was stirred for 30 min at room temperature,
it was quenched with a saturated aqueous NH4Cl solution and
extracted with diethyl ether. Chromatography on a silica gel
column eluting with hexane and diethyl ether (v/v, 10:1) gave
The ratio A:B was also dependent upon the synthetic
methods, e.g., the source of manganese carbonyls and
the synthetic procedure. Compared to the case of
Mn(CO)5BF4 as the source of manganese carbonyls, the
use of [(C10H8)Mn(CO)3]BF4 increased the portion of A.
Treatment of p-cresol with AgBF4 for 7 h and then with
Mn(CO)5Br exclusively yielded B in 65% yield. These
observations suggested that complex B would be ob-
tained as a major compound provided the reaction
1
0.73 g (85%) of the product. H NMR (CDCl3): δ 7.48 (d, J )
8.2 Hz, 2 H), 7.08 (d, J ) 7.9 Hz, 2 H), 5.62 (t, J ) 5.9 Hz, 1
H), 5.29 (d, J ) 5.5 Hz, 1 H), 4.87 (t, J ) 6.1 Hz, 1 H), 4.54 (d,
J ) 6.6 Hz, 1 H), 3.62 (t, J ) 6.3 Hz, 1 H), 2.07 (s, 3 H) ppm.
-
between cresol and BF4 anion took place before the
formation of complex A.
In conclusion, we have demonstrated the usefulness
of cationic manganese tricarbonyl complexes of phenol
and cresols in the preparation of ortho-substituted
phenols. Also presented are related procedures for the
synthesis of manganese tricarbonyl complexes of mono-
substituted arene and ortho-, meta-, and para-substi-
tuted toluenes. The general methodology described may
have significant applications in organic and organo-
metallic synthesis.
IR (Et2O): νCO 2020, 1944 cm-1 13C NMR (CDCl3): 221.8,
.
168.5, 147.3, 129.3, 126.4, 125.5, 121.5, 100.8, 93.9, 89.5, 72.4,
58.7, 46.0, 21.3 ppm. HRMS (M+): calcd 420.0017, obsd
420.0020.
1-2′-2. Yield: 79%. 1H NMR (CDCl3): δ 6.88 (d, J ) 8.6 Hz,
2 H), 6.74 (d, J ) 8.6 Hz, 2 H), 5.59 (t, J ) 4.9 Hz, 1 H), 5.22
(d, J ) 5.8 Hz, 1 H), 4.84 (t, J ) 6.1 Hz, 1 H), 4.40 (d, J ) 6.2
Hz, 1 H), 3.74 (s, 3 H), 3.65 (t, J ) 6.2 Hz, 1 H), 2.05 (s, 3 H)
ppm. IR (Et2O): νCO 2016, 1939 cm-1 13C NMR (CDCl3): 222.2,
.
168.9, 159.3, 137.3, 127.7, 114.0, 103.5, 94.1, 89.5, 72.3, 61.3,
55.6, 46.2, 21.8 ppm. HRMS (M+): calcd 382.0249, obsd
382.0250.
Exp er im en ta l Section
Gen er a l. All reactions were conducted under nitrogen using
standard Schlenk-type flasks. Workup procedures were done
(19) Dewar, M. J . C.; Puttnam, N. A. J . Chem. Soc. 1959, 4080.
Kolka, A. J . J . Org. Chem. 1957, 22, 642. The Aldrich Library of 13C
and 1H FT NMR spectra: 1(2)245(A) and 1(2)317(A).
(18) Sun, S.; Carpenter, G. B.; Sweigart, D. A. J . Organomet. Chem.
1996, 512, 257.

Mn Tricarbonyl Cations of Phenol and Cresols
Organometallics, Vol. 21, No. 16, 2002 3423
Syn th esis of 1-4-1. To a solution of 1-2′-1 (0.25 g, 0.59
mmol) in 10 mL of CH2Cl2 was added HBF4‚OEt2 (0.11 mL,
1.5 equiv) at -78 °C. After the solution was stirred for 2 h,
K2CO3 (0.25 g, 3 equiv) was added to the solution. The
resulting solution was allowed to warm to room temperature.
Nitromethane (1-2 mL) was added to dissolve the salt, and
the solution was filtered over Celite. Excess diethyl ether (50
mL) was added to the filtrate to precipitate 1-4-1 (80 mg, 31%).
1H NMR (CDCl3): δ 8.29 (d, J ) 8.3 Hz, 2 H), 8.01 (d, J ) 8.3
Hz, 2 H), 7.41 (d, J ) 6.7 Hz, 2 H), 7.23 (t, J ) 6.9 Hz, 2 H),
6.96 (t, J ) 6.6 Hz, 1 H) ppm. IR (CH3NO2): νCO 2072, 2024
cm-1. Anal. Calcd for C16H9BF7MnO3: C, 42.86; H, 2.02.
Found: C, 43.14; H, 1.96.
(s, 9 H) ppm. IR (CH2Cl2): νCO 2020, 1940, 1765 cm-1. Anal.
Calcd for C16H19MnO5: C, 55.50; H, 5.53. Found: C, 55.65; H,
5.40.
1
2-2-5. Yield: 85%. H NMR (CDCl3): δ 5.46 (d, J ) 5.0 Hz,
1 H), 4.65 (dd, J ) 5.1, 7.1 Hz, 1 H), 3.40 (dd, J ) 6.1, 7.3 Hz,
1 H), 3.21-3.18 (m, 1 H), 2.12 (s, 3 H), 1.85 (s, 3 H), 0.97-
0.86 (m, 6 H), 0.80 (t, 7.0 Hz, 3 H) ppm. IR (CH2Cl2): νCO 2016,
1941, 1763 cm-1. Anal. Calcd for C16H19MnO5: C, 55.50; H,
5.53. Found: C, 55.59; H, 5.73.
1
2-2-6. Yield: 50%. H NMR (CDCl3): δ 5.49 (d, J ) 5.1 Hz,
1 H), 4.63 (dd, J ) 5.1, 7.0 Hz, 1 H), 3.36 (dd, J ) 5.9, 7.5 Hz,
1 H), 3.22-3.17 (m, 1 H), 2.13 (s, 3 H), 1.85 (s, 3 H), 0.54 (d,
J ) 6.4 Hz, 3H) ppm. IR (CH2Cl2): νCO 2016, 1934, 1761 cm-1
.
Anal. Calcd for C13H13MnO5: C, 51.33; H, 4.31. Found: C,
51.62; H, 4.41.
1
1-4-2. Yield: 47%. H NMR (CDCl3): δ 8.03 (d, J ) 8.8 Hz,
2 H), 7.25-7.18 (m, 6 H), 6.75 (t, J ) 6.0 Hz, 1H), 3.93 (s, 3 H)
Syn th esis of 2-3-1-2-3-6. To a solution of 2-2 in (0.5 mmol)
in 5 mL of CH2Cl2 was added 3 equiv of HBF4‚OMe2. After
the solution was stirred for 1.5 h, 4 equiv of K2CO3 was added
to the reaction mixture. Filtration through Celite followed by
recrystallization in dichloromethane/diethyl ether gave the
product 2-3.
ppm. IR (CH3NO2): νCO 2072, 2024 cm-1. Anal. Calcd for
C
18H15MnO6: C, 46.83; H, 2.95. Found: C, 46.54; H, 2.91.
Syn th esis of [(o-cr esol)Mn (CO)3]BF 4 (2). o-Cresol (2.3
mL, 22.0 mmol) was added to a solution of Mn(CO)5BF4 in 50
mL of CH2Cl2 (generated by the reaction of Mn(CO)5Br (3.0 g,
11.0 mmol) and AgBF4 (2.4 g, 12.0 mmol) in CH2Cl2). The
resulting solution was heated at reflux for 12 h. Evaporation
followed by recrystallization in dichloromethane/diethyl ether
gave 2 in 82% yield (3.0 g). 1H NMR (CD3NO2): δ 6.94 (d, J )
5.2 Hz, 1 H), 6.76 (t, J ) 6.7 Hz, 1 H), 6.16 (d, J ) 7.8 Hz, 1
H), 5.99 (t, J ) 5.7 Hz, 1 H), 2.30 (s, 3 H) ppm. IR (CH2Cl2):
1
2-3-1. Yield: 76%. H NMR (acetone-d6): δ 8.32 (d, J ) 8.1
Hz, 2 H), 8.00 (d, J ) 8.1 Hz, 2 H), 7.28 (s, 1 H), 7.24 (t, J )
6.6 Hz, 1 H), 7.17 (d, J ) 6.6 Hz, 1 H), 6.74 (d, J ) 6.25 Hz, 1
H), 2.77 (s, 3 H) ppm. IR: νCO 2072, 2012 cm-1. Anal. Calcd
for C17H11BF7MnO3: C, 44.20; H, 2.40. Found: C, 43.99; H,
2.36.
ν
CO 2060, 1997 cm-1. Anal. Calcd for C10H8BF4MnO4: C, 35.97;
2-3-2. Yield: 56%. 1H NMR (CD3NO2): δ 7.91 (d, J ) 6.4
Hz, 2 H), 7.67 (br, 3 H), 6.94 (t, J ) 6.4 Hz, 1 H), 6.79 (m, 2
H), 6.36 (d, J ) 5.9 Hz, 1 H), 2.68 (s, 3 H) ppm. IR: νCO 2080,
2016 cm-1. Anal. Calcd for C16H12BF4MnO3: C, 48.77; H, 3.07.
Found: C, 48.48; H, 3.05.
H, 2.41. Found: C, 36.14; H, 2.35.
Syn th esis of 2-1. To a solution of 2 (1.0 g, 3.6 mmol) in 20
mL of THF was added t-BuOK (0.40 g, 3.6 mmol) in THF. The
solution was stirred for 1 h. Evaporation followed by chroma-
tography on a silica gel column eluting with ethyl acetate gave
1
2-3-3. Yield: 70%. H NMR (acetone-d6): δ 6.91 (t, J ) 6.5
1
2-1 in 99% yield (0.88 g). H NMR (CDCl3): δ 5.96 (d, J ) 5.5
Hz, 1 H), 6.71 (s, 1 H), 6.64 (d, J ) 8.5 Hz, 1H), 6.61(d, J )
7.7 Hz, 1H), 2.73 (t, J ) 11.6 Hz, 1 H), 2.60 (s, 3 H), 2.05 (m,
2 H), 1.90 (d, J ) 11.0 Hz, 2 H), 1.76 (d, J ) 12.8 Hz, 1 H),
1.61-1.45 (m, 4 H), 1.25 (m, 1 H) ppm. IR: νCO 2080, 2016
cm-1. Anal. Calcd for C16H18BF4MnO3: C, 48.04; H, 4.54.
Found: C, 48.07; H, 4.54.
Hz, 1 H), 5.86 (t, J ) 6.6 Hz, 1 H), 5.18 (t, J ) 5.7 Hz, 1 H),
4.86 (d, J ) 7.2 Hz, 1H), 2.03 (s, 3 H) ppm. IR (CH2Cl2): νCO
2040, 1966 cm-1. Anal. Calcd for C10H7MnO4: C, 48.81; H, 2.87.
Found: C, 48.56; H, 2.95.
Syn th esis of 2-2-1-2-2-7. Typ ica l P r oced u r es. To a
solution of 2-1 (0.30 g, 1.2 mmol) in 20 mL of THF was added
nucleophile (2.4 mmol) at 0 °C. After the solution was stirred
at 0 °C for 1 h, acetic anhydride (1.0 mL, 10.5 mmol) was added
to the solution. The solution was allowed to warm to room
temperature and stirred at room temperature for 1 h. Excess
diethyl ether (50 mL) and water (30 mL) were added to quench
the reaction, and the ether layer was separated, evaporated
to dryness, and chromatographed on a silica gel column eluting
with ethyl acetate and hexane (v/v, 1:20). Removal of the
solvent gave the product 2-2.
2-3-4. Yield: 61%. 1H NMR (CD3NO2): δ 6.59-6.55 (m, 3
H), 6.46 (d, J ) 5.1 Hz, 1 H), 2.54 (s, 3 H), 1.47 (s, 9 H) ppm.
IR: νCO 2072, 2012 cm-1. Anal. Calcd for C14H16BF4MnO3: C,
44.96; H, 4.31. Found: C, 44.96; H, 4.33.
1
2-3-5. Yield: 52%. H NMR (acetone-d6): δ 6.99 (t, J ) 6.6
Hz, 1 H), 6.63 (s, 1 H), 6.54 (d, J ) 6.4 Hz, 2 H), 2.84 (m, 2 H),
2.61 (s, 3 H), 1.76 (m, 2 H), 1.49 (m, 2 H), 0.95 (t, J ) 7.3 Hz,
3 H) ppm. IR: νCO 2082, 2016 cm-1. Anal. Calcd for C14H16
-
BF4MnO3: C, 44.96; H, 4.31. Found: C, 45.12; H, 4.33.
1
2-3-6. Yield: 67%. H NMR (acetone-d6): δ 6.96 (t, J ) 6.6
Hz, 1 H), 6.59 (s, 1 H), 6.48 (d, J ) 6.5 Hz, 2 H), 2.60 (s, 6 H)
ppm. IR: νCO 2080, 2016 cm-1. Anal. Calcd for C11H10BF4-
MnO3: C, 39.80; H, 3.04. Found: C, 39.76; H, 2.98.
1
2-2-1. Yield: 85%. H NMR (CDCl3): δ 7.48 (d, J ) 8.1 Hz,
2 H), 7.01 (d, J ) 8.0 Hz, 2 H), 5.55 (d, J ) 5.1 Hz, 1 H), 4.81
(dd, J ) 5.2, 7.0 Hz, 1 H), 4.70 (d, J ) 6.3 Hz, 1 H), 3.62 (dd,
J ) 6.4, 7.1 Hz, 1 H), 2.09 (s, 3 H), 1.98 (s, 3 H) ppm. IR
(CH2Cl2): νCO 2016, 1931, 1748 cm-1. Anal. Calcd for C19H14F3-
MnO5: C, 52.55; H, 3.25. Found: C, 52.78; H, 3.25.
Syn th esis of a Mixtu r e of 3A a n d 3B. Meth od A.
p-Cresol (0.82 mL, 7.8 mmol) was added to the solution of
Mn(CO)5BF4 in 20 mL of CH2Cl2 (generated by the reaction of
Mn(CO)5Br (1.4 g, 5.1 mmol) and AgBF4 (1.1 g, 5.7 mmol) in
CH2Cl2). The resulting solution was heated at reflux for 5 h.
After the solution was cooled to room temperature, nitro-
methane (2-3 mL) was added to dissolve salts. Filtration
followed by recrystallization with diethyl ether gave a mixture
of 3A and 3B in a ratio 1.7:1 (1.35 g). IR (CH3NO2): νCO 2064,
1
2-2-2. Yield: 83%. H NMR (CDCl3): δ 7.22-7.17 (m, 3 H),
6.89 (d, J ) 9.2 Hz, 2 H), 5.52 (d, J ) 5.1 Hz, 1 H), 4.79 (dd,
J ) 5.1, 7.2 Hz, 1 H), 4.65 (d, J ) 6.3 Hz, 1 H), 3.67 (dd, J )
6.4, 7.2 Hz, 1 H), 2.08 (s, 3 H), 1.99 (s, 3 H) ppm. IR (CH2Cl2):
νCO 2012, 1938, 1746 cm-1. Anal. Calcd for C18H15MnO5: C,
59.03; H, 4.13. Found: C, 59.00; H, 4.17.
1
2006 cm-1. H NMR (CD3NO2) of 3A: δ 6.64 (d, J ) 7.2 Hz, 2
1
H), 6.01 (d, J ) 7.3 Hz, 2 H), 2.36 (s, 3 H) ppm. 1H NMR
(CD3NO2) of 3B: δ 6.53 (d, J ) 7.5 Hz, 2 H), 5.85 (d, J ) 7.4
Hz, 2 H), 2.32 (s, 3 H) ppm. Anal. Calcd for C10H7BF3MnO4
(3B): C, 38.26; H, 2.25. Found: C, 38.03; H, 2.22.
Met h od B. [(C10H8)Mn(CO)3]BF4 was used instead of
Mn(CO)5Br, and a mixture of 3A and 3B was obtained in a
ratio 3.4:1.
2-2-3. Yield: 70%. H NMR (CDCl3): δ 5.40 (d, J ) 5.0 Hz,
1 H), 4.66 (dd, J ) 5.0, 6.7 Hz, 1 H), 3.37 (dd, J ) 5.8, 7.5 Hz,
1 H), 3.30 (t, J ) 5.8 Hz, 1 H), 2.10 (s, 3 H), 1.90 (s, 3 H),
1.63-0.62 (m, 11 H) ppm. IR (CH2Cl2): νCO 2016, 1936, 1748
cm-1. Anal. Calcd for C18H21MnO5: C, 58.07; H, 5.69. Found:
C, 58.21; H, 5.78.
1
2-2-4. Yield: 76%. H NMR (CDCl3): δ 5.36 (d, J ) 5.0 Hz,
1 H), 4.70 (dd, J ) 5.0, 7.2 Hz, 1 H), 3.54 (d, J ) 6.3 Hz, 1 H),
3.38 (dd, J ) 6.6, 7.2 Hz, 1 H), 2.08 (s, 3 H), 1.93 (s, 3 H), 0.60
Meth od C. A solution of p-cresol (0.20 mL, 2.0 mmol) and
AgBF4 (0.39 g, 2.0 mmol) in 15 mL of CH2Cl2 was heated at

3424 Organometallics, Vol. 21, No. 16, 2002
Seo et al.
reflux for 7 h. To the solution was added Mn(CO)5Br (0.54 g,
2.0 mmol). The reaction mixture was heated at reflux for 12
h. Filtration and recrystallization gave 0.41 g (65%) of 3B only.
Syn th esis of 3-1. To the solution of a mixture of 3A and
3B (0.61 g, 1.8 mmol) in 15 mL of THF at -78 °C was added
t-BuOK (0.26 g, 2.3 mmol). The solution was allowed to warm
to room temperature for 1 h. After the solution was filtered
over Celite, the filtrate was chromatographed on a silica gel
column eluting with ethyl acetate and acetone (v/v, 1:2).
Removal of the solvent gave 3-1 in 74% yield (0.34 g). 1H NMR
(CDCl3): δ 5.93 (br, 2 H), 4.81 (br, 2 H), 2.30 (s, 3 H) ppm. IR
(CH3NO2): νCO 2036, 1966 cm-1. Anal. Calcd for C10H7MnO4:
C, 48.81; H, 2.87. Found: C, 48.35; H, 2.85.
Syn th esis of 4-2-1. To the solution of 4-1 (0.47 g, 1.9 mmol)
in 15 mL of THF at -78 °C was added t-BuLi (2.3 mL in 1.7
M pentane, 3.9 mmol). The solution was stirred at -78 °C for
2 h. To the resulting solution was added acetic anhydride (0.45
mL, 4.8 mmol). After the solution was allowed to warm to room
temperature, the solution was quenched with aqueous NH4Cl
solution (30 mL) and diethyl ether (50 mL). The ether layer
was dried over anhydrous MgSO4, concentrated, and chro-
matographed on a silica gel column eluting with hexane and
diethyl ether (v/v, 20:1). Yield: 84% (0.57 g). 1H NMR (acetone-
d6) of a : δ 5.44 (s, 1 H), 5.06 (d, J ) 7.2 Hz, 1 H), 3.44 (t, J )
6.8 Hz, 1 H), 3.26 (d, J ) 5.5 Hz, 1 H), 2.48 (s, 3 H), 2.05 (s, 3
1
H), 0.64 (s, 9 H) ppm. H NMR (acetone-d6) of b: δ 5.57 (t, J
) 5.5 Hz, 1 H), 5.38 (d, J ) 5.9 Hz, 1 H), 4.86 (d, J ) 4.8 Hz,
Syn th esis of 3-2-1. To the solution of 3-1 (0.35 g, 1.4 mmol)
in 15 mL of THF at -78 °C was added t-BuLi (1.7 mL, 2.9
mmol). The solution was stirred at -78 °C for 20 min and
allowed to warm to room temperature for 1 h. To the resulting
solution was added acetic anhydride (0.45 mL, 4.8 mmol). After
the solution was stirred for 30 min, the solution was quenched
with aqueous NH4Cl solution (30 mL) and diethyl ether (50
mL). The ether layer was dried over anhydrous MgSO4,
concentrated, and chromatographed on a silica gel column
eluting with hexane and diethyl ether (v/v, 20:1). Yield: 86%
(0.43 g). 1H NMR (CDCl3): δ 5.29 (d, J ) 5.1 Hz, 1 H), 5.18 (d,
J ) 5.8 Hz, 1 H), 3.23 (s, 2 H), 2.06 (s, 3 H), 1.88 (s, 3 H), 0.61
(s, 9 H) ppm. IR (Et2O): νCO 2012, 1924 cm-1. Anal. Calcd for
C16H19MnO5: C, 55.50; H, 5.53. Found: C, 55.79; H, 5.61.
1 H), 3.44 (s, 1 H), 2.00 (s, 3 H), 1.85 (s, 3 H), 0.72 (s, 9 H)
ppm. IR (Et2O): νCO 2012, 1927 cm-1. Anal. Calcd for C16H19
-
MnO5: C, 55.50; H, 5.53. Found: C, 55.79; H, 5.61.
1
4-2-2. Yield: 94%. H NMR (CDCl3) of a -isomer: δ 7.96 (d,
J ) 7.4 Hz, 2 H), 7.47 (m, 3 H), 5.32 (s, 1 H), 4.88 (d, J ) 6.8
Hz, 1 H), 4.10 (t, J ) 6.1 Hz, 1 H), 3.56 (d, J ) 6.9 Hz, 1 H),
1
2.61 (s, 3 H), 1.58 (s, 3 H) ppm. H NMR (CDCl3) of b-isomer:
δ 7.23 (m, 3 H), 6.95 (d, J ) 5.7 Hz, 2 H), 5.50 (t, J ) 5.1 Hz,
1 H), 5.19 (d, J ) 5.2 Hz, 1 H), 4.63 (d, J ) 4.3 Hz, 1 H), 4.46
(s, 1 H), 2.04 (s, 3 H), 1.71 (s, 3 H) ppm. IR (Et2O): νCO 2010,
1930 cm-1. Anal. Calcd for C18H15MnO5: C, 59.03; H, 4.13.
Found: C, 58.61; H, 4.05.
1
4-2-3. Yield: 69%. H NMR (CDCl3) of a -isomer: δ 5.08 (s,
1
3-2-2. Yield: 88% (1.06 g). H NMR (CDCl3): δ 7.23 (m, 3
1 H), 4.71 (d, J ) 7.1 Hz, 1 H), 3.30 (t, J ) 6.5 Hz, 1 H), 3.12-
3.05 (m, 1 H), 2.50 (s, 3 H), 2.11 (s, 3 H), 0.53 (d, J ) 6.4 Hz,
3 H) ppm. 1H NMR (CDCl3) of b-isomer: δ 5.45 (t, J ) 5.3 Hz,
1 H), 4.98 (d, J ) 5.6 Hz, 1 H), 4.43 (d, J ) 5.0 Hz, 1 H), 3.19
(d, J ) 6.3 Hz, 1 H), 2.11 (s, 3 H), 1.73 (s, 3 H), 0.58 (d, J )
6.4 Hz, 3 H) ppm. IR (Et2O): νCO 2010, 1936 cm-1. Anal. Calcd
for C13H13MnO5: C, 51.33; H, 4.31. Found: C, 51.56; H, 4.34.
H), 6.92 (d, J ) 6.9 Hz, 2 H), 5.46 (d, J ) 4.5 Hz, 1 H), 5.20 (d,
J ) 5.5 Hz, 1 H), 4.46 (d, J ) 5.4 Hz, 1 H), 3.55 (d, J ) 4.8 Hz,
1 H), 2.05 (s, 3 H), 1.92 (s, 3 H) ppm. IR (Et2O): νCO 2016,
1929 cm-1. Anal. Calcd for C18H15MnO5: C, 59.03; H, 4.13.
Found: C, 58.80; H, 4.14.
3-2-3. Yield: 0.25 g (56%). 1H NMR (CDCl3): δ 7.00 (d, J )
4.4 Hz, 1 H), 6.75 (dd, J ) 3.5, 4.7 Hz, 1 H), 6.50 (d, J ) 3.3
Hz, 1 H), 5.45 (d, J ) 3.1 Hz, 1 H), 5.07 (d, J ) 4.5 Hz, 1 H),
4.54 (d, J ) 6.1 Hz, 1 H), 3.52 (d, J ) 5.0 Hz, 1 H), 1.99 (s, 3
H), 1.87 (s, 3 H) ppm. 13C NMR (CDCl3): δ 221.09, 168.52,
126.52, 125.87, 124.33, 123.09, 109.12, 102.16, 87.16, 73.81,
1
4-2-4. Yield: 85%. H NMR (CDCl3): δ 6.96 (d, J ) 8.7 Hz,
2 H), 6.79 (d, J ) 8.8 Hz, 2 H), 5.78 (t, J ) 5.3 Hz, 1 H), 5.34
(d, J ) 5.3 Hz, 1 H), 4.93 (d, J ) 5.2 Hz, 1 H), 4.40 (s, 1 H),
3.74 (s, 3 H), 2.02 (s, 3 H), 1.71 (s, 3 H) ppm. IR (Et2O): νCO
2010, 1938 cm-1. Anal. Calcd for C19H17MnO6: C, 57.59; H,
4.32. Found: C, 57.93; H, 4.42.
60.62, 42.34, 21.96, 21.37 ppm. IR (Et2O): νCO 2016, 1930 cm-1
.
HRMS (M+) calcd 371.9864, obsd 371.9866.
4-3-1. The same procedure as the synthesis of 3-3 was
applied. Yield: 50%. 1H NMR (CD3NO2): δ 6.85 (d, J ) 7.1
Hz, 2 H), 6.27 (d, J ) 7.1 Hz, 2 H), 2.55 (s, 3 H), 1.45 (s, 9 H)
ppm. IR (CH3NO2): νCO 2068, 2012 cm-1. Anal. Calcd for
Syn th esis of 3-3-1. To the solution of 3-2-1 (0.93 g, 1.2
mmol) in 10 mL of CH2Cl2 at -78 °C was added HBF4‚OMe2
(0.22 mL, 1.8 mmol). After the solution was stirred for 2 h,
K2CO3 (0.66 g, 4.8 mmol) was added to the solution. The
resulting solution was allowed to warm to room temperature.
Nitromethane (1-2 mL) was added to dissolve the salt, and
the solution was filtered over Celite. Excess diethyl ether (50
mL) was added to the filtrate to precipitate 3-3-1 in 44% yield
C
14H16BF4MnO3: C, 44.96; H, 4.31. Found: C, 45.08; H, 4.43.
4-3-2. Yield: 40%. 1H NMR (CD3NO2): δ 7.61 (m, 5 H), 6.79
(m, 2 H), 6.55 (m, 2 H), 2.53 (s, 3 H) ppm. IR (CH3NO2): νCO
2070, 2014 cm-1. Anal. Calcd for C16H12BF4MnO3: C, 48.77;
H, 3.07. Found: C, 48.78; H, 3.10.
1
(0.20 g). The H NMR of 3-3-1 was the same as that of 2-3-4.
Syn th esis of 5. It was prepared by method A of the
3-3-2. Yield: 76% (0.75 g). The 1H NMR of 3-3-2 was the
same as that of 2-3-2.
1
synthesis of 3. Yield: 69%. H NMR (acetone-d6): δ 6.89 (t, J
) 6.7 Hz, 1 H), 6.11 (d, J ) 6.7 Hz, 1 H), 6.05 (s, 1 H), 6.04 (d,
J ) 7.7 Hz, 1 H), 1.49 (s, 9 H) ppm. IR (CH3NO2): νCO 2060,
2000 cm-1. Anal. Calcd for C10H7BF3MnO5: C, 36.41; H, 2.14.
Found: C, 36.47; H, 2.17.
3-3-3. Yield: 26%. 1H NMR (CD3NO2): δ 7.92 (d, J ) 3.8
Hz, 1 H), 7.86 (d, J ) 3.9 Hz, 1 H), 7.31 (dd, J ) 3.82, 3.86 Hz,
1 H), 6.90 (t, J ) 6.7 Hz, 1 H), 6.70 (s, 1 H), 6.65 (d, J ) 6.7
Hz, 1 H), 6.22 (d, J ) 6.8 Hz, 1 H), 2.64 (s, 3 H) ppm. IR
(CH3NO2): νCO 2068, 2014 cm-1. Anal. Calcd for C14H10BF4-
MnO3S: C, 42.04; H, 2.52; S, 8.01. Found: C, 41.96; H, 2.48;
S, 8.29.
5-1. The same procedure as the synthesis of 3-1 was applied.
1
Yield: 97%. H NMR (CDCl3): δ 5.99 (br s, 1 H), 5.30 (br s, 1
H), 5.04 (br s, 1 H), 4.85 (br s, 1 H), 1.32 (s, 9 H) ppm. IR
(CH3NO2): νCO 2036, 1966 cm-1. Anal. Calcd for C13H13MnO4:
C, 54.18; H, 4.55. Found: C, 54.00; H, 4.79.
Syn th esis of a Mixtu r e of 4A a n d 4B. The same proce-
dure as the synthesis of a mixture of 3A and 3B was applied
except with m-cresol instead of p-cresol. After the reaction, a
mixture of 4A and 4B was obtained in a ratio 5:2.
5-2. The same procedure as the synthesis of 3-2-2 was
1
applied. Yield: 65%. H NMR (CDCl3): δ 7.20 (m, 3 H), 6.94
1
(d, J ) 6.3 Hz, 2 H), 5.31 (s, 1 H), 4.91 (d, J ) 7.3 Hz, 1 H),
4.51 (d, J ) 5.9 Hz, 1 H), 3.57 (t, J ) 6.9 Hz, 1 H), 2.05 (s, 3
H), 1.49 (s, 9 H) ppm. IR (Et2O): νCO 2008, 1918 cm-1. Anal.
Calcd for C21H21MnO5: C, 61.77; H, 5.18. Found: C, 61.89; H,
5.31.
5-3. The same procedure as the synthesis of 3-3 was applied.
Yield: 80%. 1H NMR (acetone-d6): δ 8.09 (d, J ) 7.9 Hz, 2 H),
7.69 (m, 3 H), 7.42 (d, J ) 7.4 Hz, 2 H), 7.14 (d, J ) 7.4 Hz, 2
4-B. H NMR (CD3NO2): δ 6.65 (t, J ) 6.7 Hz, 1 H), 5.81-
5.78 (m, 2 H), 5.70 (d, J ) 6.3 Hz, 1 H), 2.30 (s, 3 H) ppm. IR
(CH3NO2): νCO 2064, 2004 cm-1. Anal. Calcd for C10H8BF4-
MnO4: C, 38.26; H, 2.25. Found: C, 38.67; H, 2.40.
Syn th esis of 4-1. Yield: 63%. 1H NMR (acetone-d6): δ 6.31
(br, 1 H), 5.59 (br, 1 H), 4.80 (br, 1 H), 4.73 (s, 1 H), 2.23 (s, 3
H) ppm. IR (CH3NO2): νCO 2036, 1965 cm-1. Anal. Calcd for
C
10H7MnO4: C, 48.81; H, 2.87. Found: C, 49.09; H, 2.89.

Mn Tricarbonyl Cations of Phenol and Cresols
Organometallics, Vol. 21, No. 16, 2002 3425
H), 1.56 (s, 9 H) ppm. IR (CH3NO2): νCO 2064, 2000 cm-1. Anal.
Calcd for C19H18BF4MnO3: C, 52.33; H, 4.16. Found: C, 52.23;
H, 4.20.
Syn th esis of 6. The same procedure as the synthesis of a
mixture of 3A and 3B was applied except with p-methoxy-
phenol instead of p-cresol. Only isomer B was obtained. 1H
(CD3NO2): δ 6.25 (d, J ) 7.8 Hz, 2 H), 6.07 (d, J ) 7.7 Hz, 2
H), 3.93 (s, 3 H) ppm. IR (CH3NO2): νCO 2064, 2004 cm-1. Anal.
Calcd for C13H14BF4MnO4: C, 41.53; H, 3.75. Found: C, 41.88;
H, 3.81.
X-r a y Da ta Collection , Str u ctu r e Deter m in a tion , a n d
Refin em en t for Com p ou n d s 3B, 4-3-2, a n d 5-3. Crystal
data, details of the data collection, and refinement parameters
are listed in Table 2. Selected bond distances and angles are
given in Table 3.
Ack n ow led gm en t . Y.K.C. is grateful for the fi-
nancial support from KOSEF (1999-1-122-001-5) and
the KOSEF through the Center for Molecular Cataly-
sis at Seoul National University, and H.S. and
D.M.S. acknowledge receipt of the Brain Korea 21
fellowship.
Su ppor tin g In for m ation Available: Tables giving atomic
positions, anisotropic thermal parameters, and bond lengths
and angles for 3B and 4-3-2. This material is available free of
charge via the Internet at http://pubs.acs.org. Structure factor
tables are available from the authors.
OM020194M