Models for the homogeneous hydrodesulfurization of thiophenes: Manganese-mediated carbon-sulfur bond cleavage and hydrogenation reactions

Article abstract of DOI:10.1021/om970822d

Chemical reduction of a series of (η⁵-thiophene)Mn(CO)₃⁺ complexes (3a-d) under an atmosphere of CO affords dimanganese metallathiacyclic complexes (4a-d), which have a Mn(CO)₄ moiety regioselectively inserted into a C-S bond. Reaction of 4 with H₂, the rate of which is strongly influenced by substituents on the thiophene ring, leads to hydrogenolysis of the Mn-C σ-bond and formation of (OC)₃Mn(μ-H)(μ-SCRCHCHCHR′)Mn(CO)₃ (8; R, R′ = H, Me), which contains bridging hydride and thiolate ligands and a Mn-Mn bond. The addition of PhMgBr to 3 occurs at the sulfur to give zwitterionic complexes (6a-c, 14), which undergo regioselective hydrogenolysis of a C-S bond and, in some cases, partial desulfurization with concomitant formation of (OC)₄Mn(μ-H)(μ-SPh)Mn(CO)₄ (5a). Crystal structures are reported for complexes 4b,d, 5a, 8d, 10, 12c, and 14b,c. It is suggested that the reactions reported herein may be relevant to the general problem of hydrodesulfurization (HDS) of thiophenic molecules.

Full text of DOI:10.1021/om970822d

5688
Organometallics 1997, 16, 5688-5695
Mod els for th e Hom ogen eou s Hyd r od esu lfu r iza tion of
Th iop h en es: Ma n ga n ese-Med ia ted Ca r bon -Su lfu r Bon d
Clea va ge a n d Hyd r ogen a tion Rea ction s
Conor A. Dullaghan, Gene B. Carpenter, and Dwight A. Sweigart*
Department of Chemistry, Brown University, Providence, Rhode Island 02912
Dai Seung Choi, Su Seong Lee, and Young K. Chung*
Department of Chemistry, Seoul National University, Seoul 151-742, Korea
Received September 18, 1997X
Chemical reduction of a series of (η5-thiophene)Mn(CO)3 complexes (3a -d ) under an
+
atmosphere of CO affords dimanganese metallathiacyclic complexes (4a -d ), which have a
Mn(CO)4 moiety regioselectively inserted into a C-S bond. Reaction of 4 with H2, the rate
of which is strongly influenced by substituents on the thiophene ring, leads to hydrogenolysis
of the Mn-C σ-bond and formation of (OC)3Mn(µ-H)(µ-SCRCHCHCHR′)Mn(CO)3 (8; R, R′
) H, Me), which contains bridging hydride and thiolate ligands and a Mn-Mn bond. The
addition of PhMgBr to 3 occurs at the sulfur to give zwitterionic complexes (6a -c, 14), which
undergo regioselective hydrogenolysis of a C-S bond and, in some cases, partial desulfur-
ization with concomitant formation of (OC)4Mn(µ-H)(µ-SPh)Mn(CO)4 (5a ). Crystal structures
are reported for complexes 4b,d , 5a , 8d , 10, 12c, and 14b,c. It is suggested that the reactions
reported herein may be relevant to the general problem of hydrodesulfurization (HDS) of
thiophenic molecules.
In tr od u ction
commonly, (3) generation of an electron-rich 16-electron
fragment that reacts directly with 1 by oxidative addi-
tion to a C-S bond to afford the generic metallathiacycle
2 (or analogous species).2,3
Due to the great importance of hydrodesulfurization
(HDS) in petroleum refining, a considerable amount of
research has been directed to the study of homogeneous
model systems that may mimic some of the chemical
steps occurring during the heterogeneously catalyzed
industrial process.1 Thiophenic molecules are of par-
ticular interest in this regard due to their reluctance to
undergo desulfurization, thus accounting for their rela-
tive abundance in fossil fuels. In the case of simple
thiophenes (1) (Chart 1), work has been directed at
activation of the heterocyclic ring to nucleophilic attack
as well as to C-S and C-H bond cleavage.2,3 The
strategies used to induce scission of a C-S bond in 1
include (1) coordination of a metal to the thiophene
π-system followed by nucleophilic attack at the ring,2a,3d,4
(2) coordination of a metal followed by reduction and
subsequent addition of an electrophile,3e,5 and, most
This paper is concerned with the use of manganese
to facilitate C-S bond scission in thiophenes. The Mn-
+
(CO)3 moiety is readily coordinated to thiophenes in
an η5-fashion as shown in structure 3.6 Nucleophiles
are known to react with 3 by adding to a ring carbon or
the sulfur atom without causing C-S bond cleavage. In
contrast to this behavior, chemical reduction of 3 leads
to C-S bond scission and formation of the bimetallic
(3) (a) Ogilvy, A. E.; Draganjac, M.; Rauchfuss, T. B.; Wilson, S. R.
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Organometallics 1997, 16, 1749.
S0276-7333(97)00822-4 CCC: $14.00 © 1997 American Chemical Society

Homogeneous Hydrodesulfurization of Thiophenes
Organometallics, Vol. 16, No. 26, 1997 5689
Ch a r t 1
Sch em e 1
4.7 In this paper various aspects of the transformation
3 f 4 are discussed. In addition, it is shown that the
reaction of 4 with H2 in certain cases results in hydro-
genolysis of the Mn-C σ-bond and formation of a
dimanganese complex (5) which contains bridging hy-
dride and thiolate ligands. Further, it is demonstrated
that 5a (R ) Ph) can also be obtained as one of the major
products of hydrogenation of 6, which is prepared by
addition of PhMgBr to 3. The bimetallic structural unit
Mn2(H)(SR) in 5 is of particular interest because of its
similarity to species suggested to occur with heteroge-
neous HDS catalysts.2c,8
Resu lts a n d Discu ssion
+
R ed u ct ion of (η5-Th iop h en e)Mn (CO)3 Com -
p lexes 3a -d . Cobaltocene reduction of 3a -d at room
temperature under an atmosphere of CO occurred
rapidly according to Scheme 1 to afford good yields of
the bimetallic 4, which contains a Mn(CO)4 moiety
inserted into a C-S bond. (The synthesis and X-ray
structure of 4a were previously communicated.7) The
X-ray structures of 4b,d were determined and found to
be virtually identical to that of 4a . Figure 1 shows the
structure of 4b, and Table 1 gives a summary of the
crystallographic data. The S1-C2-C3-C4-C5 dienyl
segment π-bonded to Mn(CO)3 is highly planar, with
mean deviations (Å) being: 4a , 0.030; 4b , 0.038; 4d ,
0.046. The Mn(CO)4 fragment is situated about 1.2 Å
above the dienyl plane, which is folded about the S1-
Mn2-C5 plane at the following angles (deg): 4a , 46.5;
4b, 45.3; 4d , 47.7. Complexes 4b,c were formed as
single isomers, indicating that 3 f 4 is a highly
regioselective process. It is noteworthy that Mn(CO)4
prefers to insert into an unsubstituted C-S bond, but
when there is no alternative, as in 3d , insertion to give
4d still takes place smoothly. In contrast to this,
Bianchini2l and Maitlis9 found that the nucleophiles
(triphos)Rh(H) and Pt(PEt3)3, respectively, insert cleanly
into the unsubstituted C-S bond in 2-methylthiophene
but are unreactive toward 2,5-dimethylthiophene. They
ascribe these great reactivity differences to steric con-
straints.
While the mechanism of formation of 4 by reduction
of 3 has yet to be established, it is clear that there must
be a transfer of a Mn(CO)n moiety from one thiophene
molecule to another. Such a transfer is known10 to occur
rapidly when (η6-naphthalene)Mn(CO)3+ is reduced with
1 equiv of cobaltocene and is believed to involve dis-
placement of naphthalene from the cationic complex by
the initially formed nucleophilic anion (η4-naphthalene)-
-
Mn(CO)3 to give a bimetallic complex, (η6,η4-naph-
thalene)Mn2(CO)5. The key mechanistic feature of this
reaction is the ease with which naphthalene can slip
(9) Garcia, J . J .; Arevalo, A.; Capella, S.; Chehata, A.; Hernandez,
M.; Montiel, V.; Picazo, G.; Del Rio, F.; Toscano, R. A.; Adams, H.;
Mailtis, P. M. Polyhedron 1997, 16, 385.
(10) (a) Sun, S.; Yeung, L. K.; Sweigart, D. A.; Lee, T.-Y.; Lee, S. S.;
Chung, Y. K.; Switzer, S. R.; Pike, R. D. Organometallics 1995, 14,
2613. (b) Sun, S.; Dullaghan, C. A.; Carpenter, G. B.; Rieger, A. L.;
Rieger, P. H.; Sweigart, D. A. Angew. Chem., Int. Ed. Engl. 1995, 34,
2540.
(7) Dullaghan, C. A.; Sun, S.; Carpenter, G. B.; Weldon, B.; Sweigart,
D. A. Angew. Chem., Int. Ed. Engl. 1996, 35, 212.
(8) (a) Bianchini, C.; J imenez, M. V.; Meli, A.; Moneti, S.; Patinec,
V.; Vizza, F. Angew. Chem., Int. Ed. Engl. 1996, 35, 1706. (b) Bianchini,
C.; Casares, J . A.; Meli, A.; Sernau, V.; Vizza, F.; Sanchez-Delgado, R.
A. Polyhedron 1997, 16, 3099.

5690 Organometallics, Vol. 16, No. 26, 1997
Dullaghan et al.
F igu r e 2. Crystal structure of 8d . Selected bond distances
(Å) and angles (deg) are Mn1-Mn2 2.817(1), Mn1-S1
2.303(1), Mn2-S1 2.317(1), Mn1-H1 1.665(39), Mn2-H2
1.628(38), Mn1-C2 2.159(4), Mn1-C3 2.205(4), Mn2-C4
2.256(4), Mn2-C5 2.307(4), S1-C2 1.756(4), C2-C3 1.378-
(5), C3-C4 1.467(5), C4-C5 1.373(5), C5-C6 1.503(6), C2-
C7 1.503(5); Mn1-S1-Mn2 75.16(4), Mn1-H1-Mn2 118-
(2), S1-Mn1-Mn2 52.65(3).
F igu r e 1. Crystal structure of 4b. Selected bond distances
(Å) and angles (deg) are Mn1-S1 2.364(2), Mn2-S1 2.334-
(2), Mn2-C5 2.046(5), Mn1-C2 2.164(4), Mn1-C3 2.156-
(4), Mn1-C4 2.163(4), Mn1-C5 2.395(5), S1-C2 1.746(5),
C2-C3 1.395(6), C3-C4 1.436(6), C4-C5 1.367(6), C2-
C6 1.489(6); S1-Mn2-C5 80.10(14), Mn2-S1-C2 110.7-
(2), S1-C2-C3 120.9(4), C2-C3-C4 124.4(4), C3-C4-C5
125.2(4), C4-C5-Mn2 127.8(4).
Sch em e 2
Ta ble 1. Cr ysta llogr a p h ic Da ta for Com p lexes 4b,d
4b
4d
formula
fw
C12H6Mn2O7S
404.11
C13H8Mn2O7S
418.13
temperature
wavelength, Å
cryst syst
space group
a, Å
298
298
0.71073
monoclinic
P21/c
9.244(2)
27.160(4)
12.289(2)
0.71073
triclinic
P1
8.4712(3)
9.1029(3)
12.4490(5)
70.367(1)
86.933(1)
63.062(1)
800.47(5)
2
b, Å
c, Å
R, deg
â, deg
104.099(14)
γ, deg
V, Å3
2992.4(9)
8
1.794
1.856
Z
d
calcd, g cm-3
1.735
1.737
416
µ, mm-1
different behavior is obtained with the manganese
metallathiacycle analog of benzothiophene.7) Reaction
of 4d with [Bu4N][BH4] in CH2Cl2 occurred cleanly to
afford a hydride addition product, tentatively assigned
structure 7 based on spectroscopic data.
F(000)
1600
cryst dimens, mm
θ range, deg
0.28 × 0.39 × 0.42
0.40 × 0.36 × 0.35
1.75-23.38
2960
1.87-25.00
no. of reflns collected 6601
no. of indept reflns
data/restraints/
parameters
5259 (Rint ) 0.0385) 2119 (Rint ) 0.0537)
5258/0/399
2119/0/208
Hyd r ogen a tion Rea ction s of Com p lex 4. The
unsubstituted complex 4a failed to react with H2 at 500
psi and 80 °C over 24 h. Increasing the temperature to
110 °C led to uncharacterized decomposition. In con-
trast, under the same experimental conditions (500 psi,
80 °C, 24 h), 4b converted in 61% yield to the bridging
hydride complex 8b, as shown in Scheme 1. Similarly,
hydrogenation of 4d gave 8d (81% yield) at tempera-
tures as low as 60 °C. The X-ray structure of 8d is
illustrated in Figure 2. The bridging diene thiolate
ligand is bonded to each manganese through the sulfur
and a carbon-carbon double bond. In the presence of
CO at 500 psi, 8d reacted as illustrated in Scheme 2;
complex 9 results from simple CO substitution for the
diene part of the thiolate ligand and was formed as a
1:1 mixture of cis:trans isomers. The formation of 10
is more complicated and features a hydride migration
to C4. The structure of 10 was verified by X-ray
diffraction (Figure 3, Table 2). The relative amounts
of 9 and 10 formed were found to depend markedly on
the temperature. Thus, the 9:10 ratio varied from 10:1
at 80 °C to 0.4:1 at 110 °C (see Experimental Section).
GOF on F2
0.875
1.109
final R indices
[I > 2σ(I)]
R indices (all data)
R1 ) 0.0454,
R2w )0.0987
R1 ) 0.0819,
R2w ) 0.1097
R1 ) 0.0401,
R2w )0.1096
R1 ) 0.0418,
R2w ) 0.1125
from η6- to η4-bonding. Application of the broad features
of this chemistry to the thiophene reactions presently
under consideration suggests as a plausible possibility
that initial electron transfer to 3 generates (η4-thiophene)-
Mn(CO)3-, which attacks and displaces the thiophene
from 3 to give a bimetallic intermediate that ultimately
transforms to 4. The known1d,11 ease with which
thiophenes can bind to a metal in an η4-fashion with a
concomitant increase in the nucleophilicity of the (non-
planar) sulfur atom lends credence to this possibility.
Complex 4d was found to be unreactive toward triflic
acid, from which one may conclude that the sulfur is
essentially nonbasic. This is not surprising since the
sulfur in 4d is, in effect, three-coordinate. (Quite
(11) Rauchfuss, T. B. Prog. Inorg. Chem. 1991, 39, 259.

Homogeneous Hydrodesulfurization of Thiophenes
Organometallics, Vol. 16, No. 26, 1997 5691
Ta ble 3. Isola ted Yield s of th e P r od u cts of
Hyd r ogen a tion Rea ction s of 6 a n d Rela ted
Com p lexes (Sch em e 3)
reaction conditions
(temp (°C),
pressure (psi),
isolated yields (%)
reactant solvent
time (h))
5a 11 12 13
6a
6b
6c
6a
6b
6c
6a
5a
CH2Cl2 45, H2 (700), 24
CH2Cl2 45, H2 (700), 24
CH2Cl2 45, H2 (700), 24
48 23
23
18 39
60
6
8
3
14
4
10
95
7
34
5
THF
THF
THF
25, H2 (700), 96
25, H2 (700), 96
25, H2 (700), 96
69
63
CH2Cl2 25, H2 (500), CO (250), 36
CH2Cl2 40, H2 (450), CO (150), 24
no reaction
F igu r e 3. Crystal structure of 10. Selected bond distances
(Å) and angles (deg) are Mn1-S1 2.352(2), Mn2-S1 2.441-
(2), Mn1-C2 2.097(5), Mn1-C3 2.118(5), Mn1-C4 2.174-
(5), S1-C2 1.781(6), C2-C3 1.401(8), C3-C4 1.392(7), C4-
C5 1.508(8), C5-C6 1.510(9), C2-C7 1.507(8); Mn1-S1-
Mn2 134.28(7), Mn1-S1-C2 59.1(2), C2-C3-C4 123.7(5),
C3-C2-C7 122.7(5), C3-C4-C5 120.3(5).
11a -c CH2Cl2 25, CO (450), 24
>90
11a
11c
CH2Cl2 40, H2 (600), 120
CH2Cl2 80, H2 (700), 48
8
21
19 25a
90
aAlso isolated from this reaction was a 16% yield of PhSSPh.
Catalytic HDS involves several essential steps: (1)
cleavage and eventual hydrogenolysis of the C-S bonds,
generally with concomitant hydrogenation of olefinic
bonds, (2) extraction of the sulfur from metal-containing
intermediates, and (3) recycling of the catalyst. With
thiophene analogs, a number of metal fragments are
known to insert into C-S (and/or C-H) bonds to give 2
or related species.1-3 The metals most commonly
utilized for this process are the heavier transition
metals: Ru, Rh, W, Ir, and Pt. Studies with bimetallic
systems2c,g,h,3c,e,g,j led to suggestions that C-S bond
cleavage (and desulfurization) is facilitated by the
presence of two metals, perhaps in analogy to the
industrial Mo/Co HDS catalyst. Reactions 3 + e- f 4,
4 + H2 f 8, and 8 + CO f 9 + 10 provide evidence
that electron transfer and availability of bimetallic sites
play a role in the ring opening as well as subsequent
hydrogenolysis and desulfurization of thiophene. Com-
plexes 8 and 9, which feature bridging hydride and
thiolate ligands, may be of general significance in this
regard. Thus, the Mn2(H)(SR) structural unit found in
8 and 9 is analogous to two others recently reported to
occur with heavier transition metal systems in model
HDS studies: RhW(H)(SR)8 and Ir2(H)(SR).3j Bimetallic
intermediates of this type may be present on the
heterogeneous HDS catalyst surfaces.2c,8
Hyd r ogen a tion a n d Rela ted Rea ction s of Com -
p lexes 6a -c. It was demonstrated6b,c previously that
a range of nucleophiles add to the thiophene ring in 3.
The site of attack is most often a carbon atom, but in
some cases nucleophilic addition occurs at the sulfur to
afford neutral zwitterionic complexes such as 6. In the
present work, the reaction of 6 with hydrogen was
examined. The results are summarized in Scheme 3
and tabulated in Table 3. Hydrogenations were per-
formed in two solventssCH2Cl2 and THF. In all cases,
regioselective hydrogenolysis of the S-C4 bond occurred
to give substantial amounts of 11 and 12. In addition,
in CH2Cl2, there was partial desulfurization to the
bridging hydride complex 5a as well as demetalation
to the alkyl phenyl sulfide 13. The bimetallic complex
5a contains the Mn2(H)(SR) structural unit and is very
similar to 8 and 9, which were obtained from hydroge-
nation of bimetallic 4. The structure of 5a was con-
firmed by X-ray diffraction (Figure 4, Table 4). Complex
5a proved to be unreactive toward a mixture of H2 and
CO over 24 h (Table 3) and probably constitutes a
thermodynamic sink in the chemistry depicted in Scheme
Ta ble 2. Cr ysta llogr a p h ic Da ta for Com p lexes 8d
a n d 10
8d
10
formula
fw
C12H10Mn2O6S
392.14
C14H10Mn2O8S
448.16
temperature
wavelength, Å
cryst syst
space group
a, Å
298
0.71073
298
0.71073
triclinic
P1
monoclinic
P21/c
14.1457(3)
6.7369(1)
31.9820(7)
9.1376(2)
13.1185(1)
16.8912(4)
81.093(1)
88.082(1)
69.679(1)
1875.41(6)
4
b, Å
c, Å
R, deg
â, deg
92.127(1)
γ, deg
V, Å3
3045.73(10)
8
1.794
1.815
Z
d
calcd, g cm-3
1.587
1.493
896
µ, mm-1
F(000)
1568
cryst dimens, mm
θ range, deg
0.10 × 0.24 × 0.34
0.15 × 0.26 × 0.28
1.22-23.29
7953
1.89-24.72
no. of reflns collected 10637
no. of indept reflns
data/restraints/
parameters
4951 (Rint ) 0.0449) 5144 (Rint ) 0.0393)
4951/0/387
5132/6/450
GOF on F2
1.121
1.162
final R indices
[I > 2σ(I)]
R indices (all data)
R1 ) 0.0442,
R2w ) 0.1086
R1 ) 0.0521,
R2w ) 0.1149
R1 ) 0.0496,
R2w ) 0.1095
R1 ) 0.0633,
R2w ) 0.1274
Exposure of pure samples of 9 and 10 to CO (acetone
solution, 500 psi, 100 °C) gave no reaction with the
former (3 h) and Mn2(CO)10 with the latter (12 h),
suggesting that 9 and 10 are formed via distinctly
separate pathways and do not interconvert.
The reaction of 4b or 4d with H2 results in hydro-
genolysis of the Mn-C4 bond and loss of a CO ligand.
Significantly, it was found that hydrogenation of 4d was
completely inhibited when the H2 contained 5% CO. One
interpretation of these results is that rate-limiting CO
dissociation from the Mn(CO)4 moiety occurs prior to
oxidative addition of H2 at this center, which is then
followed by reductive elimination of C4-H and rear-
rangement to the structure shown. The observed
reactivity of 4 with hydrogen follows the order 4d > 4b
>> 4a . It is likely that this order is due mainly to steric
constraints that are relaxed upon CO dissociation as 4
converts to 8.

5692 Organometallics, Vol. 16, No. 26, 1997
Dullaghan et al.
Sch em e 3
Ta ble 4. Cr ysta llogr a p h ic Da ta for Com p lexes 5a
a n d 12c
3. When 6a was reacted with H2 (500 psi) in the
presence of CO (250 psi), essentially complete conversion
to 12a took place. The η4-species 11 readily underwent
displacement of the sulfur ligand to give 12 when
treated with CO (450 psi) for 24 h. Similarly, the sulfur
in 11a was cleanly substituted by P(OEt)3 when reacted
at room temperature for 30 min. Under N2 in THF, 12
very slowly lost CO and reverted back to 11; the 12a f
11a conversion was more conveniently and rapidly
effected by reacting 12a with Me3NO. (Crystal structure
of 12c is shown in Figure 5.)
In order to further investigate the regioselectivity of
hydrogenolysis of the S-C bond, complexes 14b,c were
prepared (Chart 2). Both were characterized by an
X-ray crystal structure determination. The structure
of 14c is shown in Figure 6 (see also Table 5). Treat-
ment of 14 with H2 (600 psi) at 25 °C proceeded very
much as observed for 6 (Scheme 3). Thus, 5a was
formed, along with products analogous to 11-13. With
14c the S-C scission occurred at S-C4 to give 15, but
with 14b bond cleavage occurred predominantly at
S-C1 to yield 16. This suggests, as one might expect,
that the electronic effect of substituents at C2 and C3
can determine which S-C bond is broken.
5a
12c
formula
fw
C14H6Mn2O8S
444.13
C20H15MnO4S
406.32
temperature
wavelength, Å
cryst syst
space group
a, Å
298
0.71073
293
0.71073
monoclinic
P21/n
10.684(2)
10.789(2)
17.160(2)
monoclinic
P21/n
9.1614(2)
13.0295(1)
14.2989(2)
b, Å
c, Å
R, deg
â, deg
90.989(1)
103.336(14)
γ, deg
V, Å3
1706.58(5)
1924.7(6)
Z
d
4
4
calcd, g cm-3
1.729
1.640
880
1.402
0.815
832
µ, mm-1
F(000)
cryst dimens, mm
θ range, deg
0.25 × 0.38 × 0.40
0.40 × 0.35 × 0.30
2.25-24.93
2131
2.11-23.25
no. of reflns collected 6465
no. of indept reflns
data/restraints/
parameters
2353 (Rint ) 0.0400) 2024 (Rint ) 0.0353)
2353/0/230
2024/0/235
GOF on F2
0.986
1.120
final R indices
[I > 2σ(I)]
R indices (all data)
R1 ) 0.0314,
R2w ) 0.0772
R1 ) 0.0351,
R2w ) 0.0790
R1 ) 0.0486,
R2w ) 0.1177
R1 ) 0.0529,
R2w ) 0.1211
A plausible (partial) mechanism for the hydrogenation
of 6 is given in Scheme 4. In this mechanism, slippage
from η4- to η2-bonding of the thiophene ring permits
oxidative addition of H2. The zwitterionic nature of 6,
with the negative charge located on the metal, should
facilitate this process. Subsequent hydride migration
and S-C4 bond cleavage generate the allylic complex
11. Complexes 12 and 13 (Scheme 3) can easily be
envisioned to arise from further reactions of 11, as the
last two entries in Table 3 indicate.
Con clu sion s
+
In this study we report that coordination of Mn(CO)3
to the thiophene ring to give 3 results in activation of a
C-S bond to reductive cleavage, affording the bimetallic
4. Reaction of 4 with H2 results in hydrogenolysis of
the Mn-C σ-bond and opening of the thiophene ring to
afford a dimanganese species (8) containing bridging
F igu r e 4. Crystal structure of 5a . Selected bond distances
(Å) and angles (deg) are Mn1-Mn2 2.8939(5), Mn1-S1
2.3313(7), Mn2-S1 2.3276(7), Mn1-H1 1.789(27), Mn2-
H1 1.689(26), S1-C1 1.792(3); Mn1-S1-Mn2 76.80(2),
Mn1-H1-Mn2 117(1), S1-Mn1-Mn2 51.54(2).

Homogeneous Hydrodesulfurization of Thiophenes
Organometallics, Vol. 16, No. 26, 1997 5693
F igu r e 5. Crystal structure of 12c. Selected bond dis-
tances (Å) and angles (deg) are Mn-C7 2.183(5), Mn-C8
2.101(4), Mn-C9 2.250(5), S-C7 1.750(5), S-C1 1.767(5),
C7-C8 1.398(6), C8-C9 1.389(6), C9-C10 1.513(6), C10-
C11 1.519(6); S-C7-C8 120.4(4), C7-C8-C9 124.6(4),
C8-C9-C10 123.9(4).
F igu r e 6. Crystal structure of 14c. Selected bond dis-
tances (Å) and angles (deg) are Mn-C1 2.115(3), Mn-C2
2.112(3), Mn-C3 2.090(3), Mn-C4 2.110(4), C1-C2 1.443-
(4), C2-C3 1.402(4), C3-C4 1.429(5), S-C1 1.756(3), S-C4
1.756(4), S-C5 1.806(4), C2-C11 1.478(4); C1-S-C4 86.1-
(2), C5-S-C1 109.2(2), C5-S-C4 109.4(2), S-C1-C2
110.7(2), C1-C2-C3 109.0(3), C2-C3-C4 111.6(3), C3-
C4-S 110.0(2).
Ch a r t 2
Exp er im en ta l Section
Cr ysta l Str u ctu r e Deter m in a tion s. The crystal struc-
tures of 4b,d , 5a , 8d , 10, and 14b were determined with a
Siemens P4 diffractometer equipped with a CCD area detector
and controlled by SMART, version 4, software. (The structures
of 12c and 14c were determined with an Enraf-Nonius CAD4
diffractometer.) Data reduction was carried out by SAINT,
version 4, and included profile analysis; this was followed by
absorption correction by use of the program SADABS. Data
was collected at 25 °C with Mo KR radiation. The structures
were determined by direct methods and refined on F2 using
the SHELXTL, version 5, package. Hydrogen atoms were
introduced in ideal positions, riding on the carbon atom to
which they are bonded; each was refined with isotropic
temperature factors 20-50% greater than that of the ridden
atom. All other atoms were refined with anisotropic thermal
parameters. All of the crystals reported herein were grown
from pentane solutions.
Ta ble 5. Cr ysta llogr a p h ic Da ta for Com p lexes
14b,c
14b
14c
formula
fw
C14H11MnO3S
314.23
C19H13MnO3S
376.29
temperature
wavelength, Å
cryst syst
space group
a, Å
293
293
0.71073
triclinic
P1
0.71073
triclinic
P1
8.2710(14)
8.7630(6)
9.7890(6)
100.510(4)
92.419(13)
94.040(6)
694.76(13)
2
8.6656(6)
10.4706(9)
10.9134(8)
115.652(6)
95.117(6)
104.313(6)
842.81(11)
2
Syn th esis of [(η5-R1,R2,R3-th ioph en e)Mn (CO)3]BF4 (3a-
e). These complexes were prepared by a procedure previously
described for 3a ,d .6 In a typical synthesis, AgBF4 (1.1 mmol)
was added to Mn(CO)5Br (1.0 mmol) in CH2Cl2 (20 mL), and
the reaction mixture was stirred for 10 min at room temper-
ature in the absence of light. At this stage 1.5 mmol of the
thiophene of interest (1a -e) was added and the mixture
refluxed for 3 h. The volume was then reduced to 5 mL, and
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
Z
d
calcd, g cm-3
1.502
1.099
320
1.483
0.920
384
µ, mm-1
-
F(000)
the product precipitated as the BF4 salt by the addition of
cryst dimens, mm
θ range, deg
0.40 × 0.20 × 0.20
0.60 × 0.30 × 0.30
2.12-25.97
3171
Et2O. Reprecipitation from acetone with Et2O afforded pure
2.12-24.97
product as a bright yellow powder. For 3b: yield 63%. IR
no. of reflns collected 2617
(acetone): νCO ) 2072 (s), 2008 (s, br) cm-1
.
1H NMR (250
no. of indept reflns
data/restraints/
parameters
2431 (Rint ) 0.0100) 2956 (Rint ) 0.0081)
MHz, CD2Cl2): δ 7.05 (d, J ) 3.7 Hz, H4), 6.94 (t, J ) 3.4 Hz,
H3), 6.80 (d, J ) 2.9 Hz, H2), 2.67 (s, Me). Anal. Calcd for
C8H6O3Mn1S1B1F4: C, 29.66; H, 1.87. Found: C, 29.71; H,
1.88. For 3c: yield 68%. IR (acetone): νCO ) 2072 (s), 2014
2430/0/172
2954/0/217
GOF on F2
1.112
1.114
final R indices
[I > 2σ(I)]
R indices (all data)
R1 ) 0.0548,
R2w ) 0.1541
R1 ) 0.0687,
R2w ) 0.1671
R1 ) 0.0566,
R2w ) 0.1419
R1 ) 0.0689,
R2w ) 0.1535
(s), 2000 (s) cm-1 1H NMR (250 MHz, CD3C(O)CD3): δ 7.04
.
(br, 1H), 6.94 (br, 1H), 6.81 (br, 1H), 2.67 (s, Me). Anal. Calcd
for C8H6O3Mn1S1B1F4: C, 29.66; H, 1.87. Found: C, 29.38;
H, 1.80. For 3e: yield 82%. IR (CD2Cl2): νCO ) 2064 (s), 2010
(s) cm-1 1H NMR (250 MHz, CD3NO2): δ 7.72 (m, 2H, Ph),
.
hydride and thiolate ligands. In a complementary series
of reactions, the zwitterionic complex 6, formed via
nucleophilic addition of a phenyl group to the sulfur in
3, was found to undergo regioselective hydrogenolysis
of a C-S bond.
7.66 (m, 1H, Ph), 7.59 (m, 2H, Ph), 7.08 (s, H4), 6.90 (m, H2,3).
Anal. Calcd for C13H8O3Mn1S1B1F4: C, 40.43; H, 2.07; S, 8.31.
Found: C, 40.24; H, 1.91; S, 8.58.
Syn th esis of Com p lexes 4a -d . Cobaltocene (0.31 mmol)
and [3b-d ]BF4 (0.30 mmol) were combined in CH2Cl2, and the

5694 Organometallics, Vol. 16, No. 26, 1997
Dullaghan et al.
Sch em e 4
mixture was stirred at room temperature for 20 min under a
CO atmosphere. The solvent was removed in vacuo and the
product extracted with CH2Cl2. The CH2Cl2 solution was then
passed through neutral alumina (deactivated with 10% water)
with CH2Cl2 as eluant. After the solvent was removed under
vacuum, the resulting orange-yellow solid was washed with
MS: 392 (M+), 336 (M+ - 2CO), 308 (M+ - 3CO), 280 (M+
4CO). HR MS: M+ (m/z) calcd 391.8965, obsd 391.8960.
-
Rea ction of Com p lex 8d w ith CO. In a typical experi-
ment, 8d was dissolved in acetone (10 mL) and placed in the
bomb reactor, which was purged (×2) with CO (30 atm),
refilled with CO (30 atm), and placed in an oil bath at variable
temperatures for varying times. The bomb was immediately
cooled to room temperature and adjusted to atmospheric
pressure. The solution was concentrated in vacuo; separation
and purification of the products (9 and 10) was performed on
silica gel TLC with pentane as the eluant. The product ratio
9:10 depended on temperature and time in the following
manner: 10:1, 80 °C, 14 h; 5:3, 95 °C, 2 h; 2:5, 110 °C, 0.5 h.
The combined yield of 9 and 10 was in the range 70-75%.
For 9: obtained as a 1:1 mixture of cis and trans. IR
(hexanes): νCO ) 2098 (w), 2067 (s), 2014 (s), 2005 (s), 2000
(s), 1974 (s) cm-1. IR (CH2Cl2): νCO ) 2098 (w), 2068 (s), 2011
(vs), 2000 (s, br), 1969 (s, br) cm-1. (The IR spectra of the cis-
and trans-isomers are indistinguishable.) 1H NMR (250 MHz,
CD2Cl2): cis-isomer δ 6.94 (dd, J ) 14.4, 11 Hz, H3), 6.42 (d,
J ) 10.9 Hz, H2), 5.81 (m, J ) 14.4, 6.6 Hz, H4), 1.69 (d, J )
6.6 Hz, Me), 1.26 (s, Me), -16.07 (-H-); trans-isomer δ 6.83
(dd, J ) 15.9, 9.6 Hz, H3), 6.07 (d, J ) 15.9 Hz, H2), 5.62 (m,
H4), 2.29 (s, Me), 2.09 (d, J ) 10.6 Hz, Me), -16.14 (-H-). Anal.
Calcd for C14H10O8Mn2S1: C, 37.52; H, 2.25. Found: C, 37.41;
pentane and dried. For 4b: yield 65%. IR (hexanes) νCO
2080 (m), 2036 (vs), 1997 (s), 1991 (vs), 1975 (m), 1961 (vs)
cm-1 1H NMR (250 MHz, CD2Cl2): δ 6.74 (d, J ) 5.5 Hz, H2),
)
.
5.92 (dd, J ) 10, 5.5 Hz, H3), 5.00 (d, J ) 10.5 Hz, H4), 2.45
(s, Me). Anal. Calcd for C12H6O7Mn2S1: C, 35.67; H, 1.50.
Found: C, 35.81; H, 1.44. HR MS: M+ (m/z) calcd 403.8596,
obsd 403.8607. Spectral data for 4c: yield 72%. IR (hex-
anes): νCO ) 2079 (m), 2037 (vs), 1998 (s), 1991 (vs), 1977 (m),
1960 (vs) cm-1 1H NMR (250 MHz, CD2Cl2): δ 6.40 (s, H1),
.
6.26 (d, J ) 10 Hz, H3), 5.31 (d, J ) 10 Hz, H4), 2.28 (s, Me).
Anal. Calcd for C12H6O7Mn2S1: C, 35.67; H, 1.50. Found: C,
35.71; H, 1.46. MS FAB: 404 (M+), 348 (M+ - 2CO), 320 (M+
- 3CO), 292 (M+ - 4CO), 264 (M+ - 5CO). HR MS: M+ (m/
z) calcd 403.8596, obsd 403.8605. For 4d : yield 84%. IR
(hexanes): νCO ) 2079 (m), 2033 (vs), 1995 (s), 1991 (vs), 1969
(m), 1958 (vs) cm-1 1H NMR (250 MHz, CD3C(O)CD3): δ 7.05
.
(d, J ) 5.5 Hz, H2), 5.62 (d, J ) 5 Hz, H3), 2.52 (s, Me), 2.22
(s, Me). Anal. Calcd for C13H8O7Mn2S1: C, 37.34; H, 1.93.
Found: C, 37.30; H, 1.90. MS FAB: 418 (M+), 362 (M+
-
2CO), 334 (M+ - 3CO), 306 (M+ - 4CO). HR MS: M+ (m/z)
calcd 417.8753, obsd 417.8754.
H, 2.30. MS FAB: 448 (M+), 392 (M+ - 2CO), 336 (M+
-
4CO), 280 (M+ - 6CO). HR MS: M+ (m/z) calcd 447.8858,
obsd 447.8858 For 10, IR (hexanes): νCO ) 2115 (m), 2036 (vs),
Ad d ition of Hyd r id e to Com p lex 4d . Bu4NBH4 (0.06
mmol) was added to 4d (0.05 mmol) in CH2Cl2 (8 mL) at 0 °C
under N2. The reaction mixture was stirred for 20 min as the
temperature increased to ca. 25 °C. IR spectra at this point
indicated that there was a clean conversion to a single product.
The resulting orange solution was concentrated and chromato-
graphed through an alumina column with CH2Cl2 as the
eluant. Solvent removal afforded a thermally unstable product
assigned structure 7 based on NMR data. For 7: yield 87%.
IR (CH2Cl2): νCO ) 2079 (m), 1971 (vs), 1950 (br, s), 1894 (br,
2004 (vs), 1933 (s), 1918 (s) cm-1 1H NMR (250 MHz, CD2-
.
Cl2): δ 5.11 (d, J ) 9.8 Hz, H2), 2.51 (s, Me), 2.17 (m, -CH2-),
1.27 (t, J ) 7.4 Hz, Me), 1.10 (dt, J ) 9.7, 7.4 Hz, H3). Anal.
Calcd for C14H10O8Mn2S1: C, 37.52; H, 2.25. Found: C, 37.68;
H, 2.44. MS FAB: 448 (M+), 420 (M+ - CO), 364 (M+ - 3CO),
264 (M+ - 7CO). HR MS: M+ (m/z) calcd 447.8858, obsd
447.8839.
Syn th esis a n d Hyd r ogen a tion Rea ction s of Com p lexes
6a -c. The following typical procedure was used to synthesize
6. To a solution of 3 (0.40 mmol) in THF (10 mL), was added
PhMgBr (2.0 equiv) at 0 °C under N2. The reaction mixture
was stirred for 30 min and allowed to warm to room temper-
ature. To this solution were added diethyl ether (50 mL) and
water (30 mL). The organic layer was collected, dried over
MgSO4, concentrated, and chromatographed on a silica gel
column with n-hexane and diethyl ether (2:1) as eluant to give
the product as a yellow solid. Complex 6a was reported
previously.6b IR (acetone solution evaporated onto a NaCl
s), 1863 (m, sh) cm-1
.
1H NMR (250 MHz, CD3C(O)CD3): δ
4.90 (d, J ) 8.3 Hz, H3), 3.79 (dd, J ) 8.2, 4.4 Hz, H2), 3.44
(m, 8H, Bu), 3.28 (m, H1-exo), 2.48 (s, Me4), 1.88 (d, J ) 7.4
Hz, Me1), 1.80 (m, 8H, Bu), 1.42 (m, 8H, Bu), 0.97 (m, 12H,
Bu).
Hyd r ogen a tion of 4b,4d . The complex (0.1 mmol) was
dissolved in CH2Cl2 (10 mL) and placed in a Parr high-pressure
bomb reactor. The reactor was purged (×2) with H2, refilled
with H2 (500 psi), and placed in an oil bath at typically 90 °C
for 18 h (4b) or 4 h (4d ). The bomb was immediately cooled
to room temperature and adjusted to atmospheric pressure.
The solution was concentrated in vacuo, and purification was
performed on silica gel TLC with pentane as the eluant. The
products 8b,d were crystallized from a concentrated pentane
plate): νCO ) 1994 (s), 1885 (s) cm-1 1H NMR (CDCl3): δ 7.44
.
(m, 5H), 5.36 (s, 2H), 2.79 (s, 2H). Anal. Calcd for C13H9O3-
MnS1: C, 52.01; H, 3.02; S, 10.66. Found: C, 52.13; H, 3.11;
S, 10.65. For 6b: yield 45%. IR (NaCl): νCO ) 1987 (s), 1885
(s) cm-1
.
1H NMR (CDCl3): δ 7.5-7.2 (m, 5H), 5.32 (t, J )
solution at -20 °C. For 8b: yield 61%. IR (hexanes): ν(CO)
)
.
2.8 Hz, H2), 4.98 (dd, J ) 1.2, 2.7 Hz, H3), 2.65 (dd, J ) 1.0,
2.7 Hz, H1), 1.73 (s, Me). HR MS: M+ (m/z) calcd 313.9809,
obsd 313.9750. For 6c: yield 34%. IR (CDCl3): νCO ) 2000
2054 (s), 2022 (s), 1983 (s), 1969 (s), 1956 (s), 1950 (s) cm-1
1H NMR (250 MHz, CD2Cl2): δ 4.91 (m, H2), 3.94 (dd, J ) 12,
8 Hz, H3), 2.27 (d, J ) 8 Hz, H4), 2.21 (s, Me), 1.76 (d, J ) 13
Hz, H4′), -14.51 (s, -H-). For 8d : yield 81%. IR (hexanes):
ν(CO) ) 2051 (s), 2019 (s), 1979 (s), 1964 (s), 1951 (s), 1948 (s)
(s), 1912 (s), 1889 (s) cm-1 1H NMR (CDCl3): δ 7.4-7.1 (m,
.
2Ph), 5.72 (dd, J ) 1.2, 2.9 Hz, H3), 5.42 (t, J ) 2.9 Hz, H2),
2.94 (dd, J ) 1.2, 2.7 Hz, H1). Anal. Calcd for C19H13O3-
MnS1: C, 60.64; H, 3.46; S, 8.53. Found: C, 60.69; H, 3.65; S,
8.88.
Hydrogenation reactions of 6a -c were performed in THF
at room temperature and in CH2Cl2 at various temperatures.
cm-1 1H NMR (250 MHz, CD2Cl2): δ 4.73 (s, H2), 3.84 (d, J
.
) 12 Hz, H3), 2.64 (m, J ) 12, 6 Hz, H4), 2.20 (s, Me), 1.50 (d,
J ) 6 Hz, Me), -14.48 (s, -H-). Anal. Calcd for C12H10O6-
Mn2S1: C, 36.75; H, 2.57. Found: C, 36.68; H, 2.60. FAB

Homogeneous Hydrodesulfurization of Thiophenes
Organometallics, Vol. 16, No. 26, 1997 5695
A steel pressure bomb was used, and the total pressure of H2
was in the range 600-750 psi. A typical procedure was as
follows: complex 6a -c (0.80 mmol) in THF (10 mL) was placed
in a 100-mL volume bomb reactor. The reactor was purged
with N2 for 10 min and then pressurized with H2 to 700 psi.
The reaction was stirred for 4 days at room temperature. After
releasing the H2, the solution was filtered and concentrated.
Product separation and purification was achieved using pre-
parative silica gel TLC with Et2O:hexanes (1:10) as eluant or
silica gel flash column chromatography with hexane as eluant.
Analogous experiments were also performed wth CH2Cl2 as
the solvent. In these cases, the solvent was stripped after
reaction and the resultant mixture chromatographed on a
silica gel column. The phenyl alkyl sulfide (13) shown in
Scheme 2 as well as PhSSPh (Table 3) were isolated and
Hz, H1), 2.14 (m, -CH2), 1.98 (m, -CH2), 1.17 (t, J ) 7.40 Hz,
Me). 13C NMR (125 MHz, CDCl3): δ 15.93, 27.36, 46.67, 72.07,
99.39, 125.60, 126.34, 128.88, 141.30. Anal. Calcd for
C
15H13O4Mn1S1: C, 52.33; H, 3.81. Found: C, 52.40; H, 3.83.
HR MS: M+ (m/z) calcd 343.9911, obsd 343.9907. For 12c,
IR (hexanes): νCO ) 2050 (w), 2000 (s), 1976 (vs), 1962 (vs)
cm-1 1H NMR (250 MHz, CDCl3): δ 7.17-7.37 (m, Ph, Ph),
.
4.92 (t, J ) 10 Hz, H2), 3.46 (dd, J ) 14.0, 3.0 Hz, H3), 3.18
(m, -CH2), 3.04 (d, J ) 9.4 Hz, H1). 13C NMR (125 MHz,
CDCl3): δ 40.05, 47.64, 67.90, 100.02, 125.70, 126.40, 126.87,
128.49, 128.82, 128.93, 140.03, 140.97. Anal. Calcd for
C
20H115O4Mn1S1: C, 59.11; H, 3.72; S, 7.89. Found: C, 58.66;
H, 3.51; S, 7.62. HR MS: M+ (m/z) calcd 378.0118, obsd
378.0117. For 13a , 1H NMR (CDCl3): δ 7.3-7.1 (m, Ph), 2.92
(t, J ) 7.4 Hz, H1), 1.63 (m, H2), 1.45 (m, H3), 0.92 (t, J ) 7.4
Hz, Me). HR MS: M+ (m/z) calcd 166.0816, obsd 166.0824.
Rea ction of Com p lex 11a w ith P (OEt)3. P(OEt)3 (0.1
mL, 0.66 mmol) and 11a (0.10 g, 0.33 mmol) were dissolved
in CH2Cl2 (15 mL). The reaction mixture was stirred for 30
min at room temperature, after which the solution was
concentrated and chromatographed on silica gel with hexane
as the eluant. The solvent was removed in vacuo, and the
product, which contains a P(OEt)3 group substituted for the
thioether ligand, was obtained in quantitative yield. IR
1
identified by H NMR and MS. The organometallic products
11a -c were obtained as a roughly 1:1 mixture of diastereo-
mers (A + B) resulting from exo- and endo-orientations of the
phenyl group on the chiral sulfur atom.
For 5a , IR (hexanes): νCO ) 2100 (w), 2070 (m), 2020 (vs),
2004 (s), 1974 (s, br) cm-1. IR (CH2Cl2): νCO ) 2102 (w), 2072
(s), 2019 (vs), 2002 (s), 1971 (s, br) cm-1 1H NMR (CDCl3): δ
.
7.57 (m, 2H, Ph), 7.23 (m, 3H, Ph), -15.97 (s, -H-). Anal. Calcd
for C14H6O8Mn2S1: C, 37.86; H, 1.36; S, 7.22. Found: C, 38.18;
H, 1.35; S, 7.26. For 11a : A + B isomers. IR (hexanes): νCO
(hexanes): νCO ) 2010 (s), 1944 (vs), 1924 (vs) cm-1 1H NMR
.
) 2016 (s), 1938 (vs), 1927 (vs) cm-1
.
1H NMR (250 MHz,
(250 MHz, CDCl3): δ 7.38 (m, Ph), 7.28 (m, Ph), 7.08 (m, Ph),
4.85 (dd, J ) 11.2, 8.9 Hz, H2), 4.06 (m, P-OCH2-), 2.90 (m,
H3), 2.59 (dd, J ) 14.6, 8.9 Hz, H1), 1.71 (d, J ) 6.1 Hz, Me),
1.29 (t, J ) 7.0, P-OCH2Me). Anal. Calcd for C19H26O6P1-
Mn1S1: C, 48.92; H, 5.60. Found: C, 48.90; H, 5.67. HR MS:
M+ (m/z) calcd 468.0560, obsd 468.0576.
CDCl3): A isomer δ 7.0-7.25 (m, 5H, Ph), 5.23 (m, H1,2), 1.67
(d, J ) 6.3 Hz, Me), 1.50 (m, H3); B isomer δ 7.26-7.45 (m,
Ph), 5.47 (dd, J ) 3.8, 1.0 Hz, H1), 5.04 (dd, J ) 9.5, 3.8 Hz,
H2), 1.72 (d, J ) 5.9 Hz, Me), 1.32 (m, H3). 13C NMR (125
MHz, CDCl3): δ 18.50, 18.98, 54.03, 57.76, 66.17, 69.42, 91.47,
101.11, 128.82, 129.11, 129.37, 129.62, 129.81, 130.24, 141.30.
Anal. Calcd for C13H11O3Mn1S1: C, 51.66; H, 3.67; S, 10.6.
Found: C, 51.44; H, 3.74; S, 10.9. HR MS: M+ (m/z) calcd
301.9816, obsd 301.9818. For 11b: A + B isomers. IR
Syn th esis a n d Rea ction s of 14b,c. These complexes were
synthesized by the same procedure used for the synthesis of
6a -c. For 14b: yield 46%. IR (hexanes): νCO ) 1998, 1918,
1911 cm-1 1H NMR (250 MHz, CDCl3): δ 7.40 (m, Ph), 7.30
.
(hexanes): νCO ) 2015 (s), 1939 (vs), 1927 (vs) cm-1
.
1H NMR
(m, Ph), 5.18 (s), 2.74 (d, J ) 2.1 Hz), 2.62 (t, J ) 2.7 Hz).
Anal. Calcd for C14H11O3Mn1S1: C, 53.51; H, 3.53. Found:
(250 MHz, CDCl3): A isomer δ 7.0-7.27 (m, Ph), 5.24 (m,
H1,2), 1.97 (m, CH2), 1.47 (dt, J ) 9.5, 6.7 Hz, H3), 0.97 (t, J
) 7.4 Hz, Me); B isomer δ 7.20-7.45 (m, Ph), 5.50 (d, J ) 4.0
Hz, H1), 5.04 (dd, J ) 9.5, 4.0 Hz, H2), 1.97 (m, CH2), 1.30
(dt, J ) 9.5, 6.7 Hz, H3), 1.18 (t, J ) 7.4 Hz, Me). 13C NMR
(125 MHz, CDCl3): δ 16.93, 17.23, 27.13, 27.26, 54.22, 66.60,
69.78, 75.17, 90.22, 99.64, 124.81, 129.02, 129.40, 129.66,
129.97, 130.35, 141.30. Anal. Calcd for C14H13O3Mn1S1: C,
53.17; H, 4.14. Found: C, 53.30; H, 4.15. HR MS: M+ (m/z)
calcd 315.9962, obsd 315.9963. For 11c: A + B isomers. IR
C, 53.60; H, 3.50. For 14c: yield 44%. IR (CH2Cl2): νCO
)
1989, 1907, 1898 cm-1 1H NMR (250 MHz, CDCl3): δ 7.50
.
(m, Ph), 7.35 (m, Ph), 5.76 (dd, J ) 2.7, 1.4 Hz), 3.24 (dd, J )
2.9, 1.4 Hz), 2.85 (t, J ) 2.9 Hz). Anal. Calcd for C14H11O3-
Mn1S1: C, 60.64; H, 3.46; S, 8.53. Found: C, 60.48; H, 3.41;
S, 8.86. For 15: yield 32%. IR (hexanes): νCO ) 2060 (w),
2005 (s), 1972 (s), 1957 (vs) cm-1
.
1H NMR (250 MHz,
CDCl3): δ 7.6-7.2 (m, 10H, Ph), 4.93 (d, J ) 10.3 Hz, 1H),
3.96 (d, J ) 10.3 Hz, 1H), 2.30 (s, Me). For 16: yield 57%. IR
(hexanes): νCO ) 2005 (s), 1939 (vs), 1926 (vs) cm-1
.
1H NMR
(hexanes): νCO ) 2010, 1933, 1920 cm-1 1H NMR (250 MHz,
.
(250 MHz, CDCl3): A isomer δ 6.8-7.40 (m, Ph, Ph), 5.30 (m,
H1,2), 3.38 (m, CH2), 1.68 (m, H3); B isomer δ 7.10-7.40 (m,
Ph, Ph), 5.53 (dd, J ) 4.1, 1.2 Hz, H1), 5.17 (dd, J ) 9.4, 4.1
Hz, H2), 3.08 (m, CH2), 1.44 (m, H3). 13C NMR (125 MHz,
CDCl3): δ 39.39, 39.82, 55.03, 63.03, 70.50, 71.11, 90.65,
100.36, 124.93, 125.91, 126.19, 127.64, 128.11, 128.24, 128.55,
128.90, 129.14, 129.44, 129.75, 129.94, 130.21, 130.41, 142.29,
142.56. Anal. Calcd for C19H15O3Mn1S1: C, 60.32; H, 4.00.
Found: C, 60.60; H, 4.00. HR MS: M+ (m/z) calcd 378.0118,
obsd 378.0122.
CDCl3): one diastereomer δ 7.3-7.0 (m, Ph), 5.11 (s, 1H), 2.03
(s, Me), 1.61 (d, J ) 6.1 Hz, Me), 1.36 (m, 1H); other
diastereomer δ 7.6-7.3 (m, Ph), 5.29 (s, 1H), 2.06 (s, Me), 1.69
(d, J ) 6.1 Hz, Me), 1.11 (m, 1H). Anal. Calcd for C14H13O3-
Mn1S1: C, 53.17; H, 4.14. Found: C, 52.51; H, 3.87.
Ack n ow led gm en t. This work was supported by
grants from the National Science Foundation (CHE-
9400800, CHE-9705121, and INT-9312709), the Petro-
leum Research Fund, administered by the American
Chemical Society, the Korea Science and Engineering
Foundation (KOSEF, 96-0501-03-01-3), and the Korean
Ministry of Education (BSRI 96-3415).
For 12a , IR (hexanes): νCO ) 2052 (w), 1999 (s), 1976 (vs),
1960 (vs) cm-1 1H NMR (250 MHz, CDCl3): δ 7.15-7.38 (m,
.
Ph), 4.90 (dd, J ) 11.4, 9.5 Hz, H2), 3.08 (dq, J ) 11.4, 6.0 Hz,
H3), 2.96 (d, J ) 9.5 Hz, H1), 1.80 (d, J ) 6.0 Hz, Me). 13C
NMR (125 MHz, CDCl3): δ 19.65, 46.78, 63.59, 101.44, 125.62,
126.38, 128.86, 141.30. Anal. Calcd for C14H11O4Mn1S1: C,
50.92; H, 3.36. Found: C, 51.20; H, 3.36. HR MS: M+ (m/z)
Su p p or tin g In for m a tion Ava ila ble: Tables of atomic
coordinates, bond lengths and angles, anisotropic displacement
parameters, and hydrogen coordinates for 4b,d , 5a , 8d , 10,
12c, and 14b,c (97 pages). Ordering information is given on
any current masthead page.
calcd 301.9806, obsd 301.9812. For 12b, IR (hexanes): νCO
)
2052 (w), 1999 (s), 1977 (vs), 1966 (vs) cm-1 1H NMR (250
.
MHz, CDCl3): δ 7.17-7.35 (m, Ph, Ph), 4.88 (dd, J ) 11.9, 9.4
Hz, H2), 3.08 (ddd, J ) 11.9, 7.2, 5.0 Hz, H3), 2.96 (d, J ) 9.4
OM970822D