Addition of benzenethiol to terminal alkynes catalyzed by hydrotris(3,5-dimethylpyrazolyl)borate-Rh(III) bis(thiolate) complex: Mechanistic studies with characterization of the key intermediate

Article abstract of DOI:10.1016/j.jorganchem.2006.03.005

The Rh(III)-thiolate complex [Tp^*Rh(SPh)₂(MeCN)] (2; Tp^* = hydrotris(3,5-dimethylpyrazolyl)borate) readily undergoes substitution of MeCN by XyNC (Xy = 2,6-dimethylphenyl) to give the isocyanide complex [Tp^*Rh(S

Full text of DOI:10.1016/j.jorganchem.2006.03.005

Journal of Organometallic Chemistry 691 (2006) 3157–3164
www.elsevier.com/locate/jorganchem
Addition of benzenethiol to terminal alkynes catalyzed by
hydrotris(3,5-dimethylpyrazolyl)borate–Rh(III) bis(thiolate) complex:
Mechanistic studies with characterization of the key intermediate
*
Yoshiyuki Misumi, Hidetake Seino, Yasushi Mizobe
Institute of Industrial Science, the University of Tokyo, Tokyo, Japan
Received 4 January 2006; accepted 2 March 2006
Available online 9 March 2006
Abstract
The Rh(III)–thiolate complex [Tp*Rh(SPh)2(MeCN)] (2; Tp* = hydrotris(3,5-dimethylpyrazolyl)borate) readily undergoes substitu-
tion of MeCN by XyNC (Xy = 2,6-dimethylphenyl) to give the isocyanide complex [Tp*Rh(SPh)2(XyNC)] (3), whereas reaction of 2
with terminal alkynes results in the formation of the rhodathiacyclobutene complex [Tp*Rh(SPh){g2-CH@CR(SPh)}] (4; R = aryl,
alkyl). Molecular structures of 3 and 4 (R = CH2Ph) have been determined by single crystal X-ray diffraction. Complex 2 as well as
[Tp*Rh(cyclooctene)(MeCN)] have been found to catalyze regioselective addition of benzenethiol to terminal alkynes RC„CH at
50 ꢀC to give R(PhS)C@CH2 in moderate to high yields. The above products are selectively formed when R = CH2Ph and n-C6H13, while
cis-RCH@CHSPh and RC(SPh)2CH3 are also obtained as by-products when R = p-MeOC6H4. Catalytic cycle involving 2 and 4 is pro-
posed based on the mechanistic studies using NMR measurement.
ꢁ 2006 Elsevier B.V. All rights reserved.
Keywords: Hydrotris(pyrazolyl)borate; Rhodium(III) thiolato complexes; Rhodathiacyclobutene; Hydrothiolation of alkyne
1. Introduction
route to synthesize rhodium thiolate complexes with Tp
ancillary ligands and their chalcogenolate congeners
[20,21]. The Rh(I) complex [TpRh(coe)(MeCN)] (coe =
g2-cyclooctene) and its hydrotris(3,5-dimethylpyrazolyl)-
borate (Tp*) analog [Tp*Rh(coe)(MeCN)] (1) [22] react with
a range of organic disulfides to give mononuclear bis(thio-
late) complexes, as exemplified in Eq. (1). Further conver-
sion to dinuclear complexes bridged by l-thiolate ligands
has been also achieved. Here, we discuss the reactivities of
bis(thiolate) complex 2 toward organic molecules and its
application to catalytic C–S bond formation.
Thiolate ligands are not only good electron-donors but
also effective bridging ligands between two or more metal
atoms to form multinuclear complexes [1–7]. Due to high
affinity of sulfur atoms with transition metals, thiolate
ligands in transition metal catalysts usually play an impor-
tant role to maintain the coordination sphere around the
metal center or multimetallic core [8–13]. On the other
hand, thiolate complexes often become the key intermedi-
ates in metal-aided C–S bond forming reactions that pro-
ceed stoichiometrically [14,15] and catalytically [16–19].
In contrast to the rich chemistry of thiolate complexes
containing cyclopentadienyl ligands, that of the hydro-
tris(pyrazolyl) borate (Tp) analogs is much less explored
especially for noble metals, due to low accessibility to start-
ing materials. We have recently reported the first reliable
HB
N
N
HB
N
N
N
N
N
ArSSAr
N
N
N
Rh
(1)
N
Rh SAr
SAr
N
THF, 20 ˚C, 40 h
N
N
C
C
Me
Me
*
1
Corresponding author. Fax: +81 3 5452 6362.
E-mail address: ymizobe@iis.u-tokyo.ac.jp (Y. Mizobe).
2: Ar = Ph
2': Ar = C6H4Me-
p
0022-328X/$ - see front matter ꢁ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.03.005

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Y. Misumi et al. / Journal of Organometallic Chemistry 691 (2006) 3157–3164
Table 1
2. Results and discussion
Selected bonding parameters in 3
˚
Bond lengths (A)
2.1. Reactivities of [Tp*Rh(SPh)2(MeCN)] toward
organic molecules
Rh–S(1)
2.3574(6)
2.124(2)
2.132(2)
1.776(2)
1.149(3)
Rh–S(2)
Rh–N(4)
Rh–C(28)
S(2)–C(22)
N(7)–C(29)
2.3534(5)
2.138(2)
1.902(2)
1.775(2)
1.397(3)
Rh–N(2)
Rh–N(6)
S(1)–C(16)
N(7)–C(28)
The bis(thiolate) complex [Tp*Rh(SPh)2(MeCN)] (2)
[20] was treated with several organic molecules to examine
the reactivity at the metal center. When 2 was treated with
excess XyNC at room temperature, the MeCN ligand
Bond angles (ꢀ)
S(1)–Rh–S(2)
91.80(2)
90.25(7)
84.96(6)
177.1(2)
S(1)–Rh–N(2)
S(2)–Rh–N(4)
N(6)–Rh–C(28)
C(28)–N(7)–C(29)
173.88(4)
S(1)–Rh–C(28)
S(2)–Rh–C(28)
Rh–C(28)–N(7)
177.93(5)
177.51(9)
174.2(2)
in
2 was smoothly replaced by XyNC to form
[Tp*Rh(SPh)2(XyNC)] (3). Complex 3 has been character-
ized by spectroscopic methods and unambiguously by X-
ray diffraction study as shown in Fig. 1 and Table 1. The
Rh center of 3 adopts a slightly distorted octahedral geom-
etry as observed for 2, whose structure has been previously
confirmed by the X-ray analysis of the p-toluenethiolate
analog [Tp*Rh(SC6H4Me-p)2(MeCN)] (20) [20]. Three
Rh–N bond distances in 3 are almost the same, indicating
that the trans influence of XyNC ligand is comparable to
that of benzenethiolate. The Rh–N bond at the trans posi-
determined by X-ray crystallography, as shown in Fig. 2
and Table 2. The planar 4-membered ring consists of the
Rh–S and alkyne moiety, with terminal C atom bound to
Rh. The Rh–C(28) and the C(28)–C(29) distances are typ-
ical of the Rh–C single and C–C double bonds, respec-
tively. Hydrogen atom attached to C(28) have been
found in difference Fourrier map, and sum of the bond
angles around C(28) at 359ꢀ as well as that around C(29)
at 360ꢀ indicate planar geometry of the rhodathiacyclobu-
tene moiety. Two Rh–S distances are almost comparable,
while trans influence of thioether unit is weaker than that
of thiolate ligand as reflected in the Rh–N(2) and Rh–
˚
tion of XyNC in 3 at 2.132(2) A is much longer than that
0
˚
trans to MeCN at 2.056(3) A in 2 , while the other corre-
sponding Rh–S and Rh–N distances are not significantly
different between 3 and 20. Linear structure of the Rh–C–
N–Xy linkage and the C„N stretching frequency are in
good agreement with those of [Tp*Rh(g2-S5)(XyNC)]
(mN„C at 2187 cmꢀ1) [23].
Although 2 showed no reactivity toward alkenes, it
smoothly reacted with various terminal alkynes RC„CH
(R = alkyl, aryl) at ambient temperature to yield
the rhodathiacyclobutene complexes [Tp*Rh(SPh){g2-
CH@CR(SPh)}] (4) (Eq. (2)). Thermal instability (vide
infra) and high solubility in common organic solvents pre-
vented isolation of most of 4 except for 4a (R = CH2Ph)
and 4b (R = Ph). The molecular structure of 4a was fully
˚
N(4) distances at 2.076(3) and 2.159(4) A, respectively.
Configuration of the phenyl group bound to S(1) is anti
to the thiolate ligand (I in Eq. (3)). Distorted structure of
the rhodathiacyclobutene ring is quite similar to the
4-membered ring in [Tp*Rh(g2-S-2-C5H4N)(g1-S-2-
C5H4N)] [20].
N(5)
B
N(1)
N(2)
N(6)
Rh
N(3)
S(2)
N(4)
S(1)
C(28)
N(7)
C(29)
Fig. 2. Molecular structure of 4a. Hydrogen atoms except for H(33) are
Fig. 1. Molecular structure of 3. Hydrogen atoms are omitted for clarity.
omitted for clarity.

Y. Misumi et al. / Journal of Organometallic Chemistry 691 (2006) 3157–3164
3159
Table 2
of 1, reactions of 3-phenylpropyne or 1-octyne with equimo-
lar amount of PhSH proceeded regioselectively at 50 ꢀC to
afford the Markovnikov products, which were isolated in
92% or 58% yields, respectively (Eq. (4)). However, 1 was
not so effective for the reaction of p-MeOC6H4C„CH with
PhSH. On the other hand, 2 could catalyze even the hydro-
thiolation of p-MeOC6H4C„CH, although larger amount
of catalyst (10 mol%) and longer reaction time were neces-
sary for completion and concomitant formations of the reg-
ioisomer cis-p-MeOC6H4CH@CHSPh and the thioketal
p-MeOC6H4C(SPh)2CH3 were observed (Eq. (5)).
Selected bonding parameters in 4a
˚
Bond lengths (A)
Rh–S(1)
Rh–N(2)
Rh–N(6)
S(1)–C(16)
S(2)–C(22)
C(29)–C(30)
2.341(1)
2.076(3)
2.150(3)
1.789(6)
1.775(5)
1.504(7)
Rh–S(2)
Rh–N(4)
Rh–C(28)
S(1)–C(29)
C(28)–C(29)
C(28)–H(33)
2.345(2)
2.159(4)
1.994(4)
1.819(4)
1.326(6)
0.86(3)
Bond angles (ꢀ)
S(1)–Rh–S(2)
81.77(5)
69.5(1)
86.2(2)
115.4(1)
106.9(2)
130(2)
103.5(3)
136.6(4)
S(1)–Rh–N(2)
S(2)–Rh–N(4)
168.0(1)
S(1)–Rh–C(28)
S(2)–Rh–C(28)
Rh–S(1)–C(16)
C(16)–S(1)–C(29)
Rh–C(28)–H(33)
S(1)–C(29)–C(28)
C(28)–C(29)–C(30)
174.99(8)
168.3(1)
79.8(1)
107.0(3)
122(2)
N(6)–Rh–C(28)
Rh–S(1)–C(29)
Rh–C(28)–C(29)
C(29)–C(28)–H(33)
S(1)–C(29)–C(30)
PhS
THF, 50 ˚C, 7 h
(4)
PhSH
+ R
1 (5 mol%)
R
119.9(3)
R = CH Ph: 92% yield
2
R = n-C H : 58% yield
6 13
HB
N
N
N
RC CH
THF, 0—20 ˚C, 4 h
N
N
(2)
2
N
Rh SPh
S
Ph
THF, 50 ˚C, 9 h
PhSH
MeO
+
2 (10 mol%)
R
4a: R = CH2Ph
4b: R = Ph
SPh
PhS
PhS
SPh
In contrast to the crystal structure of 4a, each 1H NMR
(5)
+
+
spectrum of 4 indicates the existence of two species in solu-
tion. Chemical shifts of hydrogen atom directly attached to
the rhodathiacyclobutene ring of both species are close,
and they are coupled with Rh atom of comparable cou-
pling constants. Three pyrazolyl moieties in each species
are inequivalently observed as expected. Therefore, it is
concluded that those species differ in configuration with
respect to the phenyl group bound to the metallacycle
and are in equilibrium in solution (Eq. (3)).
MeO
MeO
MeO
18% yield
(based on alkyne)
63% yield (3 : 1 mixture)
Vinyl thioethers are significant intermediates for synthe-
sizing important organosulfur compounds, and metal-cata-
lyzed hydrothiolation of non-activated alkynes leading to
them has been precedented. Some noble metal complexes
have been reported to be active, whose product selectivities
are compared as follows by referring the reaction of 1-octyne
and PhSH as representative (Eq. (6)). Thus, reactions using
Pd(CH3CO2)2 [24] or combination of [Ni(PMePh2)4] and
Ph2P(O)OH [25] are known to afford the isomer A, similarly
to our result. In contrast, migration of double bond leading
to B occurs in the catalysis by [PdCl2(PhCN)2] or [Pt(PPh3)4],
while the use of [RhCl(PPh3)3] in EtOH has been found to
provide the regioisomer trans-C [24,26].
HB
HB
N
N
N
N
N
N
N
N
N
N
N
N
(3)
Rh SPh
S
Rh SPh
S
Ph
Ph
R
R
I
II
2.2. Catalytic addition of benzenethiol to terminal alkynes
Complex 4 was found to be unstable even at room temper-
ature. Its decomposition formed uncharacterized Rh species
and R(PhS)C@CH2. Since these vinyl thioethers are pre-
sumed to be generated by protonation of g2-CH@CR(SPh)
ligands, addition reactions of PhSH to RC„CH have been
examined, and it has been found that 2 as well as 1 promote
these reactions catalytically. Thus, in the presence of 5 mol%
PhSH
+
n
-C H
6 13
SPh
PhS
PhS
(6)
+
+
n
-C H
6
n
-C H
5
n-C H
6 13
13
11
A
B
C

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Y. Misumi et al. / Journal of Organometallic Chemistry 691 (2006) 3157–3164
no reactivity toward terminal alkynes at ambient tempera-
ture. These findings indicate that the active species is also 2
in the reaction using 1 as the catalyst precursor, if 1 initially
reacts with PhSH. It is to be noted that several Tp–Rh(I)
complexes having alkene ligands are reported to catalyze
polymerization of arylacetylenes but not to interact with
alkylacetylenes [30]. In addition, [Tp*Rh(PR3)2] (R = Ph,
C6H4F-p) has been known to react with phenylacetylene to
give [Tp*RhH(C„CPh)(PR3)] [31]. Therefore, the reactivity
of arylacetylenes toward 1 is estimated to be higher than that
of less acidic alkylacetylenes, and the substantial reaction
with alkyne prior to PhSH may result in less effectiveness
of 1 than 2 as observed in the reaction with p-
MeOC6H4C„CH.
Several Rh(I) and Ir(I) complexes having bidentate N-
donor co-ligands have also been shown to promote
hydrothiolation [27]. Very recently, Love and coworkers
have reported that [Tp*Rh(PPh3)2] (5) is an active cata-
lyst, especially for addition of alkanethiols [28]. Most
reactions of R0SH and RC„CH using 5 provide the
branched isomer R(R0S)C@CH2 exclusively, exhibiting
the regioselectivity similar to the systems using 1 and 2,
while 5 considerably causes migration of double bond if
R = primary alkyl (forming analog of B in Eq. (6)). Both
5 and 2 show modest regioselectivity in the reaction
between PhSH and arylacetylenes to afford the same
branched isomer as the major product. However, geome-
tries of the minor linear isomers make a sharp contrast, as
trans-p-MeOC6H4CH@CHSPh was formed by 5 and cis-
p-MeOC6H4CH@CHSPh by 2.
HB
N
2.3. Mechanistic study of the catalysis
N
N
PhSH (1 equiv)
N
N
When 1 was treated with an equimolar amount of PhSH,
the hydride–thiolate complex [Tp*RhH(SPh)(MeCN)] (6)
was predominantly formed via oxidative addition of PhSH
together with bis(thiolate) complex 2 and unreacted 1 (Eq.
(7)) [29]. Treatment of 1 with excess PhSH afforded 2 in
SPh + 2 + 1
(7)
1
N
Rh
H
THF, 20 ˚C,10 min
N
C
Me
6
(6 : 2 : 1 = 6 : 3 : 1)
1
higher yield with concomitant formation of H2. H NMR
spectrum of 6 in C6D6 shows a hydrido signal at d ꢀ13.79,
which is coupled with a Rh atom at 11.6 Hz. Three pyrazolyl
groups are observed inequivalently, and a singlet for one
MeCN ligand appears at d 0.36. In contrast to 2, 6 showed
It is most probable that the catalytic cycle to afford the
branched product R(PhS)C@CH2 proceeds according to
the cycle depicted in Scheme 1. Coordinatively unsaturated
1
PhSH
HC≡CR
no reaction
6
2
PhSH
– MeCN
HB
N
N
N
N
N
trans-linear
HC≡CR
N
Rh SPh
SPh
H
SPh
fast
A
R
H
H
SPh
+
branched
H
H
R
slow
HB
HB
N
N
R
N
N
N
N
PhSH
N
N
N
N
N
Rh SPh
N
Rh SPh
Ph
S
Ph
S
H
R
H
B
4
Scheme 1.

Y. Misumi et al. / Journal of Organometallic Chemistry 691 (2006) 3157–3164
3161
species A generated by dissociation of MeCN from 2 reacts
regioselectively with RC„CH to form 4, whose proton-
ation by PhSH followed by coordination of the resulting
PhSꢀ and liberation of the product regenerate A. Alkylacet-
ylenes are considered to react in such a simple manner,
exhibiting high selectivity, but other reaction pathways
may exist in less selective reactions of arylacetylenes. If
C–S bond formation occurs at the terminal side of RC„CH
in a certain ratio, it may lead to B, in which R group will
heavily congest with dimethylpyrazolyl moieties in Tp*. In
fact, the protonation product of B, trans-RCH@CHSPh,
could not be detected, neglecting the path to B.
To clarify detailed mechanism, the reactions of PhSH
and p-MeOC6H4C„CH using 2 under various conditions
were monitored by NMR spectroscopy. Typical time
course of the reaction is shown in Fig. 3, where the
increase of two products, the branched isomer p-MeOC6H4-
(PhS)C@CH2 and the cis-linear cis-p-MeOC6H4CH@
CHSPh, corresponds well to the consumption of the sub-
strate. As indicated in Figs. 4 and 5, high concentration
of 2 or PhSH increased the rate of the branched isomer
production, while that of alkyne was proved to show no
influence essentially (Fig. 6). These observations suggest
that the rate determining step of the catalytic cycle is
the interaction of 4 with PhSH to liberate the branched
isomer, and that the reaction of A with alkyne to form
4 is quite a fast step. On the other hand, formation of
the cis-linear isomer was highly dependent on concentra-
tion of alkyne (Fig. 6) but not affected by 2 or PhSH.
Therefore, it is concluded that the linear isomer have
independently been formed via nucleophilic [32,33] or
radical [27,34] mechanisms. Formation of the thioketal
p-MeOC6H4C(SPh)2CH3 is also rationalized by Mark-
ovnikov addition of PhSH to p-MeOC6H4(PhS)C@CH2.
Fig. 4. Time course of the yield of p-MeOC6H4(PhS)C@CH2 under
different catalyst concentrations. Initial conditions: [PhSH]0 = [p-
MeOC6H4C„CH]0 = 70 mmol Lꢀ1 (all), [2] = 5 (circle), 10 (square), 15
(triangle) mmol Lꢀ1
.
Fig. 5. Time course of the yield of p-MeOC6H4(PhS)C@CH2 with
different amounts of PhSH. Initial conditions: [p-MeOC6H4-
C„CH]0 = 70 mmol Lꢀ1, [2] = 5 mmol Lꢀ1 (all), [PhSH]0 = 70 (circle),
140 (square), 210 (triangle) mmol Lꢀ1
.
In summary, Tp–Rh complexes 1 and 2 have been found
to catalyze addition reaction of PhSH to alkylacetylenes
with high activity and excellent selectivity, where the key
intermediate involved in the catalytic cycle has been fully
characterized.
3. Experimental
Fig. 3. Time course of the reaction of PhSH and p-MeOC6H4C„CH
catalyzed by 2 in C6D6 at 50 ꢀC. Initial conditions: [PhSH]0 = [p-
MeOC6H4C„CH]0 = 70 mmol Lꢀ1, [2] = 10 mmol Lꢀ1. Open and filled
circles represents the yields of p-MeOC6H4(PhS)C@CH2 and cis-p-
All manipulations were performed under nitrogen atmo-
sphere using standard Schlenk techniques. Solvents were
dried by common procedures and distilled under nitrogen
before use. Complexes 1 [22] and 2 [20] were prepared
MeOC6H4CH@CHSPh, respectively, and denotes the percentage quantity
*
of p-MeOC6H4C„CH (100 · [p-MeOC6H4C„CH]/[p-MeOC6H4C„CH]0).

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Y. Misumi et al. / Journal of Organometallic Chemistry 691 (2006) 3157–3164
10.91. Found: C, 58.95; H, 5.89; N, 11.29%. 1H NMR
(C6D6): d (major isomer) 1.63, 2.21, 2.22, 2.30, 2.41, 2.74
(s, 3H each, Me in Tp*), 3.6–3.75 (m, 2H, CH2), 5.40,
5.44, 5.61 (s, 1H each, CH in Tp*), 6.5–7.8 (m, 15H, Ph),
8.59 (dt, JRh–H = 3.2, JH–H = 1.2 Hz, 1H, RhCH), (minor
isomer) 1.94, 2.14, 2.17, 2.30, 2.33, 2.61 (s, 3H each, Me
in Tp*), 3.27, 3.58 (dd, JH–H = 16, 1.2 Hz, 1H each,
CH2), 5.31, 5.49, 5.53 (s, 1H each, CH in Tp*), 6.5–7.8
(m, 15H, Ph), 8.73 (dt, JRh–H = 3.0, JH–H = 1.2 Hz, 1H,
RhCH), major:minor = 1:0.9, ca. 0.5 molar amount of
THF (d 1.40 and 3.57) was detected. IR (KBr): 2520
(mB–H) cmꢀ1
.
3.3. Synthesis of [Tp*Rh(SPh){g2-CH@CPh(SPh)}] (4b)
Reaction of 2 (66 mg, 0.10 mmol) and PhC„CH
(17 lL, 0.15 mmol) was carried out according to the above
method for 4a. Extraction with ether followed by concen-
tration and standing at ꢀ20 ꢀC gave purple crystals of
4b Æ 0.25(Et2O) (31 mg, 42% yield). Anal. Calc. for
C36H40.5N6O0.25BS2Rh: C, 58.50; H, 5.52; N, 11.37.
Fig. 6. Formation of p-MeOC6H4(PhS)C@CH2 (open marks) and cis-p-
MeOC6H4C@CHSPh (filled marks) with different amounts of alkyne.
Initial conditions: [PhSH]0 = 70 mmol Lꢀ1, [2] = 5 mmol Lꢀ1 (all), [p-
MeOC6H4C„CH]0 = 35 (square), 70 (circle), 140 (triangle).
1
Found: C, 57.95; H, 5.54; N, 10.98%. H NMR (C6D6): d
according to the literature methods. Other reagents were
commercially available and used as received.
(major isomer) 2.03, 2.14, 2.21, 2.33, 2.44, 2.82 (s, 3H each,
Me in Tp*), 5.44, 5.45, 5.59 (s, 1H each, CH in Tp*), 6.3–
7.7 (m, 15H, Ph), 9.82 (d, JRh–H = 3.2 Hz, 1H, RhCH),
(minor isomer) 1.63, 2.19, 2.20, 2.32, 2.72, 2.83 (s, 3H each,
Me in Tp*), 5.34, 5.51, 5.69 (s, 1H each, CH in Tp*), 6.3–
7.7 (m, 15H, Ph), 9.57 (d, JRh–H = 3.6 Hz, 1H, RhCH),
major:minor = 1:0.5, ca. 0.25 molar amount of Et2O (d
NMR spectra (1H at 400 MHz and 13C at 100.5 MHz)
were recorded on a JEOL alpha-400 spectrometer, and
chemical shifts were referenced using those of residual sol-
vent resonances (CDCl3 at dH 7.26 and dC 77.00, and C6D6
at dH 7.15 ppm). IR spectra were recorded on a JASCO
FT/IR-420 spectrometer. Elemental analyses were done
with a Perkin–Elmer 2400 series II CHN analyzer.
1.11 and 3.25) was detected. IR (KBr): 2526 (mB–H) cmꢀ1
.
3.4. Catalytic addition of PhSH to RCH2CCH by using 1
3.1. Synthesis of [Tp*Rh(SPh)2(XyNC)] (3)
To a solution of 1 (14 mg, 0.025 mmol) in THF (3 mL)
were added PhCH2C„CH (63 mg, 0.54 mmol) and PhSH
(61 mg, 0.55 mmol) at 0 ꢀC, and the mixture was stirred
at 50 ꢀC for 7 h. After evaporation of volatiles under vac-
uum at room temperature, the residual oil was purified
by column chromatography on silica gel using hexane–
ether as eluent to provide PhCH2(PhS)C@CH2 (112 mg,
92%). Anal. Calc. for C15H14S: C, 79.60; H, 6.23. Found:
A THF solution (5 mL) of 2 (68 mg, 0.10 mmol) and
XyNC (28 mg, 0.21 mmol) was stirred at room temperature
for 17 h. The resulting red solution was concentrated to
2 mL followed by addition of hexane (18 mL). Red crystals
of 3 were filtered off and dried in vacuum (51 mg, 68%
yield). Anal. Calc. for C36H41N7BS2Rh: C, 57.68; H, 5.51;
1
N, 13.08. Found: C, 57.62; H, 5.55; N, 12.90%. H NMR
1
(C6D6): d 2.12, 2.13 (s, 6H each, Me in Xy and Tp*), 2.21,
3.34 (s, 3H each, Me in Tp*), 2.49 (s, 6H, Me in Tp*),
5.48 (s, 2H, CH in Tp*), 5.56 (s, 1H, CH in Tp*), 6.52 (d,
2H, 3,5-H in Xy), 6.54 (t, 1H, 4-H in Xy), 6.6–7.2 (m,
C, 79.74; H, 6.35%. H NMR (CDCl3): d 3.53 (br s, 2H,
CH2Ph), 5.00 (s, 1H, @CH2), 5.12 (t, J = 1.2 Hz, 1H,
@CH2), 7.2–7.5 (m, 10H, Ph). 13C{1H} NMR (CDCl3): d
42.95 (CH2Ph), 114.65 (@CH2), 126.62, 127.99, 128.43,
129.12, 129, 21, 133.01, 133.41, 138.44 (Ph), 145.22
(C@CH2).
Reaction of PhSH (58 mg, 0.52 mmol) and n-
C6H13C„CH (56 mg, 0.51 mmol) in a similar procedure
followed by chromatography (silica gel, hexane as eluent)
afforded n-C6H13(PhS)C@CH2 (65 mg, 58% yield). 1H
NMR (CDCl3): d 0.88 (t, J = 6.8 Hz, 3H, CH3), 1.2–1.35
(m, 6H, CH2), 1.5–1.6 (m, 2H, CH2), 2.23 (t, J = 7.2 Hz,
2H, CH2C@), 4.86, 5.14 (s, 1H each, @CH2), 7.25–7.45
(m, 5H, Ph). 13C{1H} NMR (CDCl3): d 14.16 (CH3),
22.64, 28.43, 28.63, 31.64, 36.59 ((CH2)5), 112.38 (@CH2),
127.62, 128.99, 133.12, 133.15 (Ph), 146.04 (C@CH2).
10H, Ph). IR (KBr): 2527 (mB–H), 2192 (mN„C) cmꢀ1
.
3.2. Synthesis of [Tp*Rh(SPh){g2-CH@C(CH2Ph)-
(SPh)}] (4a)
To a THF solution (5 mL) of 2 (66 mg, 0.10 mmol) was
added PhCH2C„CH (19 lL, 0.15 mmol) at 0 ꢀC. After
stirring the mixture for 4 h at 0 ꢀC, the resulting purple
solution was concentrated to 2 mL. After addition of hex-
ane (18 mL), the mixture was stored at ꢀ20 ꢀC, yielding
purple crystals of 4a Æ 0.5THF (20 mg, 26% yield). Anal.
Calc. for C38H44O0.5N6BS2Rh: C, 59.22; H, 5.75; N,

Y. Misumi et al. / Journal of Organometallic Chemistry 691 (2006) 3157–3164
3163
Table 3
3.5. Catalytic addition of PhSH to p-MeOC6H4CCH by
using 2
Crystallographic data for 3 and 4a Æ 0.5THF
3
4a Æ 0.5THF
A THF solution (3 mL) of PhSH (55 mg, 0.50 mmol),
Formula
C36H41BN7S2Rh
749.60
C38H44BN6O0.5S2Rh
770.64
Formula weight
Space group
p-MeOC6H4C„CH (66 mg, 0.50 mmol), and 2 (33 mg,
0.050 mmol) was stirred at 50 ꢀC for 9 h. Volatiles were
evaporated under vacuum at room temperature, and the
residue was chromatographed on silica gel with hexane–
toluene to provide a 3:1 mixture (76 mg, 63% yield) of
ꢀ
P21/c (#14)
11.004(1)
18.056(2)
18.707(2)
90
103.2432(5)
90
3617.9(8)
4
P1 ð#2Þ
˚
a (A)
12.004(5)
13.019(4)
13.593(5)
67.48(2)
85.81(2)
71.28(2)
1855(1)
2
˚
b (A)
˚
c (A)
a (ꢀ)
b (ꢀ)
c (ꢀ)
p-MeOC6H4(PhS)C@CH2
and
cis-p-MeOC6H4CH@
CHSPh as the first fraction and p-MeOC6H4C(SPh)2CH3
(32 mg, 18% yield based on alkyne) as the second. Mixture
of p-MeOC6H4(PhS)C@CH2 and cis-p-MeOC6H4CH@
CHSPh: Anal. Calc. for C15H14OS: C, 74.34; H, 5.82.
Found: C, 74.42; H, 5.41%. p-MeOC6H4(PhS)C@CH2:
1H NMR (CDCl3): d 3.78 (s, 3H, OMe), 5.24, 5.59 (s,
1H each, @CH2), 6.82, 7.55 (d, J = 8.8 Hz, 2H each,
C6H4), 7.15–7.45 (m, 5H, Ph). 13C{1H} NMR (CDCl3):
3
˚
V (A )
Z
ꢀ3
˚
dcalcd (g A
)
1.376
0.622
8126 (0.019)
1.379
0.609
8142 (0.023)
l (mmꢀ1
Number of unique
reflections (Rint
)
)
Number of reflections
F 2o > 2rðF 2oÞ
6525
5336
Number of variables
468
0.031
0.096
1.018
474
0.048
0.143
1.018
a
R1 ðF 2o > 2rðF 2oÞÞ
d
55.26 (OMe), 114.68 (@CH2), 143.55 (C@CH2),
b
wR2 (all data)
113.55, 127.03, 128.32, 128.91, 131.07, 131.55, 134.03,
159.68 (aromatic). cis-p-MeOC6H4CH@CHSPh: 1H
NMR (CDCl3): d 3.83 (s, 3H, OMe), 6.37, 6.56 (d,
J = 10.8 Hz, 1H each, CH@CH), 6.93, 7.49 (d,
J = 8.8 Hz, 2H each, C6H4), 7.1–7.5 (m, 5H, Ph).
13C{1H} NMR (CDCl3): d 55.30 (OMe), 123.15, 127.11
(CH@CH), 113.65, 126.92, 129.03, 129.20, 129.77,
130.07, 136.31, 158.52 (aromatic). p-MeOC6H4C-
(SPh)2CH3: Anal. Calc. for C15H14OS: C, 71.55; H, 5.72.
Found: C, 71.75; H, 5.66%. 1H NMR (CDCl3): d 1.80
(s, 3H, CMe), 3.82 (s, OMe), 6.81, 7.51 (d, J = 9.0 Hz,
2H each, C6H4), 7.2—7.35 (m, 10H, Ph). 13C{1H} NMR
(CDCl3): d .27.75 (CMe), 55.30 (OMe), 63.56 (CMe),
113.08, 128.31, 128.76, 128.78, 132.59, 135.39, 136.24,
158.61 (aromatic).
Goodness-of-fitc
Maximum/minimum
eꢀ density
1.18/ꢀ0.45
1.25/ꢀ0.88
P
P
a
R1 = ||Fo| ꢀ |Fc||/ |Fo|.
P
P
2
2 1=2
b
c
wR2 ¼ ½ wðF 2o ꢀ F c2Þ = wðF 2oÞ ꢂ
.
P
2
1=2
Goodness-of-fit ¼ ½ wðF 2o ꢀ F c2Þ =fðno: uniqueÞ ꢀ ðno: variablesÞgꢂ
.
chromatized Mo Ka source. All diffraction studies were
done at 23 ꢀC, whose details are listed in Table 3.
Structure solution and refinements were carried out by
using the CRYSTALSTRUCTURE program package [35]. The
positions of the non-hydrogen atoms were determined by
Patterson methods (PATTY [36]) and subsequent Fourrier
synthesis (DIRDIF99 [37]), and they were refined with aniso-
tropic thermal parameters by full-matrix least-squares tech-
niques. The THF molecule in 4a Æ 0.5THF disordered
around the inversion center was refined isotropically with
0.5 atom occupancies and restraints. Hydrogen atoms
bound to B atom and those bound to C(28) and C(30) in
4a Æ 0.5THF were found in the Fourier maps and isotropi-
cally refined, while the other hydrogens were placed at the
calculated positions. Refinements were done by using all
unique data within the limits of 6.2ꢀ < 2h < 55ꢀ.
3.6. Reaction of 1 with PhSH
To a THF solution (5 mL) of 1 (62 mg, 0.11 mmol) was
added PhSH (12 mg, 0.11 mmol), and the mixture was stir-
red at 20 ꢀC for 10 min. NMR measurement of the result-
ing solution revealed existence of [Tp*RhH(SPh)(MeCN)]
(6), 2, and 1 in a 6:3:1 ratio. After addition of p-
MeOC6H4C„CH (14 mg, 0.11 mmol) to the solution and
standing for 10 min, signals of 1 and 2 disappeared while
those of 6 remained unchanged. 1H NMR (C6D6): d
ꢀ13.79 (d, JRh–H = 11.6 Hz, 1H, RhH), 0.36 (s, 3H,
MeCN), 2.07, 2.15, 2.31, 2.32, 2.72, 2.84 (s, 3H each, Me
in Tp*), 5.42, 5.64, 5.86 (s, 1H each, CH in Tp*), 6.94 (br
t, JH–H ꢁ 7.4 Hz, 2H, m-H in Ph), 8.15 (dd, JH–H = 8.4,
1.2 Hz, 2H, o-H in Ph), signal of p-H in Ph is overlapping
with that of C6HD5.
Acknowledgements
This work was supported by a Grant-in-Aid for Scien-
tific Research on Priority Areas (No. 14078206, ‘‘Reaction
Control of Dynamic Complexes’’) from the Ministry of
Education, Culture, Sports, Science and Technology, Ja-
pan and by CREST of JST (Japan Science and Technology
Agency). We also thank Ms. Chihiro S. Mochizuki of Ko-
gakuin University for elemental analysis.
3.7. Crystallographic study
Appendix A. Supplementary material
Single crystals of 3 and 4a Æ 0.5THF were sealed in glass
capillaries under argon and mounted on a Rigaku Mer-
cury–CCD diffractometer equipped with a graphite mono-
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic Data

3164
Y. Misumi et al. / Journal of Organometallic Chemistry 691 (2006) 3157–3164
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