A novel approach towards the preparation of functionalized alkyne derivatives via ArS-mediated AdE reaction of cobaltcarbonyl complexed conjugated enynes

Article abstract of DOI:10.1016/j.tet.2010.01.060

A unified protocol of three-component coupling of arenesulfenyl chloride, dicobalthexacarbonyl complexed conjugated enynes, and nucleophiles of π-donor type is applied for the synthesis of functionalized alkynes.

Full text of DOI:10.1016/j.tet.2010.01.060

Tetrahedron 66 (2010) 2156–2161
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A novel approach towards the preparation of functionalized alkyne derivatives via
ArS-mediated AdE reaction of cobaltcarbonyl complexed conjugated enynes
*
Vasily V. Tumanov , Georgy V. Zatonsky, William A. Smit
N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prosp. 47, Moscow 119991, Russian Federation
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 9 June 2009
Received in revised form 10 December 2009
Accepted 18 January 2010
Available online 22 January 2010
A
unified protocol of three-component coupling of arenesulfenyl chloride, dicobalthexacarbonyl
complexed conjugated enynes, and nucleophiles of
tionalized alkynes.
p
-donor type is applied for the synthesis of func-
Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction
2. Results and discussion
Alkylation of
p
-nucleophiles with cobaltcarbonyl complexed
DCHCcomplexes ofvinylacetylene(1a) andisopropenylacetylene
(1b) were chosen as the model substrates in the reaction sequence
shown in Scheme 2. p-Chlorobenzene sulfenyl chloride was used as
a starting electrophile in step (i). Its addition across the double bond
of enyne complexes 1 proceeds smoothly even at ꢀ70 ꢁC with an
almost quantitative yield (as assessed by TLC data). Arylthio-
chloroadducts2 arestable atleast forseveralhoursin solutionwithin
the temperature range from ꢀ70 ꢁC up to ꢀ20 ꢁC. However, attempts
to isolate them failed due to their lability; at temperatures above
ꢀ20 ꢁC elimination products 3 were immediately formed.
propargylic cations (Nicholas reaction)1,2 is widely employed as
one of the most effective and convenient methods for the
preparation of various functionalized alkynes (Scheme 1, Eq. 1).
A useful modification of this reaction involves the controlled
two-step sequence of AdE reactions across the double bond of
dicobalthexacarbonyl (DCHC) complexes of the conjugated
enynes3,4 (Eq. 2).
(OC) Co
Co(CO)
(eq. 1)
(OC) Co
RO
Co(CO)
(OC) Co
Co(CO)
H+ or
Lewis acid
NuC
+
(OC) Co
Co(CO)
(OC) Co
ArS
Co(CO)
(OC) Co
Co(CO)
Nu
Nu
ii
iii
i
R
Cl
ArS
(OC) Co
Co(CO)
(OC) Co
Co(CO)
(OC) Co
E
Co(CO)
(eq. 2)
R
2a,b
R
6-16
1a,b
E+
NuC
+
Ar = p-ClC H ; R = H (1a, 2a), Me (1b, 2b).
ii: Lewis acid;
Nu
i: ArSCl, CH Cl , -70 oC;
iii: NuC (5a-g, see Tables 1 and 2).
E
E+ = Ac+, t-Alk, Ar2CH+
NuC = enol silanes, allyl silanes
(OC) Co
ArS
Co(CO)
(OC) Co
ArS
Co(CO)
Scheme 1.
3
4
OH
R
R
Here we present a new option of the modified Nicholas reaction
based upon the use of arylsulfenium chlorides as the starting
electrophiles in the abovementioned sequence (Eq. 2, Eþ¼ArSþ; for
the preliminary results see Ref. 5).
Scheme 2.
Under treatment of 2a,b with water elimination and partial
hydrolysis occur to furnish the respective products (3 and 4) in
variable amounts. The adducts 2 formed in situ were directly
treated with a Lewis acid (step ii) and then with the respective
carbon nucleophile (NuC, step iii, Scheme 2).
* Corresponding author. Fax: þ7 495 135 5328.
E-mail address: vasilii_tumanov@mail.ru (V.V. Tumanov).
0040-4020/$ – see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2010.01.060

V.V. Tumanov et al. / Tetrahedron 66 (2010) 2156–2161
2157
Both complexes 2a,b turned out to be reactive toward a series of
standard silyl-capped -donors (5a–g) lying within the range of N
alcohol9 (Scheme 3). In fact, as was shown earlier,9 cation 18
reacts rapidly with 1-trimethylsilyloxycyclohexene 5g at ꢀ78 ꢁC,
whereas analogous transformation of 17a into 15 (Table 2, entry
3) requires up to 24 h at ꢀ30 ꢁC to proceed to completion. It is
also noteworthy that the rate of the latter reaction depends on
the Lewis acid used.
Moreover, the stereoselectivity for Nicholas reactions involving
DCHC complexes of terminal alkynes and prochiral enolates is
usually poor.2,9,10
p
values 4–9 (according to Mayr’s scale of nucleophilicities).6 More
reactive nucleophiles (for example, enamines) exhibited high
basicity and their reactions afforded only the elimination products
3. A list of representative examples (Tables 1 and 2) demonstrates
that the reaction sequence is applicable to virtually all combina-
tions of the substrates employed; the respective products 6–16
were obtained in good to high yields.
Table 1
Alkylation of
p-donors with DCHC complexed 1,3-enynes/ArSCl adducts according to Scheme 2
Entry
Enyne
NuC
Lewis acid
Product
Yield (%)
90
(OC)3Co
ArS
Co(CO)3
OSiMe3
O
1
2
1a
EtAlCl2
(5a)
(6)
EtAlCl2
TMSOTf
Bu2BOTf
LiClO4/MeNO2
AgSbF6
96
40
38
27
40
(OC)3Co
Co(CO)3
O
OSiMe3
1b
1a
(5a)
(7)
ArS
(OC)3Co
ArS
Co(CO)3
O
OSiMe3
3
EtAlCl2
94
(8)
(5b)
OMe
OMe
(OC)3Co
Co(CO)3
SiMe3
4
5
6
1a
1b
1b
EtAlCl2
EtAlCl2
EtAlCl2
81
82
80
(9)
(5c)
ArS
(OC)3Co
Co(CO)3
Co(CO)3
SiMe3
(10)
(5c)
ArS
(OC)3Co
SiMe3
(5d)
(11)
ArS
SiMe3
(5e)
(OC)3Co
Co(CO)3
7
1a
EtAlCl2
61
(12)
ArS
SiMe3
SiMe3
Various Lewis acids acted as efficient reaction promoters. While
the utilization of AgSbF6, TMSOTf, Bu2BOTf, and the LiClO4/MeNO2
system furnished the desired products in rather modest yields
(Table 1, entry 2; Table 2, entries 1 and 2), the use of EtAlCl2, TiCl4,
and ZnCl2/Et2O turned out to be optimal in most cases.7
We found out that the secondary b-arylthiosubstituted cation
17a prepared from 1a reacts with 1-trimethylsilyloxycyclopentene
5f and 1-trimethylsilyloxycyclohexene 5g to give the corre-
sponding adducts with good to excellent syn-diastereoselectivity
(Table 2, entries 1 and 3) presumably due to the stereodirecting
effect of the adjacent ArS-substituent. For 13 and 15 the stereo-
chemistry of the major isomer was rigorously established (see Ex-
perimental); that of 14 and 16 was assumed by analogy.
Surprisingly, a noticeable diastereoselection was observed even for
the reactions involving a formation of the tertiary cationic in-
termediate 17b (entries 2 and 4).11
By analogy with the ample literature precedent8 we assume that
the interaction of 2 with a Lewis acid (step ii) affords the bridged
cationic species, e.g., 17. Such a description implies a contribution of
the sulfur atom into the stabilization of the carbocation. Although
we have no direct evidence of this contribution, there are some
observations indicating the validity of this assumption.
First of all,
b
-arylthiosubstituted cation 17a was found to be
The structures of all compounds 6–16 were ascertained by 1H
and 13C NMR spectra and/or by the consistent analytical and NMR
spectral data of the decomplexed adducts 60–160, prepared in good
significantly less reactive as compared to the closely similar non-
bridged Nicholas’ cation 18, prepared from the respective

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V.V. Tumanov et al. / Tetrahedron 66 (2010) 2156–2161
Table 2
Diastereoselective alkylation of
p-donors with DCHC complexed 1,3-enynes/ArSCl adducts according to Scheme 2
Entry
Enyne
NuC
Lewis acid
Product
Yield (%)
dr (syn/anti)
EtAlCl2
TMSOTf
Bu2BOTf
AgSbF6
ZnCl2/Et2O
TiCl4
94
55
54
40
88
86
3:1
10:1
10:1
20:1
12:1
17:1
OSiMe3
(OC)3Co
ArS
Co(CO)3
O
1
1a
(5f)
H
+ 13-anti
H
13-syn
OSiMe3
(5f)
EtAlCl2
TMSOTf
Bu2BOTf
AgSbF6
95
57
52
55
2.5:1
3.3:1
3.0:1
3.0:1
(OC)3Co
ArS
Co(CO)3
2
1b
O
H
+ 14-anti
Me
14-syn
(OC)3Co
ArS
Co(CO)3
EtAlCl2
ZnCl2/Et2O
TiCl4
86
83
85
7:1
10:1
12:1
O
H
OSiMe3
3
1a
+ 15-anti
H
(5g)
15-syn
(OC)3Co
Co(CO)3
O
H
OSiMe3
(5g)
4
1b
EtAlCl2
87
2.5:1
ArS
+ 16-anti
Me
16-syn
was carried out on plates with silica. Column chromatography was
performed using silica gel (220–240 mesh ASTM). Due to the
thermal lability of DCHC complexes of alkynes, the removal of solvents
was carried out using a rotary evaporator with the water bath at
temperature below 30 ꢁC. Chemical shifts are reported in parts per
(OC) Co
Co(CO)
(OC) Co
Co(CO)
OH
(OC) Co
Co(CO)
HBF / Ac O
+
S+
Ar
R
18
million as follows: chemical shift (
d¼doublet, t¼triplet, q¼quartet, m¼multiplet), coupling constant
d
), multiplicity (s¼singlet,
17a,b
R = H (17a), Me (17b)
(J, in hertz), and integration.
Scheme 3.
Vinylacetylene was prepared from 2-methylhex-5-en-3-yn-2-ol
in accordance with the described method;13 the known procedures
were modified for the preparation of the DCHC complex of vinyl-
acetylene (1a)14 and DCHC complex of isopropenylacetylene (1b)3b
(vide infra). p-Chlorobenzene sulfenyl chloride was prepared as
described previously,15 stored and used as a 1.0 M solution in
CH2Cl2. Silyl ketene acetal (5b),16 silyl ethers (5a,f,g),17 meth-
allylsilane (5d),18 and silylated enyne (5e)19 were prepared using
the described methods. The preparation of 2-(trimethylsilylme-
thyl)buta-1,3-diene (5c)20 was carried out using the modified
method (vide infra) described earlier; other reagents were used as
received from commercial sources unless otherwise noted.
yields using the standard oxidative procedure9 with cerium(IV)
ammonium nitrate (Scheme 4).
(OC) Co
ArS
Co(CO)
Nu
(NH ) Ce(NO )
acetone, - 50 °C
ArS
Nu
R
R
6'-16', 80-95%
6-16
Scheme 4.
In conclusion, we have presented a novel and efficient pathway
for the one-pot preparation of the functionalized alkynes bearing
ester-, keto-, allylic, or dienic fragments. Some of these products
(e.g., 9 and 10) can be considered as the substrates directly
amenable for intramolecular cyclizations (for example, the Pauson–
Khand reaction).12 Further synthetic ramifications of these results
are under intense study in our group.
3.2. Syntheses of the starting materials
3.2.1. DCHC complex of vinylacetylene (1a)14
.
(OC)3Co
Co2(CO)8
Co(CO)3
3. Experimental
ether
3.1. General information
Vinylacetylene (1.21 g, 22.0 mmol) was dissolved in ether
(100 ml), Co2(CO)8 (6.84 g, 20.0 mmol) was added to the solution
and the mixture was stirred until the evolution of CO ceased
(40 min). The reaction mixture was twice filtered through a thin
All experiments were carried out under dry argon, using anhy-
drous solvents purified using the standard methods. TLC analysis

V.V. Tumanov et al. / Tetrahedron 66 (2010) 2156–2161
2159
layer of silica gel using ether as the eluent. After evaporation of the
solvent the residue was dissolved in hexane and again filtered
through silica gel using hexane as the eluent. Removal of the
solvent furnished compound 1a (6.15 g, 91%) as a dark brownish oil
(Rf 0.70, SiO2, hexane). A 1.0 M solution of complex 1a was stored in
CH2Cl2 at ꢀ30 ꢁC and was used as a stock solution.
was filtered through a silica gel and evaporated. The residue after
solvent removal was purified by chromatography on silica gel to
give the adduct 6 (486 mg, 90%) as a dark brownish oil (Rf 0.32,
ethyl acetate/hexane, 1:10). Cobaltcomplexed alkynes thus prepared
were quite stable when stored in a fridge at least for several weeks. It is
not advisable to concentrate extracts without preliminary purification
and to keep them at ambient temperature for a long time.21 The
adduct 6 was then converted into the decomplexed derivative 60
(94%) by the oxidation with CAN.9
3.2.2. DCHC complex of isopropenylacetylene (1b)15
.
(OC)3Co
Co(CO)3
Compound 60: Rf 0.30 (SiO2, ethyl acetate/hexane, 1:10). 1H NMR
(200 MHz, CDCl3): 2.17 (s, 1H), 2.20 (s, 1H), 2.79 (dd, 1H, J1¼17.3,
J2¼6.6), 2.88 (dd, 1H, J1¼17.3, J2¼5.4), 3.02–3.20 (m, 3H), 7.31 and
7.37 (both d, 2H each, J¼8.8). 13C NMR (300 MHz, CDCl3): 27.9, 31.2,
39.4, 47.8, 71.7, 85.5, 130.1, 132.3, 133.6, 134.9, 206.5. Elemental
analysis calcd (%) for C13H13ClOS: C, 61.77; H, 5.18. Found (%): C,
61.87; H, 5.26.
(OC)3Co
Co(CO)3
BF3·Et2O
CH2Cl2 /acetone
OH
To a stirred solution of DCHC complex of dimethylethynyl
carbinol (3.70 g, 10.0 mmol) in CH2CI2 (50 ml) freshly distilled
BF3$Et2O (0.45 g, 4.0 mmol) followed by acetone (2.0 ml) were
*
added at 20 ꢁC. The mixture was stirred for an additional 5 min and
then quenched by Et3N (0.45 g, 4.5 mmol) and filtered through
SiO2. After removal of the solvent, the residue was dissolved in
hexane and additionally filtered through SiO2. Removal of the
solvent under reduced pressure gave complex 1b (3.31 g, 94%).
*Note: the presence of acetone was found to be crucial in order to
avoid the formation of by-products.
3.3.2. DCHC complex of 4-methyl-4-[(4-chlorophenylthio)methyl]-
hex-5-yn-2-one (7). Following the procedure described for 6, the
DCHC complex of isopropenylacetylene 1b (352 mg, 1.0 mmol) and
2-trimethylsilyloxypropene (5a) (195 mg, 1.5 mmol) were con-
verted into the adduct 7 (532 mg, 96%), dark brownish oil.
Compound 7: Rf 0.33 (SiO2, ethyl acetate/hexane, 1:10). 1H NMR
(200 MHz, CDCl3): 1.46 (s, 3H), 2.07 (s, 3H), 2.77 and 2.89 (both d,
J¼18.1,1H each), 3.32 and 3.46 (both d, J¼11.9,1H each), 6.24 (s, 1H),
7.25 (s, 4H).
3.2.3. 2-(Trimethylsilylmethyl)buta-1,3-diene (5c)20
.
Compound 70: 91% from 7, Rf 0.31 (SiO2, ethyl acetate/hexane,
1:10). 1H NMR (500 MHz, CDCl3): 1.39 (s, 3H), 2.14 (s, 3H), 2.22 (s,
1H), 2.69 and 2.79 (both d, J¼16.1, 1H each), 3.29 (s, 2H), 7.23 and
7.33 (both d, J¼8.8, 2H each). Elemental analysis calcd (%) for
C14H15ClOS: C, 63.03; H, 5.67. Found (%): C, 63.28; H, 5.85.
TMP-H, t-BuOK, n-BuLi, TMSCl
THF
SiMe3
Solutions of 2,2,6,6-tetramethylpiperidine (TMP) (7.19 g,
51.0 mmol) in dry THF (5 ml) and t-BuOK (6.71 g, 55.0 mmol) in dry
THF (25 ml) were placed into a three-necked flask and cooled to
ꢀ100 ꢁC. Then a 1.64 M solution of n-BuLi in hexane (30.5 ml,
50.0 mmol) was added with stirring over 5 min keeping the
temperature within the range ꢀ100 ꢁC to ꢀ90 ꢁC. The temperature
of the reaction mixture was gradually increased to ꢀ70 ꢁC over
20 min. The formation of a precipitate, which hindered the stirring,
was observed. A solution of isoprene (1.70 g, 25.0 mmol) in dry THF
(5 ml) was added in one batch and the dark red solution formed
was kept at ꢀ70 ꢁC for an additional 15 min. After that the reaction
mixture was cannulated slowly to a solution of Me3SiCl (5.45 g,
50.0 mmol) in dry THF (50 ml) keeping the temperature below
ꢀ90 ꢁC. The reaction mixture was warmed to ꢀ20 ꢁC, quenched
with water (100 ml), acidified with 0.1 M H2SO4 to pH 4, and
extracted with ether (3ꢂ50 ml). The combined organic extracts
were dried with Na2SO4. The solvent was removed and the residue
was distilled in vacuo to give 6c (1.44 g, 41%), bp 60 ꢁC/30 Torr. 1H
NMR (300 MHz, CDCl3): 0.05 (s, 9H),1.72 (s, 2H), 4.80 (s,1H), 4.90 (s,
1H), 5.13 (d, J¼17.4, 1H), 5.06 (d, J¼10.6, 1H), 6.39 (dd, J1¼17.4,
J2¼10.61, 1H).
3.3.3. DCHC complex of methyl 2,2-dimethyl-3-[(4-chlorophenyl-
thio)methyl]pent-4-ynoate (8). A 1.0 M solution of the DCHC com-
plex of vinylacetylene 1a (1.0 ml,1.0 mmol) was diluted with CH2Cl2
(6 ml) and cooled to ꢀ70 ꢁC. Then a 1.0 M solution of p-ClC6H4SCl
(1.0 ml,1.0 mmol) in CH2Cl2 was added. After 5 min, a 1.0 M solution
of EtAlCl2 in hexane (1.0 ml, 1.0 mmol) was added with the
subsequent addition, after 5 min, of 1-methoxy-2-methylprop-1-
enyloxytrimethylsilane (5b) (209 mg, 1.2 mmol). The reaction
mixture was kept at ꢀ50 ꢁC for 30 min. Further work-up of the
reaction mixture and the isolation of the target compound were
carried out as described above (Section 3.3.1).
Compound 8: 523 mg, 94%, dark brownish oil. Rf 0.22 (SiO2,
ethyl acetate/hexane, 1:10).
Compound 80: 93% from 8, Rf 0.21 (SiO2, ethyl acetate/hexane,
1:10). 1H NMR (300 MHz, CDCl3): 1.25 and 1.31 (2s, 3H each), 2.20
(d, J¼2.3, 1H), 2.89 (dd, J1¼10.6, J2¼12.5, 1H), 2.94 (dd, J1¼3.6,
J2¼12.5,1H), 3.01 (ddd, J1¼2.3, J2¼3.6, J3¼10.6,1H), 3.64 (s, 3H), 7.29
and 7.32 (both d, J¼8.5, 2H each). 13C NMR (75 MHz, CDCl3): 19.7,
25.1, 35.9, 40.4, 45.6, 52.1, 72.5, 82.5, 129.0, 131.3, 132.5, 134.2, 176.3.
Elemental analysis calcd (%) for C15H17ClO2S: C, 60.70; H, 5.77.
Found (%): C, 60.92; H, 5.56.
3.3. Preparation of the products shown in Tables 1 and 2
3.3.4. DCHC complex of 5-[(4-chlorophenylthio)methyl]-3-methyl-
enehept-1-en-6-yne (9). Following the procedure described for 6,
the DCHC complex 1a and diene 5c (210 mg, 1.5 mmol) were con-
verted into the adduct 9.
Compound 9: 445 mg, 81%, dark brownish oil. Rf 0.61 (SiO2, ethyl
acetate/hexane, 1:10). 1H NMR (300 MHz, CDCl3): 2.55 (dd, J1¼5.5,
J2¼14.0, 1H), 2.68 (dd, J1¼7.3, J2¼14.0, 1H), 2.95 (m, 1H), 3.12–3.23
(m, 2H), 5.07 and 5.20 (both s, 1H each), 5.09 (d, J¼11.0, 1H), 5.21 (d,
J¼17.6, 1H), 6.23 (s, 1H), 6.38 (dd, J1¼11.0, J2¼17.6, 1H), 7.25 (s, 4H).
Compound 90: 86% from 9, Rf 0.59 (SiO2, ethyl acetate/hexane,
1:10). Elemental analysis calcd (%) for C15H15ClS: C, 68.56; H, 5.75.
Found (%): C, 68.63; H, 5.82.
3.3.1. DCHC complex of 4-[(4-chlorophenylthio)methyl]-hex-5-yn-2-
one (6). A 1.0 M solution of the DCHC complex of vinylacetylene 1a
(1.0 ml, 1.0 mmol) was diluted with CH2Cl2 (6 ml) and cooled to
ꢀ70 ꢁC. Then a 1.0 M solution of p-ClC6H4SCl (1.0 ml, 1.0 mmol) in
CH2Cl2 was added. After 5 min, a 1.0 M solution of EtAlCl2 in hexane
(1.0 ml, 1.0 mmol) was added followed by the addition, after 5 min,
of 2-trimethylsilyloxypropene (5a) (195 mg, 1.5 mmol). The
reaction mixture was kept at ꢀ30 ꢁC for 1 day and then quenched
with the mixture of saturated aq NaHCO3 and petroleum ether, the
water layer was frozen and organic phase was decanted. After an
additional extraction and decantation the combined organic layer

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V.V. Tumanov et al. / Tetrahedron 66 (2010) 2156–2161
3.3.5. DCHC complex of 5-methyl-5-[(4-chlorophenylthio)methyl]-3-
methylenehept-1-en-6-yne (10). Following the procedure described
for 6, the DCHC complex 1b (352 mg, 1.0 mmol) and diene 5c
(210 mg, 1.5 mmol) were converted into the adduct 10.
Compound 10: 462 mg, 82%, dark brownish oil. Rf 0.61 (SiO2,
ethyl acetate/hexane, 1:10). 1H NMR (250 MHz, CDCl3): 1.33 (s, 3H),
2.54 and 2.77 (both d, J¼13.5, 1H each), 3.09 (s, 2H), 5.13 (d, J¼11.0,
1H), 5.20 and 5.32 (both s,1H each), 5.35 (d, J¼19.0,1H), 6.34 (s,1H),
6.46 (dd, J1¼11.0, J2¼19.0,1H), 7.20 and 7.25 (both d, J¼8.8, 2H each).
Compound 100: 82% from 10, Rf 0.60 (SiO2, ethyl acetate/hexane,
1:10). Elemental analysis calcd (%) for C16H17ClS: C, 69.42; H, 6.19.
Found (%): C, 69.61; H, 6.43.
anti- and syn-, 1H in all), 3.01 (dd, syn-, J1¼13.1, J2¼10.0, 1H), 3.08
(m, anti-, 2H), 3.36 (dd, syn-, J1¼13.1, J2¼4.6, 1H), 3.52 and 3.65
(both m, syn- and anti-, 1H in all), 5.87 and 6.15 (both s, syn- and
anti-,1H in all), 7.27 and 7.31 (2d, syn- and anti-, J¼8.5, 4H in all). 13C
NMR (125 MHz, CDCl3): 20.3, 25.5, 38.5, 39.6, 41.0, 52.6, 129.3,
130.7, 131.2, 132.8, 133.6, 216.30.
Compound 130 (syn/anti): 91% from 13, Rf 0.27 (SiO2, ethyl
acetate/hexane,1:10). 1H NMR (500 MHz, CDCl3): 1.78 (m,1H in all),
1.92 (m, 1H in all), 2.09 (s, 1H in all), 2.11 (m, 3H in all), 2.31 (m, 1H
in all), 2.51 and 2.82 (m, syn- and anti-, 1H in all), 2.93 (dd, syn-,
J1¼11.4, J2¼8.0, 1H), 3.11 (m, 1H in all), 3.15 (dd, syn-, J1¼11.4, J2¼7.5,
1H), 3.27 (m, anti-, 2H), 7.24 and 7.31 (both d, anti-, J¼8.8, 2H each),
7.25 and 7.29 (both d, syn-, J¼8.5, 2H each). 13C NMR (125 MHz,
CDCl3): 20.4, 24.9, 31.3, 37.6, 38.5, 50.2, 72.0, 82.6, 129.3, 131.6,
132.9, 133.3, 209.8. Elemental analysis calcd (%) for C15H15ClOS: C,
64.62; H, 5.42. Found (%): C, 64.81; H, 5.59.
3.3.6. DCHC complex of 2,4-dimethyl-4-[(4-chlorophenylthio)-
methyl]-hex-1-en-5-yne (11). Following the procedure described
for 6, the DCHC complex 1b (352 mg, 1.0 mmol) and methallyl-
trimethylsilane (5d) (192 mg, 1.5 mmol) were converted into the
adduct 11.
Compound 11: 442 mg, 80%, dark brownish oil. Rf 0.57 (SiO2,
ethyl acetate/hexane, 1:10). 1H NMR (250 MHz, CDCl3): 1.41 (s, 3H),
2.26 and 2.61 (both d, J¼13.4,1H each), 3.12 (s, 2H), 4.91 (s,1H), 5.01
(s, 1H), 6.29 (s, 1H), 7.24 (s, 4H).
Compound 110: 82% from 11, Rf 0.55 (SiO2, ethyl acetate/hexane,
1:10). Elemental analysis calcd (%) for C15H17ClS: C, 68.03; H, 6.47.
Found (%): C, 68.30; H, 6.20.
3.3.9. DCHC complex of 2-[2-methyl-1-(4-chlorophenylthio)but-3-
yn-2-yl]cyclopentanone (14). Following the procedure described
for 6, the DCHC complex 1b (352 mg, 1.0 mmol) and trimethyl-
silyloxycyclopentene-1 (5f) (234 mg, 1.5 mmol) were converted
into the mixture of syn/anti isomers of 14 (551 mg, 95%, dark
brownish oil, Rf 0.29 (SiO2, ethyl acetate/hexane, 1:10), syn/
anti¼3.0:1, the ratio was determined by comparison of 1H NMR
signal intensity).
Compound 14 (syn/anti): 1H NMR (500 MHz, CDCl3): 1.38 and
1.42 (both s, syn- and anti-, 3H in all), 1.70 (m, 1H in all), 2.01 (m, 2H
in all), 2.17 (m, 2H in all), 2.34 (m, 1H in all), 2.58 (m, 1H in all), 3.19
and 3.52 (both d, anti-, J¼12.5, 1H each), 3.44 and 3.52 (both d, syn-,
J¼12.5, 1H each), 6.12 and 6.16 (both s, 1H in all), 7.22 and 7.31 (both
d, syn-, J¼8.6, 2H each), 7.23 (s, anti-, 4H).
3.3.7. 1,2-DCHC complex of 7-trimethylsilyl-3-[(4-chlorophenylthio)-
methyl]-3-methyl-5-methylenehepta-1,6-diyne (12). Following the
procedure described for 6, the DCHC complex 1a (338 mg,
1.0 mmol) and 4-trimethylsilyl-2-trimethylsilylmethyl-2-buten-3-
yne (5e) (315 mg, 1.5 mmol) were converted into the adduct 12.
Compound 12: 378 mg, 61%, dark brownish oil. Rf 0.56 (SiO2,
ethyl acetate/hexane, 1:10). 1H NMR (300 MHz, CDCl3): 0.10 (s, 9H),
2.31 (dd, J1¼7.2, J2¼13.8, 1H), 2.74 (dd, J1¼6.8, J2¼13.8, 1H), 3.09 (m,
2H), 3.32 (m, 1H), 5.32 (s, 1H), 5.51 (s, 1H), 6.23 (s, 1H), 7.25 and 7.30
(both d, J¼7.7, 2H each). 13C NMR (75 MHz, CDCl3): 0.3, 40.2, 40.6,
43.6, 75.5, 95.6, 98.6, 103.9, 124.6, 129.4, 130.8, 132.3, 133.6, 134.4,
199.7.
Compound 140 (syn/anti): 92% from 14, Rf 0.27 (SiO2, ethyl ace-
tate/hexane, 1:10). 1H NMR (250 MHz, CDCl3): 1.29 and 1.45 (both s,
anti- and syn-, 3H in all), 1.72 (m, 1H in all), 2.14 and 2.17 (both s,
anti- and syn-, 1H in all), 1.85–2.53 (m, 6H in all), 3.24 and 3.40
(both d, syn-, J¼12.5,1H each), 3.61 (s, anti-, 2H), 7.24 and 7.35 (both
d, syn-, J¼8.8, 2H each), 7.23 and 7.37 (both d, anti-, J¼8.8, 2H each).
Elemental analysis calcd (%) for C16H17ClOS: C, 65.63; H, 5.85. Found
(%): C, 65.69; H, 5.76.
Compound 120: 80% from 12, Rf 0.53 (SiO2, ethyl acetate/hexane,
1:10). Elemental analysis calcd (%) for C18H21ClSSi: C, 64.93; H, 6.36.
Found (%): C, 65.30; H, 6.09.
3.3.10. DCHC complex of 2-[1-(4-chlorophenylthio)but-3-yn-2-yl]-
cyclohexanone (15). A 1.0 M solution of the DCHC complex of
vinylacetylene 1a (1.0 ml, 1.0 mmol) was diluted with CH2Cl2 (6 ml)
and cooled to ꢀ70 ꢁC. Then a 1.0 M solution of p-ClC6H4SCl (1.0 ml,
1.0 mmol) in CH2Cl2 was added. After 5 min, a 1.0 M solution of
TiCl4 in CH2Cl2 (1.1 ml, 1.1 mmol) was added with the subsequent
addition, after 5 min, of 1-trimethylsilyloxycyclohexene-1 (5g)
(255 mg, 1.5 mmol). The reaction mixture was kept at ꢀ30 ꢁC for 1
day. Further work-up of the reaction mixture and the isolation of
the target compound were carried out as described in the typical
experimental procedure in the main text. Product 15 was isolated
as a mixture of syn/anti diastereomers (493 mg, 85%, dark brownish
oil, Rf 0.33 (SiO2, ethyl acetate/hexane, 1:10), syn/anti¼12:1, the
ratio was determined by comparison of 1H NMR signal intensity).
Stereochemical assignment was accomplished in the same manner
as for product 13.
3.3.8. DCHC complex of 2-[1-(4-chlorophenylthio)but-3-yn-2-yl]-
cyclopentanone (13). A 1.0 M solution of the DCHC complex of
vinylacetylene 1a (1.0 ml, 1.0 mmol) was diluted with CH2Cl2 (6 ml)
and cooled to ꢀ70 ꢁC. Then a 1.0 M solution of p-ClC6H4SCl (1.0 ml,
1.0 mmol) in CH2Cl2 was added. After 5 min, a 1.47 M ZnCl2/Et2O
catalyst7 (0.10 ml, 0.15 mmol) was added with the subsequent ad-
dition, after 5 min, of 1-trimethylsilyloxycyclopentene-1 (5f)
(234 mg, 1.5 mmol). The reaction mixture was kept at ꢀ30 ꢁC
overnight. Further work-up of the reaction mixture and the
isolation of the target compound were carried out as described
in the typical experimental procedure in the main text. Product
13 was obtained as a mixture of syn/anti isomers (498 mg, 88%,
dark brownish oil, Rf 0.28 (SiO2, ethyl acetate/hexane, 1:10), syn/
anti¼12:1, the ratio was determined by comparison of 1H NMR
signal intensity). Stereochemical assignment was accomplished
using two-dimensional NMR technique and ROESY experiment.
In order to enrich the sample with a minor isomer the latter
was treated with dioxane/HCl complex in CH2Cl2 solution at
ꢀ30 ꢁC. Under these conditions the mixture underwent epi-
merisation to give the ratio of isomers 2:1 with the pre-
dominance of syn-isomer.
Compound 15-syn: 1H NMR (300 MHz, CDCl3): 1.48 (m, 1H), 1.61
(m, 2H), 1.87 (m, 1H), 2.00 (m, 2H), 2.23 (m, 1H), 2.37 (m, 1H), 2.88
(m, 1H), 2.94 (dd, J1¼8.5, J2¼13.4, 1H), 3.31 (dd, J1¼5.5, J2¼13.4, 1H),
3.43 (m, 1H), 5.91 (s, 1H), 7.20 and 7.23 (both d, J¼8.6, 2H each). 13C
NMR (75 MHz, CDCl3): 24.9, 27.3, 29.6, 38.8, 41.3, 42.2, 53.5, 75.1,
96.1, 129.2, 131.2, 132.7, 134.1, 199.5, 210.6.
Compound 15-anti: 1H NMR (300 MHz, CDCl3): 1.63 (m, 3H),
1.92 (m, 1H), 2.00 (m, 2H), 2.28 (m, 1H), 2.40 (m, 1H), 2.71 (m, 1H),
2.88 (m, 1H), 3.24 (dd, J1¼5.5, J2¼12.8, 1H), 3.57 (m, 1H), 6.12 (s, 1H),
7.20 and 7.27 (both d, J¼8.6, 2H each). 13C NMR (75 MHz, CDCl3):
Compound 13 (syn/anti): 1H NMR (300 MHz, CDCl3): 1.81 (m, 2H
in all), 2.10 (m, 2H in all), 2.18 (dd, syn-, J1¼19.0, J2¼8.3,1H), 2.31 (m,
anti-, 2H), 2.40 (dd, syn-, J1¼19.0, J2¼7.5, 1H), 2.49 and 2.84 (both m,

V.V. Tumanov et al. / Tetrahedron 66 (2010) 2156–2161
2161
25.1, 27.5, 30.1, 38.1, 40.1, 42.3, 55.8, 76.4, 97.6, 129.1, 130.7, 132.6,
References and notes
134.2, 199.5, 210.4.
1. (a) Nicholas, K. M. Acc. Chem. Res. 1987, 20, 207; (b) Mueller, T. J. J. Eur. J. Org.
Chem. 2001, 2021.
Compound 150 (syn/anti): 90% from 15, Rf 0.31 (SiO2, ethyl ace-
tate/hexane, 1:10). Elemental analysis calcd (%) for C16H17ClOS: C,
65.63; H, 5.85. Found (%): C, 65.86; H, 6.02.
2. Schreiber, S. L.; Klimas, M. T.; Sammakia, T. J. Am. Chem. Soc. 1987, 109, 5749.
3. (a) Mikaelyan, G. S.; Gybin, A. S.; Smit, W. A. Izv. Akad. Nauk USSR 1985, 2277;
(b) Gybin, A. S.; Smit, W. A.; Caple, R.; Veretenov, A. L.; Shashkov, A. S.; Vor-
ontsova, L. G.; Kurella, M. G.; Chertkov, V. S.; Karapetyan, A. A.; Kosnikov, A. Y.;
Alexanyan, M. S.; Lindeman, S. V.; Panov, V. N.; Maleev, A. V.; Struchkov, Y. T.;
Sharpe, S. M. J. Am. Chem. Soc. 1992, 114, 5555.
4. Mayr, H.; Kuhn, O.; Schlierf, C.; Ofial, A. R. Tetrahedron 2000, 56, 4219.
5. Tumanov, V. V.; Smit, W. A. Phosphorus, Sulfur Silicon Relat. Elem. 2005, 180, 1279.
6. Mayr, H.; Bug, T.; Gotta, M. F.; Hering, N.; Irrgang, B.; Janker, B.; Kempf, B.; Loos,
R.; Ofial, A. R.; Remennikov, G.; Schimmel, H. J. Am. Chem. Soc. 2001, 123, 9500.
7. It is noteworthy that the ZnCl2/Et2O catalyst (prepared according to Mayr, H.;
Striepe, W. J. Org. Chem. 1985, 50, 2995 ), in contrast to the rest of the Lewis
acids, could be used in catalytic amounts (10–15 mol %.). However, its use in the
reactions with isopropenylacetylenic complex 1b turned out to be inefficient
due to the formation of voluminous precipitate, which was insoluble at low
temperature (up to ꢀ30 ꢁC). The attempts to run the reaction at higher tem-
perature failed.
8. Smit, W. A.; Caple, R.; Smolyakova, I. P. Chem. Rev. 1994, 94, 2359.
9. Varghese, V.; Saha, M.; Nicholas, K. M. Org. Synth., CV 8, 460.
10. Vizniovsky, C. S.; Green, J. R.; Breen, T. L.; Dalacu, A. V. J. Org. Chem. 1995, 60,
7496.
11. At present it is premature to discuss the details of the mechanism and the
stereoselectivity pattern of the reaction, especially in view of the observed
dependence of the syn/anti ratio on the nature of the Lewis acid (see Table 2).
12. Blanco-Urgoiti, J.; An˜orbe, L.; Pe´rez-Serrano, L.; Domı´nguez, G.; Pe´rez-Castells, J.
Chem. Soc. Rev. 2004, 33, 32.
3.3.11. DCHC complex of 2-[2-methyl-1-(4-chlorophenylthio)but-3-
yn-2-yl]cyclohexanone (16). Following the procedure described for
6, the DCHC complex 1b (352 mg, 1.0 mmol) and trimethylsilyloxy-
cyclohexene-1 (5g) (255 mg, 1.5 mmol) were converted into the
mixture of syn/anti isomers of 16 (517 mg, 87%, dark brownish oil, Rf
0.34 (SiO2, ethyl acetate/hexane, 1:10), syn/anti¼2.5:1, the ratio was
determined by comparison of 1H NMR signal intensity).
Compound 16 (syn/anti): 1H NMR (250 MHz, CDCl3): 1.22 and
1.41 (both s, syn- and anti-, 3H in all), 1.49–2.18 (m, 6H in all), 2.21–
2.53 (m, 2H in all), 2.83 (m, 1H in all), 3.19 and 3.52 (both d, anti-,
J¼15.0, 1H each), 3.32 and 3.76 (both d, syn-, J¼14.0, 1H each), 6.13
and 6.16 (both s, 1H in all), 7.24 and 7.35 (both d, syn-, J¼8.8, 2H
each), 7.27 (s, syn-, 4H).
Compound 160 (syn/anti): 93% from 16, Rf 0.33 (SiO2, ethyl ace-
tate/hexane, 1:10). 1H NMR (250 MHz, CDCl3): 1.34 and 1.40 (both s,
anti- and syn-, 3H in all), 1.49–1.75 (m, 3H in all), 1.84–2.08 (m, 2H
in all), 2.15 and 2.17 (both s, syn- and anti-, 1H in all), 2.10–2.42 (m,
3H in all), 2.60 and 2.75 (both m, 1H in all), 3.23 and 3.52 (both d,
syn-, J¼12.6, 1H each), 3.21 and 3.61 (both d, anti-, J¼12.9, 1H each),
7.18 and 7.28 (both d, syn-, J¼8.8, 2H each), 7.19 and 7.31 (both d,
anti-, J¼8.5, 2H each).
13. Sokolov, D. V.; Litvinenko, G. S.; Isin, Zh. I. Izv. Akad. Nauk Kaz. SSR, Ser. Khim.
1959, 2, 68.
14. Schegolev, A. A.; Smit, W. A.; Mikaelyan, G. S.; Gybin, A. S.; YuKalyan, B.; Krimer,
M. Z.; Caple, R. Izv. Akad. Nauk SSSR, Ser. Khim. 1984, 2571; [ Bull. Acad. Sci., USSR,
Div. Chem. 1984, 33, 2355 (Engl. Transl)].
15. Harpp, D. N.; Friedlander, B. T.; Smith, R. A. Synthesis 1979, 3, 181.
16. Ainsworth, C.; Chen, F.; Kuo, Y. N. J. Organomet. Chem. 1972, 46, 59.
17. Cazeau, P.; Duboudin, F.; Moulines, F.; Babot, Os.; Dunogues, J. Tetrahedron 1987,
43, 2075.
13C NMR (75 MHz, CDCl3): 21.4, 24.1, 24.5, 24.7, 27.1, 27.3, 28.4,
28.7, 29.1, 29.7, 42.1, 42.4, 42.5, 43.2, 53.7, 55.4, 69.8, 70.0, 75.6, 76.0,
76.3, 76.4, 127.8, 127.9, 129.9, 130.1, 209.8. Elemental analysis calcd
(%) for C17H19ClOS: C, 66.54; H, 6.24. Found (%): C, 66.72; H, 6.45.
18. Hagen, G.; Mayr, H. J. Am. Chem. Soc. 1991, 113, 4954.
19. Klusener, P. A. A.; Kulik, W.; Brandsma, L. J. Org. Chem. 1987, 52, 5261.
20. Klusener, P. A. A.; Hommes, H. H.; Verkruijsse, H. D.; Brandsma, L. J. Chem. Soc.,
Chem. Commun. 1985, 1677.
21. It is also to be emphasized that the described work-up procedure was found to
be instrumental in order to obtain reproducibly good yields of the products
(even on the multi-gram scale). Otherwise a substantial decomposition may
occur obviously due to instability of the crude reaction products.
Acknowledgements
Financial support RFBR (project No. 06-03-33016) is gratefully
acknowledged.