Hydroalumination of thioacetylenes: A versatile generation and reactions of α-aluminate sulfides intermediates

Article abstract of DOI:10.1080/00397910802369497

Hydroalumination of thioacetylenes using DIBAL-H and lithium di-(isobutyl)-n-(butyl)-aluminate hydride (Zweifel's reagent), followed by addition of water, furnished exclusively the (Z)- and (E)-vinyl sulfides, respectively. The regio- and stereochemistry

Full text of DOI:10.1080/00397910802369497

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Hydroalumination of
Thioacetylenes: A Versatile
Generation and Reactions
of α-Aluminate Sulfides
Intermediates
P. G. Guerrero Jr. a , M. J. Dabdoub b , F. A. Marques
c , C. L. Wosch c , A. C. M. Baroni d & A. G. Ferreira
e
a Laboratory of Organic Synthesis and Natural
Products, State University of Sao Paulo/UNESP ,
Registro/SP , Brazil
b Laboratory of Organochalcogenes Compounds,
Department of Chemistry, University of Sao Paulo/
USP , Ribeirao Preto/SP , Brazil
c Laboratory of Chemical Ecology and Synthesis of
Natural Products, Department of Chemistry, Parana
Federal University/UFPR , Curitiba/PR , Brazil
d Department of Pharmacy and Biochemistry , Mato
Grosso do Sul Federal University/UFMS , Campo
Grande/MS , Brazil
e Laboratory of Nuclear Magnetic Resonance,
Federal University of Sao Carlos/UFSCar , Sao
Carlos/SP , Brazil
Published online: 07 Nov 2008.

To cite this article: P. G. Guerrero Jr. , M. J. Dabdoub , F. A. Marques , C. L. Wosch ,
A. C. M. Baroni & A. G. Ferreira (2008) Hydroalumination of Thioacetylenes: A
Versatile Generation and Reactions of α-Aluminate Sulfides Intermediates, Synthetic
Communications: An International Journal for Rapid Communication of Synthetic
Organic Chemistry, 38:24, 4379-4394, DOI: 10.1080/00397910802369497
To link to this article: http://dx.doi.org/10.1080/00397910802369497
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Synthetic Communications1, 38: 4379–4394, 2008
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910802369497
Hydroalumination of Thioacetylenes: A Versatile
Generation and Reactions of a-Aluminate
Sulfides Intermediates
P. G. Guerrero Jr.,1 M. J. Dabdoub,2 F. A. Marques,3
C. L. Wosch,3 A. C. M. Baroni,4 and A. G. Ferreira5
1Laboratory of Organic Synthesis and Natural Products, State University
of Sao Paulo=UNESP, Registro=SP, Brazil
2Laboratory of Organochalcogenes Compounds, Department of
Chemistry, University of Sao Paulo=USP, Ribeirao Preto=SP, Brazil
3Laboratory of Chemical Ecology and Synthesis of Natural Products,
Department of Chemistry, Parana Federal University=UFPR,
Curitiba=PR, Brazil
4Department of Pharmacy and Biochemistry, Mato Grosso do Sul Federal
University=UFMS, Campo Grande=MS, Brazil
5Laboratory of Nuclear Magnetic Resonance, Federal University of Sao
Carlos=UFSCar, Sao Carlos=SP, Brazil
Abstract: Hydroalumination of thioacetylenes using DIBAL-H and lithium
di-(isobutyl)-n-(butyl)-aluminate hydride (Zweifel’s reagent), followed by addition
of water, furnished exclusively the (Z)- and (E)-vinyl sulfides, respectively. The
regio- and stereochemistry of the intermediates generated, (Z)- and (E)-phenylthio
vinyl alanates, were determined by capture with iodine, which afforded the corres-
ponding (E)- and (Z)-1-iodo-1-phenylthio-2-organoyl ethenes. Reactions of the
(E)-iodo(thio)ketene acetals with n-BuLi followed by addition of hexanal afforded
the (Z)-phenylthio allylic alcohol, while the (Z)-iodo(thio)ketene acetals under simi-
lar reactions conditions gave the (E)-phenylthio allylic alcohol exclusively.
Keywords: Hydroalumination, phenylthio allylic alcohol, regiochemistry,
thio(iodo)ketene acetals, vinyl alanates, vinyl sulfides
Received November 22, 2007.
Address correspondence to P. G. Guerrero Jr., Laboratory of Organic
Synthesis and Natural Products, State University of Sao Paulo=UNESP,
Registro=SP, Brazil. E-mail: pali@registro.unesp.br
4379

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P. G. Guerrero Jr. et al.
INTRODUCTION
Among the organochalcogene species, vinyl sulfides have attracted
interest because they can be used as important intermediates in organic
synthesis.[1] These compounds have been used in the preparation of sub-
stituted olefines by a cross-coupling reaction with Grignard reagents,[2,3]
as well as in the synthesis of bioactive molecules.[4] The vinyl sulfide
moiety is found in many natural products with interesting biological
properties.[5] Considering the application of vinyl sulfides[6] in organic
synthesis, few methods described obtaining (Z)- and (E)-vinyl sulfides
derivatives with high stereoselectivity.[1,3,6b]
Moreover, a-halo vinyl sulfides have emerged as interesting intermedi-
ates, which are used to prepare a wide range of polyfunctionalized olefines
via a cross-coupling reaction catalyzed by transition metals.[7] However,
very few articles[7,8] described their preparation, and a general method to
synthesize (Z)- and (E)-a-halo vinyl sulfides with total control of regio-
and stereoselectivity has not yet been reported to the best of our knowledge.
RESULTS AND DISCUSSION
Here we describe the first synthesis of (Z)- and (E)-vinyl sulfides and
the corresponding (Z)- and (E)-iodo(thio)ketene acetals with high regio-
and stereoselectivity, applying as the key step the hydroalumination of
thioacetylenes.
The addition of diisobutylaluminum hydride (DIBAL-H) to the triple
bonds of thioacetylenes 1a–f followed by n-BuLi at 0 ꢀC afforded the (Z)-
phenylthio vinyl alanates 2a–f intermediates, which then were treated with
water to give exclusively the (Z)-phenylthio alkenes 3a-f (Scheme 1,
Table 1). Synthesis of isomers with the opposite stereochemistry, (E)-vinyl
sulfides 4a–f, was carried out employing lithium di-(isobutyl)-n-(butyl)
aluminate hydride (Zweifel’s reagent).[9] This interesting ‘‘ate’’ complex was
generated in situ by the reaction of n-BuLi (1.0 equiv.) and DIBAL-H
(1.0 equiv.) in tetrahydrofuran (THF) at 0 ꢀC, which was inserted in an
anti-fashion into thioacetylenes 1a–f leading to the formation of the
(E)-phenylthio vinyl alanates 5a–f, These intermediates were trapped with
water, furnishing exclusively the (E)-vinyl sulfides 4a–f (Scheme 1, Table 1).
The stereochemistry of the (Z)- and (E)-vinyl sulfides was determined
1
by H NMR experiments, considering the coupling constant value of
the vinylic hydrogen, in the ranges of 10.0–10.5 Hz and 14.5–15.0 Hz,
respectively.
Vinyl compounds containing two heteroatoms attached to the
same sp2 carbon such as telluroketene acetals,[10] telluro(seleno)ketene

Hydroalumination of Thioacetylenes
4381
Scheme 1. Hydroalumination of thioacetylenes.
acetals,[11] and seleno(halo)ketene acetals[12] have previously been
prepared and are used as versatile intermediates in organic synthesis.
Within the context of our strong interest in exploring a convenient
access to telluro(thio)ketene acetals with high regio- and stereoselectivity,
we developed the syn and anti-hydroalumination of thioacetylenes.[13]
However, the capture of the (E)-phenylthio vinyl alanate intermediate
with C4H9TeBr led to a stereoisomeric mixture of the (Z)- and (E)-
telluro(thio)ketene acetals.[13] These results, combined with the total
retention of configuration involving the capture of phenylthio alanates
2 and 5 with water (Scheme 1), prompted us to study the chemical reac-
tivity of these intermediates with other electrophiles.
In this way, the capture of the intermediates phenylthio vinyl
alanates 2a–f and 5a–f with iodine furnished, respectively, the (E)- and
(Z)-1-iodo-1-phenylthio-2-organoyl ethenes 6a–f and 7a–f, exclusively
and in good yields (Scheme 1).
Trisubstituted olefins, calcogeno(thio)ketene acetals and calcogeno-
(halo)ketene acetals, are important reagents and intermediates, which
can be applied to the formation of carbon–carbon bonds.[14]
We have previously reported the Te=Li exchange using telluro(thio)-
ketene acetals and subsequent reaction with aldehyde.[13] However, a
stereoisomeric mixture of the phenylthio allylic alcohols was obtained
when the reaction was performed with (E)-telluro(thio)ketene acetals.[13]
Now, we describe our preliminary results to demonstrate the synthetic
utility of (Z)- and (E)-iodo(thio)ketene acetals. The reaction of the

Table 1. Synthesis of vinyl sulfides and iodo(ketene) acetals
Reaction
time
Reaction
time
Thioacetylene
(min.)a
Productb
Yieldc
94
(min.)d
Productb
Yieldc
80
50
60
80
78
45
93
79
60
79
81

30
93
40
74
75
74
70
75
60
70
75
40
69
65
45
(Continued )

Table . Continued
Reaction
time
(min.)a
Reaction
time
Thioacetylene
Productb
Yieldc
65
(min.)d
Productb
Yieldc
60
60
50
70
67
60
55
65
aFormation of (Z)-vinyl alanates 2a–f intermediates.
bFully characterized by NMR, NOESY, MS.
cIsolated yields of the products purified by flash chromatography on silica gel.
dFormation of (E)-vinyl alanates 5a–f intermediates.

Hydroalumination of Thioacetylenes
4385
Scheme 2. Generation of (Z)- and (E)-a-lithiated vinyl sulfides.
isomerically pure (E)- and (Z)-1-iodo-1-thiophenyl-1-hexene 6b and 7b
(1.0 equiv.) with n-BuLi (1.1 equiv.) at ꢁ78ꢀC afforded the corresponding
(Z)- and (E)-a-lithiated vinyl sulfides 8 and 9. These intermediates were
trapped with hexanal (1.2 equiv.), furnishing the (Z)- and (E)-6-phenylthio-
5-dodecen-7-ol 10 and 11, respectively, with total retention of configuration
and good yields (Scheme 2). Direct condensation of phenylthio vinyl
alanates 2 and 5 intermediates with hexanal did not occur. Thus, it was
necessary to convert these intermediates into the iodine derivatives and to
effect the I=Li exchange before carrying out the reaction with the aldehyde.
In conclusion, we have developed new and efficient methodologies to
afford (Z)- and (E)-vinyl sulfides exclusively by the hydroalumination of
thioacetylenes using DIBAL-H and Zweifel’s reagent as the key step. By
using iodine instead of water as the electrophiles, we successfully
prepared the corresponding (E)- and (Z)-iodo(thio)ketene acetals with
total regio- and stereo-control. The I=Li exchange reaction involving
the isomerically pure (Z)- and (E)-iodo(thio)ketene acetals, described
here for the first time, allowed us to obtain (E)- and (Z)-phenylthioallylic
alcohols with total retention of stereochemistry.
EXPERIMENTAL
General Procedure for the Preparation of (Z)-Vinyl Sulfides
A solution of thioacetylene (1.0 mmol) in hexanes (2.0 mL) was added to
a flask containing a solution of DIBAL-H (2.0 mL, 2.0 mmol, 1.0 M in
hexanes) in hexanes (10 mL) under N2 at room temperature, and the
mixture was stirred under reflux (reaction time shown in Table 1). The

4386
P. G. Guerrero Jr. et al.
solution was cooled to 0 ꢀC, and then n-BuLi (1.53 mL, 2.0 mmol, 1.3 M
in hexanes) was added dropwise. Stirring continued for 30 min. After this
time, the mixture reached the room temperature, and water (5.0 mL) was
transferred to the flask via syringe. The products were extracted with ethyl
acetate (100 mL); the organic phase was washed with brine (3 ꢂ 50 mL)
and dried over anhydrous MgSO4. After filtration, the solvent was
removed under reduced pressure. The residue was purified by flash chro-
matography on silica gel (230–400 mesh) using hexane as mobile phase in
all cases, to give the corresponding (Z)-vinyl sulfides as yellow oil.
Data
(Z)-1-Phenylthio-1-pentene 3a
1
Yield: 94% (0.16 g). H NMR (80 MHz) (d in CDCl3) 0.9 (t, J ¼ 7.5 Hz,
3H), 1.4 (m, 2H), 2.2 (dt, J ¼ 9.0 Hz, J ¼ 7.5 Hz, 2H), 6.0 (dt, J ¼ 9.0 Hz,
J ¼ 7.5 Hz, 1H), 6.4 (d, J ¼ 10.0 Hz, 1H), 7.1–7.5 (m, 5H); 13C NMR
(20 MHz) (d in CDCl3) 12.3, 22.0, 30.1, 125.5, 126.5, 128.5, 129.7,
135.0, 135.9, 138.7, 138.9. Anal. calc. for C11H14S: C, 74.10; H, 7.81.
Found: C, 73.91; H, 7.65.
(Z)-1-Phenylthio-1-hexene 3b
Yield: 93% (0.18g). 1H NMR (80 MHz) (d in CDCl3) 1.0 (t, J ¼ 7.5 Hz, 3H),
1.1–1.5 (m, 4H), 2.3 (dt, J¼ 9.0 Hz, J ¼ 7.5 Hz, 2H), 5.8 (dt, J¼ 9.0 Hz, 1H),
6.3 (d, J¼ 10.0 Hz, 1H), 7.1–7.4 (m, 5H); 13C NMR (20 MHz) (d in CDCl3)
12.4, 22.2, 29.1, 30.2, 125.3, 126.4, 128.7, 129.8, 135.3, 135.7, 138.6, 138.9.
Anal. calc. for C12H16S: C, 75.11; H, 8.38. Found: C, 75.13; H, 8.45.
(Z)-1-Phenylthio-2-phenyl Ethene 3c
Yield: 93% (0.19 g). 1H NMR (80 MHz) (d in CDCl3) 6.4 (d, J ¼ 10.0 Hz,
1H), 6.6 (d, J ¼ 10.0 Hz, 1H), 7.5 (m, 10H); 13C NMR (20 MHz) (d in
CDCl3) 124.3, 124.5, 125.0, 125.5, 126.4, 126.8, 128.5, 128.7, 129.6,
130.4, 131.3, 132.5, 135.8, 138.9. Anal. calc. for C14H12S: C, 79.22; H,
5.65. Found: C, 78.82; H, 5.43.
(Z)-1-Phenylthio-2-cyclohexenyl Ethene 3d
Yield: 74% (0.16 g). 1H NMR (80 MHz) (d in CDCl3) 1.5–2.1 (m, 8H), 5.7
(m, 1H), 6.1 (d, J ¼ 10.0 Hz, 1H), 6.3 (d, J ¼ 10.0 Hz, 1H), 7.2 (m, 5H);
13C NMR (20 MHz) (d in CDCl3) 21.5, 22.3, 23.1, 24.5, 128.5, 128.7,

Hydroalumination of Thioacetylenes
4387
129.3, 130.4, 131.5, 135.1, 135.8, 138.5, 139.4, 140.2. Anal. calc. for
C14H16S: C, 77.72; H, 7.42. Found: C, 77.73; H, 7.25.
(Z)-1-Phenylthio-3-tetrahydropyranyl-1-propene 3e
Yield: 75% (0.18g). 1H NMR (300MHz) (d in CDCl3) 1.65 (br, THP methy-
lenes), 3.5 (d, J ¼ 7.5 Hz, 2H), 6.0 (dt, J ¼ 10.5 Hz, J¼ 7.5 Hz, 1H), 6.4
(d, J¼ 10.5 Hz, 1H), 7.3 (m, 5H); 13C NMR (75 MHz) (d in CDCl3) 10.6,
13.4, 21.8, 30.9, 58.6, 73.6, 126.3, 126.7, 127.3, 128.9, 132.3, 134.7, 139.6,
140.2. Anal. calc. for C14H18SO2: C, 67.20; H, 7.20. Found: C, 67.00; H, 7.40.
(Z)-1-Phenylthio-3-methyl-1,3-butadiene 3f
Yield: 70% (0.12 g). 1H NMR (300 MHz) (d in CDCl3) 0.9 (t, J ¼ 7.5 Hz,
3H), 5.1 (q, J ¼ 1.0 Hz, 1H), 5.2 (s, 1H), 6.6 (d, J ¼ 10.0 Hz, 1H), 6.8 (d,
J ¼ 10.0 Hz, 1H), 7.3 (m, 5H); 13C NMR (75 MHz) (d in CDCl3) 13.4,
103.1, 112.3, 126.5, 127.6, 128.6, 132.4, 128.3, 138.3, 139.4, 145.8. Anal.
calc. for C11H12S: C, 75.00; H 6.91. Found: C, 74.81; H, 6.74.
General Procedure for the Preparation of (E)-Iodo(thio)ketene Acetals
A solution of thioacetylene (1.0 mmol) in hexanes (2.0 mL) was added to
a flask containing a solution of DIBAL-H (2.0 mL, 2.0 mmol, 1.0 M in
hexanes) in hexanes (10 mL) under N2 at room temperature, and the mix-
ture was stirred under reflux (reaction time shown in Table 1). The solu-
tion was cooled to 0 ꢀC. Then n-BuLi (1.53 mL, 2.0 mmol, 1.3 M in
hexanes) was added dropwise, and stirring continued for 30 min. After
this time, the mixture reached the room temperature and a solution of
iodine [1.01 g, 4.0 mmol in THF (5.0 mL)] was transferred to the flask
via syringe. The products were extracted with ethyl acetate (100 mL);
the organic phase was washed with brine (3 ꢂ 50 mL) and dried over
anhydrous MgSO4. After filtration, the solvent was removed under
reduced pressure. The residue was purified by flash chromatography on
silica gel (230–400 mesh) using hexane as mobile phase in all cases to give
the corresponding (E)-iodo(thio)ketene acetals as yellow oil.
Data
(E)-1-Iodo-1-phenylthio-1-pentene 6a
1
Yield: 80% (0.24 g). H NMR (300 MHz) (d in CDCl3) 0.9 (t, J ¼ 7.5 Hz,
3H), 1.4 (sext, J ¼ 7.5 Hz, 2H), 2.3 (q, J ¼ 7.5 Hz, 2H), 6.9 (t, J ¼ 7.5 Hz,

4388
P. G. Guerrero Jr. et al.
1H), 7.1–7.5 (m, 5H); 13C NMR (75 MHz) (d in CDCl3) 13.7, 21.3, 39.7,
86.7, 127.3, 129.1, 129.9, 129.9, 132.4, 135.5, 152.9. MS m=z (%) 304
(19.83), 177 (100.0), 149 (10.13), 121 (49.98), 71 (52.10), 67 (45.77). Anal.
calc. for C11H13SI: C, 43.43; H, 4.23. Found: C, 43.00; H, 4.32.
(E)-1-Iodo-1-phenylthio-1-hexene 6b
1
Yield: 79% (0.25 g). H NMR (300 MHz) (d in CDCl3) 0.9 (t, J ¼ 7.5 Hz,
3H), 1.3–1.5 (m, 4H), 2.2 (q, J ¼ 7.5 Hz, 2H), 6.9 (t, J ¼ 7.5 Hz, 1H), 7.1–
7.6 (m, 5H); 13C NMR (75 MHz) 13.9, 22.3, 30.0, 37.5, 86.4, 127.1, 127.2,
127.4, 129.0, 129.8, 135.5, 151.9. MS m=z (%) 318 (9.54), 191 (25.33), 149
(46.83), 116 (28.13), 81 (100.0), 51 (2.52). Anal. calc. for C12H15SI: C,
45.26; H 4.75. Found: C, 45.63; H, 4.54.
(E)-1-Iodo-1-phenylthio-2-phenyl Ethene 6c
Yield: 75% (0.25 g). 1H NMR (300 MHz) (d in CDCl3) 7.1–7.2 (m, 11H);
13C NMR (75 MHz) 86.5, 127.1, 127.2, 127.4, 127.7, 129.0, 129.3, 129.8,
129.9, 135.5, 135.8, 152.6. MS m=z (%) 338 (23.76), 211 (30.44), 134
(100.0), 102 (56.7), 77 (12.3). Anal. calc. for C14H11SI: C, 49.76; H,
3.25. Found: C, 49.52; H, 3.12.
(E)-1-Iodo-1-phenylthio-2-cyclohexenyl Ethene 6d
1
Yield: 70% (0.24 g). H NMR (300 MHz) (d in CDCl3) 1.5–2.1 (m, 8H),
5.8 (m, 1H), 6.8 (s, 1H), 7.1–7.6 (m, 5H); 13C NMR (75 MHz) (d in
CDCl3) 21.6, 23.1, 23.4, 24.5, 87.4, 128.5, 128.7, 129.5, 131.4, 132.5,
135.1, 135.8, 138.5, 151.3. MS m=z (%) 342 (54.34), 215 (34.54), 106
(5.67), 71 (23.6). Anal. calc. for C14H15SI: C, 49.12; H, 4.34. Found: C,
48.87; H, 4.54.

Hydroalumination of Thioacetylenes
4389
(E)-1-Iodo-1-phenylthio-3-tetrahydropyranyl-1-propene 6e
1
Yield: 65% (0.24 g). H NMR (300 MHz) (d in CDCl3) 1.65 (br, THP
methylenes), 3.5 (d, J ¼ 7.5 Hz, 2H), 6.9 (t, J ¼ 7.5 Hz, 1H), 7.1–7.5 (m,
5H); 13C NMR (75 MHz) (d in CDCl3) 10.6, 13.4, 21.8, 32.9, 58.6,
75.6, 87.7, 126.3, 126.7, 127.3, 128.9, 132.3, 139.6, 151.2. MS m=z (%)
376 (6.78), 249 (13.43), 172 (100.0), 140 (6.78), 77 (45.5). Anal. calc. for
C14H17SIO2: C, 44.61; H, 4.54. Found: C, 44.2; H, 4.34.
(E)-1-Iodo-1-phenylthio-3-methyl-1,3-butadiene 6f
1
Yield: 60% (0.18 g). H NMR (300 MHz) (d in CDCl3) 0.9 (t, J ¼ 7.5 Hz,
3H), 5.2 (q, J ¼ 1.0 Hz, 1H), 5.3 (s, 1H), 6.8 (s, 1H), 7.2–7.4 (m, 5H); 13C
NMR (75 MHz) (d in CDCl3) 13.5, 86.9, 103.1, 126.5, 128.6, 132.4,
128.31, 138.3, 139.4, 140.4, 151.8. MS m=z (%) 302 (6.76), 175 (14.83),
98 (100.0), 83 (21.23), 77 (34.87). Anal. calc. for C11H11SI: C, 43.76; H,
3.65. Found: C, 44.00; H, 3.52.
General Procedure for (E)-Vinyl Sulfides
A solution of n-BuLi (1.53 mL, 2.0 mmol, 1.3 M in hexanes) was added
dropwise to a flask containing a solution of DIBAL-H (2.0 mL,
2.0 mmol, 1.0 M in hexanes) in THF (10 mL) at 0 ꢀC under N2, and the
mixture was stirred for 30 min. Then, a solution of thioacetylene (1.0 mmol)
in THF (2.0 mL) was added, and the mixture was stirred under reflux
(reaction time shown in Table 1). After this time, the mixture reached
the room temperature, and water (5.0 mL) was transferred to the flask
via syringe. It was stirred, and the product was extracted with ethyl
acetate (100 mL). The organic phase was washed with brine (3 ꢂ 50 mL)
and dried over anhydrous MgSO4. After filtration, the solvent was
removed under reduced pressure, and the crude product was purified
by flash chromatography on silica gel (230–400 mesh) using hexane as
mobile phase in all cases, giving the (E)-vinyl sulfides as yellow oil.
Data
(E)-1-Phenylthio-1-pentene 4a
Yield: 80% (0.14 g) 1H NMR (80 MHz) (d in CDCl3) 0.9 (t, J ¼ 7.5 Hz, 3H),
1.5 (m, 2H), 2.2 (dt, J ¼ 7.5 Hz, 2H), 6.1 (dt, J ¼ 15.0 Hz, J ¼ 7.5 Hz, 1H),
6.5 (d, J ¼ 15.0 Hz, 1H), 7.1–7.4 (m, 5H); 13C NMR (20 MHz) (d in CDCl3)

4390
P. G. Guerrero Jr. et al.
12.4, 22.1, 31.3, 125.3, 126.5, 128.5, 129.3, 135.3, 135.9, 138.7, 138.5. Anal.
calc. for C11H14S: C, 74.10; H, 7.81. Found: C, 73.61; H, 7.34.
(E)-1-Phenylthio-1-hexene 4b
1
Yield: 79% (0.15 g). H NMR (80 MHz) (d in CDCl3) 1.0 (t, J ¼ 7.5 Hz,
3H), 1.1–1.6 (m, 4H), 2.4 (dt, J ¼ 7.5 Hz, 2H), 5.3 (dt, J ¼ 15.0 Hz,
J ¼ 7.5 Hz, 1H), 6.4 (d, J ¼ 15.0 Hz, 1H), 7.2 (m, 5H); 13C NMR
(20 MHz) (d in CDCl3) 12.4, 22.5, 29.1, 30.3, 125.3, 126.4, 128.7, 129.8,
135.2, 135.7, 138.6, 138.6. Anal. calc. for C12H16S: C, 75.11; H, 8.38.
Found: C, 75.54; H, 8.98.
(E)-1-Phenylthio-2-phenyl Ethene 4c
Yield: 75% (0.16 g). 1H NMR (80 MHz) (d in CDCl3) 6.4 (d, J ¼ 15.0 Hz,
1H), 6.6 (d, J ¼ 15.0 Hz, 1H), 7.5 (m, 10H); 13C NMR (20 MHz) (d in
CDCl3) 124.3, 124.5, 125.0, 125.5, 126.4, 126.8, 128.5, 128.5, 129.6,
130.4, 131.9, 132.5, 135.8, 139.3. Anal. calc. for C14H12S: C, 79.22; H,
5.65. Found: C, 78.98; H, 5.23.
(E)-1-Phenylthio-2-cyclohexenyl Ethene 4d
Yield: 75% (0.16 g). 1H NMR (80 MHz) (d in CDCl3) 1.5–2.1 (m, 8H), 5.7
(m, 1H), 6.2 (d, J ¼ 14.5 Hz, 1H), 6.3 (d, J ¼ 14.5 Hz, 1H), 7.3 (m, 5H);
13C NMR (20 MHz) (d in CDCl3) 21.5, 22.3, 23.1, 24.5, 129.1, 128.7,
129.3, 130.4, 131.3, 135.1, 135.5, 138.5, 139.4, 142.2. Anal. calc. for
C14H16S: C, 77.72; H, 7.42. Found: C, 77.32; H, 7.71.
(E)-1-Phenylthio-3-tetrahydropyranyl-1-propene 4e
Yield: 65% (0.16 g). 1H NMR (300 MHz) (d in CDCl3) 1.62 (br, THP methy-
lenes), 3.5 (d, J ¼ 7.5 Hz, 2H), 6.2 (dt, J ¼ 14.3Hz, J ¼ 7.5 Hz, 1H), 6.5
(d, J ¼ 14.3 Hz, 1H), 7.3 (m, 5H); 13C NMR (75 MHz) (d in CDCl3) 10.6,
13.4, 21.8, 30.9, 58.6, 74.6, 126.3, 126.7, 127.3, 128.9, 132.3, 134.7, 139.6,
142.2. Anal. calc. for C14H18SO2: C, 67.20; H, 7.20. Found: C, 67.51; H, 7.05.
(E)-1-Phenylthio-3-methyl-1,3-butadiene 4f
1
Yield 67% (0.11 g). H NMR (300 MHz) (d in CDCl3) 0.9 (t, J ¼ 7.5 Hz,
3H), 5.2 (q, J ¼ 1.0 Hz, 1H), 5.3 (s, 1H), 6.6 (d, J ¼ 15.0 Hz, 1H), 6.89 (d,
J ¼ 15.0 Hz, 1H), 7.3 (m, 5H); 13C NMR (75 MHz) (d in CDCl3) 13.5,

Hydroalumination of Thioacetylenes
4391
103.2, 112.31, 126.5, 127.6, 129.3, 131.2, 128.31, 138.3, 139.4, 146.1. Anal.
calc. for C11H12S: C, 75.00; H, 6.91. Found: C, 75.32; H, 6.91.
General Procedure for (Z)-Iodo(ketene)acetals
A solution of n-BuLi (1.53 mL, 2.0 mmol, 1.3 M in hexanes) was added
dropwise to a flask containing a solution of DIBAL-H (2.0 mL,
2.0 mmol, 1.0 M in hexanes) in THF (10 mL) at 0 ꢀC under N2 and the
mixture was stirred for 30 min. Then, a solution of thioacetylene
(1.0 mmol) in THF (2.0 mL) was added, and the mixture was stirred
under reflux (reaction time shown in Table 1). After this time, the mixture
reached room temperature, and a solution of iodine [1.01 g, 4.0 mmol in
THF (5.0 mL)] was transferred to the flask via syringe. It was stirred, and
the product was extracted with ethyl acetate (100 mL). The organic phase
was washed with brine (3 ꢂ 50 mL) and dried over anhydrous MgSO4.
After filtration, the solvent was removed under reduced pressure, and
the crude product was purified by chromatography flash on silica gel
(230–400 mesh) using hexane as mobile phase in all cases, giving the
(Z)-iodo(thio)ketene acetals as yellow oil.
Data
(Z)-1-Phenylthio-1-iodo-1-pentene 7a
1
Yield: 78% (0.23 g). H NMR (300 MHz) (d in CDCl3) 0.9 (t, J ¼ 7.5 Hz,
3H), 1.5 (sext, J ¼ 7.5 Hz, 2H), 2.2 (q, J ¼ 7.5 Hz, 2H), 6.3 (t, J ¼ 7.5 Hz,
1H), 7.2–7.4 (m, 5H); 13C NMR (75 MHz) (d in CDCl3) 13.7, 21.3, 39.7,
91.2, 127.3, 127.4, 129.2, 129.8, 129.9, 135.5, 148.4. MS m=z (%) 304
(19.37), 177 (100.0), 143 (24.08), 135 (30.34), 71 (27.17), 67 (31.26). Anal.
calc. for C11H13SI: C, 43.43; H 4.23. Found: C, 43.72; H, 4.12.
(Z)-1-Iodo-1-phenylthio-1-hexene 7b

4392
P. G. Guerrero Jr. et al.
1
Yield: 81% (0.26 g). H NMR (300 MHz) (d in CDCl3) 0.9 (t, J ¼ 7.5 Hz,
3H), 1.3–1.5 (m, 4H), 2.2 (q, J ¼ 7.5 Hz, 2H), 6.3 (t, J ¼ 7.5 Hz, 1H), 7.2–
7.4 (m, 5H); 13C NMR (75 MHz) (d in CDCl3) 13.9, 22.2, 30.0, 37.5, 91.0,
127.1, 127.2, 127.4, 129.0, 129.8, 135.5, 148.6. MS m=z (%) 318 (7.62),
250 (12.6), 218 (31.83), 191 (13.27), 149 (20.17), 110 (100.0), 81 (25.30),
32 (14.09). Anal. calc. for C12H15SI: C, 45.26; H 4.75. Found C, 44.91;
H, 4.62.
(Z)-1-Iodo-1-phenylthio-2-phenyl Ethene 7c
Yield: 70% (0.23 g). 1H NMR (300 MHz) (d in CDCl3) 6.9 (s, 1H), 7.1–7.2
(m, 10H); 13C NMR (75 MHz) (d in CDCl3) 90.1, 127.2, 127.4, 127.4,
127.9, 129.3, 129.5, 129.8, 129.9, 135.7, 135.8, 148.9. MS m=z (%) 338
(4.62), 211 (45.76), 134 (100.0), 102 (3.45), 77 (5.76). Anal. calc. for
C14H11SI: C, 49.76; H, 3.25. Found: C, 49.52; H, 3.55.
(Z)-1-Iodo-1-phenylthio-2-cyclohexenyl Ethene 7d
Yield: 69% (0.23 g). 1H NMR (300 MHz) (d in CDCl3) 1.5–2.1 (m, 8H), 5.8
(m, 1H), 6.2 (s, 1H), 7.1–7.6 (m, 5H); 13C NMR (75 MHz) (d in CDCl3)
21.9, 23.3, 23.6, 24.5, 91.4, 128.7, 128.9, 129.5, 131.4, 132.5, 135.1, 138.5,
139.4, 148.3. MS m=z (%) 342 (34.56), 215 (23.45), 138 (100.0), 106
(6.54). Anal. calc. for C14H15SI: C, 49.12; H, 4.34. Found: C, 49.32; H, 4.4.
(Z)-1-Iodo-1-phenylthio-3-tetrahydropyranyl 1-Propene 7e
1
Yield: 60% (0.22 g). H NMR (300 MHz) (d in CDCl3) 1.62 (br, THP
methylenes), 3.3 (d, J ¼ 7.5 Hz, 2H), 6.2 (t, J ¼ 7.5 Hz, 1H), 7.2–7.6
(m, 5H); 13C NMR (75 MHz) (d in CDCl3) 10.7, 13.5, 21.8, 32.9, 58.6,
75.6, 92.1, 126.3, 126.7, 127.5, 129.2, 132.3, 139.6, 148.1. MS m=z (%)
376 (5.98), 249 (7.78), 172 (100.0), 140 (3.45), 52 (32.5). Anal. calc. for
C14H17SIO2: C, 44.61; H, 4.54. Found: C, 44.8; H, 4.12.
(Z)-1-Iodo-1-phenylthio-3-methyl-1,3-butadiene 7f
1
Yield: 65% (0.19 g). H NMR (300 MHz) (d in CDCl3) 0.9 (t, J ¼ 7.5 Hz,
3H), 5.2 (q, J ¼ 1.0 Hz, 1H), 5.3 (s, 1H), 6.2 (s, 1H), 7.2–7.4 (m, 5H); 13C
NMR (75 MHz) (d in CDCl3) 13.5, 91.9, 104.1, 126.8, 128.8, 132.4, 128.3,
138.3, 139.4, 140.4, 149.4. MS m=z (%) 302 (4.56), 175 (100.0), 98 (7.65),
77 (7.65), 66 (23.76) Anal. calc. for C11H11SI: C, 43.76; H, 3.65. Found:
C, 43.32; H, 3.32.

Hydroalumination of Thioacetylenes
ACKNOWLEDGMENT
4393
The authors thank Fundac¸a˜o de Amparo a Pesquisa do Estado de Sao
Paulo (FAPESP) and Fundac¸a˜o para o Desenvolvimento da UNESP
(FUNDUNESP) for financial support and Dr. Janet W. Reid (JWR
Associates) for assistance in revising the manuscript.
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