Umpolung of carbon-sulfur bonds. Novel synthesis of substituted allenes from propargylic dithioacetals

Article abstract of DOI:10.1021/jo991032b

Umpolung of the carbon-sulfur bonds can be achieved by treatment of propargylic dithioacetals 1 with organocuprates. The organocopper intermediates 3 gave the corresponding allenyl thioethers 4 upon protonolysis. When alkyl halides were used, propargylic thioethers 5 were obtained exclusively. Transmetalation of organocopper intermediates 3 with ZnBr₂ followed by Pd(PPh₃)₄-catalyzed coupling with vinylic or aryl halides afforded the corresponding allenyl thioethers 4. Either 4 or 5 reacted with Grignard reagents in the presence of NiCl₂(dppf) to yield the corresponding allenes 9 or 10, respectively. The overall reaction can be considered to use 1 as allene-1,3-zwitterion synthons. The relative reactivities of a propargylic ether versus a propargylic dithioacetal toward an organocopper reagent were compared. The sulfur moiety apparently has higher reactivity toward the copper reagent.

Full text of DOI:10.1021/jo991032b

8582
J . Org. Chem. 1999, 64, 8582-8587
Um p olu n g of Ca r bon -Su lfu r Bon d s. Novel Syn th esis of
Su bstitu ted Allen es fr om P r op a r gylic Dith ioa ceta ls
Hsian-Rong Tseng, Chin-Fa Lee, Lian-Ming Yang, and Tien-Yau Luh*
Department of Chemistry, National Taiwan University, Taipei, Taiwan 106
Received J une 28, 1999
Umpolung of the carbon-sulfur bonds can be achieved by treatment of propargylic dithioacetals 1
with organocuprates. The organocopper intermediates 3 gave the corresponding allenyl thioethers
4 upon protonolysis. When alkyl halides were used, propargylic thioethers 5 were obtained
exclusively. Transmetalation of organocopper intermediates 3 with ZnBr2 followed by Pd(PPh3)4-
catalyzed coupling with vinylic or aryl halides afforded the corresponding allenyl thioethers 4. Either
4 or 5 reacted with Grignard reagents in the presence of NiCl2(dppf) to yield the corresponding
allenes 9 or 10, respectively. The overall reaction can be considered to use 1 as allene-1,3-zwitterion
synthons. The relative reactivities of a propargylic ether versus a propargylic dithioacetal toward
an organocopper reagent were compared. The sulfur moiety apparently has higher reactivity toward
the copper reagent.
Sch em e 1
Carbon and sulfur have similar electronegativities;
therefore, the carbon-sulfur bond is ambiphilic. Accord-
ingly, the carbon end of a thioether linkage can serve
either as an electrophilic center or as a carbanionic
leaving group (Scheme 1). Numerous reactions are known
to employ the sulfide leaving group in organic synthesis.
For example, the conversion of a carbon-sulfur bond to
a carbon-carbon bond can be achieved by the nickel-
catalyzed cross coupling reactions of organosulfur com-
pounds with Grignard reagents.1-3 Umpolung of a carbon-
sulfur bond to generate a carbanionic leaving group from
the corresponding thioether is rare.4 In general, a stabi-
lized anionic species is essential for such heterolytic
cleavage reaction. Desulfurization of an R-thioalkoxycar-
bonyl compound can be achieved upon treatment with a
thioalkoxide anion.4a Benzylic dithioacetals react chemose-
lectively with organolithium reagents leading to the
formation of the corresponding sulfur-stabilized carban-
ions (eq 1).4b
react readily with organocopper reagents to give the
corresponding allenyl ethers.6 The extension of this
reaction to sulfur analogues, however, has not been
explored.7 Copper is thiophilic, so the complexation of
the organocopper reagent with the sulfur moiety might
occur readily. As such, the transfer of an alkyl nucleo-
phile from the organocopper reagent to the sulfur atom
of the dithioacetal group might generate intermediate 3
(eq 3). Similar to that described in eq 1, this organome-
tallic anionic species 3 is stabilized by the remaining
thioether moiety and by the triple bond. As part of our
continuing interest in the synthetic applications of the
dithioacetal functionality, we herewith report an unprec-
edented organocopper-induced C-S bond cleavage reac-
tion of propargylic dithioacetals followed by treatment
with an electrophile leading to the corresponding thio-
ethers 4 or 5.7
(1) (a) Okamura, H.; Miura, M.; Takei, H. Tetrahedron Lett. 1979,
19, 43. (b) Wenkert, E.; Ferreira, T. W.; Michelotti, E. L. J . Chem. Soc.,
Chem. Commun. 1979, 637.
(2) For reviews, see: (a) Naso, F. Pure Appl. Chem. 1988, 60, 79.
(b) Fiandanese, V. Pure Appl. Chem. 1990, 62, 1987. (c) Luh, T.-Y.;
Ni, Z.-J . Synthesis 1990, 89.
(3) For reviews, see: (a) Luh, T.-Y. Acc. Chem. Res. 1991, 24, 257.
(b) Luh, T.-Y.; Leung, M.-K. In Advances in the Use of Synthons in
Organic Chemistry; Dondoni, A., Ed.; J AI: London, 1995; Vol 2, p 129.
(c) Luh, T.-Y. Pure Appl. Chem. 1996, 68, 105.
We recently disclosed that propargylic dithioacetal 1
can serve as an allene-1,3-dication synthon 2. Thus,
treatment of 1 with the Grignard reagent in the presence
of a nickel catalyst (eq 2) results in replacing the two
carbon-sulfur bonds by two carbon-carbon bonds.2,5 The
(4) (a) Gassman, P. G.; Gilbert, D. P.; Luh, T.-Y. J . Org. Chem. 1977,
42, 1340. (b) Krief, A.; Kenda, B.; Barbeaux, P. Tetrahedron Lett. 1991,
32, 2509.
(5) Tseng, H.-R.; Luh, T.-Y. J . Org. Chem. 1996, 61, 8685.
(6) (a) Normant, J . F.; Alexakis, A. J . Organomet. Chem. 1973, 57,
C99. (b) Alexakis, A.; Mangeney, P.; Normant, J . F. Tetrahedron Lett.
1985, 26, 4197. (c) Alexakis, A.; Mangeney, P.; Ghribi, A.; Marek, I.;
Sedrani, R.; Normant, J . F. Pure Appl. Chem. 1988, 60, 49. (d) Alexakis,
A.; Mangeney, P. Tetrahedron Asymmetry 1990, 1, 477. (e) Marek, I.;
Mangeney, P.; Alexakis, A.; Normant, J . F. Tetrahedron Lett. 1986,
27, 5499. (f) Alexakis, A.; Marek, I.; Mangeney, P.; Normant, J . F. J .
Am. Chem. Soc. 1990, 112, 8042.
reaction would be more versatile if the two carbon-sulfur
bonds in 1 could be sequentially substituted by different
moieties. It is well-documented that propargylic acetals
(7) Preliminary communication: Tseng, H.-R.; Luh, T.-Y. J . Org.
Chem. 1997, 62, 4568.
10.1021/jo991032b CCC: $18.00 © 1999 American Chemical Society
Published on Web 10/21/1999

Umpolung of Carbon-Sulfur Bonds
J . Org. Chem., Vol. 64, No. 23, 1999 8583
Ta ble 1. Rea ction of 1 w ith R32Cu Li F ollow ed by
Tr ea tm en t w ith Selected Electr op h ile
product
entry substrate
R1
Ph
R2
R3
E
X
(%yield)
MeO 4a (88)
DO 4b (81)
MeO 4c (95)
MeO 4d (93)
1
2
3
4
5
6
7
8
9
1a
1b
Me tBu
tBu
H
D
H
H
Ph
Ph tBu
nBu
nBu TMS
Cl
4e (94)
nBu nBu3Sn Cl
4f (81)a
1c
1d
1e
nBu Me tBu
Ph nBu
nBu iPr nBu
H
H
H
MeO 4g (82)
MeO 4h (82)
MeO 4i (73)
H
Resu lts a n d Discu ssion
a
Compound 4f decomposes gradually upon standing and in
In the beginning of this investigation, benzylic dithio-
acetals 6 were employed to test the reactivity toward
organocopper reagents. Thus, each of 6a and 6b were
allowed to react with 0.6 equiv of Bu2CuLi at -78 °C
followed by quenching with methanol to give 7a and 7b
CDCl3 solution.
Ta ble 2. Rea ction of 1 w ith R32Cu Li F ollow ed by
t
Tr ea tm en t w ith Alk yl Ha lid e
product
(%yield)
entry substrate R1
R2 R3
E
X
in 95 and 90% yields, respectively (eq 4).
10
11
12
13
1a
Ph
Me tBu Me
I
5a (81)
5b (80)a
5c (89)
tBu CH2dCHCH2 Br
1b
1f
Ph
Ph nBu nBu
Br
TMS Me tBu
H
MeO 5d (94)
a
Crude yield. The product was used for the next reaction.
migrate under the reaction conditions.
An extension of this procedure to the reaction of 1a
under the same conditions gave the corresponding allenyl
thioether 4a (entry 1, Table 1). Deuterium incorporation
at allenyl carbon (C3) was observed when the organocop-
per intermediate was quenched with D2O (entry 2). As
can be seen from Table 1, a variety of electrophiles
ranging from proton (entries 1-4, 7-9), organosilyl
(entry 5) and tin (entry 6) reagents can be used to furnish
the reaction in good to excellent yields. Substituents in
the starting 1 can vary from hydrogen, alkyl, to aryl
groups.
As can be seen from Tables 1-3, a number of allenyl/
propargylic thioethers 4/5 can be easily obtained from
the reactions of 1 with organocopper reagents. Sequential
treatment of these thioethers with the Grignard reagent
in the presence of 5 mol % of NiCl2(dppf) resulted in a
convenient synthesis of substituted allenes 9 or 10 (eqs
7 and 8). Table 4 summarizes representative examples.
As expected,8 reduction of the C-S bond in 3c was
observed when i-PrMgBr was employed (entry 20). These
results demonstrate the first examples of using propar-
gylic dithioacetals as allene zwitterion synthons 12.
The reaction may proceed via intermediate 3a . It is
well documented that there is an equilibrium between
an allenyl organometallic intermediate 3a and a prop-
argylic species 3b. The corresponding 5, however, was
not obtained when these electrophiles were used.
When a soft alkyl halide electrophile was employed to
react with the organocopper intermediate 3, selective
carbon-carbon bond formation leading to a propargylic
thioether 5 was observed. Typical examples are outlined
in Table 2. It is noteworthy that neither 4 nor 5 reacted
further with the organocopper reagent under these
conditions. Interestingly, the protonolysis of the organo-
copper intermediate arisen from the reaction of 1f with
tBu2CuLi gave 5d . The steric bulkiness of the trimeth-
ylsilyl substituent presumably determines the chemose-
lectivity of the reaction.
As can be seen in Table 2, the reaction proceeds
successfully with carbon electrophiles having Csp3 hy-
bridization. The reaction would be more versatile if other
carbon electrophiles could also be employed. Transmeta-
lation of the organocopper intermediate with ZnBr2
followed by the palladium-catalyzed coupling reaction
gave the corresponding allenes 4 in good yield (eq 5).
Typical examples are tabulated in Table 3. Attempts
to synthesize the allyl-substituted allene by using
allyl bromide as an electrophile yielded the rearranged
triene (eq 6). Presumably, the allenyl double bond may

8584 J . Org. Chem., Vol. 64, No. 23, 1999
Tseng et al.
Ta ble 3. Rea ction of 1 w ith R32Cu Li F ollow ed by
Tr ea tm en t w ith Zn Br 2 a n d Th en Cou p lin g w ith
Electr op h ile u n d er P d Ca ta lyst
t
at -78 °C was added a pentane solution of BuLi (0.7 mL of
1.7 M solution, 1.2 mmol). The mixture was stirred at -78 °C
for 15 min to give a THF/pentane solution of tBu2CuLi which
was used directly for the next reaction. A THF/hexane solution
product
(%yield)
n
of Bu2CuLi (5.7 mL, 0.6 mmol) was prepared similarly.
entry substrate
R1
Ph
R2
R3
E
X
6,6-Dim eth yl-1,1-d ip h en yl-2,5-d ith ia h ep ta n e (7a ). Un-
der argon atmosphere, to a THF/pentane solution of tBu2CuLi
(5.7 mL, 0.6 mmol) at -78 °C was added dropwise 6a (258
mg, 1.0 mmol) in THF (5 mL) over a period of 10 min. The
mixture was stirred at -78 °C for 30 min, quenched with
methanol (0.3 mL), and passed through a short-path of neutral
alumina. The solvent was removed in vacuo to give the residue
which was chromatographed on silica gel (1% EtOAc in
hexane) to afford 6a as a colorless oil (301 mg, 95%): 1H NMR
(300 MHz, CDCl3) δ 1.23 (s, 9 H), 2.56-2.69 (m, 4 H), 5.22 (s,
1 H), 7.21 (t, J ) 7.2 Hz, 2 H), 7.30 (t, J ) 7.2 Hz, 4 H), 7.43
(d, J ) 7.2 Hz, 4 H); 13C NMR (75 MHz, CDCl3) δ 28.3, 30.9,
32.8, 42.5, 54.3, 127.2, 128.3, 128.5, 141.1; HRMS calcd for
C19H24S2: 316.1319, found: 316.1322.
6,6-Dim eth yl-1-ph en yl-2,5-dith iah eptan e (7b). In a man-
ner similar to that described for the reaction of 6a , 6b (182
mg, 1.00 mmol) was allowed to react with tBu2CuLi (5 mL,
0.6 mmol in THF/pentane) at -78 °C for 30 min to yield a
colorless oil 7b (163 mg, 90%): 1H NMR (300 MHz, CDCl3) δ
1.26 (s, 9 H), 2.55-2.68 (m, 4 H), 3.73 (s, 2 H), 7.20-7.32 (m,
5 H); 13C NMR (75 MHz, CDCl3) δ 28.4, 31.0, 31.7, 36.4, 42.5,
127.0, 128.5, 128.8, 138.2; HRMS calcd for C13H20S2: 240.1006,
found: 240.1017.
3,8,8-Tr im eth yl-1-p h en yl-4,7-d ith ia -1,2-n on a d ien e (4a ).
In a manner similar to that described for the reaction of 6a ,
tBu2CuLi (5.7 mL, 0.6 mmol in THF/pentane) was allowed to
react with 1a (220 mg, 1.0 mmol) in THF (5 mL) to give 4a as
a colorless oil (243 mg, 88%): bp 90 °C (0.05 mmHg); 1H
NMR (300 MHz, CDCl3) δ 1.18 (s, 9 H), 2.04 (d, J ) 3.0 Hz, 3
H), 2.67-2.79 (m, 4 H), 6.36 (q, J ) 3.0 Hz, 1 H), 7.15-7.30
(m, 5 H); 13C NMR (75 MHz, CDCl3) δ 19.6, 28.4, 30.9, 32.8,
42.6, 99.7, 101.9, 127.0, 127.3, 128.6, 134.6, 198.4; IR (NaCl,
neat) 1919 cm-1; HRMS calcd for C16H22S2: 278.1162, found:
278.1172.
14
15
16
17
1b
Ph nBu 4-MeC6H4
nBu tBuCO
I
4j (69)
Cl 4k (65)a
Br 4l (30)
nBu PhCtC
1c
nBu Me nBu 4-MeC6H4
I
4m (78)a
a
Crude yield. The product was used directly for the next
reaction.
When NiCl2(dppe) was employed as the catalyst in the
coupling reaction of 4a , the corresponding dimeric prod-
uct 11 was obtained in 52% yield (entry 25). The
stereochemistry of 11 was determined by the NOE
experiments. Dimerization of 9a was also achieved in
59% yield upon treatment with MeMgI in the presence
of NiCl2(dppe).
It is known that propargylic ether can readily undergo
an SN2′ reaction to give the corresponding allene.6 It is
highly intriguing to compare the reactivities of a prop-
argylic ether versus a propargylic dithioacetal upon
treatment with an organocopper reagent. Thus, 13 was
synthesized (eq 9) and allowed to react with nBu2CuLi
followed by the usual workup to give 15 in 91% yield (eq
10). Attempts to synthesize the higher cumulenes from
16 or 17 were unsuccessful and a mixture of unidentified
products was obtained.
t
A similar reaction of 1a (220 mg, 1.00 mmol) with Bu2CuLi
(5.0 mL, 0.6 mmol in THF/pentane) followed by quenching with
D2O (0.3 mL) to give 4b as a colorless oil (226 mg, 81%): 1H
NMR (300 MHz, CDCl3) δ 1.18 (s, 9 H), 2.03 (s, 3 H), 2.67-
2.79 (m, 4 H), 7.15-7.26 (m, 3 H), 7.28 (d, J ) 4.2 Hz, 2 H);
13C NMR (75 MHz, CDCl3) δ 19.6, 28.4, 30.9, 32.8, 42.5, 99.5
(t, J ) 24.3 Hz), 102.1, 127.0, 127.3, 128.6, 134.6, 198.3; HRMS
calcd for C16H21DS2: 279.1225, found: 279.1227.
8,8-Dim eth yl-1,3-diph en yl-4,7-dith ia-1,2-n on adien e (4c).
In a manner similar to that described for the reaction of 6a ,
tBu2CuLi (5.7 mL, 0.6 mmol in THF/pentane) at -78 °C was
allowed to react with 1b (282 mg, 1.00 mmol) in THF (5 mL)
to give 4c as a colorless oil (323 mg, 95%): 1H NMR (200 MHz,
CDCl3) δ 1.19 (s, 9 H), 2.70-2.95 (m, 4 H), 6.73 (s, 1 H), 7.21-
7.39 (m, 8 H), 7.54-7.60 (m, 2 H); 13C NMR (50 MHz, CDCl3)
δ 28.4, 30.9, 33.0, 42.6, 101.5, 108.2, 126.6, 127.3, 127.8, 128.1,
Con clu sion s
In summary, we have demonstrated for the first time
the use of propargylic dithioacetals as allene-1,3-zwit-
terion synthons 12. By employing this procedure, di-, and
tri- as well as tetrasubstituted allenes are synthesized
conveniently.
128.5, 128.9, 133.6, 134.2, 202.8; IR (NaCl, neat) 1948 cm-1
HRMS calcd for C16H22S2: 340.1319, found: 340.1320.
;
1,3-Dip h en yl-4,7-d ith ia -1,2-u n d eca d ien e (4d ). In a man-
ner similar to that described for the reaction of 6a , the reaction
of 1b (220 mg, 1.00 mmol) with nBu2CuLi (5.7 mL, 0.6 mmol
in THF/hexane) gave 4d as a colorless oil (316 mg, 93%): 1H
NMR (300 MHz, CDCl3) δ 0.82 (t, J ) 7.2 Hz, 3 H), 1.27 (sextet,
J ) 7.2 Hz, 2 H), 1.42 (quin, J ) 7.2 Hz, 2 H), 2.27-2.43 (m,
2 H), 2.63-2.80 (m, 2 H), 2.91 (t, J ) 7.2 Hz, 2 H), 6.73 (s, 1
H), 7.22-7.36 (m, 8 H), 7.54-7.57 (m, 2 H); 13C NMR (75 MHz,
CDCl3) δ 13.6, 21.0, 25.6, 31.7, 31.9, 32.8, 101.8, 108.3, 126.6,
127.2, 127.9, 128.2, 128.5, 128.9, 133.6, 134.2, 202.5; IR (NaCl,
neat) 1949 cm-1; HRMS calcd for C16H22S2: 340.1319, found:
340.1319.
1-(Tr im eth ylsilyl)-1,3-d ip h en yl-4,7-d ith ia -1,2-u n d eca -
d ien e (4e). In a manner similar to that described for the
reaction of 6a , the reaction of 1b (282 mg, 1.0 mmol) with
nBu2CuLi (5.7 mL, 0.6 mmol in THF/hexane) at -78 °C. The
mixture was stirred at -78 °C for 1.5 h, chlorotrimethylsilane
(0.2 mL, 1.5 mmol) was introduced, and the mixture was
Exp er im en ta l Section
P r ep a r a tion of Cu p r a te Rea gen ts. Under argon atmo-
sphere, to a slurry of CuI (114 mg, 0.60 mmol) in THF (5 mL)
(8) (a) Wenkert, E.; Hanna, J . M., J r.; Leftin, M. H.; Michelotti, E.
L.; Potts, K. T.; Usifer, D. J . Org. Chem. 1985, 50, 1125. (b) Wenkert,
E.; Ferreira, T. W. J . Chem. Soc., Chem. Commun. 1982, 840. (c) Trost,
B. M.; Lavoie A. C. J . Am. Chem. Soc. 1983, 105, 5075. (d) Trost, B.
M.; Ornstein, P. L. J . Org. Chem. 1982 47, 748. (e) Shen, G.-Y.; Tapia,
R.; Okamura, W. H. J . Am. Chem. Soc. 1987, 109, 7499. (f) Fabre, J .-
L.; J ulia, M. Tetrahedron Lett. 1983, 24, 4311. (g) Cuvigny, T.; Fabre,
J .-L.; Herve´ du Penhoat, C.; J ulia, M. Tetrahedron Lett. 1983, 24, 4319.
(h) Fabre, J .-L.; J ulia, M.; Verpeaux, J .-L. Bull. Soc. Chim. Fr. 1985,
772. (i) Capet, M, Cuvigny, T.; Herve´ du Penhoat, C.; J ulia, M.; Loomis,
G. Tetrahedron Lett. 1987, 28, 6273.

Umpolung of Carbon-Sulfur Bonds
J . Org. Chem., Vol. 64, No. 23, 1999 8585
Ta ble 4. NiCl2(L)-Ca ta lyzed Cr oss-Cou p lin g Rea ction s of 4 or 5 w ith Gr ign a r d Rea gen ts
product
(%yield)
entry
substrate
R1
R2
E
R4
L
18
19
20
21
22
23
24
25
4a
4g
4c
4m
5a
5b
5c
4a
Ph
Me
Me
Ph
Me
Me
Me
Ph
H
H
H
Me
Ph
iPr
Ph
dppf
dppf
dppe
dppe
dppe
dppe
dppe
dppe
9a (81)
9b (67)
9c (50)
9d (55)
10a (72)
10b (62)
10c (67)
11 (52)
nBu
Ph
nBu
Ph
Ph
Ph
Ph
4-MeC6H4
Me
H2CdCGCH2
Bu
H
TMSCH2
nBu
Ph
Me
Me
gradually warmed to room temperature and stirred for 1 h.
The mixture was taken up in pentane (20 mL) and passed
through a short basic alumina column. The solution was
evaporated in vacuo, and the residue was chromatographed
on basic alumina (1% EtOAc in hexane pretreated with
K2CO3) to give 4e (328 mg, 94%): 1H NMR (200 MHz, acetone-
d6) δ 0.32 (s, 9 H), 0.83 (t, J ) 7.1 Hz, 3 H), 1.20-1.50 (m, 4
H), 2.34-2.45 (m, 2 H), 2.63-2.80 (m, 2 H), 2.85-2.92 (m, 2
H), 7.20-7.42 (m, 8 H), 7.55-7.65 (m, 2 H); 13C NMR (300
MHz, CDCl3) δ -0.2, 13.6, 21.9, 31.7, 31.8, 32.0, 33.2, 99.4,
106.0, 126.1, 126.9, 127.1, 127.9, 128.5, 128.7, 134.7, 136.1,
207.3; IR (NaCl, neat) 1901 cm-1; HRMS calcd for C24H32S2Si:
412.1715, found: 412.1725.
1-(Tr ibu tylsta n n yl)-1,3-d ip h en yl-4,7-d ith ia -1,2-u n d ec-
a d ien e (4f). In a manner similar to that described for the
reaction of 4e, the reaction of 1b (282 mg, 1.0 mmol) with
nBu2CuLi (5.7 mL, 0.6 mmol in THF/hexane) at -78 °C.
Bu3SnCl (0.4 mL, 1.5 mmol) was introduced, and the mixture
was gradually warmed to room temperature and stirred for
an additional 6 h. Pentane (20 mL) was added, and the mixture
was passed through basic alumina. The solution was evapo-
rated in vacuo, and the residue was chromatographed on basic
alumina (hexane pretreated with K2CO3) to give 4f (510 mg,
81%): 1H NMR (200 MHz, CDCl3) δ 0.73-1.10 (m, 12 H),
1.15-1.70 (m, 22 H), 2.30-2.40 (m, 2 H), 2.60-3.00 (m, 4 H),
7.10-7.50 (m, 8 H), 7.55-7.65 (m, 2 H); IR (NaCl, neat) 1897
cm-1; HRMS (FAB) calcd for C33H50S2120Sn: 630.2376,
found: 630.2383. Compound 4f decomposes gradually upon
standing and in CDCl3 solution. No satisfactory 13C NMR was
obtained. Neverthelss, it did show absorption at δ 202.9
attrbuted to the Csp allenyl carbon. No signals due to alkyne
carbons (δ 80-95) were observed.
1.07 (d, J ) 6.7 Hz, 3 H), 1.08 (d, 6.7 Hz, 3 H), 1.28-1.44 (m,
6 H), 1.49-1.60 (m, 2 H), 1.96-2.05 (m, 2 H), 2.16-2.27 (m, 1
H), 2.51 (t, J ) 7.6 Hz, 2 H), 2.61-2.80 (m, 4 H), 5.43 (dt, J )
2.1 Hz, J ) 6.6 Hz, 1 H); 13C NMR (50 MHz, CDCl3) δ 13.6,
13.9, 21.9, 22.0, 22.2, 22.3, 29.4, 31.4, 31.7, 31.9, 32.4, 32.8,
98.8, 109.2, 195.7; IR (NaCl, neat) 1951 cm-1; HRMS calcd for
C
16H30S2 286.1789, found 286.1797.
3,3,8,8-Tetr a m eth yl-1-p h en yl-4,7-d ith ia -1-n on yn e (5a ).
To a THF/pentane solution of tBu2CuLi (11.4 mL, 1.2 mmol in
THF/pentane) at -78 °C was added dropwise 1a (440 mg, 2.00
mmol) in THF (10 mL) over a period of 15 min. The mixture
was stirred at -78 °C for 5 min. HMPA (0.33 mL, 2.0 mmol)
and MeI (0.19 mL, 3.0 mmol) were then added, and the
mixture was stirred at -78 °C for 30 min and then passed
through a short neutral alumina. The solvent was removed in
vacuo to give the residue which was distilled to give 5a as a
1
colorless oil (472 mg, 81%): bp 120 °C (0.05 mmHg), H NMR
(300 MHz, CDCl3) δ 1.27 (s, 9 H), 1.63 (s, 6 H), 2.78-3.03 (m,
4 H), 7.24-7.27 (m, 3 H), 7.34-7.41 (m, 2 H); 13C NMR (75
MHz, CDCl3) δ 19.6, 28.6, 30.9, 31.2, 39.2, 42.5, 82.4, 93.3,
126.5, 127.9, 128.1, 131.6; IR (NaCl, neat) 2201 cm-1; HRMS
calcd for C16H22S2: 292.1319, found: 292.1312.
3-Bu tyl-1,3-d ip h en yl-4,7-d ith ia -1-u n d ecyn e (5c). Under
argon atmosphere, a THF solution (5 mL) of nBu2CuLi
(prepared from 1.2 mmol of nBuLi and CuI (114 mg 0.6 mmol))
was added dropwise to a solution of 1b (282 mg, 1.0 mmol) in
THF (5 mL) at -78 °C and the mixture was stirred at -78 °C
for 0.5 h. HMPA (0.26 mL, 1.5 mmol) was introduced, and the
mixture was stirred for an additional 1 h. After 1-bromobutane
(0.16 mL, 1.5 mmol) was added, the mixture was allowed to
warm to room temperature and stirred overnight, taken up
in pentane (20 mL), and passed through basic alumina. The
solution was evaporated in vacuo, and the residue was
chromatographed on basic alumina (hexane pretreated with
K2CO3) to give 5c (353 mg, 89%): 1H NMR (200 MHz, CDCl3)
δ 0.82 (t, J ) 7.2 Hz, 3 H), 0.84 (t, J ) 7.0 Hz, 3 H), 1.10-1.65
(m, 8 H), 2.0-2.2 (m, 2 H), 2.35 (t, J ) 7.3, 2 H), 2.4-2.85 (m,
2 H) 7.2-7.45 (m, 6 H) 7.42-7.6 (m, 2 H) 7.65-7.8 (m, 2 H).;
13C NMR (100 MHz, CDCl3) δ 13.60, 13.88, 14.11, 21.91, 22.61,
27.76, 31.24, 31.62, 31.71, 43.30, 51.89, 87.17, 90.44, 123.04,
127.18, 127.28, 128.19, 128.28, 128.34, 131.67, 142.02.; HRMS
calcd for C25H32S2: 396.1945, found: 396.1942.
2,2,7-Tr im eth yl-3,6-d ith ia tr id eca -7,8-d ien e (4g). In a
manner similar to that described for the reaction of 6a , the
reaction of 1c (200 mg, 1.00 mmol) with tBu2CuLi (5.7 mL,
0.6 mmol in THF/pentane) gave 4g as a colorless oil (211 mg,
82%): bp 75 °C (0.05 mmHg) 1H NMR (200 MHz, CDCl3) δ
0.84 (t, J ) 7.2 Hz, 3 H), 1.22-1.39 (m, 13 H, embodied a
t
singlet at 1.28 due to the Bu group), 1.84 (d, J ) 2.8 Hz, 3 H),
1,92-1.99 (m, 2 H), 2.66-2.70 (m, 4 H), 5.31 (tq, J ) 7.2, 2.8
Hz); 13C NMR (50 MHz, CDCl3) δ 13.9, 20.1, 22.2, 28.2, 29.2,
31.0, 31.2, 32.7, 42.5, 96.8, 97.0, 197.5; IR (NaCl, neat) 1932
cm-1; HRMS calcd for C14H26S2: 258.1476, found: 258.1490.
3-P h en yl-4,7-d ith ia u n d eca -1,2-d ien e (4h ). In a manner
3,8,8-Tr im e t h yl-1-(t r im e t h ylsilyl)-4,7-d it h ia -1-n on -
yn e (5d ). In a manner similar to that described for the
reaction of 6a , 1f (216 mg, 1.00 mmol) was treated with
tBu2CuLi (5 mL, 0.6 mmol in THF/pentane) to give 5d as a
n
similar to that described for the reaction of 4a , Bu2CuLi (5.7
mL, 0.6 mmol in THF/hexane) at -78 °C was allowed to react
1
with 1d (206 mg, 1.00 mmol) in THF (5 mL) to give 4h as a
colorless oil (257 mg, 94%): bp 85 °C (0.05 mmHg); H NMR
1
colorless oil (216 mg, 82%): bp 65 °C (0.05 mmHg); H NMR
(300 MHz, CDCl3) δ 0.13 (s, 9 H), 1.30 (s, 9 H), 1.44 (d, J )
4.2 Hz, 3 H), 2.71-2.97 (m, 4 H), 3.67 (q, J ) 4.2 Hz); 13C
NMR (50 MHz, CDCl3) δ 0.0, 21.6, 28.6, 29.8, 31.1, 31.9, 42.6,
(300 MHz, CDCl3) δ 0.89 (t, J ) 7.3 Hz, 3 H), 1.36 (tq, J ) 7.3,
7.5 Hz, 2 H), 1.52 (tt, J ) 7.3, 7.5 Hz, 2 H), 2.49 (t, J ) 7.3 Hz,
2 H), 2.72-2.76 (m, 2 H), 2.86-2.89 (m, 2 H), 5.27 (s, 2 H),
7.23 (t, J ) 7.2 Hz, 1 H), 7.29-7.37 (m, 2 H), 7.53 (m, 2 H);
13C NMR (75 MHz, CDCl3) δ 13.6, 21.9, 31.5, 31.8, 31.9, 32.9,
87.6, 106.1; IR (NaCl, neat) 2165 cm-1; HRMS calcd for C13H26
SiS2: 274.1245, found: 274.1264.
-
1,3-Dip h en yl-1-(4-m eth ylp h en yl)-4,7-d ith ia u n d eca -1,2-
d ien e (4j). Under argon atmosphere, to a THF/hexane solution
of nBu2CuLi (5.7 mL, 0.6 mmol) at -78 °C was added dropwise
1b (282 mg, 1.00 mmol) in THF (5 mL) over a period of 15
min. The mixture was stirred at -78 °C for 5 min. THF
solution of ZnCl2 (1.0 mL, 1.0 mmol in THF) was then added,
the mixture was stirred at -78 °C for 30 min, and then a THF
solution of 4-iodotoluene (244 mg, 1.2 mmol) and Pd(PPh3)4
(57.5 mg, 0.05 mmol) was added at -78 °C. The mixture was
stirred at room temperature and then passed through a short-
81.0, 103.0, 126.7, 127.7, 128.5, 134.2, 206.3; IR (neat, cm-1
)
1935 (allene); HRMS calcd for C15H20S2: 264.1007, found:
264.1006.
7-(2-P r op yl)-8,11-d ith ia -5,6-p en ta d eca d ien e (4i). In a
manner similar to that described for the reaction of 6a , the
reaction of 1e (228 mg, 1.0 mmol) with nBu2CuLi (5.7 mL, 0.6
mmol in THF/hexane) followed by quenching with methanol
gave 4i as a colorless oil (210 mg, 73%): 1H NMR (300 MHz,
CDCl3) δ 0.88 (t, J ) 7.3 Hz, 3 H), 0.90 (t, J ) 7.3 Hz, 3 H),

8586 J . Org. Chem., Vol. 64, No. 23, 1999
Tseng et al.
path neutral alumina. The solvent was removed in vacuo to
give a pale yellow oil, which was chromatographed on basic
alumina (EtOAc/hexane ) 1/50) to give 4j as a colorless oil
(296 mg, 69%): 1H NMR (300 MHz, CDCl3) δ 0.89 (t, J ) 7.2
Hz, 3 H), 1.22-1.51 (m, 4 H), 2.32 (t, J ) 7.2 Hz, 3 H), 2.41 (s,
3 H), 2.60-2.68 (m, 2 H), 2.96-3.04 (m, 2 H), 7.22 (d, J ) 7.8
Hz, 2 H), 7.30-7.51 (m, 10 H), 7.68 (dt, J ) 6.6, 1.4 Hz); 13C
NMR (50 MHz, CDCl3) δ 13.5, 21.1, 21.8, 31.6, 31.8, 32.0, 32.7,
107.0, 116.4, 126.5, 127.8, 128.0, 128.2, 128.3, 128.4, 128.5,
129.2, 132.8, 134.5, 136.0, 137.7, 203.3; IR (NaCl, neat) 1908
cm-1; HRMS calcd for C28H30S2: 430.1789, found: 430.1794.
2,2-Dim eth yl-4,6-d ip h en yl-3-oxo-7,10-d ith ia tetr a d eca -
4,5-d ien e (4k ). In a manner similar to that described for
preparation of 4j, 1b (282 mg, 1.00 mmol) was allowed to react
with nBu2CuLi (5.7 mL, 0.6 mmol in THF/hexane) and then
added THF solution of ZnBr2 (1.0 mL, 1.0 mmol in THF) and
stirred at -78 °C, followed the THF solution (5 mL) of pivaloyl
chloride (0.15 mL, 1.2 mmol) and Pd(PPh3)4 (57.5 mg, 0.05
mmol). The mixture was stirred at room temperature for 12 h
to give 4k as yellow oil (274 mg, 65%): 1H NMR (300 MHz,
acetone-d6) δ 0.89 (t, J ) 7.2 Hz, 3 H), 1.18-1.45 (m, 13H,
embodied a singlet at 1.24 due to the tert-butyl group), 2.30-
2.44 (m, 2 H), 2.58-2.72 (m, 2 H), 2.91-3.00 (m, 2 H), 7.30-
7.48 (m, 8 H), 7.62-7.65 (m, 2 H); 13C NMR (75 MHz, acetone-
d6) δ 13.9, 22.4, 27.3, 32.0, 32.3, 32.5, 33.7, 46.1, 110.0, 113.5,
127.5, 128.3, 129.0, 129.5, 129.6, 129.8, 134.3, 134.4, 202.4,
206.2; IR (NaCl, neat) 1951 cm-1; HRMS calcd for C26H32OS2:
424.1895, found: 424.1901.
1,3,5-Tr ip h en yl-6,9-d ith ia tr id eca -3,4-d ien -1-yn e (4l). In
a manner similar to that described for the reaction of 4j, 1b
(282 mg, 1.00 mmol) was allowed to react with nBu2CuLi (5.7
mL, 0.6 mmol in THF/hexane), followed by the addition of a
THF solution of ZnBr2 (1.0 mL, 1.0 mmol in THF) and stirred
at -78 °C for 30 min. A THF solution (5 mL) of 1-bromo-2-
phenylacetylene (217 mg, 1.2 mmol) and Pd(PPh3)4 (57.5 mg,
0.05 mmol) was then added, the mixture was stirred at room
temperature for 12 h to give 4l as yellow oil (130 mg, 30%):
1H NMR (300 MHz, acetone-d6) δ 0.79 (t, J ) 7.2 Hz, 3 H),
1.20-1.32 (m, 2 H), 1.37-1.47 (m, 2 H), 2.40-2.50 (m, 2 H),
2.76-3.06 (m, 4 H), 7.36-7.51 (m, 9 H), 7.60-7.64 (m, 4 H),
7.74-7.77 (m, 2 H); 13C NMR (75 MHz, acetone-d6) δ 13.5, 21.9,
22.6, 31.5, 33.0, 38.7, 81.7, 95.1, 100.7, 110.3, 122.9, 126.4,
126.9, 128.1, 128.3, 128.6, 128.7, 128.8, 131.6, 132.3, 133.4,
207.5; IR (NaCl, neat) 1903, 2202 cm-1; HRMS calcd for
the presence of NiCl2(dppf) (34 mg, 0.05 mmol) to yield 9b (125
mg, 67%): 1H NMR (300 MHz, CDCl3) δ 0.92 (t, J ) 6.9 Hz, 3
H), 1.33-1.52 (m, 4 H), 2.07-2.17 (m, 5 H embodied a doublet
at 2.10 for Me group, J ) 3.0 Hz), 5.46 (tq, J ) 6.0, 3.0 Hz, 1
H), 7.20 (t, J ) 7.0 Hz, 1 H), 7.29-7.35 (m, 2 H), 7.41-7.45
(m, 2 H); 13C NMR (50 MHz, CDCl3) δ 13.9, 17.2, 22.3, 28.7,
31.4, 93.0, 100.2, 125.6, 126.2, 128.2, 137.8, 204.1; IR (NaCl,
neat) 1948 cm-1; HRMS calcd for C14H18: 186.1408, found:
186.1414.
1,3-Dip h en yl-1,2-p r op a d ien e (9c). In a manner similar
to that described for the reaction of 4a , crude 4c prepared
i
above was treated at room temperature with PrMgBr (2.0 mL
of 1.0 M solution, 2.0 mmol) in the presence of NiCl2(dppe)
(33 mg, 0.05 mmol) to yield 9c (96 mg, 50%): mp: 46-48 °C
(lit.9 49-51 °C).
2-P h en yl-4-(4-m eth ylp h en yl)-2,3-octa d ien e (9d ). In a
manner similar to that described for 5a , crude 4m was allowed
to react with a benzene/ether (9/1, 5 mL) solution of PhMgBr
(2.0 mmol) in the presence of NiCl2(dppe) (26 mg, 0.05 mmol)
under reflux for 12 h to yield 9d as a colorless oil (152 mg,
55%): 1H NMR (300 MHz, CDCl3) δ 0.97 (t, J ) 7.0 Hz, 3 H),
1.39-1.71 (m, 4 H), 2.26 (s, 3 H), 2.38 (s, 3 H), 2.60 (t, J ) 7.2
Hz, 2 H), 7.17 (d, J ) 8.0 Hz, 2 H), 7.23-7.41 (m, 5 H), 7.49-
7.53 (m, 2 H); 13C NMR (75 MHz, CDCl3) δ 14.0, 16.9, 21.1,
22.6, 30.0, 30.1, 103.4, 107.6, 125.6, 125.9, 126.5, 128.3, 129.1,
134.0, 136.3, 137.4, 205.3; IR (NaCl, neat) 1934 cm-1; HRMS
calcd for C21H24: 276.1878, found: 276.1884.
4-Met h yl-2-p h en yl-1-(t r im et h ylsilyl)-2,3-p en t a d ien e
(10a ). In a manner similar to that described for the reaction
of 4a , crude 5a prepared above was allowed to react with
TMSCH2MgCl (2.0 mL of 1 M solution, 2.0 mmol) to yield 10a
(164 mg, 72%): 1H NMR (200 MHz, CDCl3) δ 0.05 (s, 9 H),
1.80 (s, 3 H), 1.82 (s, 6 H), 7.13-7.45 (m, 5 H); 13C NMR (75
MHz, CDCl3) δ -1.2, 19.0, 20.6, 96.7, 100.3, 125.9, 126.2, 128.0,
139.6, 202.4; IR (NaCl, neat) 1949 cm-1; HRMS calcd for
C
13H18Si: 230.1491, found: 230.1488.
1-P h en yl-1-(tr im eth ylsilyl)-1,2-bu ta d ien e (10c). In a
manner similar to that described for the reaction of 4a , crude
5c prepared above was allowed to react with PhMgBr (2.0 mL
of 1 M solution, 2.0 mmol) to yield 10c (135 mg, 67%): 1H NMR
(200 MHz, CDCl3) δ 0.23 (s, 9 H), 1.73 (d, J ) 7.0, 3 H), 5.11
(q, J ) 7.0 Hz, 1 H), 7.12-7.33 (m, 5 H); 13C NMR (75 MHz,
CDCl3) δ -0.3, 13.4, 81.5, 99.6, 126.0, 127.6, 128.3, 138.1,
209.3; IR (NaCl, neat) 1927 cm-1; HRMS calcd for C13H18Si:
202.1179, found: 202.1177.
C
29H28S2: 440.1632, found: 440.1644.
7-Meth yl-5-(4-m eth ylp h en yl)-8,11-d ith ia p en ta d eca -5,6-
4-Meth yl-6-p h en yl-1,4,5-d eca tr ien e (10b). Under argon
atmosphere, to a THF/pentane solution of tBu2CuLi (11.4 mL,
1.2 mmol in THF/pentane) at -78 °C was added dropwise
propargyl dithiolane 1a (440 mg, 2.00 mmol) in THF (10 mL)
over a period of 15 min. The mixture was stirred at -78 °C
for 5 min, allyl bromide (0.24 mL, 3 mmol) was added, and
the mixture was stirred at -78 °C for 30 min. The mixture
was passed through a short-path neutral alumina. The solvent
was removed in vacuo to give a pale yellow oil 5b (251 mg,
80%): 1H NMR (200 MHz, CDCl3) δ 1.18 (s, 9 H), 2.04 (s, 3
H), 2.61-2.82 (m, 4 H), 3.25 (d, J ) 6.3 Hz, 2 H), 5.06-5.18
(m, 2 H), 5.87-6.07 (m, 1 H), 7.14-7.45 (m, 5 H). Crude 5b
was allowed to react with nBuMgBr (4.0 mL of 1M solution,
4.0 mmol) in the presence of NiCl2(dppf) (68 mg, 0.10 mmol)
in benzene (10 mL) at room temperature for 6 h to yield 10b
(279 mg, 62%): 1H NMR (200 MHz, CDCl3) δ 0.96 (t, J ) 7.2
Hz, 3 H), 1.34-1.60 (m, 4 H), 1.82 (s, 3 H), 2.43 (t, J ) 6.8 Hz,
2 H), 2.86 (d, J ) 6.8 Hz, 2 H), 5.04-5.18 (m, 2 H), 5.90 (ddt,
J ) 7.0, 10.0, 16.8 Hz, 1 H), 7.14-7.45 (m, 5 H); 13C NMR
(50 MHz, CDCl3) δ 14.0, 18.5, 22.5, 29.9, 30.2, 39.2, 101.0,
104.8, 115.9, 125.9, 126.1, 128.2, 136.0, 138.2, 201.7; IR (NaCl,
neat) 1951 cm-1; HRMS calcd for C13H18Si: 226.1722, found:
226.1719.
d ien e (4m ). In a manner similar to that described for the
reaction of 4j, 1c (200 mg, 1.00 mmol) was allowed to react
with nBu2CuLi (5.7 mL, 0.6 mmol in THF/hexane) and then
with ZnBr2 (1.0 mL, 1.0 mmol in THF), 4-iodotoluene (244 mg,
1.2 mmol), and Pd(PPh3)4 (57.5 mg, 0.05 mmol) in THF (5 mL)
to give 4m as yellow oil (269 mg, 78%): 1H NMR (300 MHz,
CDCl3) δ 0.82 (t, J ) 7.0 Hz, 3 H), 0.92 (t, J ) 7.1 Hz, 3 H),
1.24-1.60 (m, 8 H), 2.01 (s, 3 H), 2.27-2.33 (m, 5H, embodied
a singlet at 2.31 due to the methyl group), 2.45 (d, J ) 6.8 Hz,
2 H), 2.50-2.74 (m, 4 H), 7.06-7.28 (m, 5 H). The product was
used for the next reaction without further purification.
3-Meth yl-1-p h en yl-1,2-bu ta d ien e (9a ). An ether solution
of MeMgI (1.0 mL of 2.0 M solution, 2.0 mmol) was evacuated
to remove the ether solvent. Under argon atmosphere, a
benzene (5 mL) solution of 4a prepared above and NiCl2(dppf)
(34 mg, 0.05 mmol) were added and the mixture was refluxed
for 12 h, quenched with saturated NH4Cl (10 mL), and
extracted with ether (10 mL × 3). The organic layer was dried
(MgSO4), and the solvent was removed by distillation to give
a pale yellow oil, which was chromatographed on silica gel
(pentane) to give 9a as a colorless oil (116 mg, 81%)1: 1H NMR
(300 MHz, CDCl3) δ 1.86 (d, J ) 3 Hz, 6 H), 6.02 (septet, J )
3 Hz, 1 H), 7.16-7.34 (m, 5 H); 13C NMR (75 MHz, CDCl3) δ
20.2, 92.5, 99.1, 126.3, 126.6, 128.4, 136.0, 203.1; IR (NaCl,
neat) 1954 cm-1; HRMS calcd for C11H12: 144.0939, found:
144.0933.
1,4-Dip h en yl-2-(2-p r op yl)-3-(2-p r op en yl)-1,3-b u t a d i-
en e (11). In a manner similar to that described for the reaction
of 4a , crude 4a was allowed to react with MeMgI (1.0 mL of
2.0 M solution, 2.0 mmol) in the presence of NiCl2(dppe) (26
2-P h en yl-2,3-octa d ien e (9b). In a manner similar to that
described for the reaction of 4a , crude 4g prepared above was
treated with PhMgBr (2.0 mL of 1 M solution, 2.0 mmol) in
(9) Elsevier, C. J .; Vermeer, P. J . Org. Chem. 1985, 50, 3042.

Umpolung of Carbon-Sulfur Bonds
J . Org. Chem., Vol. 64, No. 23, 1999 8587
clohexyl)ethynyl]-1,3-dithiolane as a white solid (2.01 g,
mg, 0.05 mmol) under reflux for 12 h to yield 11 (75 mg,
52%): 1H NMR (300 MHz, CDCl3) δ 1.00 (d, J ) 6.8 Hz, 3 H,
6% NOE upon irradiation at δ 6.56), 1.08 (d, J ) 6.8 Hz, 3 H,
5% NOE upon irradiation at δ 6.56), 2.06 (s, 3 H, 9% NOE
upon irradiation at δ 6.68), 2.32 (doublet of septet, J ) 1.2,
6.8 Hz, 1 H, 3% NOE upon irradiation at δ 6.56), 4.94 (s, 1
H), 5.14 (s, 1 H), 6.56 (s, 1 H), 6.68 (s, 1H, 19% NOE upon
irradiation at δ 2.06), 7.11-7.25 (m, 6 H), 7.39 (d, J ) 7.2 Hz,
2 H), 7.50 (d, J ) 7.2 Hz, 2 H); 13C NMR (75 MHz, CDCl3) δ
21.1, 21.8, 22.1, 35.9, 116.7, 126.5, 126.6, 127.0, 128.0, 128.1,
128.7, 137.5, 137.9, 140.8, 143.5, 145.6; HRMS calcd for
83%): mp 72-75 °C; 1H NMR (200 MHz, CDCl3) δ 1.10-1.13
(m, 1 H), 1.35-1.75 (m, 7 H), 1.80-1.90 (m, 2 H), 1.97 (s, 3
H), 2.29 (s, 1 H), 3.40-3.57 (m, 4 H); 13C NMR (50 MHz, CDCl3)
δ 23.3, 25.1, 31.2, 39.9, 40.5, 54.2, 68.6, 86.3, 88.3; HRMS calcd
for C12H18OS2: 242.0799, found: 242.0799.
Under argon atmosphere, to a THF solution (80 mL) of the
alcohol prepared above (1.21 g, 5.0 mmol) at -78 °C was added
MeLi (3.5 mL, 5.5 mmol in ether). The mixture was stirred
for 30 min to which MeI (0.44 mL, 7.0 mmol) in DMSO (5 mL)
was added at -78 °C. The mixture was stirred at room
temperature for 6 h, quenched with saturated NH4Cl (10 mL),
and extracted with ether (20 mL × 3). The organic layer was
dried (MgSO4), and the solvent was removed in vacuo to give
the residue which was chromatographed on silica gel (EtOAc/
hexane ) 1/10) to give 13 as a white solid (1.16 g, 91%): mp:
C
22H24: 288.1878, found: 288.1870.
In a separate experiment treatment of 5a (144 mg, 1.00
mmol) in benzene (5 mL) with MeMgI (0.1 mL of 1.0 M
solution, 0.1 mmol) in the presence of NiCl2(dppe) (26 mg, 0.05
mmol) under reflux for 12 h yielded 11 (85 mg, 59%).
1
4,6-Dip h en yl-7,10-d ith ia tetr a d eca -1,3,5-tr ien e (8). In a
manner similar to that described for the preparation of 4j, 1b
(282 mg, 1.00 mmol) was allowed to react with nBu2CuLi (5.7
mL, 0.6 mmol in THF/hexane). A THF solution of ZnBr2 (1.0
mL, 1.0 mmol in THF) and stirred at -78 °C, followed by
treatment with allyl bromide (0.11 mL, 1.2 mmol) and Pd-
(PPh3)4 (57.5 mg, 0.05 mmol) in THF (5 mL). The mixture was
stirred at room temperature for 12 h to give 8 as a mixture of
stereoisomers (312 mg, 82%): 1H NMR (300 MHz, CDCl3) δ
0.86 (t, J ) 7.2 Hz, 6 H), 1.29-1.46 (m, 8 H), 2.25-2.34 (m, 4
H), 2.56-2.58 (m, 4 H), 2.67-2.71 (m, 4 H), 5.00 (d, J ) 9.8
Hz, 1 H), 5.07 (d, J ) 10.1 Hz, 1 H), 5.16 (d, J ) 16.1 Hz, 1 H),
5.18 (d, J ) 16.8 Hz, 1 H), 6.21-6.37 (m, 2 H, embodied a
doublet at 6.27 due to the olefinic proton), 6.57-6.77 (m, 2 H,
embodied a doublet at 6.75 due to the olefinic proton), 6.95-
7.32 (m, 22 H); 13C NMR (75 MHz, CDCl3) δ 13.5, 21.8, 31.55,
31.62, 31.69, 31.72, 31.8, 31.9, 32.0, 118.5, 118.6, 125.9, 126.6,
126.8, 127.1, 127.4, 127.5, 127.6, 127.8, 128.0, 129.0, 129.5,
129.6, 131.1, 133.8, 134.2, 137.1, 137.2, 137.9, 138.0, 139.7,
140.5; HRMS calcd for C24H28S2: 380.1632, found: 380.1635.
2-Met h yl-2-[2-(1-m et h oxycycloh exyl)et h yn yl]-1,3-d i-
th iola n e (13). Under argon atmosphere, to a THF solution
(8 mL) of 14 (1.44 g, 10 mmol) at -78 °C was treated with
nBuLi (6.32 mL, 11.0 mmol in hexane). The mixture was
stirred at -78 °C for 30 min to which cyclohexanone (1.30 mL,
10.0 mmol) was added. After stirring at room temperature for
30 min, the mixture was quenched with saturated NH4Cl (10
mL) and extracted with ether (30 mL × 3). The organic layer
was dried (MgSO4), and the solvent was removed in vacuo to
give a pale yellow oil, which was chromatographed on silica
gel (EtOAc/hexane ) 1/5) to give 2-methyl-2-[2-(1-hydroxycy-
51-53 °C; H NMR (200 MHz, CDCl3) δ 1.12-1.19 (m, 1 H),
1.36-1.68 (m, 7 H), 1.76-1.88 (m, 2 H), 1.98 (s, 3 H), 3.29 (s,
3 H), 3.37-3.53 (m, 4 H); 13C NMR (50 MHz, CDCl3) δ 22.9,
25.4, 31.2, 36.7, 40.4, 50.7, 54.3, 74.0, 83.7, 90.3; IR (KBr) 2222
cm-1; HRMS calcd for C13H20OS2: 256.0955, found: 256.0959.
4-Meth yl-1,1-p en ta m eth ylen e-5,8-d ith ia -1,2,3-d od eca -
tr ien e (15). Under argon atmosphere, to a THF/hexane
solution of nBu2CuLi (5.7 mL, 0.6 mmol in THF/pentane) at
-78 °C was added dropwise 13 (256 mg, 1.0 mmol) in THF (5
mL) over a period of 15 min. The mixture was stirred at -78
°C for 15 min, quenched with methanol (0.3 mL, 11.4 mmol)
and then passed through a short-path neutral alumina column.
The solvent was removed in vacuo to give 15 as colorless oil
(257 mg, 91%): 1H NMR (200 MHz, benzene-d6) δ 0.75 (t, J )
7.4 Hz, 3 H), 1.15-1.65 (m, 10 H), 2.00 (s, 3 H), 2.22-2.35 (m,
6 H), 2.68-2.76 (m, 2 H), 2.92-3.00 (m, 2 H); 13C NMR (75
MHz, benzene-d6) δ 13.9, 22.2, 22.8, 26.4, 28.0, 28.2, 32.1, 32.2,
33.4, 34.8, 35.3, 107.7, 115.1, 146.7, 154.5; IR (NaCl, neat) 2050
cm-1; HRMS calcd for C13H20OS2: 282.1476, found: 282.1479.
Ack n ow led gm en t. This work was supported by the
National Science Council of the Republic of China.
Su p p or tin g In for m a tion Ava ila ble: 1H NMR spectra of
4a -l, 5a , 5c, 5d , 7a , 7b, 8, 9a , 9b, 9d , 10a -c, 11, 13, and 15
and 13C NMR spectra of 4a -d , 4g-l, 5a , 5c, 5d , 7a , 7b, 8,
9a , 9b, 9d , 10a -c, 11, 13, and 15. This material is available
free of charge via the Internet at http://pubs.acs.org.
J O991032B