Synthesis of trisubstituted and tetrasubstituted alkenes via a manganate-induced migration-elimination process

Article abstract of DOI:10.1016/S0040-4020(01)01069-9

Preparation of alkenes via a manganate-induced alkylation-elimination sequence was investigated. The reaction of 2-alkoxy-1,1-dibromoalkanes with trialkylmanganates afforded disubstituted or trisubstituted alkenes. Treatment of 2-alkoxy-1,1,1-tribromoalkanes with trialkylmanganates provided trisubstituted or tetrasubstituted alkenes through bromine-metal exchange, transfer of two alkyl groups from manganese to carbon, and successive elimination of metal and the β-alkoxy moieties.

Full text of DOI:10.1016/S0040-4020(01)01069-9

TETRAHEDRON
Pergamon
Tetrahedron 57 92001) 10063±10069
Synthesis of trisubstituted and tetrasubstituted alkenes via a
manganate-induced migration±elimination process
Hirotada Kakiya, Hiroshi Shinokubo and Koichiro Oshimap
Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
Received 13 September 2001; accepted 25 October 2001
AbstractÐPreparation of alkenes via a manganate-induced alkylation±elimination sequence was investigated. The reaction of 2-alkoxy-
1,1-dibromoalkanes with trialkylmanganates afforded disubstituted or trisubstituted alkenes. Treatment of 2-alkoxy-1,1,1-tribromoalkanes
with trialkylmanganates provided trisubstituted or tetrasubstituted alkenes through bromine±metal exchange, transfer of two alkyl groups
from manganese to carbon, and successive elimination of metal and the b-alkoxy moieties. q 2001 Elsevier Science Ltd. All rights reserved.
1. Introduction
Grignard reagents or alkyllithiums,10,11 provided alkylated
alkenes or 9E)-alkenylsilanes in good yields, respectively.12
Then, we anticipated that the reaction of di- and tri-
bromoalkanes bearing a leaving group with trialkylmanga-
nates could be applied to prepare tri- and tetrasubstituted
alkenes according to Scheme 1. Bromine±manganese
exchange followed by 1,2-migration of an alkyl group and
sequential elimination of manganese and the leaving group
would afford the desired alkenes. Here, we wish to report
that treatment of these bromides with trialkylmanganates
provided the alkylated or dialkylated polysubstituted
alkenes in one-step.
Alkenes are useful building blocks in a number of synthetic
applications including epoxidation, hydroxylation,
dihydroxylation, haloetheri®cation, and so forth. Alkenes
with various substitution patterns are found in the structure
of numerous natural products and pharmaceutical agents.
Therefore, the stereoselective synthesis of polysubstituted
alkenes is a very important issue in synthetic chemistry.1 For
alkene synthesis, one can use the condensation-type reaction
of carbonyl compounds such as the Wittig reaction,2 or
related reactions.3,4 However, the condensation-type
reaction is not effective for the synthesis of tetrasubstituted
alkenes due to the steric demand of the products. The
McMurry coupling reaction is useful only to prepare cyclic
alkenes or symmetric alkenes, in which all substituents are
identical.5 The transition metal-catalyzed coupling reaction
using alkenyl halides or alkenyl metals as precursors is a
powerful means to access trisubstituted alkenes.6 However,
it is often dif®cult to prepare trialkyl-substituted alkenyl
halides or alkenyl metals regio- and stereoselectively.7
Consequently, the protocol is scarcely utilized for the
synthesis of tetrasubstituted alkenes.8,9
2. Results and discussion
We have reported that the reaction of 1,1-dibromo-2-9t-
butyldimethylsiloxy)-2-phenylethane 91a) with tributyl-
manganate afforded 1-phenyl-1-hexene 92) in only 38%
yield 9Scheme 2).12 After further investigation, we found
that the use of n-Bu3MnLi in place of n-Bu3MnMgBr
improved the yield of 2 up to 85% yield.
Table 1 shows the results of the reaction of various dibromo-
alkanes with manganates. Several comments are worth
noting. 91) The substituents on silicon had no signi®cant
in¯uence on the yield of the product 9entries 1 and 2).
We have reported that treatment of gem-dibromoalkanes or
trialkyl9dibromomethyl)silanes with trialkylmanganates,
derived from manganese9II) chloride and 3.0 equiv. of
Scheme 1.
Keywords: manganese and compounds; alkenes; halogens and compounds; migration.
Corresponding author. Tel.: 181-75753-5523; fax: 181-75753-4863; e-mail: oshima@fm1.kuic.kyoto-u.ac.jp
p
0040±4020/01/$ - see front matter q 2001 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020901)01069-9

10064
H. Kakiya et al. / Tetrahedron 57 ,2001) 10063±10069
Scheme 4.
Scheme 2.
Table 1. The reaction of dibromoalkanes with trialkylmanganate
Scheme 5.
Entry R1
R2
R3 MnMtl
Yield 9%)a E/Z
3
1
P
h
h
t-BuMSei2 91a) n-Bu3MnLi 85 92)
50/50
46/54
47/53
61/39
69/31
63/37
47/53
45/55
9trimethylsiloxy)ethane 911a) with n-Bu3MnLi resulted in
the incorporation of two butyl groups to afford 2-butyl-1-
phenyl-1-hexene 912) in 56% yield 9Scheme 5).
2
Ph
Ph
P
P
Ph
SiMe3 91b)
SiMe3 91b)
2P hC91Hc)
1d) H 9
SiMe3 91b)
n-Bu3MnLi 87 92)
n-Bu3MnLi 81 92)
n-Bu3MnLi 52 92)
n-Bu3MnLi 65 92)
3b
4
5b
6
h
Table 2 summarizes the double alkylation reaction of
various tribromoalkanes with manganates. Several issues
regarding the results in Table 2 merit comment.13 91) The
tribromo compound 11b with a t-butyldimethylsiloxy group
also provided 12 in almost same yield 9entry 1). 92) The use
of benzoate 11c decreased the yield of the product 12
slightly 9entry 2). 93) The reaction of the unprotected
alcohol 11d also provided the desired alkene 12 9entry 3).
94) The reaction of 11a with 2.2 equiv. of triallylmanganate,
which was prepared by mixing allylmagnesium chloride and
MnCl2 in a 3:1 ratio, proceeded effectively and 2-allyl-1-
phenyl-1,4-pentadiene 913) was obtained in 65% yield.
However, in the case of magnesium manganate, the use of
the unprotected alcohol as a substrate resulted in a consider-
able decrease of the yield of 13 9entries 4±6). 95) This
reaction was applicable for the preparation of an exo-
methylene compound 9entry 7). 96) The reaction of 18
with n-Bu3MnLi afforded the diene 19 in moderate yield
9entry 8).
P
3MnLih
n-Bu3MnLi 76 95)
P 3MnLi h 87 96)
78 94)
7
n-C6H13 SiMe3 93)
n-C6H13 SiMe3 93)
8c
The reactions were performed with dibromoalkane 91.0 mmol) and manga-
nate 91.2 mmol) in THF unless otherwise noted.
Yields are based on dibromoalkane and are isolated yield.
a
b
Manganate 92.2 mmol) was used.
The reaction was performed with 3 90.5 mmol) and Ph3MnLi 91.1 mmol)
in THF.
c
92) The use of 1.2 equiv. of trialkylmanganate is suf®cient.
The yield of 2 was not improved by the use of 2.2 equiv. of
the manganate 9entry 3). 93) The reaction of 1-benzyloxy-
2,2-dibromo-1-phenylethane 91c) afforded 2 in moderate
yield 9entry 4). 94) The use of unprotected alcohol 1d as a
substrate afforded 2 in moderate yield 9entry 5). 95)
Ph3MnLi provided the desired phenylated alkene 4 in
good yield 9entry 6). 96) The substrate 3 9R1ˆn-C6H13)
also provided the corresponding alkenes upon treatment
with trialkylmanganates 9entries 7 and 8).
To our surprise, the reaction of acetate 11e with
lithium tributylmanganate provided 1-phenyl-1-hexene 92,
We also investigated the reaction of 7 to examine the feasi-
bility of the synthesis of trisubstituted alkenes. Treatment of
7a with tributylmanganate afforded pentylidenecyclohexane
98) in 47% yield. The reaction of 7b with 2.2 equiv. of
n-Bu3MnLi furnished the desired trisubstituted alkene 8 in
46% yield 9Scheme 3).
Table 2. The reaction of tribromoalkanes with trialkylmanganate
A trisubstituted alkene can be also prepared from dibromo
compound 9. Treatment of 9 with 2.2 equiv. of tributyl-
manganate provided 10 9E/Zˆ68/32) in 57% yield
9Scheme 4).
Entry R1
R2
R3 MnMtl
Yield 9%)a
3
1
2
3
P
P
P
h
h
h
t-BuMSie2 911b) n-Bu3MnLi
2P hC91H1c)
11dH) 9
58b 912)
43 912)
44 912)
n-Bu3MnLi
n-Bu3MnLi
4
5
6
Ph
SiMe3 911a)
11dH) 9
65b 913)
24 913)
43 915)
We then turned our attention toward the reaction of tri-
bromoalkanes. Treatment of 1,1,1-tribromo-2-phenyl-2-
P
h
n-C6H13
SiMe3 914)
7
8
H
Sit-BuMe2 916)
n-Bu3MnLi
n-Bu3MnLi
49b 917)
48 919)
PhCHˆCH SiMe3 918)
The reactions were performed with tribromoalkane 91.0 mmol) and manga-
nate 92.2 mmol) in THF.
Yields are based on tribromoalkane and are isolated yields.
a
b
NMR yield.
Scheme 3.

H. Kakiya et al. / Tetrahedron 57 ,2001) 10063±10069
10065
Scheme 6.
The migration±elimination reaction also proved to be
effective to synthesize tetrasubstituted alkenes. Treatment
of 1-9tribromomethyl)cyclohexanol 922a) with lithium
tributylmanganate provided the dibutylated alkene 23 in
69% yield 9Scheme 7).
Scheme 7.
The results of the reaction of various tribromoalkanes with
manganates are shown in Table 3. Several characteristics of
this reaction are noteworthy.13 91) The reaction with
Ph3MnLi provided the product 24 9entry 2). 92) Magnesium
manganate 9R3MnMgX) was as effective as lithium tri-
alkylmanganate 9R3MnLi) 9entries 3 and 4). 93) The use of
trimethylsilyl ether 22b resulted in a decrease in the yield of
the product 9entry 5). 94) In the case of 28, a tetrasubstituted
alkene with three different substituents was obtained 9entry
7).
Table 3. Preparation of tetrasubstituted alkene
Entry R1
R2
R3
R4 MnMtl
Yield 9%)a
3
1
2
3
±9CH2)5±
±9CH2)5±
±9CH2)5±
H 922a)
H 922a)
H 922a)
n-Bu3MnLi
P 3MnLhi
n-Bu3MnMgBr
69 923)
53 924)
56 923)
4
5
6
7
±9CH2)5±
±9CH2)5±
n-Bu
H 922a)
59 925)
13 925)
56 927)
62 929)
We propose the following reaction mechanism for the
formation of alkenes 9Scheme 8): Initial bromine±manga-
nese exchange to afford 31, alkyl migration from manganese
to adjacent carbon under Br2 elimination producing 32.
When X is hydrogen, elimination of Mn and the alkoxy
group at the b-position takes place to give the alkene 33.
Meanwhile, when X is Br, dialkylated alkenes 36 is
produced by the following pathway: generation of manga-
nate 34 by the action of another trialkylmanganate, further
1,2-migration of the alkyl group of 34 providing 35, and
elimination of Mn and the alkoxy group.14
SiMe3 922b)
n-Bu H 926)
Me H 928)
n-C5H11
n-Bu3MnLi
The reactions were performed with tribromo compound 91.0 mmol) and
manganate 92.2 mmol) in THF at 08C for 1 h.
Yields are based on tribromo compound and are isolated yields.
a
E/Zˆ87/13) in 50% yield along with the desired trisubsti-
tuted alkene 12 in 13% yield. The use of n-Bu3MnMgBr
also afforded 2, predominately. Moreover, the sequential
treatment of 11e with tributylmanganate and benzaldehyde
afforded allylic alcohol 20 in 36% yield. On the basis of
these facts, it is obvious that vinyl manganese species 21 is
formed in situ 9Scheme 6).
3. Conclusion
We found that 1,1-di- or 1,1,1-tribromoalkanes bearing a
b-alkoxy group provided the alkylated alkenes upon
Scheme 8.

10066
H. Kakiya et al. / Tetrahedron 57 ,2001) 10063±10069
treatment with trialkylmanganates via a migration±elimina-
tion sequence. In the reaction of a gem-dibromoalkane with
tributylmanganate, which we have reported earlier,12 two
regioisomeric alkenes were obtained because of the
presence of two types of b-hydrogen atoms. However, the
reaction described in this report provided an alkene as a
single regioisomer because an alkoxy group was eliminated
selectively over b-hydrogen. In the reaction of dibromo
compounds, lithium trialkylmanganese was much more
effective than the corresponding magnesium ate complex
to achieve incorporation of the alkyl group on manganese
into the products. In contrast, trialkylmanganates, derived
from Grignard reagents, were also applicable in the reaction
of tribromoalkanes.
4.1.3. 5--Tribromomethyl)-5-nonanol -26). IR 9neat)
3558, 2932, 2872, 1466, 1379, 1342, 1285, 1126, 1037,
1
708 cm21; H NMR 9CDCl3) d 0.96 9t, Jˆ7.2 Hz, 6H),
1.30±1.60 9m, 8H), 1.95±2.16 9m, 4H), 2.40 9s, 1H); 13C
NMR 9CDCl3) d 13.86, 23.20, 27.38, 35.56, 66.34, 82.99.
Found: C, 30.21; H, 4.83%. Calcd for C10H19Br3O: C, 30.41;
H, 4.85%.
4.1.4. 1,1,1-Tribromo-2-methyl-2-heptanol -28). IR 9neat)
3548, 3466, 2952, 2926, 2864, 1461, 1377, 1345, 1136,
1
1089, 1046, 963, 894, 794, 721 cm21; H NMR 9CDCl3) d
0.93 9t, Jˆ6.9 Hz, 3H), 1.24±1.61 9m, 6H), 1.63 9s, 3H),
1.96±2.18 9m, 2H), 2.36 9bs, 1H); 13C NMR 9CDCl3) d
13.90, 21.44, 22.52, 24.59, 32.16, 35.90, 65.66, 82.86.
Found: C, 26.48; H, 4.01%. Calcd for C8H15Br3O: C,
26.19; H, 4.12%.
4. Experimental
4.2. Preparation of silyl ether
Melting points were obtained on a Yanako MP-50929 melt-
ing point apparatus and are uncorrected. NMR spectra 91H
and 13C) were recorded on a Varian GEMINI 300 spectro-
meter in CDCl3; tetramethylsilane 9TMS) was used as an
internal standard. IR spectra were determined on a
SHIMADZU FTIR-8200PC spectrometer. Mass spectra
were determined on a JEOL Mstation 700 spectrometer.
Silica gel 9Wakogel 200 mesh) was used for column chro-
matography. The analyses were carried out at the Elemental
Analysis Center of Kyoto University. Unless otherwise
noted, materials obtained from commercial suppliers were
used without further puri®cation. Tetrahydrofuran 9THF)
was freshly distilled from sodium benzophenone ketyl
before use. Anhydrous manganese9II) chloride purchased
from Aldrich was heated at 1608C for 2 h, prior to use.
Method A. Preparation of 1,1-dibromo-2-phenyl-2-9trimethyl-
siloxy)ethane 91b) is representative. Trimethylsilyl chloride
90.60 g, 5.5 mmol), imidazole 90.37 g, 5.5 mmol), and
4-dimethylaminopyridine 912 mg, 0.1 mmol) were added
to 2,2-dibromo-1-phenylethanol 91d, 1.40 g, 5.0 mmol) in
DMF 98 mL). The mixture was stirred for 2 h at room
temperature. The reaction was quenched with water and
the mixture was extracted with hexane. Puri®cation by silica
gel column chromatography afforded 1,1-dibromo-2-phenyl-
2-9trimethylsiloxy)ethane 91b, 1.57 g, 4.5 mmol) in 89%
yield. In a similar fashion, 1,1-dibromo-2-9trimethylsiloxy)-
octane 93), 1,1,1-tribromo-2-phenyl-2-9trimethylsiloxy)-
ethane 911a), 1,1,1-tribromo-2-9trimethylsiloxy)octane 914),
1,1,1-tribromo-2-9t-butyldimethylsiloxy)ethane 916), and
4,4,4-tribromo-1-phenyl-3-9trimethylsiloxy)-1-butene 918)
were prepared.
4.1. Starting materials
Method B. Preparation of 1,1,1-tribromo-2-9t-butyl-
dimethylsiloxy)-2-phenylethane 911b) is representative.
t-Butyldimethylsilyl tri¯uoromethanesulfonate 91.90 g,
7.2 mmol) was added to a mixture of 2,2,2-tribromo-1-
phenylethanol 911d, 2.15 g, 6.0 mmol) and 2,6-lutidine
91.29 g, 12.0 mmol) in dichloromethane 96 mL) at room
temperature. The mixture was stirred for 7 h. The reaction
was quenched with 1 M HCl. Extraction with hexane,
followed by silica gel column puri®cation afforded 1,1,1-
tribromo-2-9t-butyldimethylsiloxy)-2-phenylethane 911b,
2.62 g, 5.6 mmol) in 93% yield. In a similar fashion,
1-dibromomethyl-1-9trimethylsiloxy)cyclohexane 97a) and
According to literature procedures, 1,1-dibromo-2-9t-butyl-
dimethylsiloxy)-2-phenylethane 91a),15 1-9dibromomethyl)-
cyclohexanol 97b),16 and 1-9tribromomethyl)cyclohexanol
922a)16 were prepared. In a similar fashion,16 2,2-dibromo-
1-phenylethanol 91d), 2,2-dibromo-1-phenyl-1-propanol
99), 2,2,2-tribromo-1-phenylethanol 911d), 5-9tribromo-
methyl)-5-nonanol 926), and 1,1,1-tribromo-2-methyl-2-
heptanol 928) were prepared.
Spectroscopic data for 2,2-dibromo-1-phenylethanol 91d)
were identical with those reported in the literature.17
1-tribromomethyl-1-9trimethylsiloxy)cyclohexane
were prepared.
922b)
4.1.1. 2,2-Dibromo-1-phenyl-1-propanol -9). IR 9neat)
3454, 1454, 1377, 1043, 756, 702 cm21
;
1H NMR
9CDCl3) d 2.41 9s, 3H), 3.12 9s, 1H), 5.00 9s, 1H), 7.32±
7.40 9m, 3H), 7.49±7.58 9m, 2H); 13C NMR 9CDCl3) d
35.55, 74.78, 83.32, 127.90, 128.83, 129.00, 136.32.
Found: C, 36.83; H, 3.47%. Calcd for C9H10Br2O: C,
36.77; H, 3.43%.
4.2.1. 1,1-Dibromo-2-phenyl-2--trimethylsiloxy)ethane
-1b). IR 9neat) 2959, 1454, 1254, 1136, 1094, 964, 878,
1
843, 756, 702 cm21; H NMR 9CDCl3) d 0.11 9s, 9H),
4.96 9d, Jˆ5.1 Hz, 1H), 5.65 9d, Jˆ5.1 Hz, 1H), 7.31±
7.42 9m, 5H); 13C NMR 9CDCl3) d 20.07, 51.37, 79.82,
127.33, 128.23, 128.65, 139.91. Found: C, 37.34; H,
4.50%. Calcd for C11H16Br2OSi: C, 37.52; H, 4.58%.
4.1.2. 2,2,2-Tribromo-1-phenylethanol -11d). Mp 768C;
1
IR 9nujol) 3506, 1049, 750, 694 cm21; H NMR 9CDCl3)
d 3.50 9d, Jˆ3.6 Hz, 1H), 5.17 9d, Jˆ3.6 Hz, 1H), 7.34±
7.46 9m, 3H), 7.68±7.74 9m, 2H); 13C NMR 9CDCl3) d
54.50, 85.81, 127.73, 129.52, 129.71, 135.24. Found: C,
26.94; H, 2.01%. Calcd for C8H7Br3O: C, 26.78; H, 1.97%.
4.2.2. 1,1-Dibromo-2--trimethylsiloxy)octane -3). IR
;
9neat) 2957, 2928, 2858, 1252, 1103, 843, 750, 687 cm21
1H NMR 9CDCl3) d 0.20 9s, 9H), 0.89 9t, Jˆ6.3 Hz, 3H),
1.18±1.48 9m, 8H), 1.56±1.84 9m, 2H), 3.80±3.87 9m, 1H),

H. Kakiya et al. / Tetrahedron 57 ,2001) 10063±10069
10067
5.60 9d, Jˆ3.3 Hz, 1H); 13C NMR 9CDCl3) d 0.33, 13.95,
4.3. Preparation of benzyl ether18
22.47, 25.22, 29.03, 31.62, 33.68, 51.79, 77.27. Found: C,
36.69; H, 6.78%. Calcd for C11H24Br2OSi: C, 36.68; H,
6.72%.
Benzylation of 2,2,2-tribromo-1-phenylethanol 911d) is
representative. Benzyl 2,2,2-trichoroacetimidate 93.48 g,
13.8 mmol) and 2,2,2-tribromo-1-phenylethanol 911d,
2.60 g, 7.3 mmol) were dissolved in CH2Cl2 950 mL).
After cooling to 08C, trimethylsilyl tri¯uoromethane-
sulfonate 9222 mg, 1.0 mmol) was added slowly and the
mixture was stirred for 24 h at room temperature. The
solvent was removed in vacuo and diethyl ether was
added to the residue. The mixture was poured into 0.5 M
NaOH solution and extracted with Et2O. The combined
organic layers were washed with 1 M HCl and with sat.
NaHCO3 solution and concentrated in vacuo. Puri®cation
by silica gel column chromatography provided 2-benzyl-
oxy-1,1,1-tribromo-2-phenylethane 911c) in 40% yield. In
a similar fashion, 1-benzyloxy-2,2-dibromo-1-phenylethane
91c) was prepared.
4.2.3. 1-Dibromomethyl-1--trimethylsiloxy)cyclohexane
-7a). IR 9neat) 2932, 2854, 1252, 1174, 1139, 1094, 1072,
896, 840, 753, 687 cm21; 1H NMR 9CDCl3) d 0.23 9s, 9H),
1.16±1.35 9m, 1H), 1.46±1.62 9m, 5H), 1.68±1.86 9m, 4H),
5.69 9s, 1H); 13C NMR 9CDCl3) d 2.56, 22.28, 25.26, 34.81,
58.40, 78.47. Found: C, 34.73; H, 5.89%. Calcd for
C10H20Br2OSi: C, 34.90; H, 5.86%.
4.2.4.
1,1,1-Tribromo-2-phenyl-2--trimethylsiloxy)-
ethane -11a). Mp 438C; IR 9nujol) 1254, 1124, 880, 843,
762, 691, 573 cm21; 1H NMR 9CDCl3) d 0.11 9s, 9H), 5.08
9s, 1H), 7.30±7.43 9m, 3H), 7.64±7.70 9m, 2H); 13C NMR
9CDCl3) d 20.10, 53.73, 86.32, 127.45, 129.11, 130.02,
137.56. Found: C, 30.44; H, 3.41%. Calcd for
C11H15Br3OSi: C, 30.65; H, 3.51%.
4.3.1. 1-Benzyloxy-2,2-dibromo-1-phenylethane -1c). IR
9neat) 3026, 1493, 1454, 1071, 1027 cm21 1H NMR
;
9CDCl3) d 4.44 9d, Jˆ11.7 Hz, 1H), 4.64 9d, Jˆ11.7 Hz,
1H), 4.69 9d, Jˆ5.7 Hz, 1H), 5.71 9d, Jˆ5.7 Hz, 1H),
7.32±7.47 9m, 10H); 13C NMR 9CDCl3) d 47.61, 71.60,
84.86, 120.06, 128.15, 128.32, 128.52, 129.21, 136.81,
137.25. HRMS Found: m/z 262.8890. Calcd for
C8H779Br81Br: 9M2PhCH2O), 262.8894.
4.2.5. 1,1,1-Tribromo-2--t-butyldimethylsiloxy)-2-phenyl-
ethane -11b). IR 9neat) 2950, 2926, 2882, 2852, 1472,
1463, 1455, 1257, 1198, 1119, 1074, 864, 837, 778, 762,
703, 692 cm21; 1H NMR 9CDCl3) d 20.22 9s, 3H), 0.20 9s,
3H), 0.94 9S, 9H), 5.07 9s, 1H), 7.32±7.43 9m, 3H), 7.65±
7.72 9m, 2H); 13C NMR 9CDCl3) d 25.15, 24.76, 18.15,
25.52, 53.67, 86.46, 127.45, 129.18, 130.10, 137.71. Found:
C, 35.53; H, 4.49%. Calcd for C14H21Br3OSi: C, 35.54; H,
4.47%.
4.3.2. 2-Benzyloxy-1,1,1-tribromo-2-phenylethane -11c).
IR 9neat) 3058, 3026, 2864, 1492, 1454, 1092, 1070, 1029,
992, 752, 730, 705, 693 cm21; 1H NMR 9CDCl3) d 4.52 9d,
Jˆ12.0 Hz, 1H), 4.70 9d, Jˆ12.0 Hz, 1H), 4.83 9s, 1H),
7.28±7.49 9m, 8H), 7.65±7.73 9m, 2H); 13C NMR
9CDCl3) d 48.37, 72.04, 90.77, 127.80, 128.08, 128.23,
128.39, 129.49, 130.52, 134.49, 136.68. HRMS Found:
m/z 342.7969. Calcd for C8H679Br81Br2: 9M2PhCH2O),
342.7979.
4.2.6. 1,1,1-Tribromo-2--trimethylsiloxy)octane -14). IR
9neat) 2959, 2928, 2858, 1458, 1342, 1252, 1142, 1109, 901,
843, 750, 706 cm21; 1H NMR 9CDCl3) d 0.28 9s, 9H), 0.91
9t, Jˆ6.6 Hz, 3H), 1.23±1.59 9m, 8H), 1.60±1.73 9m, 1H),
2.14±2.25 9m, 1H), 3.92 9dd, Jˆ9.0, 1.8 Hz, 1H); 13C NMR
9CDCl3) d 0.83, 13.91, 22.45, 26.30, 28.99, 31.58, 34.24,
55.21, 85.95. HRMS Found: m/z 187.1526. Calcd for
C11H23Br3OSi: 9M2CBr3), 187.1518.
4.3.3. Preparation of 2,2,2-tribromo-1-phenylethyl
acetate -11e). Acetic anhydride 91.02 g, 10 mmol) and
4-dimethylaminopyridine 912 mg, 0.10 mmol) were added
to a mixture of 2,2,2-tribromo-1-phenylethanol 911d,
1.79 g, 5.0 mmol) and pyridine 91.58 g, 20 mmol) at room
temperature. The mixture was warmed up to 608C and stir-
red for 5 h at 608C. After the mixture had been cooled down
to room temperature, toluene 920 mL) was added to the
resulting mixture. Then, the mixture was dried over
Na2SO4 and the solvent was removed in vacuo. Puri®cation
by silica gel column chromatography afforded 11e in 81%
yield: mp 1448C; IR 9nujol) 1745, 1225, 1039, 928, 766,
4.2.7. 1,1,1-Tribromo-2--t-butyldimethylsiloxy)ethane
-16). IR 9neat) 2930, 2856, 1472, 1464, 1258, 1146, 841,
779, 702, 633 cm21; 1H NMR 9CDCl3) d 0.19 9s, 6H), 0.97
9s, 9H), 4.28 9s, 2H); 13C NMR 9CDCl3) d 25.23, 18.28,
25.62, 45.45, 79.33. Found: C, 24.49; H, 4.23%. Calcd for
C8H17Br3OSi: C, 24.40; H, 4.32%.
4.2.8.
4,4,4-Tribromo-1-phenyl-3--trimethylsiloxy)-1-
butene -18). Mp 698C; IR 9nujol) 1449, 1255, 1122, 1104,
965, 887, 842, 752, 693 cm21; 1H NMR 9CDCl3) d 0.25 9s,
9H), 4.63 9d, Jˆ6.6 Hz, 1H), 6.38 9dd, Jˆ15.9, 6.6 Hz, 1H),
6.82 9d, Jˆ15.9 Hz, 1H), 7.26±7.39 9m, 3H), 7.42±7.47 9m,
2H); 13C NMR 9CDCl3) d 0.35, 53.15, 85.54, 126.10,
126.95, 128.49, 128.83, 136.00, 136.15. Found: C, 33.98;
H, 3.66%. Calcd for C13H17Br3OSi: C, 34.16; H, 3.75%.
1
712, 692 cm21; H NMR 9CDCl3) d 2.23 9m, 3H), 6.40 9s,
1H), 7.35±7.48 9m, 3H), 7.69±7.76 9m, 2H); 13C NMR
9CDCl3) d 20.78, 45.16, 83.67, 127.87, 129.79, 130.13,
133.87, 168.71. Found: C, 29.88; H, 2.19%. Calcd for
C10H9Br3O2: C, 29.96; H, 2.26%.
4.2.9. 1-Tribromomethyl-1--trimethylsiloxy)cyclohexane
-22b). IR 9neat) 2940, 2856, 1250, 1168, 1094, 902, 840,
4.4. General procedure for the preparation of alkene
1
753, 697 cm21; H NMR 9CDCl3) d 0.30 9m, 9H), 1.07±
The reaction of 1-9tribromomethyl)cyclohexanol 922a) with
tributylmanganate is representative. Manganese9II) chloride
9277 mg, 2.2 mmol) was sonicated in THF 910 mL) under
argon atmosphere for 10 min. Butyllithium 91.6 M hexane
solution, 4.1 mL, 6.6 mmol) was added to the suspension of
1.24 9m, 1H), 1.41±1.80 9m, 5H), 1.95±2.09 9m, 2H), 2.11±
2.22 9m, 2H); 13C NMR 9CDCl3) d 2.81, 22.64, 25.00,
32.31, 65.86, 86.32. HRMS Found: m/z 171.1211. Calcd
for C9H19OSi: 9M2CBr3), 171.1205.

10068
H. Kakiya et al. / Tetrahedron 57 ,2001) 10063±10069
MnCl2 in THF at 08C. The mixture turned into a clear brown
solution and the solution was stirred for 20 min at 08C. A
solution of 1-9tribromomethyl)cyclohexanol 922a, 351 mg,
1.0 mmol) in THF 92 mL) was added at 08C. The mixture
was stirred at 08C for 1 h. The resulting mixture was poured
into water and extracted with hexane 920 mL£3). The
combined organic layers were dried over Na2SO4 and
concentrated in vacuo. The crude product was puri®ed by
silica gel column chromatography to provide 91-butyl-
pentylidene)cyclohexane 923, 144 mg) in 69% yield: IR
3368, 2950, 2924, 2856, 1493, 1450, 1021, 918, 749, 731,
1
698 cm21; H NMR 9CDCl3) d 0.87 9t, Jˆ7.2 Hz, 3H),
1.22±1.62 9m, 4H), 1.80 9bs, 1H), 1.88±2.02 9m, 1H),
2.10±2.23 9m, 1H), 5.88 9s, 1H), 6.61 9s, 1H) 7.20±7.39
9m, 10H); 13C NMR 9CDCl3) d 13.85, 22.60, 30.22, 31.03,
71.53, 125.89, 126.81, 127.09, 128.25, 128.29, 128.43,
128.74, 137.63, 142.50, 143.50. Found: C, 85.38; H,
8.39%. Calcd for C19H22O: C, 85.67; H, 8.32%.
4.4.6. -Diphenylmethylidene)cyclohexane -24). Mp 828C;
IR 9nujol) 1489, 1441, 1072, 995, 760, 704 cm21; 1H NMR
9CDCl3) d 1.53±1.66 9m, 6H), 2.19±2.29 9m, 4H), 7.10±
7.15 9m, 4H), 7.16±7.21 9m, 2H), 7.22±7.30 9m, 4H); 13C
NMR 9CDCl3) d 26.71, 28.58, 32.32, 126.09, 127.95,
129.88, 134.62, 139.27, 143.24. HRMS found: m/z
248.1562. Calcd for C19H20: M, 248.1565.
1
9neat) 2926, 2856, 1448, 1377, 1259, 1236, 851 cm21; H
NMR 9CDCl3) d 0.90 9t, Jˆ6.6 Hz, 6H), 1.22±1.35 9m, 8H),
1.43±1.64 9m, 6H), 1.98 9t, Jˆ7.2 Hz, 4H), 2.11 9m, 4H);
13C NMR 9CDCl3) d 14.00, 22.87, 27.00, 28.46, 30.39,
31.76, 31.91, 130.05, 133.01. HRMS Found: m/z
208.2192. Calcd for C15H28: M, 208.2191.
Spectroscopic data for 1-phenyl-1-hexene 92),19,20 5-dode-
cene 95),21 1-phenyl-1-octene 96),22,23 2-methyl-1-phenyl-1-
hexene 910),24 2-butyl-1-phenyl-1-hexene 912),25 2-allyl-1-
phenyl-1,4-pentadiene 913),25,26 and 4-9cyclohexylidene)-
1,6-heptadiene 925)25 were identical with those reported in
literatures.
4.4.7. 4-Allyl-5-butyl-1,4-nonadiene -27). IR 9neat) 2959,
1
2930, 2860, 1636, 1466, 1429, 1379, 993, 910 cm21; H
NMR 9CDCl3) d 0.90 9t, Jˆ6.9 Hz, 6H), 1.22±1.40 9m,
8H), 2.00 9t, Jˆ7.5 Hz, 4H), 2.75 9d, Jˆ6.0 Hz, 4H),
4.93±5.03 9m, 4H), 5.74 9ddt, Jˆ10.2, 16.8, 6.3 Hz, 2H);
13C NMR 9CDCl3) d 13.97, 22.97, 31.32, 31.60, 35.76,
114.69, 127.44, 137.19, 137.25. HRMS found: m/z
220.2182. Calcd for C16H28: M, 220.2191.
4.4.1. Pentylidenecyclohexane -8). IR 9neat) 2928, 2855,
1670, 1447, 833 cm21 1H NMR 9CDCl3) d 0.89 9t,
;
4.4.8. 5-Butyl-6-methyl-5-undecene -29). IR 9neat) 2952,
Jˆ6.9 Hz, 3H), 1.23±1.35 9m, 4H), 1.44±1.58 9m, 6H),
1.97 9dt, Jˆ6.9, 6.9 Hz, 2H), 2.02±2.15 9m, 4H), 5.07 9t,
Jˆ6.9 Hz, 1H); 13C NMR 9CDCl3) d 13.90, 22.19, 26.65,
26.90, 27.77, 28.57, 28.64, 32.33, 37.12, 121.53, 139.53.
Found: C, 86.72; H, 13.32%. Calcd for C11H20: C, 86.76;
H, 13.24%.
1
2920, 2854, 1466, 1458, 1377 cm21; H NMR 9CDCl3) d
0.82±0.96 9m, 9H), 1.17±1.42 9m, 14H), 1.61 9s, 3H), 1.92±
2.03 9m, 6H); 13C NMR 9CDCl3) d 13.99, 17.78, 22.58,
22.90, 23.00, 28.30, 30.99, 31.49, 31.71, 31.95, 32.00,
34.11, 128.58, 133.38. HRMS found: m/z 224.2500. Calcd
for C16H32: M, 224.2504.
4.4.2. 4-Allyl-1,4-undecadiene -15). IR 9neat) 2959, 2926,
2856, 1638, 1458, 1431, 1379, 993, 912 cm21; H NMR
1
Acknowledgements
9CDCl3) d 0.88 9t, Jˆ6.9 Hz, 3H), 1.19±1.42 9m, 8H),
2.00 9dt, Jˆ6.9, 6.9 Hz, 2H), 2.72 9d, Jˆ6.9 Hz, 2H), 2.77
9d, Jˆ6.9 Hz, 2H), 4.94±5.07 9m, 4H), 5.25 9t, Jˆ7.2 Hz,
1H), 5.66±5.85 9m, 2H); 13C NMR 9CDCl3) d 13.98, 22.54,
27.77, 28.96, 29.77, 31.69, 34.50, 41.25, 115.20, 115.75,
127.47, 135.00, 136.31, 137.24. HRMS Found: m/z
192.1880. Calcd for C14H24: M, 192.1878.
Financial support by Grant-in-Aids for Scienti®c Research
on 9Nos. 10208208 and 12305058) from the Ministry of
Education, Culture, Sports, Science, and Technology,
Japan, is acknowledged. H. K. thanks the JSPS Research
Fellowship for Young Scientists.
4.4.3. 2-Butyl-1-hexene -17). IR 9neat) 2930, 2860, 1645,
References
1466, 1379, 887 cm21 1H NMR 9CDCl3) d 0.91 9t,
;
Jˆ7.2 Hz, 6H), 1.24±1.48 9m, 8H), 2.00 9t, Jˆ6.9 Hz,
4H), 4.69 9s, 2H); 13C NMR 9CDCl3) d 13.90, 22.41,
29.95, 35.70, 108.35, 150.54. Found: C, 85.39; H,
14.60%. Calcd for C10H20: C, 85.63; H, 14.37%.
1. 9a) Preparation of Alkenes, Williams, J. M. J., Ed.; Oxford
University: New York, 1996. 9b) Julia, M. Pure Appl. Chem.
1985, 57, 763±768. 9c) Kelly, S. E. In Comprehensive Organic
Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon: New
York, 1991; Vol. 1, pp 729±817.
4.4.4. -1E)-4-Butyl-1-phenyl-1,3-octadiene -19). IR 9neat)
3024, 2952, 2924, 2856, 1638, 1596, 1496, 1466, 1459,
2. 9a) Maercker, A. Org. React. 1965, 14, 270±490. 9b) Maryan-
off, B. E.; Reitz, A. B. Chem. Rev. 1989, 89, 863±927.
9c) Wadsworth Jr., W. S. Org. React. 1977, 25, 73±253.
9d) Boutagy, J.; Thomas, R. Chem. Rev. 1974, 74, 87±99.
3. 9a) Chan, T.-H. Acc. Chem. Res. 1977, 10, 442±448. 9b) Ager,
D. J. Synthesis 1984, 384±398. 9c) Ager, D. J. Org. React.
1990, 38, 1±223.
1450, 1377, 959, 745, 689 cm21 1H NMR 9CDCl3) d
;
0.88±0.98 9m, 6H), 1.25±1.50 9m, 8H), 2.11 9t, Jˆ7.5 Hz,
2H), 2.26 9t, Jˆ7.5 Hz, 2H), 6.00 9d, Jˆ11.1 Hz, 1H), 6.44
9d, Jˆ15.6 Hz, 1H), 7.02 9dd, Jˆ11.1, 15.6 Hz, 1H), 7.14±
7.22 9m, 1H), 7.26±7.32 9m, 2H), 7.35±7.42 9m, 2H); 13C
NMR 9CDCl3) d 13.92, 22.48, 22.74, 30.36, 30.61, 31.06,
37.12, 125.00, 125.67, 126.14, 126.92, 128.61, 129.88,
138.31, 145.43. HRMS found: m/z 242.2027. Calcd for
C18H26: M, 242.2035.
4. 9a) Julia, M.; Paris, J.-M. Tetrahedron Lett. 1973, 14, 4833±
4836. 9b) Kocienski, P. In Comprehensive Organic Synthesis;
Trost, B. M., Fleming, I., Eds.; Pergamon: New York, 1991;
Vol. 6, pp 987±1000.
5. 9a) McMurry, J. E.; Lectka, T.; Rico, J. G. J. Org. Chem. 1989,
54, 3748±3749. 9b) Robertson, G. M. In Comprehensive
4.4.5. 2-Butyl-1,3-diphenyl-2-propen-1-ol -20). IR 9neat)

H. Kakiya et al. / Tetrahedron 57 ,2001) 10063±10069
10069
Scheme 9.
Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon:
5-9tribromomethyl)-5-nonanol with tributylmanganate, no
trace of the starting material was recovered. 5-Nonanone
and 5-butyl-5-nonanol were formed as byproducts. These
products would be formed as follows: The reaction of a hy-
droxy group with manganate afforded the manganese alkoxide
and the subsequent elimination of a tribromomethyl group
provided the ketone. The reaction of the resulting ketone
with tributylmanganate yielded 5-butyl-5-nonanol. In the
reaction of silyl ethers, silyl enol ethers were obtained as
byproducts through dehydrobromination.
New York, 1991; Vol. 3, pp 583±595.
6. Metal-catalyzed Cross-coupling Reactions, Diederich, F.,
Stang, P. J., Eds.; Wiley-VCH: Weinheim, 1998.
7. 9a) Knochel, P. In Comprehensive Organic Synthesis; Trost,
B. M., Fleming, I., Eds.; Pergamon: New York, 1991; Vol. 4,
pp 865±911. 9b) Labinger, J. A. In Comprehensive Organic
Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon: New
York, 1991; Vol. 8, pp 667±702.
8. Although M. W. Miller has recently reported that the
palladium-catalyzed reaction of 2-alkyl-1,1-dibromo-1-alkene
with an aryl boronic acid to provide a diarylated alkene, this
reaction provides none of dialkylated alkenes. See: Bauer, A.;
Miller, M. W.; Vice, S. F.; McCombie, S. W. Synlett 2001,
254±256.
14. The formation of 21 might be explained as follows. Bromine±
manganese exchange and 1,2-migration of butyl group
provides manganese species 38. Sequential elimination of
Mn and acetoxy group affords intermediary bromoalkene 39.
Then, bromoalkene 39 is converted into alkenylmanganese
species 21 through halogen±metal exchange under the reac-
tion condition 9Scheme 9). The chelation of the carbonyl
oxygen atom of the acetoxy group to manganese would
facilitate the elimination of the acetoxy group to provide 39.
15. Shinokubo, H.; Miura, K.; Oshima, K.; Utimoto, K.
Tetrahedron 1996, 52, 503±514.
9. T. Harada and A. Oku have reported the reaction of 2-alkyl-
1,1-dibromo-1-alkene with trialkylzincate to afford the mono
alkylated alkenyl zinc species, followed by palladium-
catalyzed coupling reaction to yield the tetrasubstituted
alkenes. However, the use of alkyl halides for electrophiles
was not reported. See: Harada, T.; Katsuhira, T.; Hara, D.;
Kotani, Y.; Maejima, K.; Kaji, R.; Oku, A. J. Org. Chem.
1993, 58, 4897±4907.
16. Taguchi, H.; Yamamoto, H.; Nozaki, H. Bull. Chem. Soc. Jpn.
1977, 50, 1588±1591.
17. Naskar, D.; Roy, S. Tetrahedron 2000, 56, 1369±1377.
18. Eckenberg, P.; Groth, U.; Huhn, T.; Richter, N.; Schmeck, C.
Tetrahedron 1993, 49, 1619±1624.
10. 9a) Normant, J. F.; Cahiez, G. Organomanganous Reagents in
Modern Synthetic Methods; Scheffold, R., Ed.; Otto Salle
Verlag GmbH: Frankfurt am Main, 1983; Vol. 3, pp 173±
216. 9b) Cahiez, G. In Encyclopedia of Reagents for Organic
Synthesis; Paquette, L., Ed.; J. Synth. Org. Chem., Jpn.;
Wiley: Chichester, 1995; 57, pp 925±928. 9c) Cahiez, G. In
Encyclopedia of Reagents for Organic Synthesis; Paquette, L.,
Ed.; Tetrahedron Lett.; Wiley: Chichester, 1995; 38, pp 3227±
3229.
19. Namboothiri, I. N. N.; Hassner, A. J. Organomet. Chem. 1996,
518, 69±77.
20. Tucci, F. C.; Chief®, A.; Comasseto, J. V. J. Org. Chem. 1996,
61, 4975±4989.
21. Caheiz, G.; Avedissan, H. Synthesis 1998, 1199±1205.
È
È
22. Schade, P.; Schafer, T.; Mullen, K.; Bender, D.; Knoll, K.;
Bronstert, K. Chem. Ber. 1991, 124, 2833±2841.
23. Kauffman, T.; Rauch, E.; Schulz, J. Chem. Ber. 1973, 106,
1612±1617.
11. 9a) Oshima, K. J. Organomet. Chem. 1999, 575, 1±20.
9b) Shinokubo, H.; Oshima, K. J. Synth. Org. Chem., Jpn.
1999, 57, 13±23.
24. Crandall, J. K.; Collonges, F. J. Org. Chem. 1976, 41, 4089±
4092.
Â
25. Barluenga, J.; Yus, M.; Concellon, J. M.; Bernad, P. J. Org.
Chem. 1981, 46, 2721±2726.
12. 9a) Kakiya, H.; Inoue, R.; Shinokubo, H.; Oshima, K.
Tetrahedron Lett. 1997, 38, 3275±3278. 9b) Kakiya, H.;
Shinokubo, H.; Oshima, K. Bull. Chem. Soc. Jpn. 2000, 73,
2139±2147.
Â
26. Calo, V.; Lopez, L.; Nacci, A.; Mele, G. Tetrahedron 1995,
Â
13. In spite of extensive attempts to optimize the reaction
conditions, the yield remained moderate. In the reaction of
51, 8935±8940.