Synthesis of prenylarenes and related (multisubstituted allyl)arenes from aryl halides and homoallyl alcohols via palladium-catalyzed retro-allylation

Article abstract of DOI:10.1246/bcsj.82.249

The reactions of aryl halides with 2,3,3-trimethyl-4-penten-2-ol in the presence of a palladium catalyst result in prenyl transfer from the alcohol to aryl halides via retro-allylation, yielding prenylarenes. Other multisubstituted allyl groups such as th

Full text of DOI:10.1246/bcsj.82.249

© 2009 The Chemical Society of Japan
Bull. Chem. Soc. Jpn. Vol. 82, No. 2, 249–253 (2009)
249
Synthesis of Prenylarenes and Related (Multisubstituted Allyl)arenes
from Aryl Halides and Homoallyl Alcohols via
Palladium-Catalyzed Retro-Allylation
Masayuki Iwasaki, Hideki Yorimitsu,* and Koichiro Oshima*
Department of Material Chemistry, Graduate School of Engineering, Kyoto University,
Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510
Received August 27, 2008; E-mail: yori@orgrxn.mbox.media.kyoto-u.ac.jp, oshima@orgrxn.mbox.media.kyoto-u.ac.jp
The reactions of aryl halides with 2,3,3-trimethyl-4-penten-2-ol in the presence of a palladium catalyst result in
prenyl transfer from the alcohol to aryl halides via retro-allylation, yielding prenylarenes. Other multisubstituted allyl
groups such as the 2,3-dimethyl-2-butenyl group are introduced to aromatic rings.
HO
O
Prenyl-substituted arenes are often found in natural products,
most of which show significant biological activities (Figure 1).
The synthesis of such biologically interesting compounds has
hence been well investigated.1 However, construction of
prenylarene skeletons is usually difficult. For instance, accord-
ing to a report by Knölker et al. about the synthesis of
carquinostatin A,2 the use of a large excess of nickel complex 1
was essential to afford 3 with satisfactory efficiency and
selectivity (Scheme 1). Moreover, a large amount of highly
toxic Ni(CO)4 was required for the preparation of 1, which can
be a significant drawback. In most cases, the conventional
cross-coupling reactions of aryl halides with prenylmetal
reagents provide a mixture of regioisomers (eq 1).3,4 Excep-
tionally, prenyltrifluorosilane reacted with aryl triflates under
palladium catalysis to afford prenylarenes predominantly
(eq 2).4 However, the reactions were performed in sealed tubes
and required a moisture-sensitive prenylmetal. Thus, little is
known concerning regioselective and convenient prenylation
reactions of aryl halides.
OMe
HN
OMe
HO
OH
CHO
Micromeline
Licoricidin
HN
O
O
HO
O
OH
Carquinostatin A
O
Dimethylsuberosin
Figure 1. Some natural products bearing prenyl groups.
Br
3 equiv Ni(CO)4
Ni Ni
Br
Pd cat.
Ar
Mtl
Ar
benzene
60 °C, 1 h
Br
1
X
+
Ar
ð1Þ
ð2Þ
Br
cat. PdCl2(dppp)
prenyltrifluorosilane
TBAF
CO2Me
60%
CO2Me
3 equiv 1
HN
HN
OMe
OMe
DMF
65 °C, 15 h
81%
THF, 120 °C
OMe
OMe
OTf
2
OAc
3
OAc
Very recently, we have developed the palladium-catalyzed
allylation reaction of aryl halides with homoallyl alcohols via
palladium-catalyzed retro-allylation.5 The reaction proceeds
with high regiospecificity, providing a variety of allylated
arenes. The prenylation of 1-bromonaphthalene with homo-
allyl alcohol 4 was previously investigated (Scheme 2).5a,5b
Notably, the prenylation reaction was perfectly regioselective,
and none of the regioisomer was obtained.5b However, this is
the only example of the prenylation reaction in the previous
Scheme 1. A rare example of selective prenylation of aryl
halide.
papers. In light of the importance of installing a prenyl moiety
to aromatic compounds, we further examined the generality of
the prenylation reaction of aryl halides with 4. We report here
the details of the prenylation reaction and related reactions that
introduce multisubstituted allyl groups into aryl halides.
Published on the web February 13, 2009; doi:10.1246/bcsj.82.249

250
Bull. Chem. Soc. Jpn. Vol. 82, No. 2 (2009)
Introduction of Multisubstituted Allyl Groups
0.050 equiv Pd(OAc)2
Table 1. Palladium-Catalyzed Prenylation of Aryl Halides
with Homoallyl Alcohol 4a)
0.10 equiv P(cC6H11 3
)
Np
OH
1.4 equiv Cs2CO3
Ar
X
cat. Pd(OAc)2/P(cC6H11 3
)
Ar
toluene, reflux, 12 h
79%
Cs2CO3
Cl
(4, 1.2 equiv)
OH
(Np = 1-naphthyl)
toluene, reflux, time
oxidative
addition
reductive
elimination
5
4
Np
Pd
Pd
Np
Cl
O
Np
Entry
1
ArÍX
Time/h
5
Yield/%
Pd
ligand
exchange
retro-allylation
17
5a
100
Cl
Scheme 2.
2
10
5b
98
Cl
Results and Discussion
Ph
10
Cl
A variety of aryl halides were subjected to the palladium-
3
4
5c
86
80
catalyzed prenylation reaction with 4 (Table 1). Since highly
electron-donating tricyclohexylphosphine was used as the
ligand, aryl chlorides6 were able to undergo the prenylation.
The reactions of ortho-substituted chloroarenes proceeded with
excellent efficiency (Entries 1Í3). On the other hand, the
prenylation reactions of 2-chloronaphthalene and 4-chloro-
toluene were slow, and required 26 h to complete (Entries 5
and 6). Although the reactions of 4-chlorostyrene and 4-
chloroanisole were also inefficient at reflux in toluene, a higher
temperature under microwave irradiation7 could accelerate
the reaction (Entries 7 and 8). In the reactions of sterically
demanding aryl chlorides (Entries 1Í3), the retro-allylation
step would be accelerated by the steric repulsion around the
palladium center. The high temperature could enhance the rate-
determining retro-allylation step in the reactions in Entries 7
and 8, where smaller steric repulsion would operate.5c Notably,
none of the oligomers of 4-chlorostyrene, which could be
formed through MizorokiÍHeck reaction,8 were observed. The
reaction conditions were mild enough to leave ester as well as
acetyl groups untouched (Entries 9Í11). Under the standard
conditions, 3-bromopyridine resisted the reaction, and a high
temperature was essential to attain a satisfactory result
(Entry 12). Both 3-chloropyridine and 2-bromopyridine suf-
fered from very low conversions under several sets of reaction
conditions we tested. Unprotected hydroxy and amino groups
completely suppressed the reaction. A dimethylamino substitu-
ent also retarded the reaction (Entry 13). Attempts to use 1-
alkenyl halides resulted in very low yields.
Ph
15
5d
Cl
5
26
5e
93
Cl
6
7
26
5f
84b)
Cl
11
5g
38 (84)c)
Cl
MeO
O
8
9
15
5h
27 (95)c)
Cl
EtO
15
5i
100
Cl
O
10
11
15
5j
80
67
Cl
O
10
5k
Cl
Not only the prenyl group but also a trisubstituted allyl
group could be incorporated. The reactions of aryl halides with
alcohol 6 provided 2,3-dimethyl-2-butenylarenes 7 through the
transposition of the double bond (Scheme 3). The reactions are
high-yielding under microwave irradiation at 250 °C, although
the reaction of 1-chloronaphthalene with 6 in boiling toluene
for 13 h resulted in low conversion, providing 7a in only 31%
yield. Preparation of such tetrasubstituted alkenes by conven-
tional Wittig-type olefination often results in low yields.
Stereoselective synthesis of trisubstituted alkenes was
performed by using 8, which have two different substituents,
methyl and the other bulkier groups at the allylic position
(eq 3). Formation of the E isomers of 9 predominated, and the
stereoselectivity can be rationalized as outlined in Scheme 4.
Upon the retro-allylation reaction of 8, a chair-like transition
12
13
10
5l
<5 (62)c)
N
Br
Me2N
17
5m
20
Br
a) Conditions: ArÍX (0.50 mmol), alcohol 4 (0.60 mmol),
Pd(OAc)2 (0.025 mmol), P(cC6H11)3 (0.050 mmol), Cs2CO3
(0.70 mmol), and toluene (2 mL). b) With Pd(OAc)2
(0.050 mmol) and P(cC6H11)3 (0.10 mmol). c) Performed under
microwave irradiation at 250 °C for 15 min.
state 10a would be the most favorable because the bulky R
group is located at the equatorial position. The other chair-like
transition state 10b has the R group at the axial position, which

M. Iwasaki et al.
Bull. Chem. Soc. Jpn. Vol. 82, No. 2 (2009)
251
0.050 equiv Pd(OAc)2
0.10 equiv P(cC6H11 3
1.4 equiv Cs2CO3
Ar
X
R
)
Ar
Pd–Np
OH
O
R
O
Pd–Np
toluene / DMF
MW, 250 °C, 15 min
7
10a
10b
6 (1.2 equiv)
7a 98% from
7b 89% from
7c 89% from
R
R
Pd–Np
O
Pd–Np
EtO
11a
11b
Cl
Cl
Br
Scheme 3. Synthesis of 2,3-dimethyl-2-butenylarenes.
(E)-9
(Z)-9
would render 10b disfavored. Formation of [(E)-alkenyl](naph-
thyl)palladium 11a is thus preferred. The intermediate 11a
finally undergoes smooth reductive elimination to yield (E)-9
selectively.
Scheme 4. Origin of stereoselectivity.
were obtained from TCI and Acros, respectively. The homoallyl
alcohol 4 was prepared according to the literature.5b
Typical Procedure. The reaction of Entry 1 in Table 1 is
representative. Cesium carbonate (0.23 g, 0.72 mmol) was placed
in a 30-mL two-necked reaction flask equipped with a Dimroth
condenser. The cesium carbonate was dried in vacuo by heating
with a hair dryer for 2 min. Palladium acetate (5.6 mg, 0.025 mmol)
was added to the reaction flask. The flask was then filled with
argon by using standard Schlenk technique. Tricyclohexylphos-
phine (0.50 M in toluene, 0.10 mL, 0.050 mmol) and toluene
(0.50 mL) were added and the resulting mixture was stirred for
10 min at room temperature. Toluene (1.5 mL), homoallyl alcohol
4 (73 mg, 0.60 mmol), and o-chlorotoluene (2a, 58 µL, 0.50 mmol)
were sequentially added at ambient temperature. The resulting
mixture was heated at reflux for 17 h. After the mixture was cooled
to room temperature, water (20 mL) was added. The product was
extracted with hexane (20 mL © 3). The combined organic layer
was dried over sodium sulfate, and concentrated in vacuo. Silica
gel column purification with hexane as an eluent gave 2-(3-methyl-
2-butenyl)toluene (5a, 0.080 g, 0.50 mmol) in 100% yield.
Characterization Data. Spectral data for 4,5b 5e,9 5h,10 5i,11
5j,12 and 7b13 are found in the literature.
Np–Cl
0.050 equiv Pd(OAc)2
0.10 equiv P(cC6H11 3
)
Np
OH
1.4 equiv Cs2CO3
toluene / DMF
MW, 250 °C, 15 min
Np = 1-naphthyl
ð3Þ
R
R
8a: R = iPr
8b: R = Ph
(1.2 equiv)
i
9a: R = Pr, 82%
E/Z = 92:8
9b: R = Ph, 72%
E/Z = 93:7
In conclusion, we have disclosed the palladium-catalyzed
prenylation and other related allylation of aryl halides that
yield (multisubstituted allyl)arenes by using retro-allylation of
homoallyl alcohols. The products are not readily available by
conventional methods. The present reactions will find applica-
tions for the synthesis of biologically intriguing compounds.
Experimental
General. 1H NMR (300 and 500 MHz) and 13C NMR (75.3
and 125.7 MHz) spectra were taken on Varian Mercury 300 and
UNITY INOVA 500 spectrometers and were recorded in CDCl3.
Chemical shifts (¤) are in parts per million relative to tetra-
methylsilane at 0.00 ppm for 1H and relative to CDCl3 at 77.0 ppm
for 13C unless otherwise noted. IR spectra were determined on
a SHIMADZU FTIR-8200PC spectrometer. Mass spectra were
determined on a JEOL Mstation 700 spectrometer. TLC analyses
were performed on commercial glass plates bearing a 0.25-mm
layer of Merck Silica gel 60F254. Silica gel (Wakogel 200 mesh)
was used for column chromatography. Elemental analyses were
carried out at the Elemental Analysis Center of Kyoto University.
The reactions under microwave irradiation were carried out
using a focused microwave unit (Biotage InitiatorTM). The
maximum irradiation power is 400 W. Each reaction was run in a
5-mL glass pressure vial, which is a commercially available vial
specifically for the Biotage InitiatorTM. It took 6 min to reach
250 °C. After reaching the indicated temperatures, controlled
microwave irradiation started and continued for 15 min, keeping
the reaction temperature constant.
2-(3-Methyl-2-butenyl)toluene (5a): IR (neat) 2971, 1490,
1
1451, 1377 cmÕ1; H NMR (CDCl3): ¤ 1.72 (s, 3H), 1.74 (s, 3H),
2.29 (s, 3H), 3.30 (d, J = 7.0 Hz, 2H), 5.22Í5.26 (m, 1H), 7.08Í
7.14 (m, 4H); 13C NMR (CDCl3): ¤ 17.84, 19.46, 25.73, 32.16,
122.49, 125.87, 125.93, 128.56, 130.01, 132.36, 136.12, 139.92.
Found: C, 89.75; H, 9.94%. Calcd for C12H16: C, 89.94; H,
10.06%.
1,3-Dimethyl-2-(3-methyl-2-butenyl)benzene (5b): IR (neat)
1
2977, 1472, 1376, 1099 cmÕ1; H NMR (CDCl3): ¤ 1.69 (s, 3H),
1.78 (s, 3H), 2.30 (s, 6H), 3.33 (d, J = 6.5 Hz, 2H), 4.97Í5.01 (m,
1H), 7.01 (s, 3H); 13C NMR (CDCl3): ¤ 17.93, 20.01, 25.63, 28.78,
121.94, 125.65, 128.00, 131.63, 136.25, 138.51. Found: C, 89.43;
H, 10.42%. Calcd for C13H18: C, 89.59; H, 10.41%.
2-(3-Methyl-2-butenyl)biphenyl (5c): IR (neat) 2973, 1479,
1010 cmÕ1; 1H NMR (CDCl3): ¤ 1.51 (s, 3H), 1.68 (s, 3H), 3.28 (d,
J = 7.0 Hz, 2H), 5.17Í5.21 (m, 1H), 7.21Í7.62 (m, 9H); 13C NMR
(CDCl3): ¤ 17.69, 25.69, 31.98, 123.64, 125.67, 126.70, 127.42,
127.98, 129.25, 129.33, 129.94, 131.94, 139.23, 141.74, 141.81.
Found: C, 91.94; H, 8.26%. Calcd for C17H18: C, 91.84; H, 8.16%.
4-(3-Methyl-2-butenyl)biphenyl (5d): Amorphous solid. IR
(nujol) 2982, 1734, 1558, 1489 cmÕ1; 1H NMR (CDCl3): ¤ 1.76 (s,
3H), 1.78 (s, 3H), 3.40 (d, J = 7.5 Hz, 2H), 5.36Í5.40 (m, 1H),
7.25Í7.28 (m, 2H), 7.32Í7.35 (m, 1H), 7.41Í7.45 (m, 2H), 7.51Í
7.54 (m, 2H), 7.57Í7.60 (m, 2H); 13C NMR (CDCl3): ¤ 17.85,
Unless otherwise noted, materials obtained from commercial
suppliers were used without further purification. Toluene and DMF
were purchased from Wako Pure Chemical Co. Toluene was
stored over slices of sodium. DMF was used as received. Tri(p-
tolyl)phosphine and cesium carbonate were purchased from Wako
Pure Chemical Co. Palladium acetate and tricyclohexylphosphine

252
Bull. Chem. Soc. Jpn. Vol. 82, No. 2 (2009)
Introduction of Multisubstituted Allyl Groups
25.78, 33.99, 123.01, 126.96, 127.01, 127.12, 128.68, 128.70,
132.71, 138.71, 140.94, 141.15. HRMS (EI) Found: 222.1404
[M+]; Calcd for C17H18: 222.1409.
4-(3-Methyl-2-butenyl)toluene (5f): IR (neat) 2975, 1516,
1104 cmÕ1; 1H NMR (CDCl3): ¤ 1.76 (s, 3H), 1.78 (s, 3H), 2.36 (s,
3H), 3.35 (d, J = 7.0 Hz, 2H), 5.34Í5.38 (m, 1H), 7.12 (s, 4H);
13C NMR (CDCl3): ¤ 17.77, 20.96, 25.74, 33.91, 123.48, 128.16,
129.03, 132.20, 135.10, 138.73. HRMS (EI) Found: 160.1254
[M+]; Calcd for C12H16: 160.1252.
1.54 (s, 3H), 5.14 (d, J = 17.5 Hz, 1H), 5.25 (d, J = 11.0 Hz, 1H),
6.74 (dd, J = 17.5, 11.0 Hz, 1H), 7.20Í7.24 (m, 1H), 7.29Í7.33 (m,
2H), 7.46Í7.48 (m, 2H); 13C NMR (CDCl3): ¤ 20.14, 25.84, 26.05,
51.18, 74.50, 114.43, 126.14, 127.65, 128.47, 143.58, 144.99.
HRMS (FAB) Found: 189.1280 [M Õ H]+; Calcd for C13H17O:
189.1279.
(E)-1-(3,4-Dimethyl-2-pentenyl)naphthalene (9a): IR (neat)
1
2961, 1506 cmÕ1; H NMR (CDCl3): ¤ 1.03 (d, J = 6.5 Hz, 6H),
1.77 (s, 3H), 2.29Í2.34 (m, 1H), 3.79 (d, J = 7.0 Hz, 2H), 5.04Í
5.44 (m, 1H), 7.33Í7.35 (m, 1H), 7.39Í7.42 (m, 1H), 7.47Í7.53
(m, 2H), 7.71Í7.73 (m, 1H), 7.85Í7.87 (m, 1H), 8.02Í8.04 (m,
1H); 13C NMR (CDCl3): ¤ 13.65, 21.45, 31.46, 36.82, 120.34,
124.05, 125.41, 125.47, 125.61, 125.64, 126.51, 128.62, 132.13,
133.81, 137.86, 142.25. HRMS (EI) Found: 224.1566 [M+]; Calcd
for C17H20: 224,1565.
(E)-1-(3-Phenyl-2-butenyl)naphthalene (9b): IR (neat) 3054,
1507 cmÕ1; 1H NMR (CDCl3): ¤ 2.25 (s, 3H), 4.01 (d, J = 7.0 Hz,
2H), 6.04Í6.08 (m, 1H), 7.21Í7.26 (m, 1H), 7.29Í7.34 (m, 2H),
7.40Í7.44 (m, 4H), 7.49Í7.56 (m, 2H), 7.75Í7.77 (m, 1H), 7.88Í
7.90 (m, 1H), 8.07Í8.09 (m, 1H); 13C NMR (CDCl3): ¤ 16.06,
32.51, 123.94, 125.54, 125.63, 125.71, 125.80, 125.89, 126.61,
126.74, 126.84, 128.17, 128.71, 132.06, 133.88, 135.78, 137.03,
143.47. HRMS (EI) Found: 258.1404 [M+]; Calcd for C20H18:
258.1409.
4-(3-Methyl-2-butenyl)styrene (5g):
IR (neat) 1684,
1558 cmÕ1; H NMR (CDCl3): ¤ 1.77 (s, 3H), 1.80 (s, 3H), 3.38
(d, J = 7.5 Hz, 2H), 5.23 (d, J = 11.0 Hz, 1H), 5.35Í5.39 (m, 1H),
5.75 (d, J = 18.0 Hz, 1H), 6.74 (dd, J = 18.0, 11.0 Hz, 1H), 7.19
(d, J = 8.0 Hz, 2H), 7.38 (d, J = 8.0 Hz, 2H); 13C NMR (CDCl3): ¤
17.79, 25.73, 34.07, 112.85, 122.99, 126.21, 128.42, 132.58,
135.16, 136.67, 141.53. Found: C, 90.38; H, 9.58%. Calcd for
C13H16: C, 90.64; H, 9.36%.
1
Methyl 2-(3-Methyl-2-butenyl)phenyl Ketone (5k): IR (neat)
1
1684, 1253 cmÕ1; H NMR (CDCl3): ¤ 1.70 (s, 3H), 1.72 (s, 3H),
2.56 (s, 3H), 3.58 (d, J = 7.0 Hz, 2H), 5.22Í5.26 (m, 1H), 7.24Í
7.29 (m, 2H), 7.37Í7.40 (m, 1H), 7.59 (dd, J = 7.5, 1.5 Hz, 1H);
13C NMR (CDCl3): ¤ 17.90, 25.73, 29.96, 32.31, 123.02, 125.68,
128.62, 130.62, 131.27, 132.75, 138.33, 141.35, 202.61. HRMS
(EI) Found: 188.1195 [M+]; Calcd for C13H16O: 188.1201.
3-(3-Methyl-2-butenyl)pyridine (5l): IR (neat) 2977, 1576,
1
1423, 1027 cmÕ1; H NMR (CDCl3): ¤ 1.72 (s, 3H), 1.75 (s, 3H),
This work was supported by Grants-in-Aid for Scientific
Research and GCOE Research from MEXT and JSPS. M.I.
thanks JSPS for financial support. H.Y. acknowledges financial
support through Eisai Award of Synthetic Organic Chemistry,
Japan, and from Kyoto University. We are grateful to Professor
Hans-Joachim Knölker (Technische Universität Dresden) for
fruitful discussion.
3.34 (d, J = 7.5 Hz, 2H), 5.27Í5.30 (m, 1H), 7.19Í7.21 (m, 1H),
7.47Í7.49 (m, 1H), 8.42Í8.44 (m, 2H); 13C NMR (CDCl3): ¤
17.85, 25.69, 31.50, 121.76, 123.29, 129.79, 133.76, 135.77,
147.11, 149.82. HRMS (EI) Found: 147.1046 [M+]; Calcd for
C10H13N: 147.1048.
2,3,3,4-Tetramethyl-4-penten-2-ol (6): IR (neat) 3447, 2978,
1377 cmÕ1; 1H NMR (CDCl3): ¤ 1.13 (s, 6H), 1.19 (s, 6H), 1.87 (s,
3H), 4.86 (s, 1H), 5.01 (s, 1H); 13C NMR (CDCl3): ¤ 23.57, 23.72,
25.88, 45.67, 74.27, 113.47, 151.58. HRMS (EI) Found: 125.1334
[M Õ OH]+; Calcd for C9H17: 125.1330.
References
1
For reviews: a) H.-J. Knölker, K. R. Reddy, Chem. Rev.
1-(2,3-Dimethyl-2-butenyl)naphthalene (7a): IR (neat) 1505,
2002, 102, 4303. b) S. Tahara, R. K. Ibrahim, Phytochemistry
1995, 38, 1073.
1
1380, 1202 cmÕ1; H NMR (CDCl3): ¤ 1.66 (s, 3H), 1.81 (s, 3H),
1.84 (s, 3H), 3.78 (s, 2H), 7.26Í7.27 (m, 1H), 7.41Í7.44 (m, 1H),
7.49Í7.55 (m, 2H), 7.73Í7.75 (m, 1H), 7.88Í7.90 (m, 1H), 8.07Í
8.09 (m, 1H); 13C NMR (CDCl3): ¤ 18.67, 20.57, 20.71, 36.95,
123.56, 125.05, 125.35, 125.46, 125.61, 125.65, 126.39, 126.65,
128.64, 132.58, 133.73, 136.18. Found: C, 91.41; H, 8.75%. Calcd
for C16H18: C, 91.37; H, 8.63%.
2
a) H.-J. Knölker, W. Fröhner, Synlett 1997, 1108. b) W.
Fröhner, K. R. Reddy, H.-J. Knölker, Heterocycles 2007, 74, 895.
c) H.-J. Knölker, Chem. Lett. 2009, 38, 8.
3
Selected examples: a) K. Mizuno, M. Ikeda, Y. Otsuji,
Tetrahedron Lett. 1985, 26, 461. b) K. Nakanishi, K. Mizuno, Y.
Otsuji, Bull. Chem. Soc. Jpn. 1993, 66, 2371. c) Y.-S. Jung, B.-Y.
Joe, C.-M. Seong, N.-S. Park, Bull. Korean Chem. Soc. 2000, 21,
463.
Ethyl 4-(2,3-Dimethyl-2-butenyl)benzoate (7c):
IR (neat)
1718, 1275, 1106 cmÕ1; H NMR (CDCl3): ¤ 1.38 (t, J = 7.0 Hz,
3H), 1.58 (s, 3H), 1.74 (s, 3H), 1.78 (s, 3H), 3.50 (s, 2H), 4.36 (q,
J = 7.0 Hz, 2H), 7.20 (d, J = 8.0 Hz, 2H), 7.94 (d, J = 8.0 Hz,
2H); 13C NMR (CDCl3): ¤ 14.35, 18.39, 20.61, 20.70, 40.19,
60.71, 125.58, 126.55, 128.03, 128.36, 129.55, 146.62, 166.72.
Found: C, 77.41; H, 8.71%. Calcd for C15H20O2: C, 77.55; H,
8.68%.
1
4
Y. Hatanaka, K. Goda, T. Hiyama, Tetrahedron Lett. 1994,
35, 6511.
5
a) S. Hayashi, K. Hirano, H. Yorimitsu, K. Oshima, J. Am.
Chem. Soc. 2006, 128, 2210. b) M. Iwasaki, S. Hayashi, K. Hirano,
H. Yorimitsu, K. Oshima, J. Am. Chem. Soc. 2007, 129, 4463.
c) M. Iwasaki, S. Hayashi, K. Hirano, H. Yorimitsu, K. Oshima,
Tetrahedron 2007, 63, 5200. d) S. Hayashi, K. Hirano, H.
Yorimitsu, K. Oshima, J. Am. Chem. Soc. 2007, 129, 12650. e) H.
Yorimitsu, K. Oshima, J. Synth. Org. Chem., Jpn. 2008, 66, 332.
2,3-Dimethyl-3-(1-methylethyl)-4-penten-2-ol (8a): IR (neat)
1
3566, 2979, 1373 cmÕ1; H NMR (CDCl3): ¤ 0.83 (d, J = 6.5 Hz,
3H), 0.96 (s, 3H), 0.98 (d, J = 6.5 Hz, 3H), 1.19 (s, 3H), 1.23 (s,
3H), 1.90 (m, 1H), 5.03 (d, J = 17.5 Hz, 1H), 5.26 (d, J = 11.0 Hz,
1H), 5.88 (dd, J = 17.5, 11.0 Hz, 1H); 13C NMR (CDCl3): ¤ 11.86,
19.27, 20.23, 26.24, 27.30, 32.37, 49.70, 74.84, 114.51, 144.53.
HRMS (EI) Found: 139.1489 [M Õ OH]+; Calcd for C10H19:
139.1487.
6
In the reactions in Table 1, the use of aryl bromides or
iodides generally resulted in lower yields. Excessively smooth
oxidative addition would disorder the catalytic cycle.
7
Reviews for microwave-assisted organic reactions: a)
Microwave Assisted Organic Synthesis, ed. by J. Tierney, P.
Lidström, Blackwell Publishing, Victoria, 2005. b) H. Tokuyama,
M. Nakamura, J. Synth. Org. Chem., Jpn. 2005, 63, 523. c) A. de la
2,3-Dimethyl-3-phenyl-4-penten-2-ol (8b): IR (neat) 3566,
1
2981, 1373 cmÕ1; H NMR (CDCl3): ¤ 1.13 (s, 3H), 1.18 (s, 3H),

M. Iwasaki et al.
Bull. Chem. Soc. Jpn. Vol. 82, No. 2 (2009)
253
Hoz, Á. Diaz-Ortiz, A. Moreno, Chem. Soc. Rev. 2005, 34, 164.
d) C. O. Kappe, Angew. Chem., Int. Ed. 2004, 43, 6250. e) P.
Lidström, J. Tierney, B. Wathey, J. Westman, Tetrahedron 2001,
57, 9225. f) D. M. P. Mingos, D. R. Baghurst, Chem. Soc. Rev.
1991, 20, 1.
9
K. Lee, J. Lee, P. H. Lee, J. Org. Chem. 2002, 67, 8265.
10 A. V. Malkov, S. L. Davis, I. R. Baxendale, W. L. Mitchell,
P. Kočovský, J. Org. Chem. 1999, 64, 2751.
11 S. Knapp, J. Albaneze, H. J. Schugar, J. Org. Chem. 1993,
58, 997.
8
W. Heitz, W. Brügging, L. Freund, M. Gailberger, A.
12 P. H. Lee, S.-Y. Sung, K. Lee, Org. Lett. 2001, 3, 3201.
13 E. Shirakawa, G. Takahashi, T. Tsuchimoto, Y. Kawakami,
Chem. Commun. 2002, 2210.
Greiner, H. Jung, U. Kampschulte, N. Nießner, F. Osan, H.-W.
Schmidt, M. Wicker, Makromol. Chem. 1988, 189, 119.