Synthesis of aryl-substituted naphthalenes by chemoselective Suzuki-Miyaura reactions of bromo-trifluoromethanesulfonyloxy-naphthalenes. Influence of steric and electronic parameters

Article abstract of DOI:10.1016/j.tet.2012.05.026

Chemoselective Suzuki-Miyaura reactions of 2-bromo-1- (trifluoromethanesulfonyloxy)naphthalene, 1-bromo-2- (trifluoromethanesulfonyloxy) naphthalene and 2-acetyl-4-bromo-1- (trifluoromethanesulfonyloxy)naphthalene, which are all readily available from the corresponding tetralone derivatives, afforded a variety of mono- and diarylnaphthalenes. The reactions generally proceed with excellent chemoselectivity in favour of the bromide position, no matter whether the bromide is located at position 1 or 2 of the naphthalene or whether the carbon attached to the triflate group is electronically more deficient by the presence of a neighbouring acetyl group.

Full text of DOI:10.1016/j.tet.2012.05.026

Tetrahedron 68 (2012) 6305e6313
Contents lists available at SciVerse ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Synthesis of aryl-substituted naphthalenes by chemoselective SuzukieMiyaura
reactions of bromo-trifluoromethanesulfonyloxy-naphthalenes. Influence of steric
and electronic parameters
,
,b,
Zahid Hassan a b, Munawar Hussain a, Alexander Villinger a, Peter Langer a
*
a
€
€
Institut fur Chemie, Universitat Rostock, Albert Einstein Str. 3a, 18059 Rostock, Germany
Leibniz-Institut fur Katalyse an der Universitat Rostock e.V., Albert Einstein Str. 29a, 18059 Rostock, Germany
b
€
€
a r t i c l e i n f o
a b s t r a c t
Article history:
Chemoselective SuzukieMiyaura reactions of 2-bromo-1-(trifluoromethanesulfonyloxy)naphthalene, 1-
bromo-2-(trifluoromethanesulfonyloxy) naphthalene and 2-acetyl-4-bromo-1-(trifluoromethanesulfony
loxy)naphthalene, which are all readily available from the corresponding tetralone derivatives, afforded
a variety of mono- and diarylnaphthalenes. The reactions generally proceed with excellent chemo-
selectivity in favour of the bromide position, no matter whether the bromide is located at position 1 or 2
of the naphthalene or whether the carbon attached to the triflate group is electronically more deficient
by the presence of a neighbouring acetyl group.
Received 5 February 2012
Received in revised form 23 April 2012
Accepted 7 May 2012
Available online 19 May 2012
Keywords:
Catalysis
Palladium
Ó 2012 Elsevier Ltd. All rights reserved.
Tetralone
SuzukieMiyaura reaction
Naphthalene
Naphthaquinones
Chemoselectivity
Me OH
NH
1. Introduction
Arylated naphthalenes occur in a wide range of pharmacologi-
cally active natural products. Examples include the naph-
thylisoquinolines, such as the michellamines, such as 1 (Chart 1),
which exhibit anti-malarial and anti-HIV activity.1e3 2-Arylated
naphthalenes can be regarded as rigid stilbene derivatives. The ri-
gidity can be advantageous with regard to biological activity. For
example, the stilbene resveratrol (2) is a natural product, which
shows antitumour activity. However, the applicability of the mole-
cule is limited by its chemical and metabolic instability.4,5 Naph-
thalene derivatives have been proved very good activity against
human breast cancer cell line B with good bioavailability and sta-
bility. It has been also reported that aryl-substituted naphthalenes
can be efficiently used as fungicides.6 1,2-Diphenylnaphthalenes are
Me
Me
OH
OH OMe
OMe OH
HO
Me
Me
NH
OH Me
OH
OH
1
synthetically available by reaction of a-phenyltetralone with phenyl
OH
OH
magnesium bromide and subsequent elimination.7 An alternative
approach to arylated naphthalenes relies on palladium catalyzed
cross-coupling reactions of brominated naphthalenes and a number
of mono-coupling reactions have been reported.3 This approach
HO
HO
3
2
Chart 1. Pharmacologically important naphthalene derivatives.
heavily relies on the availability of the starting materials and on the
fact that the bromination of naphthalenes usually occurs at
* Corresponding author. E-mail address: peter.langer@uni-rostock.de (P. Langer).
0040-4020/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2012.05.026

6306
Z. Hassan et al. / Tetrahedron 68 (2012) 6305e6313
position 1. In recent years, site-selective cross-coupling reactions of
polyhalogenated substrates have been studied.8,9 Arenes
containing both a bromide and a triflate group represent interesting
substrates for chemoselective cross-coupling reactions and it is
known that several parameters influence the selectivity of such re-
actions.10 It occurred to us that naphthalenes containing both
a bromide and a triflate group might be attractive substrates for
chemoselective cross-coupling reactions as they are readily
available from the corresponding tetralones. Recently, we
have reported chemoselective SuzukieMiyaura reactions of
2-bromo-1-(trifluoromethanesulfonyloxy)naphthalene.11 Herein,
we report the extension of our concept to 1-bromo-2-(tri-
fluoromethanesulfonyloxy)naphthalene and to 2-acetyl-4-bromo-
1-(trifluoromethanesulfonyloxy)naphthalene. Our results show
that the reactions generallyproceedwith excellentchemoselectivity
in favour of the bromide position, no matter whether the bromide is
located at position 1 or 2 of the naphthalene or whether the carbon
attached to the triflate group is electronically more deficient by the
presence of a neighbouring acetyl group. The reactions provide
a convenient approach to various arylated naphthalene derivatives,
which are not readily available by other methods.
OTf
Ar
Br
Ar
ArB(OH)2
i
6
8a-c
Scheme 2. Synthesis of 8aec. Conditions: i,
6 (1.0 equiv), ArB(OH)2 (2.2 equiv),
Pd(PPh3)4 (5 mol %), K3PO4 (3.0 equiv), dioxane, 110 ꢀC, 4 h.
The SuzukieMiyaura reaction14 of 6 with arylboronic acids 7
(2.2 equiv) provided the 1,2-diarylnaphthalenes 8aec in 62e94%
yield (Scheme 2, Table 1). Both electron-poor and electron-rich
arylboronic acids could be successfully employed. Better yields
were observed with electron-poor arylboronic acids as compared to
electron-rich arylboronic acids. The best yields were obtained using
Pd(PPh3)4 (5 mol %) as the catalyst and K3PO4 (3.0 equiv) as the
base. 1,4-Dioxane was used as solvent and reactions were carried
out at 110 ꢀC.
Table 1
Synthesis of 1,2-diarylnaphthalenes 8aec
7,8
Ar
% (8)a
a
b
c
2-(MeO)C6H4
4-MeC6H4
4-ClC6H4
62
79
94
2. Results and discussion
a
Yields of isolated compounds.
In 2005, Bekaert et al. described12 the selective synthesis of 2-
bromonaphth-1-ol (5) by reaction of 1-tetralone (4) with N-
methylpyrrolidin-2-one hydrotribromide (MPHT, [NMP]2HBr3). We
have found an alternative approach to 5, which is based on the
bromination13 of 4 using NBS (2.2 equiv) and (PhCOO)2 (5 mol %)
(Scheme 1). Inexpensive reagents are used and the product is
obtained in good yield (84%). The structure of 5 was confirmed by
2D NMR techniques (HMBC and NOESY) (Fig. 1). It is noteworthy
that, although free radical conditions were applied, bromination at
position 4 was not observed. However, by increasing the amount of
NBS to up 4.0 equiv, further bromination was observed at C-4 to
give a small amount of 2,4-dibromonaphthalen-1-ol (10%). 2-
Bromonaphth-1-ol (5) was transformed to its triflate 6 in very
good yield 92% (Scheme 2).
The structures of 8b and 8c were confirmed independently by X-
ray crystallography (Figs. 2 and 3).15
O
OH
Br
i
4
5 (84%)
OTf
ii
Br
6 (92%)
Scheme 1. Synthesis of 5 and 6. Conditions: i, 4 (1.0 equiv), NBS (2.2 equiv), (PhCOO)2
(5 mol %), benzene, reflux, 5 h; ii, 5 (1.0 equiv), Tf2O (1.2 equiv), pyridine (2.0 equiv),
CH2Cl2, 20 ꢀC, 12 h.
Fig. 2. Crystal structure of 8b.
The SuzukieMiyaura reaction of 6 with arylboronic acids 7
(1.0 equiv) afforded the 2-arylnaphth-1-yl-trifluoromethanesulf
onates 9aee in 60e88% yields (Scheme 3, Table 2). The reactions
proceeded with very good chemoselectivity in favour of the bro-
mide position, while the triflate remained unattacked. During the
optimization, it proved to be important to use exactly equimolar
quantities of the arylboronic acid and Pd(PPh3)4 (5 mol %) as the
catalyst. The temperature played an imperative role as well. A good
selectivity was attained only when the reaction was carried out at
90 ꢀC (instead of 110 ꢀC) because the reaction of the triflate was
slow at this temperature. The reactions were successful for both
electron-rich and electron-poor arylboronic acids, but again
electron-poor boronic acids provided better yields.
H
OH
H
H
Br
H
H
H
Fig. 1. Important HMBC (single pointed arrow), NOESY (dashed arrow) and COSY
(double pointed arrow) correlations of compound 5.

Z. Hassan et al. / Tetrahedron 68 (2012) 6305e6313
6307
The SuzukieMiyaura reaction of 9aee with arylboronic acids 7
(1.1 equiv) afforded the 1,2-diarylnaphthalenes 10aee containing
two different aryl groups (Scheme 4, Table 3). The reactions were
carried out at 110 ꢀC. The application of a one-pot synthesis of
products 10 by sequential addition of two different arylboronic
acids to 6 resulted in a decrease of the yield (with respect to the
stepwise protocol). Therefore, this strategy was not further studied.
Ar2
OTf
Ar1
Ar1
Ar2B(OH)2
i
9a-e
10a-e
Scheme 4. Synthesis of 10aee. Conditions: i, 9aee (1.0 equiv), Ar2B(OH)2 (1.1 equiv),
Pd(PPh3)4 (5 mol %), K3PO4 (1.5 equiv), dioxane, 110 ꢀC, 4 h.
Table 3
Synthesis of 10aee
10
7
9
Ar1
Ar2
% (10)a
a
b
c
d
e
j
i
g
a
h
a
b
c
d
e
2-(MeO)C6H4
4-MeC6H4
4-ClC6H4
C6H5
4-tBuC6H4
66
65
72
69
77
2,5-(MeO)2C6H3
3,5-(Me)2C6H3
2-(MeO)C6H4
3-(Me)C6H4
Fig. 3. Crystal structure of 8c.
4-FC6H4
a
Yields of isolated compounds.
OTf
OTf
Ar1
Ar1 B(OH)2
Br
The structure of 10d was independently confirmed by X-ray
crystallography (Fig. 5).15
i
6
9a-e
Scheme 3. Synthesis of 9aee. Conditions: i, 6 (1.0 equiv), Ar1B(OH)2 (1.0 equiv),
Pd(PPh3)4 (5 mol %), K3PO4 (1.5 equiv), dioxane, 90 ꢀC, 4 h.
Table 2
Synthesis of 9aee
7
9
Ar1
% (9)a
a
b
c
d
e
a
b
c
d
e
2-(MeO)C6H4
4-MeC6H4
4-ClC6H4
C6H5
60
73
88
77
85
4-FC6H4
a
Yields of isolated compounds.
The structure of 9e was independently confirmed by X-ray
crystallography (Fig. 4).15
Fig. 5. Molecular structure of 10c.
Aryl bromides generally undergo SuzukieMiyaura reactions
faster than aryl triflates.10 This reactivity order is different for other
palladium catalyzed cross-coupling reactions. One of the justifica-
tions for, that is, based on the high borane-halide affinity. Never-
theless, other parameters control the selectivity as well.10e To
investigate whether the selectivity for naphthalene 6 is based on
the type of leaving group or on steric effects, we decided to study 1-
bromonaphthalen-2-yl trifluoromethanesulfonate (13), which is an
isomer of 6. Bromination of 2-tetralone (11) with NBS (3.0 equiv)
afforded the known product 12.16 Subsequent reaction with triflic
anhydride provided 13 (Scheme 5).
The SuzukieMiyaura reaction of 13 with arylboronic acids 7
(1.0 equiv) afforded the 1-arylnaphth-2-yl-trifluoromethanesulf
onates 14aee (Scheme 6, Table 4). This proves that the bromine-
halide affinity plays the decisive role to control the selectivity of
Fig. 4. Molecular structure of 9e.

6308
Z. Hassan et al. / Tetrahedron 68 (2012) 6305e6313
Br
OH
O
Br
O
OH
OTf
i
ii
11
13
12
O
O
18
11%
O
Scheme 5. Reaction conditions: i, 11 (1.0 equiv), NBS (3.0 equiv), (PhCOO)2 (5 mol %),
benzene, reflux, 5 h; ii, (1.0 equiv), Tf2O (1.2 equiv), pyridine (2.0 equiv), CH2Cl2, 20 ꢀC, 6 h.
+
OH
i
Br
Ar
16
OTf
OTf
ArB(OH)2
OTf
O
i
Br 87%
17
14 a-e
13
Scheme 6. Synthesis of 14aee. Conditions: i, 13 (1.0 equiv), ArB(OH)2 (1.0 equiv),
Pd(PPh3)4 (5 mol %), K3PO4 (1.5 equiv), dioxane, 90 ꢀC, 4 h.
ii
19
92%
Br
Table 4
Synthesis of 14aee
Scheme 7. Reaction conditions: i, 16 (1.0 equiv), NBS (3.0 equiv), (PhCOO)2 (5 mol %),
benzene, reflux, 4 h;ii,17 (1.0equiv), Tf2O(1.2equiv), pyridine(2.0equiv), CH2Cl2, 20ꢀC, 6h.
7
14
Ar1
(14) %a
b
k
d
e
a
b
c
d
e
4-MeC6H4
2-(MeO)-5-ClC6H4
C6H5
4-FC6H4
3,5-(Me)2C6H3
73
60
74
54
76
g
a
Yields of isolated compounds.
the reactions of compounds 6 and 13. The steric or electronic dif-
ference of positions 1 and 2 of the naphthalene moiety has no
influence.
We have previously reported that the SuzukieMiyaura reaction
of phenyl 1,4-bis(trifluoromethylsulfonyloxy)-2-naphthoate 15
(Fig. 6) proceeds regioselectively at position 1, which is more
electron deficient, but also more sterically hindered, than position
4.17 Therefore, we decided to study SuzukieMiyaura reactions of 2-
acetyl-4-bromonaphthalen-1-yl trifluoromethanesulfonate 19. In
this substrate the reactivity of the triflate group should be en-
hanced, due to the proximity of the electron-withdrawing acetyl
group. 2-Acetyl-3,4-dihydronaphthalen-1(2H)-one 16 is a com-
mercially available substrate, which was successfully brominated
using NBS (3.0 equiv) and (PhCOO)2 (5 mol %) to give a separable
mixture of product 17 (82%) and 18 (11%) (Scheme 7). 1-(4-Bromo-
1-hydroxynaphthalen-2-yl)ethanone (17) was transformed to its
corresponding triflate 19 in high yield 88% (Scheme 7). The struc-
ture of 17 was independently confirmed by X-ray crystal structure
analysis (Fig. 7).
Fig. 7. Crystal structure of 17.
reactions
of
phenyl
1,4-bis(trifluoromethylsulfonyloxy)-2-
naphthoate 15.15 The first attack occurs at the bromide position,
despite the electron deficient character of the triflate located close
to the acetyl group.
OTf
O
OTf
O
ArB(OH)2 (1.0 equiv.)
1st attack
i
OTf
O
Br
Ar
20
19
OPh
ii
ArB(OH)2
(2.2 equiv.)
OTf
Ar
Ar
O
2nd attack
15
Fig. 6. Regioselectivity of the SuzukieMiyaura reactions of 15.
21
Scheme 8. Synthesis of 20a,b and 21a,b. Conditions: i, 19 (1.0 equiv), Ar1B(OH)2
(1.0 equiv), Pd(PPh3)4 (5 mol %), K3PO4 (1.5 equiv), dioxane, 90 ꢀC,
h; ii, 20
The SuzukieMiyaura reaction of 19 with arylboronic acids 7
(2.2 equiv) afforded the 1,2-diarylnaphthalenes 21a,b in 78e85%
yield (Scheme 8, Table 6). The SuzukieMiyaura reaction of 19 with
4
(1.0 equiv), ArB(OH)2 (2.2 equiv), Pd(PPh3)4 (5 mol %), K3PO4 (3.0 equiv), dioxane,
110 ꢀC, 4 h.
arylboronic acids
acetylnaphthalen-1-yl-trifluoromethanesulfonates
7
(1.0 equiv) provided the 4-aryl-2-
20a,b in
Table 5
Synthesis of 20a,b
72e86% yields (Scheme 8, Table 5). The reactions proceeded with
very good chemoselectivity in favour of the bromide position, while
the C-1 triflate remained unattacked. This was confirmed by 2D
NMR experiments of compound 20a (Fig. 8). The regioselectivity
observed is opposite to the one observed for the SuzukieMiyaura
20
7
Ar
% (20)a
a
b
l
c
4-(MeO)C6H4
4-ClC6H5
72
86
a
Yields of isolated compounds.

Z. Hassan et al. / Tetrahedron 68 (2012) 6305e6313
6309
Table 6
Synthesis of 21a,b
4.3. General procedure B for the synthesis of triflate 6, 13 and
19
21
7
Ar
% (21)a
To a solution of 5, 12 or 17 (1.0 equiv) in CH2Cl2 (2.5 mL/mmol)
a
b
l
c
4-MeOC6H4
4-ClC6H4
83
85
was added pyridine (2.0 equiv) at 20 ꢀC under an argon atmo-
sphere. After stirring for 10 min at 0 ꢀC, Tf2O (1.5 equiv) was added.
The mixture was allowed to warm to 20 ꢀC and stirred for further
6 h. The reaction mixture was filtered and the filtrate was con-
centrated in vacuo. The residue was directly purified by chroma-
tography without aqueous work up (flash silica gel, heptane/
EtOAc).
a
Yields of isolated compounds.
OTf
O
H
H
H
H
4.3.1. 2-Bromonaphth-1-yl trifluoromethanesulfonate (6). Starting
with 5 (2.4 g, 10.8 mmol) in CH2Cl2 (25 mL), pyridine (1.8 mL,
21.6 mmol) and Tf2O (2.7 mL, 16.4 mmol), following the general
procedure B, 6 was isolated as a light yellow oil (3.53 g, 92%).
Rf¼0.71 (heptane/EtOAC system; 4:1). 1H NMR (300 MHz, CDCl3):
H
H
H
d
¼7.56e7.69 (m, 4H), 7.83 (d, J¼7.8 Hz, 1H), 8.13 (d, J¼8.1 Hz, 1H).
H
H
19F NMR (282.4 MHz, CDCl3):
d
¼ꢂ73.0. 13C NMR (75.5 MHz, CDCl3):
d
¼114.1 (C), 118.5 (q, JC,F¼321.0 Hz, CF3), 121.2, 127.5 (CH), 127.9 (C),
OCH3
128.1, 128.5, 129.4, 129.9 (CH), 133.7, 142.6 (C). IR (KBr): v¼1589,
1501, 1457 (m), 1408 (s), 1370, 1365 (m), 1203, 1181, 1124 (s), 1032
(m) 1018, 890, 801, 761 (s), 743, 703, 665, 616, 587 (m) cmꢂ1. GC/MS
(EI, 70 eV): m/z (%)¼354 ([M]þ, 100), 223 (52). HRMS (EI, 70 eV):
calcd for C11H6BrF3O3S: 353.9173 [M]þ; found: 353.9171.
Fig. 8. Important HMBC (single headed arrows), NOESY (dashed arrows) and COSY
(double headed arrows) correlations of 20a.
3. Conclusions
In conclusion, we have reported chemoselective Suzu-
kieMiyaura reactions of 2-bromo-1-(trifluoromethanesulfonyloxy)
naphthalene, 1-bromo-2-(trifluoromethanesulfonyloxy)naphtha-
lene and 2-acetyl-4-bromonaphthalen-1-yl trifluoromethanesulf
onate. For all substrates the first attack was observed at the bro-
minated carbon (CeBr) while the triflate was attacked later on. The
strategy outlined herein provides a convenient approach to 1,2-
diarylnaphthalenes and 2-acetyl 1,4-diarylnaphthalenes, which
are not readily available by other methods.
4.4. General procedure C for SuzukieMiyaura reactions
A 1,4-dioxane (5 mL) solution of K3PO4 (1.5 equiv per cross-
coupling step), Pd(PPh3)4 (5 mol %) and arylboronic acid 7
(1.0e1.1 equiv per cross-coupling step) was stirred at 90e110 ꢀC for
4 h. After cooling to 20 ꢀC, the organic layer was dried (Na2SO4),
filtered and the filtrate was concentrated in vacuo without aqueous
workup. The residue was purified by column chromatography
(flash silica gel, heptane/EtOAc 9:1).
4. Experimental section
4.4.1. 1,2-Bis(2-methoxyphenyl)naphthalene (8a). Starting with 6
(258 mg, 0.73 mmol), 2-methoxyphenylboronic acid (244 mg,
1.61 mmol), Pd(PPh3)4 (42 mg, 5 mol %), K3PO4 (464 mg, 2.19 mmol)
and 1,4-dioxane (5 mL), following general procedure C, 8a was iso-
lated as a light yellow solid (154 mg, 62%), mp 105e107 ꢀC. 1H NMR
4.1. General procedure A for the synthesis of 5, 12 and 17
A benzene suspension (30 mL) of 1-tetralone 4, 11, 16 (1.0 equiv),
N-bromosuccinimide (NBS) (2.2 equiv) and (PhCOO)2 (5 mol %) was
refluxed under Argon atmosphere for 4 h and then cooled to 20 ꢀC.
To the reaction mixture was added triethylamine (1 mL) and the
solvent was removed in vacuo. The reaction mixture was diluted
with water and extracted with CH2Cl2 (3ꢁ25 mL). The combined
organic layers were dried (Na2SO4), filtered and the filtrate was
concentrated in vacuo. The residue was purified by flash chroma-
tography (silica gel, heptane/EtOAc) to give 5, 12 and 17.
(300 MHz, CDCl3):
d
¼3.46 (s, 3H, OCH3),3.52 (s, 3H, OCH3),
6.64e6.78 (m, 4H), 6.96e7.13 (m, 4H), 7.23e7.29 (m, 1H), 7.33e7.38
(m, 1H), 7.43 (d, J¼8.4 Hz, 2H), 7.76 (d, J¼8.3 Hz, 2H). 13C NMR
(75.5 MHz, CDCl3):
d
¼55.1 (OCH3), 55.2 (OCH3), 110.1, 110.2, 111.1,
119.6, 119.7, 120.3, 125.3, 125.7, 126.6, 127.1, 127.9, 128.1, 128.4, 128.6
(CH), 131.1, 131.4, 132.6, 132.8, 135.2, 135.9, 156.4, 157.3 (C). IR (KBr):
v¼3060, 3026, 2940, 2837 (m), 1605, 1597, 1581, 1495, 1465, 1436,
1405 (s), 1343, 1296, 1270, 1254 (m), 1201, 1132, 1079, 1048, 1026,
1007, 895, 866, 812, 748, 708, 686, 634, 602, 588, 574 (s) cmꢂ1
.
4.2. Synthesis of 2-bromonaphth-1-ol (5)
GCeMS (EI, 70 eV): m/z (%)¼341 (Mþ, 98), 309 (57), 234 (47). HRMS
(EI, 70 eV): calcd for C24H20O2 [M]þ: 340.1534; found: 340.1531.
Starting with 1-tetralone (4) (1.8 mL, 13.7 mmol), N-bromo-
succinimide (NBS) (5.4 g, 30.2 mmol) and (PhCOO)2 (0.17 g,
5 mol %), following general procedure A, 5 was isolated as colourless
4.4.2. 1,2-Bis(4-methylphenyl)naphthalene (8b). Starting with
6
(258 mg, 0.73 mmol), p-tolylboronic acid (219 mg, 1.61 mmol),
Pd(PPh3)4 (42 mg, 5 mol %), K3PO4 (464 mg, 2.19 mmol) and 1,4-
dioxane (5 mL), following the general procedure C, 8b was iso-
lated as a white crystalline solid (177 mg, 79%), mp 103e105 ꢀC. 1H
solid (2.57 g, 84%). 1H NMR (250 MHz, CDCl3):
d
¼5.89 (s, 1H, OH),
7.24 (d, J¼8.8 Hz, 1H), 7.38e7.46 (m, 3H), 7.66e7.75 (m, 1H),
8.12e8.19 (m, 1H). 13C NMR (75.5 MHz, CDCl3):
¼104.0 (C), 121.3,
d
122.2, 124.1 (CH), 124.4 (C), 124.8, 127.5, 128.3 (CH), 133.7, 148.1 (C).
IR (KBr): v¼3400 (s), 3051, 1958, 1931, 1883, 1877, 1624 (w), 1586,
1574 (m), 1504 (w), 1453, 1396, 1384, 1347, 1240, 1212, 1202, 1140,
1126, 1054, 1021, 876, 856 (m), 829, 792, 768, 736 (s), 716, 641, 600,
561 (m) cmꢂ1. GCeMS (EI, 70 eV): m/z (%)¼222 ([M]þ 98), 115 (92).
HRMS (EI, 70 eV): calcd for C10H7BrO [M]þ 221.9680; found:
221.9679. The spectroscopic data were in agreement with those
reported in the literature.12
NMR (300 MHz, CDCl3):
d
¼2.21 (s, 3H, CH3), 2.28 (s, 3H, CH3), 6.91
(d, J¼8.1 Hz, 2H), 6.96e7.03 (m, 6H), 7.26e7.31 (m, 1H), 7.41 (d,
J¼8.4 Hz, 2H), 7.54 (d, J¼8.4 Hz, 1H), 7.80 (d, J¼8.3 Hz, 2H). 13C NMR
(62.9 MHz, CDCl3):
d
¼21.1, 21.3 (2-CH3), 125.2, 126.1, 126.9, 127.3,
127.8, 128.4, 128.5, 128.6, 130.1, 131.2 (CH), 132.7, 132.9, 135.6, 136.1,
136.2, 137.5, 138.2, 139.2 (C). IR (KBr): v¼3051, 3028, 2918, 2862
(m), 1513, 1498, 1425, 1415, 1336, 1308, 1265, 1242,1208, 1222, 1208,
1110,1089,1023,1008, 958 (m), 807, 790, 783, 749, 722, 683 (s), 589,

6310
Z. Hassan et al. / Tetrahedron 68 (2012) 6305e6313
573, 552 (m) cmꢂ1. GCeMS (EI, 70 eV): m/z (%)¼308 (Mþ, 100), 293
(34), 178 (27), 252 (15), 138 (25). HRMS (EI, 70 eV): calcd for C24H20
[M]þ: 308.1559; found: 308.1558. Anal. Calcd for C, 93.46; H, 6.54;
found: C, 93.41; H, 6.52.
was isolated as a yellow solid (248 mg, 88%), mp 82e84 ꢀC. 1H NMR
(300 MHz, CDCl3):
d
¼7.38e7.41 (m, 5H), 7.51e7.56 (m,1H), 7.57e7.63
(m, 1H), 7.84 (dd, J¼8.1, 3.2 Hz, 2H), 8.09 (d, J¼8.4 Hz, 1H). 19F NMR
(282.4 MHz, CDCl3):
d
¼ꢂ73.8.13C NMR (62.9 MHz, CDCl3):
¼117.1 (q,
d
JC,F¼263.0 Hz, CF3), 120.6 (CH), 126.3 (C), 126.4, 126.9, 127.0, 127.1,
127.6, 127.8, 130.1 (CH), 130.6, 133.1, 133.6, 133.8, 140.8 (C). IR (KBr):
v¼3073, 2954, 2922, 2852 (m), 1493, 1402, 1341, 1240, 1212, 1145,
1130, 1094 (s), 1028, 1018, 1006 (m), 894, 864, 837, 811, 765, 750 (s),
734, 698, 680, 634, 626, 597, 574, 549, 538 (m) cmꢂ1. GCeMS (EI,
70 eV): m/z (%)¼386 (Mþ, 83), 253 (49), 218 (100),189 (23). HRMS (EI,
70 eV): calcd for C17H10ClF3O3S [M]þ: 385.9985; found: 385.9988.
Anal. Calcd for C, 52.79; H, 2.61; found: C, 52.76; H, 2.58.
4.4.3. 1,2-Bis(4-chlorophenyl)naphthalene (8c). Starting with
6
(258 mg, 0.73 mmol), p-chloroboronic acid (251 mg, 1.61 mmol),
Pd(PPh3)4 (42 mg, 5 mol %), K3PO4 (464 mg, 2.19 mmol) and 1,4-
dioxane (5 mL), following general procedure C, 8c was isolated as
a white crystalline solid (239 mg, 94%), mp 170e180 ꢀC. 1H NMR
(300 MHz, CDCl3):
d
¼6.95e6.98 (m, 2H), 7.01e7.03 (m, 2H),
7.07e7.11 (m, 2H), 7.19e7.22 (m, 2H), 7.30e7.35 (m, 1H), 7.38e7.44
(m, 2H), 7.56 (d, J¼8.5 Hz, 1H), 7.73 (d, J¼3.1 Hz, 1H), 7.89 (d,
J¼3.0 Hz, 1H).13C NMR (62.9 MHz, CDCl3):
d¼126.1, 126.4, 126.6
4.4.7. 2-Phenylnaphthalen-1-yl trifluoromethanesulfonate (9d).
Starting with 6 (258 mg, 0.73 mmol), phenylboronic acid (89 mg,
0.73 mmol), Pd(PPh3)4 (42 mg, 5 mol %), K3PO4 (232 mg, 1.1 mmol)
and 1,4-dioxane (5 mL), following general procedure C, 9c was iso-
lated as a light yellow solid (197 mg, 77%), mp 75e77 ꢀC. 1H NMR
(CH), 127.4 (C), 127.9, 128.1, 128.2, 128.3 (CH), 129.1 (C), 131.3 (CH),
132.4, 132.5 (C), 132.6 (CH), 132.9 (C), 133.1 (CH), 136.3, 137.2, 140.1
(C). IR (KBr): v¼3050, 2923, 2852 (w), 1487, 1459, 1395, 1374, 1259,
1209 (m), 1086, 1013, 961, 801, 840, 824, 810 (s), 752, 739, 730, 718,
679, 657, 636, 608 (m), 573, 559, 540, 531 (s) cmꢂ1. GCeMS (EI,
70 eV): m/z (%)¼348 (Mþ, 100), 278 (58), 138 (36), 69 (26). HRMS
(EI, 70 eV): calcd for C22H14Cl2 [M]þ: 348.0467; found: 348.0466.
Anal. Calcd for C, 75.66; H, 4.04; found: C, 75.64; H, 4.01.
(300 MHz, CDCl3):
d
¼7.34e7.52 (m, 7H), 7.55e7.61 (m,1H), 7.81 (dd,
J¼8.2, 3.4 Hz, 2H), 8.05 (d, J¼8.4 Hz, 1H). 19F NMR (282.4 MHz,
CDCl3):
d
¼ꢂ73.9. 13C NMR (62.9 MHz, CDCl3):
d
¼117.1 (q,
JC,F¼316.2 Hz, CF3), 120.6, 126.1 (CH), 126.3 (C), 126.9, 127.0, 127.3,
127.4, 127.5, 127.6, 128.7 (CH), 131.7, 133.0, 135.3, 140.9 (C). IR (KBr):
v¼2931, 2865 (m), 1578, 1518, 1485, 1437, 1395, 1321 (s), 1253, 1237,
1202, 1198, 1073, 958 (m), 837, 756, 719, 637 (s) cmꢂ1. GCeMS (EI,
70 eV): m/z (%)¼352 (Mþ, 98), 275 (60). HRMS (EI, 70 eV): calcd for
C17H11F3O3S [M]þ: 352.0412; found: 352.0411. Anal. Calcd for C,
56.54; H, 3.45; found: C, 56.52; H, 3.44.
4.4.4. (2-Methoxyphenyl)naphthalen-1-yl trifluoromethanesulfonate
(9a). Starting
with
6
(258
mg,
0.73
mmol),
2-
methoxyphenylboronic acid (111 mg, 0.73 mmol), Pd(PPh3)4
(42 mg, 5 mol %), K3PO4 (232 mg, 1.1 mmol) and 1,4-dioxane (5 mL),
following general procedure C, 9a was isolated as a yellow solid
(167 mg, 60%), mp 73e75 ꢀC. 1H NMR (300 MHz, CDCl3):
d¼3.71 (s,
3H, OCH3), 6.90 (d, J¼8.4 Hz, 1H), 7.01 (td, J¼8.4, 1.2 Hz, 1H),
7.35e7.41 (m, 1H), 7.21 (d, J¼8.4 Hz, 1H), 7.47e7.52 (m, 1H), 7.42 (d,
J¼8.4 Hz,1H), 7.54e7.61 (m,1H), 7.83 (t, J¼8.1 Hz, 2H), 8.14 (d, J¼8.4,
4.4.8. 2-(4-Fluorophenyl)naphthalen-1-yl trifluoromethanesulfonate
(9e). Starting with 6 (258 mg, 0.73 mmol), p-fluorophenylboronic
acid(102mg, 0.73 mmol), Pd(PPh3)4 (42 mg, 5 mol %), K3PO4 (232mg,
1.1 mmol) and 1,4-dioxane (5 mL), following the general procedure C,
9c was isolated as a light yellow solid (229 mg, 85%), mp 75e77 ꢀC.1H
1H). 19F NMR (282.4 MHz, CDCl3):
d
¼ꢂ74.1. 13C NMR (62.9 MHz,
CDCl3):
d
¼55.5 (OCH3), 111.9 (CH), 118.0 (q, JF,C¼316.2 Hz, CF3),
120.6, 121.6 (CH), 126.4, 126.7 (C), 127.4, 127.9, 128.8, 129.2, 129.6,
130.2, 131.8 (CH), 129.8, 134.4, 142.6, 156.9 (C). IR (KBr): v¼3060,
3026, 3004, 2939, 2837 (w) 1605,1597,1581,1494, 1466,1436,1405,
1361, 1343, 1270, 1254 (m), 1200, 1132, 1079, 1048, 1026, 1007, 895,
866, 811, 748 (s), 708, 686, 634, 602, 588, 574 (m) cmꢂ1. GCeMS (EI,
70 eV): m/z (%)¼382 (Mþ, 93), 249 (100), 234 (43), 218 (35), 189
(12). HRMS (EI, 70 eV): calcd for C18H13F3O4S [M]þ: 382.0481;
found: 382.0481. Anal. Calcd for C, 56.54; H, 3.43; found; C, 56.41;
H, 3.19.
NMR (300 MHz, CDCl3):
d
¼7.05e7.15 (m, 2H), 7.38e7.45 (m, 3H),
7.49e7.62 (m, 2H), 7.80e7.59 (m, 2H), 8.09 (d, J¼8.4 Hz,1H). 19F NMR
(282.4 MHz, CDCl3):
d
¼ꢂ113.2, ꢂ74.0. 13C NMR (62.9 MHz, CDCl3):
d¼115.6 (d, JC,F¼21.4 Hz, CH), 117.1 (q, JC,F¼316.2 Hz, CF3), 119.7 (C),
121.7, 127.3, 128.0 (CH), 128.2 (d, JF,C¼2.6 Hz, CH), 128.6, 131.4, 131.6
(CH),132.3,132.4,134.1,141.9 (C),161.9 (d, JF,C¼248.5 Hz, CF). IR (KBr):
v¼2961,1606 (w),1513,1498 (m),1405,1341,1201 (s),1159 (m),1132
(s), 1088, 1018, 1007 (m), 894 (s), 867 (m), 816, 804 (s), 764 (m), 749
(s), 703, 683, 622, 598, 556 (m)cmꢂ1. GCeMS (EI, 70 eV): m/z (%)¼370
(Mþ, 19), 237 (100), 209 (51), 183 (12). HRMS (EI, 70 eV): calcd for
C17H10F4O3S [M]þ: 370.0271; found: 370.0273. Anal. Calcd for C,
55.14; H, 2.72; found: C, 54.11; H, 2.71.
4.4.5. (4-Methylphenyl)naphthalen-1-yl trifluoromethanesulfonate
(9b). Starting with 6 (258 mg, 0.73 mmol), p-tolylboronic acid
(100 mg, 0.73 mmol), Pd(PPh3)4 (42 mg, 5 mol %), K3PO4 (232 mg,
1.1 mmol) and 1,4-dioxane (5 mL), following general procedure C, 9b
was isolated as a brown solid (195 mg, 73%), mp 71e73 ꢀC. 1H NMR
4.4.9. 1-(4-tert-Butylphenyl)-2-(2-methoxyphenyl)naphthalene
(10a). Starting with 9a (100 mg, 0.26 mmol), 4-tert-butylphe-
nylboronic acid (40 mg, 0.31 mmol), Pd(PPh3)4 (15 mg, 5 mol %),
K3PO4 (85 mg, 0.52 mmol) and 1,4-dioxane (5 mL), following gen-
eral procedure C, 10a was isolated as a viscous solid (124 mg, 66%),
(300 MHz, CDCl3):
d
¼2.23 (s, 3H, CH3), 7.21 (d, J¼8.1 Hz, 2H), 7.37 (d,
J¼8.1 Hz, 2H), 7.47 (d, J¼8.4 Hz, 1H), 7.51e7.54 (m, 1H), 7.57e7.62
(m, 1H), 7.83 (dd, J¼8.1, 4.8 Hz, 2H), 8.09 (d, J¼8.4 Hz, 1H). 13C NMR
(62.9 MHz, CDCl3):
d
¼21.1 (CH3), 119.9 (q, JF,C¼314.2 Hz, CF3), 120.6,
1H NMR (300 MHz, CDCl3):
d
¼1.29 (s, 9H, CH3), 3.51 (s, 3H, OCH3),
126.0 (CH), 126.4 (C), 126.8, 126.9, 127.4, 127.5, 128.2, 128.5 (CH),
131.8, 132.4, 132.9, 137.2, 140.9 (C). IR (KBr): v¼3051, 3028, 2918,
2862 (m), 1513, 1498, 1425, 1415, 1336, 1308, 1265, 1242, 1208, 1222,
1208, 1110, 1089, 1023, 1008, 958 (m), 807, 790, 783, 749, 722, 683
(s), 589, 573, 552 (m) cmꢂ1. GCeMS (EI, 70 eV): m/z (%)¼366 (Mþ,
78), 275 (64), 204 (27), 138 (25). HRMS (EI, 70 eV): calcd for C18H13
F3O3S [M]þ: 366.0559; found: 366.0556. Anal. Calcd for C, 59.01; H,
3.58; found: C, 59.02; H, 3.55.
6.96e7.13 (m, 3H), 7.23e7.29 (m, 2H), 7.33e7.37 (m, 1H), 7.39 (d,
J¼8.63 Hz, 2H), 7.43 (d, J¼8.4 Hz, 2H), 7.57 (d, J¼8.61 Hz, 2H), 7.76
(d, J¼8.3 Hz, 2H). 13C NMR (75.5 MHz, CDCl3): ¼30.1 (3-CH3), 33.7
d
(C) 55.2 (OCH3), 116.6, 119.3, 120.3, 125.5, 125.6, 126.2, 127.3, 128.0,
128.2, 128.5, 128.7, 129.3 (CH), 131.4, 131.7, 132.4, 132.7, 134.7, 136.5,
149.4,156.4 (C). IR (KBr): v¼3052, 3016, 2924, 2904, 2873 (m),1625,
1577, 1551, 1493, 1454, 1413 (s), 1296, 1267, 1243 (m), 1172, 1077,
1038, 897, 826, 812, 651, 624, 574 (s) cmꢂ1. GCeMS (EI, 70 eV): m/z
(%)¼366 (Mþ, 98), 335 (64), 278 (58). HRMS (EI, 70 eV): calcd for
C27H26O [M]þ: 366.4136; found: 366.4132.
4.4.6. 2-(4-Chlorophenyl)naphthalen-1-yl trifluoromethanesulfonate
(9c). Starting with 6 (258 mg, 0.73 mmol), phenylboronic acid
(114 mg, 0.73 mmol), Pd(PPh3)4 (42 mg, 5 mol %), K3PO4 (232 mg,
1.1 mmol) and 1,4-dioxane (5 mL), following general procedure C, 9d
4.4.10. 2-(4-Methylphenyl)-1-(2,5-dimethoxyphenyl)naphthalene
(10b). Starting with 9b (100 mg, 0.27 mmol), 2,5-

Z. Hassan et al. / Tetrahedron 68 (2012) 6305e6313
6311
dimethoxyphenylboronic acid (55 mg, 0.30 mmol), Pd(PPh3)4
312 (Mþ, 100), 222 (55), 204 (7). HRMS (EI, 70 eV): calcd for C23H17
F
(16 mg, 5 mol %), K3PO4 (86 mg, 0.41 mmol) and 1,4-dioxane
(5 mL), following general procedure C, 10b was isolated as
a highly viscous oil (62 mg, 65%). 1H NMR (300 MHz, CDCl3):
[M]þ: 312.1314; found: 312.1313.
4.5. Synthesis of 1-bromonaphth-2-ol (12)
d
¼2.21 (s, 3H, CH3), 3.41 (s, 3H, OCH3), 3.57 (s, 3H, OCH3), 6.56 (d,
J¼2.7 Hz, 1H), 6.73e6.74 (m, 2H), 6.91 (d, J¼7.8 Hz, 2H), 7.02 (d,
J¼7.9 Hz, 2H), 7.29e7.32 (m, 1H), 7.34e7.41 (m, 1H), 7.48 (d,
J¼8.4 Hz, 2H), 7.81 (dd, J¼4.7, 4.4 Hz, 2H). 13C NMR (62.9 MHz,
Starting with 1-tetralone (11) (0.6 mL, 4.6 mmol), N-bromo-
succinimide (NBS) (1.8 g, 10.1 mmol) and (PhCOO)2 (0.056 g,
5 mol %), following general procedure A, 12 was isolated as colour-
less solid (0.81 g, 82%). The spectroscopic data were in agreement
with those reported in the literature.15
CDCl3):
d
¼21.7 (CH3), 54.6 (OCH3), 54.8 (OCH3), 110.8, 112.6, 117.1,
124.3, 125.1, 125.6, 126.6, 126.8 (CH), 127.1 (2-CH), 128.0 (2-CH),
128.2 (CH), 128.3, 131.5, 131.7, 132.8, 134.7, 137.8, 138.2, 151.1, 152.2
(C). IR (KBr): v¼2934, 2872 (w), 1476, 1454, 1361, 1259 (m), 1166,
1043, 975, 843, 834 (s), 742, 729, 708, 679, 647, 626 (m), 571, 542,
537 (s) cmꢂ1. GCeMS (EI, 70 eV): m/z (%)¼354 (Mþ, 100), 323 (57),
263 (31), 216 (18). HRMS (EI, 70 eV): calcd for C25H22O2 [M]þ:
354.1623; found: 354.1621. Anal. Calcd for C, 84.72H, 6.26; found:
C, 84.69; H, 6.21.
4.5.1. 1-Bromonaphthalen-2-yl trifluoromethanesulfonate (13).
Starting with 12 (0.80 g, 3.6 mmol) in CH2Cl2 (20 mL), pyridine
(0.5 mL, 7.0 mmol) and Tf2O (0.9 mL, 5.4 mmol), following general
procedure B, 13 was isolated as a light yellow oil (1.20 g, 92%).
4.5.2. 1-p-Tolylnaphthalen-2-yl trifluoromethanesulfonate (14a).
Starting with 13 (70 mg, 0.20 mmol), p-tolylboronic acid (27 mg,
0.20 mmol, 1.0 equiv), Pd(PPh3)4 (12 mg, 5 mol %), K3PO4 (64 mg,
0.30 mmol) and 1,4-dioxane (5 mL), following general procedure C,
14a was isolated as a brown solid (54 mg, 73%), mp 70e72 ꢀC. 1H
4.4.11. 2-(4-Chlorophenyl)-1-(3,5-dimethylphenyl)naphthalene
(10c). Starting with 9d (100 mg, 0.26 mmol), 3,5-
dimethylphenylboronic acid (44 mg, 0.29 mmol), Pd(PPh3)4
(16 mg, 5 mol %), K3PO4 (83 mg, 0.39 mmol) and 1,4-dioxane (5 mL),
following general procedure C, 10d was isolated as a reddish crys-
talline solid (64 mg, 72%), mp 106e109 ꢀC. 1H NMR (300 MHz,
NMR (300 MHz, CDCl3):
d
¼2.33 (s, 3H, CH3), 7.21 (d, J¼8.2 Hz, 2H),
7.24 (d, J¼8.4 Hz, 1H), 7.39e7.46 (m, 1H), 7.49e7.56 (m, 1H), 7.68 (d,
J¼8.4 Hz, 2H), 7.76 ( d, J¼8.5 Hz, 2H), 8.15 ( d, J¼8.5 Hz,1H). 19F NMR
CDCl3):
d
¼2.19 (s, 6H, 2CH3) 6.71 (br s, 2H), 6.84 (br s, 1H), 7.01e7.12
(282.4 MHz, CDCl3):
NMR (62.9 MHz, CDCl3):
d
¼ꢂ73.2. 13C NMR (75.5 MHz, CDCl3):
d
13C
¼
(m, 4H), 7.29e7.35 (m,1H), 7.38e7.44 (m, 2H), 7.42 (d, J¼8.4 Hz,1H),
d
¼21.1 (CH3), 119.9 (q, JF,C¼314.2 Hz, CF3),
7.59 (d, J¼8.4 Hz, 2H). 13C NMR (62.9 MHz, CDCl3):
d¼21.3 (2 CH3),
119.8, 126.8, 127.3, 127.6, 127.7, 128.1 (CH), 128.3 (C), 129.1, 130.6
(CH), 132.8, 132.6, 133.4, 138.3, 144.3 (C). IR (KBr): v¼3019, 2927,
2869 (m), 1541, 1498, 1438, 1423, 1301, 1285, 1245, 1211, 1108, 1093,
125.1 (C), 125.7, 126.2, 127.1, 127.4, 127.7, 127.8, 127.9, 128.4, 129.1,
131.3, 132.1 (CH), 132.1, 132.7, 132.8, 136.7, 137.2, 138.1, 138.4, 140.6
(C). IR (KBr): v¼2978, 2853 (w), 1477, 1458, 1375, 1276, 1254 (m),
1037, 1003, 987, 821, 834, 817 (s), 739, 721, 718, 673, 665, 608 (m),
573, 543, 537 (s) cmꢂ1. GCeMS (EI, 70 eV): m/z (%)¼342 (Mþ, 100),
307 (58), 238 (36). HRMS (EI, 70 eV): calcd for C24H19Cl [M]þ:
342.1271; found: 342.1269. Anal. Calcd for C, 84.26; H, 5.59; found:
C, 84.23; H, 5.58.
1073, 967 (m), 817, 793, 771, 758, 712, 653 (s), 574, 542 (m), cmꢂ1
.
GCeMS (EI, 70 eV): m/z (%)¼366 (Mþ, 98), 275 (57), 217 (44), 138
(37). HRMS (EI, 70 eV): calcd for C18H13F3O3S [M]þ: 366.0519;
found: 366.0516. Anal. Calcd for C, 59.01; H, 3.58; found: C, 59.02;
H, 3.55.
4.5.3. 1-(5-Chloro-2-methoxyphenyl)naphthalen-2-yl
trifluorome
4.4.12. 2-(Phenyl)-1-(2-methoxyphenyl)naphthalene (10d). Starting
with 9c (100 mg, 0.28 mmol), 2-methoxyphenylboronic acid
(48 mg, 0.31 mmol), Pd(PPh3)4 (16 mg, 5 mol %), K3PO4 (89 mg,
0.42 mmol) and 1,4-dioxane (5 mL), following general procedure C,
10c was isolated as a brown highly viscous oil (60 mg, 69%). 1H NMR
thanesulfonate (14b). Starting with 13 (70 mg, 0.20 mmol,
1.0 equiv), 5-chloro-2-methoxyphenylboronic acid (37 mg,
0.20 mmol), Pd(PPh3)4 (12 mg, 5 mol %), K3PO4 (64 mg, 0.30 mmol)
and 1,4-dioxane (5 mL), following general procedure C, 14b was
isolated as a white solid (50 mg, 60%), mp 75e77 ꢀC. 1H NMR
(300 MHz, CDCl3):
d
¼3.39 (s, 3H, OCH3), 6.82e7.21 (m, 4H),
(300 MHz, CDCl3):
d
¼3.69 (s, OCH3), 6.79 (d, J¼8.4 Hz, 2H), 6.98 (d,
7.34e7.45 (m, 6H), 7.47e7.54 (m, 1H), 7.57e7.63 (m, 1H), 7.81e7.85
J¼8.2 Hz, 1H), 7.10e7.11 (m, 1H), 7.16e7.21 (m, 2H), 7.33e7.47 (m,
(m, 2H), 8.09 (d, J¼8.4 Hz, 1H). 13C NMR (62.9 MHz, CDCl3):
d¼54.6
2H), 7.80e7.89 (m, 1H). 19F NMR (282.4 MHz, CDCl3):
NMR (62.9 MHz, CDCl3):
d
¼ꢂ74.5. 13
C
(OCH3), 111.2, 120.7, 121.6 (CH), 124.6 (C), 127.0, 127.8, 128.1, 128.5,
128.6, 129.2, 129.6 (CH), 129.8 (C), 130.2, 131.5, 131.8 (CH), 134.2,
142.6, 156.9 (C). GCeMS (EI, 70 eV): m/z (%)¼310 (Mþ, 98), 279 (53),
233 (69). HRMS (EI, 70 eV): calcd for C23H18O [M]þ: 310.1431;
found: 310.1430. Anal. Calcd for C, 89.00H, 5.85; found: C, 89.01; H,
5.81.
d
¼54.7 (OCH3),117.5 (q, JF,C¼316.2 Hz, CF3),
120.1, 121.3 (CH), 126.1, 126.4 (C), 127.2, 127.6, 128.5, 128.8, 129.2,
130.0, 131.6 (CH), 132.7, 134.0, 137.8, 142.3, 155.1 (C). IR (KBr):
v¼3014, 2941, 2872 (w) 1655, 1572, 1581, 1466, 1436, 1405, 1361,
1343, 1270, 1254 (m), 1200, 1132, 1079, 1048, 1026, 1007, 895, 866,
811, 748 (s), 708, 686, 634, 602, 588, 574 (m) cmꢂ1. GCeMS (EI,
70 eV): m/z (%)¼416 (Mþ, 81), 274 (76), 267 (43),141 (29). HRMS (EI,
70 eV): calcd for C18H12ClF3O4S [M]þ: 416.0135; found: 416.0131.
Anal. Calcd for C, 51.87; H, 2.90; found; C, 51.86; H, 2.88.
4.4.13. 2-(4-Fluorophenyl)-1-(m-tolyl)naphthalene (10e). Starting
with 9e (200 mg, 0.54 mmol), 3-methylphenylboronic acid (81 mg,
0.59 mmol), Pd(PPh3)4 (32 mg, 5 mol %), K3PO4 (173 mg, 0.81 mmol)
and 1,4-dioxane (5 mL), following general procedure C, 10e was
isolated as a colourless solid (130 mg, 77%), mp 109e111 ꢀC. 1H NMR
4.5.4. 1-Phenylnaphthalen-2-yl trifluoromethanesulfonate (14c).
Starting with 13 (86 mg, 0.24 mmol), phenylboronic acid (30 mg,
0.24 mmol, 1.2 equiv), Pd(PPh3)4 (14 mg, 5 mol %), K3PO4 (77 mg,
0.36 mmol) and 1,4-dioxane (5 mL), following general procedure C,
14c was isolated as a white solid (61 mg, 74%), mp 72e74 ꢀC. 1H
(300 MHz, CDCl3):
d
¼2.23 (s, 3H, CH3), 6.75e6.91 (m, 4H),
7.00e7.05 (m, 3H), 7.10 (t, J¼7.4 Hz, 1H), 7.28e7.40 (m, 2H), 7.43 (d,
J¼8.6 Hz, 1H), 7.58 (d, J¼8.5 Hz, 1H), 7.81 (d, J¼8.2 Hz 2H). 19F NMR
(282.4 MHz, CDCl3):
d
¼ꢂ116.6. 13C NMR (75.5 MHz, CDCl3):
d¼114.5
NMR (300 MHz, CDCl3):
d¼7.24e7.34 (m, 3H), 7.49e7.62 (m, 3H),
(d, JC,F¼21.3 Hz, CH), 125.8, 126.3, 126.9, 127.6, 127.8, 127.9, 128.1,
128.5, 131.5, 131.6, 132.1 (CH), 132.7, 132.8, 137.2, 137.4, 137.9, 138.1
(d, JC,F¼3.3 Hz, C), 138.7 (C), 161.5 (d, JC,F¼245.6 Hz, CF). IR (KBr):
v¼3050, 2920 (m), 2852 (w), 1601 (m), 1499 (s), 1457 (m), 1234 (w),
1218 (s), 1155, 1092, 1023 (m), 962 (w), 863, 841 (m), 817, 803, 778,
743, 713, 693 (s), 653, 544 (m) cmꢂ1. GCeMS (EI, 70 eV): m/z (%)¼
7.68 (d, J¼8.4 Hz, 2H), 7.76 ( d, J¼8.5 Hz, 2H), 8.15 ( d, J¼8.5 Hz, 1H).
19F NMR (282.4 MHz, CDCl3):
13C NMR (62.9 MHz, CDCl3):
d
¼ꢂ73.7. 13C NMR (75.5 MHz, CDCl3):
d¼
d
¼117.8 (q, JF,C¼314.2 Hz, CF3), 119.8,
126.8, 127.3, 127.6, 127.7, 128.1, 129.0, 129.3, 130.6 (CH), 132.8, 132.6,
133.4, 135.3, 140.7 (C). IR (KBr): v¼2956, 2891 (m), 1573, 1511, 1483,
1422, 1255, 1219, 1213, 1173, 1133, 983 (m), 819, 781, 784, 765 (s),

6312
Z. Hassan et al. / Tetrahedron 68 (2012) 6305e6313
547, 514 (m), cmꢂ1. GCeMS (EI, 70 eV): m/z (%)¼352 (Mþ, 97), 273
(57), 217 (34). HRMS (EI, 70 eV): calcd for C17H11F3O3S [M]þ:
352.0412; found: 352.0410.
2962, 2929 (m), 1699, 1620, 1594, 1494, 1426, 1403 (s), 1370, 1351,
1318, 1266, 1243 (m), 1203, 1130, 1171, 1037, 867, 818, 760, 720, 647,
629, 603, 571, 551 (s) cmꢂ1. GCeMS (EI, 70 eV): m/z (%)¼396 (Mþ,
97), 265 (95), 248 (20), 237 (73), 128 (36). HRMS (EI, 70 eV): calcd
for C13H8BrF3O4S [M]þ: 395.9273; found: 395.9269. Anal. Calcd for
C, 39.31; H, 2.02; found: C, 39.29; H, 2.01.
4.5.5. 1-(4-Fluorophenyl)naphthalen-2-yl trifluoromethanesulfonate
(14d). Starting with 13 (86 mg, 0.24 mmol), 4-fluorophenylboronic
acid (34 mg, 0.24 mmol, 1.2 equiv), Pd(PPh3)4 (14 mg, 5 mol %),
K3PO4 (77 mg, 0.36 mmol) and 1,4-dioxane (5 mL), following gen-
eral procedure C, 14d was isolated as a solid (70 mg, 54%), mp
4.6.2. 2-Acetyl-4-(4-methoxyphenyl)naphthalen-1-yl trifluorometh
anesulfonate (20a). Starting with 19 (79 mg, 0.20 mmol), 4-
methoxyphenylboronic acid (30 mg, 0.20 mmol), Pd(PPh3)4
(12 mg, 5 mol %), K3PO4 (64 mg, 0.30 mmol) and 1,4-dioxane (5 mL),
following general procedure C, 20a was isolated as a slight brown oil
71e73 ꢀC. 1H NMR (300 MHz, CDCl3):
d
¼7.03e7.11 (m, 2H),
7.36e7.41 (m, 3H), 7.51e7.59 (m, 2H), 7.61e7.64 (m, 2H), 8.11 (d,
J¼8.4 Hz, 1H). 19F NMR (282.4 MHz, CDCl3):
d
¼ꢂ113.1, ꢂ73.9. 13C
NMR (62.9 MHz, CDCl3):
d¼115.3 (d, JC,F¼21.2 Hz, CH), 117.1 (q,
(53 mg, 62%). 1H NMR (300 MHz, CDCl3):
d
¼2.64 (s, 3H, CH3), 3.83
JC,F¼315.7 Hz, CF3), 119.5 (C), 122.0, 127.1, 127.8 (CH), 128.0 (d,
JF,C¼2.4 Hz, CH), 128.2, 130.7, 131.3 (CH), 132.0, 132.2, 133.8, 140.9
(C), 162.1 (d, JF,C¼248.7 Hz, CF). IR (KBr): v¼2926, 1626 (w), 1572,
1521 (m), 1463, 1344, 1227 (s), 1167 (m), 1144 (s), 1081, 1018 (m),
894 (s), 866 (m), 824, 814 (s), 754 (m), 747 (s), 703, 622, 556 (m)
cmꢂ1. GCeMS (EI, 70 eV): m/z (%)¼370 (Mþ, 19), 237 (100), 209 (51),
183 (12). HRMS (EI, 70 eV): calcd for C17H10F4O3S [M]þ: 370.0271;
found: 370.0273.
(s, 3H, OCH3), 6.96e7.01 (m, 2H), 7.18 (s, 1H), 7.31e7.34 (m, 1H),
7.50e7.55 (m, 2H), 7.59e7.64 (m, 1H), 7.87 (d, J¼8.5 Hz, 1H), 8.16 (d,
J¼8.5 Hz, 1H). 19F NMR (282.4 MHz, CDCl3):
d
¼ꢂ72.8. 13C NMR
(75.5 MHz, CDCl3):
d
¼29.7 (CH3), 55.4 (OCH3), 114.1 (CH), 117.5 (q,
JC,F¼321 Hz, CF3), 122.5, 125.0, 126.6 (CH), 126.9 (C), 128.1, 128.7
(CH), 129.5, 130.7 (C), 131.0 (CH), 134.5, 140.9, 141.1, 159.6 (C), 198.3
(CO). IR (KBr): v¼3073, 3003, 2957, 2929, 2838 (m), 1697, 1607,
1572, 1515, 1499, 1456, 1423, 1404, 1366 (s), 1290, 1256 (w), 1244,
1204, 1177, 1149, 1134, 1028 (s), 978, 943, 937, 886 (m), 831, 793,
764, 721, 707, 636, 604, 588, 574 (s) cmꢂ1. GCeMS (EI, 70 eV): m/z
(%)¼424 (Mþ, 81), 291 (98), 277 (17), 263 (36), 235 (12), 149 (29).
HRMS (EI, 70 eV): calcd for C20H15F3O5S [M]þ: 424.0678; found:
424.0668 Anal. Calcd for C, 56.61; H, 3.56; found: C, 56.59; H, 3.54.
4.5.6. 1-(3,5-Dimethylphenyl)naphthalen-2-yl
trifluoromethane
sulfonate (14e). Starting with 13 (86 mg, 0.24 mmol), 3,5-
dimethylphenylboronic acid (43 mg, 0.24 mmol, 1.2 equiv),
Pd(PPh3)4 (14 mg, 5 mol %), K3PO4 (67 mg, 0.36 mmol) and 1,4-
dioxane (5 mL), following general procedure C, 14e was isolated as
a brown solid (73 mg, 76%), mp 81e83 ꢀC. 1H NMR (300 MHz,
4.6.3. 2-Acetyl-4-(4-chlorophenyl)naphthalen-1-yl trifluoromethane
sulfonate (20b). Starting with 19 (79 mg, 0.20 mmol), 4-
chlorophenylboronic acid (31 mg, 0.20 mmol), Pd(PPh3)4 (12 mg,
5 mol %), K3PO4 (64 mg, 0.30 mmol) and 1,4-dioxane (5 mL), fol-
lowing general procedure C, 20b was isolated as a highly viscous oil
CDCl3):
d
¼2.27 (s, 6H, 2CH3) 6.68 (s, 2H), 6.77 (br s, 1H), 7.16e7.21
(m, 3H), 7.33e7.47 (m, 1H), 7.76 (d, J¼8.6 Hz, 2H). 13C NMR
(62.9 MHz, CDCl3):
d¼21.4 (2-CH3), 125.3 (C), 124.9, 126.0, 126.8,
127.1, 127.3, 127.7, 128.0, 128.5, 129.0, 130.7, 132.0, (CH), 132.3, 133.0,
133.3, 136.0, 136.6, 138.0, 138.3, 140.2 (C). IR (KBr): v¼2966, 2873
(w), 1481, 1468, 1355, 1327, 1264, 1244 (m), 1036, 978, 822, 831, 827
(s), 733, 715, 663, 605 (m), 543, 531 (s) cmꢂ1. GCeMS (EI, 70 eV):
m/z (%)¼380 (Mþ, 100), 274 (68), 231 (46). HRMS (EI, 70 eV): calcd
for C19H15F3O3S [M]þ: 380.2821; found: 380.218.
(74 mg, 86%). 1H NMR (300 MHz, CDCl3):
d
¼2.61 (s, 3H, CH3),
6.91e6.97 (m, 2H), 7.13 (s, 1H), 7.28e7.332 (m, 1H), 7.47e7.52 (m,
2H), 7.56e7.61 (m, 1H), 7.81 (d, J¼8.4 Hz, 1H), 8.14 (d, J¼8.4 Hz, 1H).
19F NMR (282.4 MHz, CDCl3):
d
¼ꢂ72.3. 13C NMR (75.5 MHz, CDCl3):
d¼29.4 (CH3), 113.8 (CH), 116.9 (q, JC,F¼321 Hz, CF3), 121.7, 121.8,
121.4 (CH), 125.6 (C), 127.7, 127.9 (CH), 128.2, 129.8 (C), 131.0 (CH),
133.7, 140.0, 141.1, 158.9 (C), 198.0 (CO). IR (KBr): v¼3067, 3023,
2975, 2883 (m), 1687, 1636, 1552, 1423, 1404, 1386 (s), 1266 (w),
1231, 1209, 1176, 1141 (s), 972, 934, 874 (m), 831, 773, 761, 709, 570
(s) cmꢂ1. GCeMS (EI, 70 eV): m/z (%)¼428 (Mþ, 98), 317 (76), 279
(37), 168 (09). HRMS (EI, 70 eV): calcd for C19H12ClF3O4S [M]þ:
428.0156; found: 428.0154. Anal. Calcd for C, 53.22; H, 2.82; found:
C, 53.19; H, 2.79.
4.6. Synthesis of 1-(4-bromo-1-hydroxynaphthalen-2-yl)
ethanone (17)
Starting with 2-acetyl-3,4-dihydronaphthalen-1(2H)-one (16)
(3.00 g, 13.7 mmol), N-bromosuccinimide (NBS) (5.4 g, 30.2 mmol)
and (PhCOO)2 (0.17 g, 5 mol %), following general procedure A, 17
was isolated as green crystalline solid, mp 124e126 ꢀC. 1H NMR
(300 MHz, CDCl3):
(m, 1H), 7.87 (s, 1H), 8.03 (d, J¼8.4 Hz, 1H), 8.38 (d, J¼8.3 Hz, 1H),
13.83 (s, OH). 13C NMR (75.5 MHz, CDCl3):
¼26.8 (CH3), 111.1, 113.9
d
¼2.59 (s, 3H, CH3), 7.47e7.53 (m, 1H), 7.63e7.68
4.6.4. 1-(1,4-Di-p-tolylnaphthalen-2-yl)ethanone
(21a). Starting
d
with 19 (79 mg, 0.20 mmol), p-tolylboronic acid (60 mg,
0.44 mmol), Pd(PPh3)4 (12 mg, 5 mol %), K3PO4 (127 mg, 0.60 mmol)
and 1,4-dioxane (5 mL), following general procedure C, 21a was
isolated as a slight yellow highly viscous oil (60 mg, 85%). 1H NMR
(C), 124.8, 126.41 (CH), 126.7 (C), 127.1, 128.2, 131.2 (CH), 135.7, 161.9,
203.3 (C). IR (KBr): v¼3130, 3071, 3033 (m), 1731, 1712, 1620, 1614,
1574, 1565, 1502, 1447, 1406, 1363, 1314, 1265, 1236, 1211, 1137 (s),
1082,1025, 979, 871, 862, 837, 862, 837 (m), 754, 720, 686, 643, 588,
565 (s) cmꢂ1. GCeMS (EI, 70 eV): m/z (%)¼364 (Mþ, 100), 251 (76),
195 (20), 114 (23). HRMS (EI, 70 eV): calcd for C12H9BrO2 [M]þ:
263.9780; found: 263.9778. Anal. Calcd for C, 54.37; H, 3.42; found:
C, 54.31; H, 3.41.
(300 MHz, CDCl3):
CH3), 7.21e7.27 (m, 6H), 7.33e7.41 (m, 4H), 7.50 (s, 1H), 7.63e7.72
(m,1H), 7.88e7.91 (m,1H). 13C NMR (75.5 MHz, CDCl3):
¼21.2, 21.3,
d
¼2.1 (s, 3H, CH3), 2.3 (s, 3H, CH3), 2.4 (s, 3H,
d
30.8 (CH3), 125.1, 126.2, 126.4, 127.1, 127.6, 129.1, 129.2, 129.9, 130.6
(CH), 132.5, 132.8, 135.3, 137.1, 137.3, 137.6, 137.7, 137.9, 140.1 (C),
204.9 (CO). IR (KBr): 3022, 2921, 2865 (w), 1711 (s), 1591, 1511 (w),
1485, 1378, 1367 (m), 1241, 1220, 1192 (s), 1099, 1020, 926 (m), 814,
746 (s), 687, 595 (m) cmꢂ1. GCeMS (EI, 70 eV): m/z (%)¼350 (Mþ,
99), 259 (66), 91 (07). HRMS (EI, 70 eV): calcd for C26H22O [M]þ:
350.1745; found: 350.1741. Anal. Calcd for C, 89.11; H, 6.33; found: C,
89.09; H, 6.31.
4.6.1. 2-Acetyl-4-bromonaphthalen-1-yl trifluoromethanesulfonate
(19). Starting with 17 (2.00 g, 7.54 mmol) in CH2Cl2 (25 mL), pyr-
idine (1.5 mL, 20 mmol) and Tf2O (1.8 mL), following general pro-
cedure B, 19 was isolated as a light green oil (2.75 g, 88%). 1H NMR
(300 MHz, CDCl3):
d
¼2.59 (s, 3H, CH3), 7.46e7.51 (m, 1H), 7.62e7.71
(m, 2H), 7.92 (s, 1H), 8.11 (d, J¼8.4 Hz, 1H). 19F NMR (282.4 MHz,
CDCl3):
d
¼ꢂ72.7. 13C NMR (75.5 MHz, CDCl3):
d¼29.6 (CH3),117.5 (q,
4.6.5. 1-(1,4-Bis(2-chlorophenyl)naphthalen-2-yl)ethanone
(21b). Starting with 19 (79 mg, 0.20 mmol), 2-chlorophenylboronic
acid (69 mg, 0.44 mmol), Pd(PPh3)4 (12 mg, 5 mol %), K3PO4 (127 mg,
JC,F¼321 Hz, CF3), 121.7 (C), 122.18 (CH), 126.5, 126.6 (C), 127.0, 128.1,
129.2, 130.3 (CH), 133.3, 140.3, 195.6 (C). IR (KBr): v¼3076, 3002,

Z. Hassan et al. / Tetrahedron 68 (2012) 6305e6313
6313
5. Jang, M.; Cai, L.; Udeani, G. O.; Slowing, K. V.; Thomas, C. F.; Beecher, C. W.;
Fong, H. H.; Farnsworth, N. R.; Kinghorn, A. D.; Mehta, R. G.; Moon, R. C.;
Pezzuto, J. M. Science 1997, 275, 218.
0.60 mmol) and 1,4-dioxane (5 mL), following general procedure C,
21b was isolated as a slight yellow highly viscous oil (229 mg, 85%).
1H NMR (300 MHz, CDCl3):
d
¼2.10 (s, 3H, CH3), 7.17e7.21 (m, 1H),
6. (a) Signorelli, P.; Ghidoni, R. J. Nutr. Biochem. 2005, 16, 449; (b) Minutolo, F.; Sala,
G.; Bagnacani, A.; Bertini, S.; Carboni, I.; Placanica, G.; Prota, G.; Rapposelli, S.;
Sacchi, N.; Macchia, M.; Ghadoni, R. J. Med. Chem. 2005, 48, 6783; (c) Viswana-
than, G. S.; Wang, M.; Li, C. J. Angew. Chem., Int. Ed. 2002, 41, 2138; (d) Kozik1, B.;
7.31e7.33 (m, 5H), 7.38e7.39 (m, 2H), 7.41e7.43 (m, 2H), 7.50 (s,1H),
7.59 (dd, J¼7.1, 1.5 Hz, 1H), 7.80 (dd, J¼7.2, 1.5 Hz, 1H). 13C NMR
(75.5 MHz, CDCl3):
d
¼29.7 (CH3), 120.6, 124.1, 124.8, 125.9, 126.4,
ꢀ
Burgie, Z. J.; Sepiot, J. J.; Wilamowski, J.; Kuczynski, M.; Gora1, M. Environ. Bio-
126.7, 127.1, 127.3, 127.8, 128.6, 128.8, 128.9, 129.4 (CH), 131.2, 131.4,
133.3,133.5,135.6,136.2,138.2,139.0, 140.5 (C), 202.3 (CO). IR (KBr):
v¼3063 (w), 2929, 2857, 1714 (m), 1588 (w), 1498, 1362, 1353, 1244
technol. 2006, 20.
7. (a) Crawford, G. J. Am. Chem. Soc. 1939, 61, 608; (b) Bergmann, F.; Echinazi, E.;
Schapiro, D. J. Am. Chem. Soc. 1942, 64, 557.
8. For reviews of cross-coupling reactions of polyhalogenated heterocycles, see:
(m), 1218, 1192, 1087 (s), 1013, 907 (m), 823, 764, 740, 690 (s) cmꢂ1
.
€
€
(a) Schroter, S.; Stock, C.; Bach, T. Tetrahedron 2005, 61, 2245; (b) Schnurch, M.;
Flasik, R.; Khan, A. F.; Spina, M.; Mihovilovic, M. D.; Stanetty, P. Eur. J. Org. Chem.
2006, 3283.
GCeMS (EI, 70 eV): m/z (%)¼390 (Mþ, 99), 347 (23), 279 (61). HRMS
(EI, 70 eV): calcd for C26H16Cl2O [M]þ: 390.0651; found: 390.0648.
Anal. Calcd for C, 73.67; H, 4.12; found: C, 73.64; H, 4.09.
9. For palladium-catalyzed reactions from our group, see for example: (a) Dang, T.
T.; Dang, T. T.; Ahmad, R.; Reinke, H.; Langer, P. Tetrahedron Lett. 2008, 49, 1698;
(b) Dang, T. T.; Villinger, A.; Langer, P. Adv. Synth. Catal. 2008, 350, 2109; (c)
Hussain, M.; Nguyen, T. H.; Langer, P. Tetrahedron Lett. 2009, 50, 3929; (d) Dang,
T. T.; Dang, T. T.; Rasool, N.; Villinger, A.; Langer, P. Adv. Synth. Catal. 2009, 351,
1595.
Acknowledgements
Financial support by the State of Mecklenburg-Vorpommern is
gratefully acknowledged.
10. (a) Kamikawa, T.; Hayashi, T. Tetrahedron Lett. 1997, 38, 7087; (b) Littke, A. F.;
Dai, C. Y.; Fu, G. C. J. Am. Chem. Soc. 2000, 122, 4020; (c) Roy, A. H.; Hartwig, J. F.
Organometallics 2004, 23, 194; (d) Espinet, P.; Echavarren, A. M. Angew. Chem.,
Int. Ed. 2004, 43, 4704; (e) Espino, G.; Kurbangalieva, A.; Brown, J. M. Chem.
Commun. 2007, 1742 and references cited therein.
References and notes
11. Hassan, Z.; Hussain, M.; Langer, P. Synlett 2011, 1827.
12. Bekaert, A.; Provot, O.; Rasolojaona, O.; Alami, M.; Brion, J.-D. Tetrahedron Lett.
2005, 46, 4187.
1. de Koning, C. B.; Michael, J. P.; van Ottelo, W. A. L. Tetrahedron Lett. 1999, 40,
3037.
13. (a) Bolton, R. In Bromine Compounds: Chemistry and Applications; Price, D., Id-
don, B., Wakefield, B. J., Eds.; Elsevier: Amsterdam, 1988; p 151; (b) de Kimpe,
ꢀ
a-Haloketones, a-Haloaldehydes and a-Hal-
2. Manfredi, K. P.; Blunt, J. W.; Cardellina, J. H., II; Macmahon, J. B.; Pannell, L. K.;
Cragg, G. M.; Boyd, M. R. J. Med. Chem. 1991, 34, 3402.
N.; Verhe, R. In The Chemistry of
3. (a) Bringmann, G.; Gotz, R.; Keller, P. A.; Walter, R.; Boyd, M. R.; Lang, F.; Garcia,
A.; Walsh, J. J.; Tellitu, I.; Bhaskar, K. V.; Kelly, T. R. J. Org. Chem. 1998, 63, 1090;
(b) Bringmann, G.; Gotz, R.; Harmsen, S.; Holenz, J.; Walter, R. Liebigs Ann. Chem.
1996, 2045; (c) Hobbs, P. D.; Upender, V.; Dawson, M. I. Synlett 1997, 965; (d)
Hobbs, P. D.; Upender, V.; Liu, J.; Pollart, D. J.; Thomas, D. W.; Dawson, M. I.
Chem. Commun. 1996, 923; (e) Bringmann, G.; Harmsen, S.; Holenz, J.; Geuder,
T.; Gotz, R.; Keller, P. A.; Walter, R.; Ha]lock, Y. F.; Cardellina, J. H., II; Boyd, M. R.
Tetrahedron 1994, 50, 9643; (f) Kelly, T. R.; Garcia, A.; Lang, F.; Walsh, J. J.;
Bhaskar, K. V.; Boyd, M. R.; Gotz, R.; Keller, P. A.; Walter, R.; Bringmann, G.
Tetrahedron Lett. 1994, 35, 7621; (g) Hoye, T. R.; Chen, M.; Mi, L.; Priest, O. P.
Tetrahedron Lett. 1994, 47, 8747.
oimines; Patai, S., Rappoport, Z., Eds.; Wiley: 1988.
14. (a) Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95, 2457; (b) Miyaura, N. Top.
Curr. Chem. 2002, 219, 11; (c) Suzuki, A.; Yamamoto, Y. Chem. Lett. 2011,
40, 894.
15. CCDC 871741e871745 contain all crystallographic details of this publication and
is available free of charge at www.ccdc.cam.ac.uk/conts/retrieving.html or can
be ordered from the following address: Cambridge Crystallographic Data
Centre, 12 Union Road, GB-Cambridge CB21EZ; Fax: (þ44)1223-336-033; or
deposit@ccdc.cam.ac.uk.
ꢀ
16. Pena, P.; Perez, D.; Guitian, E.; Castedo, L. J. Org. Chem. 2000, 65, 6944.
17. Abid, O.-u.-R.; Ibad, M. F.; Nawaz, M.; Sher, M.; Rama, N. H.; Villinger, A.; Langer,
4. Aggarwal, B. B.; Bhardwaj, A.; Aggarwal, R. S.; Seeram, N. P.; Shishodia, S.; Ta-
kada, Y. Anticancer Res. 2004, 24, 2783.
P. Tetrahedron Lett. 2010, 51, 1541.