Suzuki Coupling of Chiral 1,1′-Binaphthyl Systems - New Synthetic Routes to Functionalize the 2- and 2,2′-Positions

Article abstract of DOI:10.1002/(SICI)1099-0690(199804)1998:4<701::AID-EJOC701>3.0.CO;2-E

1,1′-Binaphthyl derivatives 1-5, substituted in the 2- or 2,2′-positions are used in palladium-catalyzed Suzuki coupling reactions. The mono- and bis-borylated coupling components 2, 4 and 5 can easily be prepared and purified, are air-stable and are therefore interesting starting materials for Suzuki coupling reactions with several aryl halides. Thus a variety of new axially-chiral 2- and 2,2′-arylated 1,1′-binaphthyls can be synthesized. Selective monoarylation of 3, 4 and 5 can be performed. Subsequent and stepwise arylation offers general access to unsymmetrically substituted binaphthyls. Moreover, interesting atropisomeric complex molecules, such as 4,4′-bis[2-(1,1′-binaphthyl)]-1,1′-biphenyl (18a), are accessible. Compounds of type 18, which can be obtained by twofold Pd-catalyzed coupling reactions, are of high potential value as ligands or promoters in catalytic, asymmetric processes or as chiral precursor molecules for host-guest interactions.

Full text of DOI:10.1002/(SICI)1099-0690(199804)1998:4<701::AID-EJOC701>3.0.CO;2-E

FULL PAPER
Palladium-Catalyzed Reactions, 2[᭛]
Suzuki Coupling of Chiral 1,1Ј-Binaphthyl Systems ؊ New Synthetic Routes
to Functionalize the 2- and 2,2Ј-Positions
Birgit Schilling and Dieter E. Kaufmann*
Institut für Organische Chemie der Technischen Universität Clausthal,
Leibnizstraße 6, D-38678 Clausthal-Zellerfeld, Germany
Fax: (internat.) ϩ49(0)5323/72-2834
E-mail: dieter.kaufmann@tu-clausthal.de
Received September 22, 1997
Keywords: Palladium / Chirality / Boron / CϪC Coupling
1,1Ј-Binaphthyl derivatives 1-5, substituted in the 2- or 2,2Ј-
positions are used in palladium-catalyzed Suzuki coupling
fers general access to unsymmetrically substituted binaph-
thyls. Moreover, interesting atropisomeric complex molecu-
reactions. The mono- and bis-borylated coupling compo- les, such as 4,4Ј-bis[2-(1,1Ј-binaphthyl)]-1,1Ј-biphenyl (18a),
nents 2, 4 and 5 can easily be prepared and purified, are
are accessible. Compounds of type 18, which can be obtained
air-stable and are therefore interesting starting materials for
by twofold Pd-catalyzed coupling reactions, are of high po-
Suzuki coupling reactions with several aryl halides. Thus a tential value as ligands or promoters in catalytic, asymmetric
variety of new axially-chiral 2- and 2,2Ј-arylated 1,1Ј-binaph-
thyls can be synthesized. Selective monoarylation of 3, 4 and
5 can be performed. Subsequent and stepwise arylation of-
processes or as chiral precursor molecules for host-guest
interactions.
Axially-chiral compounds are of great synthetic value in Scheme 1. Potential starting materials for Suzuki coupling reac-
tions
organic chemistry. The binaphthyl-based atropisomers, es-
pecially, have proved to be extremely important as chiral
inductors for asymmetric synthesis, with a high degree of
enantioselectivity in various stoichiometric and catalytic
asymmetric transformations[2]. Our investigations of the
syntheses and applications of chiral organoboranes[3] have
led to the development of bidentate Lewis acids offering
the possibility of cooperative binding effects in asymmetric
catalysis. We have thus recently reported on the first syn-
thesis of 2- and 2,2Ј-boryl-substituted 1,1Ј-binaphthyls[4]
.
Meanwhile, the synthesis of 2 could be optimized by boryl-
ation of 1 and subsequent esterification with pinacol to
yield 58% of the pinacol ester 2.
These new axially-chiral mono- and bis-borylated 1,1Ј-
binaphthyls offer new synthetic routes towards func-
tionalized binaphthyl systems and are interesting starting
materials for Pd-catalyzed CϪC coupling reactions such as
the Suzuki coupling. Cross-coupling reactions of aryl boron
derivatives with aryl halides to synthesize biaryls have been
extensively studied[5]
.
This type of Suzuki coupling reaction can be used for the
synthesis of natural products, containing polyfused aro-
matic rings, such as azafluoranthene alkaloids[6] or (Ϫ)-ste-
ganone[7] (antileukaemic bisbenzocyclooctadiene lignan
lactone).
which play an important role in a number of diverse tech-
nologies, including high-performance engineering materials,
conducting polymers and nonlinear optical materials.
Moreover, by repetitive Suzuki coupling, interesting nano-
structures can be achieved[9]
.
In recent years, Suzuki couplings have been used to ob-
tain aromatic rigid-rod polymers, such as polyphenylenes[8]
,
Diederich et al.[10] described the synthesis of potential
chiral receptors based on binaphthyl units, which can be
obtained by Stille coupling. But there are only a few ex-
[᭛]
Part 1: See ref.[1]
.
Eur. J. Org. Chem. 1998, 701Ϫ709
WILEY-VCH Verlag GmbH, D-69451 Weinheim, 1998
1434Ϫ193X/98/0404Ϫ0701 $ 17.50ϩ.50/0
701

B. Schilling, D. E. Kaufmann
FULL PAPER
amples of Suzuki coupling of binaphthyls, such as the bisar- means of silicon-boron exchange) to offer new possibilities
ylation in the 3,3Ј-positions[11]. Pu et al. investigated Suzuki for subsequent Suzuki coupling reactions.
coupling reactions in the 6,6Ј-binaphthyl positions to syn-
Further investigations were carried out with 2,2Ј-disub-
stituted 1,1Ј-binaphthyls 3Ϫ5.
thesize conjugated polymers with main-chain chirality[12]
.
This paper is the first to report on Suzuki coupling of chiral
binaphthyls in the 2- and 2,2Ј-positions, which offers easy
and general access to a number of new atropisomeric 1,1Ј-
binaphthyl derivatives.
Scheme 3. Suzuki coupling of 2,2Ј-dibromo-1,1Ј-binaphthyl (3)
Results and Discussion
As the arylboronic acid components 2, 4 and 5 are o-
substituted, the Suzuki coupling reactions were expected to
be sensitive to steric hindrance[13][5b]. We decided to use
nonaqueous reaction conditions[14]. The couplings were
performed either in a mixture of toluene and ethanol or in
DMF, using freshly synthesized tetrakis(triphenylphos-
phane)palladium(0) as catalyst. Solid sodium carbonate was
used as base, and the reaction was heated at 100°C for
12Ϫ24 h. Investigating the following reactions all axially-
chiral substances shown were used as racemates.
Scheme 2. Synthesis of monoarylated binaphthyl systems
As shown in Scheme 3, 2,2Ј-dibromo-1,1Ј-binaphthyl (3)
could be selectively monoarylated by means of coupling re-
actions with phenyl boronic acids and esters 6a, 6b and 6d
or with 1-naphthyl boronic acid (6e). The resulting 2-
bromo-2Ј-aryl-1,1Ј-binaphthyls 10 (assignment of the struc-
ture on the basis of MS data) were reduced to yield the 2-
aryl-1,1Ј-binaphthyls 7 as main products (34Ϫ67%, Table
1). The bisarylated species could only be detected in trace
amounts (< 3%) by mass spectrometry. As before, 2Ϫ9%
of the homocoupled products 8 of the boronic acid compo-
nents were obtained. Therefore, the Suzuki coupling reac-
tion allows the synthesis of a variety of new chiral monoar-
ylated binaphthyl compounds 7aϪ7f (see Schemes 2Ϫ4).
Suzuki coupling of 1,1Ј-binaphthyl-2,2Ј-diboronic acid
(5b) with several aryl halides 9b, 12a, 12d and 12f in DMF
led to the formation of 2-monoarylated 1,1Ј-binaphthyls 7
in modest yields (23Ϫ34%, see Scheme 4, Table 2). The by-
product 7a (10Ϫ30%) could be separated (except for entry
2) and results from the partial incorporation of phenyl
groups from the triphenylphosphane ligands of the cata-
lyst[16]. For entry 4, 11% of the homocoupled product of 4-
nitroiodobenzene (12f) (4,4Ј-dinitro-1,1Ј-biphenyl) could be
isolated. This coupling type has already been reported by
Dziuba et al.[17]. When purifying the crude reaction mixture
2-Bromo-1,1Ј-binaphthyl (1) was reacted with the bor- by flash chromatography, the primary products 2-aryl-1,1Ј-
onic acids 6a and 6b, to give 2-monoarylated binaphthyls binaphthyl-2Ј-boronic acids were probably cleaved by the
7a and 7b in good to excellent yields (81Ϫ95%, see Scheme silica gel to the corresponding 2-aryl-1,1Ј-binaphthyls 7. To
2). Some homocoupling[15] of the boronic acid components confirm this, the crude product mixture of a coupling reac-
was observed (11% of biphenyl 8a and < 3% of 4,4Ј-di- tion of the diboronic acid 5b with 9a was reacted with pina-
methylbiphenyl 8b). When 1,1Ј-binaphthyl-2-boronic acid col. In this case, 30% of the stable 2-phenyl-1,1Ј-binaphthyl-
pinacol ester (2) was treated with the aryl halides 9a and 2Ј-boronic acid pinacol ester (13) could be isolated. Better
9c, no homocoupling of the boronic acid component was yields were obtained when the diboronic acid bispinacol es-
detected. The products 7a and 7c were isolated in good ter 5a was coupled directly with 9a to give 41% of 13. In
yields (63Ϫ84%). 2-(4-Trimethylsilylphenyl)-1,1Ј-binaphthyl the synthesis of 13, the by-product 2-phenyl-1,1Ј-binaphthyl
(7c) is a very interesting coupling product, since the tri- (7a, by deborylation of 13) and the autoxidation product 2-
methylsilyl group can easily be further substituted (for ex- hydroxy-2Ј-phenyl-1,1Ј-binaphthyl (14) were observed. The
ample, by halides or by boronic acid functionalities by autoxidation of organoboron compounds is described in
702
Eur. J. Org. Chem. 1998, 701Ϫ709

Palladium-Catalyzed Reactions, 2
FULL PAPER
Table 1. Suzuki coupling of 2,2Ј-dibromo-1,1Ј-binaphthyl (3)
Yields of the products
Entry
ArB(OR)2
1
2
3
4
6a HϪC6H4ϪB(OH)2
67% of 7a
50% of 7b
34% of 7d
62% of 7e
<3% of 10a[a]
<3% of 11a[a]
2% of 8a[a]
3% of 8b[a]
9% of 8d
8% of 8e
6b p-CH3ϪC6H4ϪB(OH)2
6d p-CH3OϪC6H4ϪB(O2C6H12)
6e 1-C10H7ϪB(OH)2
16% of 10b[a]
14% of 10d[a]
ഠ4% of 10e[a]
<3% of 11b[a]
<3% of 11d[a]
<3% of 11e[a]
[a]
Detection and assignment by mass spectrometry.
Scheme 4. Suzuki coupling of borylated binaphthyl systems
2-Bromo-1,1Ј-binaphthyl-2Ј-boronic acid pinacol ester
(4) is a valuable starting material for Suzuki coupling reac-
tions. Compound 4 was coupled with 9a to obtain 34% of
7a (see Scheme 4). As shown before (see Scheme 3), the
bromo-functionality of the primary coupling product was
reduced.
A great challenge in our work was the twofold palladium-
catalyzed Suzuki reactions using the starting materials
shown in Scheme 1. To optimize the reaction conditions,
coupling reactions with the naphthyl system were per-
formed first (see Scheme 5).
Scheme 5. Twofold Pd-catalyzed Suzuki coupling
Table 2. Suzuki coupling of bisborylated binaphthyl (5b)
Entry
no.
R
X
Products
By-product
1
2
3
4
12a
9b
12d
12f
H
I
34% of 7a
24% of 7b
23% of 7d
26% of 7f
Ϫ
Me
Br
I
10% of 7a
30% of 7a
22% of 7a
OMe
NO2
I
[a]
Products 7a and 7b could not be separated.
the literature, even under anhydrous conditions[18]. Route I
for the synthesis of 13 yielded 9% of 7a and 8% of 14,
whereas route II yielded 2% of 7a and 23% of 14. Monoar-
ylated, monoboronic acid pinacol esters of type 13 can be
obtained in fair yields. A subsequent Suzuki reaction
should open up new routes to chiral 2,2Ј-bisarylated bi-
naphthyl systems.
1,4-Bis(1-naphthyl)benzene (16b) could easily be ob-
tained (48%) by coupling of 6f with 1,4-dibromobenzene
Eur. J. Org. Chem. 1998, 701Ϫ709
703

B. Schilling, D. E. Kaufmann
FULL PAPER
[9d, by-product: 33% of 1-phenylnaphthalene (16a), type 13 or 18 are of high potential value for chiral recog-
monoarylation product with subsequent reduction of the nition reactions (especially as enantioselective bioorganic
bromo-functionality]. Similarly, 4,4Ј-bis(1-naphthyl)-1,1Ј- sensor molecules to differentiate carbohydrates and other
biphenyl (16d) can be synthesized in one step (30%) by biomolecules[21]) or as ligands or promoters in catalytic,
coupling of 6e with 4,4Ј-dibromo-1,1Ј-biphenyl (15a) or by asymmetric processes.
isolating 20% of the monoarylated 1-[4-(4Ј-bromo-1,1Ј-bi-
We gratefully acknowledge the support of this work by the Fonds
phenyl)]naphthalene (16c, no reduction of the bromo-func-
der Chemischen Industrie, Degussa AG, Frankfurt a. M. and the
tionality) and subsequent coupling with a second equivalent
Chemetall GmbH, Langelsheim. We are indebted to Dr. G. Remberg
(Universität Göttingen) for high-resolution MS measurements.
of 6f to obtain 16d quantitatively.
Therefore, the Suzuki coupling offers access to polyfused
aromatics, such as 16b (Hart synthesized 16b by a Grignard
reaction in 21% yield[19]; Suzuki reaction shown in this
paper: 48% yield) and 16d which are interesting substances
Experimental Section
All experiments were carried out under dry purified nitrogen or
under argon in flame-dried reaction flasks. All solvents were dried
by standard methods. Ϫ IR: Bruker Vector 22 FT-IR. Ϫ NMR:
because of their fluorescence properties[20]
Scheme 6. Synthesis of complex molecules
.
Bruker AMX 400 or AC 250 P (400 MHz or 200 MHz and 100
1 H,
MHz or 50 MHz, for
13C and 11B, respectively) with TMS
(internal) and 11BF3иOEt2 (external) as reference. Ϫ MS (70 eV, EI;
CI): Hewlett-Packard 5989B; MS (high-resolution): Finnigan MAT
95; Institut für Organische Chemie (Göttingen). Ϫ Melting points
(uncorrected): Büchi apparatus. Ϫ Elemental analyses: Institut für
Pharmazeutische Chemie (Braunschweig). Ϫ Chromatography:
Flash silica gel 60 (230Ϫ400 mesh, ASTM, Merck). Ϫ Starting
material: 2-bromo-1,1Ј-binaphthyl[22] (1) and 2,2Ј-dibromo-1,1Ј-bi-
naphthyl[23] (3) were prepared according to published procedures,
1,1Ј-binaphthyl-2-boronic acid pinacol ester (2), 2-bromo-1,1Ј-bi-
naphthyl-2Ј-boronic acid pinacol ester (4), 1,1Ј-binaphthyl-2,2Ј-di-
boronic acid bispinacol ester (5a) and 1,1Ј-binaphthyl-2,2Ј-dibo-
ronic acid (5b) were prepared as described in the preceeding
paper[4]. An optimized synthetic route to the mono boronic acid
pinacol ester (2) is presented in this paper. All axially-chiral sub-
stances were used as racemates.
2-Bromo-1,1Ј-binaphthyl (1): To a solution of 2,2Ј-dibromo-1,1Ј-
binaphthyl (3, 2.000 g, 4.85 mmol) in 30 ml of THF a 1.6  solution
of n-butyllithium (3.03 ml, 4.85 mmol) was added at Ϫ40°C. After
1 h of stirring the mixture was cooled to Ϫ78°C and 5 equiv. of 1 
hydrochloric acid (0.45 ml, 25.00 mmol) were added. The reaction
mixture was allowed to warm to room temperature overnight. The
solvents were evaporated under reduced pressure. The solid residue
was dissolved in 50 ml of diethyl ether and was then hydrolyzed
with 1  hydrochloric acid. The product was extracted with 500 ml
of diethyl ether, which was washed successively with a saturated
aqueous sodium hydrogen carbonate solution, water and a satu-
rated sodium chloride solution. The crude product was dried with
sodium sulfate. The solvents were evaporated under reduced pres-
sure and purified by flash column chromatography (hexane). The
product 1 (1.422 g, 72%) was isolated as a yellow solid, m.p.
107Ϫ108°C. Ϫ IR (KBr, cmϪ1): ν˜ ϭ 3055 (w, ArH), 1581 (m), 1503
(s), 1373 (m), 1114 (m), 803 (s), 778 (s). Ϫ 1H NMR (200 MHz,
CDCl3): δ ϭ 7.15Ϫ7.35 (m, 4 H, arom. CH), 7.37Ϫ7.54 (m, 3 H,
As shown in Scheme 6, the hitherto unknown complex
molecule 4,4Ј-bis[2-(1,1Ј-binaphthyl)]-1,1Ј-biphenyl (18a)
could be obtained in 32% yield by the coupling of mono-
borylated 2 with 15a {by-product: 12% of 2-[4-(1,1Ј-biphen-
yl)]-1,1Ј-binaphthyl (17), monoarylation product with sub-
sequent reduction of the bromo-functionality}. 18a could
either be obtained as racemate or as the corresponding
meso compound. In the NMR spectra no diastereoisomeric
signals could be observed. The reaction of 2,2Ј-dibromo- arom. CH), 7.62 (dd, J ϭ 8.4, J ϭ 7.2 Hz, 1 H, arom. CH), 7.78
(d, J ϭ 8.4 Hz, 1 H, arom. CH), 7.83 (d, J ϭ 8.4 Hz, 1 H, arom.
CH), 7.90 (d, J ϭ 8.4 Hz, 1 H, arom. CH), 7.96 (d, J ϭ 8.4 Hz, 1
H, arom. CH), 7.97 (d, J ϭ 8.4 Hz, 1 H, arom. CH). Ϫ 13C NMR
(50 MHz, CDCl3): δ ϭ 122.67 (arom. quat. CϪBr, 1 C), 125.48,
125.71, 126.00, 126.09, 126.34, 126.76, 126.92, 127.91 and 127.94
(arom. CH, 9 C), 128.33 (arom. CH, 2 C), 129.27 and 129.94
(arom. CH, 2 C), 131.98, 132.27, 133.61, 134.36, 137.28 and 138.04
(arom. quat. C, 6 C). Ϫ MS (70 eV, EI); m/z (%): 335 (6) and 333
(6, Mϩ ϩ 1), 334 (24) and 332 (23, Mϩ), 253 (100), 252 (66), 127
(31), 126 (56), 125 (34). Ϫ C20H13Br (333.2): calcd. C 72.09, H 3.93,
1,1Ј-binaphthyl (3) with 1,1Ј-biphenyl-4,4Ј-diboronic acid
bispinacol ester (15b), which can be synthesized in 67%
yield from 4,4Ј-dibromo-1,1Ј-biphenyl (15a), also gave 18a
(41%). No bromo-substituted monoarylation product could
be detected, as it was obviously immediately reduced to 18a.
Future target molecules are the dibrominated and the
bisborylated substances 18b and 18c, respectively (see
Scheme 6). These compounds could be accessible by Suzuki
reaction of 3, 4 and 5 with the appropriate halide and bo-
ronic acid components. Atropisomeric target molecules of Br 23.98; found C 72.31, H 4.00, Br 23.64.
704 Eur. J. Org. Chem. 1998, 701Ϫ709

Palladium-Catalyzed Reactions, 2
FULL PAPER
Monoborylation of 2-Bromo-1,1Ј-binaphthyl (1) and Subsequent
Esterification with Pinacol Giving 1,1Ј-Binaphthyl-2-boronic Acid
Compound 1 (150 mg, 0.450 mmol) in 20 ml of toluene, 1 equiv.
of 6b (61 mg, 0.450 mmol) in 20 ml of ethanol and Pd(PPh3)4 (52
Pinacol Ester (2): To a solution of 2-bromo-1,1Ј-binaphthyl (1, 161 mg, 0.045 mmol, 10 mol%) were allowed to react for 24 h. The
mg, 0.48 mmol) in 20 ml of THF a 1.7  solution of n-butyllithium crude product was purified by flash column chromatography (hex-
(0.28 ml, 0.48 mmol) was added at Ϫ40°C. After stirring for 1 h, ane). The by-products (< 3%), 4,4Ј-dimethyl-1,1Ј-biphenyl (8b) and
the mixture was cooled to Ϫ78°C and added to a solution of 2.5 1,1Ј-binaphthyl (8e) were characterized on the basis of GC-MS
equiv. of trimethyl borate (0.13 ml, 1.210 mmol) in 20 ml of THF. data. The main product 7b was isolated as a white solid (147 mg,
The reaction mixture was allowed to warm to room temperature 95%), m.p. 123°C. Ϫ IR (KBr, cmϪ1): ν˜ ϭ 3045 (m, ArH), 2964
overnight. The solvents were evaporated under reduced pressure. (w), 1590 (w), 1364 (w), 1260 (m), 1022 m, 801 (s), 780 (s), 771 (s),
1
The solid residue was dissolved in 50 ml of diethyl ether and was
then hydrolyzed with 1  hydrochloric acid. The product was ex-
750 (s). Ϫ H NMR (200 MHz, CDCl3): δ ϭ 2.09 (s, 3 H, CH3),
6.77 (d, J ϭ 8.4 Hz, 2 H, arom. CH), 6.90 (d, J ϭ 8.4 Hz, 2 H,
tracted with 250 ml of diethyl ether, which was washed with a satu- arom. CH), 7.12Ϫ7.42 (m, 8 H, arom. CH), 7.57 (d, J ϭ 8.4 Hz, 1
rated aqueous sodium hydrogen carbonate solution and water. The H, arom. CH), 7.74 (d, J ϭ 8.4 Hz, 1 H, arom. CH), 7.79 (d, J ϭ
crude product was dried with sodium sulfate. The solvents were
evaporated under reduced pressure and the solid residue was dis-
solved in 10 ml of toluene. Pinacol (118 mg, 1.210 mmol, 2.5 equiv.)
was added and the solution was heated under reflux for 12 h. The
8.4 Hz, 1 H, arom. CH), 7.86 (d, J ϭ 8.4 Hz, 1 H, arom. CH), 7.92
(d, J ϭ 8.4 Hz, 1 H, arom. CH). Ϫ 13C NMR (50 MHz, CDCl3):
δ ϭ 20.97 (CH3, 1 C), 125.29, 125.52, 125.55, 125.96, 126.19,
126.62, 127.09, 127.41, 127.80, 127.89 and 128.16 (arom. CH, 11
solvents were evaporated under reduced pressure. The crude prod- C), 128.22 (arom. CH, 2 C), 128.52 (arom. CH, 1 C), 129.03 (arom.
uct was purified by flash column chromatography (hexane/ethyl CH, 2 C), 129.07 (arom. CH, 1 C), 132.49, 133.19, 133.31, 133.58,
acetate, 25:1). The product 2 (107 mg, 58%) was isolated as a white 135.51, 135.82, 137.09, 138.95 and 139.36 (arom. quat. C, 9 C). Ϫ
solid and was identified by comparison to authentic material[4]
.
MS (70 eV, EI); m/z (%): 345 (28, Mϩ ϩ 1), 344 (100, Mϩ), 343
(24), 329 (26), 313 (14), 300 (5), 289 (3), 276 (3), 253 (11), 252 (14),
163 (15), 157 (15), 77 (1), 65 (1). Ϫ C27H20 (344.5): calcd. C 94.15,
H 5.85; found C 93.99, H 5.92; HR MS: calcd. 344.1565; found
344.1565.
Suzuki Coupling; General Procedure: To a solution of the aryl-
boronic acid or the arylboronic acid pinacol ester in ethanol, was
added the aryl halide dissolved in toluene, and 1Ϫ10 mol% of the
catalyst tetrakis(triphenylphosphane)palladium(0). In some cases,
which are especially mentioned, DMF was used as solvent. In all
cases, sodium carbonate was used as a base and the reaction mix-
Coupling of 1,1Ј-Binaphthyl-2-boronic Acid Pinacol Ester (2) with
Bromobenzene (9a) Giving 2-Phenyl-1,1Ј-binaphthyl (7a): Com-
ture was heated at 100°C. The solution was then hydrolyzed with 1 pound 2 (50 mg, 0.132 mmol) in 20 ml of ethanol, 1 equiv. of 9a
 hydrochloric acid and extracted with diethyl ether. The combined (0.01 ml, 0.132 mmol) in 20 ml of toluene and Pd(PPh3)4 (15 mg,
organic phases were washed three times with a saturated sodium 0.013 mmol, 10 mol%) were allowed to react for 24 h. The crude
hydrogen carbonate solution, twice with water and twice with a product was purified by flash column chromatography (hexane).
saturated sodium chloride solution. They were then dried with an-
hydrous sodium sulfate and finally the solvent was removed under
reduced pressure. The crude product was purified by flash column
chromatography on silica gel.
The product 7a was isolated as a white solid (37 mg, 84%), spectro-
scopic data for 7a see above.
Coupling of 1,1Ј-Binaphthyl-2-boronic Acid Pinacol Ester (2) with
1-Bromo-4-trimethylsilylbenzene
(9c)
Giving
2-(4-Trimeth-
Coupling of 2-Bromo-1,1Ј-binaphthyl (1) with 1-Phenylboronic
ylsilylphenyl)-1,1Ј-binaphthyl (7c): Compound 2 (36 mg, 0.094
Acid (6a) Giving 2-Phenyl-1,1Ј-binaphthyl (7a): Compound 1 (134 mmol) in 20 ml of ethanol, 1 equiv. of 9c (22 mg, 0.094 mmol) in
mg, 0.403 mmol) in 20 ml of toluene, 1 equiv. of 6a (49 mg, 0.403 20 ml of toluene and Pd(PPh3)4 (11 mg, 0.009 mmol, 10 mol%)
mmol) in 20 ml of ethanol and Pd(PPh3)4 (47 mg, 0.040 mmol, 10 were allowed to react for 24 h. The crude product was purified by
mol%) were allowed to react for 24 h. The crude product was puri- flash column chromatography (hexane). The product 7c was iso-
fied by flash column chromatography (hexane). The by-products,
biphenyl (8a, 7 mg, 11%) and 1,1Ј-binaphthyl (8e, 15 mg , 14%) ν˜ ϭ 3056 (s, ArH), 2954 (s), 1593 (m), 1505 (m), 1366 (w), 1248
(s), 1115 (m), 842 (s), 812 (m), 781 (w). Ϫ 1H NMR (400 MHz,
lated as a white solid (24 mg, 63%), m.p. 66°C. Ϫ IR (KBr, cmϪ1):
could be isolated and identified. The main product 7a was isolated
as a white solid (107 mg, 81%), m.p. 133°C. Ϫ IR (KBr, cmϪ1): CDCl3): δ ϭ 0.14 [s, 9 H, Si(CH3)3], 7.07 (d, J ϭ 8.4 Hz, 2 H,
ν˜ ϭ 3055 (m, ArH), 2953 (m), 2926 (m), 1593 (w), 1495 (m), 1445 arom. CH), 7.15Ϫ7.30 (m, 6 H, arom. CH), 7.33Ϫ7.48 (m, 4 H,
(w), 1368 (w), 1029 (w), 824 (m), 783 (m), 762 (s). Ϫ 1H NMR (200 arom. CH), 7.66 (d, J ϭ 8.4 Hz, 1 H, arom. CH), 7.81 (d, J ϭ 8.4
MHz, CDCl3): δ ϭ 6.96Ϫ7.11 (m, 5 H, arom. CH), 7.20Ϫ7.30 (m, Hz, 1 H, arom. CH), 7.88 (d, J ϭ 8.4 Hz, 1 H, arom. CH), 7.94
4 H, arom. CH), 7.33Ϫ7.50 (m, 4 H, arom. CH), 7.66 (d, J ϭ 8.4
(d, J ϭ 8.4 Hz, 1 H, arom. CH), 8.00 (d, J ϭ 8.4 Hz, 1 H, arom.
Hz, 1 H, arom. CH), 7.79 (d, J ϭ 8.4 Hz, 1 H, arom. CH), 7.85 CH). Ϫ 13C NMR (50 MHz, CDCl3): δ ϭ Ϫ1.19 [Si(CH3)3, 3 C],
(d, J ϭ 8.4 Hz, 1 H, arom. CH), 7.95 (d, J ϭ 8.4 Hz, 1 H, arom.
CH), 8.01 (d, J ϭ 8.4 Hz, 1 H, arom. CH). Ϫ 13C NMR (50 MHz,
125.38, 125.53, 125.67, 126.03, 126.24, 126.65 and 127.17 (arom.
CH, 7 C), 127.44 (arom. quat. C, 1 C), 127.49, 127.81, 127.98 and
CDCl3): δ ϭ 125.23, 125.53, 125.69 and 125.97 (arom. CH, 4 C), 128.18 (arom. CH, 4 C), 128.47 (arom. CH, 2 C), 129.09 (arom.
126.27 (arom. CH, 2 C), 126.58 and 127.14 (arom. CH, 2 C), 127.43
(arom. CH, 2 C), 127.50, 127.83, 127.95, 128.17 and 128.33 (arom.
CH, 1 C), 132.53 (arom. CH, 3 C), 133.18, 133.32, 133.71, 135.61,
136.96, 137.96, 139.27 and 142.21 (arom. quat. C, 8 C). Ϫ MS (70
CH, 5 C), 129.17 (arom. CH, 3 C), 132.59, 133.19, 133.26, 133.53, eV, EI); m/z (%): 403 (34, Mϩ ϩ 1), 402 (88, Mϩ), 388 (36), 387
135.68, 136.90, 139.46 and 141.91 (arom. quat. C, 8 C). Ϫ MS (70
(100), 339 (4), 329 (9), 326 (13), 313 (5), 253 (3), 252 (7), 194 (13),
eV, EI); m/z (%): 331 (27, Mϩ ϩ 1), 330 (100, Mϩ), 329 (40), 313 73 (21), 59 (20). Ϫ C29H26Si (402.61): HR MS: calcd. 402.1804;
(19), 300 (6), 289 (4), 276 (3), 253 (17), 252 (20), 163 (7), 157 (7),
77 (1). Ϫ C26H18 (330.4): calcd. C 94.51, H 5.49; found C 94.36,
H 5.58.
found 402.1804.
Coupling of 2,2Ј-Dibromo-1,1Ј-binaphthyl (3) with 1-Phenylbo-
ronic Acid (6a): Compound 3 (250 mg, 0.607 mmol) in 20 ml of
toluene, 2 equiv. of 6a (148 mg, 1.213 mmol) in 20 ml of ethanol
Coupling of 2-Bromo-1,1Ј-binaphthyl (1) with 4-Methylphenyl-1-
boronic Acid (6b) Giving 2-(4-Methylphenyl)-1,1Ј-binaphthyl (7b): and Pd(PPh3)4 (70 mg, 0.061 mmol, 10 mol%) were allowed to
Eur. J. Org. Chem. 1998, 701Ϫ709 705

B. Schilling, D. E. Kaufmann
FULL PAPER
react for 24 h. The crude product was purified by flash column
2-Bromo-2Ј-(4-methoxyphenyl)-1,1Ј-binaphthyl (10d): MS (70 eV,
chromatography (hexane). The by-products 10a (< 3%), 11a (< 3%) EI); m/z (%): 441 (17) and 439 (22, Mϩ ϩ 1), 440 (65) and 438 (66,
and biphenyl (8a, 2%) could be assigned on the basis of MS data.
Mϩ), 359 (100), 344 (23), 328 (35), 326 (33), 313 (59), 250 (4), 163
The by-product 1,1Ј-binaphthyl (8e, 7 mg, 4%) and the main prod- (32), 157 (44).
uct 2-phenyl-1,1Ј-binaphthyl (7a, 135 mg, 67%) were isolated as
2,2Ј-Bis(4-methoxyphenyl)-1,1Ј-binaphthyl (11d): MS (70 eV, EI);
white solids, spectroscopic data for 7a see above.
m/z (%): 467 (9, Mϩ ϩ 1), 466 (22, Mϩ), 436 (48), 435 (5), 405 (4),
404 (3), 360 (75), 359 (21), 344 (10), 328 (22), 313 (27), 289 (11),
262 (42), 252 (32), 239 (13), 183 (44), 156 (28), 108 (29), 69 (48).
2-Bromo-2Ј-phenyl-1,1Ј-binaphthyl (10a): MS (70 eV, EI); m/z
(%): 411 (10) and 409 (9, Mϩ ϩ 1), 410 (31) and 408 (32, Mϩ), 329
(100), 327 (61), 326 (66), 313 (29), 300 (12), 252 (16), 163 (26), 157
(28), 156 (24), 77 (7), 51 (9).
Coupling of 2,2Ј-Dibromo-1,1Ј-binaphthyl (3) with 1-Naphthyl-
boronic Acid (6e): Compound 3 (300 mg, 0.728 mmol) in 20 ml of
toluene, 2.2 equiv. of 6e (278 mg, 1.618 mmol) in 15 ml of ethanol
and Pd(PPh3)4 (24 mg, 0.021 mmol, 3 mol%) were allowed to react
for 24 h. The crude product was purified by flash column chroma-
tography (hexane). The by-products 10e (ഠ 4%) and 11e (< 3%)
could be assigned on the basis of MS data. The by-product 1,1Ј-
binaphthyl (8e, 14 mg, 8%) and the main product 7e (172 mg, 62%)
were isolated as white solids.
2,2Ј-Diphenyl-1,1Ј-binaphthyl (11a): MS (70 eV, EI); m/z (%): 407
(2, Mϩ ϩ 1), 406 (6, Mϩ), 330 (38), 329 (20), 313 (8), 264 (3), 252
(11), 239 (5), 163 (15), 157 (17), 129 (24), 77 (4).
Coupling of 2,2Ј-Dibromo-1,1Ј-binaphthyl (3) with 4-Methyl-
phenyl-1-boronic Acid (6b): Compound 3 (205 mg, 0.497 mmol) in
15 ml of toluene, 2.4 equiv. of 6b (150 mg, 1.105 mmol) in 15 ml
of ethanol and Pd(PPh3)4 (25 mg, 0.022 mmol, 4 mol%) were al-
lowed to react for 24 h. The crude product was purified by flash
column chromatography (hexane). The by-products 10b (ഠ 16%),
11b (< 3%) and 2,2Ј-dimethyl-1,1Ј-biphenyl (8b, 3%) could be as-
signed on the basis of MS data. The main product 2-(4-methylphe-
nyl)-1,1Ј-binaphthyl (7b) was isolated as a white solid (86 mg, 50%),
spectroscopic data for 7b see above.
2-(1-Naphthyl)-1,1Ј-binaphthyl (7e): M.p. 175°C. Ϫ IR (KBr,
cmϪ1): ν ϭ 3040 (m, ArH), 1618 (w), 1590 (w), 1502 (m), 1394 (w),
˜
1365 (w), 1255 (w), 1013 (w), 827 (m), 799 (m), 779 (s), 748 (m).
Ϫ
1H NMR (400 MHz, CDCl3): δ ϭ 6.80Ϫ7.07 (m, 3 H, arom.
CH), 7.08Ϫ7.71 (m, 13 H, arom. CH), 7.72Ϫ7.87 (m, 2 H, arom.
CH), 7.96Ϫ8.14 (m, 2 H, arom. CH). Ϫ 13C NMR (50 MHz,
CDCl3): δ ϭ 124.67, 125.17, 125.37, 125.42, 125.67, 125.83, 125.87,
126.24, 126.29, 126.39, 126.76 and 127.02 (arom. CH, 12 C), 127.20
(arom. CH, 2 C), 127.24, 127.35, 127.95, 128.05, 128.12 and 129.17
(arom. CH, 6 C), 132.40, 132.70, 132.96, 133.23, 133.39, 133.43,
136.80, 137.26, 138.08 and 139.23 (arom. quat. C, 10 C). Ϫ MS (70
eV, EI); m/z (%): 381 (32, Mϩ ϩ 1), 380 (100), 363 (14), 350 (7),
301 (5), 265 (4), 253 (16), 252 (23), 239 (2), 187 (9), 182 (10), 176
(4), 128 (4), 127 (3). Ϫ C30H20 (380.49): HR MS: calcd. 380.1565;
found 380.1565.
2-Bromo-2Ј-(4-methylphenyl)-1,1Ј-binaphthyl (10b): MS (70 eV,
EI); m/z (%): 425 (12) and 423 (13, Mϩ ϩ 1), 424 (41) and 422 (41,
Mϩ), 344 (32), 343 (100), 328 (59), 327 (55), 326 (59), 313 (15), 252
(5), 163 (42), 157 (26), 150 (13), 77 (1).
2,2Ј-Bis(4-methylphenyl)-1,1Ј-binaphthyl (11b): MS (70 eV, EI);
m/z (%): 435 (36, Mϩ ϩ 1), 434 (100, Mϩ), 420 (71), 419 (17), 404
(8), 389 (6), 344 (54), 343 (32), 328 (27), 326 (39), 313 (18), 300 (7),
252 (10), 239 (4), 200 (9), 163 (13), 91 (11).
2-Bromo-2Ј-(1-naphthyl)-1,1Ј-binaphthyl (10e): MS (70 eV, EI);
m/z (%): 461 (9) and 459 (11, Mϩ ϩ 1), 460 (27) and 458 (30, Mϩ),
380 (31), 379 (100), 377 (44), 376 (39), 374 (20), 363 (26), 350 (11),
252 (5), 189 (15), 182 (25), 175 (13), 125 (4).
Coupling of 2,2Ј-Dibromo-1,1Ј-binaphthyl (3) with 4-Methoxy-
phenyl-1-boronic Acid Pinacol Ester (6d): Compound 3 (400 mg,
0.971 mmol) in 30 ml of toluene, 2 equiv. of 6d (454 mg, 1.941
mmol) in 30 ml of ethanol and Pd(PPh3)4 (112 mg, 0.097 mmol,
10 mol%) were allowed to react for 24 h. The crude product was
purified by flash column chromatography (hexane/ethyl acetate,
10:1). The by-products 10d (14%) and 11d (< 3%) could be as-
signed on the basis of MS data. The by-product 4,4Ј-dimethoxy-
1,1Ј-biphenyl (8d, 19 mg, 9%) was obtained as a white solid. The
main product 2-(4-methoxyphenyl)-1,1Ј-binaphthyl (7d) was iso-
lated as a white solid (119 mg, 34%).
2,2Ј-Bis(1-naphthyl)-1,1Ј-binaphthyl (11e): MS (70 eV, EI); m/z
(%): 507 (43, Mϩ ϩ 1), 506 (100), 490 (4), 456 (26), 380 (34), 379
(24), 378 (14), 363 (13), 252 (20), 239 (5), 188 (10), 127 (3), 69 (4).
Coupling of 1,1Ј-Binaphthyl-2,2Ј-diboronic Acid (5b) with Iodo-
benzene (12a): Compound 5b (80 mg, 0.234 mmol, 1.1 equiv.), 2
equiv. of 12a (0.05 ml, 0.425 mmol) in 30 ml of DMF and
Pd(PPh3)4 (24 mg, 0.026 mmol, 6 mol%) were allowed to react for
24 h. The crude product was purified by flash column chromatog-
raphy (hexane). The by-product 1,1Ј-binaphthyl (8e, 12 mg, 23%)
and the main product 2-phenyl-1,1Ј-binaphthyl (7a, 24 mg, 34%)
were isolated as white solids, spectroscopic data for 7a see above.
2-(4-Methoxyphenyl)-1,1Ј-binaphthyl (7d): M.p. 148°C. Ϫ IR
(KBr, cmϪ1): ν˜ ϭ 3053 (m, ArH), 2928 (m), 2835 (w), 1608 (m),
1578 (w), 1511 (m), 1243 (s) and 1032 (s, CϪO), 818 (w), 780 (w),
752 (w). Ϫ 1H NMR (400 MHz, CDCl3): δ ϭ 3.62 (s, 3 H, OCH3),
6.54 (d, J ϭ 8.4 Hz, 2 H, arom. CH), 6.99 (d, J ϭ 8.4 Hz, 2 H,
arom. CH), 7.18Ϫ7.27 (m, 4 H, arom. CH), 7.32Ϫ7.45 (m, 4 H,
arom. CH), 7.64 (d, J ϭ 8.4 Hz, 1 H, arom. CH), 7.80 (d, J ϭ 8.4
Hz, 1 H, arom. CH), 7.85 (d, J ϭ 8.4 Hz, 1 H, arom. CH), 7.92
(d, J ϭ 8.4 Hz, 1 H, arom. CH), 7.98 (d, J ϭ 8.4 Hz, 1 H, arom.
CH). Ϫ 13C NMR (50 MHz, CDCl3): δ ϭ 54.95 (OCH3, 1 C),
112.92 (arom. CH, 2 C), 125.32, 125.50, 125.53, 125.98, 126.19,
126.54, 127.02, 127.44, 127.79, 127.90, 128.19, 128.51 and 129.08
(arom. CH, 13 C), 130. 24 (arom. CH, 2 C), 132.40, 133.22, 133.31,
133.50, 134.29, 135.43, 137.10 and 138.98 (arom. quat. C, 8 C),
157.95 (arom. quat. CϪO, 1 C). Ϫ MS (70 eV, EI); m/z (%): 361
Coupling of 1,1Ј-Binaphthyl-2,2Ј-diboronic Acid (5b) with 1-
Bromo-4-methylbenzene (9b): Compound 5b (100 mg, 0.292 mmol,
1.1 equiv.), 2 equiv. of 9b (91 mg, 0.532 mmol) in 20 ml of DMF
and Pd(PPh3)4 (19 mg, 0.016 mmol, 3 mol%) were allowed to react
for 24 h. The crude product was purified by flash column chroma-
tography (hexane). A white solid (31 mg) could be obtained con-
sisting of a 1:2.6 mixture of the by-product 2-phenyl-1,1Ј-binaph-
thyl (7a, 10%) and the main product 2-(4-methylphenyl)-1,1Ј-bi-
naphthyl (7b, 24%), spectroscopic data for 7a and 7b see above.
Coupling of 1,1Ј-Binaphthyl-2,2Ј-diboronic Acid (5b) with 1-Iodo-
(29, Mϩ ϩ 1), 360 (100, Mϩ), 345 (9), 329 (23), 327 (21), 315 (23), 4-methoxybenzene (12d): Compound 5b (80 mg, 0.234 mmol, 1.1
302 (12), 289 (6), 252 (4), 239 (12), 157 (17). Ϫ C27H20O (360.46):
equiv.), 2 equiv. of 12d (100 mg, 0.425 mmol) in 30 ml of DMF
HR MS: calcd. 360.1514; found 360.1514.
and Pd(PPh3)4 (50 mg, 0.043 mmol, 10 mol%) were allowed to
706
Eur. J. Org. Chem. 1998, 701Ϫ709

Palladium-Catalyzed Reactions, 2
FULL PAPER
react for 24 h. The crude product was purified by flash column 13C NMR (50 MHz, CDCl3): δ ϭ 24.00 and 24.55 [OC(CH3)2, 4
chromatography (hexane and hexane/ethyl acetate, 5:1). The unde- C], 83.01 [OC(CH3)2, 2 C], 125.15, 125.61, 125.77, 126.03, 126.31,
sired product 2-phenyl-1,1Ј-binaphthyl (7a, 21 mg, 30%) and the 126.48 and 126.92 (arom. CH, 7 C), 127.05 (arom. CH, 2 C),
main product 2-(4-methoxyphenyl)-1,1Ј-binaphthyl (7d, 18 mg,
127.23, 127.33, 127.41, 127.82 and 128.02 (arom. CH, 5 C), 129.28
23%) were isolated as white solids, spectroscopic data for 7a and (arom. CH, 2 C), 130.07 (arom. CH, 1 C), 132.56, 132.82, 134.11,
7d see above.
134.40, 136.32, 139.21, 142.34 and 144.13 (arom. quat. C, 8 C). Ϫ
11B NMR (400 MHz, CDCl3): δ ϭ 30.37 (s). Ϫ MS (70 eV, EI);
m/z (%): 457 (23, Mϩ ϩ 1), 456 (69, Mϩ), 356 (36), 355 (33), 341
(15), 340 (23), 337 (34), 329 (44), 328 (100), 327 (59), 313 (19), 279
(6), 263 (2), 252 (9), 84 (22), 77 (4). Ϫ C32H29BO2 (456.2): calcd.
C 84.22, H 6.40; found C 83.29, H 6.39; HR MS: calcd. 456.2261;
found 456.2260.
Coupling of 1,1Ј-Binaphthyl-2,2Ј-diboronic Acid (5b) with 1-
Bromo-4-nitrobenzene (12f) Giving 2-(4-Nitrophenyl)-1,1Ј-binaph-
thyl (7f): Compound 5b (80 mg, 0.234 mmol, 1.1 equiv), 2 equiv.
of 12f (100 mg, 0.425 mmol) in 30 ml of DMF and Pd(PPh3)4 (25
mg, 0.021 mmol, 5 mol%) were allowed to react for 24 h. The crude
product was purified by flash column chromatography (hexane and
hexane/ethyl acetate, 8:1). The by-product 2-phenyl-1,1Ј-binaphthyl
(7a, 15 mg, 22%, spectroscopic data see above) and the yellow solid
4,4Ј-dinitro-1,1Ј-biphenyl[24] (12 mg, 11%) were isolated and iden-
tified. The main product 7f was isolated as a yellow solid (21 mg ,
26%), m.p. 209°C. Ϫ IR (KBr, cmϪ1): ν˜ ϭ 3047 (w, ArH), 1598
(m), 1518 (s) and 1345 (s, NO), 1108 (w), 1015 (w), 829 (w), 801
2-Hydroxy-2Ј-phenyl-1,1Ј-binaphthyl (14): M.p. 165°C. Ϫ IR
(KBr, cmϪ1): ν˜ ϭ 3482 (s, OϪH, free), 3418 (br.s, OϪH), 3056 (w,
ArH), 1619 (m), 1597 (m), 1517 (w), 1379 (w), 1263 (m), 1205 (m),
1103 (m) and 1027 (m, CϪO), 816 (m), 761 (m), 749 (m), 698 (m).
Ϫ
1H NMR (400 MHz, CDCl3): δ ϭ 4.83 (d, J ϭ 1.2 Hz, 1 H,
OH), 7.02Ϫ7.16 (m, 7 H, arom. CH), 7.18Ϫ7.35 (m, 4 H, arom.
CH), 7.48Ϫ7.54 (m, 1 H, arom. CH), 7.71 (dd, J ϭ 8.4 and 1.2 Hz,
1 H, arom. CH), 7.77 (d, J ϭ 8.4 Hz, 2 H, arom. CH), 7.98 (d,
J ϭ 8.4 Hz, 1 H, arom. CH), 8.09 (dd, J ϭ 8.4 and 1.2 Hz, 1 H,
arom. CH). Ϫ 13C NMR (50 MHz, CDCl3): δ ϭ 117.12 (arom.
CH, 1 C), 117.66 (arom. quat. C, 1 C), 123.18, 125.00, 126.32,
126.39, 126.57, 126.95 and 127.16 (arom. CH, 7 C), 127.65 (arom.
CH, 2 C), 128.04 and 128.17 (arom. CH, 2 C), 128.58 (arom. CH,
3 C), 128.67 (arom. quat. C, 1 C), 129.43 and 129.83 (arom. CH,
2 C), 133.11, 133.20, 134.13, 140.77, 141.54 and 141.60 (arom.
quat. C, 6 C), 150.91 (arom. quat. CϪO, 1 C). Ϫ MS (70 eV, EI);
m/z (%): 347 (27, Mϩ ϩ 1), 346 (100, Mϩ), 329 (12), 315 (11), 302
(12), 269 (5), 252 (3), 239 (13), 77 (9). Ϫ C26H18O (346.4): HR-MS:
calcd. 346.1358; found 346.1358.
1
(w), 781 (w). Ϫ H NMR (400 MHz, CDCl3): δ ϭ 7.21Ϫ7.26 (m,
3 H, arom. CH), 7.27Ϫ7.35 (m, 4 H, arom. CH), 7.38Ϫ7.47 (m, 2
H, arom. CH), 7.53 (ddd, J ϭ 8.4, J ϭ 5.6 and J ϭ 0.5 Hz, 1 H,
arom. CH), 7.62 (d, J ϭ 8.4 Hz, 1 H, arom. CH), 7.82Ϫ7.90 (m, 4
H, arom. CH), 7.99 (d, J ϭ 8.4 Hz, 1 H, arom. CH), 8.07 (d, J ϭ
8.4 Hz, 1 H, arom. CH). Ϫ 13C NMR (50 MHz, CDCl3): δ ϭ
122.75 (arom. CH, 2 C), 125.23, 125.89, 126.06, 126.40, 126.49,
126.77, 127.20, 127.24, 127.94, 128.14, 128.44, 128.47 and 129.17
(arom. CH, 13 C), 129.96 (arom. CH, 2 C), 133.07 and 133.11
(arom. quat. C, 2 C), 133.22 (arom. quat. C, 2 C), 135.90, 136.32,
137.09 and 146.24 (arom. quat. C, 4 C), 148.87 (arom. quat. CϪN,
1 C). Ϫ MS (70 eV, EI); m/z (%): 376 (28, Mϩ ϩ 1), 375 (100, Mϩ),
374 (21), 360 (7), 327 (28), 326 (33), 313 (19), 300 (12), 289 (9), 276
(6), 253 (29), 252 (20), 163 (16), 156 (17), 150 (13). Ϫ C26H17 NO2
(375.43): HR MS: calcd. 375.1259; found 375.1259.
Coupling of 1,1Ј-Binaphthyl-2,2Ј-diboronic Acid Bispinacol Ester
(5a) with Bromobenzene (9a): Compound 5a (42 mg, 0.0832 mmol)
in 5 ml of ethanol, 2 equiv. of 9a (0.018 ml, 0.1664 mmol) in 5 ml
of toluene and Pd(PPh3)4 (19 mg, 0.017 mmol, 10 mol%) were al-
lowed to react for 24 h. The crude product was purified by flash
column chromatography (hexane/ethyl acetate, 20:1 and hexane/
ethyl acetate, 6:1). 25% of the starting material 5a could be reco-
vered. The by-product 2-phenyl-1,1Ј-binaphthyl (7a, 2%) could be
assigned on the basis of GC-MS data, the by-product 2-hydroxy-
2Ј-phenyl-1,1Ј-binaphthyl (14) was obtained as a white solid (7 mg,
23%). The main product 2-phenyl-1,1Ј-binaphthyl-2Ј-boronic acid
pinacol ester (13) was isolated as a white solid (16 mg, 41%), spec-
troscopic data for 13 and 14 see above.
Coupling of 1,1Ј-Binaphthyl-2,2Ј-diboronic Acid (5b) and Bromo-
benzene (9a), Subsequent Esterification with Pinacol: Compound 5b
(200 mg, 0.585 mmol) in 20 ml of ethanol, 2 equiv. of 9a (0.123 ml,
1.170 mmol) in 20 ml of toluene and Pd(PPh3)4 (68 mg, 5 mol%)
were allowed to react for 24 h. The reaction mixture was worked
up by hydrolysis with 5 ml of 1  hydrochloric acid. The combined
organic phases were washed with 10 ml of a saturated sodium hy-
drogen carbonate solution. After drying the organic layer with an-
hydrous sodium sulfate, the solvents were removed under reduced
pressure. The solid residue, containing the corresponding diboronic
acid was dissolved in 30 ml of toluene. After addition of pinacol
(173 mg, 1.462 mmol) the reaction mixture was heated under reflux
for 12 h. The solvent was then removed under reduced pressure.
The crude product was purified by flash column chromatography
(hexane/ethyl acetate, 25:1 and hexane/ethyl acetate, 6:1). The by-
product 2-phenyl-1,1Ј-binaphthyl (7a, 17 mg, 9%, spectroscopic
data see above) and the by-product 2-hydroxy-2Ј-phenyl-1,1Ј-bi-
naphthyl (14, 16 mg, 8%) were isolated as white solids. The main
product 2-phenyl-1,1Ј-binaphthyl-2Ј-boronic acid pinacol ester (13)
was obtained as a white solid (81 mg, 30%).
Coupling of 2-Bromo-1,1Ј-binaphthyl-2,2Ј-boronic Acid Pinacol
Ester (4) with Bromobenzene (9a): Compound 4 (30 mg, 0.065
mmol) in 10 ml of ethanol, 1 equiv. of 9a (0.01 ml, 0.065 mmol) in
10 ml of toluene, and Pd(PPh3)4 (8 mg, 0.007 mmol, 10 mol%)
were allowed to react for 24 h. The yields were determined by gas
chromatographic (GC-MS) analysis and by comparison to auth-
entic material, spectroscopic data of 7a see above. 62% of the start-
ing material 4 could be recovered. The by-product 1,1Ј-binaphthyl
(8e, 4%) and the main product 2-phenyl-1,1Ј-binaphthyl (7a, 34%)
were characterized.
2-Phenyl-1,1Ј-binaphthyl-2Ј-boronic Acid Pinacol Ester (13): M.p.
70Ϫ71°C. Ϫ IR (KBr, cmϪ1): ν˜ ϭ 3055 (m, ArH), 2976 (m), 2927
(m), 1595 (m), 1559 (w), 1494 (w), 1471 (s), 1377 (s) and 1303 (s,
Coupling of 1-Naphthylboronic Acid Pinacol Ester (6f) with 1,4-
Dibromobenzene (9d) Giving 1,4-Bis(1-naphthyl)benzene (16b):
BϪO), 1146 (s) and 1114 (s, CϪO), 821 (m), 762 (m), 749 (m), 700 Compound 6f (200 mg, 0.787 mmol, 2 equiv.) in 20 ml of ethanol,
(m). Ϫ 1H NMR (400 MHz, CDCl3): δ ϭ 0.76 and 0.96 [2 s, 12
9d (93 mg, 0.394 mmol) in 20 ml of toluene and Pd(PPh3)4 (46 mg,
H, OC(CH3)2], 6.95Ϫ7.00 (m, 3 H, arom. CH), 7.14Ϫ7.24 (m, 5 0.039 mmol, 5 mol%) were allowed to react for 24 h. The crude
H, arom. CH), 7.35Ϫ7.44 (m, 3 H, arom. CH), 7.60 (d, J ϭ 8.4 product was purified by flash column chromatography (hexane). 1-
Hz, 1 H, arom. CH), 7.77Ϫ7.83 (m, 3 H, arom. CH), 7.92 (d, J ϭ
Phenylnaphthalene (16a) was obtained as a by-product (27 mg,
8.4 Hz, 1 H, arom. CH), 7.99 (d, J ϭ 8.4 Hz, 1 H, arom. CH). Ϫ 33%). The main product 16b was isolated as a white solid (62 mg
Eur. J. Org. Chem. 1998, 701Ϫ709
707

B. Schilling, D. E. Kaufmann
FULL PAPER
, 48%), m.p. 201Ϫ202°C. Ϫ IR (KBr, cmϪ1): ν˜ ϭ 3028 (w, ArH), were allowed to react for 24 h. The crude product was purified
1590 (w), 1504 (w), 1393 (m), 1016 (w), 798 (s), 790 (s), 777 (s). Ϫ by flash column chromatography (hexane and hexane/ethyl acetate,
1H NMR (400 MHz, CDCl3): δ ϭ 7.48Ϫ7.61 (m, 8 H, arom. CH), 20:1). The by-product 17 (10 mg, 12%) and the main product 18a
7.64Ϫ7.65 (m, 4 H, arom. CH), 7.91 (d, J ϭ 8.0 Hz, 2 H, arom. (41 mg, 32%) were isolated as white solids.
CH), 7.95 (d, J ϭ 8.4 Hz, 2 H, arom. CH), 8.09 (d, J ϭ 8.4 Hz, 2
2-[4-(1,1Ј-Biphenyl)]-1,1Ј-binaphthyl (17): M.p. 210°C. Ϫ IR
H, arom. CH). Ϫ 13C NMR (50 MHz, CDCl3): δ ϭ 125.44, 125.82,
(KBr, cmϪ1): ν˜ ϭ 3042 and 3027 (w, ArH), 1619 (w), 1596 (w),
126.07, 126.10, 127.05, 127.73 and 128.33 (arom. CH, 14 C), 129.96
1502 (w), 1486 (m), 1365 (w), 819 (s), 802 (m), 783 (m), 766 (s),
(arom. CH, 4 C), 131.63, 133.86, 139.66 and 139.95 (arom. quat.
752 (m), 730 (m). Ϫ 1H NMR (400 MHz, CDCl3): δ ϭ 7.14 (d,
C, 8 C). Ϫ MS (70 eV, EI); m/z (%): 331 (26, Mϩ ϩ 1), 330 (100,
J ϭ 8.4 Hz, 2 H, arom. CH), 7.22Ϫ7.30 (m, 7 H, arom. CH),
Mϩ), 329 (17), 313 (10), 203 (11), 202 (25), 178 (6), 165 (10), 163
7.31Ϫ7.37 (m, 2 H, arom. CH), 7.38Ϫ7.43 (m, 3 H, arom. CH),
(17), 151 (6), 128 (12), 127 (6). Ϫ C26H18 (330.4): calcd. C 94.51,
7.44Ϫ7.49 (m, 3 H, arom. CH), 7.71 (d, J ϭ 8.4 Hz, 1 H, arom.
H 5.49; found C 94.27 H 5.31.
CH), 7.81 (d, J ϭ 8.4 Hz, 1 H, arom. CH), 7.87 (d, J ϭ 8.4 Hz, 1
Coupling of 1-Naphthylboronic Acid (6e) with 4,4Ј-Dibromo-1,1Ј-
biphenyl (15a): Compound 6e (150 mg, 0.872 mmol, 2 equiv.) in 20
ml of ethanol, 15a (136 mg, 0.436 mmol) in 40 ml of toluene and
Pd(PPh3)4 (50 mg, 0.044 mmol, 5 mol%) were allowed to react for
24 h. The crude product was purified by flash column chromatog-
raphy (hexane). The by-product 1,1Ј-binaphthyl (8e) was obtained
as a white solid (21 mg, 9%). The products 16c (32 mg, 20%) and
16d (53 mg, 30%) were isolated as white solids.
H, arom. CH), 7.96 (d, J ϭ 8.4 Hz, 1 H, arom. CH), 8.01 (d, J ϭ
8.4 Hz, 1 H, arom. CH). Ϫ 13C NMR (50 MHz, CDCl3): δ ϭ
125.36, 125.59, 125.73 and 126.06 (arom. CH, 4 C), 126.12 (arom.
CH, 2 C), 126.30 and 126.57 (arom. CH, 2 C), 126.84 (arom. CH,
2 C), 127.09, 127.16, 127.57, 127.84, 128.04, 128.24 and 128.33
(arom. CH, 7 C), 128.61 (arom. CH, 2 C), 129.16 (arom. CH, 1
C), 129.60 (arom. CH, 2 C), 132.61, 133.23, 133.32, 133.59, 135.72,
136.91, 138.80, 138.96, 140.55 and 140.93 (arom. quat. C, 10 C).
Ϫ MS (70 eV, EI); m/z (%): 407 (34, Mϩ ϩ 1), 406 (100, Mϩ), 405
(15), 389 (7), 326 (8), 313 (8), 276 (4), 253 (8), 252 (12), 239 (2),
203 (5), 129 (3), 77 (6). Ϫ C32H22 (406.5): HR MS: calcd. 406.1722;
found 406.1721.
1-[4-(4Ј-Bromo-1,1Ј-biphenyl)]naphthalene (16c): M.p. 165°C. Ϫ
IR (KBr, cmϪ1): ν ϭ 3026 (w, ArH), 1504 (w), 1483 (m), 1394 (m),
˜
1070 (m), 1001 (m), 803 (m), 783 (s), 739 (s). Ϫ 1H NMR (400
MHz, CDCl3): δ ϭ 7.42Ϫ7.63 (m, 10 H, arom. CH), 7.68 (d, J ϭ
8.4 Hz, 2 H, arom. CH), 7.88 (d, J ϭ 8.4 Hz, 1 H, arom. CH), 7.92
(d, J ϭ 8.4 Hz, 1 H, arom. CH), 7.95 (d, J ϭ 8.4 Hz, 1 H, arom.
CH). Ϫ 13C NMR (50 MHz, CDCl3): δ ϭ 121.63 (arom. quat.
CϪBr, 1 C), 125.40, 125.84, 125.90 and 126.12 (arom. CH, 4 C),
126.78 (arom. CH, 2 C), 126.92, 127.81 and 128.33 (arom. CH, 3
C), 128.69 and 130.62 (arom. CH, 4 C), 131.52 (arom. quat. C, 1
C), 131.96 (arom. CH, 2 C), 133.82, 138.85, 139.62, 139.73 and
140.18 (arom. quat. C, 5 C). Ϫ MS (70 eV, EI); m/z (%): 361 (20)
and 359 (30, Mϩ ϩ 1), 360 (100) and 358 (91, Mϩ), 278 (54), 276
(42), 203 (21), 202 (24), 126 (16), 77 (8), 51 (8). Ϫ C22H15Br (359.3):
calcd. C 73.55, H 4.21, Br 22.24; found C 73.56, H 4.19, Br 21.18.
4,4Ј-Bis[2-(1,1Ј-binaphthyl)]-1,1Ј-biphenyl (18a): M.p. 181°C. Ϫ
IR (KBr, cmϪ1): ν˜ ϭ 3050 (m, ArH), 1619 (w), 1592 (w), 1496 (m),
1
1366 (w), 813 (s), 802 (s), 781 (s), 750 (m). Ϫ H NMR (400 MHz,
CDCl3): δ ϭ 7.00Ϫ7.04 (m, 8 H, arom. CH), 7.17Ϫ7.26 (m, 8 H,
arom. CH), 7.31Ϫ7.46 (m, 8 H, arom. CH), 7.63 (d, J ϭ 8.4 Hz, 2
H, arom. CH), 7.76 (d, J ϭ 8.4 Hz, 2 H, arom. CH), 7.82 (d, J ϭ
8.4 Hz, 2 H, arom. CH), 7.93 (d, J ϭ 8.4 Hz, 2 H, arom. CH), 7.99
(d, J ϭ 8.4 Hz, 2 H, arom. CH). Ϫ 13C NMR (50 MHz, CDCl3):
δ ϭ 125.34, 125.58 and 125.69 (arom. CH, 6 C), 125.81 (arom. CH,
4 C), 126.03, 126.27, 126.52, 127.12, 127.54, 127.81, 127.98, 128.23,
128.31 and 129.07 (arom. CH, 20 C), 129.43 (arom. CH, 4 C),
132.56, 133.18, 133.29, 133.54, 135.63, 136.88, 138.11, 138.94 and
140.72 (arom. quat. C, 18 C). Ϫ MS (70 eV, EI); m/z (%): 658 [Mϩ],
644 (2), 574 (1), 513 (1), 458 (1), 402 (1), 329 (9, Mϩ/2), 328 (6),
313 (2), 253 (4), 252 (3), 239 (1). Ϫ C52H34 (658.8): HR MS: calcd.
658.2661; found 658.2661.
4,4Ј-Bis(1-naphthyl)-1,1Ј-biphenyl (16d): M.p. 170°C. Ϫ IR
(KBr, cmϪ1): ν˜ ϭ 3043 and 3026 (w, ArH), 1591 (w), 1494 (w),
1
1394 (m), 1003 (w), 823 (m), 800 (s), 774 (s), 569 (m). Ϫ H NMR
(400 MHz, CDCl3): δ ϭ 7.45Ϫ7.58 (m, 8 H, arom. CH), 7.63 (d,
J ϭ 8.4 Hz, 4 H, arom. CH), 7.82 (d, J ϭ 8.4 Hz, 4 H, arom. CH),
7.89 (d, J ϭ 8.4 Hz, 2 H, arom. CH), 7.93 (d, J ϭ 8.4 Hz, 2 H,
arom. CH), 8.02 (d, J ϭ 8.4 Hz, 2 H, arom. CH). Ϫ 13C NMR (50
MHz, CDCl3): δ ϭ 125.43, 125.82, 126.02 and 126.10 (arom. CH,
8 C), 126.97 (arom. CH, 6 C), 127.74 and 128.33 (arom. CH, 4 C),
130.59 (arom. CH, 4 C), 131.61, 133.86, 139.71, 139.84 and 139.86
Coupling of 2,2Ј-Dibromo-1,1Ј-binaphthyl (3) with 1,1Ј-Biphenyl-
4,4Ј-diboronic Acid Bispinacol Ester (15b): Compound 3 (412 mg,
1.000 mmol, 2 equiv.) in 20 ml of toluene, 15b (203 mg, 0.500
mmol) in 10 ml of ethanol and Pd(PPh3)4 (116 mg, 0.100 mmol,
10 mol%) were allowed to react for 24 h. The crude product was
purified by flash column chromatography (hexane and hexane/ethyl
acetate, 20:1). The by-product 1,1Ј-binaphthyl (8e) was obtained
as a white solid (24 mg, 9%). The main product 4,4Ј-bis[2-(1,1Ј-
binaphtyl)]-1,1Ј-biphenyl (18a, 134 mg, 41%) was isolated as a
white solid, spectroscopic data for 18a see above.
(arom. quat. C, 10 C). Ϫ MS (70 eV, EI); m/z (%): 407 (37, Mϩ
ϩ
1), 406 (100, Mϩ), 405 (6), 389 (6), 276 (4), 263 (1), 252 (1), 203
(19), 202 (21), 201 (8), 200 (8), 165 (2), 126 (1), 77 (1), 63 (1). Ϫ
C32H22 (406.5): calcd. C 94.55, H 5.45; found C 93.49, H 5.40: HR
MS: calcd: 406.1722; found 406.1721.
Coupling of 1-[4-(4Ј-Bromo-1,1Ј-biphenyl)]naphthalene (16c)
with 1-Naphthylboronic Acid Pinacol Ester (6f): Compound 16c (10
mg, 0.028 mmol) in 4 ml of toluene, 1 equiv. of 6f (7 mg, 0.028
mmol) in 4 ml of ethanol and Pd(PPh3)4 (3 mg, 0.0028 mmol, 10
mol%) were allowed to react for 24 h. The reaction was monitored
by gas chromatography. The starting material was quantitatively
transformed into the product 4,4Ј-bis(1-naphthyl)-1,1Ј-biphenyl
(16d), spectroscopic data for 16d see above.
1,1Ј-Biphenyl-4,4Ј-diboronic Acid Bispinacol Ester (15b): To a
solution of 4,4Ј-dibromo-1,1Ј-biphenyl (15a, 3.000 g, 9.62 mmol)
in 30 ml THF, was added a 1.6  solution of n-butyllithium (13.22
ml, 21.15 mmol) at Ϫ40°C. After stirring for 1 h, the mixture was
cooled to Ϫ78°C and added to a solution of 5 equiv. of trimethyl
borate (5.36 ml, 48.07 mmol) in 80 ml of THF. The reaction mix-
ture was allowed to warm to room temperature overnight. The sol-
vents were evaporated under reduced pressure. The solid residue
Coupling of 1,1Ј-Binaphthyl-2-boronic Acid Pinacol Ester (2) with was dissolved in 50 ml of diethyl ether and was then hydrolyzed
4,4Ј-Dibromo-1,1Ј-biphenyl (15a): Compound 2 (148 mg, 0.388
mmol, 2 equiv) in 20 ml of ethanol, 15a (61 mg, 0.194 mmol) in
20 ml of toluene and Pd(PPh3)4 (45 mg, 0.049 mmol, 10 mol%)
with 1  hydrochloric acid. The product was extracted with 250 ml
of diethyl ether, which was washed with a saturated aqueous so-
dium hydrogen carbonate solution and water. The crude product
708
Eur. J. Org. Chem. 1998, 701Ϫ709

Palladium-Catalyzed Reactions, 2
FULL PAPER
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P. Liess, V. Hensel, A.-D. Schlüter, Liebigs Ann. 1996,
was dried with sodium sulfate. The solvents were evaporated under
reduced pressure and the solid residue was dissolved in 50 ml of
toluene. Pinacol (5.681 g, 48.07 mmol, 5 equiv.) was added and
the solution was heated under reflux for 12 h. The solvents were
evaporated under reduced pressure. The crude product was purified
by flash column chromatography (hexane/ethyl acetate, 25:1). The
product 15b (1.499 g, 67%) was isolated as a white solid, m.p.
221°C. Ϫ IR (KBr, cmϪ1): ν˜ ϭ 3029 (w, ArH), 2982 (s), 1607 (m),
1502 (w), 1393 and 1357 (s, BϪO), 1145 and 1093 (s, CϪO), 860
1037Ϫ1040. Ϫ[9b] A.-D. Schlüter, G. Wegner, Acta Polym. 1993,
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2253Ϫ2256.
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Q.-S. Hu, D. Vitharana, G.-Y. Liu, V. Jain, M. W. Waga-
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1082Ϫ1084. Ϫ [12b] Q.ϪS. Hu, D. Vitharana, G. Liu, V. Jain, L.
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Pu, Macromolecules 1996, 29, 5075Ϫ5082. Ϫ
L. Ma, Q.-S.
1
(m), 820 (m), 657 (m). Ϫ H NMR (400 MHz, CDCl3): δ ϭ 1.36
Hu, K. Y. Musick, D. Vitharana, C. Wu, C. M. S. Kwan, L.
[12d]
(s, 24 H, OCCH3), 7.63 (d, J ϭ 8.4 Hz, 4 H, arom. CH), 7.88 (d,
J ϭ 8.4 Hz, 4 H, arom. CH). Ϫ 13C NMR (50 MHz, CDCl3): δ ϭ
24.85 (OCCH3, 8 C), 83.82 (OCCH3, 4 C), 126.49 and 135.23
(arom. CH, 8 C), 143.61 (arom. quat. C, 2 C). Ϫ MS (70 eV, EI);
m/z (%): 407 (26, Mϩ ϩ 1), 406 (100, Mϩ), 405 (49), 391 (19), 320
(63), 307 (41), 291 (13), 290 (8), 220 (18), 207 (41), 206 (26), 188
(7), 85 (21). Ϫ C24H32 B2O4 (406.1): calcd. C 70.98, H 7.94; found
C 71.40, H 8.05.
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709