A new and efficient method for the synthesis of 2,2′-dibromo-1,1′-binaphthyl under microwave irradiation

Article abstract of DOI:10.1081/SCC-120022163

A very simple and efficient method to prepare 2,2′-dibromo-1,1′-binaphthyl via two-step procedure from β-naphthol in good yield under microwave irradiation is described.

Full text of DOI:10.1081/SCC-120022163

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A New and Efficient Method for the Synthesis of 2,2′-
Dibromo-1,1′-binaphthyl Under Microwave Irradiation
a
a
a
a
Li-wen Xu , Fu-wei Li , Chun-gu Xia & Wei Sun
a
State Key Laboratory of Oxo Synthesis and Selective Oxidation, Lanzhou Institute of
Chemical Physics, Chinese Academy of Science, Lanzhou, P.R. China
Published online: 19 Aug 2006.
To cite this article: Li-wen Xu , Fu-wei Li , Chun-gu Xia & Wei Sun (2003) A New and Efficient Method for the Synthesis of
,2′-Dibromo-1,1′-binaphthyl Under Microwave Irradiation, Synthetic Communications: An International Journal for Rapid
2
Communication of Synthetic Organic Chemistry, 33:16, 2763-2767, DOI: 10.1081/SCC-120022163
To link to this article: http://dx.doi.org/10.1081/SCC-120022163
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Õ
SYNTHETIC COMMUNICATIONS
Vol. 33, No. 16, pp. 2763–2767, 2003
A New and Efficient Method for the
Synthesis of 2,2 -Dibromo-1,1 -binaphthyl
Under Microwave Irradiation
0
0
Li-wen Xu, Fu-wei Li, Chun-gu Xia,* and Wei Sun
State Key Laboratory of Oxo Synthesis and Selective
Oxidation, Lanzhou Institute of Chemical Physics,
Chinese Academy of Science, Lanzhou, P.R. China
ABSTRACT
0
0
A very simple and efficient method to prepare 2,2 -dibromo-1,1 -
binaphthyl via two-step procedure from b-naphthol in good yield
under microwave irradiation is described.
The most well-known example of an axially chiral ligand is the
0
0
diphosphine, 2,2 -bis(diphenylphosphino)-1,1 -binaphthyl (BINAP), a
C -symmetric triaryldiphosphine. The synthesis and first application
2
[
of which were reported by Noyori and Takaya in 1980, this ligand
1]
*
Correspondence: Chun-gu Xia, State Key Laboratory of Oxo Synthesis and
Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy
of Science, Lanzhou, 73000, P.R. China; E-mail: c.gxia@ns.lzb.ac.cn.
2
763
DOI: 10.1081/SCC-120022163
Copyright & 2003 by Marcel Dekker, Inc.
0039-7911 (Print); 1532-2432 (Online)
www.dekker.com

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2
764
Xu et al.
is very effective in inducing asymmetry by intra-complex steric interac-
tions between the bulkyl triarylphosphine system and the reactants
bound to the metal. Its application in asymmetric catalysis has been
[2]
[3]
reviewed in 1990 and 1992 and subseqently its use has been
well documented in numerous textbooks. Optically pure BINAP
was obtained by stereospecific transformation of optically active
0
0
2
,2 -dibromo-1,1 -binaphthyl. The phosphine is also synthesized by the
optical resolution of (ꢀ) BINAP. The procedure is the best preparative-
scale synthesis of both enantiomers of BINAP in an optically pure
starting from accessible reacemic 2,2 -dibromo-1,1 -binaphthyl. We
have been working in developing new synthetic methods for the
0
0
0
0
preparation of substituted 2,2 -dibromo-1,1 -binaphthyl only using
microwave irradiation from b-naphthol.
Excellent reviews have been published on various aspects of
[
4]
microwave-assisted chemistry. These reviews were highlight micro-
wave-assisted rapid organic transformating of particular importance in
organic chemistry and pharmaceutical chemistry and discussed some of
the most recently disclosed applications to medicinal and combinational
[5]
chemistry. Microwave technique has been widely used for many organic
reactions, such as Diel–Alder, esterification, etherification, oxidation,
hydrolysis, cyclization, claisen, Reformatsky, Knoevenagel, and
[
6]
Bischler Napieraski reactions. Microwave irradiation produces efficient
internal heating transfer (in situ heating), resulting in even heating
throughout the sample, as compared with the wall heat-transfer that
[
7]
occurs under an oil bath is applied as an energy source.
In this article, we reported a new, rapid, practical, and high-yielding
0
0
method for the total preparation of 1,1 -binaphthalene-2,2 -diol (BINOL)
0
0
and 2,2 -dibromo-1,1 -binaphthyl via microwave irradiation respectively
Sch. 1).
The classical approach to give 1,1 -binaphthalene-2,2 -diol (BINOL)
(
0
0
relies on the oxidative coupling of b-naphthol. A number of mild oxi-
dants have been reported to facilitate this reaction, in particular, Fe
[
8]
(
III), Cu (II) salts. BINOLalso can be obtained by oxidative coupling
ii) microwave
i) microwave
FeCl3/SiO2
PPh Br
Br
OH
3 2
HO
Br
OH
1
2
3
Scheme 1.

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0
0
2
,2 -Dibromo-1,1 -binaphthyl
2765
of 2-hydroxynaphthalane in the presence of transition metal complexes,
[
9]
such as FeCl ꢁ6H O. However, the classical methods need longer
3
2
times and complexed work-up procedures. Carrying out reactions
using microwave heating of b-naphthol and ferric chloride
(
shorter reaction times and afford the BINOLin more excellent yields.
FeCl ꢁ6H O) under solvent-free conditions, has major advantages of
3
2
[
10]
Although Villemin and Sanvaget
have reported that microwave irra-
diation acceleted greatly the addition of naphthol with FeCl ꢁ6H O
3
2
without solvent, the results are difficult to reproduce when the reactions
are conducted with small samples. In this report, we improved the
method by the addition of silical gel. It has the advantages of facile
work-up procedures, and the good results is easy to reproduce. The
results for prepared the BINOLlisted in Table 1. It is worth mentioning
that in the absence of silica gel the yield is poor.
0
0
The 2,2 -dibromo-1,1 -binaphthyl is a useful and versatile building
block for the synthesis of BINAP. It has been prepared by the reaction
triphenylphosphinebromine complex with BINOL. However, the bromi-
ꢂ
nation reaction involves the use of high bath temperature (340 C) and
0
0
long reaction times to obtain the 2,2 -dibromo-1,1 -binaphthyl in
appropriate yields.
[11]
To our surprise, the use of microwave technology
has not been decribed in relation to the type of bromination reaction.
Using microwave irradiation, we obtain the title compound in good
yield. Microwave irradiation by 10 min at 800 W of power of a mixtures
0
of BINOL, triphosphine, and bromine yields over 50% of 2,2 -dibromo-
0
1,1 -binaphthyl. At 800 W and an additional 10 min of irradiation, the
Table 1. Synthesis of BINOLunder microwave irradiation.
Power
(W)
Time
(s)
a
c
Yield (%)
Entry
1
Ratio of reagents
1/2
200
50
60
120
120
60
70
85
89
92
48
93
92
96
2
2
3
1/2.2
1/2.5
250
250
b
2
00
60
60
4
5
6
1/3
1/3.5
1/4
250
250
250
60
60
a
The weight ratio of b-naphthol and ferric chloride (FeCl
3
2
Á6H O).
b
No silica gel.
Isolated yield.
c

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Xu et al.
best yields increase to 60%. It is important that the last trace of
ꢂ
acetonitrile is removed at a bath temperature of 200 C before micro-
wave irradiation. From the results of a comparative study of the syn-
0
0
thesis of the 2,2 -dibromo-1,1 -binaphthyl by the classical method and
microwave irradiation, it is clear that the reaction time is reduced from
several hours to only a few minutes by using microwave irradiation,
indicating that microwaves plays an important role in the rate enhance-
ment.
0
0
In conclusion, BINOLand 2,2 -dibromo-1,1 -binaphthyl promoted
by microwave irradiation was a facile, high yield and rapid reaction with
easy purification that could be as a path for synthesis of these title
compounds.
EXPERIMENT
All commercially available regeant b-naphthol, ferric chloride
(
FeCl ꢁ6H O), triphosphine, bromine, silica gel (200–300 mesh) were
3
2
used as received from the suppliers. The acetonitrile was cautiously dis-
tilled from phophorus pentoxide. All of the products are known com-
pounds and were identified by comparison of their spectral data (IR,
1
13
H NMR, C NMR). Melting points were obtained in a modified
Koffler apparatus and were uncorrected. Microwave assisted reactions
were carried out using a Galanz microwave oven model WP800SL23 of
variable radiofrequency.
0
0
1
,1 -Binaphthalene-2,2 -diol (BINOL) (2). The premixed mixture of
b-naphthol, ferric chloride (FeCl ꢁ6H O), and silica gel (200–300 mesh)
3
2
which was placed in a flask inside an modified household Galanz micro-
wave oven for the specified time at the power of 200 W or 250 W (see
Table 1). After the reaction mixture is cooled, the crude product was
directly purified via flash chromatography, using acetone/petroleum
ether as the eluting solvent, yielding the title compound BINOLin high
ꢂ
yield. M.p. 217–218 C.
0
0
2
,2 -Dibromo-1,1 -binaphthyl (3). A 250 mLthree-necked, round-
bottomed flask is equipped with an efficient mechanical stirrer, thermom-
eter, and a droping funnel. The flask is charged with 24 g (91.5 mmol) of
triphenylphosphine and 50 mLof dry acetonitrile. the solution is stirred
and cooled in an ice bath and 15.5 g (5 mL, 96.9 mmol) of bromine is
0
added dropwise over a period of 10 min. Then 12 g (42 mmol) of 1,1 -
0
binaphthalene-2,2 -diol (BINOL) is added to the solution. The viscous
ꢂ
slurry is stirred at 60 C for 30 min. After all the acetonitrile has been
removed, the reaction was carried out in microwave oven and irradiation

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0
0
2
,2 -Dibromo-1,1 -binaphthyl
2767
for the special time (10–20 min) at its full power of 800 W. On completion
of the reaction, as determined by TLC (hexane:benzene, 4:1). The reac-
tion mixture is added 100 mLCelite with stirring. The mixture is
extracted with three 50 mLportions of a boiling 1:1 mixture of a benzene
and hexane. The combined extracts are evaporated to give an orange-
yellow viscous crude product. Recrystallization from ethanol affords
0
0
the pure 2,2 -dibromo-1,1 -binaphthyl as yellow, fine crystals (10.4 g,
ꢂ
ꢂ
[11]
0% yield). M.p. 185 C (Lit. M.p. 180 C).
6
ACKNOWLEDGMENTS
The authors thank the Natural Science Founder of National for
financial support of the work.
REFERENCES
. Miyashita, A.; Yasuda, A.; Takaya, H.; Toriumi, K.; Ito, T.;
1
Souchi, T.; Noyori, R. J. Am. Chem. Soc. 1980, 102, 7932.
. Noyori, R.; Takaya, H. Acc. Chem. Rev. 1990, 23, 345.
. Rosini, C.; Franzini, L.; Raffaelli, A.; Salvaderi, P. Synthesis 1992,
2
3
5
03.
. (a) Mingos, D.M.P.; Baghurst, D.R. Chem. Soc. Rev. 1991, 20, 1;
b) Elander, N. Chem. Soc. Rev. 2000, 29, 239; (c) Larhed, M.;
Hallberg, A. Drug Discovery Today 2001, 6, 406.
. (a) Rajender, S.V.; Kannan, P.N. Tetrahedron Letters 1999, 40,
4
5
6
(
6177–6180; (b) Holger, G.; Werner, R.T. Tetrahedron Letters
1998, 39, 5509.
. (a) Abramovitch, R.A. Org. Prep. Proc. Int. 1991, 23, 685; (b)
Bratulescu, G.; Bigot, Y. Le.; Delmas, M. Synth. Commun. 2001,
31, 3309.
7
8
. Strass, C.R.; Trainor, R.W. Aust. J. Chem. 1995, 48, 1665.
. (a) Vyskocil, S.; Smrcina, M.; Lorenl, M. J. Org. Chem. 2001, 66,
1359; (b) Nakajima, M.; Hashimoto, S.; Nuji, M.; Koga, M. Chem.
Pharm. Bull. 1998, 46, 1814.
9
. (a) Jacques, J.; Fouquey, C. Organic Synthesis 1989, 67, 1; (b) Jiang,
P.; Lu, S. J. Synth. Commun. 2001, 31, 131; (c) Toda, F.; Tanaka,
K.; Iwata, S. J. Org. Chem. 1989, 54, 3007.
10. Villemin, D.; Sanvaget, F. Synlett 1994, 435.
11. Pichat, L.; Clement, J. Bull. Soc. Chim. France 1961, 525–528.
Received in Japan October 26, 2002

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