Facile synthesis of 3, 3′-disubstituted 2, 2′-binaphthyls by transition-metal-catalyzed double benzannulation

Article abstract of DOI:10.1246/cl.140169

3, 3′-Disubstituted 2, 2′-binaphthyls were prepared by the Cuor Re-catalyzed double benzannulation reaction of 2-(phenylethynyl) benzaldehyde with various butadiynes in the presence of trichloroacetic acid, in moderate to good yields. Acceleration of the second benzannulation was clearly observed.

Full text of DOI:10.1246/cl.140169

Received: February 28, 2014 | Accepted: March 15, 2014 | Web Released: March 20, 2014
CL-140169
Facile Synthesis of 3,3¤-Disubstituted 2,2¤-Binaphthyls
by Transition-metal-catalyzed Double Benzannulation
Rui Umeda,1 Hiromasa Tabata,1 Yoshito Tobe,2 and Yutaka Nishiyama*1
1Faculty of Chemistry, Materials and Bioengineering, Kansai University, Osaka 564-8680
2Graduate School of Engineering Science, Osaka University, Osaka 560-8531
(E-mail: nishiya@kansai-u.ac.jp)
3,3¤-Disubstituted 2,2¤-binaphthyls were prepared by the Cu-
or Re-catalyzed double benzannulation reaction of 2-(phenyl-
ethynyl)benzaldehyde with various butadiynes in the presence
of trichloroacetic acid, in moderate to good yields. Acceleration
of the second benzannulation was clearly observed.
Table 1. Reaction of 2-(phenylethynyl)benzaldehyde (1) with
various butadiynes 2a
O
cat.Cu(OTf)2 or cat.[ReCl(CO)5]
CCl3COOH
R
R
H
+
ClCH2CH2Cl
R
R
80 °C, 9 h
1
2
3
3, Yield [%]b
cat. Cu cat. Re
1,1¤-Binaphthyl (Chart 1) is one of the most versatile
organic frameworks due to its axial chirality. The synthetic
methods of various 1,1¤-binaphthyl derivatives and their
applications, such as chiral ligands and sensors, have been
reported.1 On the other hand, although 2,2¤-binaphthyl deriva-
tives can be promising candidates for chiral frameworks, there
are only a few reports on their synthesis and application.2 From
this point of view, we planned to develop the synthesis of 2,2¤-
binaphthyls by Cu3- or Re4-catalyzed double benzannulation
reactions. Although the synthesis of dihalo-2,2¤-binaphthyl
derivatives by the [4 + 2] benzannulation of 1,4-diphenylbuta-
diyne and 2-(phenylethynyl)benzaldehyde in the presence of
CuX2 (X = Cl and Br) has been shown,5 to the best of our
knowledge, there is no catalytic synthetic method for 2,2¤-
binaphthyl derivatives via the double benzannulation reaction of
2-(phenylethynyl)benzaldehyde with butadiynes.6 In this report,
we describe the catalytic synthetic method for 3,3¤-disubstituted
2,2¤-binaphthyl derivatives by the Cu- or Re-catalyzed reaction
of 2-(phenylethynyl)benzaldehyde with various butadiynes in
the presence of trichloroacetic acid as a Brønsted acid.
Entry
R
1
2
3
4
5
6
7
8
9
10
11
12
13
14
a, Ph
25
53
44
78
b, 4-t-BuC6H4
c, 4-MeOC6H4
d, 2,4,6-triMeC6H2
e, 3,5-di-t-Bu-4-MeOC6H2
f, 4-ClC6H4
61
60
83
94
25
55
trace
<5
24
trace
<5
43
g, 4-FC6H4
h, 1-Naphthyl
i, 2-Naphthyl
j, 9-Anthryl
k, 2-Thienyl
l, 3-Thienyl
23
55
N.D.
N.D.
<10
61
43
N.D.
24
73
58
m, n-Bu
n, (CH3)3Si
31c
aReaction conditions: 1 (0.90 mmol), 2 (0.30 mmol), catalyst
(16 mol %), CCl3COOH (0.90 mmol), and ClCH2CH2Cl
c
(10 mL) at 80 °C for 9 h. bIsolated yields based on 2. 2,2¤-
The reaction of 1,4-diphenylbutadiyne (2a) with 3.0 equiv
of 2-(phenylethynyl)benzaldehyde (1) using [ReCl(CO)5] as
a catalyst in the presence of trichloroacetic acid under our
previous optimized conditions4 gave 3,3¤-diphenyl-2,2¤-bi-
naphthyl (3a) in 44% yield (Entry 1 in Table 1).7,8 When
Cu(OTf)2 instead of the Re complex was used as a catalyst, the
yield of 3a decreased due to the formation of uncharacterized
polymeric products (Entry 1). To study the scope and limitations
of the substrates, various butadiynes 2 were treated with 1
(3.0 equiv) using Cu(OTf)2 or [ReCl(CO)5] as the catalyst in the
presence of trichloroacetic acid; the results are shown in Table 1.
When 1 was allowed to react with 1,4-di(4-t-butylphenyl)-
and 1,4-di(4-methoxyphenyl)butadiynes using [ReCl(CO)5] cat-
alyst, the corresponding 2,2¤-binaphthyl derivatives, 3b and 3c,
Binaphthyl was obtained in 13% yield.
were obtained in 78% and 60% yields, respectively (Entries 2
and 3). Similarly, the Cu-catalyzed double benzannulation of
3b and 3c took place to give the 2,2¤-binaphthyl derivatives
in moderate yields (Entries 2 and 3). For both the Cu and
Re catalysts, the reaction of the sterically hindered butadiyne,
1,4-bis(2,4,6-trimethylphenyl)butadiyne (2d), with 1 efficiently
occurred to give 3d in high yield (Entry 4). For the benzannu-
lation of 1 with 1,4-bis(3,5-di-t-butyl-4-methoxyphenyl)buta-
diyne or dinaphthyl-substituted butadiynes, the yields of 3e, 3h,
and 3i were almost the same as those of 3a (Entries 1, 5, 8, and
9). On the other hand, for the reaction of 1,4-diarylbutadiynes
substituted with chloro and fluoro groups on the phenyl
moieties, 2f and 2g, the yields of the corresponding binaphthyls
3f and 3g were quite low (Entries 6 and 7). The Re-catalyzed
double benzannulation reaction of 1 with 1,4-di(9-anthryl)buta-
diyne (2j) occurred to give 3j in 43% yield; however, the use of
Cu(OTf)2 as a catalyst led to the formation of only uncharac-
terized polymeric materials (Entry 10). Although 2-thienyl-
substituted naphthalene 3k was not formed from 2k, 3-thienyl-
substituted naphthalene 3l was obtained by the reaction of 1,4-
1,1'-Binaphthyl
2,2'-Binaphthyl
Chart 1.
Chem. Lett. 2014, 43, 883–884 | doi:10.1246/cl.140169
© 2014 The Chemical Society of Japan | 883

Table 2. Effect of the ratio of 1 and butadiynes 2a
2,2¤-binaphthyl 3o as the sole product in good yield (Entries 7
and 8), but when 1 was used in the same amount as 2a, only a
trace amount of 4o10 was observed in the case of using both
Cu and Re catalysts (Entries 9 and 10). These results clearly
indicated that the second benzannulation step is much faster than
the first.
In conclusion, the Cu- or Re-catalyzed double benzannula-
tion of 2-(phenylethynyl)benzaldehyde (1) with butadiynes 2
in the presence of trichloroacetic acid gave the corresponding
3,3¤-disubstituted 2,2¤-binaphthyls 3. The possibility of an
asymmetric catalytic reaction using chiral ligands is an intrigu-
ing consideration, which is currently under investigation.
cat.Cu(OTf)2 or cat.[ReCl(CO)5]
R
R
CCl3COOH
1
+
+
ClCH2CH2Cl
R
80 °C, 9 h
2
3
4
Product amount
1
/mmol
Entry
R
Catalyst
/mmol
3
4
1
2
3
4
5
6
7
8
9
a, Ph
a, Ph
a, Ph
a, Ph
a, Ph
a, Ph
o, n-Bu
o, n-Bu
o, n-Bu
o, n-Bu
0.90
0.90
0.60
0.60
0.30
0.30
0.90
0.90
0.30
0.30
Cu
Re
Cu
Re
Cu
Re
Cu
Re
Cu
Re
0.075
0.13
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
traceb
traceb
0.069
0.099
0.050
0.090
0.18
0.22
0.060
0.10
This work was financially supported by the Grant-in-Aid for
Scientific Research on Innovative Areas, the MEXT-Supported
Program for the Strategic Research Foundation at Private
Universities, and the Kansai University Research Grants:
Grant-in-Aid for Encouragement of Scientists.
10
References and Notes
aReaction conditions: 1, 2 (0.30 mmol), catalyst (16 mol %),
and ClCH2CH2Cl (10 mL) at 80 °C for 9 h. CCl3COOH was
1
For selected recent reviews, see: a) M. Terada, Chem.
Commun. 2008, 4097. b) M. Berthod, G. Mignani, G.
Woodward, M. Lemaire, Chem. Rev. 2005, 105, 1801.
c) J. M. Brunel, Chem. Rev. 2005, 105, 857. d) J.-P. Genet,
Acc. Chem. Res. 2003, 36, 908.
b
used in the same amount of 1. Compound 4 (R = n-Bu) was
detected by GC-MS analysis.
2
For selected examples, see: a) T. Fujiwara, Y. Taniguchi, Y.
Katsumoto, T. Tanaka, M. Node, M. Ozeki, M. Yamashita, S.
Hosoi, Tetrahedron: Asymmetry 2012, 23, 981. b) S. Das, A.
Basak, Bioorg. Med. Chem. Lett. 2009, 19, 2815. c) T.
Motomura, H. Nakamura, M. Suginome, M. Murakami, Y.
Ito, Bull. Chem. Soc. Jpn. 2005, 78, 142.
di(3-thienyl)butadiyne (2l) in low yields (Entries 11 and 12).
3,3¤-Di-n-butyl-2,2¤-binaphthyl (3m) was obtained in good yield
by the benzannulation of 1 with the corresponding butadiyne 2m
(Entry 13). The Cu-catalyzed reaction of 1 and 1,4-bis(trimeth-
ylsilyl)butadiyne (2n) produced the mixtures of 3n (31%) and
a desilylated compound, 2,2¤-binaphthyl (13%). On the other
hand, it is important to note that when the Re complex was used,
3,3¤-bis(trimethylsilyl)-2,2¤-binaphthyl (3n) was formed in 58%
yield as the sole product (Entry 14). To confirm the reaction
pathway of the formation of 2,2¤-binaphthyl, 3n was exposed
to 16 mol % of Cu(OTf)2 and 3.0 equiv of CCl3COOH in
CH2ClCH2Cl solvent at 80 °C for 9 h. The protodesilylation of
3n proceeded to give 2,2¤-binaphthyl (38%) together with the
recovered 3n (50%). Based on these results, we suggested that
2,2¤-binaphthyl was formed by the benzannulation reaction of
1 and 2n, followed by the protodesilylation of 3n with TFA
derived from Cu(OTf)2.9
3
4
5
6
a) N. Asao, Synlett 2006, 1645. b) N. Asao, T. Nogami, S.
Lee, Y. Yamamoto, J. Am. Chem. Soc. 2003, 125, 10921.
R. Umeda, K. Kaiba, S. Morishita, Y. Nishiyama,
ChemCatChem 2011, 3, 1743.
Y. Isogai, Menggenbateer, F. N. Khan, N. Asao, Tetrahedron
2009, 65, 9575.
In a preliminary our examination, we have shown the one
example on the Re-catalyzed benzannulation of 1,4-diphen-
ylbutadiyne and 2-(phenylethynyl)benzaldehyde, see ref 4.
Other Lewis acid- or metal complex-catalyzed reaction of
1,4-diphenylbutadiyne (2a) with 2-(phenylethynyl)benzalde-
hyde (1) in the presence of trichloroacetic acid were also
investigated. These results are shown in Supporting Infor-
mation.
Supporting Information is electronically available on the
CSJ-Journal Web site, http://www.csj.jp/journals/chem-lett/
index.html.
The protodesilylation of the trimethylsilyl-substituted aryls
can be achieved by TFA. As an example, see: R. Diercks,
K. P. C. Vollhardt, J. Am. Chem. Soc. 1986, 108, 3150.
7
Next, to estimate the reactivity and selectivity of the triple
bonds of the butadiynes 2, the investigation of the ratio between
1 and 2 was carried out (Table 2). First, when 2 equiv of 1 and
1,4-diphenylbutadiyne (2a) was used, in both cases using the Cu
and Re catalysts, the yield of 3a slightly decreased as compared
to Entries 1 and 2; however, the monobenzannulated product 2-
(phenylethynyl)-3-phenylnaphthalene (4a) was not detected by
8
9
1
both H NMR and GC-MS analysis (Entries 1-4). Even when 1
was used in the same amount as 2a, 4a was not obtained at all
(Entries 5 and 6). The Cu- and Re-catalyzed benzannulation
reaction of 1 (3 equiv) with the asymmetric butadiyne 1-n-butyl-
4-phenylbutadiyne (2o) (3.0 mmol) afforded the corresponding
10 Another isomer, 2-n-butyl-3-(phenylethynyl)naphthalene,
was also observed during the reaction process. Therefore,
we could not explain the reactivity and selectivity of the
triple bonds of 2o.
884 | Chem. Lett. 2014, 43, 883–884 | doi:10.1246/cl.140169
© 2014 The Chemical Society of Japan