Synthesis of tetrasubstituted naphthalenes by palladium-catalyzed reaction of aryl iodides with internal alkynes

Article abstract of DOI:10.1021/jo0346656

The 1:2 coupling of aryl iodides with acetylene-dicarboxylate esters and diphenylacetylene efficiently proceeds in the presence of a palladium catalyst with use of silver carbonate as base to produce the corresponding tetrasubstituted naphthalenes.

Full text of DOI:10.1021/jo0346656

Syn th esis of Tetr a su bstitu ted
Na p h th a len es by P a lla d iu m -Ca ta lyzed
Rea ction of Ar yl Iod id es w ith In ter n a l
Alk yn es
SCHEME 1
Satoshi Kawasaki, Tetsuya Satoh,
Masahiro Miura,* and Masakatsu Nomura
TABLE 1. Rea ction of Iod oben zen e (1a ) w ith Dieth yl
Acetylen ed ica r boxyla te (2a )a
Department of Applied Chemistry, Faculty of Engineering,
Osaka University, Suita, Osaka 565-0871, J apan
miura@chem.eng.osaka-u.ac.jp
Received May 17, 2003
Abstr a ct: The 1:2 coupling of aryl iodides with acetylene-
dicarboxylate esters and diphenylacetylene efficiently pro-
ceeds in the presence of a palladium catalyst with use of
silver carbonate as base to produce the corresponding
tetrasubstituted naphthalenes.
entry
temp (°C)/time (h)
% yield of 3a b
1c
2
100/48
100/24
80/24
5
81
72
25
3
4
d
80/24
5
6
7
120/8
100/24
100/22
90 (75)
79
17
e
Selective synthesis of substituted polycyclic aromatic
hydrocarbons has become increasingly important since
e,f
a
they have been finding increasing application as π-con-
Reaction conditions: [1a ]:[2a ]:[Pd(OAc)2]:[Ag2CO3] ) 1:4:
b
jugated functional materials.1,2 Among modern potential
0.05:1 (in mmol), in DMF under N2. GLC yield based on the
amount of 1a used. Value in parentheses indicates isolated yield.
strategies to prepare condensed aromatics is the metal-
promoted or -catalyzed coupling reaction of mono- or
difunctionalized aromatic substrates with two alkyne
molecules that proceeds via arylmetal species (Scheme
c
d
e
Cs2CO3 was used in place of Ag2CO3. [2a ] ) 2 (mmol). Reaction
in the presence of P(2-furyl)3 (0.15 mmol). f Reaction in o-xylene.
3
-7
the turnover number in the reaction with acetylene-
dicarboxylate esters was only ca. 2. In the course of our
study of transition metal-catalyzed arylation reactions,
we have found an effective protocol for preparing naph-
thalenetetracarboxylates by the palladium-catalyzed cou-
pling, which is reported herein.
When iodobenzene (1a ) was treated with diethyl acety-
lenedicarboxylate (2a ) (4 equiv) in the presence of Pd-
1
).
We recently demonstrated that in the presence of an
7
,9
iridium catalyst, aroyl chlorides (X ) COCl, Y ) H)
efficiently react with dialkyl- and diarylacetylenes ac-
companied by decarbonylation to produce the correspond-
ing tetrasubstituted naphthalenes and anthracenes.7
However, the reaction with electron-deficient alkynes,
such as acetylenedicarboxylates, did not proceed. In
contrast to the iridium catalysis, it was reported that
palladium species can mediate the 1:2 coupling of iodo-
(
2 2 3
OAc) (5 mol %) with Cs CO (1 equiv), which is an
8
effective base for the 1:1 coupling with dialkylacetylenes,
in DMF at 100 °C for 48 h, a small amount of tetraethyl
naphthalene-1,2,3,4-tetracarboxylate (3a) (5%) was formed
6
a
benzene with the latter alkynes, while no naphthalenes
are formed with use of dialkylacetylenes.4
c,6b,8
However,
(
entry 1 in Table 1). Interestingly, use of Ag
2 3
CO in place
of Cs CO remarkably improved the yield of 3a up to 81%
2
3
(
1) Harvey, R. G. Polycyclic Aromatic Hydrocarbons; Wiley-VCH:
New York, 1996.
2) Watson, M. D.; Fethtenk o¨ tter, A.; M u¨ llen, K. Chem. Rev. 2001,
01, 1267.
(entry 2). While lowering temperature to 80 °C only
slightly affected the yield (entry 3), decreasing the
amount of 2a to 2 equiv considerably retarded the
reaction (entry 4). At a higher temperature of 120 °C, 1a
was consumed completely within 8 h to give 3a in 90%
yield (entry 5). It is noted that in each run, detectable
byproduct derived from 2a by GC-MS was only a trace
amount of its trimer.
Table 2 summarizes the results for the reactions of
2 3
various aryl iodides with alkyne 2a , using Ag CO as
base. In the reaction of 4-iodotoluene (1b) at 100 °C,
tetraethyl 6-methylnaphthalene-1,2,3,4-tetracarboxylate
(
1
(
3) X ) Y ) halogen: (a) Takahashi, T.; Hara, R.; Nishihara, Y.;
Kotora M. J . Am. Chem. Soc. 1996, 118, 5154. (b) Takahashi, T.;
Kitamura, M.; Shen, B.; Nakajima, K. J . Am. Chem. Soc. 2000, 122,
1
2876. (c) Takahashi, T.; Li, Y.; Stepnicka, P.; Kitamura, M.; Liu, Y.;
Nakajima, K.; Kotora M. J . Am. Chem. Soc. 2002, 124, 576. (d) Bennett,
M. A.; Hockless, C. R.; Wenger, E. Organometallics 1995, 14, 2091. (e)
Bowles, D. M.; Anthony, J . E. Org. Lett. 2000, 2, 85.
(
3
4) X ) OTf, Y ) SiMe : (a) Pe n˜ a, D.; Escudero, S.; P e´ rez, D.;
Guiti a´ n, E.; Castedo, L. Angew. Chem., Int. Ed. 1998, 37, 2659. (b)
Pe n˜ a, D.; P e´ rez, D.; Guiti a´ n, E.; Castedo, L. J . Org. Chem. 2000, 65,
6
944. (c) Yoshikawa, E.; Radhakrishnan, K. V.; Yamamoto, Y. J . Am.
Chem. Soc. 2000, 122, 7280.
5) X ) CrPh
(
2
, Y ) H: (a) Whitesides, G. M.; Ehmann, W. J . J .
Am. Chem. Soc. 1970, 92, 5625. (b) Herwig, W.; Metlesics, W.; Zeiss,
H. J . Am. Chem. Soc. 1959, 81, 6203.
(
(
3b) was obtained in a comparable yield to that of 3a
entry 1), but unexpectedly, it was decreased at 120 °C
(
6) X ) I, Y ) H: (a) Sakakibara, T.; Tanaka, Y.; Yamasaki, T.-I.
Chem. Lett. 1986, 797. (b) Wu, G.; Rheingold, A. L.; Feib, S. L.; Heck,
R. F. Organometallics 1987, 6, 1941.
(entry 2). Thus, other 4-substituted iodobenzenes 1c-e
(
7) X ) COCl, Y ) H: Yasukawa, T.; Satoh, T.; Miura, M.; Nomura,
M. J . Am. Chem. Soc. 2002, 124, 12680.
8) Pivsa-Art, S.; Satoh, T.; Miura, M.; Nomura, M. Chem. Lett. 1997,
23.
(9) (a) Miura, M.; Nomura, M. In Cross-Coupling Reactions; Miyaura,
N., Ed.; Springer: Berlin, Germany, 2002; p 211. (b) Okazawa, T.;
Satoh, T.; Miura, M.; Nomura, M. J . Am. Chem. Soc. 2002, 124, 5286.
(
8
1
0.1021/jo0346656 CCC: $25.00 © 2003 American Chemical Society
Published on Web 07/31/2003
6
836
J . Org. Chem. 2003, 68, 6836-6838

TABLE 2. Rea ction of Ar yl Iod id es 1 w ith Dieth yl
TABLE 3.a Rea ction of Iod oben zen e (1a ) w ith Alk yn es
2b a n d 2c
a
Acetylen ed ica r boxyla te (2a )
a
The reaction was carried out with 1a (1 mmol), Pd(OAc)2 (0.05
b
mmol), P(2-furyl)3 (0.15 mmol), and Ag2CO3 (1 mmol). GC yield
based on 1a used. Value in parentheses indicates isolated yield.
c
Without P(2-furyl)3. d 2:1 coupling product (7%) was also formed.
Table 1). Dimethyl acetylenedicarboxylate (2b) reacted
with 1a to give naphthalene 6, as expected (entry 1 in
Table 3).
It has been reported that the palladium-catalyzed
reaction of 1a with diphenylacetylene (2c) gives rise to
6
b
not only 1:2 product (1,2,3,4-tetraphenylnaphthalene, 7)
but also 2:110 and 1:1 products (9,10-diphenylphenan-
threne and 9-benzylidenefluorene, respectively). While
the latter two compounds were prepared with good yields
11
by employing appropriate conditions, it appeared to be
difficult to obtain 7 selectively.6
b,10b
Consequently, the
reaction was carried out under the present conditions.
It was of interest that treatment of 1a with 2c (2 equiv)
3
in the presence of P(2-furyl) selectively gave 7 (44%) as
a
Reaction conditions: [1]:[2a ]:[Pd(OAc)2]:[Ag2CO3] ) 1:4:0.05:1
b
the single product, no other coupling products being
formed (entry 2 in Table 3). It was also found that use of
o-xylene as solvent in place of DMF improved both the
reaction rate and product yield. Thus, 7 was produced
exclusively in 87% yield within 8 h (entry 3). In this case,
addition of the phosphine was essential to make the
(
in mmol), in DMF at 100 °C under N2. GC yield based on 1 used.
Value in parentheses indicates isolated yield. Reaction at 120
C. P(2-furyl)3 (0.15 mmol) was added.
c
d
°
(
3
R ) OMe, Cl, and Br) were reacted at 100 °C (entries
-5). In each run, the corresponding naphthalene was
obtained in good yield. The bromo moiety in 1e was not
attacked under these conditions. The reaction of 2-iodo-
thiophene (1f) yielded benzothiophene 3f, although the
yield was low (entry 6).
reaction catalytic (entry 4). The reaction with Cs
2 3
CO in
place of Ag CO was relatively slow and was accompanied
2
3
by the formation of the 2:1 coupling product (entry 5).
A plausible mechanism for the reaction of aryl iodide
1
with alkyne 2 is illustrated in Scheme 2 (neutral
Iodonaphthalenes were found to react with 2a to form
tricyclic compounds as expected (entries 7 and 8). The
reaction of 2-iodonaphthalene (1g) gave tetraethyl an-
thracene-1,2,3,4-tetracarboxylate (3g) as the major prod-
uct along with a small amount of the corresponding
phenanthrene 4. On the other hand, the reaction of
ligands are omitted). Oxidative addition of 1 to Pd(0)
species generated in situ gives an arylpalladium(II)
intermediate A. Then, syn-addition of the Ar-Pd bond
in A to the triple bond of 2 to give a vinylpalladium
species B, followed by cyclopalladation affords a five-
membered palladacycle C. The subsequent reaction with
2
and reductive elimination affords the corresponding
1
-iodonaphthalene (1h ) preferred 1:1 coupling to 1:2
annulated product with regeneration of Pd(0) species. As
coupling to produce diethyl acenaphthylene-1,2-dicar-
boxylate (5) as the major product along with 4. It is noted
that for the reactions of 1c and 1f-h , P(2-furyl) was
3
7
in the iridium-catalyzed naphthalene synthesis, partici-
pation of another route, which involves successive inser-
added as ligand, so that the product yields were improved
by 6-13%. However, no positive effect of the posphine
addition was observed in the other runs (e.g. entry 6 in
(
10) (a) Dyker, G.; Kellner, A. Tetrahedron Lett. 1994, 35, 7633. (b)
Dyker, G.; Kellner, A. J . Organomet. Chem. 1998, 555, 141.
(11) Larock, R. C.; Tian, Q. J . Org. Chem. 2001, 66, 7372.
J . Org. Chem, Vol. 68, No. 17, 2003 6837

SCHEME 2
Table 1) and the ligand showed no or only somewhat
positive effects. It is worth noting that in the reaction of
1
-iodonaphthalene (1h ) (entry 8 in Table 2), cyclopalla-
dation occurs preferably at its 8-position rather than
-position.13 A six-membered palladacycle thus formed
2
undergoes reductive elimination prior to the reaction with
the second alkyne molecule to afford 5 predominantly.
In summary, we have developed a useful method for
the palladium-catalyzed coupling of aryl iodides with
acetylene dicarboxylate esters as well as diphenylacety-
lene to produce tetrasubstituted naphthalene derivatives.
The use of an appropriate base such as Ag CO has been
2 3
found to be critical to conduct the reaction efficiently and
selectively.
Ack n ow led gm en t. This work was supported by
Grant-in-Aids from the Ministry of Education, Culture,
Sports, Science and Technology, J apan.
tion of two molecules of 2 and the subsequent cyclopal-
ladation to form a seven-membered palladacycle D,
cannot be excluded.
Su p p or tin g In for m a tion Ava ila ble: Standard experi-
mental procedure and characterization data for compounds
3b-g and 4-7. This material is available free of charge via
the Internet at http://pubs.acs.org.
Anyway, Ag
2 3
CO appears to remove iodide ligand from
the Pd center to promote alkyne insertion as well as
1
2
cyclopalladation. However, the origins of significant
effects with use of o-xylene and P(2-furyl) in the reaction
3
J O0346656
with alkyne 2c are not definitive at this stage, since in
the case of 2a , the solvent was not preferable (entry 7,
(13) (a) Satoh, T.; Kawamura, Y.; Miura, M.; Nomura, M. Angew.
Chem., Int. Ed. Engl. 1997, 36, 1740. (b) Satoh, T.; Inoh, J .; Kawamura,
Y.; Kawamura, Y.; Miura, M.; Nomura, M. Bull. Chem. Soc. J pn. 1998,
71, 2239.
(
12) For a review, see: Echavarren, A. M.; G o´ mez-Lor, B.; Gonz a´ lez,
J . J .; de Frutos, OÄ . Synlett 2003, 585.
6
838 J . Org. Chem., Vol. 68, No. 17, 2003