Ring contraction of 1,2-dihydronaphthalenes promoted by thallium(III) in acetonitrile: A diastereoselective approach to indanes

Article abstract of DOI:10.1055/s-0028-1083308

Trans-1,3-Disubstituted indanes are conveniently accessed by a stereoselective ring contraction of 1,2-dihydronaphthalenes upon treatment with thallium(III) nitrate (TTN) in acetonitrile. Under these conditions, the oxidative rearrangement of either di- or trisubstituted double bonds is possible. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-0028-1083308

PAPER
385
Ring Contraction of 1,2-Dihydronaphthalenes Promoted by Thallium(III) in
Acetonitrile: A Diastereoselective Approach to Indanes
R
H
ingContractiono
e
f
1,2-Dihy
l
e
thalenes
P
n
romotedby
T
a
hallium(III) M. C. Ferraz, Vânia M. T. Carneiro, Luiz F. Silva, Jr.*
Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970, São Paulo SP, Brazil
E-mail: luizfsjr@iq.usp.br
Received 20 August 2008; revised 30 September 2008
tions, the formation of addition products was not ob-
served, and a mixture of ketones 5 and 6 was isolated
Scheme 2, Table 1, entry 1). Presumably, ketone 5 is
Abstract: trans-1,3-Disubstituted indanes are conveniently access-
ed by a stereoselective ring contraction of 1,2-dihydronaphthalenes
upon treatment with thallium(III) nitrate (TTN) in acetonitrile.
(
Under these conditions, the oxidative rearrangement of either di- or formed through direct rearrangement of the oxythallated
5
trisubstituted double bonds is possible.
adduct 7 (Scheme 2, path a), while tetralone 6 might arise
from competitive formation of the epoxide 8, ring opening
to the tertiary benzylic cation 9, and finally 1,2-hydride
Key words: thallium(III) nitrate, carbocycles, indanes, ring con-
tractions, oxidative rearrangements
6
migration (path b). The result with olefin 3 prompted us
to study the reaction of other 1,2-dihydronaphthalenes. To
our delight, the reaction of 10 with thallium(III) nitrate in
acetonitrile gave only the desired ring contraction product
The indane ring system is present in several compounds
1
a
with remarkable biological activity. Consequently, new
approaches to obtain indanes are constantly under investi-
gation. Particularly challenging has been the stereoselec-
1
1, in 80% yield, as a 21:1 (trans/cis) mixture of diaste-
reomers (Table 1, entry 2). The selective formation of the
1
trans-isomer agrees with the mechanism previously dis-
tive synthesis of substituted indanes. To this end, we
2
c
cussed. The presence of an alkyl group at position 1 fa-
vors the ring contraction, explaining the high yield of the
reported that trans-1,3-disubstituted indanes, such as 2,
are obtainable by the ring contraction of readily available
4b
rearrangement product 11. The reaction of 12 was per-
formed in a similar manner, affording the ring contraction
product 13 in 63% yield (Table 1, entry 3). However, in
this case, the aromatization product 14 was also obtained
as a minor component.2b The trans-1,3-disubstituted in-
dane 16 was the main product in the oxidation of 15
1
,2-dihydronaphthalenes in the presence of thallium(III)
nitrate (TTN) in methanol or in trimethyl orthoformate
2
(
TMOF) (Scheme 1). However, products of addition of
methanol, such as 4, are isolated for substrates with a
2
a
trisubstituted double bond (Scheme 1). Herein, we de-
scribe that indanes can be obtained from 1,2-dihydronaph-
thalenes bearing either di- or trisubstituted double bonds
if thallium(III) nitrate is used in acetonitrile, instead of
methanol, thus overcoming the drawback mentioned
above.
(
Table 1, entry 4), although the yield was lower than that
from 10 and from 12. The time required for the complete
consumption of the starting olefin also varied consider-
ably for 10, 12, and 15 (10 min, 6 h, and 24 h, respective-
ly). Considering that thallium(III)-mediated ring
contraction is sensitive to steric and electronic effects,2
the lower yield and reactivity of 12 when compared to 10
can be explained by the higher steric hindrance of the
group attached to the double bond (i-Pr vs Me). The dif-
ference of reactivity between 15 and 10 can be explained
by both steric and electronic effects.
,7
MeO
OMe
TTN (1.1 equiv), MeOH
0
°C, 5 min
8
7%
1
2
4
OMe
OMe
TTN (1.7 equiv), MeOH
30 °C, 15 min
a
OHb X a, b
COMe
–
Tl
X
TTN⋅3H2O
path a
6
9%
3
a
3
a, b
–
H+
X = ONO2
7
Scheme 1
5
path b
+
H
Inspired by previous work on oxidations of olefins with
O
H
O
3
4
thallium(III) or iodine(III) in acetonitrile, we decided to
investigate the behavior of 1,2-dihydronaphthalene 3 in
this solvent (Scheme 2). Fortunately, under these condi-
+
OH
– H+
8
9
6
Scheme 2
SYNTHESIS 2009, No. 3, pp 0385–0388
x
x
.
x
x
.2
0
0
9
Advanced online publication: 09.01.2009
DOI: 10.1055/s-0028-1083308; Art ID: M04508SS
Georg Thieme Verlag Stuttgart · New York
©

3
86
H. M. C. Ferraz et al.
PAPER
Table 1 Reactions of 1,2-Dihydronaphthalenes with Thallium(III) Nitrate Trihydrate in Acetonitrilea
b
Entry
1
Substrate
Product(s)
Time
Yield (%)
O
O
10 min
70 (5/6 = 3:1)
+
3
6
5
O
2
3
10 min
80 (trans/cis = 21:1)
10
11
O
i-Pr
i-Pr
i-Pr
6 h
63 (13), 5 (14)
+
12
13
14
O
Ph
Ph
4
5
24 h
40
1
5
1
6
CHO
10 min
30 min
97c
1
7
1
8
O
OH
ONO2
Ha
6
76 (20), 4 (21)
+
19
20
21
a
Reagents and conditions: substrate (1 equiv), 3-Å MS (0.5 g/g substrate), TTN·3H O (1.1 equiv), MeCN, 0 °C.
Isolated yield.
Crude product.
2
b
c
After investigating the behavior of a series of trisubstitut- In summary, indanes can be obtained diastereoselectively
ed olefins, we decided to verify if acetonitrile would also by the reaction of 1,2-dihydronaphthalenes with thalli-
be a good solvent for the ring contraction of disubstituted um(III) in acetonitrile. This solvent appears to be more ef-
substrates. Indeed, when the 1,2-dihydronaphthalene 17 ficient than methanol for the rearrangement of olefins.
was treated with thallium(III) nitrate in acetonitrile, in- Finally, these conditions lead to higher isolated yields
dane 18 was obtained in high yield (Table 1, entry 5). The than obtained in an analogous protocol using iodine(III).4b
formation of an aldehyde (as 18) instead of a ketal (such
as 2, cf. Scheme 1) may be an advantage, because a depro-
tection step is avoided. Finally, thallium(III) nitrate also
Warning: Thallium salts are toxic and must be handled with care.
2
c
TTN was used as received. MeCN was distilled from CaH and
2
induced ring contraction of a seven-membered-ring ana- stored over molecular sieves. Melting points are uncorrected. Col-
8
logue, as was demonstrated with the olefin 19, which umn chromatography was performed using silica gel 200–400
mesh. TLC analysis was performed on silica gel plates, using phos-
gave rise to ketone 20 in 76% yield (Table 1, entry 6). A
small amount of the addition product 21 was also isolated.
phomolybdic acid, vanillin or p-anisaldehyde solution for visualiza-
1
tion. IR spectra were measured on a Perkin-Elmer 1750-FT. H
The relative configuration of 21 was inferred from the
1
3
NMR (300 MHz) and C NMR (75 MHz) spectra of samples in
2
,9
mechanism of the reaction. Nitrate 21 has a characteris-
CDCl were obtained on a Bruker spectrometer. Gas chromatogra-
3
1
2b
tic signal at d = 4.7 for H in the H NMR spectrum.
a
phy was carried out on HP 6890 series II and Shimadzu 2010 instru-
Synthesis 2009, No. 3, 385–388 © Thieme Stuttgart · New York

PAPER
Ring Contraction of 1,2-Dihydronaphthalenes Promoted by Thallium(III)
387
ments. HRMS analysis was conducted on a Bruker Daltonics
brine and dried (MgSO ). The soln was concentrated under reduced
4
Microtof Electrospray apparatus. Compounds 3, 10, and 17 were
prepared by literature procedures.
pressure and the residue was purified by flash chromatography
2
b,c,4b
13
14
(Et O–hexanes, 1:9); this gave a 3:1 mixture of 5 and 6 as a col-
2
orless oil; yield: 0.112 g (70%).
4
-Isopropyl-1-methyl-1,2-dihydronaphthalene (12); Typical
Procedure for Grignard Reactions To Prepare the Substrates
A soln of 4-methyl-1-tetralone (2.40 g, 15.0 mmol) in anhyd Et O
1-(trans-1-Methyl-2,3-dihydro-1H-inden-3-yl)ethanone (11)
The typical procedure was followed, but 10 (0.158 g, 1.00 mmol)
was used in place of 3. The residue was purified by flash chroma-
2
(6 mL) was added to a soln of i-PrMgBr [prepared from i-PrBr (7.38
4
b
g, 60.0 mmol), Mg (1.44 g, 59.2 mmol), and I (some crystals) in an-
hyd Et O (18 mL)]. The mixture was stirred for 20 h at reflux. After
tography (EtOAc–hexanes, 0–5% gradient); this gave 11 as a cis/
2
1
trans mixture (1:21, by H NMR after purification). Yield: 0.139 g
2
that, a soln of 6 M HCl was added dropwise at 0 °C until the pH was
(80%); colorless oil.
2
–3. The soln was stirred for 1 h. The organic layer was extracted
2
-Methyl-1-(trans-1-methyl-2,3-dihydro-1H-inden-3-yl)pro-
with Et O (90 mL), washed with a sat. aq soln of Na S O (30 mL)
and brine (30 mL) and dried (MgSO ). The soln was concentrated
under reduced pressure and the residue was purified by flash chro-
matography (hexanes); this gave 12 as a colorless oil; yield: 1.08
2
2
2
3
pan-1-one (13)
4
The typical procedure was followed, but 12 (0.186 g, 1,00 mmol)
was used in place of 3. The mixture was stirred for 6 h at 0 °C. The
residue was purified by flash chromatography (EtOAc–hexanes,
1
0
1
0
g (39%). (The NMR data of 12 were not previously reported. )
0
–5% gradient) giving 13 and 1-isopropyl-4-methylnaphthalene
1
H NMR (300 MHz, CDCl ): d = 1.15 (d, J = 6.6 Hz, 3 H), 1.16 (d,
15
3
(
0
14), both as colorless oils; yield (13): 0.127 g (63%); yield (14):
.009 g (5%).
J = 6.6 Hz, 3 H), 1.20 (d, J = 6.9 Hz, 3 H), 2.01–2.11 (m, 1 H),
2
5
H).
.35–2.45 (m, 1 H), 2.82 (sext, J = 6.9 Hz, 1 H), 2.90–3.02 (m, 1 H),
.79 (td, J = 4.7, 1.2 Hz, 1 H), 7.16–7.23 (m, 3 H), 7.30–7.34 (m, 1
Indane 13
–1
IR (film): 2964, 2929, 2871, 1709, 1466, 1052, 755 cm .
1
3
C NMR (75 MHz, CDCl ): d = 19.7, 22.1, 22.3, 28.0, 30.9, 32.3,
1
3
H NMR (500 MHz, CDCl ): d = 1.06 (d, J = 6.5 Hz, 3 H), 1.13 (d,
3
1
19.7, 122.6, 126.0, 126.2, 126.6, 134.1, 141.9, 142.0.
J = 7.0 Hz, 3 H), 1.28 (d, J = 7.0 Hz, 3 H), 1.83 (dt, J = 12.5, 8.7 Hz,
1
1
H), 2.55 (ddd, J = 12.5, 7.5, 3.5 Hz, 1 H), 2.93 (sept, J = 7.0 Hz,
H), 3.38–3.46 (m, 1 H), 4.26 (dd, J = 8.7, 3.5 Hz, 1 H), 7.15–7.18
1
-Methyl-4-phenyl-1,2-dihydronaphthalene (15)
The reaction was performed as described above for 12. A mixture
of 4-methyl-1-tetralone (0.641 g, 4.00 mmol) and PhMgBr [pre-
pared from PhBr (0.819 g, 5.22 mmol), Mg (0.125 g, 5.21 mmol),
and I (some crystals) in anhyd Et O (2 mL)] was stirred for 2 h at
reflux. The crude product was purified giving 15 as a colorless oil;
yield: 0.704 g (80%). (The NMR data of 15 were not previously re-
(m, 1 H), 7.20–7.25 (m, 3 H).
1
3
C NMR (126 MHz, CDCl ): d = 18.4, 18.9, 20.2, 38.1, 38.4, 38.9,
3
5
4.9, 123.8, 124.5, 126.4, 127.5, 140.8, 149.4, 214.5.
2
2
1
1
MS: m/z (%) = 131 (100), 202 (8) [M + H]+.
+
1
1
ESI-HRMS: m/z [M + H] calcd for C14
03.1434.
H19O: 203.1430; found:
ported. )
2
1
H NMR (300 MHz, CDCl ): d = 1.30 (d, J = 7.2 Hz, 3 H), 2.20
ddd, J = 16.8, 7.8, 4.6 Hz, 1 H), 2.54 (ddd, J = 16.8, 6.6, 4.6 Hz, 1
3
(
(
trans-1-Methyl-2,3-dihydro-1H-inden-3-yl)(phenyl)methan-
H), 2.91–3.03 (m, 1 H), 5.99 (t, J = 4.6 Hz, 1 H), 7.04 (dd, J = 7.6,
1
7
one (16)
.0 Hz, 1 H), 7.09 (td, J = 7.2, 1.5 Hz, 1 H), 7.15–7.22 (m, 2 H),
.24–7.36 (m, 5 H).
The typical procedure was followed, but 15 (0.222 g, 1.01 mmol)
was used in place of 3. The mixture was stirred for 6 h at 0 °C and
for 18 h at r.t. The residue was purified by flash chromatography
1
3
C NMR (75 MHz, CDCl ): d = 19.8, 31.5, 32.2, 125.7, 126.0,
3
(EtOAc–hexanes, 1:9) giving 16 as a colorless oil; yield: 0.095 g
1
1
26.0, 126.2, 127.0, 127.3, 128.2, 128.2, 128.7, 128.7, 134.3, 139.4,
40.9, 141.6.
(
40%).
–
1
IR (film): 3066, 2958, 1682, 1447, 1218, 755, 699 cm .
9
-Methyl-6,7-dihydro-5H-benzocycloheptene (19)
1
H NMR (300 MHz, CDCl ): d = 1.33 (d, J = 7.2 Hz, 3 H), 2.01
ddd, J = 12.8, 8.8, 7.2 Hz, 1 H), 2.71 (ddd, J = 12.8, 7.2, 4.0 Hz, 1
3
The reaction was performed as described for 12. A mixture of a-
benzosuberone (0.991 g, 6.22 mmol) and MeMgI [prepared from
MeI (2.513 g, 17.7 mmol), Mg (0.407 g, 16.7 mmol), and I (some
crystals) in anhyd Et O (6 mL)] was stirred for 5 h at reflux. The
(
H), 3.50 (sext, J = 7.2 Hz, 1 H), 5.06 (dd, J = 8.8, 4.0 Hz, 1 H),
.05–7.11 (m, 2 H), 7.22–7.25 (m, 2 H), 7.48–7.53 (m, 2 H), 7.57–
7.63 (m, 1 H), 8.03–8.06 (m, 2 H).
2
7
2
1
2
crude product was purified giving 19 as a colorless oil; yield:
.708 g (72%). (The NMR data of 19 were not previously report-
13C NMR (75 MHz, CDCl
): d = 20.5, 38.5, 38.6, 51.1, 123.8,
125.1, 126.4, 127.5, 128.7, 128.7, 128.9, 128.9, 133.0, 136.8, 140.8,
49.4, 200.4.
MS: m/z (%) = 91 (27), 104 (100), 132 (82), 145 (52), 236 (41)
0
3
1
2
ed. )
1
1
H NMR (300 MHz, CDCl ): d = 1.81 (q, J = 7.2 Hz, 2 H), 2.02–
3
+
[
M ].
2
.11 (m, 2 H), 2.09 (s, 3 H), 2.56 (t, J = 6.9 Hz, 2 H), 5.96 (tq,
+
J = 7.2, 1.5 Hz, 1 H), 7.08–7.29 (m, 4 H).
ESI-HRMS: m/z [M + H] calcd for C17H17O: 237.1274; found:
1
3
237.1271.
C NMR (75 MHz, CDCl ): d = 22.6, 24.9, 32.6, 34.5, 125.9,
3
1
26.1, 126.4, 126.5, 128.8, 136.8, 140.9, 141.9.
2
,3-Dihydro-1H-indene-1-carbaldehyde (18)
The typical procedure was followed, but 17 (0.132 g, 1.01 mmol)
was used in place of 3. Evaporation of the solvent afforded the crude
aldehyde 18 as a light yellow oil; yield: 0.144 g (97%).
Oxidation of 4-Methyl-1,2-dihydronaphthalene (3); Typical
Procedure for TTN Reactions
To a stirred soln of 3 (0.144 g, 1.00 mmol) and 3 Å MS (0.072 g, 0.5
1
6
g/g of substrate) in MeCN (5.0 mL) under N was added TTN·3H O
2
2
1
-(1,2,3,4-Tetrahydro-1-naphthyl)ethanone (20)
(0.463 g, 1.10 mmol) at 0 °C. The reagent promptly dissolved. The
The typical procedure was followed, but 19 (0.158 g, 1.00 mmol)
was used in place of 3. The mixture was stirred for 30 min. The res-
idue was purified by flash chromatography (EtOAc–hexanes, 1:9)
mixture was stirred for 10 min and abundant precipitation was ob-
served. The resulting mixture was filtered through a silica gel pad
(
200–400 mesh, ca. 10 cm, CH Cl ). The filtrate was washed with
2 2
Synthesis 2009, No. 3, 385–388 © Thieme Stuttgart · New York

3
88
H. M. C. Ferraz et al.
PAPER
giving 2016 and 21, both as colorless oils; yield (20): 0.132 g (76%);
yield (21): 0.009 g (4%).
(2) (a) Ferraz, H. M. C.; Silva, L. F., Jr.; Vieira, T. O.
Tetrahedron 2001, 57, 1709. (b) Silva, L. F., Jr.; Sousa, R.
M. F.; Ferraz, H. M. C.; Aguilar, A. M. J. Braz. Chem. Soc.
2005, 16, 1160. (c) Ferraz, H. M. C.; Aguilar, A. M.; Silva,
L. F., Jr. Tetrahedron 2003, 59, 5817. (d) Ferraz, H. M. C.;
Aguilar, A. M.; Silva, L. F., Jr. Synthesis 2003, 1031.
(3) Kaye, A.; Neidle, S.; Reese, C. B. Tetrahedron Lett. 1988,
29, 1841.
Compound 21
1
H NMR (300 MHz, CDCl ): d = 1.50–1.65 (m, 1 H), 1.83 (s, 3 H),
3
2
2
7
.07–2.18 (m, 1 H), 2.34–2.43 (m, 1 H), 2.48–2.62 (m, 1 H), 2.82–
.89 (m, 1 H), 2.99–3.08 (m, 1 H), 4.70 (dd, J = 12.3, 3.3 Hz, 1 H),
.11 (dd, J = 7.5, 1.2 Hz, 1 H), 7.21 (td, J = 7.5, 1.5 Hz, 1 H), 7.29
(
1
td, J = 7.5, 1.2 Hz, 1 H), 7.81 (dd, J = 7.5, 1.5 Hz, 1 H).
(4) (a) Harders, J.; Garming, A.; Jung, A.; Kaiser, V.;
Monenschein, H.; Ries, M.; Rose, L.; Schöning, K.-U.;
Weber, T.; Kirschning, A. Liebigs Ann. 1997, 2125.
3
C NMR (75 MHz, CDCl ): d = 22.5, 25.7, 32.1, 36.0, 75.7, 94.0,
3
1
24.9, 127.2, 128.2, 131.4, 138.1, 143.3.
(
b) Silva, L. F., Jr.; Siqueira, F. A.; Pedrozo, E. C.; Vieira, F.
+
MS: m/z (%) = 43 (100), 131 (34), 145 (55), 191 (1) [M – NO ].
2
Y. M.; Doriguetto, A. C. Org. Lett. 2007, 9, 1433.
+
(5) (a) Wiberg, K. B.; Koch, W. Tetrahedron Lett. 1966, 1779.
ESI-HRMS: m/z [M + Na] calcd for C H NO Na: 260.0893;
found: 260.0889.
1
2
15
4
(
b) McKillop, A.; Hunt, J. D.; Taylor, E. C. J. Org. Chem.
972, 37, 3381.
6) Ranu, B. C.; Jana, U. J. Org. Chem. 1998, 63, 8212.
(7) (a) Ferraz, H. M. C.; Silva, L. F., Jr. Tetrahedron Lett. 1997,
1
(
Acknowledgment
38, 1899. (b) Ferraz, H. M. C.; Silva, L. F., Jr. J. Org. Chem.
The authors wish to thank FAPESP and CNPq for financial support.
Dr. F. A. Siqueira is acknowledged for some analysis.
1
998, 63, 1716.
(
(
8) For an example in total synthesis, see: Rigby, J. H.; Kirova-
Snover, M. Tetrahedron Lett. 1997, 38, 8153.
9) Freppel, C.; Favier, R.; Richer, J.-C.; Zador, M. Can. J.
Chem. 1971, 49, 2586.
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(
1) For a review, see: (a) Ferraz, H. M. C.; Aguilar, A. M.;
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735. (e) Minatti, A.; Zheng, X.; Buchwald, S. L. J. Org.
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Synthesis 2009, No. 3, 385–388 © Thieme Stuttgart · New York