Synthesis of polyfunctionalized quinolines via the sequence of propargyl-allenyl isomerization and aza-electrocyclization

Article abstract of DOI:10.1021/jo3018186

Quinoline derivatives are important heterocyclic compounds because of their natural occurrence and applications in pharmaceutical fields. In this paper, a sequence of propargyl-allenyl isomerization and aza-electrocyclization for the synthesis of polyfunctionalized quinolines are described.

Full text of DOI:10.1021/jo3018186

Note
pubs.acs.org/joc
Synthesis of Polyfunctionalized Quinolines via the Sequence of
Propargyl−Allenyl Isomerization and Aza-electrocyclization
Hongwei Zhou,* Le Liu, and Shimin Xu
Department of Chemistry, Zhejiang University (Campus Xixi), Hangzhou 310007, PR China
S
* Supporting Information
ABSTRACT: Quinoline derivatives are important heterocyclic com-
pounds because of their natural occurrence and applications in
pharmaceutical fields. In this paper, a sequence of propargyl−allenyl
isomerization and aza-electrocyclization for the synthesis of polyfunction-
alized quinolines are described.
compounds,5 and the in situ propargyl−allenyl isomerization,
uinoline derivatives, due to their natural occurrence1
2−4
Q and applications in pharmaceutical fields,
such as
which means the preparation of stable and readily accessible
propargyl substrates instead of active and complicated allenes,
has been a useful and efficient method attracting much
attention by organic chemists.6
antimalarial,2 antitumor,3 and antibacterial4 activities, may be
one of the most important heterocyclic compounds. Many
famous molecules in the quinoline family, especially for the 4-
substituted quinoline amine derivatives, for example, quinine,
mefloquine, chloroquine, and amodiaquine (Figure 1), occupy
a prominent place in medicinal chemistry.
During our research on the in situ propargyl−allenyl
isomerization,7 we developed a 6π-electrocyclization protocol
to construct the skeleton of a benzene ring.7a,b Based on the
understanding of propargyl−allenyl isomerization and electro-
cyclization, it might be reasonably envisioned that the aza-
electrocyclization of propargyl phenyl imines could undergo
cycloaddition to give quinolines (Scheme 1).
Scheme 1
On the basis of this proposal, we chose N-(4-phenyl-4-
(phenylimino)but-2-yn-1-yl)-N-(p-tolyl)acetamide (1) as the
starting material, which could be prepared via the Sonogashira
coupling of N-phenylbenzimidoyl chloride with N-(prop-2-yn-
1-yl)-N-(p-tolyl)acetamide.8 We initiated our study by testing
the reaction of 1 in the presence of various bases and examining
the solvent effects. DBU (1, 8-diazabicyclo[5.4.0]undec-7-ene)
and DBN (1,5-diazabicyclo[4.3.0]non-5-ene) could trigger the
expected reaction and give N-((2-phenylquinolin-4-yl)methyl)-
N-(p-tolyl)acetamide (2a) as the product (entries 6 and 7,
Table 1). Further screening showed that acetonitrile was a
suitable solvent (entry 7, Table 1). Interestingly, 0.3 equiv of
DBU could offer better results than stoichiometric base, and 2a
was obtained in 65% yield (entry 19, Table 1).
Figure 1. 4-Substituted quinoline amines.
Generally, there are only three ways to prepare quinolines:
direct functionalization to quinoline, construction of a new
pyridine ring from a benzenoid aromatic compound, or
construction of a new benzene ring from a pyridine. Direct
functionalization to quinoline, due to the effect of the
substituent(s) and the difference of the pyridine ring with
benzene ring, might encounter difficulty in some cases.
Considering the much higher availability of benzenoid aromatic
compounds than pyridine derivatives, construction of a new
pyridine ring from a benzenoid aromatic compound may be an
attractive protocol to access quinolines.
Allene-promoted cyclization reactions, in which the allene
moiety could enhance the reaction possibility compared with
that of a normal olefin, offer a facile route to cyclic
Received: August 25, 2012
Published: September 24, 2012
© 2012 American Chemical Society
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The Journal of Organic Chemistry
Note
Table 1. Examination of Base and Solvent Effects
Table 2. Aza-electrocyclization via Propargyl−Allenyl
a
Isomerization
entry
base
solvent
yield of 2a (%)
1
2
Et3N (3 equiv)
K2CO3 (1 equiv)
Cs2CO3 (1 equiv)
EtONa (1 equiv)
t-BuOK (1 equiv)
DBN (1 equiv)
DBU (1 equiv)
DBU (1 equiv)
DBU (1 equiv)
DBU (1 equiv)
DBU (1 equiv)
DBU (1 equiv)
DBU (1 equiv)
DBU (1 equiv)
DBU (1 equiv)
DBU (0.1 equiv)
DBU (0.15 equiv)
DBU (0.2 equiv)
DBU (0.3 equiv)
DBU (0.5 equiv)
DBU (2 equiv)
MeCN
MeCN
MeCN
EtOH
NR
NR
7
a
3
4
5
13
0
THF
6
MeCN
MeCN
DMF
42
45
35
15
18
25
24
15
32
28
52
59
58
65
56
42
7
8
9
DMSO
acetone
MeOH
Et2O
10
11
12
13
14
15
16
17
18
19
20
21
THF
benzene
toluene
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
a
Starting material was recovered in 45% yield.
With this result in hand, we examined the scope of the
reaction and obtained polyfunctionalized quinolines in
moderate to good yields under mild conditions (Table 2).
The tert-butyl carbamates, shown in Table 2, offered better
yields than the acetamides (entries 3, 6, 8, 10, and 12, Table 2);
on the other hand, tert-butyl carbamates afford a facile way to
amines by the treatment of hydrochloric acid in THF. The
corresponding quinolin-4-ylmethanamine may provide an
access to 1,2-dihydropyrrolo[4,3,2-de]quinoline derivatives,
which are known as an important class applied in
pharmaceutical fields.9 We treated 2l with hydrochloric acid
in THF then heated it at 90 °C with the catalysis of CuI/
proline, and 6-methyl-1,4-diphenyl-1,2-dihydropyrrolo[4,3,2-
de]quinoline (3) was isolated in 65% yield (Scheme 2).
In summary, we have presented here a sequence of
propargyl−allenyl isomerization and aza-electrocyclization for
the facile synthesis of polyfunctionalized quinolines. This
protocol, with the substrates having an amide group for
promoting the reaction, may provide an efficient access to
amines, which offer numerous choices for the functionalization
of the products.
a
All reactions were conducted in acetonitrile (5 mL) under N2
atmosphere on a 0.5 mmol scale.
EXPERIMENTAL SECTION
■
Typical Procedure for the Synthesis of 2a. To a stirred solution
of 1 (182 mg, 0.5 mmol) in 5 mL of dry acetonitrile was added DBU
(22 mg, 0.15 mmol) by syringe at room temperature under N2
atmosphere. Then the reaction mixture was allowed to stir for 6 h,
diluted with 10 mL of water, and extracted with dichloromethane (2 ×
15 mL). The extract was dried with anhydrous Na2SO4. After
evaporation, chromatography on silica gel (hexane/ethyl acetate 5/1)
of the reaction mixture afforded 2a.
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The Journal of Organic Chemistry
Note
129.4, 129.0, 128.8, 127.3, 126.5, 125.0, 124.6, 122.3, 116.3, 81.9, 50.8,
28.1, 26.4; IR (neat, cm−1) 1712, 1681, 1600, 1367; HRMS (TOF)
calcd for C29H28N2O3 452.2100, found 452.2103.
Scheme 2
tert-Butyl (4-chlorophenyl)((2-phenylquinolin-4-yl)methyl)-
1
carbamate (2g): amorphous solid; 158 mg, 71% yield; H NMR
(400 MHz, CDCl3) δ 8.27−8.24 (d, J = 8.4 Hz, 1H), 8.12−8.10 (d, J =
7.6 Hz, 2H), 8.02−8.00 (d, J = 7.6 Hz, 1H), 7.76−7.74 (t, J = 8.4 Hz,
2H), 7.57−7.48 (m, 4H), 7.28−7.23 (t, J = 17.2 Hz, 2H), 7.17 (s, 2H),
5.38 (s, 2H), 1.46 (s, 9H), 13C NMR (100 MHz, CDCl3) δ 156.9,
154.2, 148.3 139.4 130.5, 129.6, 129.4, 128.8, 127.4, 127.1,126.5,
125.1, 122.6, 81.494, 51.0, 28.1; IR (neat, cm−1) 1697, 1602, 1493,
1367, 1318; HRMS (TOF) calcd for C27H25ClN2O2 444.1605, found
444.1607.
tert-Butyl ((2-tert-Butylquinolin-4-yl)methyl)(4-
chlorophenyl)carbamate (2h): gum; 187 mg, 88% yield; 1H
NMR (400 MHz, CDCl3) δ 8.12−8.10 (d, J = 8.8 Hz, 1H), 7.97−
7.95 (d, J = 8 Hz, H), 7.70−7.66 (t, J = 15.2 Hz, 1H), 7.53−7.49 (t, J =
14.8 Hz, 1H), 7.32 (s, 1H), 7.22−7.20 (d, J = 8.8 Hz, 2H), 7.09 (s,
2H), 5.29 (s, 2H), 1.44 (s, 9H), 1.41 (s, 9H); 13C NMR (100 MHz,
CDCl3) δ168.7, 154.1, 147.5, 142.3, 140.7, 132.2, 132.1, 131.4, 130.1,
128.9, 128.7, 128.5, 128.4, 127.3, 125.8, 124.4, 122.3, 116.7, 81.3, 50.9,
38.0, 29.9, 28.1; IR (neat, cm−1) 1696, 1560, 1493, 1366, 1321; HRMS
(TOF) calcd for C25H29ClN2O2 424.1918, found 424.1916.
N-((2-Phenylquinolin-4-yl)methyl)-N-(p-tolyl)acetamide (2a):
yellow solid; mp = 52 − 54 °C; 119 mg, 65% yield; H NMR (400
1
MHz, CDCl3) δ 8.18−8.16 (d, J = 8.4 Hz, 1H), 8.11−8.09 (d, J = 8.4
Hz, 1H), 8.01−7.99 (d, J = 7.2 Hz, 2H), 7.73−7.70 (t, J = 15.6 Hz,
1H), 7.55−7.38 (m, 5H), 7.04−7.01 (d, J = 7.6 Hz, 2H), 6.82−6.80
(d, J = 8.4 Hz, 2H), 5.42 (s, 2H), 2.28 (s, 3H), 1.95 (s, 3H); 13C NMR
(100 MHz, CDCl3) δ 136.7, 135.0, 134.1, 132.3, 130.8, 129.1, 128.8,
128.7, 127.6, 127.1, 126.9, 126.1, 125.5, 38.2, 19.9; IR (neat, cm−1)
2924, 1856, 1601, 1551, 1511, 1388; HRMS (TOF) calcd for
C25H22N2O 366.1732, found 366.1734.
N-((6-Methyl-2-phenylquinolin-4-yl)methyl)-N-(p-tolyl)-
acetamide (2b): amorphous solid; 131 mg, 69% yield; 1H NMR (400
MHz, CDCl3) δ 8.09−8.07 (d, J = 8.4 Hz, 1H), 8.02−8.00 (d, J = 8.0
Hz, 2H), 7.80 (s, 1H), 7.57−7.44 (m, 5H), 7.09−7.07 (d, J = 7.6 Hz,
2H), 6.88−6.86 (d, J = 7.6 Hz, 2H), 5.40 (s, 2H), 2.53 (s, 3H), 2.30 (s,
3H), 1.98 (s, 3H); 13C NMR (100 MHz, CDCl3) δ170.5, 155.8, 146.8,
142.3, 139.5, 138.1, 136.3, 131.6, 130.1, 129.8, 129.0, 128.6, 127.7,
127.3, 125.6, 122.5, 119.6, 49.6, 22.7, 21.9, 20.9; IR (neat, cm−1) 1655,
1509, 1444; HRMS (TOF) calcd for C26H24N2O 380.1889, found
380.1890.
tert-Butyl ((2-tert-Butyl-6-methoxyquinolin-4-yl)methyl)(4-
chlorophenyl)carbamate (2c): gum; 197 mg, 87% yield; 1H
NMR (400 MHz, CDCl3) δ 8.24−8.22 (d, J = 8.4 Hz, 1H), 8.15−
8.13 (d, J = 8.0 Hz, 2H), 7.77−7.72 (t, J = 15.6 Hz, 1H), 7.66 (s, 1H),
7.57−7.48 (m, 4H), 7.37−7.24 (m, 6H), 4.99 (s, 1H), 4.93 (s,1H),
4.61 (s, 1H), 4.44 (s, 1H), 1.58−1.48 (d, J = 36.8 Hz, 9H); 13C NMR
(100 MHz, CDCl3) δ 166.1, 157.4, 154.2, 143.4, 140.7, 140.3, 132.2,
132.1, 131.6, 131.4, 128.7, 128.5, 128.4, 127.8, 125.4, 121.2, 101.0,
81.1, 55.4, 51.1, 37.6, 29.9, 28.1; IR (neat, cm−1) 1698, 1600, 1478,
1454, 1365; HRMS (TOF) calcd for C26H31ClN2O3 454.2023, found
454.2024.
tert-Butyl ((6-bromo-2-phenylquinolin-4-yl)methyl)(4-
chlorophenyl)carbamate (2i): yellow solid; mp = 50−53 °C; 170
1
mg, 65% yield; H NMR (400 MHz, CDCl3) δ 8.18 (s, 1H), 8.08−
8.06 (t, J = 11.2 Hz, 3H), 7.81−7.78 (m, 1H), 7.70 (s, 1H), 7.53−7.47
(m, 3H), 7.24−7.22 (d, J = 8.8 Hz, 2H), 7.10−7.09 (d, J = 6.8 Hz,
2H), 5.30 (s, 2H), 1.47 (s, 9H); 13C NMR (100 MHz, CDCl3) δ157.2,
154.1, 146.9, 142.9, 138.9, 133.0, 132.1, 131.8, 129.6, 128.9, 128.8,
127.3, 126.4, 125.4, 120.6, 81.7, 51.0, 28.2; IR (neat, cm−1)1705, 1600,
1492, 1369; HRMS (TOF) calcd for C27H24BrClN2O2 522.0710,
found 522.0715.
tert-Butyl phenyl((2-phenylquinolin-4-yl)methyl)carbamate
1
(2j): gum; 175 mg, 85% yield; H NMR (400 MHz, CDCl3) δ 8.25−
8.23 (d, J = 8.4 Hz, 1H), 8.11−8.10 (d, J = 6.8 Hz, 2H), 8.04−8.01 (d,
J = 8.4 Hz, 1H), 7.78−7.77 (d, J = 2.8 Hz, 1H), 7.77−7.75 (d, J = 8.4
Hz, 1H), 7.56−7.46 (m, 4H), 7.28−7.27 (d, J = 2.4 Hz, 1H), 7.27−
7.24 (d, J = 4.4 Hz, 1H), 7.24 (s,1H), 7.19−7.17 (t, J = 7.2 Hz, 1H),
5.41 (s, 2H), 1.45 (s, 9H); 13C NMR (100 MHz, CDCl3) δ157.0,
154.5, 148.2, 144.2, 142.3, 139.5, 130.4, 129.4, 129.3, 128.7, 127.4,
126.3, 126.0, 125.9, 125.2, 122.6, 120.5, 117.1, 81.1, 58.3, 51.1, 28.1,
18.3; IR (neat, cm−1) 1689, 1600, 1494, 1478, 1407, 1366; HRMS
(TOF) calcd for C27H26N2O2 410.1994, found 410.1987.
tert-Butyl (4-chlorophenyl)((6-methoxy-2-(p-tolyl)quinolin-
4-yl)methyl)carbamate (2d): yellow solid; mp = 48−51 °C; 171
1
tert-Butyl benzyl((2-phenylquinolin-4-yl)methyl)carbamate
(2k): gum; 170 mg, 80% yield; 1H NMR (500 MHz, DMSO) δ
8.00−7.98 (m, 4H), 7.67−7.64 (t, J = 12.0 Hz, 1H), 7.57 (s, 1H),
7.48−7.41 (m, 3H), 7.39−7.37 (d, J = 5.6 Hz, 1H), 7.17−7.16 (m, 4
H), 7.12−7.09 (m, 1H), 4.89 (s, 2H), 4.43 (s, 2H), 1.27 (s, 9H); 13C
NMR (100 MHz, DMSO) δ156.3, 155.7, 148.3, 139.4, 138.7, 130.3,
130.0, 129.9, 129.2, 128.8, 128.1, 127.5, 127.4, 126.8, 125.8, 123.7,
80.2, 51.2, 48.2, 28.5; IR (neat, cm−1)1698, 1600, 1478, 1454, 1365;
HRMS calcd for C28H28N2O2 424.2151, found 424.2150.
tert-Butyl ((5-bromo-8-methyl-2-phenylquinolin-4-yl)-
methyl)(phenyl)carbamate (2l): gum; 213 mg, 85% yield; 1H
NMR (400 MHz, CDCl3) δ 8.28−8.27 (d, J = 7.2 Hz, 2H), 8.13 (s,
1H), 7.74−7.72 (d, J = 7.6 Hz, 1H), 7.56−7.48 (m, 3H), 7.41−7.31
(m, 5H), 7.19−7.16 (t, J = 14 Hz, 1H), 5.97 (s, 2H), 2.87 (s, 3H), 1.46
(s, 9H); 13C NMR (100 MHz, CDCl3) δ154.7, 154.4, 149.2, 145.6,
142.9, 138.7, 132.9, 129.6, 129.5, 128.8, 128.7, 127.2, 125.5, 125.1,
124.8, 116.1, 114.4, 55.2, 28.1, 19.0; IR (neat, cm−1) 1697, 1593, 1493,
1370; HRMS (TOF) calcd for C28H27BrN2O2 502.1256, found
502.1253.
mg, 70% yield; H NMR (400 MHz, CDCl3) δ 8.10−8.08 (d, J = 9.2
Hz, 1H), 7.93−7.91 (d, J = 7.6 Hz, 2H), 7.55 (s, 1H), 7.39−7.37 (d, J
= 9.2 Hz, 1H), 7.30−7.19 (m, 3H), 7.20−7.18 (d, J = 8.4 Hz, 2H),
7.04 (s, 2H), 5.27 (s, 2H), 2.93 (s, 3H), 2.41 (s, 3H), 1.42 (s, 9H); 13C
NMR (100 MHz, CDCl3) δ157.9, 154.3, 154.2, 132.0, 131.7, 129.0,
128.8, 128.7, 127.5, 127.1, 122.2, 101.1, 81.3, 55.5, 51.2, 29.6, 28.1; IR
(neat, cm−1) 1693, 1622, 1493, 1366; HRMS (TOF) calcd for
C29H29ClN2O3 488.1867, found 488.1868.
tert-Butyl (4-chlorophenyl)((6-methyl-2-phenylquinolin-4-
yl)methyl)carbamate (2e): gum; 183 mg, 80% yield; 1H NMR
(500 MHz, CDCl3) δ 8.11−8.09 (d, J = 8.0 Hz, 1H), 8.07−8.05 (d, J =
7.2 Hz, 2H), 7.73 (s, 1H), 7.66 (s, 1H), 7.58−7.56 (d, J = 8.4 Hz, 1H),
7.51−7.47 (t, J = 14.8 Hz, 2H), 7.45−7.43 (d, J = 6.8 Hz, 2H), 7.22−
7.20 (d, J = 8.8 Hz, 2H), 7.12 (s, 2H), 5.33 (s, 2H), 2.54 (s, 3H), 1.43
(s, 9H); 13C NMR (100 MHz, CDCl3) δ156.1, 154.3, 140.9, 136.5,
132.1, 131.8, 131.6, 130.2, 129.3, 128.9, 128.8, 127.4, 125.2, 121.8,
81.5, 51.2, 29.7, 28.2, 21.9; IR (neat, cm−1) 1258, 1011, 789; HRMS
(TOF) calcd for C28H27ClN2O2 458.1761, found 458.1763.
tert-Butyl (4-acetylphenyl)((2-phenylquinolin-4-yl)methyl)-
carbamate (2f): yellow solid; mp = 62−65 °C; 208 mg, 92% yield;
1H NMR (400 MHz, CDCl3) δ 8.28−8.26 (d, J = 8.4 Hz, 1H), 8.12−
8.10 (d, J = 7.2 Hz, 2H), 8.02−8.00 (d, J = 8.4 Hz, 2H), 7.91−7.89 (d,
J = 8.8 Hz, 2H), 7.80−7.76 (t, J = 16.0 Hz, 2H), 7.61−7.58 (t, J = 14.8
Hz, 1H), 7.54−7.46 (m, 3H), 7.40−7.38 (d, J = 8.4 Hz, 2H), 5.48 (s,
2H), 2.56 (s, 3H), 1.47 (s, 9H); 13C NMR (100 MHz, CDCl3) δ
196.8, 156.9, 153.8, 148.3, 146.7, 143.6, 139.3, 134.0, 130.1, 129.6,
6-Methyl-1,4-diphenyl-1,2-dihydropyrrolo[4,3,2-de]-
quinoline (3). To a stirred solution of 2l (202 mg, 0.5 mmol) in 5 mL
of THF was added 0.5 mL of concentrated hydrochloric acid (12 M)
at room temperature. After 12 h, the reaction mixture was diluted with
10 mL of NaOH (5%) and extracted with ethyl ether (3 × 30 mL).
The extract was washed with water and dried over Na2SO4. After
evaporation, the rescue was charged in a resealable Schlenk tube, and
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The Journal of Organic Chemistry
Note
DMF (4 mL), CuI (14 mg, 0.073 mmol), Cs2CO3 (326 mg, 1.0
mmol), L-(−)-proline(17 mg, 0.15 mmol) were added under nitrogen.
The reaction mixture was stirred at 90 °C for 12 h and filtered through
a plug silica gel (1 × 0.5 cm) eluting with ethyl acetate (50 mL). The
filtrate was concentrated, and the residue was purified by column
chromatography on silica gel (hexane/ethyl acetate 10/1) to get 3 as a
3674. (c) Zhou, H.; Zhu, D.; Xie, Y.; Huang, H.; Wang, K. J. Org.
Chem. 2010, 75, 2706. (d) Zhou, H.; Xie, Y.; Ren, L.; Su, R. Org. Lett.
2010, 12, 356. (e) Zhou, H.; Xie, Y.; Ren, L.; Wang, K. Adv. Synth.
Catal. 2009, 351, 1289.
(8) Ukhin, L. Y.; Orlova, Z. I.; Tokarskaya, O. A. Zh. Org. Khim.
1987, 23, 2473.
(9) (a) Reddy, P. V. N.; Jensen, K. C.; Mesecar, A. D.; Fanwick, P. E.;
Cushman, M. J. Med. Chem. 2012, 55, 367. (b) Zurwerra, D.;
Wullschleger, C. W.; Altmann, K. H. Angew. Chem., Int. Ed. 2010, 49,
6936.
1
yellow solid: mp = 76−78 °C; 104 mg, 65% yield; H′ NMR (400
MHz, CDCl3) δ 8.18−8.16 (d, J = 8.0 Hz, 2H), 7.96 (s, 1H), 7.83 (s,
1H), 7.54 (s, 1H), 7.49−7.47 (m, 3H), 7.26 (s, 1H), 7.22−7.18 (t, J =
15.2 Hz, 2H), 6.79−6.78 (t, J = 14.4 Hz, 1H), 6.66−6.64 (d, J = 8.0
Hz, 2H), 4.74 (s, 2H), 2.89 (s, 3H); 13C NMR (100 MHz,
CDCl3)155.2, 147.7, 144.8, 139.7, 138.4, 129.5. 129.3, 129.2, 128.6,
127.4, 126.0, 125.3, 120.4, 117.9, 116.5, 112.8, 45.6, 18.4; IR (neat,
cm−1) 1600, 1559, 1550, 1316; HRMS (TOF) calcd for C23H18N2
322.1470, found 322.1472.
ASSOCIATED CONTENT
* Supporting Information
■
S
Proton and carbon NMRspectra of products and experimental
procedures for the synthesis of the substrates. This material is
available free of charge via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*E-mail: zhouhw@zju.edu.cn.
■
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
Financial support was received from the Natural Science
Foundation of China (No. 20972134).
■
DEDICATION
Dedicated to the memory of Prof. Xian Huang.
■
REFERENCES
■
(1) (a) Leue, S.; Miao, W.; Kanazawa, A.; Genisson, Y.; Garcon, S.;
Greene, A. E. J. Chem. Soc., Perkin. Trans. 1 2001, 2903. (b) Comins,
D. L.; Nolan, J. M. Org. Lett. 2001, 3, 1611. (c) Rigby, J. H.; Danca, D.
M. Tetrahedron Lett. 1997, 38, 4969.
(2) (a) Samosorn, S.; Bremner, J. B.; Ball, A.; Lewis, K. Bioorg. Med.
Chem. 2006, 14, 857. (b) Foley, M.; Tilley, L. Pharmacol. Ther. 1998,
79, 55.
(3) (a) Myers, A. G.; Tom, N. J.; Fraley, M. E.; Cohen, S. B.; Madar,
D. J. J. Am. Chem. Soc. 1997, 119, 6072. (b) Comins, D. L.; Hong, H.;
Saha, J. K.; Jianhua, G. J. Org. Chem. 1994, 59, 5120. (c) Shen, W.;
Coburn, C. A.; Bornmann, W. G.; Danishefsky, S. J. J. Org. Chem.
1993, 58, 611.
(4) Yearick, K.; Ekoue-Kovi, K.; Iwaniuk, D. P.; Natarajan, J. K.;
Alumasa, J.; DeDios, A. C.; Roepe, P. D.; Wolf, C. J. Med. Chem. 1995,
2008, 51.
(5) (a) Nakamura, I.; Zhang, D.; Terada, M. J. Am. Chem. Soc. 2010,
132, 7884. (b) Cabaleiro-Lago, E. M.; Rodriguez-Otero, J.; Garcia-
Lopez, R. M.; Pena-Gallego, A.; Hermida-Ramon, J. M. Chem.Eur. J.
2005, 11, 5966. (c) Wang, F.; Tong, X.; Cheng, J.; Zhang, Z. Chem.
Eur. J. 2004, 10, 5338. (d) Rodriguez-Otero, J.; Cabaleiro-Lago, E. M.
Angew. Chem., Int. Ed. 2002, 41, 1147. (e) Myers, A. G.; Dragovicb, P.
S.; Kuo, E. Y. J. Am. Chem. Soc. 1992, 114, 9369. (f) Tarasova, O. A.;
Nedolya, N. A.; Brandsmab, L.; Albanov, A. I. Tetrahedron Lett. 2004,
45, 5881. (g) Brandsma, L.; Nedolya, N. A.; Verkruijsse, H. D.; Owen,
N. L.; Li, D.; Trofimov, B. A. Tetrahedron Lett. 1997, 47, 6905.
(6) For a review for the synthetic application of propargyl-allenyl
isomerization, see: Xing, Y.; Wei, Y.; Zhou, H. Curr. Org. Chem 2012,
16, 1594.
(7) (a) Zhou, H.; Xing, Y.; Yao, J.; Lu, Y. J. Org. Chem. 2011, 76,
4582. (b) Zhou, H.; Xing, Y.; Yao, J.; Chen, J. Org. Lett. 2010, 12,
9421
dx.doi.org/10.1021/jo3018186 | J. Org. Chem. 2012, 77, 9418−9421