Rhodium-catalyzed synthesis of isoquinolines and indenes from benzylidenehydrazones and internal alkynes

Article abstract of DOI:10.1021/jo402497v

A new route is presented for the selective assembly of isoquinolines and indenes by rhodium-catalyzed tandem cyclization of benzylidenehydrazones with internal alkynes. This method involves the selective cleavage of the N-N bond and the C=N bonds and is dependent on the substituents of the benzylidenehydrazone.

Full text of DOI:10.1021/jo402497v

Article
pubs.acs.org/joc
Rhodium-Catalyzed Synthesis of Isoquinolines and Indenes from
Benzylidenehydrazones and Internal Alkynes
Xiao-Cheng Huang,†,‡ Xu-Heng Yang,† Ren-Jie Song,† and Jin-Heng Li*,†
†State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University,
Changsha 410082, China
‡Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research, Hunan Normal University, Changsha 410081,
China
S
* Supporting Information
ABSTRACT: A new route is presented for the selective
assembly of isoquinolines and indenes by rhodium-catalyzed
tandem cyclization of benzylidenehydrazones with internal
alkynes. This method involves the selective cleavage of the N−
N bond and the CN bonds and is dependent on the
substituents of the benzylidenehydrazone.
desirable to develop new transition-metal-catalyzed strategies
involving intermolecular processes to expand the applications
of N-aziridinylimines in organic synthesis.
INTRODUCTION
■
N-Aziridinylimines have emerged as an important class of
synthetic building blocks in organic synthesis since Eschen-
moser first reported the thermal fragmentation of N-
aziridinylimines from α,β-epoxy ketones in 1967.1 Generally,
labile N-aziridinylimines can be readily converted into different
reactive intermediates, such as diazoalkane, carbene, and vinyl
anion intermediates, by the use of different reaction conditions
(heat, light, strong bases and/or transition metals; Scheme 1a)
In light of the above findings and the desire to expand the
applications of N-aziridinylimines,1−4 we investigated the
reaction of benzylidenehydrazones with alkynes.5 After a series
of trials, we found that benzylidenehydrazones can undergo an
oxidative tandem reaction with alkynes using the
[(RhCp*Cl2)2]/AgNO3/Cu(OAc)2 catalytic system and that
the chemoselectivity is dependent on the substitution at the 1-
position of the benzylidenehydrazone (Scheme 1b): isoquino-
lines are selectively assembled via cleavage of the N−N and
C(sp2)−H bonds with benzylidenehydrazones bearing two
substituents at the 1-position, whereas indenes are formed from
benzylidenehydrazones with two free N−H bonds through
cleavage of the CN and C(sp2)−H bonds. Herein we report
the Rh(III)-catalyzed oxidative tandem reaction between
benzylidenehydrazones and internal alkynes to give isoquino-
lines and indenes. This reaction is catalyzed by a catalytic
amount of [(RhCp*Cl2)2] combined with a catalytic amount of
AgNO3 and involves the use of Cu(OAc)2 as a promoter
(Scheme 1b).6−8 Notably, the products, isoquinolines and
indenes, are ubiquitous structural components of multitudinous
natural products and biomolecules.9,10
Scheme 1. Utilizations of N-Aziridinylimines
RESULTS AND DISCUSSION
■
and can be used as radical acceptors.1−4 Despite impressive
progress in this field, N-aziridinylimines often have poor
selectivity, and stabilizing groups (often carbonyl groups) are
required. For nonstabilized intermediates of N-aziridinylimines,
transition metals are necessary to stabilize them in situ by
generating nonstabilized metallocarbenoids, thereby introduc-
ing new functional groups on the molecules and leading to new
functionalized complex compounds. However, to our knowl-
edge, these transition-metal-catalyzed transforms are quite rare
and limited to the intramolecular manner.4 Thus, it is highly
Our initial investigation was performed with 1,2-diphenyle-
thyne (1a) and N-(1-phenylethylidene)aziridinylimine (2a) in
the presence of a Rh catalyst (Table 1).4 In the presence of 5
mol % [(RhCp*Cl2)2], a trace amount of isoquinoline 3aa was
observed by GC−MS analysis (entry 1). The yield of 3aa
markedly increased to 72% with the addition of 1 equiv of
Cu(OAc)2 (entry 2). Unfortunately, two other Cu catalysts,
Received: November 11, 2013
Published: January 11, 2014
© 2014 American Chemical Society
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a
Table 1. Screening for Optimal Conditions
entry
[Rh] (mol %)
[Ag]
[Cu]
solvent
yield (%)
1
2
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (2)
RhCl3 (5)


EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
MeOH
t-AmOH
toluene
DMSO
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
trace
72

Cu(OAc)2
CuCl2
3

trace
<5
4

Cu(OTf)2
CuO
5

23
6
AgSbF6
AgNO3
AgOAc
Ag2CO3
Ag2O
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2

72
7
85
8
79
9
84
10
56
b
11
AgNO3
AgNO3
AgNO3
AgNO3
AgNO3
AgNO3
AgNO3
AgNO3
AgNO3
AgNO3
AgNO3
AgNO3
AgNO3
AgNO3

54
12
13
14
15
16
60
trace
trace
0
[RhCp*(NCMe)3]2+ (5)

[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
[(RhCp*Cl2)2] (5)
73
c
17
72
c
18
trace
16
c
19
d
20
48
21
38
e
22

46
f
23

trace
33
g
24

e
25
g

36
26


49
h
27
AgNO3
Cu(OAc)2
82
a
Reaction conditions: 1a (0.2 mmol), 2a (0.3 mmol), [Rh], [Ag] (20 mol %), and [Cu] (1 equiv) in the solvent (2 mL) at reflux under an argon
b
c
d
e
atmosphere for 12 h, unless otherwise noted. At 60 °C for 24 h. At 80 °C. Cu(OAc)2 (20 mol %). CsOAc (1 equiv) instead of Cu(OAc)2.
f
g
h
NaOAc (1 equiv) instead of Cu(OAc)2 (>95% of 2a was recovered). HOAc (1 equiv) instead of Cu(OAc)2. 1a (2 mmol, 0.365 g) and 2a (2.5
mmol, 0.4 g) for 48 h.
CuCl2 and Cu(OTf)2, had no effect on the reaction (entries 3
and 4). When CuO was used, isoquinoline 3aa was obtained in
23% yield (entry 5). It has been reported that Ag salts,
particularly AgSbF6, promote C−H activation/carbocyclization
transformations.6−8 Thus, a series of Ag salts were examined as
catalysts for the reaction (entries 6−10). AgSbF6, the reported
efficient silver salt, had no effect on the reaction (entry 6), and
Ag2O disfavored the reaction (entry 10). However, AgNO3,
AgOAc, and AgCO3 promoted the reaction (entries 7−9). For
example, the addition of 20 mol % AgNO3 increased the yield
from 72% to 85% (entry 2 vs entry 7). Subsequent investigation
of the effect of temperature showed that the reaction at reflux
gave the best results (entries 7 and 11). Notably, the reaction
was successful with 2 mol % Rh, albeit with a moderate yield
(entry 12). However, neither RhCl3 nor [RhCp*(NCMe)3]2+
catalyzed the reaction (entries 13 and 14). It is noteworthy that
the reaction cannot take place in the absence of the Rh catalyst
(entry 15). Among the solvents investigated, the reaction in
EtOH gave the highest yield (entries 7 and 16−19). To
understand the role of Cu(OAc)2, some control experiments
were carried out (entries 20−26). The results showed that the
yield significantly decreased from 85% to 48% in the presence
of 20 mol % Cu(OAc)2 (entry 7 vs entry 20), and to 38%
without Cu catalysts (entry 7 vs entry 21). It has been reported
that the presence of either CsOAc or HOAc promotes some
C−H activation/carbocyclization transformations.6,7 Thus, the
use of CsOAc or HOAc instead of Cu(OAc)2 was tested
(entries 22 and 24): the presence of CsOAc decreased the yield
from 85% to 46% (entry 7 vs entry 22), and the presence of
HOAc decreased the yield from 85% to 33% (entry 7 vs entry
24). However, the presence of NaOAc instead of Cu(OAc)2
resulted in no detectable isoquinoline 3aa (entry 23). The use
of CsOAc or HOAc was also examined without both the Ag salt
and the Cu salt (entries 25 and 26): the Rh-catalyzed
annulation reaction gave isoquinoline 3aa in 36% yield using
CsOAc and in 49% yield using HOAc. These results suggest
that Cu(OAc)2 may serve as both a base and an oxidant to
promote the reaction and that the NN bond of 2a can be
cleaved by bases or acids, such as Cu(OAc)2, CsOAc, and
HOAc. Finally, the reaction of 2 mmol of alkyne 1a with 2.5
mmol of aziridinylimine 2a gave isoquinoline 3aa in good yield
(entry 27).
After the optimal reaction conditions had been determined, a
variety of hydrazones 2 were reacted with 1a to investigate
viable hydrazone substrates (Scheme 2). In the presence of
[(RhCp*Cl2)2], AgNO3, and Cu(OAc)2, 1,1-dialkyl-substituted
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lines 3. Initially, a variety of internal alkynes 1b−e were
investigated for the reaction with aziridinylimine 2a, and they
gave the expected products 3ba−ea under the optimal
conditions. For example, unsymmetric diarylalkyne 1b under-
went the reaction with aziridinylimine 2a, [(RhCp*Cl2)2],
AgNO3, and Cu(OAc)2 to afford a 1:1 mixture of two
regioselective isoquinolines 3ba in 89% total yield. The reaction
of prop-1-ynylbenzene (1c) with aziridinylimine 2a regiospe-
cifically gave only isoquinoline 3ca in moderate yield. Alkyne
1d, which has a free OH group, was also found to be suitable
for producing isoquinoline 3da in 61% yield. The optimal
conditions were compatible with aliphatic alkyne 1e (product
3ea). Therefore, we decided to explore the scope of N-(1-
arylethylidene)hydrazones 2 in the presence of alkyne 1a,
[(RhCp*Cl2)2], AgNO3, and Cu(OAc)2 (products 3ah−at).
Extensive screening revealed that several substituents, including
MeO, Me, Ph, Cl, and Br groups, on the aromatic ring of the N-
(1-arylethylidene) moiety were well-tolerated (products 3ah−
an), and the reactivity order was para > meta > ortho. While o-
MeO-substituted substrate 2h reacted with alkyne 1a to give
isoquinoline 3ah in 75% yield, m- and p-MeO-substituted
substrates 2i and 2j provided isoquinolines 3ai and 3aj in 87%
and 95% yield, respectively. Notably, m-MeO-substituted
substrate 2i gave a mixture of regioselective isomers. Both Cl-
and Br-substituted isoquinolines 3am and 3an were successfully
formed, thereby facilitating possible additional modifications at
the halogenated position. Importantly, this current reaction
could be applied to prepare complex heterocycles 3ao−ar,
which makes this methodology more useful in organic
synthesis. For example, the reaction provides a facile route to
benzo[h]isoquinoline 3ao and 8,9-dihydro-7H-benzo[de]-
quinoline 3ap. Interestingly, both thieno[2,3-c]pyridine 3aq
and furo[2,3-c]pyridine 3ar were also formed in good yields. It
is noteworthy that 1-ethyl- and 1-phenyl-substituted isoquino-
lines 3as and 3at were easily prepared.
Scheme 2. Screening of the Effect of Substitution at the 1-
Position of the Benzylidenehydrazone
hydrazones 2b−e gave isoquinoline 3aa, although their
reactivities were lower than that of aziridinylimine 2a. However,
hydrazone 2f, which has a Ts group at the 1-position, was
unreactive. To our surprise, (1-phenylethylidene)hydrazone
(2g) with two free N−H bonds gave indene 4ag as the major
product (71% yield) together with isoquinoline 3aa as a side
product (10% yield).
As shown in Table 2, we applied the Rh-catalyzed tandem
approach to the synthesis of various functionalized isoquino-
a
Table 2. Rh-Catalyzed Synthesis of Isoquinolines 3
We next turned our attention to the preparation of indenes
from (1-phenylethylidene)hydrazone (2g) and its derivatives
2u−z (Table 3). In the presence of [(RhCp*Cl2)2], AgNO3,
and Cu(OAc)2, hydrazone 2g showed high reactivity with
various alkynes to give indenes 4cg−gg in satisfactory yields.
For example, the reaction of hydrazone 2g with 1-phenyl-
propyne (1c) afforded indene 4cg in good yield, albeit with
only a 5% yield of isoquinoline 3aa. When alkynols 1d and 1f
were used, the corresponding indenes 4dg and 4fg together
with the dehydrated indenes 5dg and 5fg were isolated.8h The
current reaction could be readily used for the synthesis of 1,2,3-
trialkyl-substituted indene 4eg, although isoquinoline 3ea was
also formed. Notably, electron-poor alkyne 1g under the
optimal conditions gave only indene 4gg in moderate yield.
Furthermore, other hydrazones 2u−z with substituents such as
MeO, Me, Cl, and NO2 groups on the aromatic ring
successfully reacted with alkyne 1a to provide the correspond-
ing indenes 4au−az in moderate to good yields.
Table 1 shows that isoquinoline 3aa was obtained in 72%
yield without Ag salt (entry 2) and that the yield increased to
85% in the presence of AgNO3 (entry 7), suggesting that
AgNO3 only activates [(RhCp*Cl2)2]. The reaction of alkyne
1a with aziridinylimine 2a in the presence of [(RhCp*Cl2)2],
AgNO3, and Cu(OAc)2 was monitored in situ by GC−MS
analysis, which showed that some byproducts were formed,
including bis(1-phenylethylidene)hydrazone (6aa) and aceto-
phenone (7aa) (eq 1 in Scheme 3). Further experiments
showed that the reaction of 0.15 mmol of hydrazone 6aa with
a
Reaction conditions: 1 (0.2 mmol), 2 (0.3 mmol), [(RhCp*Cl2)2] (5
mol %), AgNO3 (20 mol %), and Cu(OAc)2 (1 equiv) in EtOH (2
mL) at reflux for 12 h.
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a
Table 3. Rh-Catalyzed Synthesis of Indenes 4 and 5
Scheme 4. Possible Mechanisms
of the CN bond in intermediate B, leading to intermediate
D. Finally, N−N bond cleavage of either intermediate C or
intermediate D takes place to yield the corresponding product
3aa or 4ag with the aid of Cu(OAc)2.
a
Reaction conditions: 1 (0.2 mmol), 2 (0.3 mmol), [(RhCp*Cl2)2] (5
mol %), AgNO3 (20 mol %), and Cu(OAc)2 (1 equiv) in EtOH (2
b
mL) at reflux for 12 h. Isoquinoline 3ca was isolated in 5% yield.
c
d
Isoquinoline 3ea was isolated in 48% yield. Isoquinoline 3ah was
e
isolated in 46% yield. Isoquinoline 3aj was isolated in 22% yield.
CONCLUSIONS
f
g
■
Isoquinoline 3ak was isolated in 22% yield. Isoquinoline 3am was
h
In summary, we have illustrated a novel Rh-catalyzed tandem
reaction for the selective synthesis of isoquinolines and indenes.
This method is realized through selective cleavage of the N−N
bond or the CN bond followed by sequential C−H
activation and cyclization with internal alkynes. The mechanism
has been discussed according to kinetic isotope effect
experiments and in situ HRMS analysis.
isolated in 15% yield. Isoquinoline 3as was isolated in 17% yield.
Scheme 3. Control Experiments
EXPERIMENTAL SECTION
■
1
General Considerations. The H and 13C NMR spectra were
recorded in CDCl3 solvent on an NMR spectrometer using TMS as an
internal standard. LRMS was performed on a GC−MS instrument and
HRMS was measured on an electrospray ionization (ESI) apparatus
using time-of-flight (TOF) mass spectrometry. Melting points are
uncorrected.
Preparation of Benzylidenehydrazones 2. All of the
benzylidenehydrazones 2 were synthesized according to known
methods.3
0.2 mmol of alkyne 1a gave isoquinoline 3aa in 72% yield (eq
2) but that ketone 7aa was unreactive (eq 3). Compared with
the yield of the reaction under the optimized reaction
conditions (entry 7 in Table 1), these results indicate that
hydrazone 6aa might be involved in this process but is probably
not an intermediate in the main pathway of the reaction.
Consequently, mechanisms for the selective syntheses of
isoquinolines and indenes are proposed on the basis of the
present results and previously reported mechanisms4−8
(Scheme 4). Initially, [(RhCp*Cl2)2] is easily converted to
the active RhIIICp* species by AgNO3.6−8 Subsequently,
RhIIICp* treated with benzylidenehydrazone 2 gives a new
Rh intermediate A via cleavage of the C(sp2)−H bond and
formation of the C−Rh and Rh−N bonds, which is supported
by the results of in situ HRMS analysis (see Figure S1 in the
Supporting Information). Insertion of alkyne 1a into the
C(sp2)−Rh bond of Rh intermediate A offers intermediate B,
which can follow one of two pathways depending on the
substitution of benzylidenehydrazone 2: either (1) direct
reductive elimination of intermediate B to give intermediate
C and the RhICp* species or (2) addition of the carbon atom
Typical Experimental Procedure for the Rh-Catalyzed
Synthesis of Isoquinolines and Indenes. To a Schlenk tube
were added alkyne 1 (0.2 mmol), benzylidenehydrazone 2 (0.3 mmol),
[(RhCp*Cl2)2] (5 mol %), AgNO3 (20 mol %), Cu(OAc)2 (0.2
mmol), and anhydrous EtOH (2 mL). Then the tube was charged with
argon, and the reaction mixture was stirred under reflux (oil bath
temperature of about 80 °C) for the indicated time until complete
consumption of the starting material was achieved as monitored by
TLC and/or GC−MS analysis. After the reaction was finished, the
reaction mixture was cooled to room temperature, diluted with diethyl
ether (5 mL), and washed with brine (3 × 1 mL). The aqueous phase
was re-extracted with diethyl ether (3 × 2 mL). The combined organic
extracts were dried over Na2SO4 and concentrated in vacuum, and the
resulting residue was purified by silica gel column chromatography
(hexane/ethyl acetate = 20:1) to afford the desired product.
1-Methyl-3,4-diphenylisoquinoline (3aa).7q Yellow solid (50.2 mg,
85% yield), mp 104.8−106.6 °C; 1H NMR (500 MHz, CDCl3) δ 3.07
(s, 3H), 7.15−7.23 (m, 5H), 7.30−7.37 (m, 5H), 7.56−7.58 (m, 2H),
7.64−7.66 (m, 1H), 8.17−8.20 (m, 1H); 13C NMR (125 MHz,
CDCl3) δ 22.7, 125.5, 126.1, 126.2, 126.5, 126.9, 127.1, 127.6, 128.1,
129.1, 129.9, 130.2, 131.4, 135.9, 137.5, 141.0, 149.4, 157.7; LRMS (EI
70 eV) m/z (%) 295 (M+, 52), 294 (100).
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4-(4-Methoxyphenyl)-1-methyl-3-phenylisoquinoline (3ba). Yel-
low solid (28.9 mg, 44.5% yield), mp 152.4−153.8 °C; 1H NMR (500
MHz, CDCl3) δ 3.06 (s, 3H), 3.82 (s, 3H), 6.86−6.89 (m, 2H), 7.12−
7.22 (m, 5H), 7.36−7.40 (m, 2H), 7.55−7.59 (m, 2H), 7.68−7.70 (m,
1H), 8.17−8.19 (m, 1H); 13C NMR (125 MHz, CDCl3) δ 22.7, 55.2,
113.6, 125.5, 126.2 (126.2), 126.4, 126.8, 127.6, 128.8, 129.6, 129.8,
130.2, 132.4, 136.3, 141.1, 149.5, 157.4, 158.6; LRMS (EI 70 eV) m/z
(%) 325 (M+, 69), 324 (100); HRMS (ESI) calcd for C23H19NO [M +
H]+ 326.1539, found 326.1554.
1,6-Dimethyl-3,4-diphenylisoquinoline (3ak).7q Yellow solid (56.2
mg, 91% yield), mp 165.4−166.2 °C; 1H NMR (500 MHz, CDCl3) δ
2.41 (s, 3H), 3.03 (s, 3H), 7.13−7.21 (m, 5H), 7.29−7.35 (m, 5H),
7.38−7.40 (m, 2H), 8.06 (d, J = 8.5 Hz, 1H); 13C NMR (125 MHz,
CDCl3) δ 22.1, 22.6, 124.5, 125.0, 125.4, 126.8, 126.9, 127.5, 128.1,
128.6, 128.7, 130.2, 131.4, 136.1, 137.7, 140.1, 141.1, 149.5, 157.3;
LRMS (EI 70 eV) m/z (%) 309 (M+, 57), 308 (100).
1-Methyl-3,4,6-triphenylisoquinoline (3al).7p Yellow solid (67.5
mg, 91% yield), mp 176.5−178.1 °C; 1H NMR (500 MHz, CDCl3) δ
3.08 (s, 3H), 7.16−7.19 (m, 3H), 7.25 (d, J = 8.0 Hz, 2H), 7.30−7.41
(m, 8H), 7.54 (d, J = 8.0 Hz, 2H), 7.81 (d, J = 8.5 Hz, 1H), 7.85 (s,
1H), 8.23 (d, J = 8.5 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ 22.6,
123.9, 125.1, 126.1, 126.9, 127.1, 127.2, 127.4, 127.5, 127.9, 128.2,
128.8, 129.3, 130.2, 131.4, 136.3, 137.4, 140.4, 141.0, 142.4, 149.9,
157.5; LRMS (EI 70 eV) m/z (%) 371 (M+, 63), 370 (100).
6-Chloro-1-methyl-3,4-diphenylisoquinoline (3am).7r Yellow solid
3-(4-Methoxyphenyl)-1-methyl-4-phenylisoquinoline (3ba′).11
1
Yellow solid (28.9 mg, 44.5% yield), mp 161.7−163.6 °C; H NMR
(500 MHz, CDCl3) δ 3.06 (s, 3H), 3.74 (s, 3H), 6.71−6.74 (m, 2H),
7.22−7.24 (m, 2H), 7.31−7.38 (m, 5H), 7.55−7.57 (m, 2H), 7.62−
7.64 (m, 1H), 8.16−8.18 (m, 1H); 13C NMR (125 MHz, CDCl3) δ
22.7, 55.1, 113.1, 125.5, 125.9, 126.1, 126.2 (2C), 127.0, 128.3, 128.6,
129.8, 131.3, 131.5, 133.5, 136.1, 137.8, 148.9, 157.6, 158.6; LRMS (EI
70 eV) m/z (%) 325 (M+, 67), 324 (100); HRMS (EI) calcd for
C23H19NO [M + H]+ 326.1539, found 326.1574.
1
(48.0 mg, 73% yield), mp 175.6−177.4 °C; H NMR (500 MHz,
CDCl3) δ 3.04 (s, 3H), 7.16−7.20 (m, 5H), 7.32−7.36 (m, 5H), 7.50
(d, J = 9.0 Hz, 1H), 7.62 (s, 1H), 8.11 (d, J = 9.0 Hz, 2H); 13C NMR
(125 MHz, CDCl3) δ 22.7, 124.3, 125.0, 127.1, 127.3, 127.4, 127.6,
128.4 (2C), 130.1, 131.2, 136.3, 136.8, 137.0, 140.5, 150.5, 157.6;
LRMS (EI 70 eV) m/z (%) 331 (M+ + 2, 19), 329 (M+, 51), 330 (40),
328 (100).
1,4-Dimethyl-3-phenylisoquinoline (3ca).7q Yellow solid (23.3 mg,
50% yield), mp 88.5−90.9 °C; 1H NMR (500 MHz, CDCl3) δ 2.59 (s,
3H), 2.98 (s, 3H), 7.38 (t, J = 8.0 Hz, 1H), 7.46 (t, J = 7.5 Hz, 2H),
7.56−7.62 (m, 3H), 7.74 (t, J = 7.5 Hz, 1H), 8.05 (d, J = 8.5 Hz, 1H),
8.16 (d, J = 8.0 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ 15.4, 22.5,
122.2, 124.1, 126.0, 126.1, 126.2, 127.4, 128.1, 129.8, 136.2, 141.6,
150.6, 155.9; LRMS (EI 70 eV) m/z (%) 233 (M+, 47), 232 (100).
(1-Methyl-3-phenylisoquinolin-4-yl)methanol (3da).7p Yellow
solid (30.4 mg, 61% yield), mp 151.8−153.6 °C; 1H NMR (500
MHz, CDCl3) δ 5.02 (s, 2H), 7.40−7.43 (m, 1H), 7.47 (t, J = 7.0 Hz,
2H), 7.62−7.66 (m, 3H), 7.79 (t, J = 8.0 Hz, 1H), 8.19 (d, J = 8.5 Hz,
1H), 8.29 (d, J = 8.5 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ 22.7,
59.4, 124.1, 124.4, 126.1, 126.7 (2C), 128.0, 128.2, 129.6, 130.6, 135.7,
140.4, 151.8, 158.6; LRMS (EI 70 eV) m/z (%) 249 (M+, 95), 248
(100).
6-Bromo-1-methyl-3,4-diphenylisoquinoline (3an).7q Yellow solid
1
(60.4 mg, 81% yield), mp 190.2−191.6 °C; H NMR (500 MHz,
CDCl3) δ 3.03 (s, 3H), 7.17−7.20 (m, 5H), 7.33−7.35 (m, 5H), 7.63
(d, J = 9.0 Hz, 1H), 7.80 (s, 1H), 8.02 (d, J = 8.5 Hz, 1H); 13C NMR
(125 MHz, CDCl3) δ 22.6, 124.5, 125.0, 127.1, 127.2, 127.4, 127.6,
128.2, 128.3, 128.4, 129.9, 130.1, 131.2, 136.7, 137.3, 140.5, 150.5,
157.7; LRMS (EI 70 eV) m/z (%) 375 (M+ + 2, 53), 373 (M+, 55),
372 (100), 374 (100).
1-Methyl-3,4-diphenylbenzo[h]isoquinoline (3ao).7q Yellow solid
1
(56.6 mg, 82% yield), mp 140.9−142.8 °C; H NMR (500 MHz,
1-Methyl-3,4-dipropylisoquinoline (3ea).7q Yellow oil (30.9 mg,
68% yield); 1H NMR (500 MHz, CDCl3) δ 1.03−1.10 (m, 6H), 1.63−
1.71 (m, 2H), 1.75−1.83 (m, 2H), 2.89−2.92 (m, 5H), 2.96−2.99 (m,
2H), 7.48 (t, J = 7.5 Hz, 1H), 7.64 (t, J = 7.5 Hz, 1H), 7.95 (d, J = 8.5
Hz, 1H), 8.07 (d, J = 8.5 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ
14.4, 14.6, 22.3, 23.8, 24.2, 29.8, 37.4, 123.5, 125.2, 125.9, 126.0, 126.1,
129.4, 135.4, 151.6, 155.6; LRMS (EI 70 eV) m/z (%) 227 (M+, 53),
226 (41), 212 (80), 198 (100).
CDCl3) δ 3.43 (s, 3H), 7.18−7.25 (m, 5H), 7.32−7.37 (m, 3H), 7.43
(d, J = 8.0 Hz, 2H), 7.54 (d, J = 9.0 Hz, 1H), 7.64 (t, J = 7.5 Hz, 1H),
7.70−7.73 (m, 1H), 7.76 (d, J = 9.0 Hz, 1H), 7.90 (d, J = 8.0 Hz, 1H),
8.89 (d, J = 8.5 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ 30.5, 123.9,
124.2, 126.6, 126.8, 127.1, 127.2, 127.3, 127.6, 128.2, 128.7, 129.6,
130.2, 131.1, 131.6, 132.9, 137.2, 138.0, 140.6, 150.9, 155.4; LRMS (EI
70 eV) m/z (%) 345 (M+, 78), 344 (100).
2,3-Diphenyl-8,9-dihydro-7H-benzo[de]quinoline (3ap).7p Yellow
solid (55.9 mg, 87% yield), mp 158.6−160.8 °C; 1H NMR (500 MHz,
CDCl3) δ 2.21−2.26 (m, 2H), 3.15 (t, J = 6.0 Hz, 2H), 3.35−3.37 (m,
2H), 7.11−7.21 (m, 5H), 7.27−7.36 (m, 6H), 7.42−7.46 (m, 2H); 13C
NMR (125 MHz, CDCl3) δ 23.3, 30.6, 34.7, 123.4, 123.8, 124.6, 126.8,
126.9, 127.5, 128.9, 129.9, 130.2, 131.3, 136.1, 137.7, 138.4, 141.1,
149.3, 159.2; LRMS (EI 70 eV) m/z (%) 321 (M+, 62), 320 (100).
7-Methyl-4,5-diphenylthieno[2,3-c]pyridine (3aq).7p Yellow solid
8-Methoxy-1-methyl-3,4-diphenylisoquinoline (3ah).7p Yellow
solid (48.8 mg, 75% yield), mp 139.4−141.2 °C; 1H NMR (500
MHz, CDCl3) δ 3.21 (s, 3H), 3.99 (s, 3H), 6.88 (d, J = 8.0 Hz, 1H),
7.14−7.23 (m, 6H), 7.28−7.36 (m, 5H), 7.42 (t, J = 8.0 Hz, 1H); 13C
NMR (125 MHz, CDCl3) δ 29.2, 55.5, 105.9, 118.3, 119.0, 126.9,
127.0, 127.5, 128.1, 128.3, 130.0, 130.2, 131.4, 138.2, 138.8, 140.9,
149.5, 157.4, 158.1; LRMS (EI 70 eV) m/z (%) 325 (M+, 70), 324
(100).
1
7-Methoxy-1-methyl-3,4-diphenylisoquinoline (3ai).7p Yellow
solid (40.3 mg, 62% yield), mp 128.2−130.0 °C; 1H NMR (500
MHz, CDCl3) δ 3.03 (s, 3H), 3.40 (s, 3H), 6.95 (d, J = 7.5 Hz, 1H),
7.09−7.17 (m, 8H), 7.21−7.23 (m, 2H), 7.52 (t, J = 8.0 Hz, 1H), 7.79
(d, J = 8.5 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ 23.4, 55.5, 110.0,
118.0, 125.6, 126.4, 127.1, 127.3, 127.7, 130.2, 130.3, 141.4, 151.0,
156.8; LRMS (EI 70 eV) m/z (%) 325 (M+, 84), 324 (100).
5-Methoxy-1-methyl-3,4-diphenylisoquinoline (3ai′).3 Yellow
solid (16.3 mg, 25% yield), mp 146.5−149.0 °C; 1H NMR (500
MHz, CDCl3) δ 3.02 (s, 3H), 3.96 (s, 3H), 7.13−7.24 (m, 6H), 7.29−
7.37 (m, 6H), 7.57 (d, J = 9.0 Hz, 1H); 13C NMR (125 MHz, CDCl3)
δ 22.8, 55.4, 103.4, 122.2, 126.7, 127.0, 127.2, 127.5, 127.9, 128.1,
129.1, 130.2, 131.3 (2C), 137.7, 141.0, 147.6, 155.9, 157.8; LRMS (EI
70 eV) m/z (%) 325 (M+, 76), 324 (100).
(57.2 mg, 95% yield), mp 148.5−149.2 °C; H NMR (500 MHz,
CDCl3) δ 2.90 (s, 3H), 7.17−7.23 (m, 6H), 7.27−7.31 (m, 3H), 7.35
(d, J = 7.5 Hz, 2H), 7.58 (d, J = 5.5 Hz, 1H); 13C NMR (125 MHz,
CDCl3) δ 23.6, 124.2, 127.0, 127.1, 127.7, 128.2 (2C), 130.3, 130.5,
130.9, 134.2, 138.2, 140.4, 145.6, 150.9, 151.3; LRMS (EI 70 eV) m/z
(%) 301 (M+, 56), 300 (100).
7-Methyl-4,5-diphenylfuro[2,3-c]pyridine (3ar).7n Yellow solid
1
(46.2 mg, 81% yield), mp 107.9−108.2 °C; H NMR (500 MHz,
CDCl3) δ 2.85 (s, 3H), 6.72 (s, 1H), 7.19−7.35 (m, 10H), 7.73 (s,
1H); 13C NMR (125 MHz, CDCl3) δ 18.7, 106.4, 126.7, 127.0 (2C),
127.7, 128.3, 130.2, 130.3, 134.2, 137.6, 140.5, 141.3, 147.8, 149.6,
149.9; LRMS (EI 70 eV) m/z (%) 285 (M+, 54), 284 (100).
1-Ethyl-6-methyl-3,4-diphenylisoquinoline (3as). Yellow solid
1
(62.7 mg, 97% yield), mp 138.8−140.7 °C; H NMR (500 MHz,
6-Methoxy-1-methyl-3,4-diphenylisoquinoline (3aj).7q Yellow
solid (61.8 mg, 95% yield), mp 181.0−182.2 °C; 1H NMR (500
MHz, CDCl3) δ 3.02 (s, 3H), 3.72 (s, 3H), 6.91 (s, 1H), 7.15−7.23
(m, 6H), 7.30−7.35 (m, 5H), 8.11 (d, J = 9.0 Hz, 1H); 13C NMR (125
MHz, CDCl3) δ 22.6, 55.2, 104.5, 118.7, 121.9, 126.8, 127.1, 127.4,
127.5, 128.2, 128.6, 130.2, 131.3, 137.9, 138.1, 141.2, 150.1, 157.0,
160.5; LRMS (EI 70 eV) m/z (%) 325 (M+, 63), 324 (100).
CDCl3) δ 1.52 (t, J = 7.5 Hz, 3H), 2.42 (s, 3H), 3.38−3.43 (m, 2H),
7.13−7.23 (m, 5H), 7.32−7.41 (m, 7H), 8.14 (d, J = 9.0 Hz, 1H); 13C
NMR (125 MHz, CDCl3) δ 14.0, 22.0, 28.7, 123.6, 125.0, 125.1, 126.7,
126.9, 127.4, 128.0, 128.1, 128.4, 128.5, 129.1, 130.2, 131.3, 136.8,
137.8, 139.8, 141.2, 149.3, 161.8; LRMS (EI 70 eV) m/z (%) 323 (M+,
59), 322 (100); HRMS (EI) calcd for C24H22N [M + H]+ 324.1747,
found 324.1745.
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Article
1,3,4-Triphenylisoquinoline (3at).12 Yellow solid (63.5 mg, 89%
yield), mp 171.6−173.8 °C; 1H NMR (500 MHz, CDCl3) δ 7.14−7.19
(m, 3H), 7.28−7.30 (m, 2H), 7.33−7.38 (m, 3H), 7.42−7.58 (m, 7H),
7.71 (d, J = 8.5 Hz, 1H), 7.81−7.83 (m, 2H), 8.17 (d, J = 8.0 Hz, 1H);
13C NMR (125 MHz, CDCl3) δ 125.4, 126.0, 126.5, 126.9, 127.2,
127.4, 127.5, 128.2, 128.3 (2C), 128.5, 129.9, 130.0, 130.2, 130.4,
136.9, 137.5, 139.8, 140.8, 149.6, 159.7; LRMS (EI 70 eV) m/z (%)
357 (M+, 63), 356 (100).
CDCl3) δ 2.48 (s, 3H), 3.88 (s, 3H), 4.87 (s, 1H), 6.79 (d, J = 8.0 Hz,
2H), 7.01 (d, J = 7.5 Hz, 2H), 7.05−7.14 (m, 5H), 7.22−7.26 (m,
4H); 13C NMR (125 MHz, CDCl3) δ 14.9, 55.4, 58.2, 109.5, 116.8,
126.3, 126.4, 126.5, 127.9, 128.2, 128.4, 129.2, 133.2, 136.0, 136.6,
140.1, 143.7, 150.4, 154.7; LRMS (EI 70 eV) m/z (%) 313 (26), 312
(M+, 100), 297 (50); HRMS (ESI) calcd for C23H21O [M + H]+
313.1587, found 313.1599.
6-Methoxy-3-methyl-1,2-diphenyl-1H-indene (4av). White solid
(31.2 mg, 50% yield), mp 98.6−100.3 °C; 1H NMR (500 MHz,
CDCl3) δ 2.30 (s, 3H), 3.73 (s, 3H), 4.90 (s, 1H), 6.77 (s, 1H), 6.86
(d, J = 8.0 Hz, 1H), 7.03 (d, J = 8.0 Hz, 2H), 7.08 (t, J = 7.5 Hz, 1H),
7.11−7.15 (m, 3H), 7.22−7.28 (m, 5H); 13C NMR (125 MHz,
CDCl3) δ 12.0, 55.5, 57.7, 110.2, 112.2, 119.6, 126.2, 126.4, 128.1,
128.5, 128.6, 135.2, 136.5, 139.1, 140.2, 143.0, 149.8, 158.4; LRMS (EI
70 eV) m/z (%) 313 (27), 312 (M+, 100), 297 (49); HRMS (EI) calcd
for C23H21O [M + H]+ 313.1587, found 313.1599.
3-Methyl-1,2-diphenyl-1H-indene (4ag).13 White solid (40.0 mg,
71% yield), mp 89.3−90.2 °C; 1H NMR (500 MHz, CDCl3) δ 2.33 (s,
3H), 4.93 (s, 1H), 7.02 (d, J = 8.0 Hz, 2H), 7.07−7.19 (m, 6H), 7.24−
7.33 (m, 5H), 7.39 (d, J = 7.5 Hz, 1H); 13C NMR (125 MHz, CDCl3)
δ 11.9, 57.8, 119.1, 123.6, 125.4, 126.4, 126.5, 126.8, 128.1 (2C),
128.4, 129.0, 135.5, 136.3, 140.0, 145.0, 145.9, 148.0; LRMS (EI 70
eV) m/z (%) 282 (M+, 100), 267 (64).
1,3-Dimethyl-2-phenyl-1H-indene (4cg).14 White solid (33.4 mg,
76% yield), mp 74.2−75.8 °C; 1H NMR (500 MHz, CDCl3) δ 1.19 (d,
J = 7.5 Hz, 3H), 2.24 (s, 3H), 3.85−3.89 (m, 1H), 7.21−7.49 (m, 9H);
13C NMR (125 MHz, CDCl3) δ 11.6, 16.3, 45.7, 119.1, 122.5, 124.9,
126.6 (2C), 128.3, 128.5, 129.0, 133.2, 136.5, 145.8, 146.7, 148.3;
LRMS (EI 70 eV) m/z (%) 220 (M+, 100), 205 (94).
3,6-Dimethyl-1,2-diphenyl-1H-indene (4aw).13 Yellow solid (30.8
mg, 52% yield), mp 167.8−169.6 °C; 1H NMR (500 MHz, CDCl3) δ
2.31 (s, 3H), 2.32 (s, 3H), 4.90 (s, 1H), 7.00−7.04 (m, 3H), 7.07−
7.16 (m, 5H), 7.23−7.29 (m, 5H); 13C NMR (125 MHz, CDCl3) δ
11.9, 21.5, 57.6, 118.9, 124.5, 126.3, 126.4, 127.5, 128.0, 128.2, 128.4,
128.9, 135.2, 135.5, 136.5, 140.3, 143.3, 144.0, 147.3; LRMS (EI 70
eV) m/z (%) 296 (M+, 100), 281 (69).
(3-Methyl-2-phenyl-1H-inden-1-yl)methanol (4dg). Yellow oil
1
(25.5 mg, 54% yield); H NMR (500 MHz, CDCl3) δ 2.24 (s, 3H),
3.63−3.66 (m, 1H), 3.98−4.01 (m, 1H), 4.05−4.06 (m, 1H), 7.23−
7.44 (m, 8H), 7.57 (d, J = 7.0 Hz, 1H); 13C NMR (125 MHz, CDCl3)
δ 11.6, 53.8, 63.4, 119.4, 123.0, 125.1, 127.0, 127.3, 128.5, 128.9, 135.9,
136.1, 141.9, 144.0, 146.8; LRMS (EI 70 eV) m/z (%) 236 (M+, 67),
206 (98), 205 (100); HRMS (ESI) calcd for C17H17O [M + H]+
237.1274, found 237.1286.
6-Chloro-3-methyl-1,2-diphenyl-1H-indene (4ax). Yellow oil (52.5
mg, 83% yield); 1H NMR (500 MHz, CDCl3) δ 2.30 (s, 3H), 4.91 (s,
1H), 7.01 (d, J = 7.5 Hz, 2H), 7.10 (t, J = 7.5 Hz, 1H), 7.13−7.17 (m,
4H), 7.21−7.27 (m, 6H); 13C NMR (125 MHz, CDCl3) δ 11.9, 57.6,
120.0, 124.1, 126.7, 126.8, 127.1, 128.1 (2C), 128.6, 128.9, 131.3,
134.8, 135.9, 139.1, 144.4, 145.4, 149.6; LRMS (EI 70 eV) m/z (%)
318 (M+ + 2, 18), 316 (M+, 59), 281 (100); HRMS (ESI) calcd for
C22H18Cl [M + H]+ 317.1091, found 317.1104.
3-Methyl-1-methylene-2-phenyl-1H-indene (5dg).15 Colorless oil
(5.2 mg, 12% yield); 1H NMR (500 MHz, CDCl3) δ 2.19 (s, 3H), 5.56
(s, 1H), 6.07 (s, 1H), 7.23−7.26 (m, 1H), 7.29 (d, J = 7.0 Hz, 1H),
7.33−7.36 (m, 4H), 7.44 (t, J = 7.5 Hz, 2H), 7.63 (d, J = 7.5 Hz, 1H);
13C NMR (125 MHz, CDCl3) δ 11.4, 111.7, 118.6, 119.3, 125.4, 126.9,
128.1, 128.2, 130.3, 134.9, 135.9, 137.1, 138.4, 143.8, 147.4; LRMS (EI
70 eV) m/z (%) 218 (M+, 86), 203 (100).
3-Methyl-6-nitro-1,2-diphenyl-1H-indene (4ay). Yellow solid
1
(31.4 mg, 48% yield), mp 153.8−155.0 °C; H NMR (500 MHz,
CDCl3) δ 2.38 (s, 3H), 5.03 (s, 1H), 7.02 (d, J = 7.5 Hz, 2H), 7.13−
7.24 (m, 4H), 7.30−7.31 (m, 4H), 7.46 (d, J = 8.0 Hz, 1H), 8.01 (s,
1H), 8.25 (d, J = 8.5 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ 11.9,
57.9, 118.9, 119.1, 123.5, 127.2, 127.6, 128.0, 128.3 (2C), 128.9 (2C),
129.3, 134.8, 135.2, 137.7, 146.0, 148.6, 151.2, 152.4; LRMS (EI 70
eV) m/z (%) 328 (25), 327 (M+, 100), 310 (28); HRMS (ESI) calcd
for C22H18NO2 [M + H]+ 328.1332, found 328.1343.
3-Methyl-1,2-dipropyl-1H-indene (4eg).13 Colorless oil (15.4 mg,
1
36% yield); H NMR (500 MHz, CDCl3) δ 0.82 (t, J = 7.0 Hz, 3H),
0.92−0.96 (m, 4H), 1.06−1.16 (m, 1H), 1.39−1.48 (m, 1H), 1.56−
1.67 (m, 2H), 1.89−1.96 (m, 1H), 2.02 (s, 3H), 2.21−2.26 (m, 1H),
2.44−2.50 (m, 1H), 3.37 (s, 1H), 7.12 (t, J = 7.0 Hz, 1H), 7.20−7.26
(m, 2H), 7.36 (d, J = 7.5 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ
10.2, 14.1, 14.5, 18.1, 23.0, 28.6, 32.3, 49.3, 117.9, 122.4, 123.6, 126.1,
132.1, 146.0, 146.8, 146.9; LRMS (EI 70 eV) m/z (%) 214 (M+, 44),
185 (54), 143 (100).
(2,3-Dimethyl-1H-inden-1-yl)methanol (4fg). Colorless oil (15.0
mg, 43% yield); 1H NMR (500 MHz, CDCl3) δ 2.03 (s, 3H), 2.04 (s,
3H), 3.38 (s, 1H), 3.84−3.87 (m, 1H), 4.14−4.17 (m, 1H), 7.15 (t, J =
7.0 Hz, 1H), 7.21 (d, J = 7.5 Hz, 1H), 7.29 (t, J = 7.5 Hz, 1H), 7.44 (d,
J = 7.5 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ 10.2, 12.4, 54.8, 62.7,
118.2, 122.5, 124.1, 127.0, 134.0, 138.4, 143.5, 147.3; LRMS (EI 70
eV) m/z (%) 174 (M+, 70), 129 (99), 128 (100); HRMS (ESI) calcd
for C12H15O [M + H]+ 175.1117, found 175.1130.
3-Ethyl-6-methyl-1,2-diphenyl-1H-indene (4az). White solid (37.8
mg, 61% yield), mp 119.6−120.6 °C; 1H NMR (500 MHz, CDCl3) δ
1.34 (t, J = 7.0 Hz, 3H), 2.30 (s, 3H), 2.69−2.78 (m, 2H), 4.87 (s,
1H), 7.01−7.02 (m, 3H), 7.07 (t, J = 7.5 Hz, 1H), 7.11−7.15 (m, 4H),
7.23−7.24 (m, 4H), 7.31 (d, J = 7.5 Hz, 1H); 13C NMR (125 MHz,
CDCl3) δ 14.0, 19.4, 21.4, 57.9, 119.2, 124.7, 126.4, 126.5, 127.5,
128.1, 128.2, 128.4, 128.7, 135.0, 136.6, 140.2, 141.6, 142.2, 143.6,
148.7; LRMS (EI 70 eV) m/z (%) 310 (M+, 65), 281 (100); HRMS
(EI) calcd for C24H23 [M + H]+ 311.1794, found 311.1805.
1,2-Bis(1-phenylethylidene)hydrazone (6aa).16 Yellow solid (7.1
mg, 10% yield), mp 122.8−124.7 °C; 1H NMR (500 MHz, CDCl3) δ
2.32 (s, 6H), 7.40−7.44 (m, 6H), 7.90−7.92 (m, 4H); 13C NMR (125
MHz, CDCl3) δ 15.0, 126.6, 128.3, 129.6, 138.4, 157.7; LRMS (EI 70
eV) m/z (%) 236 (M+, 43), 221 (100).
2,3-Dimethyl-1-methylene-1H-indene (5fg). Colorless oil (3.1 mg,
10% yield); 1H NMR (500 MHz, CDCl3) δ 2.06 (s, 3H), 2.09 (s, 3H),
5.57 (s, 1H), 5.89 (s, 1H), 7.10−7.13 (m, 2H), 7.23 (t, J = 7.0 Hz,
1H), 7.50 (d, J = 7.5 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ 9.6,
10.5, 108.2, 117.5, 118.8, 124.6, 127.9, 131.8, 135.9, 137.1, 144.5,
148.5; LRMS (EI 70 eV) m/z (%) 156 (M+, 65), 141 (100); HRMS
(ESI) calcd for C12H13 [M + H]+ 157.1012, found 157.1020.
Methyl 3-Methyl-2-phenyl-1H-indene-1-carboxylate (4gg). White
ASSOCIATED CONTENT
■
S
* Supporting Information
The reaction determined in situ by HRMS analysis, kinetic
isotope effect experiments, and copies of spectra. This material
is available free of charge via the Internet at http://pubs.acs.org.
1
solid (27.5 mg, 52% yield), mp 85.8−87.0 °C; H NMR (500 MHz,
CDCl3) δ 2.61 (s, 3H), 3.65 (s, 3H), 4.83 (s, 1H), 7.05 (t, J = 8.0 Hz,
2H), 7.17−7.29 (m, 4H), 7.35 (t, J = 7.5 Hz, 1H), 7.51 (d, J = 7.5 Hz,
1H); 13C NMR (125 MHz, CDCl3) δ 12.5, 51.0, 55.9, 121.2, 124.2,
126.6, 127.1, 127.7, 128.4 (2C), 134.5, 139.5, 143.8, 149.0, 151.9,
165.8; LRMS (EI 70 eV) m/z (%) 264 (M+, 62), 205 (100); HRMS
(ESI) calcd for C18H17O2 [M + H]+ 265.1223, found 265.1236.
4-Methoxy-3-methyl-1,2-diphenyl-1H-indene (4au). White solid
AUTHOR INFORMATION
■
Corresponding Author
*E-mail: jhli@hnu.edu.cn.
Notes
1
(27.5 mg, 44% yield%), mp 104.8−106.6 °C; H NMR (500 MHz,
The authors declare no competing financial interest.
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(7) For papers on the synthesis of isoquinolines by transition-metal-
catalyzed annulation of alkynes with imines or oximines through aryl
C(sp2)−H bond activation and subsequent C−N bond formation, see:
(a) Guimond, N.; Fagnou, K. J. Am. Chem. Soc. 2009, 131, 12050.
(b) Wei, X.; Zhao, M.; Du, Z.; Li, X. Org. Lett. 2011, 13, 4636.
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ACKNOWLEDGMENTS
■
We thank the National Natural Science Foundation of China
(21172060), the Specialized Research Fund for the Doctoral
Program of Higher Education (20120161110041), and the
Hunan Provincial Natural Science Foundation of China
(13JJ2018) for financial support. X.-C.H. also thanks the
Hunan Provincial Innovation Foundation for Postgraduate
(CX2010B219).
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