Nickel-catalyzed cross-coupling of aryl or 2-menaphthyl quaternary ammonium triflates with organoaluminum reagents

Article abstract of DOI:10.1016/j.tet.2017.06.004

The cross-coupling of aryltrimethylammonium triflates with AlMe₃ and β-H-containing trialkylaluminums was performed in dioxane at 110 °C under catalysis of (dppp)NiCl₂ to afford alkylated arenes. The cross-coupling of 2-menaphthyltri

Full text of DOI:10.1016/j.tet.2017.06.004

Accepted Manuscript
Nickel-catalyzed cross-coupling of aryl or 2-menaphthyl quaternary ammonium
triflates with organoaluminum reagents
Fang He, Zhong-Xia Wang
PII:
S0040-4020(17)30623-3
10.1016/j.tet.2017.06.004
TET 28769
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 19 April 2017
Revised Date: 2 June 2017
Accepted Date: 5 June 2017
Please cite this article as: He F, Wang Z-X, Nickel-catalyzed cross-coupling of aryl or 2-menaphthyl
quaternary ammonium triflates with organoaluminum reagents, Tetrahedron (2017), doi: 10.1016/
j.tet.2017.06.004.
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ACCEPTED MANUSCRIPT
Graphical Abstract
Nickel-catalyzed cross-coupling of aryl or 2-menaphthyl
quaternary ammonium triflates with organoaluminum
reagents
a
a,b,
Fang He and Zhong-Xia Wang *
a
CAS Key Laboratory of Soft Matter Chemistry, Hefei National Laboratory for Physical Sciences at
Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui
2
30026, People’s Republic of China. Tel: 86 551 63603043; E-mail: zxwang@ustc.edu.cn.
b
Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072,
People’s Republic of China.

ACCEPTED MANUSCRIPT
Nickel-catalyzed cross-coupling of aryl or 2-menaphthyl
quaternary ammonium triflates with organoaluminum
reagents
a
a,b,
Fang He and Zhong-Xia Wang *
a
CAS Key Laboratory of Soft Matter Chemistry, Hefei National Laboratory for Physical Sciences at
Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui
2
30026, People’s Republic of China. Tel: 86 551 63603043; E-mail: zxwang@ustc.edu.cn.
b
Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072,
People’s Republic of China.
Abstract
The cross-coupling of aryltrimethylammonium triflates with AlMe and β-H-containing
3
trialkylaluminums was performed in dioxane at 110 °C under catalysis of (dppp)NiCl to
2
afford alkylated arenes. The cross-coupling of 2-menaphthyltrimethylammonium triflate with
trialkylaluminums and 1-naphthyltrimethylammonium triflate with triarylaluminums was also
carried out respectively under the same conditions.
Keywords: nickel; catalysis; cross-coupling; aryltrimethylammonium salt; trialkylaluminum
1
. Introduction
The catalytic activation and transformation of C–N bonds of amines have attracted
considerable attention in recent years. Amines are widely available from natural resources
and industrial products. The amino groups of aromatic amines and benzylamines are
important directing groups which direct the introduction of other functional groups onto the
1
,2
aromatic ring. Hence, the transformation of amines through catalytic activation of C−N
bonds is an attractive topic. However, direct cleavage of the C–N bond in an amine is rare
3
due to the inertness of the C–N bonds. An effective tactic is to transform amines to
ammonium salts, aryldiazonium salts or aryltriazenes to weaken the C–N bonds before
4
-27
catalytic cleavage.
Early in 1988 Wenkert et al. reported nickel-catalyzed Kumada
coupling of aryltrimethylammonium iodides with Grignard reagents in low to moderate
4
yields. In 2003 MacMillan et al. performed cross-coupling of aryltrimethylammonium
5
triflates with arylboronic acids using Ni(cod) /IMes catalyst. More recently, we and other
2
groups
developed
transition-metal-catalyzed
cross-coupling
of
aryl-
or
1

ACCEPTED MANUSCRIPT
benzyltrimethylammonium salts with various nucleophiles such as Grignard reagents,
7
-16
organozinc reagents, organoboron reagents, and organotin reagents.
On the other hand,
organoaluminum reagents exhibited high chemoselective reactivity and good compatibility of
functional groups in C-C bond formation reactions. Al also has low toxicity and is one of the
2
8,29
most inexpensive and earth-abundant metals.
However, compared with other
organometallic nucleophiles using in the cross-coupling utility of organoaluminum reagents
is limited. Successful reactions are largely restricted to the couplings of aryl- and
alkenylaluminum compounds, while those of alkylaluminum compounds are still rare. The
electrophilic partners in the cross-couplings using organoaluminum reagents are mainly
2
8-38
restricted to organic halides and triflates.
It is interesting to explore cross-coupling of
aryl- and benzyltrimethylammonium salts with organoaluminum reagents, especially
trialkylaluminums. Here we report the results.
2
. Results and discussion
Reaction of 1-naphthyltrimethylammonium triflate with AlMe was chosen as a model
3
reaction to screen catalyst and conditions. Nickel was often used in catalyzing the
cross-coupling of aryltrimethylammonium salts, while palladium was often employed to
2
9-34
catalyze reactions of organoaluminum reagents.
We chose more earth-abundant nickel to
test the catalytic reaction and the results are listed in Table 1. A combination of Ni(COD) and
2
IPr was demonstrated to catalyze the reaction and lead to 1-methylnaphthalene in 21% yield
(Table 1, entry 1). Better results were achieved when phosphines such as Xantphos and PCy3
were employed as the ligand (Table 1, entries 2 and 3). Further screening showed that
dioxane was better solvent than toluene. The reaction catalyzed by Ni(COD) /PCy in
2
3
dioxane led to 93% product yield (Table 1, entry 4). Ni(PCy ) Cl gave almost the same
3
2
2
catalytic result as the Ni(COD) /PCy combination (Table 1, entry 5). Ni(PPh ) Cl exhibited
2
3
3 2
2
lower catalytic activity than Ni(PCy ) Cl , while Ni(dppp)Cl revealed almost same activity
3
2
2
2
as Ni(PCy ) Cl (Table 1, entries 6 and 7). We also examined solvent effect when
3
2
2
Ni(dppp)Cl was employed as a catalyst. The results showed that dioxane is more effective
2
than toluene, hexane, DMF, DMAC, THF and Et O (Table 1, entries 8-13). Reaction
2
temperature is also an important factor to the reaction. Lower temperature than 100 °C
resulted in lower product yields (Table 1, entries 14 and 15). When reaction temperature was
raised to 110 °C, the product yield achieved 98% (Table 1, entry 16). Employing 1 equiv. of
AlMe or 2 mol% Ni(dppp)Cl as well as shortening reaction time led to decrease of the
3
2
product yields (Table 1, entries 17-19).
2

ACCEPTED MANUSCRIPT
Although Ni(PCy ) Cl exhibited almost same catalytic activity as Ni(dppp)Cl based on
3
2
2
2
above evaluation, we chose Ni(dppp)Cl as the catalyst for the next substrate extending
2
because (1) dppp is less expensive than PCy , and (2) Ni(dppp)Cl behaved better than
3
2
Ni(PCy ) Cl in catalyzing the reaction of β-H-containing AlR .
3
2
2
3
a
Table 1. Screening of reaction conditions
b
Entry
[Ni]
Ligand (mol%)
IPr⋅HCl (10)
Solvent
Toluene
Toluene
Toluene
Dioxane
Dioxane
Dioxane
Dioxane
Toluene
Hexane
DMF
Yield (%)
21
1
2
3
4
5
6
7
8
9
Ni(COD)2
Ni(COD)2
Ni(COD)2
Ni(COD)2
Ni(PCy ) Cl
Xantphos (5)
48
PCy (10)
76
3
PCy (10)
93
3
92
3
2
2
2
Ni(PPh ) Cl
85
3
2
Ni(dppp)Cl2
Ni(dppp)Cl2
Ni(dppp)Cl2
Ni(dppp)Cl2
Ni(dppp)Cl2
Ni(dppp)Cl2
Ni(dppp)Cl2
Ni(dppp)Cl2
Ni(dppp)Cl2
Ni(dppp)Cl2
Ni(dppp)Cl2
Ni(dppp)Cl2
Ni(dppp)Cl2
92
89
83
1
0
75
1
1
DMAC
87
c
1
1
1
1
1
1
1
2
3
4
5
6
7
8
9
THF
79
d
Et O
2
85
d
Dioxane
Dioxane
Dioxane
Dioxane
Dioxane
Dioxane
80
c
86
e
98
e,f
e,g
e,h
91
87
1
93
a
Unless otherwise specified, the reactions were carried out using 0.5 mmol of
-naphthyltrimethylammonium triflate and 1.5 equiv. of AlMe in 3 mL of solvent according
1
3
to the conditions indicated by the above equation.
b
Isolated yield.
The reaction temperature was 80 °C.
The reaction temperature was 50 °C.
The reaction temperature was 110 °C.
c
d
e
f
1.0 equiv. of AlMe was employed.
3
g
h
2
mol% of Ni(dppp)Cl was employed.
2
Reaction time was 12 h.
3

ACCEPTED MANUSCRIPT
Under the optimized conditions, we first examined reaction of AlMe with various
3
aryltrimethylammonium triflates. Both 2-naphthyltrimethylammonium triflate and
2
-anthryltrimethylammonium triflate exhibited good reactivity. Their reaction with AlMe3
afforded corresponding methylated products in excellent yields (Table 2, entries 1 and 2).
However, reaction of 2-(4-methoxynaphthyl)trimethylammonium triflate and 2-(N,N-di-
methylaminonaphthyl)trimethylammonium triflate resulted in relatively low product yields
(
Table 2, entries 3 and 4). This is ascribed to deactivation of MeO and Me N groups and
2
steric hindrance of Me N group in 2-(N,N-dimethylaminonaphthyl)trimethylammonium
2
triflate. Substituted phenyltrimethylammonium triflates exhibited lower reactivity than the
naphthyltrimethylammonium triflates (Table 2, entries 5-9). Some of the substrates include
reactive functional groups or heterocyclic group (Table 2, entries 6, 7 and 9). However, the
existence of side reactions led to relatively low product yields. For example, reaction of
+
–
4
-(4'-CF C H )C H NMe OTf with AlMe gave corresponding product in 64% yield
3 6 4 6 4 3 3
although 4'-CF C H is a activating group in the molecule. Some unidentified side products
3
6
4
were observed from TLC of the reaction mixture. The substrates containing carbonyl
functional groups such as COOEt and PhC(O) groups were not tolerated. No expected
+
–
cross-coupling products can be obtained when 4-EtO CC H NMe OTf
or
2
6
4
3
+
–
4
-PhC(O)C H NMe OTf were employed as the electrophilic substrates. The catalyst system
6
4
3
also suited for coupling of β-H-containing AlR . AlEt , AliBu and Al(n-C H ) were
3
3
3
8
17 3
selected as representatives of β-H-containing organoaluminum reagents to perform the
coupling reaction. The catalyst can well inhibit β-H elemination during the reaction process.
Reaction of 1-naphthyltrimethylammonium triflate with each of AlEt , AliBu , and
3
3
Al(nC H ) gave alkylated product in high yield (Table 2, entries 10-12). Reaction of
8
17 3
2
-naphthyltrimethylammonium triflate with AlEt and Al(nC H ) afforded corresponding
3 8 17 3
coupling products in excellent yields, but the reaction with AliBu led to relatively low yield
3
for unclear reason (Table 2, entries 13-15). 2-Anthryltrimethylammonium triflate exhibited
similar reactivity to 2-naphthyltrimethylammonium triflate when it reacted with AlEt , AliBu ,
3
3
and Al(nC H ) , giving 2-alkylanthracene in 79-86% yields (Table 2, entries 16-18). The
8
17 3
+
–
substituted
phenyltrimethylammonium
triflates,
4-PhC H NMe OTf ,
6 4 3
+
–
+
–
4
-(4'-MeOC H )C H NMe OTf and 4-(1-indolyl)C H NMe OTf were also tested. Their
6
4
6
4
3
6
4
3
reaction with AlEt afforded ethylated products in 53%-71% yields (Table 2, entries 19-21).
3
4

ACCEPTED MANUSCRIPT
a
Table 2. Reaction of aryltrimethylammonium triflates with trialkylaluminums
b
Entry
1
Ar
R
Product
Yield (%)
96
Me
2
3
Me
Me
87
68
Me
OMe
4
Me
40
5
6
Me
Me
78
64
c,d
7
Me
35
8
Me
Me
65
58
c
9
1
0
Et
Et
96
86
11
iBu
5

ACCEPTED MANUSCRIPT
1
2
nC H
94
8
17
1
1
1
1
1
1
1
3
4
5
6
7
8
9
Et
94
57
97
81
86
79
71
iBu
nC H
8
17
Et
e
iBu
nC H
8
17
Et
Et
2
0
1
62
53
c
2
Et
a
The reactions were carried out on a 0.5 mmol scale according to the conditions indicated by
the above equation.
b
Unless otherwise specified, the reported yield is isolated yield.
c
1
0 mol% of Ni(dppp)Cl were employed.
2
d
e
3
equiv of AlMe were employed
3
NMR yield.
As mentioned above, the substrates containing carbonyl functional groups such as COOEt
+
3
−
and PhC(O) groups were not tolerated. However, reaction of p-[BocN(Me)]C H NMe OTf
6
4
1
13
with AlMe gave an isolated product in 38% yield. Its H and C NMR spectra and HR-MS
3
showed that the species was p-MeC H NHMe (Scheme 1). That is to say, the Boc group was
6
4
lost in the process of reaction. In addition, the reaction required higher catalyst loading and
employed more AlMe in comparison with the standard conditions. Under the same
3
6

ACCEPTED MANUSCRIPT
+
−
conditions, the reaction of p-[BocN(Me)]C H NMe OTf with AlEt gave p-EtC H NHMe
6
4
3
3
6
4
in 33% yield (Scheme 1).
+
−
Scheme 1. Ni-catalyzed reaction p-[BocN(Me)]C H NMe OTf with AlR
3
6
4
3
Ni(dppp)Cl was also demonstrated to catalyze 2-menaphthyltrimethylammonium triflate
2
with trialkylaluminum under the same conditions as above. The reaction with AlMe gave
3
excellent result. However, the reactions with β-H-containing trialkylaluminums such as AlEt3
and Al(nC H ) gave only poor coupling yields. Reaction of 1-naphthyltrimethylammonium
8
17 3
triflate with triarylaluminums including Al(p-MeOC H ) , Al(p-MeC H ) , and
6
4 3
6
4 3
Al(m-MeC H ) was also evaluated. Reaction of Al(p-MeOC H ) and Al(p-MeC H )
4 3
6
4 3
6
4 3
6
afforded biaryls in excellent yields, and reaction of Al(m-MeC H ) led to moderate product
6
4 3
yield. The relatively low reactivity of the latter might be due to steric hindrance of m-MeC H4
6
or weaker nucleophilic ability of Al(m-MeC H ) compared to Al(p-MeOC H ) and
6
4 3
6
4 3
Al(p-MeC H ) .
6
4 3
Table 3. Reaction of 2-menaphthyltrimethylammonium triflate with trialkylaluminum and
a
1
-naphthyltrimethylammonium triflate with triarylaluminums.
1
Entry
1
R
R
Product
Yield (%)
b
Me
88
c
2
3
Et
40
c
nC H
20
8
17
7

ACCEPTED MANUSCRIPT
b
c
c
4
5
83
88
56
6
a
The reactions were carried out on a 0.5 mmol scale according to the conditions indicated by
the above equation.
b
Isolated yield.
c
NMR yield.
The detailed mechanism is not clear at this stage. We noted that Ni(0) or Ni(II) catalyst
precursors exhibited almost same catalytic results under comparable conditions (Table 1,
entries 4 and 5). This probably shows that the catalytic reaction proceeds via a Ni(0)/Ni(II)
cycle and a Ni(0) species may be the active catalyst. Based on this experimental fact and the
previous reports for the transition-metal-catalyzed cross-coupling of organometallic
1
6,38
reagents,
we proposed a catalytic cycle as shown in Scheme 2. Thus, (dppp)NiCl is
2
reduced by AlR to a Ni(0) species (dppp)Ni. The active catalyst (dppp)Ni reacts with
3
+
−
ArNMe OTf to generate an oxidative addition species (dppp)Ni(Ar)OTf and release NMe .
3
3
Reaction of (dppp)Ni(Ar)OTf with AlR affords (dppp)Ni(Ar)R which undergoes reductive
3
elemination to give cross-coupling product and regenerates (dppp)Ni(0).
NMe3
Ar
(dppp)Ni
Ar NMe OTf
OTf
3
AlR3
AlR3
(dppp)NiCl2
(dppp)Ni(0)
R AlOTf
2
Ar
R
(dppp)Ni
Ar R
Scheme 2. proposed catalytic cycle.
8

ACCEPTED MANUSCRIPT
3
. Conclusions
In summary, we developed an effective transformation method which led to cross-coupling of
aryltrimethylammonium triflates with trialkylaluminum reagents. Naphthyl, anthryl, and
substituted phenyltrimethylammonium salts can be used as the electrophiles. AlMe and
3
β-H-containing trialkylaluminum reagents are suitable nucleophiles. The catalyst system also
suited for the coupling of 2-menaphthyltrimethylammonium triflate with AlMe and
3
1
2
-naphthyltrimethylammonium triflate with triarylaluminum reagents, but reaction of
-menaphthyltrimethylammonium triflate with β-H-containing trialkylaluminum reagents
under the same conditions gave relatively low product yields. Functional groups such as CF3,
OCF and heterocyclic group 1-indolyl in the electrophilic substrates can be tolerated.
3
However, the substrates containing carbonyl functional groups such as COOEt and PhC(O)
+
−
groups were not tolerated. Reaction of p-[BocN(Me)]C H NMe OTf with AlMe or AlEt
3
6
4
3
3
resulted in Boc-losting cross-coupling products.
4
4
. Experimental
.1. General remarks
All reactions were performed under nitrogen atmosphere using standard Schlenk and vacuum
line techniques. THF, Et O and hexane were distilled under nitrogen over
2
sodium/benzophenone and degassed prior to use. Toluene and dioxane were distilled from
sodium and degassed prior to use. NMP, DMF and DMAC were dried over 4 Å molecular
sieves, fractionally distilled under reduced pressure, and stored under nitrogen atmosphere.
CDCl was purchased from Cambridge Isotope Laboratories. AlMe and AlEt were
3
3
3
purchased from Energy Chemical. AliBu was purchased from J & K Chemical. Al(nC H )
17 3
3
8
was purchased from Sigma-Aldrich Co. LLC. The chemicals mentioned above were used as
3
9
received. AlAr3 were prepared according to literature procedures.
benzyl)trimethylammonium triflates were prepared according to reported methods.
Aryl(or
7,40,41
All
other reagents and catalysts were purchased from commercial vendors and used as received.
NMR spectra were recorded at room temperature on a Bruker Avance III 400 NMR
1
13
spectrometer. The chemical shifts of the H and C NMR spectra were referenced to internal
solvent resonances. HR-MS data were recorded on a Waters Xevo G2 QTof mass
spectrometer (ESI).
4
.2. Typical procedure for the reaction of aryltrimethylammonium triflates with
9

ACCEPTED MANUSCRIPT
organoaluminum reagents
A Schlenk tube was successively charged with aryl(or 2-menaphthyl)trimethylammonium
triflate (0.5 mmol), Ni(dppp)Cl (5 mol%), dioxane (3 mL), and organoaluminum reagent
2
(0.75 mmol). The mixture was heated at 110 °C (bath temperature) for 24 h with stirring and
then cooled to room temperature. Water (10 mL) was added and the resultant mixture was
extracted with Et O (10 mL × 3). The combined organic phases were dried over anhydrous
2
Na SO , concentrated by rotary evaporation, and purified by column chromatography on
2
4
silica gel.
4
2 1
4
7
3
1
4
8
1
1
4
7
3
1
4
7
.2.1. 1-Methylnaphthalene. H NMR (400 MHz, CDCl ): δ 8.09 (d, J = 8.0 Hz, 1H),
3
.98-7.92 (m, 1H), 7.81 (d, J = 8.1 Hz, 1H), 7.65-7.55 (m, 2H), 7.52-7.38 (m, 2H), 2.79 (s,
1
3
H). C NMR (101 MHz, CDCl ): δ 134.36, 133.67, 132.73, 128.64, 126.68, 126.50, 125.82,
3
25.69, 125.65, 124.22, 19.49.
4
3 1
.2.2. 2-Methylanthracene. H NMR (400 MHz, CDCl ): δ 8.40 (s, 1H), 8.33 (s, 1H),
3
.04-7.97 (m, 2H), 7.93 (d, J = 8.8 Hz, 1H). 7.77 (s, 1H), 7.51-7.42 (m, 2H), 7.33 (dd, J = 8.7,
1
3
.4 Hz, 1H), 2.57 (s, 3H). C NMR (101 MHz, CDCl ): δ 135.04, 132.11, 131.96, 131.35,
3
30.45, 128.38, 128.31, 128.18, 128.09, 126.45, 126.07, 125.36, 125.29, 125.04, 22.13.
4
4 1
.2.3. 2-Methylnaphthalene. H NMR (400 MHz, CDCl ): δ 7.82 (d, J = 8.0 Hz, 1H),
3
.80-7.74 (m, 2H), 7.64 (s, 1H), 7.50-7.40 (m, 2H), 7.34 (dd, J = 8.4, 1.5 Hz, 1H), 2.54 (s,
1
3
H). C NMR (101 MHz, CDCl ): δ 135.57, 133.78, 131.81, 128.24, 127.81, 127.73, 127.36,
3
26.96, 125.99, 125.08, 21.86.
4
5 1
.2.4. 1-Methoxy-4-methylnaphthalene. H NMR (400 MHz, CDCl ): δ 8.33-8.25 (m, 1H),
3
.93-7.84 (m, 1H), 7.56-7.42 (m, 2H), 7.17 (d, J = 7.7 Hz, 1H), 6.66 (d, J = 7.7 Hz, 1H), 3.92
1
3
(
s, 3H), 2.58 (s, 3H). C NMR (101 MHz, CDCl ): δ 154.15, 133.44, 126.34, 126.19, 126.11,
3
1
25.81, 124.98, 124.09, 122.51, 103.47, 55.52, 18.94.
4
6 1
4
.2.5. N,N,8-Trimethylnaphthalen-1-amine. H NMR (400 MHz, CDCl ): δ 7.70 (d, J = 8.0
3
Hz, 1H), 7.58 (d, J = 7.7 Hz, 1H), 7.43-7.33 (m, 2H), 7.28 (d, J = 6.8 Hz, 1H), 7.23 (d, J =
1
3
7
1
4
.4 Hz, 1H), 3.01 (s, 3H), 2.76 (s, 6H). C NMR (101 MHz, CDCl ): δ 152.67, 136.48,
3
35.25, 129.29, 129.25, 127.02, 125.37, 125.32, 124.56, 116.35, 45.82, 23.35.
4
7 1
.2.6. 4-Methylbiphenyl. H NMR (400 MHz, CDCl ): δ 7.67-7.62 (m, 2H), 7.56 (d, J = 8.1
3
Hz, 2H), 7.49 (t, J = 7.6 Hz, 2H), 7.38 (t, J = 7.4 Hz, 1H), 7.31 (d, J = 7.9 Hz, 2H), 2.46 (s,
1
3
3
1
4
H). C NMR (101 MHz, CDCl ): δ 141.28, 138.47, 137.13, 129.61, 128.88, 128.84, 127.12,
3
27.10, 21.23.
11 1
.2.7. 4-Methyl-4'-(trifluoromethyl)biphenyl. H NMR (400 MHz, CDCl ): δ 7.69 (s, 4H),
3
1
0

ACCEPTED MANUSCRIPT
1
3
7
.52 (d, J = 8.1 Hz, 2H), 7.33-7.27 (m, 2H), 2.43 (s, 3H). C NMR (101 MHz, CDCl ): δ
3
1
44.78, 138.30, 136.99, 129.85, 129.16 (q, J = 32.6 Hz) , 127.77, 127.30, 127.24, 125.80 (q,
1
9
J = 3.7 Hz), 124.50 (q, J = 273.1 Hz), 21.28. F NMR (376 MHz, CDCl ): δ –62.33.
3
4
8 1
4
.2.8. 4-Methyl-4'-(trifluoromethoxy)biphenyl. H NMR (400MHz, CDCl ): δ 7.57 (d, J =
3
1
3
8
.4 Hz, 2H), 7.45 (d, J = 7.6 Hz, 2H), 7.30-7.21 (m, 4H), 2.40 (s, 3H). C NMR (101 MHz,
CDCl ): δ 148.55, 140.05, 137.66, 137.10, 129.75, 128.36, 127.08, 121.35, 120.68 (q, J =
3
2
4
2
2
1
4
58.0 Hz), 21.25.
4
9 1
.2.9. 4-Methoxy-4'-methyl-biphenyl. H NMR (400 MHz, CDCl ): δ 7.51 (d, J = 8.8 Hz,
3
H), 7.45 (d, J = 8.0 Hz, 2H), 7.23 (d, J = 8.0 Hz, 2H), 6.97 (d, J = 8.8 Hz, 2H), 3.85 (s, 3H),
13
.39 (s, 3H). C NMR (101 MHz, CDCl ): δ 159.04, 138.09, 136.50, 133.87, 129.57, 128.10,
3
26.72, 114.28, 55.49, 21.20.
5
0 1
.2.10. 1-p-Tolyl-1H-indole. H NMR (400MHz, CDCl ): δ 7.67 (d, J = 7.6 Hz, 1H), 7.52 (d,
3
1
3
J = 8.4 Hz, 1H), 7.41-7.23 (m, 5H), 7.23-7.10 (m, 2H), 6.69-6.61 (m, 1H), 2.40 (s, 3H). C
NMR (101MHz, CDCl ): δ 137.37, 136.39, 136.05, 130.24, 129.71, 129.28, 128.16, 124.40,
3
1
4
7
22.31, 121.17, 120.46, 120.29, 110.62, 103.30, 21.17.
5
1 1
.2.11. 1-Ethylnaphthalene. H NMR (400 MHz, CDCl ): δ 8.11 (d, J = 8.2 Hz, 1H),
3
.93-7.88 (m, 1H), 7.76 (d, J = 8.1 Hz, 1H), 7.59-7.49 (m, 2H), 7.46 (t, J = 7.6 Hz, 1H), 7.39
1
3
(
d, J = 6.9 Hz, 1H), 3.17 (q, J = 7.5 Hz, 2H), 1.44 (t, J = 7.5 Hz, 3H). C NMR (101 MHz,
CDCl ): δ 140.40, 133.95, 131.91, 128.88, 126.52, 125.80, 125.52, 124.98, 123.87, 26.03,
3
1
4
7
5.18.
5
2 1
.2.12. 1-Isobutylnaphthalene. H NMR (400 MHz, CDCl ): δ 8.11 (d, J = 8.3 Hz, 1H),
3
.95-7.89 (m, 1H), 7.78 (d, J = 8.2 Hz, 1H), 7.60-7.50 (m, 2H), 7.46 (t, J = 7.6 Hz, 1H), 7.35
1
3
(
d, J = 6.9 Hz, 1H), 3.00 (d, J = 7.2 Hz, 2H), 2.21-2.09 (m, 1H), 1.05 (d, J = 6.6 Hz, 6H). C
NMR (101 MHz, CDCl ): δ 137.94, 134.07, 132.34, 128.85, 127.18, 126.65, 125.65, 125.45,
3
1
4
7
25.42, 124.31, 42.72, 29.60, 22.98.
1
2 1
.2.13. 1-Octylnaphthalene. H NMR (400 MHz, CDCl ): δ 8.14 (d, J = 8.2 Hz, 1H),
3
.97-7.90 (m, 1H), 7.79 (d, J = 8.1 Hz, 1H), 7.63-7.52 (m, 2H), 7.48 (t, J = 8.2 Hz, 1H), 7.41
(d, J = 6.8 Hz, 1H), 3.16 (t, J = 7.8 Hz, 2H), 1.93-1.78 (m, 2H), 1.61-1.31 (m, 10H), 1.00 (t, J
1
3
=
6.8 Hz, 3H). C NMR (101 MHz, CDCl ): δ 139.16, 134.03, 132.06, 128.87, 126.51,
3
1
1
4
7
3
25.95, 125.73, 125.66, 125.46, 124.04, 33.29, 32.08, 31.03, 30.03, 29.70, 29.49, 22.85,
4.29.
5
3 1
.2.14. 2-Ethylnaphthalene. H NMR (400 MHz, CDCl ): δ 7.95-7.85 (m, 3H), 7.74 (s, 1H),
3
.59-7.49 (m, 2H), 7.46 (dd, J = 8.4, 1.7 Hz, 1H), 2.92 (q, J = 7.6 Hz, 2H), 1.45 (t, J = 7.6 Hz,
1
3
H). C NMR (101 MHz, CDCl ): δ 141.86, 133.84, 132.07, 127.93, 127.73, 127.55, 127.20,
3
11

ACCEPTED MANUSCRIPT
1
4
1
1
1
4
7
1
1
2
4
8
=
25.95, 125.66, 125.13, 29.17, 15.67.
5
4 1
.2.15. 2-Isobutylnaphthalene. H NMR (400 MHz, CDCl ): δ 7.89-7.76 (m, 3H), 7.63 (s,
3
H), 7.53-7.42 (m, 2H), 7.35 (d, J = 8.4 Hz, 1H), 2.69 (d, J = 7.2 Hz, 2H), 2.10-1.96 (m, 1H),
1
3
.00 (d, J = 6.6 Hz, 6H). C NMR (101 MHz, CDCl ): δ 139.41, 133.67, 132.09, 128.09,
3
27.72, 127.70, 127.57, 127.32, 125.90, 125.13, 45.75, 30.34, 22.59.
5
5 1
.2.16. 2-Octylnaphthalene. H NMR (400 MHz, CDCl ): δ 7.94-7.82 (m, 3H), 7.72 (s, 1H),
3
.59-7.48 (m, 2H), 7.44 (dd, J = 8.4, 1.6 Hz, 1H), 2.88 (t, J = 7.7 Hz, 2H), 1.89-1.76 (m, 2H),
1
3
.55-1.32 (m, 10H), 1.02 (t, J = 6.9 Hz, 3H). C NMR (101 MHz, CDCl ): δ 140.57, 133.79,
3
32.07, 127.85, 127.73, 127.58, 127.53, 126.41, 125.91, 125.09, 36.29, 32.08, 31.57, 29.70,
9.54, 29.46, 22.86, 14.29.
5
6 1
.2.17. 2-Ethylanthracene. H NMR (400 MHz, CDCl ): δ 8.39 (s, 1H), 8.36 (s, 1H),
3
.04-7.90 (m, 3H), 7.78 (s, 1H), 7.50-7.41 (m, 2H), 7.36 (dd, J = 8.7, 1.5 Hz, 1H), 2.87 (q, J
1
3
7.5 Hz, 2H), 1.39 (t, J = 7.5 Hz, 3H). C NMR (101 MHz, CDCl ): δ 141.25, 132.19,
3
1
1
4
8
1
31.98, 131.42, 130.72, 128.32, 128.21, 128.20, 127.42, 126.05, 125.54, 125.34, 125.08,
25.04, 29.34, 15.26.
5
7 1
.2.18. 2-Octylanthracene. H NMR (400 MHz, CDCl ): δ 8.42 (s, 1H), 8.37 (s, 1H),
3
.07-8.00 (m, 2H), 7.97 (d, J = 8.7 Hz, 1H), 7.79 (s, 1H), 7.53-7.43 (m, 2H), 7.37 (dd, J = 8.7,
.6 Hz, 1H), 2.85 (t, J = 7.7 Hz, 2H), 1.85-1.73 (m, 2H), 1.50-1.27 (m, 10H), 0.96 (t, J = 6.9
1
3
Hz, 3H). C NMR (101 MHz, CDCl ): δ 139.95, 132.11, 131.94, 131.37, 130.69, 128.30,
3
1
2
4
28.18, 128.13, 127.69, 126.03, 125.88, 125.49, 125.30, 125.01, 36.45, 32.06, 31.15, 29.69,
9.56, 29.45, 22.85, 14.29.
5
1 1
.2.19. 4-Ethylbiphenyl. H NMR (400 MHz, CDCl ): δ 7.70-7.64 (m, 2H), 7.60 (d, J = 8.1
3
Hz, 2H), 7.50 (t, J = 7.6 Hz, 2H), 7.44-7.33 (m, 3H), 2.78 (q, J = 7.6 Hz, 2H), 1.36 (t, J = 7.6
1
3
Hz, 3H). C NMR (101 MHz, CDCl ): δ 143.49, 141.32, 138.75, 128.83, 128.41, 127.20,
3
1
4
2
2
1
4
7
=
27.13, 127.09, 28.65, 15.71.
5
8 1
.2.20. 4-Methoxy-4'-ethyl-biphenyl. H NMR (400 MHz, CDCl ): δ 7.52 (d, J = 8.8 Hz,
3
H), 7.48 (d, J = 8.1 Hz, 2H), 7.25 (d, J = 8.0 Hz, 2H), 6.97 (d, J = 8.8 Hz, 2H), 3.85 (s, 3H),
1
3
.68 (q, J = 7.6 Hz, 2H), 1.27 (t, J = 7.6 Hz, 3H). C NMR (101 MHz, CDCl ): δ 159.04,
3
42.89, 138.35, 133.91, 128.38, 128.13, 126.80, 114.27, 55.48, 28.62, 15.78.
5
9 1
.2.21. 1-(4-Ethylphenyl)-1H-indole. H NMR (400MHz, CDCl ): δ7.68 (d, J = 7.2 Hz, 1H),
3
.54 (d, J = 8.0 Hz, 1H), 7.44-7.25 (m, 5H), 7.25-7.10 (m, 2H), 6.69-6.61 (m, 1H), 2.71 (q, J
1
3
7.6 Hz, 2H), 1.29 (t, J = 7.6 Hz, 3H). C NMR (101 MHz, CDCl ): δ 142.73, 137.55,
3
1
1
36.06, 129.28, 129.07, 128.19, 124.48, 122.31, 121.16, 120.29, 110.66, 103.30, 28.58,
5.75.
1
2

ACCEPTED MANUSCRIPT
6
0 1
4
2
2
4
6
.2.22. N,4-Dimethylaniline. H NMR (CDCl ): 7.01 (d, J = 8.4 Hz, 2H), 6.56 (d, J = 8.4 Hz,
3
1
3
H), 2.82 (s, 3H), 2.25 (s, 3H). C NMR (CDCl ): 147.25, 129.81, 126.62, 112.74, 31.25,
3
+
0.62. HR-MS: m/z 122.0968 [M+H] , calcd for C H N: 122.0970.
8
12
61 1
.2.23. 4-Ethyl-N-methylaniline. H NMR (400MHz, CDCl ): δ 7.04 (d, J = 8.4 Hz, 2H),
3
1
3
.58 (d, J = 8.4 Hz, 2H), 2.82 (s, 3H), 2.55 (q, J = 7.6 Hz, 2H), 1.19 (t, J = 7.6 Hz, 3H). C
NMR (101MHz, CDCl ): δ 147.46, 133.31, 128.66, 112.73, 31.22, 28.08, 16.18. HR-MS: m/z
3
+
1
36.1127 [M+H] , calcd for C H N: 136.1126.
9
14
5
7 1
4
.2.24. 1-(4-Methoxyphenyl)naphthalene. H NMR (400 MHz, CDCl ): δ 7.94 (d, J = 8.5
3
Hz, 1H), 7.91 (d, J = 8.7 Hz, 1H), 7.85 (d, J = 8.2 Hz, 1H), 7.58-7.39 (m, 6H), 7.05 (d, J =
1
3
8
1
1
.7 Hz, 2H), 3.91 (s, 3H). C NMR (101 MHz, CDCl ): δ 159.05, 140.03, 133.96, 133.24,
3
31.94, 131.24, 128.39, 128.29, 127.46, 127.04, 126.87, 126.20, 126.05, 125.83, 125.54,
13.84, 55.50.
Acknowledgements
This research was supported by the National Natural Science Foundation of China (grant no.
2
1372212) and the National Basic Research Program of China (grant no. 2015CB856600).
Supplementary data
Supplementary data associated with this article can be found in the online version, at
http://dx.doi.org/xxxxxx.
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