Copper-Promoted Synthesis of 2-Fulleropyrrolines via Heteroannulation of [60]Fullerene with α-Amino Ketones

Article abstract of DOI:10.1021/acs.joc.7b01237

A Cu(OAc)₂-promoted heteroannulation of [60]fullerene with α-amino ketones has been exploited for the efficient synthesis of 2-fulleropyrrolines containing a trisubstituted or tetrasubstituted C=C bond via the formation of C-C and C-N bonds. Mechanistic study indicates that a radical process should be involved in this transformation. Furthermore, theoretical computations show that the process via the attack of the carbon radical generated from the employed α-amino ketone to [60]fullerene should be the preferred pathway. The electrochemical properties of the synthesized 2-fulleropyrrolines have also been investigated.

Full text of DOI:10.1021/acs.joc.7b01237

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Article
Copper-Promoted Synthesis of 2-Fulleropyrrolines via
Heteroannulation of [60]Fullerene with #-Amino Ketones
Sheng-Peng Jiang, Qing-Hua Wu, and Guan-Wu Wang
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.7b01237 • Publication Date (Web): 13 Sep 2017
Downloaded from http://pubs.acs.org on September 14, 2017
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CopperꢀPromoted Synthesis of 2ꢀFulleropyrrolines via
Heteroannulation of [60]Fullerene with αꢀAmino Ketones
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†
†
,†,‡
ShengꢀPeng Jiang, QingꢀHua Wu, and GuanꢀWu Wang*
†
CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of
Chemistry for Energy Materials, Hefei National Laboratory for Physical Sciences at
Microscale, and Department of Chemistry, University of Science and Technology of
China, Hefei, Anhui 230026, P. R. China
Eꢀmail: gwang@ustc.edu.cn;
‡
State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou,
Gansu 730000, P. R. China
ABSTRACT
A
Cu(OAc) ꢀpromoted heteroannulation of [60]fullerene with αꢀamino ketones
2
has been exploited for the efficient synthesis of 2ꢀfulleropyrrolines containing a
trisubstituted or tetrasubstituted C=C bond via the formation of C–C and C–N
bonds. Mechanistic study indicates that a radical process should be involved in
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this transformation. Furthermore, theoretical computations show that the process
via the attack of the carbon radical generated from the employed αꢀamino ketone
to [60]fullerene should be the preferred pathway. The electrochemical properties
of the synthesized 2ꢀfulleropyrrolines have also been investigated.
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INTRODUCTION
Owing to their huge potential applications in materials, biology, and
nanoscience, a diversity of fullerene derivatives have been synthesized through
1
different types of reactions over the past two decades. Free radical reaction,
one of the first investigated reactions of fullerenes, represents the most
powerful and straightforward protocol for the construction of diversified
2
fullerene
derivatives.
Especially
in
recent
years,
the
transitionꢀmetalꢀcatalyzed/promoted radical reactions exhibit excellent ability
to create novel functionalized fullerenes, attributed to their remarkable
advantages such as high compatibility with a wide range of functional
2bꢀe
3
4
5
groups.
The transition metals such as Mn(III), Fe(II)/Fe(III), Co(0),
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8
9
Ni(0), Cu(I)/Cu(II), Ag(I), and Pb(IV) have been continuously utilized to
functionalize fullerenes due to their ready availability, cheap price, and ease of
manipulation. Despite these advances, further exploration and development of
new transitionꢀmetalꢀcatalyzed/promoted synthetic methodologies still remain
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highly demanded for the construction of structurally diversified fullerene
derivatives.
The synthesis of C60ꢀfused pyrroline derivatives containing a nitrogen
atom bonded directly to the fullerene skeleton has rarely been reported. In 2006,
our group firstly realized the synthesis of 2ꢀfulleropyrrolines via the
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60
3
b
3
Mn(OAc) ꢀmediated reaction of C60 with βꢀenamino carbonyl compounds.
Subsequently, the Yang group described the preparation of 2ꢀfulleropyrrolines
through the reaction of C60 with amines and dimethyl acetylenedicarboxylate
7
d
(
DMAD) in the presence of CuCl2. Nevertheless, the aboveꢀmentioned
approaches only led to the formation of 2ꢀfulleropyrrolines with a
tetrasubstituted C=C bond. More recently, the Li group successfully developed
the synthesis of 2ꢀfulleropyrrolines with a trisubstituted C=C bond through the
7
h
2
Cu(OAc) ꢀmediated reaction of C60 with aldehydes and primary amines. It
should be noted that the unsubstituted position is located at the C2 of the
pyrroline moiety. The synthesis of 2ꢀfulleropyrrolines with unsubstituted
position located at the C3 of the pyrroline moiety has never been reported until
now. The unsubstituted olefinic carbon of the pyrroline moiety has the potential
to undergo postfunctionalizations. Recently, we disclosed the synthesis of
1ꢀfulleropyrrolines from the reaction of C60 and ketoxime acetates in the
7f
presence of CuBr and NaHSO
3
. As a part of our continuing interest in the
7
a,f
Cu(I)/Cu(II) catalyzed/promoted reactions of C60
,
herein we describe a facile
and efficient protocol to construct 2ꢀfulleropyrrolines containing a trisubstituted
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or tetrasubstituted C=C bond by the Cu(OAc)
ꢀamino ketones.
2
ꢀpromoted heteroannulation of
C60 with α
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RESULTS AND DISCUSSION
In the initial investigation, αꢀphenylamino propiophenone (1a) was chosen as a
representative substrate to react with C60 for the desired heteroannulation.
7f
Encouraged by our previous work on the CuBrꢀmediated reaction of C60, we
started the reaction of C (0.05 mmol) with 1a (2 equiv) by using CuBr as the
60
initiator (2 equiv) in anhydrous chlorobenzene (CB) at 130 °C under an
openꢀair atmosphere (Table 1, entry 1). Unfortunately, we did not observe any
desired product. Then, different copper salts were investigated to induce the
reaction. To our disappointment, neither Cu(I) salts such as CuCl, CuI, and
Cu O nor Cu(II) salts including CuBr , CuCl , CuCl ·2H O, and CuO could
2
2
2
2
2
2
promote the reaction (Table 1, entries 2–8). When Cu(OTf) was employed,
only a trace amount of 2a was observed (Table 1, entry 9). Gratifyingly, a
dramatic enhancement in the product yield (34%) was obtained in the presence
2 2 2
of Cu(OAc) ·H O (Table 1, entry 10). When anhydrous Cu(OAc) was used as
the promoter, a slightly lower yield of 2a (32%) was achieved (Table 1, entry 11
vs. entry 10). Taking its cheap price and insensitivity to air and moisture as well
as the higher product yield based on the consumed C60 into account,
Cu(OAc)
2
·H
2
O was selected to be the optimal promoter. The yield of the
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anticipated product 2a was lowered slightly to 28% upon decreasing the
reaction temperature from 130 °C to 120 °C (Table 1, entry 12). Likewise, it
was not beneficial to the reaction efficiency by raising the reaction temperature
to 140 °C (Table 1, entry 13). Other reaction parameters including reaction time,
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2 2
the amounts of 1a and Cu(OAc) ·H O were also systematically varied. It was
found that reducing or increasing the reaction time could not improve the
product yield of 2a, giving the desired product in 27% and 28% yields,
respectively (Table 1, entries 14 and 15). When 1.0 equiv of 1a was used, the
yield of 2a dropped significantly to 19% (Table 1, entry 16). A nearly same
yield (35%) was obtained in the presence of 3.0 equiv of 1a (Table 1, entry 10
2 2
vs. entry 17). The change of the amount of Cu(OAc) ·H O could not provide a
better result (Table 1, entries 18 and 19). Thus, the optimized reaction
conditions were determined as follows: C60 (0.05 mmol), 2 equiv of 1a and 2
equiv of Cu(OAc) ·H O in CB (6 mL) at 130 °C for 5 h under an openꢀair
2
2
atmosphere.
a
Table 1. Optimization for the Reaction of C with 1a
60
c
b
entry
1
Additive
CuBr
molar ratio
yield of 2a (%)
1:2:2
0 (0)
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CuCl
CuI
1:2:2
1:2:2
1:2:2
1:2:2
1:2:2
1:2:2
1:2:2
1:2:2
1:2:2
1:2:2
1:2:2
1:2:2
1:2:2
1:2:2
1:1:2
1:3:2
1:2:1
1:2:3
0 (0)
0 (0)
Cu
2
O
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CuBr
2
0 (0)
CuCl
2
0 (0)
CuCl
CuO
Cu(OTf)
2
·2H
2
O
0 (0)
0 (0)
2
trace (trace)
34 (81)
32 (67)
28 (80)
29 (53)
27 (64)
28 (62)
19 (61)
35 (65)
27 (50)
25 (54)
1
0
Cu(OAc)
2
·H
2
O
11
Cu(OAc)
2
d
12
Cu(OAc)
Cu(OAc)
Cu(OAc)
2
2
2
·H
·H
·H
2
2
2
O
O
O
e
f
13
14
g
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Cu(OAc) ·H O
2
2
1
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Cu(OAc)
2
·H
2
O
1
7
Cu(OAc) ·H O
2 2
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Cu(OAc) ·H O
2 2
1
9
Cu(OAc) ·H O
2 2
a
Unless otherwise noted, the reactions were performed in anhydrous CB (6 mL)
b
at 130 °C under an openꢀair atmosphere for 5 h. Molar ratio refers to
c
C
60
:
1a:additive. Isolated yields. Values in parentheses were based on the
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d
e
consumed C60. The reaction was performed at 120 °C. The reaction was
f
g
performed at 140 °C. The reaction time was 3 h. The reaction time was 7 h.
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We next turned our attention to explore the substrate scope of this protocol
under the optimized conditions. As shown in Table 2, the reaction of
α
ꢀarylamino propiophenones bearing both electronꢀdonating groups and
electronꢀwithdrawing group on the aryl ring proceeded efficiently under the
optimal conditions and furnished the corresponding 2ꢀfulleropyrrolines in 31–
40% yields. 1ꢀPhenylꢀ2ꢀ(
yield than the metaꢀ and paraꢀmethyl substituted substrates 1c and 1d
indicating that the reaction was not sensitive to the steric effect of the ꢀaryl
oꢀtolylamino)propanꢀ1ꢀone 1b gave a slightly higher
,
N
moiety. Compared with substrate 1e with a strong electronꢀrich methoxy (OMe)
substituent and substrates 1b–d with a methyl group on the phenyl ring,
substrate 1f bearing an electronꢀwithdrawing group (Cl) showed a comparable
reactivity, suggesting that the electronic effect of the substituent at the
Nꢀaryl
ring had little influence on the reaction efficiency. The chloro atom was inert
under our employed conditions, thus the chloroꢀcontaining product may be
further manipulated and provide new functionalized products. The
transformation of a 3,5ꢀdiꢀmethylꢀsubstituted substrate 1g underwent well and
gave the desired product 2g in a higher yield (40%). When
2ꢀ((3,5ꢀdimethylphenyl)amino)ꢀ1ꢀ(pꢀtolyl)propanꢀ1ꢀone 1h was employed as
the substrate to react with C60, the reaction proceeded smoothly to generate the
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desired product 2h in 37% yield. To our delight, the
Nꢀalkyl substituted
α
ꢀamino ketone 1i was also compatible with this protocol, affording product 2i
in 17% yield. It should be noted that the butyrophenone analogues 1j and 1k
were applicable, and the increase of the amounts of Cu(OAc) ·H O, 1j and 1k
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to 3 equiv was necessary to provide a synthetically valuable yields of 18% and
3
2
2% for 2j and 2k. Gratifyingly, when substrates with R as an aryl group such
as 1l and 1m were used, their reactivity increased obviously, providing the
corresponding products 2l and 2m in 40% and 43% yields, respectively.
Table 2. Results for the Reaction of C60 with αꢀAmino Ketones 1a–m Promoted
a,b
2 2
by Cu(OAc) ·H O
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a
Unless otherwise noted, the reactions were performed with C60 (0.05 mmol), 1 (0.10
b
mmol), Cu(OAc)
2
·H
2
O (0.10 mmol) in anhydrous CB at 130 °C. Isolated yields.
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c
Values in parentheses were based on the consumed C60. C60 (0.05 mmol), 1 (0.15
2 2
mmol), Cu(OAc) ·H O (0.15 mmol).
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The structures of products 2a
–
m
were fully characterized by HRMS (ESI
1
13
or MALDIꢀTOF), H NMR, C NMR, FTꢀIR, and UVꢀvis spectra. All HRMS
+
+
1
of these products gave the correct [M+H] or [M] peaks. Their H NMR
spectra displayed the expected chemical shifts as well as the splitting patterns
13
for all protons. The C NMR spectra of 2a and 2d
–
m
exhibited no more than
2
2
9 peaks in the range of 135–150 ppm for the 58 sp ꢀcarbons of the fullerene
3
cage and two peaks at 74–79 ppm and 88–91 ppm for the two sp ꢀcarbons of
1
3
the fullerene skeleton, consistent with their
s
C symmetry. In the C NMR
spectra of 2b and 2c, there were more than 39 peaks in the range of 135–150
2
ppm with some overlapping ones for the 58 sp ꢀcarbons of the fullerene cage
3
and two peaks at 74–75 ppm and 90–91 ppm for the two sp ꢀcarbons of the
fullerene skeleton, consistent with their
1
C symmetry due to the unsymmetrical
nature of
N
ꢀaryl moiety in 2b and 2c. The chemical shifts at 74–79 ppm and
3
88–91 ppm for the two sp ꢀcarbons of the fullerene skeleton were close to the
reported data of other fullerene derivatives with a nitrogen atom and a carbon
3
b,7d–f,h
atom attached to the fullerene skeleton.
The singlets at 5.90–6.56 ppm in
1
H NMR spectra, the signals at 108.9–119.6 ppm and 147.2–148.5 ppm in the
13
ꢀ1
C NMR spectra as well as the stretching vibrations at 1592–1601 cm in the
IR spectra demonstrated the existence of the C=C–H group. The chemical shifts
1
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for the carbonyl group attached to the pyrrolines moiety appeared at 186.6–
ꢀ
1
1
89.6 ppm. In the IR spectra, the strong absorption at 1646–1669 cm also
confirmed the presence of the carbonyl group. The structural assignment was
further confirmed by the HSQC and HMBC spectra using 2a as a representative
example. The HSQC spectrum of 2a displayed that the proton at 6.55 ppm had
a correlation with the olefinic carbon at 114.7 ppm, proving that the proton was
attached to the C=C group. The HMBC spectrum of 2a showed that the proton
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3
at 6.55 ppm was correlated with two sp ꢀcarbons of C60 at 75.0 ppm and 90.1
ppm, one carbon at 147.8 ppm as well as the carbonyl carbon at 187.3 ppm.
These 2DꢀNMR results were fully consistent with that 2a had a structure of
2ꢀfulleropyrroline. Their UVꢀvis spectra showed a peak at 426−429 nm, which
is the characteristic absorption for a 1,2ꢀadduct of C60
.
In order to gain insight into the reaction mechanism, some control
experiments were subsequently performed (Scheme 1). When 2 equiv of
2,2,6,6ꢀtetramethylpiperidineꢀ1ꢀoxyl (TEMPO) was added as a free radical
scavenger into the reaction system under the standard conditions, the reaction
was suppressed to a great extent, and the desired product 2a was obtained in
only 4% yield. In the presence of another free radical scavenger
2,6ꢀdiꢀtertꢀbutylꢀ4ꢀmethylphenol (BHT), the formation of 2a was also severely
inhibited, giving 2a in 6% yield. These results implied that this reaction might
proceed through a radical pathway. In addition, the oxidative product 3a could
2 2
be isolated in 67% yield by treating 1a with Cu(OAc) ·H O. The use of 3a
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1
1
1
1
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1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
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4
4
4
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6
instead of 1a to react with C60 under the optimized conditions proceeded well,
and afforded the desired product 2a in 32% yield, which was nearly the same as
that for the reaction of C60 with 1a. This result indicated that 3a should be the
intermediate for the heteroannulation reaction.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
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7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Scheme 1. Control Experiments
Based on the above results and previous reports on the copperꢀpromoted radical
reactions, a plausible mechanism for the formation of 2ꢀfulleropyrrolines 2a–m is
proposed and depicted in Scheme 2. This transformation is initiated via oxidation of 1
II
by Cu to afford the imine intermediate 3. Tautomerization of the imine intermediate 3
1
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gives the enamine 4, which can be transformed to the imino radical A through
II
homolysis of the N–Cu bond of the formed Cu complex. The fullerenyl radical B can
be produced after capture of the imino radical A by C60, and then undergoes
cyclization to generate radical C. Subsequently, the radical C is converted to 2 by
10
11
12
13
14
15
16
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22
23
24
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34
35
36
37
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41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
II
oxidation with a Cu species accompanied by proton elimination (path a).
Alternatively, tautomerization of A can also give D, which attacks C60 to afford
fullerenyl radical E. The cyclization of E generates the same radical C (path b).
Scheme 2. Proposed Reaction Mechanism for the Formation of 2
1
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2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
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4
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0
1
2
3
4
5
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7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
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7
8
9
0
1
2
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9
0
1
2
3
4
5
6
7
8
9
0
To determine the preferred reaction pathway towards the formation of the radical
C, computational study for the reaction of C60 with 1a at the UB3LYP/6ꢀ31G (d) level
1
0
with the Gaussian 09 program was performed, and the energy profiles are depicted
in Scheme 3. Although the energy of the radical intermediate Aꢀ1a is the same as that
of Dꢀ1a, the formation of the fullerenyl radical Bꢀ1a requires an activation energy of
1
9.6 kcal/mol, 12.2 kcal/mol higher than that for the formation of Eꢀ1a. Furthermore,
the fullerenyl radical Eꢀ1a is more stable than Bꢀ1a by 16.8 kcal/mol. Therefore, the
product formation via Dꢀ1a should be more favorable (path b) even though the
activation energy required to produce Cꢀ1a from Eꢀ1a is a little higher than that from
1
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Bꢀ1a.
Scheme 3. Computational Results at the UB3LYP/6ꢀ31G (d) Level
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
The halfꢀwave reduction potentials of products 2a–m along with those of C60
have been investigated by cyclic voltammetry (CV), and their halfꢀwave potentials are
summarized in Table 3. All of their electrochemical properties were quite similar and
showed two reversible redox processes. As shown in Table 3, the first reduction
potentials of 2ꢀfulleropyrrolines 2a–m were more negative than that of C , indicating
60
that they possess higher LUMO energy levels than that of C60 and may have potential
11
application in organic photovoltaic devices by utilizing appropriate donor acceptors.
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1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
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5
5
5
5
5
5
6
a
Table 3. HalfꢀWave Reduction Potentials of 2a–m and C60
compound
E1
E2
C
60
–1.080
–1.130
–1.128
–1.128
–1.132
–1.135
–1.124
–1.141
–1.130
–1.146
–1.137
–1.144
–1.098
–1.123
–1.473
–1.510
–1.517
–1.517
–1.515
–1.522
–1.530
–1.527
–1.503
–1.531
–1.522
–1.534
–1.474
–1.513
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
2
a
2b
2
c
2d
2
e
2f
2
g
2h
2
i
b
2j
2
k
2l
2
m
a
Versus ferrocene/ferrocenium. Experimental conditions: 1 mM of 2a–m/C60 and 0.1
M of ꢀBu NClO in anhydrous ODCB; reference electrode: SCE; working electrode:
n
4
4
ꢀ1 b
Pt; auxiliary electrode: Pt wire; scanning rate: 20 mV s . Saturated solution.
CONCLUSIONS
2
In summary, we have successfully disclosed a Cu(OAc) ꢀpromoted heteroannulation
1
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reaction of [60]fullerene with
αꢀamino ketones for the efficient construction of a
series of 2ꢀfullereropyrrolines containing a trisubstituted or tetrasubstituted C=C bond
via the formation of C–C and C–N bonds. Control experiments and theoretical
calculations revealed that the process via the attack of the carbon radical species
10
11
12
13
14
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32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
generated from the employed αꢀamino ketone to [60]fullerene should be a preferred
pathway for the formation of 2ꢀfulleropyrrolines. The electrochemistry of the
synthesized 2ꢀfulleropyrrolines has also been explored.
EXPERIMENTAL SECTION
General Procedure for the Synthesis of 2a–m from the
Cu(OAc)
2
·H
2
OꢀPromoted Reaction of C60 with 1a–m. A mixture of C60 (0.05
mmol),
αꢀamino ketones 1 (0.10 mmol), and Cu(OAc)
2
·H
2
O (0.10 mmol) was
o
dissolved in CB (6 mL). Then the solution was vigorously stirred at 130 C and
stopped at the designated time. The solvent was evaporated in vacuo and the residue
2 2 2
was directly separated on a silica gel column with CS /CH Cl (10:1 v/v unless
specified) as the eluent to give recovered C60 and then the desired product 2. Cautions:
in order to avoid the decomposition of 2 induced by light, the used glasswares should
be wrapped with aluminum foil during the workup procedure including separation on
a silica gel column and subsequent evaporation in vacuo.
Fulleropyrroline 2a. By following the general procedure, the reaction of C60
2 2
(35.9 mg, 0.05 mmol) with 1a (22.2 mg, 0.10 mmol) and Cu(OAc) ·H O (19.7 mg,
o
0
.10 mmol) at 130 C for 5 h afforded recovered C60 (20.8 mg, 58%) and 2a (15.7 mg,
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2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
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4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
1
3
4%): amorphous brown solid; H NMR (400 MHz, CS
2
/CDCl
3
(3:1 v/v))
δ
J
8.27 (d,
J
=
7.3 Hz, 2H), 7.61 (t,
H), 7.28 (t, = 7.8 Hz, 2H), 7.14 (t,
MHz, CS /CDCl (3:1 v/v)) 187.3, 149.1, 147.8, 147.3, 146.11, 146.05, 145.9, 145.8,
J
= 7.4 Hz, 1H), 7.56 (d,
J
= 8.0 Hz, 4H), 7.52 (t,
= 7.6 Hz,
13
2
J
J = 7.4 Hz, 1H), 6.56 (s, 1H); C NMR (100
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
δ
2
3
1
1
1
2
45.7, 145.3, 145.1, 145.0, 144.8, 144.6, 144.4, 144.1, 143.4, 143.0, 142.64, 142.57,
42.5, 142.12, 142.10, 141.8, 140.6, 139.5, 136.8, 136.2, 135.9, 133.4, 129.6, 129.5,
3
3
ꢀ1
28.5, 127.9, 126.6, 114.7, 90.1 (sp ꢀ
C of C60), 75.0 (sp ꢀC of C60); FTꢀIR ν/cm (KBr)
921, 2854, 1658, 1592, 1491, 1432, 1369, 1225, 1173, 1004, 696, 565, 524; UVꢀvis
(CHCl ) λmax/nm (log
ε
) 257 (5.02), 323 (4.47), 428 (3.46); HRMS (ESIꢀFTꢀICR) m/z
3
+
calcd for C75
H
12NO [M+H] 942.0913, found 942.0902.
Fulleropyrroline 2b. By following the general procedure, the reaction of C60
(
2 2
35.9 mg, 0.05 mmol) with 1b (23.5 mg, 0.10 mmol) and Cu(OAc) ·H O (19.8 mg,
o
0.10 mmol) at 130 C for 5 h afforded recovered C60 (19.4 mg, 54%) and 2b (16.0 mg,
1
3
4%): amorphous brown solid; H NMR (400 MHz, CS /CDCl (3:1 v/v))
δ
8.22–
2
3
8.15 (m, 2H), 7.64–7.58 (m, 2H), 7.56–7.49 (m, 2H), 7.21–7.10 (m, 3H), 6.40 (s, 1H),
13
2
.66 (s, 3H); C NMR (100 MHz, CS
2
/CDCl
3
(3:1 v/v))
δ
186.8, 149.6, 149.1, 148.5,
147.7, 147.3, 146.08, 146.05, 145.9, 145.82, 145.78, 145.61, 145.55, 145.2, 145.13,
45.11, 145.07, 145.03, 145.01, 144.98, 144.7, 144.4, 144.33, 144.31, 144.11, 144.08,
143.0, 142.61, 142.59, 142.56, 142.15, 142.13, 142.11, 142.10, 142.06, 142.0, 141.8,
41.7, 140.8, 140.6, 139.6, 139.4, 138.3, 137.1, 135.9, 135.8, 133.1, 131.8, 131.0,
1
1
3
3
129.6, 128.4, 127.9, 126.9, 112.4, 90.5 (sp ꢀC of C60), 75.0 (sp ꢀC of C60), 19.8; FTꢀIR
ꢀ1
ν
/cm (KBr) 2918, 2854, 1661, 1600, 1508, 1435, 1379, 1271, 1231, 1175, 1110,
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1
052, 1011, 902, 806, 706, 524; UVꢀvis (CHCl
3
) λmax/nm (log
ε
) 257 (5.15), 318
+
(4.61), 428 (3.57); HRMS (ESIꢀFTꢀICR)
m
/z
calcd for C76
H
14NO [M+H] 956.1070,
found 956.1057.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
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40
41
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43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Fulleropyrroline 2c. By following the general procedure, the reaction of C60
(
2 2
35.9 mg, 0.05 mmol) with 1c (23.7 mg, 0.10 mmol) and Cu(OAc) ·H O (19.9 mg,
o
0
3
8
2
1
.10 mmol) at 130 C for 5 h afforded recovered C60 (20.6 mg, 57%) and 2c (15.8 mg,
1
3%): amorphous brown solid; H NMR (400 MHz, CS
2 3
/CDCl (3:1 v/v)) δ 8.22–
.17 (m, 2H), 7.65–7.59 (m, 2H), 7.56–7.49 (m, 2H), 7.21–7.10 (m, 3H), 6.41 (s, 1H),
13
.66 (s, 3H); C NMR (100 MHz, CS /CDCl (3:1 v/v))
δ
186.9, 149.5, 149.1, 148.4,
2
3
47.7, 147.3, 146.1, 146.0, 145.9, 145.79, 145.75, 145.6, 145.5, 145.14, 145.10,
145.06, 145.01, 144.99, 144.96, 144.7, 144.4, 144.30, 144.29, 144.08, 144.06, 142.96,
42.93, 142.59, 142.56, 142.5, 142.12, 142.11, 142.08, 142.03, 142.02, 141.74,
141.71, 140.8, 140.6, 139.5, 139.4, 138.2, 137.1, 135.9, 135.8, 133.2, 131.8, 130.9,
1
3
3
ꢀ1
1
29.6, 128.4, 127.9, 112.6, 90.5 (sp ꢀ
C of C ), 75.0 (sp ꢀC of C ), 19.8; FTꢀIR ν/cm
60 60
(KBr) 2919, 1657, 1593, 1491, 1434, 1371, 1263, 1227, 1174, 1109, 1049, 1005, 706,
5
65, 525; UVꢀvis (CHCl
3
) λmax/nm (log
ε) 258 (5.09), 327 (4.53), 428 (3.52); HRMS
+
(MALDIꢀTOF) calcd for C76
m
/
z
H
13NO [M] 955.0992, found 955.0979.
Fulleropyrroline 2d. By following the general procedure, the reaction of C60
(35.9 mg, 0.05 mmol) with 1d (23.8 mg, 0.10 mmol) and Cu(OAc) ·H O (19.9 mg,
2
2
o
0
.10 mmol) at 130 C for 5 h afforded recovered C60 (22.7 mg, 63%) and 2d (14.8 mg,
1
31%): amorphous brown solid; H NMR (400 MHz, CS
2
/CDCl
3
(3:1 v/v))
δ 7.61–
7
.55 (m, 2H), 7.58 (tt,
J
= 7.4, 1.3 Hz, 1H), 7.42–7.37 (m, 2H), 7.40 (d,
J
= 8.2 Hz,
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2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
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4
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5
5
5
5
5
5
5
6
1
3
2
H), 7.04 (d,
J
= 8.2 Hz, 2H), 6.47 (s, 1H), 2.27 (s, 3H); C NMR (100 MHz,
CS /CDCl (3:1 v/v)) δ
2
3
187.0, 149.1, 147.9, 147.7, 147.2, 146.1, 146.0, 145.9, 145.81,
1
1
1
2
7
45.77, 145.6, 145.4, 145.1, 145.0, 144.8, 144.7, 144.3, 144.1, 142.9, 142.6, 142.5,
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
42.1, 141.7, 140.8, 140.6, 139.4, 136.7, 136.3, 136.1, 135.8, 133.2, 130.1, 129.5,
3
3
ꢀ1
28.4, 127.9, 113.7, 90.2 (sp ꢀ
C of C60), 74.9 (sp ꢀC of C60), 21.2; FTꢀIR ν/cm (KBr)
918, 2857, 1661, 1599, 1510, 1428, 1378, 1270, 1232, 1175, 1110, 1009, 904, 807,
09, 570, 525; UVꢀvis (CHCl
3
) λmax/nm (log
ε
) 257 (5.06), 325 (4.49), 428 (3.48);
+
HRMS (ESIꢀFTꢀICR)
m
/z
calcd for C76
H
14NO [M+H] 956.1070, found 956.1054.
Fulleropyrroline 2e. By following the general procedure, the reaction of C60
(
2 2
36.1 mg, 0.05 mmol) with 1e (23.0 mg, 0.10 mmol) and Cu(OAc) ·H O (19.6 mg,
o
0.10 mmol) at 130 C for 3 h afforded recovered C60 (17.4 mg, 48%) and 2e (16.5 mg,
3
4%) with CS
2
/CH
2
Cl
2
(5:1, v/v) as the eluent for silica gel column purification:
1
amorphous brown solid; H NMR (400 MHz, CS
2
/CDCl
3
(3:1 v/v))
δ
8.28 (d,
= 8.8 Hz, 2H),
= 8.8 Hz, 2H), 6.50 (s, 1H), 3.72 (s, 3H); C NMR (100 MHz, CS /CDCl
187.3, 158.0, 149.2, 148.0, 147.7, 147.2, 146.1, 146.0, 145.9, 145.8, 145.6,
145.3, 145.1, 145.0, 144.9, 144.8, 144.3, 144.1, 142.9, 142.6, 142.5, 142.10, 142.07,
41.7, 140.6, 139.5, 136.8, 136.1, 136.0, 135.8, 133.3, 129.52, 129.47, 128.4, 114.6,
J = 7.2
Hz, 2H), 7.62 (t,
6.79 (d,
3:1 v/v))
J
= 7.3 Hz, 1H), 7.53 (t,
J
= 7.6 Hz, 2H), 7.48 (d, J
13
J
2
3
(
δ
1
3
3
ꢀ1
113.0, 90.4 (sp ꢀ
C of C ), 74.8 (sp ꢀC of C ), 54.9; FTꢀIR ν/cm (KBr) 2922, 2834,
60 60
1
658, 1600, 1504, 1434, 1369, 1240, 1171, 1103, 1032, 1002, 702, 565, 523; UVꢀvis
(CHCl
3
) λmax/nm (log
ε
) 256 (5.06), 326 (4.49), 428 (3.48); HRMS (MALDIꢀTOF)
+
m
/z
calcd for C76
H13NO
2
[M] 971.0941, found 971.0927.
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Fulleropyrroline 2f. By following the general procedure, the reaction of C60
(
2 2
36.0 mg, 0.05 mmol) with 1f (25.6 mg, 0.10 mmol) and Cu(OAc) ·H O (20.2 mg,
o
0
3
.10 mmol) at 130 C for 5 h afforded recovered C60 (17.8 mg, 49%) and 2f (14.9 mg,
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
1
1%): amorphous brown solid; H NMR (400 MHz, CS with DMSOꢀd6 as the
2
external reference)
H), 7.43 (d, = 8.7 Hz, 2H), 7.19 (d,
MHz, CS /CDCl (3:1 v/v)) 186.6, 148.7, 147.7, 147.19, 147.17, 146.03, 145.96,
45.8, 145.74, 145.66, 145.6, 145.1, 145.0, 144.7, 144.24, 144.21, 144.0, 142.6, 142.5,
42.4, 142.0, 141.9, 141.8, 141.68, 141.65, 140.6, 139.5, 136.6, 136.2, 135.7, 133.3,
δ
8.21–8.16 (m, 2H), 7.58 (tt,
J = 7.3, 1.3 Hz, 1H), 7.51–7.46 (m,
13
2
J
J
= 8.7 Hz, 2H), 6.49 (s, 1H); C NMR (100
2
3
δ
1
1
3
3
1
32.6, 129.5, 129.4, 129.0, 128.5, 115.1, 89.8 (sp ꢀ
C
of C60), 74.9 (sp ꢀ
/cm (KBr) 2919, 1654, 1497, 1435, 1374, 1229, 1171, 1092, 1010, 702, 522;
) λmax/nm (log ) 258 (5.14), 328 (4.60), 429 (3.51); HRMS
calcd for C75
Fulleropyrroline 2g. By following the general procedure, the reaction of C60
C of C60);
ꢀ1
FTꢀIR
ν
UVꢀvis (CHCl
3
ε
3
5
+
(ESIꢀFTꢀICR)
m/
z
H11NO Cl [M+H] 976.0524, found 976.0525.
2 2
(35.9 mg, 0.05 mmol) with 1g (25.6 mg, 0.10 mmol) and Cu(OAc) ·H O (20.0 mg,
o
0
.10 mmol) at 130 C for 3 h afforded recovered C60 (18.1 mg, 50%) and 2g (19.4 mg,
1
40%): amorphous brown solid; H NMR (400 MHz, CS
.24 (m, 2H), 7.61 (tt, = 7.3, 1.3 Hz, 1H), 7.56–7.49 (m, 2H), 7.16 (s, 2H), 6.75 (s,
1H), 6.50 (s, 1H), 2.22 (s, 6H); C NMR (100 MHz, CS /CDCl (3:1 v/v))
2 3
/CDCl (3:1 v/v)) δ 8.31–
8
J
13
δ
187.7,
49.3, 148.1, 147.8, 147.3, 146.2, 146.1, 146.0, 145.93, 145.88, 145.7, 145.5, 145.2,
145.12, 145.09, 144.9, 144.8, 144.4, 144.2, 143.3, 143.0, 142.7, 142.63, 142.60,
42.22, 142.20, 141.83, 141.80, 140.7, 139.5, 139.0, 136.9, 136.2, 135.9, 133.4, 129.6,
2
3
1
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3
ꢀ1
1
28.6, 128.5, 125.7, 114.3, 90.2 (sp ꢀ
C of C60), 75.1 (sp ꢀC of C60), 21.4; FTꢀIR ν/cm
(
KBr) 2914, 2855, 1660, 1593, 1512, 1434, 1375, 1244, 1170, 1107, 1047, 1005, 904,
7
32, 564, 525; UVꢀvis (CHCl
3
) λmax/nm (log
ε
) 257 (5.05), 324 (4.53), 428 (3.50);
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
+
HRMS (ESIꢀFTꢀICR)
m
/z
calcd for C H NO [M+H] 970.1226, found 970.1211.
77
16
Fulleropyrroline 2h. By following the general procedure, the reaction of C60
(
2 2
35.9 mg, 0.05 mmol) with 1h (26.6 mg, 0.10 mmol) and Cu(OAc) ·H O (19.7 mg,
o
0
.10 mmol) at 130 C for 3 h afforded recovered C60 (17.1 mg, 48%) and 2h (18.0 mg,
1
3
7%): amorphous brown solid; H NMR (400 MHz, CS
2
/CDCl
= 8.1 Hz, 2H), 7.14 (s, 2H), 6.73 (s, 1H), 6.45 (s, 1H), 2.47
/CDCl (3:1 v/v)) 186.6, 149.2, 148.0,
3
(3:1 v/v)) δ 8.18 (d, J
=
8.1 Hz, 2H), 7.31 (d, J
13
(
s, 3H), 2.22 (s, 6H); C NMR (100 MHz, CS
2
3
δ
147.7, 147.2, 146.05, 145.98, 145.85, 145.82, 145.7, 145.6, 145.4, 145.04, 144.97,
44.8, 144.7, 144.3, 144.04, 143.96, 143.2, 142.9, 142.6, 142.5, 142.1, 141.71, 141.67,
140.6, 139.3, 138.8, 136.1, 135.8, 134.3, 129.8, 129.1, 128.4, 125.6, 113.2, 90.0
1
3
3
ꢀ1
(sp ꢀ
C of C ), 75.0 (sp ꢀC of C ), 21.9, 21.4; FTꢀIR ν/cm (KBr) 2915, 2858, 1662,
60 60
1601, 1513, 1462, 1428, 1346, 1304, 1258, 1172, 1109, 1042, 1002, 841, 783, 729,
5
64, 526; UVꢀvis (CHCl
3
) λmax/nm (log
ε
) 257 (5.15), 328 (4.64), 428 (3.61); HRMS
+
(ESIꢀFTꢀICR) calcd for C78
m/
z
H
18NO [M+H] 984.1383, found 984.1360.
Fulleropyrroline 2i. By following the general procedure, the reaction of C60 (36.0
mg, 0.05 mmol) with 1i (28.6 mg, 0.15 mmol) and Cu(OAc) ·H O (30.3 mg, 0.15
2
2
o
mmol) at 130 C for 3 h afforded recovered C60 (15.9 mg, 44%) and 2i (7.7 mg, 17%):
1
amorphous brown solid; H NMR (400 MHz, CS
2
/CDCl
3
(3:1 v/v))
δ
8.36–8.28 (m,
= 6.9
2
H), 7.68 (t,
J
= 7.3 Hz, 1H), 7.59 (t,
J
= 7.5 Hz, 2H), 5.90 (s, 1H), 4.79 (hept, J
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Hz, 1H), 1.61 (d,
J
= 6.9 Hz, 6H); C NMR (100 MHz, CS
2 3
/CDCl (3:1 v/v)) δ 189.6,
1
1
1
8
2
49.9, 148.4, 147.8, 147.3, 146.2, 146.01, 145.98, 145.9, 145.8, 145.7, 145.1, 145.02,
44.99, 144.9, 144.5, 144.1, 143.7, 143.1, 142.68, 142.66, 142.6, 142.4, 142.14,
42.13, 141.80, 141.79, 140.7, 139.6, 137.4, 136.4, 135.6, 133.6, 130.1, 128.6, 108.9,
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44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
3
3
ꢀ1
9.9 (sp ꢀ
C of C60), 75.1 (sp ꢀC of C60), 50.3, 22.8; FTꢀIR ν/cm (KBr) 2964, 2923,
861, 1665, 1595, 1510, 1433, 1378, 1315, 1242, 1181, 1107, 994, 710, 565, 525;
UVꢀvis (CHCl
3
) λmax/nm (log
calcd for C72
ε) 257 (5.13), 324 (4.54), 428 (3.68); HRMS
+
(ESIꢀFTꢀICR)
m
/
z
H
14NO [M+H] 908.1070, found 908.1049.
Fulleropyrroline 2j. By following the general procedure, the reaction of C (35.9
60
2 2
mg, 0.05 mmol) with 1j (35.9 mg, 0.15 mmol) and Cu(OAc) ·H O (30.1 mg, 0.15
o
mmol) at 130 C for 3 h afforded recovered C60 (22.3 mg, 62%) and 2j (8.6 mg, 18%):
1
amorphous brown solid; H NMR (400 MHz, CS
2
with DMSOꢀ
d
6
as the external
reference)
δ 8.23 (d, J = 7.8 Hz, 2H), 7.58–7.44 (m, 3H), 7.44–7.35 (m, 2H), 7.22–
7
.12 (m, 2H), 7.06–6.98 (m, 1H), 2.54 (s, 3H); (It should be noted that the very low
13
solubility of 2j prevented us from obtaining a C NMR spectrum with a good
ꢀ1
signalꢀtoꢀnoise ratio); FTꢀIR
ν
/cm (KBr) 2926, 2863, 1660, 1631, 1593, 1510, 1488,
1448, 1430, 1342, 1300, 1221, 1176, 1106, 988, 746, 732, 711, 694, 576, 526; UVꢀvis
(CHCl
3
) λmax/nm (log
ε
) 256 (5.05), 326 (4.49), 428 (3.50); HRMS (MALDIꢀTOF)
+
m
/z
calcd for C H NO [M] 955.0992, found 955.0981.
7
6
13
Fulleropyrroline 2k. By following the general procedure, the reaction of C60
2 2
(36.0 mg, 0.05 mmol) with 1k (39.5 mg, 0.15 mmol) and Cu(OAc) ·H O (29.8 mg,
o
0
.15 mmol) at 130 C for 3 h afforded recovered C60 (18.8 mg, 52%) and 2k (10.8 mg,
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5
5
5
5
5
5
5
5
6
1
2
8
6
2%): amorphous brown solid; H NMR (400 MHz, CS
2
/CDCl
3
(3:1 v/v))
δ
8.28–
.23 (m, 2H), 7.50 (tt,
.63–6.60 (m, 1H), 6.61 (s, 1H), 2.52 (s, 3H), 2.15 (s, 6H); C NMR (100 MHz,
189.0, 148.8, 147.8, 147.3, 147.2, 146.08, 146.06, 145.9,
J = 7.3, 1.3 Hz, 1H), 7.44–7.38 (m, 2H), 7.10–7.07 (m, 2H),
13
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
CS /CDCl (3:1 v/v))
δ
2
3
1
1
1
45.8, 145.7, 145.6, 145.5, 145.35, 145.28, 145.0, 144.9, 144.3, 144.2, 143.8, 142.9,
42.6, 142.5, 142.3, 142.14, 142.11, 142.06, 141.8, 141.6, 140.4, 139.3, 138.7, 136.6,
3
35.94, 135.88, 133.0, 129.4, 128.2, 128.1, 125.80, 118.8, 88.6 (sp ꢀ
C of C60), 76.8
3
ꢀ1
(
sp ꢀC of C60), 21.3, 12.7; FTꢀIR ν/cm (KBr) 2921, 2858, 1646, 1593, 1507, 1437,
1
339, 1229, 1170, 1052, 994, 700, 617, 563, 523; UVꢀvis (CHCl ) λmax/nm (log
ε
) 258
3
+
(
5.03), 326 (4.42), 428 (3.40); HRMS (ESIꢀFTꢀICR)
m
/z
calcd for C78H18NO [M+H]
984.1383, found 984.1384.
Fulleropyrroline 2l. By following the general procedure, the reaction of C60 (36.1
2 2
mg, 0.05 mmol) with 1l (45.0 mg, 0.15 mmol) and Cu(OAc) ·H O (30.1 mg, 0.15
o
mmol) at 130 C for 3 h afforded recovered C60 (16.9 mg, 47%) and 2l (20.6 mg,
1
40%): amorphous brown solid; H NMR (400 MHz, CS
2
with DMSOꢀ
= 8.2 Hz, 2H), 7.52 (d,
= 7.5 Hz, 2H), 7.27–7.15 (m, 5H), 7.10
with DMSOꢀ as the external reference)
6
d as the
external reference)
δ
8.19 (d,
J
= 7.5 Hz, 2H), 7.56 (d,
J
J =
6.6 Hz, 2H), 7.48 (t,
J
= 7.3 Hz, 1H), 7.39 (t,
J
13
(t,
J
= 7.4 Hz, 1H); C NMR (100 MHz, CS
2
d
6
δ
187.3, 148.2, 147.2, 146.7, 145.6, 145.5, 145.4, 145.33, 145.32, 145.29, 145.12,
45.08, 144.7, 144.6, 144.4, 143.8, 143.6, 142.7, 142.4, 142.11, 142.06, 141.8, 141.7,
1
141.64, 141.60, 141.3, 141.1, 139.6, 139.0, 135.7, 135.0, 132.8, 131.9, 130.4, 128.9,
3
3
1
28.4, 127.9, 127.8, 127.4, 126.3, 119.6, 89.0 (sp ꢀC of C60), 78.2 (sp ꢀC of C60);
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ꢀ
1
FTꢀIR
ν
/cm (KBr) 2922, 2849, 1669, 1649, 1593, 1578, 1512, 1492, 1447, 1429,
347, 1227, 1003, 766, 755, 744, 733, 698, 562, 527; UVꢀvis (CHCl ) λmax/nm (log
calcd for C81 15NO
1
2
3
ε)
56 (5.06), 313 (4.53), 426 (3.51); HRMS (MALDIꢀTOF)
m
/z
H
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
+
[
M] 1017.1148, found 1017.1136.
Fulleropyrroline 2m. By following the general procedure, the reaction of C60
(
2 2
36.1 mg, 0.05 mmol) with 1m (49.3 mg, 0.15 mmol) and Cu(OAc) ·H O (29.5 mg,
o
0
.15 mmol) at 130 C for 3 h afforded recovered C60 (16.3 mg, 45%) and 2m (22.5
1
mg, 43%): amorphous brown solid; H NMR (400 MHz, CS
external reference) 8.25–8.16 (m, 2H), 7.54–7.44 (m, 3H), 7.39 (t,
.23–7.12 (m, 5H), 6.70 (s, 1H), 2.20 (s, 6H); C NMR (100 MHz, CS
DMSOꢀ as the external reference) 187.3, 148.2, 147.1, 146.6, 145.53, 145.47,
45.32, 145.29, 145.26, 145.22, 145.17, 145.0, 144.7, 144.5, 144.4, 143.8, 143.5,
142.9, 142.3, 142.05, 141.99, 141.8, 141.58, 141.55, 141.54, 141.3, 141.0, 139.6,
38.8, 138.2, 135.7, 135.5, 135.0, 132.6, 132.0, 130.3, 128.9, 128.1, 127.74, 127.69,
2
with DMSOꢀ
= 7.5 Hz, 2H),
with
6
d as the
δ
J
13
7
2
d
6
δ
1
1
3
3
ꢀ1
127.3, 126.2, 118.9, 89.0 (sp ꢀ
C of C60), 78.2 (sp ꢀC of C60), 20.8; FTꢀIR ν/cm (KBr)
2
911, 1667, 1593, 1511, 1447, 1327, 1221, 1165, 1005, 851, 831, 695, 563, 527;
UVꢀvis (CHCl
3
) λmax/nm (log
calcd for C83
ε
) 257 (5.07), 314 (4.54), 428 (3.55); HRMS
+
(
MALDIꢀTOF)
m
/
z
H
19NO [M] 1045.1461, found 1045.1445.
1ꢀPhenylꢀ2ꢀ(phenylimino)propanꢀ1ꢀone 3a. A mixture of 1a (22.4 mg, 0.10 mmol)
o
and Cu(OAc)
2
·H
2
O (19.7 mg, 0.10 mmol) in CB (3mL) was heated at 130 C for 3 h.
The reaction mixture was cooled to room temperature and most of the solvent was
evaporated in vacuo. The residue was purified by column chromatography (SiO
2
,
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2
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2
1
PE/EtOAc = 30:1) to afford 3a as colorless oil (14.9 mg, 67%); H NMR (400 MHz,
CDCl 8.14 (d, = 7.8 Hz, 2H), 7.59 (t, = 7.4 Hz, 1H), 7.48 (t, = 7.6 Hz, 2H),
.39 (t, = 7.8 Hz, 2H), 7.15 (t, = 7.4 Hz, 1H), 6.86 (d, = 7.8 Hz, 2H), 2.17 (s, 3H).
Previous literature data for 3a: H NMR (300 MHz, CDCl ) 8.15 (dd, = 8.4, 1.5
= 8.4, 7.5 Hz, 2H), 7.39 (dd, = 8.4,
= 7.2, 1.2 Hz, 1H), 6.86 (dd, = 8.4, 1.2 Hz, 2H), 2.18 (s,
3
)
δ
J
J
J
7
J
J
J
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
δ
J
3
Hz, 2H), 7.60 (tt,
J
= 7.5, 1.5 Hz, 1H), 7.48 (dd,
J
J
7
3
.2 Hz, 2H), 7.16 (tt,
J
J
1
2
H).
ASSOCIATED CONTENT
Supporting Information
NMR spectra of 2a–m and 3a, CVs of 2a–m, and computational results. This material
is available free of charge via the Internet at http;//pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author:
*
Email: gwang@ustc.edu.cn
Notes
The authors declare no competing financial interest.
ACKNOWLEDGEMENTS
We are grateful for financial support from the National Natural Science
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Foundation of China (No. 21572211, 21132007).
REFERENCES
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11
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42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
(
1) For reviews, see: (a) Nakamura, E.; Isobe, H. Acc. Chem. Res. 2003, 36, 807. (b)
Thilgen, C.; Diederich, F. Chem. Rev. 2006, 106, 5049. (c) Giacalone, F.; Martín,
N. Chem. Rev. 2006, 106, 5136. (d) Matsuo, Y.; Nakamura, E. Chem. Rev. 2008,
108, 3016. (e) Guldi, D. M.; Illescas, B. M.; Atienza, C. M.; Wielopolski, M.;
Martín, N. Chem. Soc. Rev. 2009, 38, 1587. (f) Li, C.ꢀZ.; Yip, H.ꢀL.; Jen, A. K.ꢀY.
J. Mater. Chem. 2012, 22, 4161. (g) Zhu, S.ꢀE; Li, F.; Wang, G.ꢀW. Chem. Soc.
Rev. 2013, 42, 7535.
(2) For reviews, see: (a) Morton, J. R.; Negri, F.; Preston, K. F. Acc. Chem. Res. 1998,
, 63. (b) Wang, G.ꢀW.; Li, F.ꢀB. J. Nanosci. Nanotechnol. 2007, , 1162. (c)
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7
Wang, G.ꢀW.; Li, F.ꢀB. Curr. Org. Chem. 2012, 16, 1109. (d) Li, F.; Wang, G. Sci.
China Chem. 2012, 55, 2009. (e)Tzirakis, M. D.; Orfanopoulos, M. Chem. Rev.
2013, 113, 5262.
(3) For selected examples, see: (a) Zhang, T.ꢀH.; Lu, P.; Wang, F.; Wang, G.ꢀW. Org.
Biomol. Chem. 2003,
1, 4403. (b) Wang, G.ꢀW.; Yang, H.ꢀT.; Miao, C.ꢀB.; Xu, Y.;
Liu, F. Org. Biomol. Chem. 2006,
4, 2595. (c) Wang, G.ꢀW.; Wang, C.ꢀZ.; Zou,
J.ꢀP. J. Org. Chem. 2011, 76, 6088 and references cited therein.
(4) For selected examples, see: (a) Li, F.ꢀB.; Liu, T.ꢀX.; Wang, G.ꢀW. J. Org. Chem.
2008, 73, 6417. (b) Liu, T.ꢀX.; Li, F.ꢀB.; Zhou, D.ꢀB.; Wang, G.ꢀW. J. Org. Chem.
2
015, 80, 11986 and references cited therein.
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