Preparation of 3,4,5-trisubstituted oxazolones by pd-catalyzed coupling of n -alkynyl tert -butyloxycarbamates with aryl halides and related electrophiles

Article abstract of DOI:10.1021/jo301794w

A novel palladium-catalyzed approach for the assembly of 3,4,5-trisubstituted oxazolones has been achieved by the coupling of N-alkynyl tert-butyloxycarbamates with aryl halides and related electrophiles, which involves an oxidative addition followed by oxypalladation/reductive elimination. The reaction provides a convenient access to diversely substituted oxazolones in satisfactory yields and shows good functional group compatibility.

Full text of DOI:10.1021/jo301794w

Note
pubs.acs.org/joc
Preparation of 3,4,5-Trisubstituted Oxazolones by Pd-Catalyzed
Coupling of N‑Alkynyl tert-Butyloxycarbamates with Aryl Halides and
Related Electrophiles
Zenghui Lu, Weijian Cui, Siyuan Xia, Yihui Bai, Fang Luo, and Gangguo Zhu*
Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua 321004, China
S
* Supporting Information
ABSTRACT: A novel palladium-catalyzed approach for the
assembly of 3,4,5-trisubstituted oxazolones has been achieved
by the coupling of N-alkynyl tert-butyloxycarbamates with aryl
halides and related electrophiles, which involves an oxidative
addition followed by oxypalladation/reductive elimination.
The reaction provides a convenient access to diversely
substituted oxazolones in satisfactory yields and shows good
functional group compatibility.
xazolones occur in a number of natural products and
starting material 1a, probably due to the low solubility of
Opharmacological active compounds and have attracted K2CO3 in these solvents (Table 1, entries 5−10). The omission
of PPh3 ligand resulted in low conversion (Table 1, entry 11).
Interestingly, the ligand evaluation (Table 1, entries 12−18)
revealed that the readily accessible PPh3 was the most effective
ligand for this transformation, thus making this reaction rather
practical and attractive for the synthetic community. Other
palladium sources such as Pd(OAc)2 and Pd(PPh3)4 could also
promote the reaction, albeit in relative lower yields (Table 1,
entries 19 and 20, respectively). Therefore, 5 mol % of
Pd(dba)2, 10 mol % of PPh3, and 1.5 equiv of K2CO3 in DMF
at 70 °C were chosen as the best conditions for the Pd-
catalyzed coupling of N-alkynyl tert-butyloxycarbamates with
aromatic iodides.
The optimized reaction conditions appeared to be
remarkably general. As shown in Table 2, a wide range of
aryl iodides coupled smoothly with 1a to provide 3,4,5-
trisubstituted oxazolones in moderate to excellent yields (Table
2, entries 1−9). For instance, 1-bromo-4-iodobenzene (2e) and
4-iodobenzaldehyde (2f) formed the desired products 8 and 9
in 90 and 81% yield, respectively (Table 2, entries 5 and 6).
The X-ray analysis of 10 clearly demonstrated the structure of
3,4,5-trisubstituted oxazolone products.
In addition, the more accessible aryl bromides proved to be
competent substrates for this reaction, giving rise to 3,4,5-
trisubstituted oxazolones in good yields, albeit at an elevated
reaction temperature (Table 2, entries 10−25). Various
functional groups, such as F, Cl, Br, OMe, CO2Et, CHO,
COCH3, and CN, turned out to be well tolerated under the
optimized conditions. For example, 4-chloroiodobenzene (3d)
generated 7 in 80% yield, while 2-chloroiodobenzene (3e) gave
rise to 13 in 82% yield (Table 2, entries 13 and 14), indicating
that yield remained high independent of where the chlorine
extensive interest in organic chemistry. For example,
oxazolones are known to be versatile starting materials for
the cycloaddition reaction,1−3 radical reaction,4,5 and assembly
of synthetic useful functionalized heterocycles.6,7 However,
there are only limited methods for the effective synthesis of
multisubstituted oxazolones.8−13 A powerful method for the
production of 3,5-disubstituted oxazolones featuring a Au-
catalyzed cyclization of N-alkynyl tert-butyloxycarbamates has
been developed by Hashmi14 and Gagosz,15 independently. In
2008, Jiang and co-workers reported an efficient approach to
oxazolones from propargylic alcohols and carbon dioxide under
supercritical conditions.16 More recently, the Lautens group
described an elegant synthesis of 3,5-disubstituted oxazolones
using a Pd-catalyzed transformation of β,β-dibromoenamides.17
Despite the success of these methods, an effective and general
synthesis of 3,4,5-trisubstituted oxazolones from readily
available starting materials constitutes a demanding goal.
Given our continuing interest in the Pd-catalyzed functionaliza-
tion of heteroatom-substituted acetylenes,18−25 we describe
herein a facile access to 3,4,5-trisubstituted oxazolones by the
Pd(0)-catalyzed coupling of N-alkynyl tert-butyloxycarbamates
with aromatic halides and related electrophiles.
Conditions for the new Pd-catalyzed approach to 3,4,5-
trisubstituted oxazolones were explored by the reaction of N-
alkynyl tert-butyloxycarbamate 1a with iodobenzene (2a). As a
result, treating 1a with 5 mol % of Pd(dba)2, 10 mol % of PPh3
and 1.5 equiv of Cs2CO3 in DMF at 70 °C for 8 h produced the
desired product 4 in 18% yield (Table 1, entry 1). This result
prompted us to investigate the suitable reaction parameters. To
our delight, the readily available K2CO3 or Na2CO3 performed
best, and the yield was improved to 92% (Table 1, entries 4 and
5). Polar solvents, such as DMF, DMSO, MeCN, and NMP,
worked well for this reaction, whereas nonpolar solvents
including dioxane and toluene just led to the recovery of
Received: August 22, 2012
Published: October 8, 2012
© 2012 American Chemical Society
9871
dx.doi.org/10.1021/jo301794w | J. Org. Chem. 2012, 77, 9871−9877

The Journal of Organic Chemistry
Note
a
conversion of chlorobenzene and an isolated yield of 84% of
product 4 (Table 2, entry 29).
Table 1. Optimization of Reaction Parameters
The scope of the reaction with N-alkynyl tert-butyloxycarba-
mates was also briefly investigated. For example, N-alkynyl tert-
butyloxycarbamates 1b and 1c gave rise to 3,4,5-trisubstituted
oxazolones 21 and 22 in respective yields of 84 and 93% (Table
2, entries 34 and 35). Besides the N-Bn substrate 1a, N-alkynyl
tert-butyloxycarbamates, including 1j, 1k, and 1l, coupled with
2a smoothly to give the corresponding products in good yields
(Table 2, entries 42−44). Furthermore, the reaction of aliphatic
N-alkynyl tert-butyloxycarbamates took place well to form the
desired products in reasonable yields (Table 2, entries 45 and
46).
Having established an expeditious route to 3,4,5-trisubsti-
tuted oxazolones, the applicability of this protocol was briefly
studied (Scheme 1). Hakimelahi et al. reported that
phenanthro[9,10-d]oxazol-2-ones could be synthesized by a
photolytic closure of 4,5-diphenyl-oxazol-2-ones.27 Using this
photochemical procedure, we found that the resultant 3,4,5-
trisubstituted oxazolone 7 could be smoothly converted into 3-
benzyl-6-chlorophenanthro[9,10-d]oxazol-2-one (34) in 61%
yield. In addition, a substituted naphtho[1,2-d]oxazol-2-one 35
was synthesized from 19 in good yield (Scheme 1). The
structure of 35 was identified by the X-ray diffraction analysis.
We propose that the Pd-catalyzed coupling of N-alkynyl tert-
butyloxycarbamates with aromatic halides and related electro-
philes proceeds according to the mechanism illustrated in
Scheme 2. The oxidative addition of carbon−halide bond of
R3X to Pd0 catalyst forms the palladium intermediate I,
followed by the oxypalladation of C−C triple bond28−43 via the
intermediate II to provide a palladium species III. A similar
cationic intermediate has also been suggested in previous
studies on the cycloisomerization of N-alkynyl tert-butylox-
ycarbamates.14,15,24 Finally, the cleavage of C−O bond of the
tert-butyloxy group in the intermediate III as well as reductive
elimination results in the formation of 3,4,5-trisubstituted
oxazolones with regeneration of the palladium catalyst (Scheme
2).
b
entry
Pd catalyst
base
ligand
PPh3
solvent
yield (%)
1
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(dba)2
Pd(OAc)2
Pd(PPh3)4
Cs2CO3
Et3N
DMF
DMF
DMF
DMF
DMF
DMSO
CH3CN
NMP
dioxane
toluene
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
18
52
18
92
2
PPh3
3
t-BuOK
Na2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
PPh3
4
PPh3
c
5
PPh3
92 (94)
72
6
PPh3
7
PPh3
90
8
PPh3
75
9
PPh3
trace
NR
43
10
11
12
13
14
15
16
17
18
19
20
PPh3
/
P(o-tol)3
P(p-tol)3
P(2-furyl)3
PCy3·HBF4
Xphos
dppe
44
46
85
36
87
51
dppb
80
PPh3
55
/
85
a
Reaction conditions: 1a (0.25 mmol), 2a (0.30 mmol), Pd catalyst
(0.013 mmol), ligand (0−0.025 mmol), and base (0.38 mmol) in 1
mL of solvent at 70 °C for 8 h. Isolated yield. Yield on a 10 mmol
b
c
scale.
atom was positioned. Notably, the reaction of 4-iodoanisole
(2h) and 4-bromoanisole (3i) afforded oxazolone 11 in only
moderate yields, thus implying that the oxidative addition of
electron-rich carbon−halide bonds might be difficult under the
standard conditions. It was reported that electron-rich
phosphine ligands such as Xphos26 can accelerate the oxidative
addition. On the other hand, Xphos turned out to be one of the
most effective ligands in the initial optimization of the reaction
conditions (Table 1, entry 16). As such, we used Xphos as the
ligand for these two substrates, and as expected, the reaction
provided 11 in good yields within 4 h (Table 2, entries 8 and
18).
We found that the steric hindrance has some effect on this
reaction. For instance, 4-bromoacetophenone (3k) reacted well
with 1a to generate 3,4,5-trisubstituted oxazolone 12 in 74%
yield, while the reaction of 2-bromoacetophenone (3l, Table 2,
entry 21) failed to proceed. 2-Bromomesitylene (3m, Table 2,
entry 22) did not provide the expected product, either. As for
heteroaryl bromides, 2-bromopyridine (3n), 2-bromothiophene
(3o), and 3-bromothiophene (3p), for example, participated
well in this reaction and produced the desired oxazolones in
good yields (Table 2, entries 23−25, respectively). In the case
of alkenyl halides, the reaction of β-bromostyrene (3q) only led
to trace of the desired product, while α-bromostyrene (3r)
furnished 19 in 71% yield under the same conditions (Table 2,
entries 26 and 27, respectively). We also extended this reaction
to benzyl bromide (3s), and the reaction occurred successfully
to provide 20 in 81% yield (Table 2, entry 28). In contrast,
chlorobenzene (3t) proved to be a hindered substrate, only
leading to oxazolone 4 in 37% yield. Fortunately, applying
Xphos26 instead of PPh3 as the ligand resulted in full
In conclusion, we have developed here a new method for the
preparation of highly substituted oxazolones by a Pd-catalyzed
coupling of N-alkynyl tert-butyloxycarbamates with aryl halides
and related electrophiles that involves an oxidative addition
followed by oxypalladation/reductive elimination sequence.
The reaction proceeds smoothly to afford 3,4,5-trisubstituted
oxazolones in satisfactory yields with good functional group
tolerance. Moreover, the resulting products are applicable to
the construction of phenanthrene and naphthalene derivatives,
and we believe that it will be useful for the synthetic
community.
EXPERIMENTAL SECTION
■
General Methods. Column chromatography was performed using
1
silica gel (300−400 mesh). The H NMR, 13C NMR, and 19F NMR
spectra were recorded on a 400 MHz NMR spectrometer. High-
resolution mass spectra (HRMS) analyses were carried out using
electron ionization−quadrupole or electrospray ionization−time-of-
flight (ESI-TOF) mass spectrometry. Pd(PPh3)4, Pd(OAc)2, Pd(dba)2,
and other reagents were obtained commercially and used without
further purification. The N-alkynyl tert-butyloxycarbamate substrates
were prepared from bromoalkynes with secondary tert-butyloxycarba-
mates according to Gagosz’s method.15 To a solution of a
phenylethynyl bromide (90 mg, 0.5 mmol) in 2 mL of toluene was
added tert-butyl benzylcarbamate (124 mg, 0.6 mmol), K3PO4 (254
mg, 1.2 mmol), CuSO4·5H2O (25 mg, 0.1 mmol), and 1.10-
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The Journal of Organic Chemistry
Note
a
Table 2. Scope and Limitations of the Reaction
b
entry
R1/R2
Ph/Bn (1a)
R3X
temp (°C)
time (h)
yield (%)
1
PhI (2a)
70
8
8
8
8
8
8
8
92 (4)
82 (5)
84 (6)
91 (7)
90 (8)
81 (9)
2
Ph/Bn (1a)
2-CH3-C6H4I (2b)
4-F-C6H4I (2c)
4-Cl-C6H4I (2d)
4-Br-C6H4I (2e)
4-CHO-C6H4I (2f)
4-CO2Et-C6H4I (2g)
4-OMe-C6H4I (2h)
4-CH3CO-C6H4I (2i)
PhBr (3a)
70
3
Ph/Bn (1a)
70
4
Ph/Bn (1a)
70
5
Ph/Bn (1a)
70
6
Ph/Bn (1a)
70
7
Ph/Bn (1a)
70
84 (10)
c
c
8
Ph/Bn (1a)
70
8/4
38/65 (11)
81 (12)
84 (4)
9
Ph/Bn (1a)
70
8
8
8
8
8
8
8
8
8
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
Ph/Bn (1a)
110
110
110
110
110
110
110
110
110
110
110
110
110
110
110
110
110
110
80
Ph/Bn (1a)
2-CH3-C6H4Br (3b)
4-F-C6H4Br (3c)
4-Cl-C6H4Br (3d)
2-Cl-C6H4Br (3e)
4-CHO-C6H4Br (3f)
3-CHO-C6H4Br (3g)
4-CO2Et-C6H4Br (3h)
4-OMe-C6H4Br (3i)
3-CN-C6H4Br (3j)
4-CH3CO-C6H4Br (3k)
2-CH3CO-C6H4Br (3l)
2,4,6-(Me)3-C6H2Br (3m)
2-bromopyridine (3n)
2-bromothiophene (3o)
3-bromothiophene (3p)
β-bromostyrene (3q)
α-bromostyrene (3r)
BnBr (3s)
78 (5)
Ph/Bn (1a)
77 (6)
Ph/Bn (1a)
80 (7)
Ph/Bn (1a)
82 (13)
81 (9)
Ph/Bn (1a)
Ph/Bn (1a)
91 (14)
85 (10)
Ph/Bn (1a)
c
c
Ph/Bn (1a)
8/4
47/72 (11)
Ph/Bn (1a)
8
8
8
8
8
8
8
8
8
8
93 (15)
74 (12)
complex
complex
70 (16)
85 (17)
77 (18)
complex
71 (19)
81 (20)
Ph/Bn (1a)
Ph/Bn (1a)
Ph/Bn (1a)
Ph/Bn (1a)
Ph/Bn (1a)
Ph/Bn (1a)
Ph/Bn (1a)
Ph/Bn (1a)
Ph/Bn (1a)
c
c
Ph/Bn (1a)
PhCl (3t)
110
110
110
110
110
70
8/4
37/84 (4)
c
c
Ph/Bn (1a)
2-CH3-C6H4Cl (3u)
4-F-C6H4Cl (3v)
4-CHO-C6H4Cl (3w)
4-CH3CO-C6H4Cl (3x)
PhI (2a)
4
77 (5)
c
c
Ph/Bn (1a)
4
82 (6)
c
c
Ph/Bn (1a)
3
73 (9)
c
c
Ph/Bn (1a)
3
72 (12)
4-CH3-C6H4/Bn (1b)
4-F-C6H4/Bn (1c)
4-Cl-C6H4/Bn (1d)
4-Br-C6H4/Bn (1e)
3-Br-C6H4/Bn (1f)
4-OMe-C6H4/Bn (1g)
3,4-(OMe)2-C6H3/Bn (1h)
2-naphthyl/Bn (1i)
Ph/Ph (1j)
8
8
8
8
8
8
8
8
8
8
8
8
8
84 (21)
93 (22)
83 (23)
71 (24)
68 (25)
95 (26)
90 (27)
85 (28)
92 (29)
85 (30)
61 (31)
72 (32)
71 (33)
PhI (2a)
70
PhI (2a)
70
PhI (2a)
70
PhI (2a)
70
PhI (2a)
70
PhI (2a)
70
PhI (2a)
70
PhI (2a)
70
Ph/4-Cl-C6H4 (1k)
Ph/Cy (1l)
PhI (2a)
70
PhI (2a)
70
TBDPSO(CH2)2/Ph (1m)
n-C8H17/Ph (1n)
PhI (2a)
70
PhI (2a)
70
a
Reaction conditions: 1 (0.25 mmol), R3X (0.30 mmol), Pd(dba)2 (0.013 mmol), PPh3 (0.025 mmol), and K2CO3 (0.38 mmol) in 1 mL of DMF.
Isolated yield. Xphos was used.
b
c
phenanthroline (31 mg, 0.2 mmol). After stirring at 80 °C for 48 h, the
reaction mixture was cooled and filtered through Celite. The filtrate
was concentrated and purified by column chromatography on silica gel
(petroleum ether/EtOAc = 8/1) to afford 92 mg (yield 60%) of N-
alkynyl tert-butyloxycarbamate 1a15 as a colorless oil: 1H NMR
(CDCl3, 400 MHz) δ 1.56 (s, 9H), 4.69 (s, 2H), 7.27−7.50 (m, 10H);
13C NMR (CDCl3, 100 MHz) δ 28.0, 53.5, 70.9, 82.4, 84.3, 123.8,
126.9, 127.7, 128.0, 128.1, 128.4, 130.5, 136.5, 153.7; MS (EI, m/z)
307 (M+, 16), 250 (26), 206 (13), 173 (11).
General Procedure for Pd-Catalyzed Synthesis of 3,4,5-
Trisubstituted Oxazolones. To a mixture of 1a (77 mg, 0.25
mmol), Pd(dba)2 (7.5 mg, 0.013 mmol), K2CO3 (52 mg, 0.38 mmol)
and PPh3 (6.5 mg, 0.025 mmol) in 1 mL of DMF was added 2a (61
mg, 0.3 mmol) under nitrogen atmosphere. After stirring at 70 °C for
8 h, the reaction mixture was quenched with water, extracted with
9873
dx.doi.org/10.1021/jo301794w | J. Org. Chem. 2012, 77, 9871−9877

The Journal of Organic Chemistry
Note
Compound 8. 90% yield (91 mg); white solid: mp 166−168 °C; 1H
NMR (CDCl3, 400 MHz) δ 4.67 (s, 2H), 6.99−7.10 (m, 4H), 7.15−
7.30 (m, 8H), 7.56 (d, J = 8.0 Hz, 2H); 13C NMR (CDCl3, 100 MHz)
δ 45.7, 122.0, 124.3, 124.5, 125.9, 127.3, 127.8, 127.9, 128.5, 128.6,
132.1, 132.5, 134.8, 135.9, 154.7 (CO); IR (KBr) 3089, 1754, 1597,
1343, 1057 cm−1; MS (EI, m/z) 407 (8), 405 (M+, 10), 316 (6), 314
(8), 235 (12); HRMS (EI) calcd for C22H16BrNO2 (M+) 405.0364,
found 405.0363.
Scheme 1. Transformations of 3,4,5-Trisubstituted 2-
Oxazolones
Compound 9. It was prepared from 2f, 3f, and 3w in respective
yields of 81% (72 mg), 81% (72 mg), and 73% (65 mg); white solid:
mp 165−167 °C; 1H NMR (CDCl3, 400 MHz) δ 4.71 (s, 2H), 6.91−
7.02 (m, 2H), 7.09−7.25 (m, 8H), 7.39 (d, J = 8.0 Hz, 2H), 7.91 (d, J
= 8.0 Hz, 2H), 10.08 (s, 1H); 13C NMR (CDCl3, 100 MHz) δ 45.9,
122.0, 124.6, 127.1, 127.3, 127.9, 128.2, 128.5, 128.6, 130.2, 131.2,
133.1, 135.2, 135.7, 136.9, 154.8 (CO), 191.2; IR (KBr) 3047, 2815,
2730, 1757, 1701, 1604, 1374 cm−1; MS (EI, m/z) 355 (M+, 5), 326
(1), 264 (2), 208 (5), 165 (6); HRMS (EI) calcd for C23H17NO3 (M+)
355.1208, found 355.1208.
Scheme 2. Proposed Mechanism
Compound 10. It was prepared from 2g and 3h in respective yields
1
of 84% (84 mg) and 85% (85 mg); white solid: mp 117−119 °C; H
NMR (CDCl3, 400 MHz) δ 1.43 (t, J = 7.2 Hz, 3H), 4.42 (q, J = 7.2
Hz, 2H), 4.69 (s, 2H), 6.95−7.02 (m, 2H), 7.10−7.25 (m, 8H), 7.30
(d, J = 8.0 Hz, 2H), 8.09 (d, J = 8.0 Hz, 2H); 13C NMR (CDCl3, 100
MHz) δ 14.2, 45.8, 61.4, 122.3, 124.5, 127.3, 127.4, 127.9, 128.0,
128.5, 128.6, 130.2, 130.6, 131.5, 131.8, 134.9, 135.8, 154.8 (CO),
165.7; IR (KBr) 3029, 1754, 1714, 1607, 1445 cm−1; MS (EI, m/z)
399 (M+, 2), 326 (1), 308 (1), 235 (12), 105 (100); HRMS (EI) calcd
for C25H21NO4 (M+) 399.1471, found 399.1477. Crystal data for 10
(C25H21NO4, 399.43): monoclinic, space group C2/c, a = 22.874(3)
Å, b =14.556(2) Å, c = 12.4930(12) Å, volume = 4145.3(9) Å3, Z = 8,
specimen 0.341 × 0.237 × 0.187 mm3, T = 296(2) K, SIEMENS P4
diffractometer, absorption coefficient 0.087 mm−1, reflections collected
16761, independent reflections 4747 [R(int) = 0.0542], refinement by
full-matrix least-squares on F2, data/restraints/parameters 4747/0/
272, goodness-of-fit on F2 = 0.983, final R indices [I>2σ(I)] R1 =
0.0537, wR2 = 0.1286, R indices (all data) R1 = 0.1282, wR2 = 0.1629,
largest diff peak and hole 0.159 and −0.180 eÅ−3. Crystallographic
data for compound 10 have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publication no. CCDC
896886.
Compound 11. It was prepared from 2h and 3i in respective yields
of 65% (58 mg) and 72% (64 mg) using Xphos instead of PPh3; white
solid: mp 122−124 °C; 1H NMR (CDCl3, 400 MHz) δ 3.87 (s, 3H),
4.66 (s, 2H), 6.94 (d, J = 8.4 Hz, 2H), 6.98−7.10 (m, 2H), 7.13 (d, J =
8.4 Hz, 2H), 7.25−7.40 (m, 8H); 13C NMR (CDCl3, 100 MHz) δ
45.5, 55.3, 114.7, 118.8, 123.2, 124.1, 127.5, 127.7, 127.9, 128.4, 128.5,
132.0, 134.5, 136.2, 154.9 (CO), 160.7; IR (KBr) 3054, 1754, 1606,
1514 cm−1; MS (EI, m/z) 357 (M+, 6), 326 (1), 266 (20), 238 (8),
133 (8); HRMS (EI) calcd for C23H19NO3 (M+) 357.1365, found
357.1362.
ethyl acetate, washed with brine, dried over Na2SO4 and concentrated.
Column chromatography on silica gel (petroleum ether/EtOAc = 10/
1) gave 92% (75 mg ) of compound 444 as a yellow solid: mp 96−98
°C. Compound 4 was also prepared from 3a in 84% yield (68 mg)
using the general procedure except the reaction temperature was 110
°C: 1H NMR (CDCl3, 400 MHz) δ 4.68 (s, 2H), 6.95−7.10 (m, 2H),
7.16−7.32 (m, 10H), 7.40−7.50 (m, 3H); 13C NMR (CDCl3, 100
MHz) δ 45.6, 123.3, 124.2, 126.9, 127.5, 127.6, 127.6, 127.7, 128.4,
128.5, 129.2, 130.0, 130.5, 134.5, 136.0, 154.8 (CO); IR (KBr)
3034, 1754, 1496, 1445, 1054 cm−1; MS (EI, m/z) 327 (M+, 11), 283
(1), 194 (100), 165 (20).
Compound 5. It was prepared from 2b, 3b, and 3u in respective
yields of 82% (70 mg), 78% (67 mg), and 77% (66 mg); yellow oil: 1H
NMR (CDCl3, 400 MHz) δ 1.84 (s, 3H), 4.52 (d, J = 15.2 Hz, 1H),
4.65 (d, J = 15.2 Hz, 1H), 6.87−6.98 (m, 2H), 7.10−7.25 (m, 9H),
7.27−7.39 (m, 2H), 7.41−7.50 (m, 1H); 13C NMR (CDCl3, 100
MHz) δ 19.0, 45.7, 122.0, 123.5, 126.4, 126.6, 127.4, 127.8, 127.9,
128.0, 128.4, 128.5, 130.4, 130.7, 131.1, 134.3, 135.9, 139.1, 154.9
(CO); IR (KBr) 3063, 3033, 1755, 1602, 1379, 1055 cm−1; MS (EI,
m/z) 341 (M+, 8), 327 (1), 250 (15), 222 (25), 179 (21); HRMS (EI)
calcd for C23H19NO2 (M+) 341.1416, found 341.1411.
Compound 12. It was prepared from 2i, 3k, and 3x in respective
yields of 81% (75 mg), 74% (68 mg), and 72% (66 mg); white solid:
mp 148−150 °C; 1H NMR (CDCl3, 400 MHz) δ 2.66 (s, 3H), 4.69 (s,
2H), 6.92−7.08 (m, 2H), 7.12−7.25 (m, 8H), 7.32 (d, J = 8.4 Hz,
2H), 7.99 (d, J = 8.4 Hz, 2H); 13C NMR (CDCl3, 100 MHz) δ 26.7,
45.8, 122.1, 124.5, 127.2, 127.3, 127.9, 128.1, 128.5, 128.6, 129.0,
130.8, 131.7, 135.0, 135.7, 137.9, 154.8 (CO), 197.2; IR (KBr)
3054, 1755, 1682, 1604, 1380 cm−1; MS (EI, m/z) 369 (M+, 4), 278
(5), 250 (1), 207 (4); HRMS (EI) calcd for C24H19NO3 (M+)
369.1365, found 369.1364.
Compound 6. It was prepared from 2c, 3c, and 3v in respective
yields of 84% (72 mg), 77% (66 mg), and 82% (71 mg); white solid:
mp 104−106 °C; 1H NMR (CDCl3, 400 MHz) δ 4.67 (s, 2H), 6.95−
7.05 (m, 2H), 7.12 (t, J = 8.4 Hz, 2H), 7.20−7.42 (m, 10H); 19F NMR
(CDCl3, 282 MHz) δ −110.0; 13C NMR (CDCl3, 100 MHz) δ 45.6,
116.5 (d, J = 22.6 Hz), 122.1, 123.0 (d, J = 3.0 Hz), 124.2, 127.4,
127.5, 127.8 (d, J = 4.6 Hz), 128.5, 128.6, 132.6, 132.7, 134.8, 135.9,
154.7 (CO), 163.5 (d, J = 250.0 Hz); IR (KBr) 3054, 1754, 1606,
1514 cm−1; MS (EI, m/z) 345 (M+, 6), 254 (7), 226 (7), 183 (6);
HRMS (EI) calcd for C22H16FNO2 (M+) 345.1165, found 345.1169.
Compound 7. It was prepared from 2d and 3d in respective yields
1
Compound 13. 82% yield (74 mg); yellow oil: H NMR (CDCl3,
1
400 MHz) δ 4.45 (d, J = 15.2 Hz, 1H), 4.88 (d, J = 15.2 Hz, 1H),
6.88−6.98 (m, 2H), 7.05−7.12 (m, 1H), 7.18−7.30 (m, 9H), 7.39−
7.50 (m, 1H), 7.54−7.61 (m, 1H); 13C NMR (CDCl3, 100 MHz) δ
46.0, 120.1, 123.9, 126.3, 127.4, 127.4, 127.7, 127.8, 128.4, 128.5,
130.1, 131.7, 133.1, 135.3, 135.6, 135.7, 154.7 (CO); IR (KBr)
3063, 1758, 1600, 1383, 1237 cm−1; MS (EI, m/z) 363 (3), 361 (M+,
9), 272 (1), 270 (4), 235 (15); HRMS (EI) calcd for C22H16ClNO2
(M+) 361.0870, found 361.0863.
of 91% (82 mg) and 80% (72 mg); white solid: mp 159−161 °C; H
NMR (CDCl3, 400 MHz) δ 4.68 (s, 2H), 6.90−7.01 (m, 2H), 7.14 (d,
J = 7.2 Hz, 2H), 7.21−7.32 (m, 8H), 7.40 (d, J = 7.6 Hz, 2H); 13C
NMR (CDCl3, 100 MHz) δ 45.7, 122.0, 124.3, 125.4, 127.3, 127.5,
127.8, 127.9, 128.5, 128.6, 129.6, 131.9, 134.8, 135.8, 136.2, 154.7
(CO); IR (KBr) 3093, 3032, 1754, 1598, 1444 cm−1; MS (EI, m/z)
363 (1), 361 (M+, 3), 270 (5), 272 (1), 235 (3); HRMS (EI) calcd for
C22H16ClNO2 (M+) 361.0870, found 361.0867.
9874
dx.doi.org/10.1021/jo301794w | J. Org. Chem. 2012, 77, 9871−9877

The Journal of Organic Chemistry
Note
1
Compound 14. 91% yield (81 mg); yellow oil: H NMR (CDCl3,
400 MHz) δ 4.68 (s, 2H), 6.86−7.01 (m, 2H), 7.12−7.30 (m, 8H),
7.38−7.50 (m, 1H), 7.52−7.70 (m, 2H), 7.99 (d, J = 7.6 Hz, 1H), 9.90
(s, 1H); 13C NMR (CDCl3, 100 MHz) δ 45.9, 121.7, 124.4, 127.2,
127.3, 127.9, 128.0, 128.2, 128.5, 128.6, 130.0, 130.5, 132.1, 135.1,
135.8, 136.3, 137.0, 154.7 (CO), 190.9; IR (KBr) 3062, 2834, 2728,
1751, 1600, 1447 cm−1; MS (EI, m/z) 355 (M+, 6), 326 (2), 264 (3),
242 (7); HRMS (EI) calcd for C23H17NO3 (M+) 355.1208, found
355.1215.
(CDCl3, 100 MHz) δ 45.7, 115.5 (d, J = 21.2 Hz), 122.9, 124.0 (d, J =
2.9 Hz), 126.2 (d, J = 7.6 Hz), 126.8, 127.5, 127.8, 128.5, 129.3, 130.1,
130.6, 133.8, 136.0, 154.7 (CO), 163.2 (d, J = 247.0 Hz); IR (KBr)
3050, 1754, 1606, 1514 cm−1; MS (EI, m/z) 345 (M+, 2), 297 (1), 254
(2), 226 (4), 183 (4); HRMS (EI) calcd for C22H16FNO2 (M+)
345.1165, found 345.1166.
Compound 23. 83% yield (75 mg); yellow solid: mp 156−158 °C;
1H NMR (CDCl3, 400 MHz) δ 4.67 (s, 2H), 6.90−7.02 (m, 2H), 7.17
(s, 4H), 7.19−7.25 (m, 5H), 7.44 (t, J = 7.6 Hz, 2H), 7.60−7.70 (m,
1H); 13C NMR (CDCl3, 100 MHz) δ 45.7, 123.8, 125.4, 126.2, 126.7,
127.5, 127.8, 128.5, 128.7, 129.4, 130.2, 130.5, 133.3, 133.6, 135.9,
154.6 (CO); IR (KBr) 3087, 3062, 1757, 1666, 1499, 1350 cm−1;
MS (EI, m/z) 363 (3), 361 (M+, 10), 272 (3), 270 (9), 165 (2);
HRMS (EI) calcd for C22H16ClNO2 (M+) 361.0870, found 361.0864.
Compound 24. 71% yield (72 mg); yellow solid: mp 130−132 °C;
1H NMR (CDCl3, 400 MHz) δ 4.67 (s, 2H), 6.81−6.97 (m, 2H),
6.99−7.10 (m, 2H), 7.12−7.25 (m, 5H), 7.27−7.38 (m, 2H), 7.41−
7.50 (m, 2H), 7.51−7.61 (m, 1H); 13C NMR (CDCl3, 100 MHz) δ
45.7, 121.5, 123.9, 125.7, 126.6, 126.7, 127.5, 127.8, 128.5, 129.4,
130.2, 130.4, 131.6, 133.6, 135.9, 154.6 (CO); IR (KBr) 3086, 3062,
1758, 1496, 1350, 1070 cm−1; MS (EI, m/z) 407 (11), 405 (M+, 14),
316 (9), 314 (11), 235 (12); HRMS (EI) calcd for C22H16BrNO2
(M+) 405.0364, found 405.0361.
1
Compound 15. 93% yield (82 mg); yellow oil: H NMR (CDCl3,
400 MHz) δ 4.68 (s, 2H), 6.90−7.02 (m, 2H), 7.15−7.30 (m, 8H),
7.39 (s, 1H), 7.41−7.50 (m, 1H), 7.55−7.61 (m, 1H), 7.75 (d, J = 7.6
Hz, 1H); 13C NMR (CDCl3, 100 MHz) δ 45.9, 113.5, 117.4, 120.7,
124.4, 126.8, 127.2, 128.0, 128.3, 128.6, 128.7, 130.1, 133.3, 134.1,
134.9, 135.3, 135.5, 154.5 (CO); IR (KBr) 3064, 2231, 1755, 1602,
1351 cm−1; MS (EI, m/z) 352 (M+, 12), 326 (1), 261 (5), 190 (7);
HRMS (EI) calcd for C23H16N2O2 (M+) 352.1212, found 352.1213.
1
Compound 16. 70% yield (57 mg); yellow oil: H NMR (CDCl3,
400 MHz) δ 5.03 (s, 2H), 6.90−7.03 (m, 2H), 7.12−7.41 (m, 10H),
7.50−7.64 (m, 1H), 8.78−8.85 (m, 1H); 13C NMR (CDCl3, 100
MHz) δ 45.7, 122.1, 123.8, 125.4, 125.9, 127.3, 127.6, 128.4, 128.5,
128.5, 136.2, 136.3, 136.8, 147.4, 150.2, 154.8 (CO); IR (KBr)
3062, 1755, 1585, 1349, 1054 cm−1; MS (EI, m/z) 328 (M+, 20), 237
(59), 223 (3), 209 (15), 167 (40); HRMS (EI) calcd for C21H16N2O2
(M+) 328.1212, found 328.1210.
1
Compound 25. 68% yield (69 mg); yellow oil: H NMR (CDCl3,
400 MHz) δ 4.67 (s, 2H), 6.91−7.05 (m, 3H), 7.09−7.15 (m, 1H),
7.19−7.35 (m, 6H), 7.40−7.50 (m, 3H), 7.51−7.59 (m, 1H); 13C
NMR (CDCl3, 100 MHz) δ 45.7, 122.6, 124.5, 126.5, 127.1, 127.5,
127.8, 128.5, 129.4, 129.6, 129.9, 130.3, 130.4, 133.0, 135.8, 154.5
(CO); IR (KBr) 3086, 3055, 1758, 1496, 1347 cm−1; MS (EI, m/z)
407 (17), 405 (M+, 21), 316 (19), 314 (24), 235 (35); HRMS (EI)
calcd for C22H16BrNO2 (M+) 405.0364, found 405.0368.
Compound 17. 85% yield (71 mg); white solid: mp 122−124 °C;
1H NMR (CDCl3, 400 MHz) δ 4.73 (s, 2H), 6.99 (d, J = 3.6 Hz, 1H),
7.02−7.15 (m, 3H), 7.17−7.30 (m, 6H), 7.35−7.42 (m, 2H), 7.55 (d, J
= 5.2 Hz, 1H); 13C NMR (CDCl3, 100 MHz) δ 45.6, 115.9, 124.6,
126.3, 127.3, 127.4, 127.8, 127.9, 128.1, 128.4, 128.5, 129.8, 131.5,
136.0, 136.9, 154.4 (CO); IR (KBr) 3070, 1745, 1597, 1382, 1245,
1053 cm−1; MS (EI, m/z) 333 (M+, 10), 275 (1), 242 (29), 214 (2),
176 (2); HRMS (EI) calcd for C20H15NO2S (M+) 333.0823, found
333.0822.
Compound 26. 95% yield (85 mg); yellow solid: mp 156−158 °C;
1H NMR (CDCl3, 400 MHz) δ 3.74 (s, 3H), 4.67 (s, 2H), 6.69−6.80
(m, 2H), 6.97−7.09 (m, 2H), 7.15−7.25 (m, 7H), 7.41 (t, J = 7.6 Hz,
2H), 7.48−7.51 (m, 1H); 13C NMR (CDCl3, 100 MHz) δ 45.5, 55.1,
113.8, 120.3, 121.5, 125.8, 127.1, 127.4, 127.6, 128.4, 129.1, 129.8,
130.6, 134.6, 136.1, 154.9 (CO), 159.0; IR (KBr) 3054, 1754, 1606,
1514 cm−1; MS (EI, m/z) 357 (M+, 3), 327 (10), 266 (2), 135 (100);
HRMS (EI) calcd for C23H19NO3 (M+) 357.1365, found 357.1360.
1
Compound 18. 77% yield (64 mg); yellow oil: H NMR (CDCl3,
400 MHz) δ 4.70 (s, 2H), 6.85−6.95 (m, 1H), 7.02−7.11 (m, 2H),
7.20−7.37 (m, 9H), 7.39−7.51 (m, 1H); 13C NMR (CDCl3, 100
MHz) δ 45.7, 118.4, 124.3 126.7, 127.3, 127.3, 127.7, 127.8, 128.0,
128.5, 128.5, 128.6, 135.3, 136.2, 154.8 (CO); IR (KBr) 3065, 1744,
1600, 1382, 1242, 1053 cm−1; MS (EI, m/z) 333 (M+, 6), 242 (12),
214 (2), 171 (3); HRMS (EI) calcd for C20H15NO2S (M+) 333.0823,
found 333.0820.
1
Compound 27. 90% yield (87 mg); yellow oil: H NMR (CDCl3,
400 MHz) δ 3.57 (s, 3H), 3.80 (s, 3H), 4.66 (s, 2H), 6.69 (d, J = 8.4
Hz, 1H), 6.73−6.80 (m, 1H), 6.86−6.90 (m, 1H), 6.98−7.10 (m, 2H),
7.14−7.25 (m, 5H), 7.37−7.50 (m, 3H); 13C NMR (CDCl3, 100
MHz) δ 45.6, 55.3, 55.7, 107.4, 110.9, 117.0, 120.5, 121.7, 127.2,
127.4, 127.6, 128.4, 129.1, 129.8, 130.7, 134.5, 136.0, 148.5, 148.6,
154.8 (CO); IR (KBr) 3072, 3015, 1757, 1589, 1612, 1447 cm−1;
HRMS (ESI) calcd for C24H21NO4 (M+) 387.1471, found 387.1465.
Compound 28. 85% yield (80 mg); white solid: mp 129−131 °C;
1H NMR (CDCl3, 400 MHz) δ 4.72 (s, 2H), 6.96−7.07 (m, 2H),
7.12−7.20 (m, 1H), 7.22−7.34 (m, 5H), 7.38−7.62 (m, 6H), 7.66−
7.75 (m, 2H), 7.91 (s, 1H); 13C NMR (CDCl3, 100 MHz) δ 45.7,
121.9, 123.4, 123.7, 125.0, 126.2, 126.4, 127.0, 127.5, 127.7, 128.0,
128.1, 128.5, 129.2, 130.1, 130.7, 132.4, 133.0, 134.6, 136.0, 154.8
(CO); IR (KBr) 3061, 1751, 1624, 1384, 1048 cm−1; MS (EI, m/z)
377 (M+, 2), 286 (1), 215 (4), 155 (100), 127 (43); HRMS (EI) calcd
for C26H19NO2 (M+) 377.1416, found 377.1412.
1
Compound 19. 71% yield (63 mg); yellow oil: H NMR (CDCl3,
400 MHz) δ 4.53 (s, 2H), 5.47 (s, 1H), 6.02 (s, 1H), 7.07−7.20 (m,
2H), 7.21−7.42 (m, 11H), 7.55−7.65 (m, 2H); 13C NMR (CDCl3,
100 MHz) δ 45.8, 122.4, 122.5, 124.4, 126.1, 127.5, 127.6, 127.7,
127.8, 128.4, 128.5, 129.0, 129.1, 135.4, 135.5, 136.0, 136.3, 154.9
(CO); IR (KBr) 3060, 3031, 1747, 1600, 1348 cm−1; MS (EI, m/z)
353 (M+, 38), 262 (30), 219 (24), 191 (59), 156 (14); HRMS (EI)
calcd for C24H19NO2 (M+) 353.1416, found 353.1421.
Compound 20. 81% yield (69 mg); white solid: mp 147−149 °C;
1H NMR (CDCl3, 400 MHz) δ 3.91 (s, 2H), 4.61 (s, 2H), 7.18 (d, J =
6.8 Hz, 4H), 7.27−7.42 (m, 9H), 7.48−7.60 (m, 2H); 13C NMR
(CDCl3, 100 MHz) δ 29.3, 45.4, 120.7, 125.0, 126.9, 127.3, 127.6,
127.8, 127.9, 128.1, 128.8, 129.2, 135.4, 136.0, 136.2, 155.4 (CO);
IR (KBr) 3061, 2925, 1758, 1494, 1396 cm−1; MS (EI, m/z) 341 (M+,
4), 250 (1), 207 (2), 178 (2), 144 (3); HRMS (EI) calcd for
C23H19NO2 (M+) 341.1416, found 341.1414.
Compound 29. 92% yield (72 mg); white solid: mp 191−193 °C;45
1H NMR (CDCl3, 400 MHz) δ 7.09−7.20 (m, 2H), 7.24−7.41 (m,
13H); 13C NMR (CDCl3, 100 MHz) δ 123.5, 125.0, 126.8, 127.0,
127.5, 127.8, 128.0, 128.4, 128.9, 129.5, 130.2, 133.5, 135.0, 153.5
(CO); IR (KBr) 1750, 1594, 1374, 1267 cm−1; MS (EI, m/z) 313
(M+, 13), 254 (1), 236 (2), 180 (100), 165 (28).
Compound 30. 85% yield (74 mg); white solid: mp 218−220 °C;
1H NMR (CDCl3, 400 MHz) δ 7.08 (d, J = 8.4 Hz, 2H), 7.20−7.32
(m, 7H), 7.34−7.43 (m, 5H); 13C NMR (CDCl3, 100 MHz) δ 123.1,
125.0, 126.7, 127.3, 128.0, 128.2, 128.5, 129.2, 129.7, 130.2, 132.1,
133.6, 135.3, 153.3 (CO); IR (KBr) 3476, 1746, 1594, 1493, 1374
cm−1; MS (EI, m/z) 349 (5), 347 (M+, 15), 270 (1), 216 (32), 214
Compound 21. 84% yield (72 mg); white solid: mp 112−114 °C;
1H NMR (CDCl3, 400 MHz) δ 2.28 (s, 3H), 4.67 (s, 2H), 7.01 (d, J =
8.4 Hz, 4H), 7.15−7.30 (m, 7H), 7.39−7.51 (m, 3H); 13C NMR
(CDCl3, 100 MHz) δ 21.1, 45.6, 122.5, 124.3, 124.9, 127.1, 127.5,
127.7, 128.5, 129.0, 129.1, 129.8, 130.6, 134.7, 136.1, 137.6, 154.9
(CO); IR (KBr) 3061, 1751, 1517, 1346, 1056 cm−1; MS (EI, m/z)
341 (M+, 6), 250 (19), 234 (7), 173 (13); HRMS (EI) calcd for
C23H19NO2 (M+) 341.1416, found 341.1416.
Compound 22. 93% yield (80 mg); white solid: mp 80−82 °C; 1H
NMR (CDCl3, 400 MHz) δ 4.67 (s, 2H), 6.89 (t, J = 8.8 Hz, 2H),
6.95−7.10 (m, 2H), 7.17−7.25 (m, 7H), 7.38−7.47 (m, 2H), 7.49−
7.60 (m, 1H); 19F NMR (CDCl3, 282 MHz) δ −112.8; 13C NMR
9875
dx.doi.org/10.1021/jo301794w | J. Org. Chem. 2012, 77, 9871−9877

The Journal of Organic Chemistry
Note
(100); HRMS (EI) calcd for C21H14ClNO2 (M+) 347.0713, found
347.0710.
AUTHOR INFORMATION
Corresponding Author
*E-mail: gangguo@zjnu.cn.
Notes
■
Compound 31. 61% yield (49 mg); yellow solid: mp 151−153 °C;
1H NMR (CDCl3, 400 MHz) δ 1.05−1.19 (m, 3H), 1.50−1.60 (m,
1H), 1.69−1.81 (m, 4H), 2.10−2.22 (m, 2H), 3.25−3.38 (m, 1H),
7.11−7.22 (m, 5H), 7.28−7.47 (m, 2H), 7.51−7.61 (m, 3H); 13C
NMR (CDCl3, 100 MHz) δ 24.7, 25.6, 29.7, 54.4, 123.6, 124.1, 127.3,
127.7, 128.0, 128.3, 129.5, 130.1, 130.7, 134.0, 153.6 (CO); IR
(KBr) 3050, 2926, 2855, 1760, 1588, 1158 cm−1; MS (EI, m/z) 319
(M+, 4), 237 (83), 180 (12); HRMS (EI) calcd for C21H21NO2 (M+)
319.1572, found 319.1570.
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We are deeply appreciative of the financial support from the
National Natural Science Foundation of China (No. 20902084
and 21172199), the Natural Science Foundation of Zhejiang
Province (LR12B02001), Qianjiang Talents Project of the
Science and Technology Office in Zhejiang Province
(2010R10016), and the Program for Changjiang Scholars and
Innovative Research Team in Chinese Universities (IRT0980).
1
Compound 32. 72% yield (93 mg); yellow oil: H NMR (CDCl3,
400 MHz) δ 1.09 (s, 9H), 2.83 (t, J = 6.0 Hz, 2H), 4.01 (t, J = 6.0 Hz,
2H), 7.05−7.20 (m, 4H), 7.22−7.35 (m, 6H) 7.36−7.50 (m, 6H),
7.60−7.72 (m, 4H); 13C NMR (CDCl3, 100 MHz) δ 19.3, 26.9, 28.6,
61.2, 125.0, 126.4, 126.6, 127.4, 127.8, 128.5, 128.6, 129.0, 129.1,
129.8, 133.4, 134.3, 135.3, 135.5, 154.3 (CO); IR (KBr) 3070, 2930,
2857, 1762, 1598, 1381 cm−1; HRMS (ESI) calcd for C33H33NO3Si
(M+) 519.2230, found 519.2227.
REFERENCES
■
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1
Compound 33. 71% yield (62 mg); yellow oil: H NMR (CDCl3,
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(13) Yamashita, M.; Lee, S.-H.; Koch, G.; Zimmermann, J.; Clapham,
400 MHz) δ 0.88 (t, J = 7.2 Hz, 3H), 1.20−1.40 (m, 10H), 1.61−1.72
(m, 2H), 2.44 (t, J = 7.6 Hz, 2H), 6.97−7.08 (m, 2H), 7.12−7.20 (m,
2H) 7.22−7.25 (m, 1H), 7.28−7.40 (m, 5H); 13C NMR (CDCl3, 100
MHz) δ 14.0, 22.6, 24.8, 27.5, 28.9, 29.0, 29.1, 31.7, 123.0, 126.2,
126.9, 127.2, 128.4, 128.5, 128.8, 129.0, 134.2, 138.3, 154.3 (CO);
IR (KBr) 3061, 2926, 2855, 1766, 1598, 1158 cm−1; MS (EI, m/z) 349
(M+, 20), 276 (1), 250 (100), 204 (5), 180 (21); HRMS (EI) calcd for
C23H27NO2 (M+) 349.2042, found 349.2040.
Compound 34. It was prepared from 7 according to the method
described in the literature27 in 61% yield (55 mg); white solid: mp
255−257 °C; 1H NMR (CDCl3, 400 MHz) δ 5.55 (s, 2H), 7.28−7.54
(m, 6H), 7.61−7.74 (m, 1H), 7.75−7.83 (m, 1H), 7.86 (d, J = 8.8 Hz,
1H), 8.18 (d, J = 8.0 Hz, 1H), 8.59 (d, J = 8.4 Hz, 1H), 8.68 (s, 1H);
13C NMR (CDCl3, 100 MHz) δ 47.9, 119.0, 120.3, 120.5, 121.5, 122.4,
123.3, 123.9, 126.2, 126.3, 126.6, 127.7, 128.1, 128.4, 129.2, 129.8,
131.9, 135.5, 135.6, 156.0 (CO); IR (KBr) 3085, 1754, 1522, 1355,
1052 cm−1; MS (EI, m/z) 361 (1), 359 (M+, 3), 268 (25), 177 (100);
HRMS (EI) calcd for C22H14ClNO2 (M+), 359.0713, found 359.0720.
Compound 35. 60% yield (53 mg); white solid: mp 148−150 °C;
1H NMR (CDCl3, 400 MHz) δ 4.89 (s, 2H), 6.60 (d, J = 7.2 Hz, 2H),
7.01−7.15 (m, 3H), 7.19 (d, J = 7.2 Hz, 2H), 7.35 (t, J = 7.6 Hz, 2H),
7.41−7.57 (m, 3H), 7.60−7.71 (m, 1H), 7.82 (d, J = 8.4 Hz, 1H), 8.13
(d, J = 8.4 Hz, 1H); 13C NMR (CDCl3, 100 MHz) δ 46.9, 118.6,
119.4, 124.2, 125.3, 125.7, 126.3, 126.3, 127.2, 127.3, 128.0, 128.1,
128.2, 128.3, 129.3, 129.7, 135.3, 136.8, 137.3, 156.1 (CO); IR
(KBr) 3077, 1753, 1518, 1355, 1052 cm−1; MS (EI, m/z) 352 (5), 351
(M+, 18), 260 (56), 232 (64), 203 (100); HRMS (EI) calcd for
C24H17NO2 (M+) 351.1259, found 351.1267. Crystal data for 35
(C24H17NO2, 351.39): monoclinic, space group P2(1)/c, a =
6.9736(2) Å, b =17.1873(6) Å, c = 15.2945(5) Å, volume
=1819.13(10) Å3, Z = 4, specimen 0.52 × 0.32 × 0.12 mm3, T =
296(2) K, SIEMENS P4 diffractometer, absorption coefficient 0.082
mm−1, reflections collected 28522, independent reflections 4165
[R(int) = 0.0328], refinement by full-matrix least-squares on F2, data/
restraints/parameters 4165/0/245, goodness-of-fit on F2 = 1.026, final
R indices [I>2σ(I)] R1 = 0.0396, wR2 = 0.0987, R indices (all data) R1
= 0.0639, wR2 = 0.1127, largest diff peak and hole 0.149 and −0.133
eÅ−3. Crystallographic data for compound 35 have been deposited
with the Cambridge Crystallographic Data Centre as supplementary
publication no. CCDC 896692.
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ASSOCIATED CONTENT
■
S
* Supporting Information
Spectroscopic data of products 4−35 and crystal data (CIF) for
10 and 35. This material is available free of charge via the
Internet at http://pubs.acs.org.
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