Metal triflate-catalyzed Se-Se bond cleavage and the selective additions under mild conditions

Article abstract of DOI:10.1080/00397911.2010.494813

Metal triflate-catalyzed Se-Se bond cleavage would generate selenyl cations, which could add to activated C=C double bond selectively. The reaction conditions were mild and could be easily handled. The cleavage of Se-Se bond in this novel way under mild c

Full text of DOI:10.1080/00397911.2010.494813

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Metal Triflate–Catalyzed Se-Se Bond
Cleavage and the Selective Additions
Under Mild Conditions
Lei Yu a , Lingfeng Ren a , Rong Guo a & Tian Chen a
a School of Chemistry and Chemical Engineering , Yangzhou
University , Yangzhou, China
Published online: 02 May 2011.
To cite this article: Lei Yu , Lingfeng Ren , Rong Guo & Tian Chen (2011) Metal Triflate–Catalyzed Se-
Se Bond Cleavage and the Selective Additions Under Mild Conditions, Synthetic Communications: An
International Journal for Rapid Communication of Synthetic Organic Chemistry, 41:13, 1958-1968,
DOI: 10.1080/00397911.2010.494813
To link to this article: http://dx.doi.org/10.1080/00397911.2010.494813
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Synthetic Communications1, 41: 1958–1968, 2011
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397911.2010.494813
METAL TRIFLATE–CATALYZED Se-Se BOND
CLEAVAGE AND THE SELECTIVE ADDITIONS
UNDER MILD CONDITIONS
Lei Yu, Lingfeng Ren, Rong Guo, and Tian Chen
School of Chemistry and Chemical Engineering, Yangzhou University,
Yangzhou, China
GRAPHICAL ABSTRACT
Abstract Metal triflate–catalyzed Se-Se bond cleavage would generate selenyl cations,
=
which could add to activated C C double bond selectively. The reaction conditions
were mild and could be easily handled. The cleavage of Se-Se bond in this novel way under
mild conditions might expand the view of organic synthesis and facilitate new synthetic
strategies.
Keywords Allenes; electrophilic addition; regioselectivity; selenium; stereoselectivity
Selenium-containing organic compounds have attracted chemists’ attention for a
long period because of their wide applications in organic synthesis and their activity
in bioorganic chemistry.[1] Ordinarily, the free radical additions or transition metal–
catalyzed additions of diphenyldiselenide to unsaturated organic compounds are
convenient methods of introducing selenium atoms.[2] Besides these methods,
recently we have found that Lewis acids could also catalyze Se-Se bond cleavage.
Because of the totally different mechanisms, the Lewis acid–catalyzed additions of
diphenyldiselenide might bring quite different results. The Lewis acid–catalyzed
addition of diphenyldiselenide to methylenecyclopropanes (MCPs) leads to cyclobu-
tane-1,1-diylbis(phenylselane) derivatives,[3] which are different from the products of
2h,2k
]
free radical addition (Scheme 1).[
Encouraged by previous works, we are inter-
ested in investigating the Lewis acid–catalyzed additions of diphenyldiselenide to
other activated olefins.
Received February 1, 2010.
Address correspondence to Lei Yu, School of Chemistry and Chemical Engineering, Yangzhou
University, Yangzhou 225002, China. E-mail: yulei@yzu.edu.cn
1958

METAL TRIFLATE–CATALYZED BOND CLEAVAGE
1959
Scheme 1. Reaction of MCPs with PhSeSePh under different conditions.
Allenes are a kind of organic compounds that have attracted attentions from
chemists for years.[4] Containing cumulated carbon–carbon double bonds, allenes
are highly activated and could undergo a variety of reactions with high selectivity
under mild conditions. These include electrophilic additions,[5] free radical addi-
tions,[6] transition metal–catalyzed reactions,[7] and so on. Herein, we report the
Lewis acid–catalyzed addition of diphenyldiselenide to allenes.
We initially investigated the reaction of 1-phenylallene (1a) with diphenyldise-
lenide catalyzed by TiCl4 at ꢀ75 ꢁC to rt. However, no desired adduct was observed
(Table 1, entry 1). Metal triflates are a kind of Lewis acids that could catalyze a
variety of reactions under mild conditions.[8] Therefore, we tried to employ Cu(OTf)2
as Lewis acid catalyst. After stirring in dichloromethane (DCM) for 9 h, the regio-
selective 2,3-adduct 2a could be separated in 21% yield with poor stereoselectivity
Table 1. Addition of PhSeSePh to 1-phenylallene (1a) catalyzed by different Lewis acidsa
Entry
LAb
TiCl4
Temperature
Time (h)c
Yield of 2a (Z=E)d
1
2
3
4
5
6
7
8
9
ꢀ75 ꢁC to rt
Overnight
9
0
Cu(OTf)2
Zn(OTf)2
Co(OTf)2
Be(OTf)2
Mg(OTf)2
Y(OTf)3
rt
rt
rt
rt
rt
rt
rt
rt
21 (63=37)
36 (82=18)
37 (81=19)
Trace
24
24
10
10
24
30
20
44 (74=26)
56 (79=21)
58 (90=10)
58 (78=22)
Yb(OTf)3
Sm(OTf)3
a0.24 mmol of 1a (20% excess), 0.2 mmol of PhSeSePh, and 1 mL of DCM were employed. The dosage
of LA was 0.5 equiv in entry 1 and 0.2 equiv in entries 2 to 9.
bLA ¼ Lewis acid.
cThe reaction was monitored by TLC (eluent: petroleum ether).
dIsolated yields based on PhSeSePh. Z=E ratio was calculated from 1H NMR spectrum.

1960
L. YU ET AL.
Scheme 2. Configuration of Z-2a.
(Z=E ¼ 63=37, Table 1, entry 2). The configuration of 2a was established by the
nuclear overhauser effect spectroscopy (NOESY) spectrum studies (Scheme 2).
Further screening demonstrated that the stereoselectivity could be obviously enhanced
when Zn(OTf)2, Co(OTf)2, or Mg(OTf)2 was employed (Table 1, entries 3, 4, and 6).
Catalyzed by rare-earth metal triflates, the reaction could be further optimized
(Table 1, entries 7–9), especially when Yb(OTf)3 was employed (Table 1, entry 8).
We then tried to examine the Yb(OTf)3-catalyzed reactions under different
conditions. The experimental results showed that dichloroethane (DCE) was a better
solvent, and the reaction could be further optimized at a higher temperature (Table 2,
entries 5–7). The dosage of Yb(OTf)3 could be cut to 5% without the decrease of
product yield (Table 2, entries 7–9). The Lewis acid catalyst was essential, and the
reaction did not happen in the absence of Yb(OTf)3 (Table 2, entry 10).
Allyl derivatives are important building blocks in organic synthesis.[9] Contain-
ing selenium element and an allyl structure unit, 2,3-diphenylselenyl-1-propene
a
Table 2. Optimization of the reactions catalyzed by Yb(OTf)3
Entry
Solvent
DCM
THF
LA (%)
Temperature (ꢁC)
Time (h)b
Yield of 2a (Z=E)c
1
2
20
20
20
20
20
20
20
10
5
rt
rt
30
24
48
50
36
28
10
10
10
24
58 (90=10)
0
3
Cyclohexane
CCl4
DCE
rt
21 (80=20)
30 (75=25)
52 (86=14)
56 (85=15)
63 (80=20)
61 (80=20)
67 (83=17)
NR
4
rt
5
rt
6
DCE
DCE
40
60
60
60
60
7
8
DCE
DCE
DCE
9
10
0
a0.24 mmol of 1a (20% excess), 0.2 mmol of PhSeSePh, and 1 mL of solvent were employed.
bThe reaction was monitored by TLC (eluent: petroleum ether).
cIsolated yields based on PhSeSePh. Z=E ratio was calculated from 1H NMR spectrum.

METAL TRIFLATE–CATALYZED BOND CLEAVAGE
1961
Table 3. Synthesis of 2,3-diphenylselenyl-1-propenes
Entry
R1, R2
Yield of 2 (Z=E)a
1
2
3
4
5
6
7
8
H, C6H5 (1a)
H, 1-C10H7 (1b)
H, Bn (1c)
67 (83=17) (2a)
50 (70=30) (2b)
57 (81=19) (2c)
55 (75=25) (2d)
52 (74=26) (2e)
72 (ꢀ) (2f)
H, c-C6H11 (1d)
H, n-C5H11 (1e)
C6H5, C6H5 (1f)
C2H5, C6H5 (1g)
c-C6H11, C6H5 (1h)
64 (87=13) (2g)
70 (98=2) (2h)
aIsolated yields. The configuration of 2 was established by the NOESY spectrum studies as well as Ref.
2i, and the Z=E ratio was calculated from the 1H NMR spectrum.
might be of potential applicable value.[10] Therefore, we then tried to examine the
application scope of this reaction. A series of allenes were employed to give the cor-
responding 2,3-diphenylselenyl-1-propenes, and the results are listed in Table 3. It is
notable that the reaction had excellent regioselectivity and only 2,3-adducts were
generated. Meanwhile, in most cases, the stereoselectivity of this reaction was high,
especially when disubstituted allenes were employed (Table 3, entries 7 and 8).
Disulfides have properties similar to diselenides. However, when diaryl disulfide
was employed, no reaction was observed.
Scheme 3. Possible mechanism for the Yb(OTf)3-catalyzed addition of PhSeSePh to allenes.

1962
L. YU ET AL.
Table 4. Additions of PhSeSePh to MCPs catalyzed by Yb(OTf)3
Entry
R1, R2
Yield of 6 (Z=E)a
1
2
3
4
5
H, C7H15 (5a)
H, C9H19 (5b)
56 (36=64) (6a)
81 (39=61) (6b)
30 (ꢀ) (6c)
24 (ꢀ) (6d)
0b
-(CH2)5- (5c)
-CH2CH2CH(Ph)CH2CH2- (5d)
p-BrC6H5 (5e)
aIsolated yields. The configuration of 6 was established by the NOESY spectrum studies as well as Ref.
2 h, and the Z=E ratio was calculated from the 1H NMR spectrum.
bCompound 7 was obtained (Fig. 1).
On the basis of references as well as the experimental results mentioned pre-
viously, here we propose the possible mechanisms. Yb(OTf)3-mediated reaction of
diphenyldiselenide with allenes 1 gave the intermediate allylic carbon cation 3 and
Yb(OTf)3SePh anion,[3,11] which could be transformed to the p-allylic metal complex
4. When R1 > R2, the intermediate 4A should be the more stable than 4B. Further
reductive elimination led to 2 with Z-configuration as the major product (Scheme 3).
Yb(OTf)3 is an environmentally friendly Lewis acid catalyst that is tolerance to
moisture. Compared with the traditional Lewis acid catalysts (e.g., AlCl3, TiCl4,
ZnCl2), the dosage of Yb(OTf)3 could be lower. Therefore, we also tried to optimize
the Lewis acid–catalyzed addition of diphenyldiselenide to MCPs, reported by us
recently,[3] by employing Yb(OTf)3 as catalyst. However, the products were quite
different from that of the TiCl4-catalyzed reaction. Instead of the ring-enlarged pro-
duct cyclobutane-1,1-diylbis(phenylselane) derivatives, ring-opened product 2,4-
diphenylselenyl-1-butene derivatives 6 were obtained when alkyl-substituted MCPs
were employed (Table 4, entries 1–4). Compared with the reported free radical
additions,[2h,2k] the stereoselectivity was slightly higher when unsymmetric MCPs
Figure 1. Structure of compound 7.

METAL TRIFLATE–CATALYZED BOND CLEAVAGE
1963
were employed (Table 4, entries 1 and 2). When aryl-substituted MCP 5e was
employed, only cyclopropyl ring intact adduct 7 was obtained in 20% yield (entry
5, Table 4; Fig. 1).
In conclusion, we found that, when catalyzed by Yb(OTf)3, diphenyldiselenide
could add to allenes through electrophilic addition, providing a novel and efficient
method for the synthesis of 2,3-diphenylselenyl-1-propene derivatives. The mild con-
ditions, the high regio- and stereoselectivities, and the low dosage of the catalyst are
the advantages. We also found that when Yb(OTf)3 was employed as Lewis acid
catalyst, the products were different from those of the TiCl4-catalyzed addition of diphe-
nyldiselenide to MCPs. The cleavage of Se-Se bond in this novel way under mild con-
ditions will expand the view of organic synthesis and facilitate new synthetic strategies.
EXPERIMENTAL
1H NMR spectra were recorded on a Bruker Avance (600-MHz) spectrometer
in CDCl3 with tetramethylsilane (TMS) as the internal standard. 13C NMR spectra
were recorded on a Bruker Avance (150 MHz) spectrometer in CDCl3. Infrared (IR)
spectra were recorded on a Shimadzu IR-408 spectrometer. Electron impact mass
spectrometry (EIMS) was run on an HP 5989B mass spectrometer.
General Procedure for the Yb(OTf)3-Catalyzed Additions of
Diphenyldiselenide to Allenes
In a Schlenk tube, 0.24 mmol of 1, 0.2 mmol of diphenyldiselenide (62.4 mg),
0.01 mmol of Yb(OTf)3 (5%, 6.2 mg), and 1 mL of 1,2-dichloroethane (DCE) were
added. The mixture was stirred at 60 ꢁC under a nitrogen atmosphere and was mon-
itored by thin-layer chromatography (TLC; eluent: petroleum ether). When the reac-
tion terminated, the solvent was evaporated under vacuum. The residue was isolated
by preparative TLC (eluent: petroleum ether=EtOAC 20:1) to give the corresponding
adduct 2.
General Procedure for the Yb(OTf)3-Catalyzed Additions of
Diphenyldiselenide to MCPs
In a Schlenk tube, 0.24 mmol of 5, 0.2 mmol of diphenyldiselenide (62.4 mg),
0.01 mmol of Yb(OTf)3 (5%, 6.2 mg), and 1 mL of DCE were added. The mixture
was stirred at room temperature under a nitrogen atmosphere and was monitored
by TLC (eluent: petroleum ether). When the reaction terminated, the solvent was
evaporated under vacuum. The residue was isolated by preparative TLC (eluent: pet-
roleum ether=EtOAC 12:1) to give the corresponding adduct 6 (for substrate 5a–5d)
or 7 (for substrate 5e).
Data
Compound 2a. Oil. IR (film): 3055, 1637, 1578, 1476, 1438, 1022, 913, 738,
1
691 cmꢀ1. H NMR (600 MHz, CDCl3, TMS): d 7.22–7.55 (m, 15H), 6.68 (s, 1H),
3.73 (s, 2H). 13C NMR (150 MHz, CDCl3): d 38.3, 127.5, 127.6, 127.9, 128.0,

1964
L. YU ET AL.
128.6, 128.9(d), 129.2, 129.9, 131.2, 133.5,134.6, 134.7, 137.0. MS (apci): m=z (%) 430
(8) [Mþ], 390 (100), 273 (14) [Mþ-PhSe].
Compound 2b. Oil. IR (film): 3055, 1657, 1578, 1507, 1475, 1437, 1388, 1067,
1021, 999, 800, 780, 737, 691 cmꢀ1. 1H NMR (600 MHz, CDCl3, TMS): (Z isomer) d
7.05–7.82 (m, 18H), 3.86 (s, 2H). (E isomer) d7.05–7.82 (m, 18H), 3.94 (s, 2H). 13C
NMR (150 MHz, CDCl3): (Z and E mixtures) d 32.2, 36.9, 124.7(d), 125.1, 125.3,
125.8, 126.0, 126.2, 126.9, 127.3, 127.7, 127.9, 128.0, 128.1, 128.4, 128.9, 129.1,
129.5, 131.4, 133.2, 133.6, 134.2, 134.5, 134.7, 134.9. MS (EI, 70 eV): m=z (%) 480
(3) [Mþ], 323 (25) [Mþ-PhSe], 165 (100). Anal. calcd. for C25H20Se2: C, 62.77; H,
4.21. Found: C, 62.50; H, 4.53.
Compound 2c. Oil. IR (film): 3058, 3026, 2976, 2925, 1476, 1437, 1180, 1121,
1
1069, 1022, 736, 692 cmꢀ1. H NMR (600 MHz, CDCl3, TMS): d 7.00–7.48 (m,
15H), 5.92 (t, J ¼ 6.6 Hz, 1H), 3.73 (s, 2H), 3.569 (d, J ¼ 6.6 Hz, 2H). 13C NMR
(150 MHz, CDCl3): d 37.8, 38.4, 126.1, 127.2, 127.4, 128.3, 128.4, 128.5(d), 128.9,
129.0, 129.2, 129.3, 132.8, 134.2, 136.3. MS (EI, 70 eV): m=z (%) 444 (3) [Mþ], 286
(16) [Mþ-PhSe-1], 129 (100).
Compound 2d. Oil. IR (film): 3057, 2976, 2924, 2860, 1578, 1475, 1440, 1411,
1120, 1069, 1022, 736, 690 cmꢀ1. 1H NMR (600 MHz, CDCl3, TMS): d7.24–7.45 (m,
10H), 5.54 (d, J ¼ 9.0 Hz, 1H), 3.63 (s, 2H), 2.47–2.48 (m, 1H), 0.95–1.63 (m, 10H).
13C NMR (150 MHz, CDCl3): d 25.6, 25.9, 32.5, 37.9, 41.0, 126.5, 127.0, 127.4,
128.8, 129.0, 129.2, 132.3, 132.7, 134.6, 144.1. MS (EI, 70 eV): m=z (%) 436 (6)
[Mþ], 279 (18) [Mþ-PhSe], 79 (100).
Compound 2e. Oil. IR (film): 3057, 2955, 2926, 2855, 1578, 1475, 1437, 1067,
1
1022, 999, 736, 690, 669 cmꢀ1. H NMR (600 MHz, CDCl3, TMS): d 7.24–7.47 (m,
10H), 5.76 (t, J ¼ 6.0 Hz, 1H), 3.69 (s, 2H), 0.85–2.19 (m, 11H). 13C NMR (150 MHz,
CDCl3): d 14.0, 22.5, 28.7, 31.3, 32.0, 38.0, 126.9, 127.3, 128.8, 128.9, 129.1, 132.6,
132.7, 134.1, 134.6, 138.6. MS (apci): m=z (%) 425 (100) [Mþ þ 1], 424 (50) [Mþ].
Anal. calcd. for C20H24Se2: C, 56.88; H, 5.73. Found: C, 57.13; H, 5.44.
Compound 2f. Oil. IR (film): 3055, 2978, 2867, 1578, 1476, 1440, 1383, 1123,
1073, 1022, 1000, 763, 737, 697 cmꢀ1 1H NMR (600 MHz, CDCl3, TMS): d
.
6.98–7.52 (m, 20H), 3.87 (s, 2H). 13C NMR (150 MHz, CDCl3): d 34.1, 127.1,
127.3, 127.4, 127.6, 127.8, 128.1, 128.8, 129.0, 129.2(d), 129.3, 129.7, 130.1, 131.0,
134.4, 141.1, 143.0, 146.6. MS (EI, 70 eV): m=z (%) 506 (1) [Mþ], 349 (27) [Mþ-PhSe],
192 (100). Anal. calcd. for C27H22Se2: C, 64.29; H, 4.40. Found: C, 63.94; H, 4.57.
Compound 2g. Oil. IR (film): 3056, 2967, 2930, 2871, 1577, 1476, 1438, 1381,
1180, 1069, 1022, 765, 737, 695 cmꢀ1 1H NMR (600 MHz, CDCl3, TMS): d
.
6.96–7.52 (m, 15H), 3.66 (s, 2H), 2.71 (q, J ¼ 7.2 Hz, 2H), 0.85 (t, J ¼ 7.2 Hz, 3H).
13C NMR (150 MHz, CDCl3): d 12.6, 32.8, 35.4, 126.4, 127.0(d), 127.1, 128.1,
128.2, 128.8, 129.2, 130.5, 130.7, 132.5, 134.0, 140.7, 150.9. MS (EI, 70 eV): m=z
(%) 458 (3) [Mþ], 301 (24) [Mþ-PhSe], 143 (100). Anal. calcd. for C23H22Se2: C,
60.54; H, 4.86. Found: C, 60.37; H, 4.60.
Compound 2h. Oil. IR (film): 3055, 2926, 2851, 2361, 2338, 1640, 1577, 1475,
1
1440, 1384, 1069, 1022, 976, 913, 774, 737, 691 cmꢀ1. H NMR (600 MHz, CDCl3,

METAL TRIFLATE–CATALYZED BOND CLEAVAGE
1965
TMS): d6.76–7.54 (m, 15H), 3.48 (s, 2H), 3.16 (t, J ¼ 12 Hz, 1H), 1.53–1.65 (m, 6H),
1.23–1.28 (m, 2H), 0.90–0.96 (m, 2H). 13C NMR (150 MHz, CDCl3): d 27.0, 27.5,
32.8, 36.6, 47.3, 128.0, 128.1, 128.3, 128.4, 129.0, 130.0(d), 130.4, 131.7, 132.1,
134.0, 135.5, 140.1, 155.0. MS (EI, 70 eV): m=z (%) 512 (4) [Mþ], 355 (36) [Mþ-PhSe],
115 (100). Anal. calcd. for C27H28Se2: C, 63.53; H, 5.53. Found: C, 63.38; H, 5.27.
Compound 6a. Oil. IR (film): 2925, 2863, 1636, 1579, 1475, 1438, 1383, 1069,
1022, 735, 691 cmꢀ1. 1H NMR (600 MHz, CDCl3, TMS): (E isomer) d 7.19–7.42 (m,
10H), 6.07 (t, J ¼ 7.5 Hz, 1H), 3.03 (t, J ¼ 8.4 Hz, 2H), 2.58–2.63 (m, 2H), 2.02–2.04
(m, 2H), 0.86–1.38 (m, 13H); (Z isomer) d 7.19–7.42 (m, 10H), 5.90 (t, J ¼ 6.9 Hz,
1H), 3.04 (t, J ¼ 7.2 Hz, 2H), 2.58–2.63 (m, 2H), 2.28–2.31 (m, 2H), 0.86–1.38 (m,
13H). 13C NMR (150 MHz, CDCl3): (E and Z mixture) d 14.1, 18.2, 22.7, 26.3,
27.0, 28.5, 29.1, 29.2(d), 29.3, 29.4(d), 29.6, 31.8, 31.9, 33.5, 36.1, 39.9, 126.6,
126.7(d), 126.9, 128.8, 128.9, 129.0(d), 129.1, 130.0, 130.2, 130.6, 131.2, 132.2,
132.3(d), 133.8, 134.5, 137.9, 140.7. MS (EI, 70 eV): m=z (%) 466 (12) [Mþ], 309
(45) [Mþ-PhSe], 67 (100). Anal. calcd. for C23H30Se2: C, 59.48; H, 6.51. Found: C,
59.17; H, 6.26.
Compound 6b. Oil. IR (film): 3070, 2924, 2853, 1579, 1475, 1437, 1144, 1070,
1
1022, 1000, 735, 691, 669 cmꢀ1. H NMR (600 MHz, CDCl3, TMS): (E isomer) d
7.19–7.41 (m, 10H), 6.06 (t, J ¼ 7.5 Hz, 1H), 3.01–3.04 (m, 2H), 2.59–2.63 (m, 2H),
2.01–2.05 (m, 2H), 1.26–1.36 (m, 14H), 0.86–0.90 (m, 3H). (Z isomer) d 7.19–7.41
(m, 10H), 5.89 (t, J ¼ 6.9 Hz, 1H), 3.01–3.04 (m, 2H), 2.59–2.63 (m, 2H), 2.29–2.31
(m, 2H), 1.26–1.36 (m, 14H), 0.86–0.90 (m, 3H). 13C NMR (150 MHz, CDCl3): (E
and Z mixture) d 14.1, 18.2, 22.7, 26.3, 27.0, 28.4, 29.2, 29.3(d), 29.4, 29.5(d),
29.6(d), 31.9, 33.5, 36.1, 39.9, 126.5, 126.6, 126.7, 126.9, 128.8, 128.9(d), 129.0,
129.1, 130.0, 130.2, 130.5, 131.2, 132.2(d), 132.3, 133.8, 134.5, 137.9, 140.7. MS
(EI, 70 eV): m=z (%) 494 (9) [Mþ], 337 (45) [Mþ-PhSe], 67 (100). Anal. calcd. for
C25H34Se2: C, 60.97; H, 6.96. Found: C, 60.79; H, 6.73.
Compound 6c. Oil. IR (film): 3069, 2926, 2851, 1578, 1476, 1438, 1384, 1022,
1
998, 734, 690, 669 cmꢀ1. H NMR (600 MHz, CDCl3, TMS): d 7.20–7.42 (m, 10H),
3.03 (t, J ¼ 7.8 Hz, 2H), 2.74 (t, J ¼ 7.8 Hz, 2H), 2.56 (t, J ¼ 5.7 Hz, 2H), 2.27 (t,
J ¼ 5.7 Hz, 2H), 1.56–1.57 (m, 6H). 13C NMR (150 MHz, CDCl3): d 26.6, 26.7,
28.3, 28.4, 31.3, 35.8, 36.2, 121.8, 126.2, 126.5, 129.0, 129.1, 130.5, 131.0, 132.0,
132.1, 148.9. MS (EI, 70 eV): m=z (%) 436 (11) [Mþ], 279 (45) [Mþ-PhSe], 79 (100).
Compound 6d. Oil. IR (film): 3058, 2924, 2853, 1631, 1579, 1476, 1437, 1384,
1
1119, 1068, 1022, 1000, 735, 693, 668 cmꢀ1. H NMR (600 MHz, CDCl3, TMS):
d7.20–7.44 (m, 15H), 3.36–3.38 (m, 1H), 3.06 (t, J ¼ 7.2 Hz, 2H), 2.72–2.82 (m,
4H), 1.99–2.12 (m, 4H), 1.51–1.55 (m, 2H). 13C NMR (150 MHz, CDCl3): d 26.8,
30.9, 35.3, 35.5, 35.8, 35.9, 44.4, 122.8, 126.2, 126.3, 126.6, 126.8, 128.4, 129.0,
129.1, 130.4, 131.3, 131.8, 132.2, 146.3, 147.2. MS (EI, 70 eV): m=z (%) 512 (7)
[Mþ], 355 (27) [Mþ-PhSe], 91 (100).
Compound 7. Oil. IR (film): 1638, 1479, 1436, 1385, 1134, 1070, 1015, 913,
1
740, 691. H NMR (600 MHz, CDCl3, TMS): d 7.15–7.34 (m, 14H), 4.55 (s, 1H),
1.13–1.39 (m, 4H). 13C NMR (150 MHz, CDCl3): (E and Z mixture) d 14.5, 15.6,
27.1, 56.3, 121.0, 127.3, 127.4, 128.7, 128.9, 129.0, 130.1, 130.3, 131.3, 133.3,

1966
L. YU ET AL.
133.5, 140.8. MS (EI, 70 eV): m=z (%) 522 (2) [Mþ], 365 (29) [Mþ-PhSe], 128 (100).
HRMS (ESI): m=z calcd. for C22H19BrNaSe2 (M þ Na)þ 544.8898, Found 544.8885.
ACKNOWLEDGMENTS
This work was supported by the University Natural Scientific Foundation of
Jiangsu Province (No. 09KJB150014), the 45th Postdoctoral Foundation of China
(No. 20090451249), and the National Natural Scientific Foundation of China
(Nos. 20633010 and 20773106).
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