Facile synthesis of (S,S)-1,2-diacylamides and (S,S)-1,2-diamines with C2-symmetry

Article abstract of DOI:10.1080/00397910600770698

A series of chiral vicinal tertiary diacylamides with C₂- symmetry was synthesized from (S)-α-phenylethylamine, different aromatic aldehydes, and oxalyl chloride. The diacylamides obtained were then reduced to afford chiral vicinal diamines wit

Full text of DOI:10.1080/00397910600770698

Synthetic Communicationsw, 36: 2859–2875, 2006
Copyright # Taylor & Francis Group, LLC
ISSN 0039-7911 print/1532-2432 online
DOI: 10.1080/00397910600770698
Facile Synthesis of (S,S)-1,2-Diacylamides
and (S,S)-1,2-Diamines with C2-Symmetry
Lin Ai, Jichuan Xiao, Guo Wang, Xiumin Shen,
and Cong Zhang
Department of Chemistry, Beijing Normal University, Beijing, China
Abstract: A series of chiral vicinal tertiary diacylamides with C2-symmetry was syn-
thesized from (S)-a-phenylethylamine, different aromatic aldehydes, and oxalyl
chloride. The diacylamides obtained were then reduced to afford chiral vicinal
diamines with C2-symmetry. We propose that the diacylamides existed in four stable
conformational isomers in solution because of the dihedral angle between acylamide
bonds.
Keywords: (S,S)-1,2-Diacylamides, (S,S)-1,2-diamines, C2-symmetry, synthesis
Chiral vicinal diamines, as important parts in organic synthesis, have been
widely used in medicinal chemistry[1] and asymmetric synthesis,[2] especially
as chiral ligands or chiral auxiliaries in various kinds of asymmetric reactions
such as Mukaiyama aldol reactions,[3] Mannich-type reactions,[4] Michael
additions,[5] Sharpless dihydroxylation,[6] chiral Lewis acid–based
reactions,[7] acylation of alcohols,[8] hydrogenation of ketones,[9] protonation
of enolates,[10] enantioselective addition reaction of organometallics,[11]
conjugate addition,[12] desymmetrization of meso ketones,[13] epoxides,[14]
asymmetric cyclopropanation of styrene,[15] and so on. Therefore, design
and synthesis of new chiral ligands for the enantioselective reaction is an
important goal in chemical synthesis.[16] In addition, diacylamides have indus-
trial uses as synthetic intermediates.[17] Some of them show biological activity
as pesticides.[18]
Received in R.O.C. December 2, 2005
Address correspondence to Cong Zhang, Department of Chemistry, Beijing Normal
University, Beijing 100875, China. E-mail: czhang@bnu.edu.cn
2859

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L. Ai et al.
Scheme 1. Synthesis of (S,S)-1,2-diacylamides 5.
In this article, a series of chiral diacylamides and diamines with C2-
symmetry was designed and synthesized starting from commercially
available (S)-a-phenylethylamine, different aromatic aldehydes, and oxalyl
chloride. At the same time, the possible conformations of (S,S)-1,2-diacyla-
mides were discussed.
(S,S)-1,2-Diacylamides 5 were synthesized starting from (S)-a-pheny-
lethylamine, the appropriate aromatic aldehydes, and oxalyl chloride in
three steps as shown in Scheme 1.
The isolated yields and [a]2D5 data of compounds 5a–m are summarized in
Table 1.
1
Interestingly, H NMR (500 MHz) and 13C NMR (125 MHz) spectra of
the diacylamides synthesized exhibited three or four sets of signals for the
Table 1. Yields and optical rotation data for compounds 5a–5m
Entry
Compound
Ar
Yielda (%)
[a]2D5
1
2
5a
5b
78
80
2130 (c 0.69 THF)
2156 (c 0.59 THF)
3
4
5c
5d
5e
5f
C6H5
81
59
77
81
72
83
76
62
61
89
47
2152 (c 0.54 THF)
256 (c 0.69 THF)
266 (c 0.67 THF)
2105 (c 0.67 THF)
2115 (c 0.91 THF)
2107 (c 0.82 THF)
2124 (c 0.65 THF)
2109 (c 0.96 THF)
2109 (c 0.85 THF)
2140 (c 0.52 THF)
2101 (c 0.62 THF)
o-O2NC6H5
m-O2NC6H5
p-O2NC6H5
o-ClC6H5
5
6
7
5g
5h
5i
8
m-ClC6H5
p-ClC6H5
9
10
11
12
13
5j
o-CH3OC6H5
m-CH3OC6H5
p-CH3OC6H5
C6H5CH55CH
5k
5l
5m
aIsolated yields.

Facile Synthesis with C2-Symmetry
2861
Figure 1. 1H NMR (500 MHz) spectrum of chiral vicinal tertiary diacylamide 5i.
same hydrogen atoms and carbon atoms of the methyl, methene, and methenyl
1
groups, respectively. H NMR (500 MHz) and 13C NMR (125 MHz) spectra
of the diacylamide 5i are shown in Figs. 1 and 2.
Based on the elemental analysis data, mass spectral data or high-
resolution mass spectral data, and melting point, each of diacylamides was
Figure 2. 13C NMR (125-MHz) spectrum of chiral vicinal tertiary diacylamide 5i.

2862
L. Ai et al.
Figure 3. Structure of diacylamide 5j.
identified as a pure component. Moreover, a series of chiral vicinal diamines
were obtained in good yields by reduction of the chiral diacylamides. To
verify these interesting results, simulated annealings with molecular
dynamics were performed and conformations were optimized using the
B3LYP[19] method at the 6-31G(d) level with the GAUSSIAN03 program
for diacylamide 5j.[20] The structure of diacylamide 5j is shown in Fig. 3.
The four stable conformational isomers (5j-a, 5j-b, 5j-c, 5j-d) and the
corresponding energies relative to each other are shown in Fig. 4.
In addition, by careful recrystallization, the crystal of compound 5j was
obtained from n-hexane/ethyl ether (50/1) for the purpose of X-ray crystal
structure analysis, but the crystal of other compounds in this series could
not be obtained. The X-ray structure of compound 5j confirms that it is the
most stable conformational isomer in solid, and the dihedral angle between
acylamide bonds was almost 908, as shown in Fig. 5.
Figure 4. Four stable conformational isomers of compound 5j.

Facile Synthesis with C2-Symmetry
2863
Figure 5. ORTEP and packing diagram of compound 5j.
According to the simulated and optimized results and crystal structure
analysis of vicinal diacylamide 5j, the conformational isomer of compound
5j-a is the most stable. The structure parameters of 5j-a agree very well with
the X-ray diffraction data of compound 5j. The structure of conformational
isomer 5j-a is similar to the crystal structure of compound 5j to a great extent.
Chiral vicinal (S,S)-1,2-diamines 6 were prepared from corresponding
diacylamides 5 by the following reduction procedures with LiAlH4 or
.
BH3 SMe2 in THF in good yields as shown in Scheme 2.
The isolated yields and [a]2D5 data of compounds 6a–m are summarized in
Table 2.
In summary, a facile synthesis has been developed to obtain chiral vicinal
diamines starting from very cheap and easily available materials under mild
reaction conditions. The four stable conformational isomers of (S,S)-1,2-
diacylamides were described. Further investigation is in progress.
EXPERIMENTAL
Melting points were measured with a X-4 melting-point apparatus and are
uncorrected. IR spectra were recorded in KBr disks with an Avatar 360 FT-
IR infrared spectrometer and are expressed in centimeters21 1H NMR
.
(500 MHz) and 13C NMR (125 MHz) spectra were measured on an Avance
Scheme 2. Synthesis of (S,S)-1,2-diamines 6.

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L. Ai et al.
Table 2. Yields and optical rotation data for compounds 6a–6m
Entry
Compound
Ar
Yielda (%)
82b
[a]2D5
1
2
6a
6b
279 (c0.66 THF)
249 (c0.69 THF)
84b
3
4
6c
6d
6e
6f
C6H5
85b
62c
65c
63c
65b
81b
74b
69b
72b
63b
70b
243 (c0.74 THF)
233 (c0.77 THF)
234 (c0.41 THF)
250 (c0.36 THF)
219 (c0.86 THF)
239 (c0.78 THF)
257 (c0.60 THF)
227 (c0.59 THF)
240 (c0.99 THF)
267 (c0.36 THF)
273 (c0.32 THF)
o-O2NC6H5
m-O2NC6H5
p-O2NC6H5
o-ClC6H5
5
6
7
6g
6h
6i
8
m-ClC6H5
p-ClC6H5
9
10
11
12
13
6j
o-CH3OC6H5
m-CH3OC6H5
p-CH3OC6H5
C6H5CH55CH
6k
6l
6m
aIsolated yields; (S,S)-1,2-diamines were prepared from (S,S)-1,2-diacylamides.
bWith LiAlH4 in dry THF.
cWith BH3 SMe2 in dry THF.
.
DRX 500 Bruker spectrometer with CDCl3 as a solvent. Chemical shift values
were given in parts per million (ppm) relative to internal tetramethylsilane
(TMS) as the reference (d ¼ 0 ppm). The multiplicities were expressed as s
(singlet), d (doublet), t (triplet), q (quartet), m (multiplet), or br (broad).
The elemental analyses were determined with a Vario E1 elemental
analyzer. Optical rotations were measured in a Perkin-Elmer Model 343LC
polarmeter using the sodium D line at 589 nm. The crystal was measured
with phi and omega scans at 293(2) K on a Bruker Smart 1000 CCD area
detector diffractometer. Solvents were dried using the standard procedures.
General Procedure for Preparation of Chiral Vicinal
(S,S)-1,2-Diacylamides 5
For example 5a, (S)-a-phenylethylamine (1.27 g, 10.5 mmol) was added
dropwise to a mixture of the furan-2-carbaldehyde (0.96 g, 10.0 mmol) and
anhydrous Na2SO4 (1.0 g) in dry DMF (10.0 mL), and then stirred overnight
at room temperature. The reaction mixture was quenched with H2O (30 mL)
and extracted with EtOAc (3 ꢀ 15 mL). After drying over anhydrous Na2SO4,
the solvent was evaporated in vacuo. The crude product was purified by
column chromatography on silica gel with petroleum ether and ethyl acetate
(3/1) as eluent to afford imine 3a in good yield. NaBH4 (0.81 g, 21.5 mmol)
was added to a solution of compound 3a (1.71 g, 8.6 mmol) in dry methanol–
toluene (25/25 mL), and the reaction mixture was stirred for 3 h at ambient

Facile Synthesis with C2-Symmetry
2865
temperature under a nitrogen atmosphere. Then the reaction mixture was
quenched with saturated NH4Cl (30 mL) and extracted with EtOAc
(3 ꢀ 10 mL). The combined organic layer was dried over anhydrous Na2SO4
and then concentrated in reduced pressure. The residue was purified by
column chromatography on silica gel with petroleum ether and ethyl acetate
(15/1) as eluent to give product 4a. Triethylamine (1.50 mL) and oxalyl
chloride (3.4 mmol) were added dropwise to a stirred solution of amine 4a
(1.37 g, 6.8 mmol) in dichloromethane at 2788C under a nitrogen atmosphere
and then stirred for 20 min at room temperature. The reaction mixture was
quenched with H2O (20 mL) and extracted with CH2Cl2 (3 ꢀ 20 mL). The
combined organic layer was washed successively with 10% HCl (2 ꢀ 10 mL),
saturated NaHCO3 (2 ꢀ 10 mL), and saturated NaCl (2 ꢀ 10 mL), and then
dried over anhydrous Na2SO4. The solvent was removed in reduced pressure,
and the residue was purified by column chromatography on silica gel with
petroleum ether and ethyl acetate (8/1) as eluent to afford (S,S)-1,2-diacyla-
mides 5a in 78% isolated yield in the last step. The crystal of compound 5j
was obtained from n-hexane/ethyl ether (50/1) at ambient temperature.
Data
(S,S)-N,N0-bis-Furan-2-ylmethyl N,N0-bis-(1-phenylethyl)-oxalamide (5a):
1
Mp 136–1378C; Rf ¼ 0.22 (8:1, petroleum ether/ethyl acetate); H NMR
(500 MHz, CDCl3): d 1.50, 1.54, 1.65 (d, J ¼ 7.00 Hz, d, J ¼ 7.08 Hz, d,
J ¼ 7.16 Hz, 6H, 2 ꢀ CH3), 3.89, 3.93, 4.23, 4.24, 4.42, 4.56, 4.72, 4.81
(d, J ¼ 15.90 Hz, d, J ¼ 15.78 Hz, d, J ¼ 16.58 Hz, d, J ¼ 16.36 Hz, d,
J ¼ 16.58 Hz, d, J ¼ 16.39 Hz, d, J ¼ 15.66 Hz, d, J ¼ 15.73 Hz, 4H,
2 ꢀ CH2), 5.22, 5.27, 5.80, 5.87 (q, J ¼ 7.09 Hz, q, J ¼ 6.98 Hz, q,
J ¼ 7.17 Hz, q, J ¼ 7.15 Hz, 2H, 2 ꢀ CH), 6.06–6.27 (m, 4H, furan-H),
7.23–7.48 (m, 12H, furan-H, aromatic); 13C NMR (125 MHz, CDCl3): d
16.2, 17.7, 18.1, 37.7, 41.5, 41.6, 52.0, 52.2, 56.0, 56.4, 108.2, 108.4, 109.1,
109.6, 110.6, 110.7, 110.8, 127.5, 127.6, 127.7, 128.0, 128.4, 128.5, 128.6,
128.7, 138.8, 138.9, 139.3, 139.4, 141.2, 141.3, 141.9, 142.0, 150.2, 151.0,
164.7, 164.9, 165.0; IR (KBr): 3145, 3057, 2992, 1641, 1498, 1451, 1410,
1389, 1270, 1013, 757, 703 cm21; MS (m/z): 457.19 (Mþ). Anal. calcd. for
C28H28N2O4: C, 73.66; H, 6.18; N, 6.14. Found: C, 73.47; H, 6.05; N, 6.49.
(S,S)-N,N0-bis-(1-Phenylethyl) N,N0-bis-thiophen-2-ylmethyl-oxalamide
(5b): Mp 136–1378C; Rf ¼ 0.25 (8:1, petroleum ether/ethyl acetate);
1H NMR (500 MHz, CDCl3): d 1.43, 1.54, 1.56, 1.67 (d, J ¼ 7.04 Hz, d,
J ¼ 8.59 Hz, d, J ¼ 7.30 Hz, d, J ¼ 7.02 Hz, 6H, 2 ꢀ CH3), 4.18, 4.23,
4.35, 4.45, 4.46, 4.71, 4.74, 4.88 (d, J ¼ 15.27 Hz, d, J ¼ 15.39 Hz, d,
J ¼ 15.36 Hz, d, J ¼ 15.41 Hz, d, J ¼ 16.14 Hz, d, J ¼ 16.07 Hz, d,
J ¼ 15.22 Hz, d, J ¼ 15.37 Hz, 4H, 2 ꢀ CH2), 5.17, 5.38, 5.69, 5.86
(q, J ¼ 7.02 Hz, q, J ¼ 6.98 Hz, q, J ¼ 7.51 Hz, q, J ¼ 7.27 Hz, 2H,

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L. Ai et al.
2 ꢀ CH), 6.67–6.89 (m, 4H, thiophen-H), 7.12–7.53 (m, 12H, thiophen-H,
aromatic); 13C NMR (125 MHz, CDCl3): d 16.8, 16.9, 18.1, 18.8, 40.0,
40.3, 43.8, 43.9, 52.7, 52.8, 56.4, 56.5, 125.4, 125.5, 126.0, 126.1, 126.4,
126.7, 127.6, 127.7, 127.9, 128.0, 128.1, 128.4, 128.7, 138.7, 138.8, 139.8,
141.0, 165.0; IR (KBr): 3104, 3061, 2986, 1642, 1639, 1497, 1452, 1409,
1389, 1267, 1226, 1026, 854, 791, 703 cm21; MS (m/z): 489.20 (Mþ).
Anal. calcd. for C28H28N2O2S2: C, 68.82; H, 5.78; N, 5.73. Found: C,
68.72; H, 5.86; N, 5.86.
(S,S)-N,N0-Dibenzyl N,N0-bis-(1-phenyl ethyl)-oxalamide (5c): Mp 40–
1
418C; Rf ¼ 0.29 (8:1, petroleum ether/ethyl acetate); H NMR (500 MHz,
CDCl3): d 1.37, 1.38, 1.42, 1.62 (d, J ¼ 6.98 Hz, d, J ¼ 7.15 Hz, d,
J ¼ 7.15 Hz, d, J ¼ 6.97 Hz, 6H, 2 ꢀ CH3), 3.95, 4.02, 4.11, 4.28, 4.30,
4.55, 4.81, 4.94 (d, J ¼ 15.34 Hz, d, J ¼ 15.51 Hz, d, J ¼ 15.99 Hz, d,
J ¼ 15.71 Hz, d, J ¼ 15.95 Hz, d, J ¼ 15.77 Hz, d, J ¼ 15.37 Hz, d,
J ¼ 15.51 Hz, 4H, 2 ꢀ CH2), 5.20, 5.40, 5.69, 5.74 (q, J ¼ 7.01 Hz, q,
J ¼ 6.95 Hz, q, J ¼ 7.15 Hz, q, J ¼ 6.75 Hz, 2H, 2 ꢀ CH), 7.10–7.37
(m, 20H, aromatic); 13C NMR (125 MHz, CDCl3): d 16.9, 17.2, 18.6, 19.0,
44.7, 45.1, 49.0, 49.8, 52.5, 53.3, 56.7, 56.9, 127.0, 127.3, 127.5, 127.6,
127.8, 127.9, 128.0, 128.2, 128.3, 128.4, 128.5, 128.7, 136.8, 138.2, 138.3,
139.0, 139.7, 165.5, 165.8, 165.9; IR (KBr): 3088, 3062, 3031, 2980, 2937,
1737, 1633, 1496, 1452, 1410, 1198, 1160, 1078, 1028, 755, 699 cm21; MS
(m/z): 477.19 (Mþ). Anal. calcd. for C32H32N2O2: C, 80.64; H, 6.77; N,
5.88. Found: C, 80.50; H, 7.23, N, 5.72.
(S,S)-N,N0-bis-(2-Nitro-benzyl) N,N0-bis-(1-phenylethyl)-oxalamide (5d):
Mp 82–838C; Rf ¼ 0.38 (3:1, petroleum ether/ethyl acetate); 1H NMR
(500 MHz, CDCl3):
d
1.38, 1.54, 1.55, 1.75 (d, J ¼ 7.15 Hz, d,
J ¼ 7.40 Hz, d, J ¼ 7.23 Hz, d, J ¼ 6.90 Hz, 6H, 2 ꢀ CH3), 4.68, 4.71,
4.82, 4.89, 4.99, 5.09 (d, J ¼ 16.30 Hz, d, J ¼ 16.98 Hz, d, J ¼ 17.69 Hz, d,
J ¼ 17.57 Hz, d, J ¼ 17.73 Hz, d, J ¼ 17.56 Hz, 4H, 2 ꢀ CH2), 5.29, 5.49,
5.73, 5.78 (q, J ¼ 6.95 Hz, q, J ¼ 6.92 Hz, q, J ¼ 7.04 Hz, q, J ¼ 7.16 Hz,
2H, 2 ꢀ CH), 7.10–7.99 (m, 18H, aromatic); 13C NMR (125 MHz, CDCl3):
d 16.9, 17.1, 18.6, 18.7, 41.8, 42.2, 45.2, 45.8, 53.0, 53.8, 56.9, 57.0, 124.8,
124.9, 127.0, 127.2, 127.6, 127.8, 128.2, 128.3, 128.5, 128.7, 128.8, 129.0,
130.7, 133.0, 133.5, 138.1, 138.8, 147.5, 165.9, 166.0, 166.2; IR (KBr):
2980, 1638, 1525, 1496, 1453, 1405, 1341, 1204, 1162, 1028, 728,
701 cm21; MS (m/z): 255.17 (100). Anal. calcd. for C32H30N4O6: C, 67.83;
H, 5.34; N, 9.89. Found: C, 67.74; H, 5.22; N, 9.45.
(S,S)-N,N0-bis-(3-Nitro-benzyl) N,N0-bis-(1-phenylethyl)-oxalamide (5e):
Mp 62–638C; Rf ¼ 0.31 (3:1, petroleum ether/ethyl acetate); 1H NMR
(500 MHz, CDCl3): d 1.38, 1.51, 1.77 (d, J ¼ 7.15 Hz, d, J ¼ 6.91 Hz, d,
J ¼ 6.96 Hz, 6H, 2 ꢀ CH3), 4.34, 4.45, 4.47, 4.50, 4.54, 4.65
(d, J ¼ 15.31 Hz, d, J ¼ 15.29 Hz, d, J ¼ 16.18 Hz, d, J ¼ 15.64 Hz,

Facile Synthesis with C2-Symmetry
2867
d, J ¼ 16.11 Hz, d, J ¼ 15.66 Hz, 4H, 2 ꢀ CH2), 5.30, 5.43, 5.83, 5.97
(q, J ¼ 6.94 Hz, q, J ¼ 6.91 Hz, q, J ¼ 7.04 Hz, q, J ¼ 7.14 Hz, 2H,
2 ꢀ CH), 7.10–8.02 (m, 18H, aromatic); 13C NMR (125 MHz, CDCl3): d
16.7, 16.9, 18.2, 18.6, 44.1, 44.5, 47.8, 48.3, 52.3, 52.7, 56.6, 56.8, 122.0,
122.1, 122.2, 122.8, 122.9, 127.5, 127.6, 127.8, 127.9, 128.3, 128.4, 128.6,
128.7, 128.9, 129.3, 129.4, 133.6, 134.4, 138.1, 138.8, 139.7, 165.5; IR
(KBr): 3066, 2980, 2938, 1636, 1529, 1452, 1408, 1349, 1288, 1202, 1158,
1098, 1028, 793, 731, 700 cm21; MS (m/z): 566.18 (Mþ). Anal. calcd. for
C32H30N4O6: C, 67.83; H, 5.34; N, 9.89. Found: C, 68.08; H, 5.45; N, 9.33.
(S,S)-N,N0-bis-(4-Nitro-benzyl) N,N0-bis-(1-phenylethyl)-oxalamide (5f):
1
Mp 151–1528C; Rf ¼ 0.30 (3:1, petroleum ether/ethyl acetate); H NMR
(500 MHz, CDCl3):
d
1.38, 1.48, 1.51, 1.72 (d, J ¼ 7.17 Hz, d,
J ¼ 7.17 Hz, d, J ¼ 7.00 Hz, d, J ¼ 6.94 Hz, 6H, 2 ꢀ CH3), 4.23, 4.36–
4.41, 4.51, 4.57, 4.74 (d, J ¼ 15.28 Hz, m, d, J ¼ 16.40 Hz, d,
J ¼ 15.89 Hz, d, J ¼ 15.98 Hz, 4H, 2 ꢀ CH2), 5.30, 5.39, 5.79, 5.93
(q, J ¼ 6.97 Hz, q, J ¼ 6.91 Hz, q, J ¼ 7.10 Hz, q, J ¼ 7.16 Hz, 2H,
2 ꢀ CH), 7.10–7.47 (m, 14H, aromatic), 8.00–8.10 (m, 4H, aromatic); 13C
NMR (125 MHz, CDCl3): d 16.9, 17.1, 18.4, 18.7, 44.2, 44.7, 47.9, 48.6,
52.5, 52.9, 56.7, 56.9, 123.5, 123.6, 127.4, 127.5, 127.8, 127.9, 128.0,
128.3, 128.5, 128.6, 128.7, 128.9, 129.0, 138.2, 138.3, 144.1, 145.0, 147.0,
165.3, 165.6, 165.7; IR (KBr): 2974, 1630, 1601, 1520, 1410, 1344, 1155,
1110, 1030, 796, 751, 700 cm21; MS (m/z): 566.13 (Mþ). Anal. calcd. for
C32H30N4O6: C, 67.83; H, 5.34; N, 9.89. Found: C, 67.95; H, 5.31; N, 9.73.
(S,S)-N,N0-bis-(2-Chloro-benzyl) N,N0-bis-(1-phenylethyl)-oxalamide (5g):
Mp 64–658C; Rf ¼ 0.26 (8:1, petroleum ether/ethyl acetate); 1H NMR
(500 MHz, CDCl3): d 1.39, 1.42, 1.58, 1.68 (d, J ¼ 7.23 Hz, d, J ¼ 7.01 Hz,
d, J ¼ 7.23 Hz, d, J ¼ 6.95 Hz, 6H, 2 ꢀ CH3), 4.33, 4.36, 4.79, 4.92
(d, J ¼ 16.80 Hz, d, J ¼ 17.36 Hz, s, d, J ¼ 16.66 Hz, d, J ¼ 16.71 Hz, 4H,
2 ꢀ CH2), 5.19, 5.48, 5.68, 5.75 (q, J ¼ 6.99 Hz, q, J ¼ 6.92 Hz, q,
J ¼ 7.00 Hz, q, J ¼ 7.19 Hz, 2H, 2 ꢀ CH), 7.16–7.65 (m, 18H, aromatic);
13C NMR (125 MHz, CDCl3): d 16.9, 17.3, 18.5, 42.0, 42.6, 45.6, 46.5, 52.6,
53.9, 56.7, 57.0, 126.9, 127.2, 127.7, 127.9, 128.0, 128.1, 128.5, 128.7, 128.8,
129.1, 129.2, 130.0, 134.6, 138.8, 140.0, 165.7, 165.8, 166.0, 166.2; IR (KBr):
3064, 2979, 1638, 1496, 1444, 1407, 1278, 1200, 1164, 1050, 1049, 751,
699 cm21; MS (m/z): 545.30 (Mþ). Anal. calcd. for C32H30Cl2N2O2: C,
70.46; H, 5.54; N, 5.14. Found: C, 70.88; H, 5.78; N, 4.88.
(S,S)-N,N0-bis-(3-Chloro-benzyl) N,N0-bis-(1-phenylethyl)-oxalamide (5h):
1
Mp 127–1288C; Rf ¼ 0.26 (10:1, petroleum ether/ethyl acetate); H NMR
(500 MHz, CDCl3):
d
1.39, 1.40, 1.51, 1.68 (d, J ¼ 7.11 Hz, d,
J ¼ 6.90 Hz, d, J ¼ 7.16 Hz, d, J ¼ 6.95 Hz, 6H, 2 ꢀ CH3), 4.08, 4.13,
4.17, 4.28, 4.30, 4.46, 4.59, 4.74 (d, J ¼ 15.45 Hz, d, J ¼ 17.48 Hz, d,
J ¼ 15.79 Hz, d, J ¼ 16.21 Hz, d, J ¼ 16.06 Hz, d, J ¼ 16.25 Hz,

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L. Ai et al.
d, J ¼ 15.46 Hz, d, J ¼ 15.54 Hz, 4H, 2 ꢀ CH2), 5.20, 5.36, 5.75, 5.84
(q, J ¼ 6.98 Hz, q, J ¼ 6.86 Hz, 2H, q, J ¼ 7.12 Hz, q, J ¼ 7.07 Hz, 2H,
2 ꢀ CH), 6.96–7.35 (m, 18H, aromatic); 13C NMR (125 MHz, CDCl3): d
16.7, 17.1, 18.3, 18.8, 44.2, 44.6, 48.2, 48.8, 52.4, 53.1, 56.6, 56.8, 125.6,
127.1, 127.2, 127.5, 127.6, 127.8, 128.0, 128.1, 128.2, 128.3, 128.5, 128.6,
128.7, 128.8, 129.7, 129.8, 138.6, 140.0, 165.6; IR (KBr): 3065, 3032,
2981, 2941, 1641, 1632, 1453, 1402, 1317, 1208, 1152, 946, 781, 763, 730,
701 cm21; MS (m/z): 545.19 (Mþ). Anal. calcd. for C32H30Cl2N2O2: C,
70.46; H, 5.54; N, 5.14. Found: C, 70.32; H, 5.63; N, 5.00.
(S,S)-N,N0-bis-(4-Chloro-benzyl) N,N0-bis-(1-phenylethyl)-oxalamide (5i):
Mp 56–578C; Rf ¼ 0.26 (8:1, petroleum ether/ethyl acetate); 1H NMR
(500 MHz, CDCl3):
d
1.38, 1.42, 1.45, 1.64 (d, J ¼ 7.18 Hz, d,
J ¼ 7.03 Hz, d, J ¼ 7.15 Hz, d, J ¼ 6.96 Hz, 6H, 2 ꢀ CH3), 4.04, 4.05,
4.08, 4.21, 4.25, 4.44, 4.62, 4.78 (d, J ¼ 15.42 Hz, d, J ¼ 13.59 Hz, d,
J ¼ 15.43 Hz, d, J ¼ 15.90 Hz, d, J ¼ 16.11 Hz, d, J ¼ 15.86 Hz, d,
J ¼ 15.39 Hz, d, J ¼ 15.50 Hz, 4H, 2 ꢀ CH2), 5.19, 5.34, 5.72, 5.80
(q, J ¼ 7.00 Hz, q, J ¼ 6.93 Hz, q, J ¼ 7.12 Hz, q, J ¼ 6.96 Hz, 2H,
2 ꢀ CH), 6.99–7.35 (m, 18H, aromatic); 13C NMR (125 MHz, CDCl3): d
16.9, 17.2, 18.5, 18.6, 44.1, 44.5, 48.1, 48.8, 52.5, 53.0, 56.6, 56.9,
127.4, 127.6, 127.8, 128.0, 128.1, 128.4, 128.5, 128.6, 128.7, 128.8,
129.0, 129.5, 129.7, 132.8, 136.5, 138.7, 165.3, 165.5, 165.8; IR
(KBr): 3063, 3031, 2980, 2937, 1636, 1492, 1405, 1199, 1159, 1091,
1015, 789, 755, 700 cm21; MS (m/z): 244.17 (100). Anal. calcd. for
C32H30Cl2N2O2: C, 70.46; H, 5.54; N, 5.14. Found: C, 70.25; H, 5.41;
N, 5.37.
(S,S)-N,N0-bis-(2-Methoxy-benzyl) N,N0-bis-(1-phenylethyl)-oxalamide (5j):
1
Mp 105–1068C; Rf ¼ 0.23 (5:1, petroleum ether/ethyl acetate); H NMR
(500 MHz, CDCl3):
d
1.36, 1.40, 1.54, 1.63 (d, J ¼ 6.97 Hz, d,
J ¼ 7.20 Hz, d, J ¼ 7.20 Hz, d, J ¼ 6.96 Hz, 6H, 2 ꢀ CH3), 3.67, 3.75, 3.78
(3s, 6H, 2 ꢀ OCH3), 4.09, 4.19, 4.36, 4.57, 4.78, 4.88 (d, J ¼ 16.26 Hz, d,
J ¼ 16.40 Hz, s, s, d, J ¼ 16.21 Hz, d, J ¼ 16.40 Hz, 4H, 2 ꢀ CH2), 5.14,
5.45, 5.96–5.67 (q, J ¼ 7.01 Hz, q, J ¼ 6.88 Hz, m, 2H, 2 ꢀ CH), 6.72–
7.35 (m, 18H, aromatic); 13C NMR (125 MHz, CDCl3): d 16.8, 17.2, 18.0,
18.4, 39.0, 39.5, 43.3, 43.7, 52.6, 53.7, 55.0, 55.1, 55.2, 56.5, 56.7, 109.7,
109.8, 120.4, 120.5, 120.7, 127.4, 127.5, 127.6, 127.7, 127.8, 128.1, 128.2,
128.3, 128.4, 128.5, 128.6, 129.8, 139.3, 140.2, 140.4, 156.3, 165.8, 165.9,
166.1, 166.4; IR (KBr): 3063, 3031, 2985, 2939, 2837, 1738, 1651, 1603,
1494, 1463, 1410, 1290, 1243, 1162, 1112, 754, 700 cm21; MS (m/z):
537.07 (Mþ). Anal. calcd. for C34H36N2O4: C, 76.09; H, 6.76; N, 5.22.
Found: C, 76.11; H, 6.77; N, 5.20.
(S,S)-N,N0-bis-(3-Methoxy-benzyl) N,N0-bis-(1-phenylethyl)-oxalamide (5k):
1
Mp 133–1348C; Rf ¼ 0.23 (6:1, petroleum ether/ethyl acetate); H NMR

Facile Synthesis with C2-Symmetry
2869
(500 MHz, CDCl3); d 1.38, 1.40, 1.47, 1.64 (d, J ¼ 7.11 Hz, d, J ¼ 7.26 Hz, d,
J ¼ 7.10 Hz, d, J ¼ 7.00 Hz, 6H, 2 ꢀ CH3), 3.55, 3.68, 3.78, 3.79 (4s, 6H,
2 ꢀ OCH3), 3.87, 4.00, 4.08, 4.21, 4.29, 4.54, 4.83, 4.91 (d, J ¼ 15.37 Hz,
d, J ¼ 15.52 Hz, d, J ¼ 15.98 Hz, d, J ¼ 15.82 Hz, d, J ¼ 16.02 Hz, d,
J ¼ 15.77 Hz, d, J ¼ 15.37 Hz, d, J ¼ 15.52 Hz, 4H, 2 ꢀ CH2), 5.18, 5.40,
5.73, 5.79 (q, J ¼ 6.97 Hz, q, J ¼ 6.91 Hz, q, J ¼ 7.11 Hz, q, J ¼ 7.14 Hz,
2H, 2 ꢀ CH), 6.69–7.40 (m, 18H, aromatic); 13C NMR (125 MHz, CDCl3):
d 16.9, 17.3, 18.5, 18.9, 44.6,45.0, 48.9, 49.5, 52.4, 53.1, 54.9, 55.1, 55.3,
56.7, 56.9, 112.4, 113.0, 113.3, 113.4, 114.0, 119.6, 120.6, 127.5, 127.7,
127.9, 128.1, 128.4, 128.5, 128.7, 129.3, 129.4, 129.5, 138.4, 138.6, 139.9,
140.1, 159.6, 159.7, 159.8, 165.6, 165.8, 165.9; IR (KBr): 3035,
2961, 2941, 2839, 1643, 1600, 1494, 1466, 1439, 1358, 1264, 1244, 1208,
1167, 1080, 1035, 782, 751, 699 cm21; MS (m/z): 536.25 (Mþ). Anal.
calcd. for C34H36N2O4: C, 76.09; H, 6.76; N, 5.22. Found: C, 75.83; H,
6.64; N, 5.08.
(S,S)-N,N0-bis-(4-Methoxy-benzyl) N,N0-bis-(1-phenylethyl)-oxalamide (5l):
Mp 51–528C. Rf ¼ 0.22 (5:1, petroleum ether/ethyl acetate); 1H NMR
(500 MHz, CDCl3): d 1.39, 1.44, 1.61 (d, J ¼ 6.81 Hz, d, J ¼ 6.28 Hz, d,
J ¼ 6.80 Hz, 6H, 2 ꢀ CH3), 3.75, 3.78, 3.83 (3s, 6H, 2 ꢀ OCH3), 3.88,
3.94, 4.01, 4.16, 4.26, 4.48, 4.76, 4.87 (d, J ¼ 15.11 Hz, d, J ¼ 15.27 Hz,
d, J ¼ 15.71 Hz, d, J ¼ 14.43 Hz, d, J ¼ 15.72 Hz, d, J ¼ 15.45 Hz, d,
J ¼ 15.11 Hz, d, J ¼ 15.22 Hz, 4H, 2 ꢀ CH2), 5.17, 5.35, 5.68–5.73
(q, J ¼ 6.70 Hz, q, J ¼ 6.78 Hz, m, 2H, 2 ꢀ CH), 6.69–7.37 (m, 18H,
aromatic); 13C NMR (125 MHz, CDCl3): d 17.0, 17.2, 18.6, 19.0, 44.0,
44.5, 48.4, 49.2, 52.4, 53.0, 55.2, 55.3, 56.6, 56.8, 113.7, 113.8, 113.9,
127.6, 127.7, 127.8, 128.0, 128.4, 128.5, 128.6, 128.7, 128.8, 129.1, 129.6,
129.8, 130.5, 139.1, 158.6, 159.2, 159.3, 165.5, 165.7, 165.8, 165.9; IR
(KBr): 3060, 3030, 2935, 2835, 1635, 1513, 1453, 1408, 1302, 1247,
1176, 1111, 1029, 790, 754, 699 cm21; MS (m/z): 535.42 (Mþ). Anal.
calcd. for C34H36N2O4: C, 76.09; H, 6.76; N, 5.22. Found: C, 75.91; H,
6.44; N, 4.97.
(S,S)-N,N0-bis-(3-Phenyl-allyl) N,N0-bis-(1-phenylethyl)-oxalamide (5m):
1
Mp 143–1448C; Rf ¼ 0.27 (6:1, petroleum ether/ethyl acetate); H NMR
(500 MHz, CDCl3);
d
1.62, 1.63, 1.70, 1.81 (d, J ¼ 6.72 Hz, d,
J ¼ 6.71 Hz, d, J ¼ 7.07 Hz, d, J ¼ 6.86 Hz, 6H, 2 ꢀ CH3), 3.72–4.10
(m, 4H, 2 ꢀ CH2), 5.22, 5.31, 5.90–6.31 (q, J ¼ 6.84 Hz, q, J ¼ 6.85 Hz,
m, 6H, 2 ꢀ CH, 4 ꢀ CH55), 7.17–7.40 (m, 20H, CH55 aromatic); 13C
,
NMR (125 MHz, CDCl3): d 16.7, 16.9, 18.3, 18.9, 43.8, 44.1, 47.0, 47.3,
51.5, 51.7, 56.4, 124.9, 126.0, 126.5, 126.6, 127.6, 127.8, 127.9, 128.0,
128.5, 128.6, 128.7, 132.8, 136.2, 139.6, 164.8, 165.0, 165.1; IR (KBr):
3050, 3026, 2993, 2923, 1641, 1632, 1492, 1449, 1411, 1281, 1245, 969,
746, 695 cm21; MS (m/z): 527.42 (Mþ). Anal. calcd. for C34H32N2O4: C,
81.79; H, 6.86; N, 5.30. Found: C, 81.77; H, 6.59; N, 4.93.

2870
L. Ai et al.
General Procedure for Preparation of Chiral Vicinal
(S,S)-1,2-Diamines 6
For example, the compound 5a (0.46 g, 1.0 mmol) was added to a stirred
refluxing suspension of LiAlH4 (0.19 g, 5.0 mmol) in THF, and the solution
of reaction mixture was refluxed for 4 h with H2O (0.5 mL). Then, 10%
NaOH (2.0 mL) and H2O (1.0 mL) were successively added to the reaction
mixture, and the resulting white precipitate was filtered off. The reaction
solution was extracted with EtOAc (3 ꢀ 15 mL), and the organic phase was
dried over anhydrous Na2SO4 and then concentrated in vacuo. The crude
product was purified by column chromatography on silica gel with
petroleum ether and ethyl acetate (50/1) as eluent to give compound 6a in
.
82% yield. In addition, the solution of BH3 SMe2 (2.0 mmol) in THF was
dropped into a solution of (S,S)-1,2-diacylamides 5d, 5e, and 5f (1.0 mmol)
and then refluxed 20 h. The reaction mixture was quenched with 2.0 N HCl
(20 mL) and then 10% NaOH was added to neutralize residual acid. At last,
the reaction mixture was extracted with EtOAc (3 ꢀ 20 mL). After drying
over anhydrous Na2SO4 overnight, the solvent was evaporated in vacuo.
The crude product was purified by column chromatography on silica gel
with petroleum ether and ethyl acetate (20/1) as eluent to afford diamines
6d, 6e, and 6f in 62–65% yields.
Data
(S,S)-N,N0-bis-Furan-2-ylmethyl N,N0-bis-(1-phenylethyl)-ethane-1,2-dia-
mine (6a): Mp 81–828C; Rf ¼ 0.14 (50:1, petroleum ether/ethyl acetate);
1H NMR (500 MHz, CDCl3); d 1.34 (d, J ¼ 6.72 Hz, 6H, 2 ꢀ CH3), 2.48–
2.57 (m, 4H, CH2CH2), 3.51, 3.67 (2d, J ¼ 14.99 Hz, 4H, 2 ꢀ CH2), 3.75
(q, J ¼ 6.70 Hz, 2H, 2 ꢀ CH), 6.05 (d, J ¼ 2.98 Hz, 2H, 3-furan-H), 6.30–
6.31 (m, 2H, 4-furan-H), 7.23–7.37 (m, 12H, furan-H, aromatic); 13C NMR
(125 MHz, CDCl3): d 17.8, 47.3, 48.4, 59.8, 107.9, 110.0, 126.7, 127.7,
128.1, 141.6, 144.5, 153.7; IR (KBr): 3061, 3025, 2977, 2809, 1500, 1453,
1365, 1331, 1144, 1105, 1011, 917, 778, 733, 703 cm21; MS (m/z): 429.01
(Mþ). Anal. calcd. for C28H32N2O2: C, 78.47; H, 7.53; N, 6.54. Found: C,
78.24; H, 7.54; N, 6.44.
(S,S)-N,N0-bis-(1-Phenylethyl)N,N0-bis-thiophen-2-ylmethylethane-1,2-
diamine (6b): Mp 74–758C; Rf ¼ 0.29 (50:1, petroleum ether/ethyl acetate);
1H NMR (500 MHz, CDCl3): d 1.32 (d, J ¼ 6.77 Hz, 6H, 2 ꢀ CH3), 2.51–
2.66 (m, 4H, CH2CH2), 3.64, 3.79 (2d, J ¼ 14.62 Hz, 4H, 2 ꢀ CH2), 3.84
(q, J ¼ 6.73 Hz, 2H, 2 ꢀ CH), 6.80 (d, J ¼ 2.70 Hz, 2H, thiophen-H), 6.91
(m, 2H, thiophen-H), 7.20–7.35 (m, 12H, thiophen-H, aromatic); 13C NMR
(125 MHz, CDCl3): d 16.1, 48.4, 49.9, 58.5, 124.4, 124.9, 126.2, 126.8,
127.7, 128.0, 143.7,145.0; IR (KBr): 3079, 3028, 2974, 2812, 1491, 1453,

Facile Synthesis with C2-Symmetry
2871
1366, 1328, 1284, 1207, 1165, 1098, 1029, 977, 898, 833, 778, 746,
700 cm21; MS (m/z): 460.97 (Mþ). Anal. calcd. for C28H32N2S2: C, 73.00;
H, 7.00; N, 6.08. Found: C, 73.11; H, 7.35; N, 6.18.
(S,S)-N,N0-Dibenzyl N,N0-bis-(1-phenylethyl)-ethane-1,2-diamine (6c):
Rf ¼ 0.20 (100:1, petroleum ether/ethyl acetate); 1H NMR (500 MHz,
CDCl3): d 1.32 (d, J ¼ 6.54 Hz, 6H, 2 ꢀ CH3), 2.44–2.64 (m, 4H,
CH2CH2), 3.41, 3.56 (2d, J ¼ 13.88 Hz, 4H, 2 ꢀ CH2), 3.78
(q, J ¼ 6.45 Hz, 2H, 2 ꢀ CH), 7.25–7.34 (m, 20H, aromatic); 13C NMR
(125 MHz, CDCl3): d 15.7, 48.3, 55.2, 58.5, 126.6, 127.8, 128.0, 128.1,
128.8, 140.8, 143.8; IR (KBr): 3084, 3061, 3026, 2970, 2932, 2824, 1601,
1493, 1452, 1372, 1028, 745, 698 cm21; MS (m/z): 447.45 (Mþ). Anal.
calcd. for C32H36N2: C, 85.67; H, 8.09; N, 6.24. Found: C, 85.70; H, 7.67;
N, 6.14.
(S,S)-N,N0-bis-(2-Nitro-benzyl)N,N0-bis-(1-phenylethyl)-ethane-1,2-diamine
1
(6d): Mp 113–1148C; Rf ¼ 0.27 (15:1, petroleum ether/ethyl acetate); H
NMR (500 MHz, CDCl3): d 1.24 (d, J ¼ 6.81 Hz, 6H, 2 ꢀ CH3), 2.20–2.35
(m, 4H, CH2CH2), 3.69 (q, J ¼ 6.78 Hz, 2H, 2 ꢀ CH), 3.70, 3.81 (2d,
J ¼ 15.75 Hz, 4H, 2 ꢀ CH2), 7.16–7.45 (m, 14H, aromatic), 7.57
(d, J ¼ 7.60 Hz, 2H, aromatic), 7.78 (d, J ¼ 7.89 Hz, 2H, aromatic); 13C
NMR (125 MHz, CDCl3): d 15.7, 49.4, 53.0, 60.0, 124.2, 126.9, 127.5,
127.6, 128.0, 130.7, 132.4, 136.1, 142.8, 149.6; IR (KBr): 2974, 2937,
2837, 1526, 1493, 1452, 1364, 1205, 1150, 1103, 779, 741, 728, 696 cm21
;
MS (m/z): 269.17 (100). Anal. calcd. for C32H34N4O4: C, 71.35; H, 6.36;
N, 10.40. Found: C, 71.48; H, 6.26; N, 10.54.
(S,S)-N,N0-bis-(3-Nitro-benzyl)N,N0-bis-(1-phenylethyl)-ethane-1,2-diamine
1
(6e): Rf ¼ 0.21 (15:1, petroleum ether/ethyl acetate); H NMR (500 MHz,
CDCl3):
d
1.33 (d, J ¼ 6.79 Hz, 6H, 2 ꢀ CH3), 2.41–2.63 (m,
4H, CH2CH2), 3.47, 3.59 (2d, J ¼ 14.49 Hz, 4H, 2 ꢀ CH2), 3.77
(q, J ¼ 6.73 Hz, 2H, 2 ꢀ CH), 7.24–7.32 (10H, m, aromatic), 7.38–7.41
(t, J ¼ 7.90 Hz, 2H, aromatic), 7.53 (d, J ¼ 7.60 Hz, 2H, aromatic), 8.05
(d, J ¼ 8.11 Hz, 2H, aromatic), 8.12 (s, 2H, aromatic); 13C NMR
(125 MHz, CDCl3): d 15.6, 49.1, 54.6, 59.3, 121.9, 123.1, 127.0, 127.6,
128.2, 128.9, 134.4, 143.0, 143.2, 148.2; IR (KBr): 3062, 3028, 2968, 2929,
2838, 1529, 1492, 1451, 1349, 1202, 1087, 815, 731, 701 cm21; HRMS:
calcd. for C32H34N4O4: Mþ 538.2562; Found: 538.2580.
(S,S)-N,N0-bis-(4-Nitro-benzyl)N,N0-bis-(1-phenylethyl)-ethane-1,2-diamine
1
(6f): Rf ¼ 0.15 (15:1, petroleum ether/ethyl acetate); H NMR (500 MHz,
CDCl3): d 1.31 (d, J ¼ 6.79 Hz, 6H, 2 ꢀ CH3), 2.37–2.59 (m, 4H,
CH2CH2), 3.48, 3.59 (2d, J ¼ 14.87 Hz, 4H, 2 ꢀ CH2), 3.74
(q, J ¼ 6.66 Hz, 2H, 2 ꢀ CH), 7.24–7.37 (m, 10H, aromatic), 7.39 (d,
J ¼ 8.43 Hz, 4H, aromatic), 8.11 (d, J ¼ 8.51 Hz, 4H, aromatic); 13C NMR

2872
L. Ai et al.
(125 MHz, CDCl3): d 15.7, 49.3, 54.9, 59.4, 123.4, 127.1, 127.6, 128.2, 128.9,
143.0, 147.0, 148.9; IR (KBr): 3059, 3028, 2968, 2928, 2848, 1599, 1518,
1492, 1452, 1345, 1109, 1015, 857, 738, 701 cm21; MS (m/z): 269.11
(100). Anal. calcd. for C32H34N4O4: C, 71.35; H, 6.36; N, 10.40. Found: C,
71.39; H, 6.49; N, 10.43.
(S,S)-N,N0-bis-(2-Chloro-benzyl)N,N0-bis-(1-phenylethyl)-ethane-1,2-diamine
1
(6g): Rf ¼ 0.42 (100:1, petroleum ether/ethyl acetate); H NMR (500 MHz,
CDCl3): d 1.32 (m, J ¼ 6.78 Hz, 6H, 2 ꢀ CH3), 2.42–2.62 (m, 4H,
CH2CH2), 3.55, 3.69 (2d, J ¼ 15.23 Hz, 4H, 2 ꢀ CH2), 3.78
(q, J ¼ 6.66 Hz, 2H, 2 ꢀ CH), 7.14–7.53 (m, 18H, aromatic); 13C NMR
(125 MHz, CDCl3): d 15.5, 49.2, 52.3, 59.2, 126.5, 126.6, 127.6,
127.7, 128.0, 129.2, 130.3, 133.6, 138.2, 143.5; IR (KBr): 3061, 3027,
2971, 2933, 2828, 1738, 1493, 1443, 1373, 1241, 1202, 1143, 1119,
1048, 1036, 752, 700 cm21; MS (m/z): 517.32 (Mþ). Anal. calcd. for
.
C32H34 Cl2N2 2HCl: C, 65.09; H, 6.15; N, 4.74. Found: C, 64.62; H, 6.53;
N, 4.35.
(S,S)-N,N0-bis-(3-Chloro-benzyl)N,N0-bis-(1-phenylethyl)-ethane-1,2-dia-
mine (6h): Rf ¼ 0.26 (100:1, petroleum ether/ethyl acetate); 1H NMR
(500 MHz, CDCl3): d 1.33 (d, J ¼ 6.74 Hz, 6H, 2 ꢀ CH3), 2.42–2.62
(m, 4H, CH2CH2), 3.37, 3.53 (2d, J ¼ 14.18 Hz, 4H, 2 ꢀ CH2), 3.77
(q, J ¼ 6.67 Hz, 2H, 2 ꢀ CH), 7.14–7.36 (m, 18H, aromatic); 13C NMR
(125 MHz, CDCl3): d 15.8, 48.6, 54.8, 58.9, 126.6, 126.8, 126.9, 127.7,
128.1, 128.5, 129.4, 134.0, 143.1, 143.3; IR (KBr): 3060, 3027, 2970, 2825,
1597, 1574, 1492, 1474, 1451, 1428, 1373, 1201, 1116, 1075, 776, 734,
700 cm21; MS (m/z): 517.35 (Mþ). Anal. calcd. for C32H34 Cl2N2 2HCl:
.
C, 65.09; H, 6.15; N, 4.74. Found: C, 64.79; H, 6.32; N, 4.53.
(S,S)-N,N0-bis-(4-Chloro-benzyl)N,N0-bis-(1-phenyl-ethyl)-ethane-1,2-dia-
mine (6i): Mp 82–838C; Rf ¼ 0.20 (100:1, petroleum ether/ethyl acetate); 1H
NMR (500 MHz, CDCl3) d 1.38 (d, J ¼ 6.80 Hz, 6H, 2 ꢀ CH3), 2.45–2.65
(m, 4H, CH2CH2), 3.42, 3.55 (2d, J ¼ 14.02 Hz, 4H, 2 ꢀ CH2), 3.83
(q, J ¼ 6.75 Hz, 2H, 2 ꢀ CH), 7.15–7.49 (m, 18H, aromatic); 13C NMR
(125 MHz, CDCl3): d 15.6, 48.6, 54.6, 58.9, 126.8, 127.7, 127.9, 128.1,
128.2, 129.8, 132.2, 139.3, 143.5; IR (KBr): 3061, 3027, 2972, 2931,
2823, 1594, 1490, 1451, 1405, 1368, 1302, 1248, 1150, 1101, 1085,
1013, 926, 850, 806, 702 cm21; MS (m/z): 516.98 (Mþ). Anal. calcd.
for C32H34Cl2N2: C, 74.26; H, 6.62; N, 5.41. Found: C, 74.11; H, 6.70; N,
5.15.
(S,S)-N,N0-bis-(2-Methoxy-benzyl)N,N0-bis-(1-phenylethyl)-ethane-1,2-dia-
mine (6j): Rf ¼ 0.22 (15:1, petroleum ether/ethyl acetate); 1H NMR
(500 MHz, CDCl3): d 1.34 (d, J ¼ 6.78 Hz, 6H, 2 ꢀ CH3), 2.54–2.68
(m, 4H, CH2CH2), 3.49, 3.66 (2d, J ¼ 15.12 Hz, 4H, 2 ꢀ CH2), 3.78 (s, 6H,

Facile Synthesis with C2-Symmetry
2873
2 ꢀ OCH3), 3.83 (q, J ¼ 6.73 Hz, 2H, 2 ꢀ CH), 6.82 (d, J ¼ 8.13 Hz, 1H,
aromatic), 6.91–7.33 (m, 16H, aromatic), 7.48 (J ¼ 7.34 Hz, 1H, aromatic);
13C NMR (125 MHz, CDCl3): d 15.7, 48.5, 49.0, 55.2, 58.8, 110.0, 120.4,
126.4, 127.2, 127.8, 127.9, 129.1, 129.6, 144.2, 157.4; IR (KBr): 3060,
3027, 2967, 2834, 1600, 1587, 1491, 1463, 1438, 1373, 1286, 1239,
1104, 1049, 1031, 754, 701 cm21; MS (m/z): 509.41 (Mþ). Anal. calcd.
for C32H40N2O2: C, 80.28; H, 7.93; N, 5.51. Found: C, 79.79; H, 8.20;
N, 5.31.
(S,S)-N,N0-bis-(3-Methoxy-benzyl)N,N0-bis-(1-phenylethyl)-ethane-1,2-dia-
mine (6k): Rf ¼ 0.36 (15:1, petroleum ether/ethyl acetate); 1H NMR
(500 MHz, CDCl3): d 1.30 (d, J ¼ 6.79 Hz, 6H, 2 ꢀ CH3), 2.42–2.63
(m, 4H, CH2CH2), 3.38, 3.53 (2d, J ¼ 14.08 Hz, 4H, 2 ꢀ CH2), 3.76
(q, J ¼ 6.69 Hz, 2H, 2 ꢀ CH), 3.79 (s, 6H, 2 ꢀ OCH3), 6.76–7.29
(m, 18H, aromatic); 13C NMR (125 MHz, CDCl3): d 15.8, 48.6, 55.1,
55.2, 58.6, 112.1, 113.9, 120.8, 126.6, 127.8, 128.0, 129.0, 142.7, 143.6,
159.6; IR (KBr): 3058, 3027, 2967, 2833, 1600, 1585, 1489, 1453, 1372,
1263, 1151, 1117, 1049, 778, 734, 699 cm21; MS (m/z): 509.43 (Mþ).
Anal. calcd. for C34H40N2O2: C, 80.28; H, 7.93; N, 5.51. Found: C,
80.37; H, 8.15; N, 5.22.
(S,S)-N,N0-bis-(4-Methoxy-benzyl)N,N0-bis-(1-phenylethyl)-ethane-1,2-dia-
mine (6l): Rf ¼ 0.40 (10:1, petroleum ether/ethyl acetate); 1H NMR
(500 MHz, CDCl3): d 1.25 (d, J ¼ 7.11 Hz, 6H, 2 ꢀ CH3), 2.39–2.59
(m, 4H, CH2CH2), 3.32, 3.46 (2d, J ¼ 13.66 Hz, 4H, 2 ꢀ CH2), 3.75
(q, J ¼ 6.81 Hz, 2H, 2 ꢀ CH), 3.82 (s, 6H, 2 ꢀ OCH3), 6.82
(d, J ¼ 8.56 Hz, 4H, aromatic), 7.16 (d, J ¼ 8.51 Hz, 4H, aromatic),
7.23–7.31 (m, 10H, aromatic); 13C NMR (125 MHz, CDCl3): d 15.6,
48.1, 54.4, 55.2, 58.4, 113.4, 126.6, 127.8, 128.0, 129.7, 132.8, 143.9,
158.4; IR (KBr): 3060, 3027, 2967, 2832, 1611, 1511, 1452, 1372, 1301,
1248, 1170, 1104, 1037, 734, 701 cm21; MS (m/z): 507.35 (Mþ). Anal.
calcd. for C34H40N2O2: C, 80.28; H, 7.93; N, 5.51. Found: C, 80.55; H,
8.03; N, 5.26.
(S,S)-N,N0-bis-(3-Phenyl-allyl)N,N0-bis-(1-phenylethyl)-ethane-1,2-diamine
1
(6m): Rf ¼ 0.28 (10:1, petroleum ether/ethyl acetate); H NMR (500 MHz,
CDCl3): d 1.34 (d, J ¼ 6.67 Hz, 6H, 2 ꢀ CH3), 2.57–2.66 (m, 4H,
CH2CH2), 3.13–3.18 (m, 4H, 2 ꢀ CH2), 3.85 (q, J ¼ 6.68 Hz, 2H, 2 ꢀ CH),
6.18–6.24 (m, 2H, 2 ꢀ CH55), 6.43 (d, J ¼ 15.87 Hz, 2H, 2 ꢀ CH55),
7.22–7.34 (m, 20H, aromatic); 13C NMR (125 MHz, CDCl3): d 17.1,
48.7, 53.8, 59.6, 126.3, 126.7, 127.2, 127.7, 128.0, 128.4, 128.7,
131.7, 137.3, 144.2; IR (KBr): 3059, 3025, 2968, 1600, 1493, 1449, 1370,
1118, 1075, 1030, 966, 742, 699 cm21; MS (m/z): 499.19 (Mþ). Anal.
calcd. for C34H36N2: C, 86.35; H, 8.05; N, 5.59. Found: C, 85.90; H, 8.35;
N, 5.61.

2874
L. Ai et al.
ACKNOWLEDGMENT
This work was supported by the National Natural Science Foundation of
China (No. 20172008).
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