Copper(I) catalysis: Synthesis of N,N′-diarylated and N-aryl,N′-formylated chiral C2-symmetric diamines

Article abstract of DOI:10.1016/j.jorganchem.2009.08.002

Chiral N,N′-diaryl C₂-symmetric diamines and N-aryl,N′-formyl-trans-(1R,2R)-diaminocyclohexane are readily accessed by copper catalyzed N,N′-diarylation and N-aryl,N′-formylation of trans-(1R,2R)-diaminocyclohexane with aryl bromides. N,N′-diar

Full text of DOI:10.1016/j.jorganchem.2009.08.002

Journal of Organometallic Chemistry 694 (2009) 3859–3863
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Copper(I) catalysis: Synthesis of N,N0-diarylated and N-aryl,N0-formylated chiral
C2-symmetric diamines
*
Laxhmaiah Alakonda, Mariappan Periasamy
School of Chemistry, University of Hyderabad, Central University P.O., Hyderabad 500 046, India
a r t i c l e i n f o
a b s t r a c t
Chiral N,N0-diaryl C2-symmetric diamines and N-aryl,N0-formyl-trans-(1R,2R)-diaminocyclohexane are
readily accessed by copper catalyzed N,N0-diarylation and N-aryl,N0-formylation of trans-(1R,2R)-diami-
nocyclohexane with aryl bromides. N,N0-diarylation using (R)-1,10-binaphthyl-2,20-diamine and iodoben-
zene gave the corresponding (R)-N,N0-diphenyl-1,10-binaphthyl-2,20-diamine derivative in 83% yield.
Ó 2009 Elsevier B.V. All rights reserved.
Article history:
Received 28 May 2009
Received in revised form 18 July 2009
Accepted 4 August 2009
Available online 8 August 2009
Keywords:
Copper(I) catalysis
Bi-2-naphthol
Chiral cyclohexyl diamine
1,10-Binaphthyl-2,20-diamine
N-arylation
N-formylation
1. Introduction
2. Results and discussion
Ligands derived from certain C2-symmetric enantiopure dia-
mines have been widely employed in asymmetric transformations
including epoxidation [1], allylic substitution [2] and hydrogena-
tion reactions [3]. Especially, the chiral trans-1,2-diaminocyclohex-
ane and its derivatives were widely used in asymmetric synthesis
as chiral reagents, scaffolds and as ligands in many organic trans-
formations [4]. It was observed in this laboratory that N,N0-diphe-
nylation of trans-(1R,2R)-diaminocyclohexane with bromobenzene
using sodium metal in THF gave the diamine in poor yield (10%)
besides biphenyl. Therefore, we were looking for a convenient
alternative method for N-arylation of diamines [5]. Though car-
bon–nitrogen bond forming reactions employing primary amines
and aryl halides as coupling partners using both palladium [6]
and copper [7] catalyst systems have been reported, a mild, eco-
nomic and efficient catalytic system is desirable for N,N0-diaryla-
tion of chiral C2-symmetric diamines. Herein, we report
convenient methods for copper(I) catalyzed N,N0-diarylation of chi-
ral C2-symmetric diamines 4 and 7 to obtain the corresponding
We have screened the ligands 1, 2 and 3 for the N,N0-diarylation
of trans-(1R,2R)-diaminocyclohexane under copper(I) catalysis (see
Fig. 1). We have observed that the N,N0-diarylation of
trans-(1R,2R)-diaminocyclohexane gave the corresponding N,N0-di-
phenyl-trans-(1R,2R)-diaminocyclohexane (6a) (Scheme
1 and
Table 1).
The catalytic systems using rac-BINOL 3 gave better results in
the diarylation (Table 1). Accordingly we have examined the diary-
lation of trans-(1R,2R)-diaminocyclohexane (4) with various aryl
bromides using this reagent (Table 2, entries 1–4). The % ee of
starting trans-(1R,2R)-diaminocyclohexane is >98% ee. Since the
reaction does not involve changes in the asymmetric centers, the
ee of the product should be the same (Table 2, entries 1–4). Indeed,
the % ee of the product was found to be >98% in the case of product
6a by HPLC analysis. The yields are better in reactions using aryl
bromides containing electron donating substituents (Table
entries 2 and 3).
2
The transformation was also examined using the (R)-1,
10-binaphthyl-2,20-diamine (7). The corresponding (R)-N,N0-diphe-
nyl-1,10-binaphthyl-2,20-diamine (8) was obtained in 19–83% yield
(Scheme 2, Table 2). We have observed that partial racemization of
the product 8 takes place under the reaction conditions and the
(R)-N,N0-diphenyl-1,10-binaphthyl-2,20-diamine (8) was obtained
in 13% to 91% ee indicating partial racemization during the N-ary-
lation (Table 2, entries 5–8). It is well-known that optically active
isomers containing 1,10-binaphthyl moiety interconvert at high
N,N0-dirayl-1,2-diaminocyclohexane
6a–d,
(R)-N,N0-diphenyl-
1,10-binaphthyl-2,20-diamine (8) and N-aryl,N0-formylation of
trans-(1R,2R)-diaminocyclohexane (4) to obtain N-formyl,N0-phe-
nyl-trans-(1R,2R)-diaminocyclohexane (9).
* Corresponding author. Tel.: +91 40 23134814; fax: +91 40 23012460.
E-mail address: mpsc@uohyd.ernet.in (M. Periasamy).
0022-328X/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2009.08.002

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L. Alakonda, M. Periasamy / Journal of Organometallic Chemistry 694 (2009) 3859–3863
Table 1
N,N0-diarylation of trans-(1R,2R)-diaminocyclohexane 4 with various catalysts.a
N
N
OH
OH
Entry Catalyst
Halo
benzenes
Ligand Base
Time
(h)
Yield
(%)b
R
R
1
2
3
4
5
6
7
8
9
CuBr
CuBr
CuBr
CuBr
CuBr
CuBr
CuI
CuBr
CuBr/
Fe2O3
CuBr/
Fe2O3
CuBr/ZnO
CuO/NiBr
5a
5a
5a
5a
5a
5b
5a
5b
5b
1
1
2
3
3
3
3
–
3
K2CO3 48
K3PO4 48
10
17
34
50
78
94
56
5c
1, R = H, N,N'-dibenzylidineethane-1,2-diamine
3, ( )-Bi-2-naphthol (rac - BINOL)
K3PO4 48
K2CO3 48
K3PO4 36
K3PO4 36
K3PO4 48
K3PO4 48
K3PO4 36
2, R = OMe, N,N'-bis (4-methoxybenzylidine)
ethane-1,2-diamine
Fig. 1. Ligands examined for N-arylation of chiral C2-symmetric diamines.
84
Ph
X
NH2
NH2
Catalyst (10 mol %)/Ligand (20 mol %)
Base, DMF, 120 °C, 36-48 h
NH
10
5a
3
K3PO4 36
76
+
11
12
5b
5b
3
3
K3PO4 36
K3PO4 48
73
15
NH
Ph
R
6a
4
a
y : 10 -94 %
5a, X = Br, R = H
5b, X = I, R = H
All the reactions were carried out with each metal catalyst (10 mol%), ligand
(20 mol%), trans-(1R,2R)-diaminocyclohexane 4 (1 mmol), halobenzene (4 mmol)
and DMF (5 mL) at 120 °C.
Scheme 1. Coupling of trans-(1R,2R)-diaminocyclohexane (4) and halobenzene in
the presence of copper(I) catalyst.
Product was identified by 1H NMR, 13C NMR and mass spectral data.
b
c
Reaction was carried out without employing any ligand.
Table 2
Synthesis of N,N0-diaryl-trans-(1R,2R)-diaminocyclohexane 6a–d and (R)-N,N0-diphenyl-1,10-binaphthyl-2,20-diamine (8).a
Entry
1
Aryl halide
Product
Time (h)
36
Yield (%)b
78
ee (%)e
>98
5a
NH HN
6a
2
5c
5d
5e
5b
36
36
36
36
61
71
49
83
>98
>98
>98
13d
H3C
MeO
O2N
NH HN
CH3
OMe
NO2
6b
3
NH HN
6c
4
NH HN
6d
5c
N
H
H
N
8
6
5b
5b
5b
8
8
8
24
12
48
36
19
39
59
91
58
7
8f
a
Unless noted otherwise, all the reactions were carried out with copper bromide (10 mol%), rac-BINOL 3 (20 mol%), trans-(1R,2R)-diaminocyclohexane 4 (1 mmol), aryl
bromide (4 mmol), K3PO4 (3 mmol), DMF (5 mL) at 120 °C.
b
All the products were identified by 1H NMR, 13C NMR and mass spectral data.
c
(R)-1,10-binaphthyl-2,20-diamine 7 was used as substrate diamine.
d
Bis-phenylation of rac-BINOL 3 was also observed (up to 20%).
Since the reaction does not involve changes in the asymmetric centers the ee of the product should be the same and was confirmed by using chiral HPLC for product 6a: on
e
Daicel Chiralcel OD-H (elution hexane:isopropanol, 95/5, flow rate:1 mL/min UV detection at 254 nm) showed >98% ee (tS = 10.5 min) and ee of product 8 was determined by
using chiral HPLC on Daicel Chiral Pak AD-H (elution hexane–ethanol 19:1, flow rate:1 mL/min UV detection at 256 nm) showed 13–91% ee (tS = 4.3 min, tR = 5.8 min).
f
Reaction was carried out at 100 °C.

L. Alakonda, M. Periasamy / Journal of Organometallic Chemistry 694 (2009) 3859–3863
3861
Ar
Ar
Br
NH
NH
NH2
NH2
CuBr (10 mol %)/rac-BINOL(20 mol %)
+
*
*
*
+
K3PO4, DMF, 120 °C, 36 h
NH
CHO
9
NH
Ar
6a-d, 8
R
4, 7
5a, R = H
5c, R = CH3
5d, R = OCH3
5e, R = NO2
y : 36-78 %
trace (< 5 % )
(
NH2
NH2
Ar =
NH2
NH2
R
NH2
=
*
NH2
,
7
4
Scheme 2. Synthesis of N,N0-diaryl chiral C2-symmetric diamines.
Ph
Ph
Br
NH2
NH
NH
CuBr (10 mol %)/ligand 1 or 3 (20 mol %)
+
+
tBuOK, DMF, 130 °C, 48 h
NH2
NH
CHO
NH
Ph
9
5a
6a
y : < 10 %
4
y : 78-93 %
Scheme 3. Synthesis of N-formyl,N0-phenyl- trans-(1R,2R)-diaminocyclohexane 9.
may be of interest to note that formylation of certain amines has
reported in reactions with CH3ONa and DMF [9].
Table 3
Synthesis of N-formyl,N0-phenyl-trans-(1R,2R)-diaminocyclohexane (9).a
Interestingly, the compound 9 was isolated in 76% yield, even in
the absence of ligand (Table 3, entry 3). We thought that the ini-
tially formed N-formyl,N0-phenyl-trans-(1R,2R)-diaminocyclohex-
ane (9) itself is acting as ligand to give product 9. In order to
examine this possibility, we have used the compound 9 in the
N,N0-diphenylation of trans-(1R,2R)-diaminocyclohexane (4). In
this run, the corresponding N,N0-diphenyl derivative 6a was ob-
tained in 40% yield. The structure of the N-formyl,N0-phenyl-
trans-(1R,2R)-diaminocyclohexane (9) was further confirmed by
X-ray crystal structure analysis. The ORTEP diagram is shown in
Fig. 2.
Entry
Catalyst
Ligand
Base
Yield (%)b
1
CuBr
CuBr
CuBr
CuBr
1
3
–
3
tBuOK
tBuOK
tBuOK
K3PO4
78
93
76
Trace
2
3c
4
a
Unless noted otherwise, all the reactions were carried out with CuBr (10 mol%),
ligand 1 or 3 (20 mol%), trans-(1R,2R)-diaminocyclohexane 4 (1 mmol), bromo-
benzene 5a (1.2 mmol), tBuOK (2.5 mmol) and DMF (5 mL) at 130 °C for 48 h.
Product 9 was identified by 1H NMR, 13C NMR and mass spectral data, X-ray
b
crystal structure analysis.
c
Reaction was carried out without employing any ligand.
The N,N0-diarylation and N-aryl,N0-formylation transformations
may be rationalized by the tentative mechanisms outlined in
Scheme 4 considering reports on copper(I) catalyzed N-arylations
[10].
Initially, the copper(I) halide 10 coordinates with bidentate li-
gand 3 (1 or 2) to form the metal–ligand complex 11 (Scheme 4).
Subsequent, oxidative addition of aryl halide 5 would give the cop-
per(III) complex 12. Then, the deprotonated amine 4 or 7 would re-
act with the diamine to form the complex 13, which on reductive
elimination would give the product 14 and the copper(I) that could
participate in the catalytic cycle again. The product 14 could react
Fig. 2. ORTEP diagram of N-formyl,N0-phenyl-trans-(1R,2R)-diaminocyclohexane
(9) (thermal ellipsoids are drawn at 35% probability and all the hydrogen atoms
were unlabled for clarity).
t
with DMF in the presence of BuOK to yield N0-formylated com-
pound 9 through the intermediate 15.
3. Conclusion
temperatures in long time reactions [8]. Accordingly, this partial
racemization in the high temperature reactions is not entirely
unexpected.
In summary, we have developed inexpensive and convenient
methods for N,N0-diarylation and N-formylation of chiral C2-sym-
metric diamines. The products are expected to be useful ligands
for developing new catalyst systems for application in asymmetric
transformations. Especially, the unsymmetrical nature of the N-
formyl,N0-phenyl-trans-(1R,2R)-diaminocyclohexane should be
helpful in designing of new unsymmetrical diamine ligands. The
N-aryl amine derivatives are also useful in several material science
applications [11]. Therefore, the methods for N-arylation and
In all experiments with trans-(1R,2R)-diaminocyclohexane, the
N-aryl,N0-formyl-trans-(1R,2R)-diaminocyclohexane was obtained
in trace amount (<5%). Interestingly, when tBuOK was used in com-
bination with the CuBr/rac-BINOL system, the mono phenyl and
mono formyl product 9 was obtained in good to excellent yields
(Scheme 3 and Table 3, entries 1 and 2). This transformation may
t
be attributed to increased solubility and basicity of the BuOK. It

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L. Alakonda, M. Periasamy / Journal of Organometallic Chemistry 694 (2009) 3859–3863
Cu(I)X (X = Br or I)
10
L
3 (1 or 2)
Ph
Ar-X
Ar
5
L
O
NH
tBuOK
NH
L
O
N
+
H
Cu(I)X
N
N
H
NHR
L
R = H
14
11
Ar = Ph
15
Ar
Ar
L
L
(CH3)2NH
L
L
13
Ar
12
Cu(III)X
X
Cu(III)X
NH
NH
Ph
NH
Ar
NH
RHN
NH2
NH
CHO
9
6, R =Ar
8, Ar = R = Ph
+ K3PO4 (K2CO3 or tBuOK)
+
K2HPO4
KX
NHR
4, 7
X = Br or I
R = H or Ar
Scheme 4. Copper(I) catalyzed N,N0-diarylation and N-aryl,N0-formylation of diamines.
N-aryl,N0-formylation of diamines described here have consider-
able potential for further synthetic exploitations.
(100 MHz, CDCl3): d = 24.6, 32.6, 57.3, 113.5, 117.6, 129.3, 147.8;
LCMS (m/z): 267 (M+1); HPLC analysis: Daicel Chiralcel OD-H (elu-
tion hexane–isopropanol, 95:5, flow rate: 1 mL/min UV detection
at 254 nm) showed the product with >98% ee (tR = 10.5 min, for
(1R,2R)) [13b].
4. Experimental
Infrared spectra were recorded on JASCO FT-IR spectrophotom-
eter Model 5300. 1H NMR and 13C NMR spectra were recorded on
Bruker AV-400 spectrometers with chloroform-d as a solvent and
TMS as the reference (d = 0 ppm). Coupling constants J are in Hz.
Elemental analyses were carried out on a Flash EA 1112 series ana-
lyzer. Optical rotations were measured in an AUTOPOL-IV auto-
matic polarimeter (readability 0.001). HPLC analysis performed
on SCL-10ATVP Shimadzu instrument. Chromatography was car-
ried out using Acme0s silica gel (100–200 mesh and 230–400
mesh). Solvents were dried using the standard procedures. The
commercial reagents were used without further purification. The
commercial cis/trans mixture of 1,2-diaminocyclohexane was re-
solved to obtain the trans-(1R,2R)-diaminocyclohexane in >98%
ee following a reported procedure [12].
4.1.2. Synthesis of trans-(1R,2R)-N,N0-di-p-tolylcyclohexane-1,2-
diamine (6b)
Synthesized following the above general procedure: Yield:
25
0.180 g, 61% as gummy; aD ¼ þ85:7ꢁ (c = 0.58, benzene), lit.
[13a] aD ¼ þ101:5ꢁ (c = 0.98, benzene); FTIR (neat) mmax (cmꢂ1):
25
3385, 3018, 2928, 1616, 1516, 1300, 808; 1H NMR (400 MHz,
CDCl3): d = 1.19–1.21 (m, 2H), 1.37–1.40 (m, 2H), 1.75–1.77 (m,
2H), 2.22–2.24 (d, 6H), 2.31–2.34 (m, 2H), 3.13–3.15 (m, 2H),
3.75 (brs, 2H, NH), 6.53–6.56 (m, 4H), 6.96–7.00 (m, 4H); 13C
NMR (100 MHz, CDCl3): d = 20.4, 24.6, 32.6, 57.68, 113.9, 126.9,
129.8, 145.5; LCMS (m/z): 295 (Mꢂ1).
4.1.3. Synthesis of trans-(1R,2R)-N,N0-bis-(4-methoxyphenyl)-
cyclohexane-1,2-diamine (6c)
Synthesized following the above general procedure: Yield:
4.1. General procedure for the synthesis of N-aryl chiral diamines 6a–d
and 8
25
0.231 g, 71% as gummy; aD ¼ þ29:2ꢁ (c = 0.24, CHCl3); FTIR
(neat) mmax (cmꢂ1): 3354, 3030, 2993, 1616, 1510, 1037, 819; 1H
NMR (400 MHz, CDCl3): d = 1.4 (m, 2H), 1.76–1.78 (m, 2H), 2.30–
2.33 (m, 2H), 3.07–3.09 (m, 2H), 3.68 (brs, 2H, NH), 3.75–3.76 (d,
6H), 6.61–6.64 (m, 4H), 6.78–6.81 (m, 4H); 13C NMR (100 MHz,
CDCl3): d = 24.7, 32.6, 55.8, 58.5, 114.9, 115.5.3, 141.9, 152.4; LCMS
(m/z): 327 (M+1).
In a 25 mL two necked flask equipped with air condenser pro-
tected by a mercury trap, CuBr (10 mol%, 14.3 mg), rac-BINOL
(20 mol%, 57.2 mg), K3PO4 (3 mmol, 636 mg) and DMF (5 mL) were
placed under nitrogen. The contents were stirred for 20–30 min at
25 °C. To this, chiral diamine (1 mmol, 114.2 mg) and aryl halide
(4 mmol, 628 mg) were added and stirring was continued for
36 h at 120 °C. The reaction mixture was brought to 25 °C, diluted
with 10 mL of ethyl acetate and 5 mL of water and stirred for
10 min at 25 °C. The organic layer was separated and the aqueous
layer was extracted with ethyl acetate (3 ꢀ 10 mL). The combined
organic extract was washed with water and brine and then dried
over anhydrous Na2SO4. The solvent was evaporated and the resi-
due was purified by column chromatography (silica gel 100–200
mesh, hexanes/ethyl acetate) to yield the desired product.
4.1.4. Synthesis of trans-(1R,2R)-N,N0-bis-(4-nitrophenyl)-
cyclohexane-1,2-diamine (6d)
Synthesized following the above general procedure: Yield:
0.174 g; 49% as yellow solid; m.p: 200–202 °C; lit. [14] m.p: 204–
25
25
206 °C; aD ¼ þ904:5ꢁ (c = 0.34, methanol), lit. [14] aD ¼ þ875ꢁ
(c = 0.192, methanol); FTIR (KBr) mmax (cmꢂ1): 3356, 3084, 2930,
1595, 1527, 1298, 1111, 831; 1H NMR (400 MHz, DMSO-d6):
d = 1.26–1.33 (m, 2H), 1.36–1.45 (m, 2H), 1.84 (m, 2H), 2.25–2.28
(m, 2H), 3.42 (m, 2H), 5.63 (brs, 2H, NH), 6.53–6.55 (m, 4H),
7.93–7.95 (m, 4H); 13C NMR (100 MHz, CDCl3): d = 24.4, 32.1,
56.3, 111.1, 126.4, 136.9, 153.3; LCMS (m/z): 357 (M+1).
4.1.1. Synthesis of trans-(1R,2R)-N,N0-diphenylcyclohexane-1,2-
diamine (6a)
Synthesized following the above general procedure: Yield:
25
0.207 g, 78% as yellow oil; aD ¼ þ66:3ꢁ (c = 0.58, benzene), lit.
4.1.5. Synthesis of (R)-N,N0-diphenyl-1,10-binaphthyl-2,20-diamine (8)
[13a] aD ¼ þ64:1ꢁ (c = 0.95, benzene); FTIR (neat) mmax (cmꢂ1):
Synthesized following the above general procedure: Yield:
25
3391, 3051, 2930, 1601, 1500; 1H NMR (400 MHz, CDCl3):
d = 1.21–1.24 (m, 2H), 1.32–1.47 (m, 2H), 1.76–1.79 (m, 2H),
2.33–2.36 (m, 2H), 3.17–3.21 (m, 2H), 3.89 (brs, 2H, NH), 6.61–
6.63 (m, 4H), 6.69–6.73 (m, 2H), 7.15–7.19 (m, 4H); 13C NMR
0.362 g, 83% as amorphous solid; aD ¼ þ54:9ꢁ (c = 0.15, THF)
25
for 91% ee, lit. [15] [a]D = +63. 4° (c = 0.4, THF) for 98% ee; FTIR
(KBr) mmax (cmꢂ1): 3395, 3051, 1936, 1732, 1612, 1591, 1494,
810, 738; 1H NMR (400 MHz, CDCl3): d = 5.60 (brs, 2H), 6.81–6.97

L. Alakonda, M. Periasamy / Journal of Organometallic Chemistry 694 (2009) 3859–3863
3863
(m, 6H), 7.12–7.24 (m, 7H), 7.29–7.42 (m, 4H), 7.67–7.89 (m, 5H);
Acknowledgements
13C NMR (100 MHz, CDCl3): d = 116.4, 117.9, 120.0, 122.2, 123.5,
124.5, 127.1, 128.3, 129.1, 129.3, 129.4, 134.0, 140.4, 142.5; LCMS
(m/z): 267 (M+1); 437 (M+1); HPLC on Daicel Chiral Pak AD-H (elu-
tion hexane–ethanol 19:1, flow rate:1 mL/min UV detection at
256 nm) showed 13–91% ee (tS = 4.3 min, tR = 5.8 min) [15].
We are thankful to the CSIR for a research fellowship to LA.
UGC supports under the ‘University with Potential for Excellence
(UPE)’ and Centre for Advance Studies (CAS) and UGC-MHRD
Chemistry Networking Centre program are gratefully acknowl-
edged. We are also thankful to the DST for the 400 MHz NMR spec-
trometer facility under FIST program and National XRD-CCD
facility under IRHPA program in the School of Chemistry, Univer-
sity of Hyderabad and for the award of the JC Bose Fellowship
Grant to MP.
4.2. Representative procedure for the synthesis of N-formyl,N0-phenyl-
trans-(1R,2R)-diaminocyclohexane (9)
In a 25 mL two necked flask equipped with air condenser pro-
tected by a mercury trap, CuBr (10 mol%, 14.3 mg), rac-BINOL
(20 mol%, 57.2 mg), tBuOK (3 mmol, 336 mg) and DMF (5 mL) were
placed under nitrogen. The contents were stirred for 20–30 min at
25 °C. To this, trans-(1R,2R)-diaminocyclohexane (4) (1 mmol,
114.2 mg) and bromobenzene 5a (1.2 mmol, 188.4 mg) were
added and stirring was continued for 48 h at 130 °C. The reaction
mixture was brought to 25 °C, diluted with 10 mL of ethyl acetate
and 5 mL of water and stirred for 10 min at 25 °C. The organic layer
was separated and the aqueous layer was extracted with ethyl ace-
tate (3 ꢀ 10 mL). The combined organic extract was washed with
water and brine and then dried over anhydrous Na2SO4. The sol-
vent was evaporated and the residue was purified by column chro-
matography (silica gel, hexanes/ethyl acetate = 75/25) to yield the
desired product.
Appendix A. Supplementary material
CCDC 728374 contains the supplementary crystallographic data
for this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif. Supplementary data associated with this article
can be found, in the online version, at doi:10.1016/j.jorganchem.
2009.08.002.
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(b) L. Alakonda, M. Periasamy, unpublished results.
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(b) M.S. Driver, J.F. Hartwig, J. Am. Chem. Soc. 118 (1996) 7217;
(c) For a recent review, see:C.G. Frost, P. Mendonca, J. Chem. Soc., Perkin Trans.
1 (1998) 2615;
4.3. Physical and spectral data for compound 9
Yield: 0.203 g, 93% as colorless solid; m.p.: 106–108 °C;
aD ¼ þ39:4ꢁ (c = 0.86, CHCl3); FTIR (KBr) mmax (cmꢂ1): 3400,
25
3333, 3022, 2924, 1635, 1604, 1523, 746, 690; 1H NMR
(400 MHz, CDCl3): d = 1.12–1.27 (m, 2H), 1.30–1.43 (m, 2H),
1.66–1.76 (m, 2H), 2.07–2.10 (m, 1H), 2.24–2.28 (m, 1H), 3.07
(brs, 1H), 3.85–3 (m, 1H), 4.06 (brs, 1H), 5.56 (m, 2H, NH), 6.53–
6.58 (m, 2H), 6.63–6.70 (m, 1H), 7.11–7.25 (m, 2H), 8.09 (s, 1H);
13C NMR (100 MHz, CDCl3): d = 24.5, 24.8, 32.5, 32.7, 51.8, 58.0,
112.6, 117.0, 129.3, 147.5, 161.8; LCMS (m/z): 219 (M+1). Elemen-
tal Anal. Calc. for C13H18N2O: C, 71.53; H, 8.31; N, 12.83. Found: C,
71.46; H, 8.35; N, 12.91%.
(d) S. Wagaw, R.A. Rennels, S.L. Buchwald, J. Am. Chem. Soc. 119 (1997) 8451;
(e) C.G. Frost, P. Mendonça, Tetrahedron: Asymmetr. 10 (1999) 1831;
(f) For N-arylation of 1,2-diamines:N.R. Swamy, Y. Venkateswarlu, Synth.
commun. 33 (2003) 547.
[7] (a) D. Jiang, H. Fu, Y. Jiang, Y. Zhao, J. Org. Chem. 72 (2007) 672;
(b) D. Zhu, R. Wang, J. Mao, L. Xu, F. Wu, B. Wan, J. Mol. Catal. A: Chem. 256
(2006) 256.
[8] Y. Chen, S. Yekta, A.K. Yudin, Chem. Rev. 103 (2003) 3155.
[9] G.R. Pettit, E.G. Thomas, J. Org. Chem. 24 (1959) 895.
[10] (a) S.V. Ley, A.W. Thomas, Angew. Chem., Int. Ed. 42 (2003) 5400;
(b) A. Klapars, X. Huang, S.L. Buchwald, J. Am. Chem. Soc. 124 (2002) 7421.
[11] (a) F. Hussain, M. Hojjati, J. Comp. Mater. 60 (2007) 729;
(b) S. Sinnwell, H. Ritter, Aust. J. Chem. 40 (2006) 1511;
(c) K. Hara, M. Kurashige, S. Ito, A. Shinpo, S. Suga, K. Sayama, H. Arakawa,
Chem. Commun. 2 (2003) 252.
4.4. Crystal data for compound 9
[12] J.F. Larrow, E.N. Jacobsen, Y. Gao, Y. Hong, X. Nie, C.M. Zepp, J. Org. Chem. 59
(1994) 1969.
[13] (a) H. Aoyama, M. Tokunaga, J. Kiyosu, T. Iwasawa, Y. Obora, Y. Tsji, J. Am.
Chem. Soc. 127 (2005) 10474;
Molecular formula: C13H18N2O, Mw = 218.29, orthorhombic,
space group: P2(1)2(1)2(1), a = 5.1335(4) Å, b = 7.7826(6) Å,
(b) K. Arai, S. Lucarini, M.M. Salter, K. Ohta, Y. Yamashita, S. Kobayashi, J. Am.
Chem. Soc. 129 (2007) 8103.
[14] R. Attana, J.J. Silber, J. Anunziata, J. Am. Chem. Soc. 101 (1979) 5186.
[15] S. Viskocil, S. Jaracz, M. Smrcina, M. Sticha, V. Hanus, M. Polasek, P. Kocovsky, J.
Org. Chem. 63 (1998) 7727.
c = 30.628(2) Å,
a
= 90.00, b = 90.00,
c
= 90.00, V = 1223.66(16) Å,
T = 298(2) K. Of the
Z = 4,
q
c = 1.185 mg mꢂ3
,
l
= 0.08 mmꢂ1
,
12 650 reflections collected, 8389 were unique (Rint = 0.0311).
Refinement on all data converged at R1 = 0.0489, wR2 = 0.1142.