Palladium-catalyzed amination of allyl alcohols

Article abstract of DOI:10.1021/jo2014438

An efficient catalytic amination of aryl-substituted allylic alcohols has been developed. The complex [(η³-allyl)PdCl]₂ modified by a bis phosphine ligand, L, has been used as catalyst in the reaction that afforded a wide range of allyl amines in good to excellent yield under mild conditions.

Full text of DOI:10.1021/jo2014438

NOTE
pubs.acs.org/joc
Palladium-Catalyzed Amination of Allyl Alcohols
Raju Ghosh and Amitabha Sarkar*
Department of Organic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
S Supporting Information
b
ABSTRACT: An efficient catalytic amination of aryl-substituted allylic
alcohols has been developed. The complex [(η3-allyl)PdCl]2 modified by
a bis phosphine ligand, L, has been used as catalyst in the reaction that
afforded a wide range of allyl amines in good to excellent yield under mild
conditions.
llyl amines are important building blocks for various biolo-
gically active compounds and advanced intermediates in
the bis-phosphane ligand, L (entry 16). We also studied the
influence of different solvents on the reaction. Dioxane was
found to be a superior solvent compared to toluene, DMF, and
CH3CN (entries 10À12). The temperature around 80 °C was
found to be optimal for this reaction. The yield decreased with
lowering the temperature (entry 14). We observed that the
amount of solvent had a marked influence on the yield. Use of
0.2 mL of solvent for 1.0 mmol of cinnamyl alcohol afforded the
corresponding monoallylamine (entry 2) in better yield than
when the solvent volume was increased to 1.0 mL (entry 13).
Also, under solvent-free conditions this catalytic system furn-
ished N-cinnamylaniline in 87% yield (entry 15). We decided to
retain a minimal volume of solvent dioxane to ensure even mixing
of reactants, especially when one of them was a solid.
A
total synthesis of natural products1 and especially those involving
ring-closing metathesis.2 Therefore, their synthesis is still an
important area of activity. Although catalytic CÀN bond forma-
tion using nucleophilic attack on an η3-allyl palladium complex
has been widely used to this end,3 activated derivatives of allyl
alcohol (esters, carbonates, carbamates, phosphates, halides etc)4
and allyl alcohol with activators5 have only been chosen as
substrates. Use of allyl alcohol is limited by its reactivity despite
the economical and ecological advantage of this reaction that
only produces water as by product.6 Of late, a few reports have
appeared where allyl alcohol has indeed been used as a substrate
in Pd-catalyzed amination reactions.7,8 The conditions, especially
the ligands on palladium in such instances, are less common. It is
in this context that we report a highly efficient direct catalytic
amination of aryl-substituted allylic alcohols under mild condi-
tion using a combination of [(η3-allyl)PdCl]2 and a chelating P,
NÀP ligand developed by us.9
Using the optimized conditions with [(η3-allyl)PdCl]2
(1.5 mol %) and ligand (3.0 mol %) in dioxane (0.2 mL), we
conducted allylic amination reaction of a large number of
electronically and structurally diverse allyl alcohols with variously
substituted arylamines (Table 2). Substituted cinnamyl alcohols
in combination with aniline, p-anisidine, m-acetylaniline, and
2-naphthylamine afforded the corresponding monoallylamine in
good to excellent yield. Both the trans- and cis-cinnamyl alcohol
afforded the allylated product as the trans-isomer in very good
yield (entry 6), suggesting involvement of the same π-allyl
complex. No product was obtained from 4-nitroaniline (entry 5)
presumably due to the strong electron-withdrawing nature of
nitro group, which renders the aniline less nucleophilic. 2-Meth-
oxycinnamyl alcohol afforded the corresponding monoallylani-
line in good yield (entries 14 and 15). Ortho-substituted anilines
gave high yield of the desired products (entries 16 and 17),
although sterically demanding 2,6-disubstituted aniline did not
participate in the reaction. When we used benzyl amine as a
nucleophile very poor yield of product was obtained (entry 19).10
The bidentate phosphine ligand (L) on treatment with
[(η3-allyl)PdCl]2 in dichloromethane followed by addition of
the Ag salt afforded a 16e complex with deep magenta color (1a)
(Scheme 1). The molecular structure of the palladium complex
(1a) was determined by single-crystal X-ray analysis; the single
crystal of the air stable complex (1a) was grown from acetone/
hexane (see the Supporting Information).
We selected cinnamyl alcohol (2a) and p-anisidine (3b) as
typical coupling partners during optimization study. The molar
ratio of metal and ligand, the effect of different solvents, and
comparison of different Pd precursors were examined. The
results are summarized in Table 1. The comparative study reveals
that [(η3-allyl)PdCl]2 (entry 2) worked better as the catalyst
precursor than Pd(OAc)2, Pd2(dba)3, Pd(CH3CN)2Cl2, and
PdCl2 (entries 6À9). The use of a phosphane/Pd molar ratio
of 1:1 was found to be optimal for this catalytic system (entry 2).
It was observed that the presence of excess ligand suppressed the
reaction (entry 5). This reaction did not take place in absence of
Received: July 13, 2011
Published: September 05, 2011
r
2011 American Chemical Society
8508
dx.doi.org/10.1021/jo2014438 J. Org. Chem. 2011, 76, 8508–8512
|

The Journal of Organic Chemistry
NOTE
Scheme 1. Synthesis of Palladium Complex
Table 2. Amination of Allyl Alcohols with Arylaminea
Table 1. Optimization of Amination of Cinnamyl Alcohol
with p-Anisidinea
entry
Pd precursor (mol %)
ligand (mol %)
solvent
yield (%)
1
[(η3-allyl)PdCl]2 (1.0)
[(η3-allyl)PdCl]2 (1.5)
[(η3-allyl)PdCl] (2.0)
[(η3-allyl)PdCl]2 (1.5)
[(η3-allyl)PdCl]2 (1.5)
Pd(OAc)2 (3.0)
2.0
3.0
4.0
1.5
6.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
0
dioxane
dioxane
dioxane
dioxane
dioxane
dioxane
dioxane
dioxane
dioxane
toluene
DMF
81
89
90
63
37
68
57
31
5
2
3
4
5
6
7
Pd2dba3 (3.0)
8
Pd(CH3CN)2Cl2 (3.0)
9
PdCl2 (3.0)
10
11
12
13b
14c
15
16
[(η3-allyl)PdCl]2 (1.5)
[(η3-allyl)PdCl]2 (1.5)
[(η3-allyl)PdCl]2 (1.5)
[(η3-allyl)PdCl]2 (1.5)
[(η3-allyl)PdCl]2 (1.5)
[(η3-allyl)PdCl]2 (1.5)
[(η3-allyl)PdCl]2 (1.5)
84
84
85
62
78
87
0
CH3CN
dioxane
dioxane
neat
dioxane
a Reaction conditions: cinnamyl alcohol (1.0 mmol), p-anisidine (1.5
mmol), solvent (0.2 mL); argon atmosphere for 6 h. b 1.0 mL of solvent
was used. c At 70 °C.
Encouraged by this result, we extended allylic amination of
arylallyl alcohol with heteroarylamines. Imidazole and pyrazole
afforded almost quantitative yields of product with cinnamyl
alcohol and its analogues (Table 3). Sterrically more hindered
heteroaryl amines such as carbazole and indole were unreactive
under these conditions (entries 9 and 10). Allylic substitution
reaction of a secondary aliphatic amine produced a relatively
lower yield of the product (entry 11).
It has been reported in literature that sp2-hybridized phos-
phorus with increased π-acidity is a better donor for Pd-catalyzed
allylation of amines.7d,g The ligand (L) described in this paper
resembles, to an extent, the ligand DPEphos featuring two
phosphorus on a flexible diphenyl ether backbone. The paper,8b
however, reports on catalysis by Pt while Pd is ineffective. In our
case, the reaction is catalyzed by palladium in combination with a
bidentate phosphine ligand where one of the two phosphorus
atom is linked to a nitrogen. The ligand bite angle is 94° which is
smaller than the angle commonly found with catalytically active
complexes.8a,b
a Reaction conditions: allyl alcohol (1.0 mmol), amine (1.5 mmol),
[(η3-allyl)PdCl]2 (1.5 mol %), L (3.0 mol %), dioxane (0.2 mL); argon
atmosphere. b 0.1 mL of dioxane was used.
under mild conditions that provides an excellent yield of desired
monoallylamine. The reaction proceeded without any activator
In summary, we have developed an efficient, direct, catalytic
amination of aryl-substituted allylic alcohols with aromatic amines
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NOTE
Table 3. Amination of Allyl Alcohols with Heteroarylaminea
added BuLi (6.56 mL, 10.5 mmol, 1.60 M in hexane) dropwise at
À78 °C. The mixture was then stirred for 2 h at À78 °C. Chlorodiphe-
nylphosphine (1.94 mL, 10.5 mmol) in THF (5 mL) was then added
dropwise and the mixture stirred for 3 h. The mixture was then warmed
to rt and stirred for a further 3 h. It was then quenched with saturated
NH4Cl solution at 0 °C and extracted with diethyl ether (2 Â 100 mL).
The combined organic layer was washed subsequently with water and
brine and dried over anhydrous Na2SO4. Evaporation of solvent under
reduced pressure gave the crude product. Purification by flash column
chromatography (silica gel, 12% dichloromethane/petroleum ether)
afforded L as a white solid (607.0 mg, 25%).
n
General Procedure for Catalytic Reactions. A solution of
ligand (14.6 mg, 0.03 mmol), [(η3-allyl)PdCl]2 (5.5 mg, 0.015 mmol),
cinnamyl alcohol (1.0 mmol), and amine (1.5 mmol) in dioxane
(0.2 mL) was stirred under argon atmosphere at 80 °C for 2.5À8.0 h
(depending on substrate). The reaction mixture was then cooled to rt,
diluted with DCM (5 mL), and filtered through a pad of Na2SO4. The
filtrate was evaporated under reduced pressure, and the residue was purified
by flash column chromatography on silica gel (230À400 mesh) using ethyl
acetate/petroleum ether or methanol/dichloromethane as a eluent.
N-Cinnamylaniline (4a)8b. Light-yellowish oil. 1H NMR (300 MHz,
CDCl3): δ 7.43À7.21 (m, 7H), 6.80À6.64 (m, 4H), 6.37 (td, J = 15.9,
5.7 Hz, 1H), 3.97 (dd, J = 5.7, 1.2 Hz, 2H), 3.88 (bs, 1H). 13C NMR (75
MHz, CDCl3): δ 147.6, 136.9, 132.0, 129.4, 128.7, 127.7, 126.8, 126.5,
118.2, 113.6, 46.7.
N-Cinnamyl-4-methoxyaniline (4b)8a. White-yellowish solid. 1H NMR
(300 MHz, CDCl3): δ 7.38À7.22 (m, 5H), 6.79 (dd, J = 6.7, 2.2 Hz, 2H),
6.63 (dd, J = 6.6, 2.3 Hz, 2H), 6.58(s, 1H), 6.33 (td, J = 15.9, 5.8 Hz, 1H),
3.88 (dd, J = 5.8, 1.3 Hz, 2H), 3.74 (s, 3H). 13C NMR (75 MHz, CDCl3): δ
152.5, 142.1, 137.0, 131.7, 128.7, 127.6, 127.3, 126.4, 115.0, 114.7,
55.9, 47.4.
N-Cinnamyl-3-acetylaniline (4c)11. Yellow oil. 1H NMR (300 MHz,
CDCl3): δ 7.39À7.24 (m, 8H), 6.87À6.84 (m, 1H), 6.63 (d, J = 15.9 Hz,
1H), 6.31 (td, J = 15.9, 5.7 Hz, 1H), 3.97 (dd, J = 5.7, 1.4 Hz, 2H), 2.57
(s, 3H). 13C NMR (75 MHz, CDCl3): δ 198.7, 148.3, 138.3, 136.8,
131.9, 129.4, 128.7, 127.7, 126.5, 126.4, 118.0, 117.8, 111.9, 46.1, 26.8.
N-Cinnamyl-2-naphthylamine (4d). White solid. 1H NMR (300
MHz, CDCl3): δ 7.74À7.66 (m, 3H), 7.44À7.26 (m, 7H), 6.98À6.93
(m, 2H), 6.71 (d, J = 15.9 Hz, 1H), 6.41 (td, J = 15.9, 5.8 Hz, 1H), 4.08
(dd, J = 5.8, 1.4 Hz, 2H). 13C NMR (75 MHz, CDCl3): δ 145.7, 136.9,
135.3, 131.9, 129.1, 128.7, 127.8, 127.7, 126.7, 126.5, 126.1, 122.2, 118.1,
105.1, 46.3. HRMS (ESI): calcd for C19H18N ([M + H]+) 260.1439,
found 260.1434. Mp: 45 °C.
a Reaction conditions: allyl alcohol (1.0 mmol), amine (1.5 mmol), [(η3-
allyl)PdCl]2 (1.5 mol %), L (3.0 mol %), dioxane (0.2 mL); argon
atmosphere.
N-(3-m-Anisylallyl)aniline (4f). Yellow oil. 1H NMR (300 MHz,
CDCl3): δ 7.17À7.10 (m, 3H), 6.89 (d, J = 7.7 Hz, 1H), 6.83 (s, 1H),
6.73À6.63 (m, 4H), 6.51 (d, J = 15.9 Hz, 1H), 6.25 (td, J = 15.8, 5.8 Hz,
1H), 3.86 (dd, J = 5.8, 1.2 Hz, 2H), 3.73 (s, 3H). 13C NMR (75 MHz,
CDCl3): δ 159.9, 147.4, 138.4, 132.0, 129.7, 129.4, 127.0, 119.1, 118.4,
113.8, 113.4, 111.8, 55.3, 46.8. HRMS (ESI): calcd for C16H18NO ([M +
H]+) 240.1388, found 240.1383.
and produced water as the sole coproduct, representing an
inexpensive and environmentally friendly protocol for allyl amine
synthesis.
’ EXPERIMENTAL SECTION
N-(3-m-Anisylallyl)-4-methoxyaniline (4g). Yellow oil. 1H NMR
(300 MHz, CDCl3): δ 7.14 (t, J = 8.0 Hz, 1H), 6.89 (d, J = 7.7 Hz,
1H), 6.83 (s, 1H), 6.74À6.69 (m, 3H), 6.6À6.56 (m, 2H), 6.51 (d, J =
15.9 Hz, 1H), 6.25 (td, J = 15.9, 5.7 Hz, 1H), 3.81 (dd, J = 5.7, 1.1 Hz,
2H), 3.73 (s, 3H), 3.67 (s, 3H). 13C NMR (75 MHz, CDCl3): δ 159.9,
152.5, 142.2, 138.5, 131.5, 129.7, 127.8, 119.1, 115.0, 114.6, 113.3,
111.8, 55.9, 55.3, 47.4. HRMS (ESI): calcd for C17H20NO2 ([M +
H]+) 270.1494, found 270.1489.
General Information. Unless otherwise noted, all starting materials
were obtained from commercial suppliers (except entries 2b, 2c, 2d, and 2e,
Table 2). Organic solvents were dried and distilled as described elsewhere.
All reactions were carried out in an oven-dried flask under argon atmo-
sphere. Column chromatography was performed with silica gel 230À400
1
mesh. All H NMR, 13C NMR, and 31P NMR spectra were recorded in
CDCl3 or CD2Cl2 solution and are reported in ppm (δ). HRMS (ESI)
spectra were recorded on micromass, Q-Tofmicro. X-ray single-crystal data
were collected using Mo Kα (λ = 0.7107 Å) radiation. Data collection, data
reduction, and structure solution/refinement were carried out using the
software package of BRUKER APEX II. The single-crystal structure of the
complex (1a) was solved by direct methods and refined in a routine manner.
Preparation of Ligand (L). To a stirred solution of 7-bromoindole
(980.0 mg, 5 mmol) in THF (25 mL), under argon atmosphere, was
N-(3-m-Anisylallyl)-3-acetylaniline (4h). Yellow oil. 1H NMR
(500 MHz, CDCl3): δ 7.29À7.21 (m, 4H), 6.96 (d, J = 8.0 Hz, 1H),
6.90 (s, 1H), 6.84 (dd, J = 7.5, 2.0 Hz, 1H), 6.80 (dd, J = 8.0, 2.0 Hz,
1H), 6.60 (d, J = 15.5 Hz, 1H), 6.30 (td, J = 15.5, 5.5 Hz, 1H), 4.05
(bs, 1H), 3.98 (dd, J = 5.5, 1.1 Hz, 2H), 3.80 (s, 3H), 2.57 (s, 3H).
13C NMR (125 MHz, CDCl3): δ 198.7, 160.0, 148.3, 138.3, 138.3,
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NOTE
131.8, 129.7, 129.5, 126.9, 119.1, 118.1, 117.8, 113.4, 112.0, 111.9,
55.4, 46.1, 26.8. HRMS (ESI): calcd for C18H19NNaO2 ([M +
Na]+) 304.1313, found 304.1314.
2H). 13C NMR (75 MHz, CDCl3): δ 137.2, 135.8, 133.8, 129.7, 128.8,
128.4, 126.7, 123.8, 119.1, 49.1. Mp. 48.0 °C.
N-Cinnamylpyrazole (5b). Light yellowish oil. 1H NMR (300 MHz,
CDCl3): δ 7.27À7.12 (m, 5H), 6.31 (d, J = 16.0 Hz, 1H), 6.19 (td, J =
15.9, 5.4 Hz, 1H), 5.76 (s, 1H), 4.72 (d, J = 5.4 Hz, 2H), 2.17 (s, 3H),
2.16 (s, 3H). 13C NMR (75 MHz, CDCl3): δ 147.4, 139.5, 136.3, 132.4,
128.6, 127.9, 126.6, 124.5, 105.6, 51.1, 13.4, 11.1. HRMS (ESI): calcd for
C14H17N2 ([M + H]+) 213.1392, found 213.1385.
N-(3-m-Anisylallyl)-2-naphthylamine (4i). Light yellow oil. 1H
NMR (300 MHz, CDCl3): δ 7.63À7.55 (m, 3H), 7.30 (t, J = 7.5 Hz,
1H), 7.17À7.12 (m, 2H), 6.91À6.84 (m, 4H), 6.72 (dd, J = 8.2, 2.3 Hz,
1H), 6.56 (d, J = 15.9 Hz, 1H), 6.31 (td, J = 15.9, 5.9 Hz, 1H), 3.97 (dd,
J = 5.9, 0.8 Hz, 2H), 3.72 (s, 3H). 13C NMR (75 MHz, CDCl3): δ 159.9,
144.9, 138.3, 135.1, 132.2, 129.7, 129.2, 128.1, 127.8, 126.5, 126.3, 122.5,
119.2, 118.3, 113.5, 111.8, 106.1, 55.3, 46.8. HRMS (ESI): calcd for
C20H20NO ([M + H]+) 290.1545, found 290.1538.
N-(3-m-Anisylallyl)imidazole (5c). Colorless oil. 1H NMR (300
MHz, CDCl3): δ 7.74 (s, 1H), 7.25 (t, J = 8.0 Hz, 1H), 7.13 (s, 1H),
6.99À6.95 (m, 2H), 6.90 (s, 1H), 6.84 (d, J = 8.2 Hz, 1H), 6.52 (d, J =
15.8 Hz, 1H), 6.28 (td, J = 15.8, 6.1 Hz, 1H), 4.74 (d, J = 6.1 Hz, 2H),
3.81(s, 3H). 13C NMR (75 MHz, CDCl3): δ 160.0, 137.2, 137.0, 134.0,
129.8, 128.9, 123.8, 119.3, 119.2, 114.1, 112.0, 55.3, 49.2. HRMS (ESI):
calcd for C13H15N2O ([M + H]+) 215.1184, found 215.1179.
N-(3-m-Anisylallyl)pyrazole (5d). Light yellowish oil. 1H NMR (300
MHz, CDCl3): δ 7.28À7.19 (m, 1H), 6.95 (d, J = 7.7 Hz, 1H), 6.89 (d,
J = 2.0 Hz, 1H), 6.80 (dd, J = 8.2, 1.9 Hz, 1H), 6.38 (d, J = 16.0 Hz, 1H),
6.30 (td, J = 16.0, 4.9 Hz, 1H), 5.86 (s, 1H), 4.80 (d, J = 4.9 Hz, 2H), 3.83
(s, 3H), 2.27 (s, 3H), 2.26 (s, 3H). 13C NMR (75 MHz, CDCl3): δ
159.9, 147.5, 139.4, 137.8, 132.2, 129.6, 124.9, 119.3, 113.7, 111.8, 105.6,
55.3, 51.1, 13.5, 11.1. HRMS (ESI): calcd for C15H19N2O ([M + H]+)
243.1497, found 243.1492.
N-(3-p-Tolylallyl)aniline (4j)12. Yellow oil. 1H NMR (300 MHz,
CDCl3): δ 7.21À7.10 (m, 4H), 7.04 (d, J = 8.0 Hz, 2H), 6.71À6.63
(m, 3H), 6.52 (d, J = 15.9 Hz, 1H), 6.21 (td, J = 15.9, 5.9 Hz, 1H), 3.85
(dd, J = 5.9, 1.2 Hz, 2H), 2.26 (s, 3H). 13C NMR (75 MHz, CDCl3): δ
147.6, 137.5, 134.1, 131.9, 129.4, 126.4, 125.6, 118.2, 113.7, 46.8, 21.3.
N-(3-p-Tolylallyl)-4-methoxyaniline (4k). Light yellow solid. 1H NMR
(300 MHz, CDCl3): δ 7.19 (d, J = 8.1 Hz, 2H), 7.05 (d, J = 7.9 Hz, 2H),
6.73 (dd, J = 6.7, 2.2 Hz, 2H), 6.59À6.49 (m, 3H), 6.21 (td, J = 15.9, 5.9
Hz, 1H), 3.80 (dd, J = 5.9, 1.3 Hz, 2H), 2.26 (s, 3H). 13C NMR (75 MHz,
CDCl3): δ 152.4, 142.4, 137.4, 134.2, 131.6, 129.4, 126.3, 115.0, 114.6,
55.9, 47.5, 21.3. HRMS (ESI): calcd for C17H20NO ([M + H]+)
254.1545, found 254.1538. Mp: 75 °C.
1
N-(3-p-Tolylallyl)imidazole (5e). Solid. 1H NMR (300 MHz, CDCl3): δ
7.72 (d, J = 6.6 Hz, 1H), 7.28 (d, J = 8.0 Hz, 2H), 7.15 (d, J = 8.3 Hz, 3H),
6.99 (s, 1H), 6.54 (d, J = 15.8 Hz, 1H), 6.24 (td, J = 15.8, 6.0 Hz, 1H), 4.74
(d, J = 6.0 Hz, 2H), 2.35 (s, 3H). 13C NMR (75 MHz, CDCl3): δ 138.4,
137.0, 134.1, 133.0, 129.5, 128.9, 126.6, 122.3, 119.2, 49.4, 21.3. HRMS
(ESI): calcd for C13H15N2 ([M + H]+) 199.1235, found 199.1230. Mp:
60.0 °C.
N-(3-p-Tolylallyl)-3-acetylaniline (4l). Light yellow solid. H NMR
(300 MHz, CDCl3): δ 7.20À7.15 (m, 5H), 7.04 (d, J = 8.0 Hz, 2H),
6.79À6.75 (m, 1H), 6.51 (d, J = 15.9 Hz, 1H), 6.17 (td, J = 15.9, 5.8 Hz,
1H), 3.88 (dd, J = 5.8, 1.2 Hz, 2H), 2.48 (s, 3H), 2.25 (s, 3H). 13C NMR
(75 MHz, CDCl3): δ 198.7, 148.3, 138.3, 137.6, 134.0, 132.0, 129.5, 129.4,
126.4, 125.3, 118.1, 117.9, 112.0, 46.3, 26.9, 21.3. HRMS (ESI): calcd for
C18H19NNaO ([M + Na]+) 288.1364, found 288.1364. Mp: 78 °C.
1
N-(3-p-Tolylallyl)pyrazole (5f). Light yellow oil. 1H NMR (300 MHz,
CDCl3): δ 7.23 (d, J = 8.0 Hz, 2H), 7.10 (d, J = 8.0 Hz, 2H), 6.37 (d,
J = 15.9 Hz, 1H), 6.22 (td, J = 15.8, 5.6 Hz, 1H), 5.84 (s, 1H), 4.78 (d, J =
5.6 Hz, 2H), 2.32 (s, 3H), 2.25 (s, 3H), 2.24 (s, 3H). 13C NMR (75
MHz, CDCl3): δ 147.4, 139.3, 137.8, 133.6, 132.2, 129.3, 126.5, 123.6,
105.5, 51.2, 21.3, 13.5, 11.1. HRMS (ESI): calcd for C15H19N2
([M + H]+) 227.1548, found 227.1543.
N-(3-o-Anisylallyl)-4-methoxyaniline (4m). Yellow solid. H NMR
(300 MHz, CDCl3): δ 7.46 (dd, J = 7.6, 1.4 Hz, 1H), 7.28À7.22 (m,
1H), 7.01À6.89 (m, 3H), 6.86À6.80 (m, 2H), 6.71À6.66 (m, 2H), 6.39
(td, J = 15.9, 6.1 Hz, 1H), 3.93 (dd, J = 6.1, 1.4 Hz, 2H), 3.87 (s, 3H), 3.78
(s, 3H). 13C NMR (75 MHz, CDCl3): δ 156.7, 152.4, 142.4, 128.7, 128.1,
127.0, 126.7, 126.1, 120.8, 115.0, 114.6, 111.0, 55.9, 55.5, 47.9. HRMS (ESI):
calcd for C17H20NO2 ([M + H]+) 270.1494, found 270.1487. Mp: 69 °C.
N-(3-o-Anisylallyl)-3-acetylaniline (4n). Light yellowish oil. 1H NMR
(300 MHz, CDCl3): δ 7.39 (dd, J = 7.6, 1.4 Hz, 1H), 7.29À7.18 (m, 4H),
6.97À6.82 (m, 4H), 6.30 (td, J = 15.9, 6.0 Hz, 1H), 3.96 (dd, J = 6.0, 1.4
Hz, 2H), 3.82 (s, 3H), 2.55 (s, 3H). 13C NMR (75 MHz, CDCl3): δ
198.8, 156.7, 148.3, 138.3, 129.4, 128.8, 127.2, 127.1, 127.1, 125.9, 120.8,
118.0, 117.9, 112.1, 111.0, 55.5, 46.7, 26.8. HRMS (ESI): calcd for
C18H19NNaO2 ([M + Na]+) 304.1313, found 304.1313.
N-Cinnamylmorpholine (5i)8b. Oil. 1H NMR (500 MHz, CDCl3): δ
7.37 (d, J = 8.0 Hz, 2H), 7.31 (t, J = 7.5 Hz, 2H), 7.24 (m, 1H), 6.53 (d, J =
16.0 Hz, 1H), 6.26 (td, J = 16.0, 6.5 Hz, 1H), 3.74 (t, J = 4.5 Hz, 4H), 3.16
(d, J = 6.5 Hz, 2H), 2.51 (m, 4H). 13C NMR (75 MHz, CDCl3): δ 136.9,
133.6, 128.7, 127.7, 126.5, 126.1, 67.1, 61.6, 53.8.
Typical Procedure for Synthesis of Complex 1a16. A solution
of ligand L (87.4 mg, 0.18 mmol) and [(η3-allyl)PdCl]2 (33.0 mg, 0.09
mmol) in dichloromethane (2.0 mL) was stirred for 1 h at rt. AgSbF6
(0.18 mmol, 62.0 mg) was then added, and the yellow solution became
magenta. Filtration of AgCl on Celite followed by evaporation of the
dichloromethane under reduced pressure affording 1a as a deep magenta
solid (125.0 mg, 80%) which was crystallized from acetone/hexane.
LÀPd Allyl Complex (1a)16. Deep magenta solid. 1H NMR (500 MHz,
CD2Cl2): δ 7.98 (d, J = 7.5 Hz, 1H), 7.55 (t, J = 7.5 Hz, 1H), 7.48 (t, J =
7.5 Hz, 2H), 7.42 (m, 3H), 7.35 (m, 5H), 7.28 (m, 2H), 7.22 (m, 4H),
7.07 (m, 5H), 6.91 (d, J = 2.0 Hz, 2H), 5.90 (m, 1H), 4.27 (m, 2H), 3.45
(m, 2H). 13C NMR (125 MHz, CD2Cl2): δ 133.2, 133.1, 133.0, 132.9,
132.8, 132.6, 132.5, 131.8, 131.6, 131.5, 131.4, 130.8, 130.6, 130.5, 130.4,
130.1, 129.9, 129.6, 129.5, 129.4, 129.3, 129.2, 129.1, 126.1, 124.7, 124.7,
124.6, 122.8, 122.7, 109.2, 75.0. 31P NMR (202.44 MHz, CD2Cl2): δ 62.3
(d, J = 74.9 Hz), 10.0 (d, J = 74.9 Hz). Anal. Calcd forC35H30F6NP2PdSb:
C, 48.39; H, 3.48; N, 1.61. Found: C, 48.35; H, 3.47; N, 1.59.
1
N-Cinnamyl-2-methylaniline (4o)13. Light-yellowish oil. H NMR
(300 MHz, CDCl3): δ 7.45 (d, J = 7.2 Hz, 2H), 7.37 (t, J = 7.0 Hz, 2H),
7.32À7.27 (m, 1H), 7.22À7.13 (m, 2H), 6.78À6.67 (m, 3H), 6.43 (td,
J = 15.9, 5.8 Hz, 1H), 4.04 (dd, J = 5.8, 1.1 Hz, 2H), 2.24 (s, 3H). 13C
NMR (75 MHz, CDCl3): δ 146.0, 137.0, 131.8, 130.2, 128.7, 127.7,
127.3, 127.2, 126.5, 122.2, 117.4, 110.3, 46.3, 17.7.
N-Cinnamyl-2-methoxyaniline (4p)14. Colorless oil. 1H NMR (300
MHz, CDCl3): δ 7.42 (d, J = 7.1 Hz, 2H), 7.35 (t, J = 7.1 Hz, 2H),
7.29À7.24 (m, 1H), 6.92 (m, 1H), 6.84 (d, J = 7.9 Hz, 1H), 6.76À6.65
(m, 3H), 6.40 (td, J = 15.9, 5.7 Hz, 1H), 4.00 (dd, J = 5.7, 1.0 Hz, 2H), 3.9
(s, 3H). 13C NMR (75 MHz, CDCl3): δ 147.1, 138.1, 137.1, 131.5,
128.7, 127.6, 127.4, 126.5, 121.4, 116.9, 110.4, 109.6, 55.5, 46.1.
N-Cinnamylbenzylamine (4r)8b. Oil. 1H NMR (300 MHz, CDCl3):
δ 7.38À7.22 (m, 10H), 6.55 (d, J = 15.9 Hz, 1H), 6.32 (td, J = 15.9, 6.2
Hz, 1H), 3.84 (s, 2H), 3.44 (dd, J = 6.2, 1.2 Hz, 2H), 1.88(bs, 1H). 13C
NMR (75 MHz, CDCl3): δ 140.3, 137.2, 131.6, 128.7, 128.6, 128.4,
128.4, 127.5, 127.2, 126.4, 53.4, 51.3.
’ ASSOCIATED CONTENT
N-Cinnamylimidazole (5a)15. Solid. 1H NMR (300 MHz, CDCl3):
δ 7.55 (s, 1H), 7.38À7.26 (m, 5H), 7.10 (s, 1H), 6.96 (s, 1H), 6.52
S
Supporting Information. Detailed experimental proce-
b
(d, J = 15.8 Hz, 1H), 6.27 (td, J = 15.8, 6.1 Hz, 1H), 4.70 (d, J = 6.1 Hz,
dures and characterization data for all compounds and CIF file
8511
dx.doi.org/10.1021/jo2014438 |J. Org. Chem. 2011, 76, 8508–8512

The Journal of Organic Chemistry
NOTE
of 1a. This material is available free of charge via the Internet at
http://pubs.acs.org.
’ AUTHOR INFORMATION
Corresponding Author
*E-mail: ocas@iacs.res.in.
’ ACKNOWLEDGMENT
We thank the DST funded National Single Crystal Diffract-
ometer Facility of IACS for crystal structure solution. R.G. is
thankful to CSIR, India, for his fellowship.
’ REFERENCES
(1) (a) Trost, B. M.; Crawley, M. L. Chem. Rev. 2003, 103, 2921. (b)
Johannsen, M.; Jørgensen, K. A. Chem. Rev. 1998, 98, 1689. (c) Cheikh,
R. B.; Chaabouni, R.; Laurent, A.; Mison, P.; Nafti, A. Synthesis 1983, 685.
(2) Nicolaou, K. C.; Bulger, P. G.; Sarlah, D. Angew. Chem., Int. Ed.
2005, 44, 4490.
(3) For reviews, see: (a) Tsuji, J. Transition Metal Reagents and
Catalysts; Wiley: New York, 2000. (b) Godleski, S. A. In Comprehensive
Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon Press: New
York, 1991; Vol. 3, p 585.
(4) References cited inYang, S.-C.; Hsu, Y.-C.; Gan, K.-H.
Tetrahedron 2006, 62, 3949.
(5) (a) Tao, Y.; Zhou, Y.; Qu, J.; Hidai, M. Tetrahedron Lett. 2010,
51, 1982. (b) Kimura, M.; Futamata, M.; Shibata, K.; Tamaru, Y. Chem.
Commun. 2003, 234. (c) Yang, S.-C; Tsai, Y.-C Organometallics 2001,
20, 763. (d) Yang, S.-C; Hung, C.-W. J. Org. Chem. 1999, 64, 5000.
(e) Masuyama, Y.; Kagawa, M.; Kurusu, Y. Chem. Lett. 1995, 1121.
(f) Yang, S.-C.; Chung, W.-H. Tetrahedron Lett. 1999, 40, 953. (g) Lu,
X.; Lu, L.; Sun, J. J. Mol. Catal. 1987, 41, 245.
(6) (a) Trost, B. M. Angew. Chem., Int. Ed. Engl. 1995, 34, 259.
(b) Trost, B. M. Science 1991, 254, 1471.
(7) (a) Tao, Y.; Wang, B.; Wang, B.; Qu, L.; Qu, J. Org. Lett. 2010,
12, 2726. (b) Usui, I.; Schmidt, S.; Keller, M.; Breit, B. Org. Lett. 2008,
10, 1207. (c) Mora, G.; Deschamps, B.; van Zutphen, S.; Le Goff, X. F.;
Ricard, L.; le Floch, P. Organometallics 2007, 26, 1846. (d) Thoumazet,
C.; Gr€utzmacher, H.; Deschamps, B.; Ricard, L.; le Floch, P. Eur. J. Inorg.
Chem. 2006, 3911. (e) Kinoshita, H.; Shinokubo, H.; Oshima, K. Org.
Lett. 2004, 6, 4085. (f) Kayaki, Y.; Koda, T.; Ikariya, T. J. Org. Chem.
2004, 69, 2595. (g) Ozawa, F.; Okamoto, H.; Kawagishi, S.; Yamamoto,
S.; Minami, T.; Yoshifuji, M. J. Am. Chem. Soc. 2002, 124, 10968.
(8) Even Pt-based catalyst has been developed to use the allyl alcohol
directly in catalytic amination; see: (a) Ohshima, T.; Miyamoto, Y.;
Ipposhi, J.; Nakahara, Y.; Utsunomiya, M.; Mashima, K. J. Am. Chem. Soc.
2009, 131, 14317. (b) Utsunomiya, M.; Miyamoto, Y.; Ipposhi, J.;
Ohshima, T.; Mashima, K. Org. Lett. 2007, 9, 3371.
(9) (a) Ghosh, R.; Adarsh, N. N.; Sarkar, A. J. Org. Chem. 2010,
75, 5320. (b) Ghosh, R.; Sarkar, A. J. Org. Chem. 2010, 75, 8283.
(10) In contrast to cinnamyl alcohol, allyl alcohol and crotyl alcohol
afforded the corresponding monoallylaniline in less than 50% yield. In
the case of crotyl alcohol, a regio-isomeric mixture (84:16) was obtained.
(11) Patil, N. T.; Wu, H.; Kadota, I.; Yamamoto, Y. J. Org. Chem.
2004, 69, 8745.
(12) Nishina, N.; Yamamoto, Y. Angew. Chem., Int. Ed. 2006, 45, 3314.
(13) Nishikata, T.; Lipshutz, B. H. Org. Lett. 2009, 11, 2377.
(14) Wagh, Y. S.; Sawant, D. N.; Tambade, P. J.; Dhake, K. P.;
Bhanage, B. M. Tetrahedron 2011, 67, 2414.
(15) Baggaley, K. H.; Heald, M.; Hindley, R. M.; Morgan, B.; Tee,
J. L.; Green, J. J. Med. Chem. 1975, 18, 833.
(16) The procedure was adopted from ref 7d.
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