Enantioselective allylic amination of morita - baylis - hillman carbonates catalysed by modified cinchona alkaloids

Article abstract of DOI:10.1002/ejoc.200900944

An efficient procedure for the asymmetric allylic amination of Morita - Baylis - Hillman carbonates with cyclic imides catalysed by commercially available cinchona alkaloids is reported. It proves to be a facile protocol that affords α-methylene β-amino e

Full text of DOI:10.1002/ejoc.200900944

FULL PAPER
DOI: 10.1002/ejoc.200900944
Enantioselective Allylic Amination of Morita–Baylis–Hillman Carbonates
Catalysed by Modified Cinchona Alkaloids
Shan-Jun Zhang,[a,b] Hai-Lei Cui,[b] Kun Jiang,[b] Rui Li,*[a] Zhen-Yu Ding,[a] and
Ying-Chun Chen*[a,b]
Keywords: Organocatalysis / Amination / Alkaloids / Asymmetric catalysis
An efficient procedure for the asymmetric allylic amination
ene β-amino esters with good-to-excellent enantioselectivi-
of Morita–Baylis–Hillman carbonates with cyclic imides cata- ties (up to 94% ee) and in high yields (up to 97%).
lysed by commercially available cinchona alkaloids is re-
ported. It proves to be a facile protocol that affords α-methyl-
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2009)
tion that affords highly enantioenriched N-Boc-protected α-
methylene β-amino esters.[8] In addition, the Lewis base cat-
alysed direct asymmetric allylic amination of Morita–
Baylis–Hillman adducts is also a very attractive strategy,
however, only low-to-moderate enantioselectivities have
been obtained to date.[9]
Recently, we presented the results of some asymmetric
allylic alkylation reactions of Morita–Baylis–Hillman car-
bonates catalysed by cinchona alkaloid based tertiary
amines.[10] We then turned our attention to the development
of a highly enantioselective allylic amination reaction of
MBH carbonates operating through the same catalytic
mechanism that would be an effective process for producing
chiral α-methylene β-amino ester derivatives (Scheme 1).
Introduction
β-Amino carbonyl compounds containing an α-alkylid-
ene group are widely used in the synthesis of medicinal rea-
gents and natural products.[1] Therefore, the development
of protocols for the synthesis of these multifunctional com-
pounds has triggered increasing interest over the past few
decades. Apparently, the aza-Morita–Baylis–Hillman (aza-
MBH) reaction provides the most efficient approach to
these materials.[2] Since Perlmutter and Teo reported the
aza-MBH reaction between a preformed N-tosylimine and
methyl acrylate,[3] many groups have focused on the asym-
metric aza-MBH reaction of N-sulfonyl imines and various
activated olefins catalysed by diverse chiral tertiary phos-
phane, amine or bifunctional organocatalysts.[4] Raheem
and Jacobsen have also employed chiral thiourea derivatives
to catalyse the aza-MBH reaction between methyl acrylate
and N-nosylarylimines and high enantioselectivities and
fair yields were obtained.[5] Furthermore, Balan and
Adolfsson have reported a three-component reaction with
aryl aldehyde, pTsNH2, and methyl acrylate using the com-
bined Ti(OiPr)4 and β-ICD catalyst system.[6] However, the
reported methods were generally limited to specialized
imines bearing electron-withdrawing sulfonyl groups, which
might restrict their applications in organic synthesis. Thus,
some alternative processes for the preparation of α-alkylid-
ene-β-amino derivatives have been explored.[7] We have re-
ported an asymmetric tandem Mannich-type Wittig reac-
Scheme 1. Allylic amination of MBH carbonates to access chiral
α-methylene β-amino esters.
Results and Discussion
[a] State Key Laboratory of Biotherapy, West China Hospital,
Sichuan University,
In an initial study, a variety of nitrogen nucleophiles 1
(Figure 1)[11] were screened in the reaction with MBH car-
bonate 2a catalysed by quinidine in DCE (1,2-dichloro-
ethane) at room temperature. The results are summarized
in Table 1. Although all the tested nitrogen nucleophiles ex-
hibited good reactivity (Table 1, entries 1–8), in general,
better enantioselectivity was obtained when cyclic imide-
Chengdu 610041, P. R. China
[b] Key Laboratory of Drug-Targeting and Drug Delivery System
of the Education Ministry, Department of Medicinal Chemis-
try, West China School of Pharmacy, Sichuan University,
Chengdu 610041, P. R. China
Fax: +86-28-85502609
E-mail: ycchenhuaxi@yahoo.com.cn
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.200900944.
5804
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2009, 5804–5809

Allylic Amination of Morita–Baylis–Hillman Carbonates
type nitrogen sources 1d–h were used (entries 4–8).[9] Sub- and MBH carbonates 2 in DCE catalysed by 10 mol-% of
sequently, some modified cinchona alkaloids were tested in (DHQD)2PYR at 35 °C. The results are summarized in
the reaction of phthalimide 1d with MBH carbonate 2a (en- Table 2. For naphthaline-1,8-dicarboximide 1h, good-to-ex-
tries 9–11). To our gratification, of these alkaloids, cellent enantioselectivities and high yields were generally
(DHQD)2PYR exhibited the best enantiocontrol (entry 11). achieved with MBH carbonates bearing diverse electron-
Moreover, an even higher ee was observed when 1,8-naph- withdrawing or -donating aryl and heteroaryl groups
thalimide 1h was used (entry 12). (DHQ)2PYR gave the (Table 2, entries 1–13). On the other hand, phthalimides 1d,
product with the opposite configuration with a moderate 1e and 1f were also tested with a few MBH carbonates and
enantioselectivity (entry 13). It was also pleasing that the good results were delivered (entries 14–20). Nevertheless,
reaction could be more effectively conducted at 35 °C with- MBH carbonates bearing a β-alkyl substituent failed to af-
out affecting the enantioselectivity (entry 14). Although the ford the desired allylic amination products.
reaction time could be greatly shortened at 50 °C, the
enantioselectivity was also reduced (entry 15). When the re-
action was performed in a number of other solvents, similar
data were obtained (entries 16–19).
Table 2. Asymmetric allylic amination reaction of imides 1 with
MBH carbonates 2.[a]
Entry
R
1
t
[h]
3
Yield[b]
[%]
ee[c]
[%]
1
2
3
4
Ph
1h
1h
1h
1h
1h
1h
1h
1h
1h
1h
1h
1h
1h
1d
1d
1d
1e
1e
1e
1f
70
22
67
60
48
92
25
23
69
3a
3b
3c
3d
3e
3f
3g
3h
3i
92
97
94
96
94
95
96
89
95
95
96
92
90
90 (91)
92 (93)
91
91
92
90
94
91
89
91
93
93
90
90
93
90
88
82
80 (85)
82 (87)
89
89
90
Figure 1. The structures of various nitrogen nucleophiles.
1-naphthyl
p-ClC6H4
m-ClC6H4
o-ClC6H4
p-FC6H4
o-BrC6H4
o-O2NC6H4
3,4-Cl2C6H3
p-MeOC6H4
m-MeC6H4
p-MeC6H4
2-thienyl
Ph
o-BrC6H4
1-naphthyl
Ph
o-ClC6H4
o-BrC6H4
Ph
5[d]
6
Table 1. Screening studies of nitrogen nucleophiles in the allylic
amination of MBH carbonates.[a]
7
8
9
10
11
12
13
14[e]
15[e]
16
17
18
19
20
106
83
83
3j
3k
3l
40
3m
3n
3o
3p
3q
3r
3s
3t
Entry NuH Catalyst
Solvent
t
[h]
Yield[b]
[%]
ee[c]
[%]
47 (84)
29 (52)
18
28
30
1
2
3
4
5
6
7
8
1a
1b
1c
1d
1e
1f
1g
1h
1d
1d
1d
1h
1h
1h
1h
1h
1h
1h
1h
quinidine
quinidine
quinidine
quinidine
quinidine
quinidine
quinidine
quinidine
(DHQD)2AQN
(DHQD)2PHAL
(DHQD)2PYR
(DHQD)2PYR
(DHQ)2PYR
(DHQD)2PYR
(DHQD)2PYR
(DHQD)2PYR
(DHQD)2PYR
(DHQD)2PYR
(DHQD)2PYR
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
CHCl3
THF
dioxane
toluene
69
106
85
28
39
59
35
48
42
42
84
95
95
70
24
71
98
105
92
71
87
50
40
83
66
61
65
81
59
91
92
92
94
94
92
92
86
86
22
12
30
51
47
50
50
40
60
14
85
90
–72
90
84
85
91
90
88
26
30
92
86
90
87
[a] Unless otherwise noted, reactions were performed with
0.1 mmol of 1, 0.2 mmol of 2 and 0.01 mmol of (DHQD)2PYR in
1 mL of DCE at 35 °C. [b] Isolated yield. [c] Determined by chiral
HPLC analysis. [d] The absolute configuration of 3e was deter-
mined by X-ray analysis.[12] The other products were assigned by
analogy. [e] The data in parentheses were obtained at room temp.
9
10
11
12
13
14[d]
15[e]
16[d]
17[d]
18[d]
19[d]
As outlined in Scheme 2, the allylic products could be
smoothly transformed into more complex compounds. For
example, intramolecular radical cyclization of the product
3o proceeded efficiently in the presence of Bu3SnH and
AIBN with no impact on the enantiopurity of the reaction
and is thus a facile route to the interesting β-amino ester 4.
Also, the 1,3-dipolar cycloaddition reaction of the allylic
amination product 3n with chlorobenzaldoxime was per-
[a] Unless otherwise noted, the reactions were performed with
0.1 mmol of 1, 0.2 mmol of 2a and 0.01 mmol of catalyst in 1 mL
of solvent at room temp. [b] Isolated yield. [c] Determined by chiral
HPLC analysis. [d] At 35 °C. [e] At 50 °C.
Having established the optimal reaction conditions, the formed in DCM and the diastereomerically pure product 5
scope and limitation of the asymmetric allylic amination was isolated in high yield and with the ee value re-
reaction were investigated with a variety of cyclic imides tained.[10b,13]
Eur. J. Org. Chem. 2009, 5804–5809
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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S.-J. Zhang, H.-L. Cui, K. Jiang, R. Li, Z.-Y. Ding, Y.-C. Chen
FULL PAPER
1.0 mL/min, λ = 220 nm, t(major) = 28.32, t(minor) = 24.49 min].
1H NMR (400 MHz, CDCl3): δ = 8.58 (dd, J = 7.2, 1.2 Hz, 2 H),
8.19 (dd, J = 8.2, 1.0 Hz, 2 H), 7.75–7.71 (m, 2 H), 7.58–7.55 (m,
2 H), 7.36–7.28 (m, 3 H), 7.19 (t, J = 1.8 Hz, 1 H), 6.47 (d, J =
2.0 Hz, 1 H), 5.60 (d, J = 2.0 Hz, 1 H), 3.67 (s, 3 H) ppm. 13C
NMR (100 MHz, CDCl3): δ = 166.6, 164.3, 139.1, 137.7, 133.9,
131.5, 129.2, 128.5, 128.3, 127.8, 126.9, 122.8, 56.7, 52.0 ppm.
HRMS (ESI): calcd. for C23H18NO4
372.1247.
+ H 372.1236; found
Methyl
(R)-2-{[1,3-Dioxo-1H-benzo[de]isoquinolin-2(3H)-yl](1-
naphthyl)methyl}acrylate (3b): Rf = 0.3 (petroleum ether/EtOAc =
6:1); 97% yield. [α]2D0 = 125.5 (c = 0.44, CHCl3); 94% ee, deter-
mined by HPLC analysis [Daicel chiralpak AD, n-hexane/iPrOH
= 70:30, 1.0 mL/min, λ = 220 nm, t(major) = 15.15, t(minor) =
1
12.40 min]. H NMR (400 MHz, CDCl3): δ = 8.58 (d, J = 7.6 Hz,
2 H), 8.20 (d, J = 8.4 Hz, 2 H), 8.02 (d, J = 8.4 Hz, 1 H), 7.97 (s,
1 H), 7.86 (d, J = 7.6 Hz, 1 H), 7.81 (d, J = 8.4 Hz, 1 H), 7.76–
7.72 (m, 3 H), 7.51–7.43 (m, 3 H), 6.53 (s, 1 H), 5.53 (s, 1 H), 3.70
(s, 3 H) ppm. 13C NMR (50 MHz, CDCl3): δ = 166.6, 164.6, 138.4,
134.0, 133.8, 133.2, 131.7, 131.5, 131.4, 129.0, 128.7, 128.4, 127.8,
127.4, 127.0, 126.6, 125.5, 125.2, 123.2, 122.8, 54.0, 52.2 ppm.
HRMS (ESI): calcd. for C27H19NO4 + Na 444.1212; found
444.1176.
Scheme 2. Transformations of the allylic amination products.
Conclusions
We have developed an efficient and enantioselective al-
lylic amination of MBH carbonates catalysed by modified
cinchona alkaloids. A range of α-methylene β-amino esters
have been obtained with good-to-excellent enantioselectivi-
ties (up to 94% ee) and high yields (up to 97%). The allylic
products could be smoothly transformed into more com-
plex compounds in good yields without any racemization.
Further studies on cinchona alkaloid catalysed asymmetric
allylic alkylation reactions are under way in our laboratory.
Methyl (R)-2-{(4-Chlorophenyl)[1,3-dioxo-1H-benzo[de]isoquinolin-
2(3H)-yl]methyl}acrylate (3c): Rf = 0.4 (petroleum ether/EtOAc =
8:1); 94% yield. [α]2D0 = 79.1 (c = 0.38, CHCl3); 91% ee, determined
by HPLC analysis [Daicel chiralcel OD, n-hexane/iPrOH = 70:30,
1.0 mL/min, λ = 220 nm, t(major) = 11.55, t(minor) = 13.62 min].
1H NMR (400 MHz, CDCl3): δ = 8.58 (dd, J = 7.2, 0.8 Hz, 2 H),
8.21 (dd, J = 8.4, 1.2 Hz, 2 H), 7.74 (dd, J = 8.4, 0.8 Hz, 2 H),
7.52–7.49 (m, 2 H), 7.32–7.30 (m, 2 H), 7.18 (t, J = 2.0 Hz, 1 H),
6.48 (d, J = 2.0 Hz, 1 H), 5.60 (d, J = 2.0 Hz, 1 H), 3.68 (s, 3
H) ppm. 13C NMR (100 MHz, CDCl3): δ = 166.4, 164.3, 138.5,
136.3, 134.1, 133.7, 131.6, 131.5, 130.7, 128.6, 128.3, 128.0, 127.0,
122.7, 56.0, 52.1 ppm. HRMS (ESI): calcd. for C23H16ClNO4 + Na
428.0666; found 428.0634.
Experimental Section
General: 1H NMR spectra were recorded at 400 or 300 MHz
(Varian) and 13C NMR spectra at 50 or 100 MHz (Varian) with
tetramethylsilane as the internal standard. Chemical shifts are re-
ported in ppm downfield from CDCl3 (δ = 7.27 ppm) for 1H NMR
Methyl (R)-2-{(3-Chlorophenyl)[1,3-dioxo-1H-benzo[de]isoquinolin-
2(3H)-yl]methyl}acrylate (3d): Rf = 0.3 (petroleum ether/EtOAc =
8:1); 96% yield. [α]2D0 = 84.8 (c = 0.44, CHCl3); 89% ee, determined
by HPLC analysis [Daicel chiralpak AD, n-hexane/iPrOH = 90:10,
1.0 mL/min, λ = 220 nm, t(major) = 25.79, t(minor) = 24.20 min].
1H NMR (400 MHz, CDCl3): δ = 8.58 (dd, J = 7.4, 1.0 Hz, 2 H),
8.21 (dd, J = 8.4, 0.8 Hz, 2 H), 7.74 (dd, J = 8.0, 0.8 Hz, 2 H),
7.55–7.54 (m, 1 H), 7.45–7.43 (m, 1 H), 7.30–7.26 (m, 2 H), 7.18
(t, J = 1.8 Hz, 1 H), 6.50 (d, J = 2.0 Hz, 1 H), 5.63 (d, J = 2.0 Hz,
1 H), 3.68 (s, 3 H) ppm. 13C NMR (50 MHz, CDCl3): δ = 166.3,
164.3, 139.8, 138.3, 134.3, 134.1, 131.7, 129.7, 129.3, 128.5, 128.3,
128.0, 127.5, 127.4, 127.0, 122.6, 56.0, 52.2 ppm. HRMS (ESI):
calcd. for C23H16ClNO4 + Na 428.0666; found 428.0658.
and relative to the central CDCl3 resonance (δ = 77.0 ppm) for 13
C
NMR spectroscopy. Coupling constants are given in Hz. Optical
rotations were measured at 589 nm at 20 °C. Enantiomeric excesses
were determined by HPLC analysis using Chiralpak AD and Chi-
ralcel OD columns. DCE was distilled from CaH2. All other chemi-
cals were used as commercially available without further purifica-
tion. Cinchona alkaloid catalysts (DHQD)2PHAL, (DHQD)2PYR,
(DHQD)2AQN and (DHQ)2PYR were purchased from Aldrich
Chemical Company. Morita–Baylis–Hillman carbonates were pre-
pared according to the literature procedure.[14]
General Procedure for the Catalytic Allylic Amination of Morita–
Baylis–Hillman Carbonates: A mixture of cyclic imide 1 (0.1 mmol),
Methyl (S)-2-{(2-Chlorophenyl)[1,3-dioxo-1H-benzo[de]isoquinolin-
2(3H)-yl]methyl}acrylate (3e): Rf = 0.3 (petroleum ether/EtOAc =
8:1); 94% yield. [α]2D0 = –44.9 (c = 0.50, CHCl3); 93% ee, deter-
mined by HPLC analysis [Daicel chiralpak AD, n-hexane/iPrOH =
70:30, 1.0 mL/min, λ = 254 nm, t(major) = 11.45, t(minor) =
8.84 min]. 1H NMR (400 MHz, CDCl3): δ = 8.57 (d, J = 7.2 Hz, 2
H), 8.22 (d, J = 8.0 Hz, 2 H), 7.74 (t, J = 7.8 Hz, 2 H), 7.60–7.57
(m, 1 H), 7.42–7.35 (m, 2 H), 7.27–7.23 (m, 2 H), 6.54 (s, 1 H),
5.60 (s, 1 H), 3.70 (s, 3 H) ppm. 13C NMR (50 MHz, CDCl3): δ =
166.2, 164.3, 137.2, 135.5, 134.0, 133.8, 131.7, 131.0, 129.6, 129.1,
128.4, 127.2, 127.0, 126.6, 122.7, 54.9, 52.2 ppm. HRMS (ESI):
calcd. for C23H16ClNO4 + Na 428.0666; found 428.0677.
Morita–Baylis–Hillman carbonate
2 (0.2 mmol) and catalyst
(DHQD)2PYR (8.8 mg, 0.01 mmol) in anhydrous DCE (1 mL) was
stirred at 35 °C for a specified reaction time. Then the solvent was
removed in vacuo and the residue was purified by flash chromatog-
raphy on silica gel (petroleum ether/ethyl acetate) to give the prod-
uct 3.
Methyl (R)-2-{[1,3-Dioxo-1H-benzo[de]isoquinolin-2(3H)-yl](phen-
yl)methyl}acrylate (3a): Rf = 0.3 (petroleum ether/EtOAc = 10:1);
92% yield. [α]2D0 = 111.4 (c = 0.30, CHCl3); 90% ee, determined by
HPLC analysis [Daicel chiralpak AD, n-hexane/iPrOH = 90:10,
5806
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Eur. J. Org. Chem. 2009, 5804–5809

Allylic Amination of Morita–Baylis–Hillman Carbonates
Methyl (R)-2-{[1,3-Dioxo-1H-benzo[de]isoquinolin-2(3H)-yl](4-
126.9, 126.4, 122.8, 113.9, 56.3, 55.2, 52.0 ppm. HRMS (ESI):
calcd. for C24H19NO5 + Na 424.1161; found 424.1160.
fluorophenyl)methyl}acrylate (3f): Rf = 0.3 (petroleum ether/EtOAc
= 8:1); 95% yield. [α]2D0 = 123.4 (c = 0.40, CHCl3); 93% ee, deter-
mined by HPLC analysis [Daicel chiralcel OD, n-hexane/iPrOH =
70:30, 1.0 mL/min, λ = 254 nm, t(major) = 10.71, t(minor) =
14.35 min]. 1H NMR (400 MHz, CDCl3): δ = 8.58 (dd, J = 7.2,
1.2 Hz, 2 H), 8.21 (dd, J = 8.2, 1.0 Hz, 2 H), 7.74 (t, J = 7.8 Hz, 2
H), 7.59–7.55 (m, 2 H), 7.17 (t, J = 2.0 Hz, 1 H), 7.05–7.00 (m, 2
H), 6.46 (d, J = 2.0 Hz, 1 H), 5.58 (d, J = 2.0 Hz, 1 H), 3.67 (s, 3
H) ppm. 13C NMR (50 MHz, CDCl3): δ = 166.5, 164.7, 164.3,
159.8, 139.0, 134.0, 133.6, 133.5, 131.6, 131.3, 131.1, 128.3, 127.0,
126.7, 122.7, 115.6, 115.2, 56.1, 52.1 ppm. HRMS (ESI): calcd. for
C23H16FNO4 + Na 412.0961; found 412.0959.
Methyl
(R)-2-{[1,3-Dioxo-1H-benzo[de]isoquinolin-2(3H)-yl](m-
tolyl)methyl}acrylate (3k): Rf = 0.4 (petroleum ether/EtOAc =
10:1); 96% yield. [α]2D0 = 18.1 (c = 0.95, CHCl3); 90% ee, deter-
mined by HPLC analysis [Daicel chiralcel OD, n-hexane/iPrOH =
70:30, 1.0 mL/min, λ = 220 nm, t(major) = 14.14, t(minor) =
26.56 min]. 1H NMR (400 MHz, CDCl3): δ = 8.58 (dd, J = 7.4,
1.0 Hz, 2 H), 8.18 (dd, J = 8.4, 0.8 Hz, 2 H), 7.75–7.71 (m, 2 H),
7.38–7.35 (m, 2 H), 7.23 (t, J = 7.8 Hz, 1 H), 7.14 (s, 1 H), 7.09 (d,
J = 7.6 Hz, 1 H), 6.45 (d, J = 2.0 Hz, 1 H), 5.59 (d, J = 2.0 Hz, 1
H), 3.67 (s, 3 H), 2.32 (s, 3 H) ppm. 13C NMR (50 MHz, CDCl3):
δ = 166.6, 164.3, 139.2, 138.1, 137.6, 133.8, 131.5, 129.8, 128.6,
128.3, 126.9, 126.8, 126.3, 122.8, 56.8, 52.0, 21.5 ppm. HRMS
(ESI): calcd. for C24H19NO4 + Na 408.1212; found 408.1187.
Methyl (S)-2-{(2-Bromophenyl)[1,3-dioxo-1H-benzo[de]isoquinolin-
2(3H)-yl]methyl}acrylate (3g): Rf = 0.3 (petroleum ether/EtOAc =
8:1); 96% yield. [α]2D0 = –35.1 (c = 0.42, CHCl3); 93% ee, deter-
mined by HPLC analysis [Daicel chiralpak AD, n-hexane/iPrOH =
70:30, 1.0 mL/min, λ = 220 nm, t(major) = 13.60, t(minor) =
9.00 min]. 1H NMR (400 MHz, CDCl3): δ = 8.58 (dd, J = 7.4,
1.0 Hz, 2 H), 8.20 (dd, J = 8.4, 0.8 Hz, 2 H), 7.76–7.72 (m, 2 H),
7.59–7.55 (m, 2 H), 7.17–7.00 (m, 3 H), 6.46 (d, J = 2.0 Hz, 1 H),
5.58 (d, J = 2.0 Hz, 1 H), 3.67 (s, 3 H) ppm. 13C NMR (50 MHz,
CDCl3): δ = 166.1, 164.3, 137.3, 137.1, 134.0, 133.0, 131.7, 131.1,
129.3, 128.4, 127.2, 127.0, 124.1, 122.7, 57.4, 52.2 ppm. HRMS
(ESI): calcd. for C23H16BrNO4 + Na 472.0160; found 472.0192.
Methyl
(R)-2-{[1,3-Dioxo-1H-benzo[de]isoquinolin-2(3H)-yl](p-
tolyl)methyl}acrylate (3l): Rf = 0.3 (petroleum ether/EtOAc = 10:1);
92% yield. [α]2D0 = 120.0 (c = 0.28, CHCl3); 88% ee, determined by
HPLC analysis [Daicel chiralcel OD, n-hexane/iPrOH = 70:30,
1.0 mL/min, λ = 220 nm, t(major) = 20.82, t(minor) = 13.84 min].
1H NMR (400 MHz, CDCl3): δ = 8.57 (dd, J = 7.2, 1.2 Hz, 2 H),
8.18 (dd, J = 8.2, 1.0 Hz, 2 H), 7.72 (dd, J = 8.0, 0.8 Hz, 2 H), 7.46
(d, J = 8.4 Hz, 2 H), 7.15–7.14 (m, 3 H), 6.45 (d, J = 1.6 Hz, 1 H),
5.60 (d, J = 1.6 Hz, 1 H), 3.67 (s, 3 H), 2.32 (s, 3 H) ppm. 13C
NMR (50 MHz, CDCl3): δ = 166.6, 164.3, 139.2, 137.4, 134.7,
133.8, 131.5, 129.2, 129.1, 128.2, 126.9, 126.6, 122.8, 56.5, 52.0,
21.1 ppm. HRMS (ESI): calcd. for C24H19NO4 + Na 408.1212;
found 408.1212.
Methyl (R)-2-{[1,3-Dioxo-1H-benzo[de]isoquinolin-2(3H)-yl](2-ni-
trophenyl)methyl}acrylate (3h): Rf = 0.4 (petroleum ether/EtOAc =
5:1); 89% yield. [α]2D0 = 125.0 (c = 0.35, CHCl3); 90% ee, deter-
mined by HPLC analysis [Daicel chiralpak AD, n-hexane/iPrOH
= 70:30, 1.0 mL/min, λ = 220 nm, t(major) = 16.49, t(minor) =
Methyl (S)-2-{[1,3-Dioxo-1H-benzo[de]isoquinolin-2(3H)-yl](thio-
phen-2-yl)methyl}acrylate (3m): Rf = 0.3 (petroleum ether/EtOAc =
8:1); 90% yield. [α]2D0 = 330.8 (c = 0.85, CHCl3); 82% ee, deter-
mined by HPLC analysis [Daicel chiralpak AD, n-hexane/iPrOH
= 70:30, 1.0 mL/min, λ = 220 nm, t(major) = 13.19, t(minor) =
15.08 min]. 1H NMR (400 MHz, CDCl3): δ = 8.60 (dd, J = 7.2,
1.2 Hz, 2 H), 8.18 (dd, J = 8.4, 0.8 Hz, 2 H), 7.73 (dd, J = 8.0,
0.8 Hz, 2 H), 7.55 (t, J = 2.0 Hz, 1 H), 7.32–7.28 (m, 2 H), 7.00–
6.98 (m, 1 H), 6.50 (d, J = 2.4 Hz, 1 H), 5.90 (d, J = 2.0 Hz, 1 H),
3.64 (s, 3 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 166.1, 163.8,
139.1, 133.9, 131.5, 129.1, 128.2, 127.7, 126.9, 126.7, 126.2, 122.6,
52.0, 51.7 ppm. HRMS (ESI): calcd. for C21H15NO4S + Na
400.0619; found 400.0628.
1
12.28 min]. H NMR (400 MHz, CDCl3): δ = 8.56 (d, J = 7.6 Hz,
2 H), 8.21 (d, J = 8.4 Hz, 2 H), 7.95 (d, J = 8.0 Hz, 1 H), 7.78–
7.67 (m, 4 H), 7.57 (t, J = 7.6 Hz, 1 H), 7.45 (t, J = 7.6 Hz, 1 H),
6.54 (s, 1 H), 5.61 (d, J = 1.2 Hz, 1 H), 3.69 (s, 3 H) ppm. 13C
NMR (50 MHz, CDCl3): δ = 165.9, 164.4, 149.2, 137.3, 134.2,
132.9, 132.7, 131.8, 131.5, 131.3, 128.7, 128.4, 127.4, 127.0, 124.7,
122.4, 53.2, 52.3 ppm. HRMS (ESI): calcd. for C23H16N2O6 + Na
439.0906; found 439.0905.
Methyl (R)-2-{(3,4-Dichlorophenyl)[1,3-dioxo-1H-benzo[de]isoquin-
olin-2(3H)-yl]methyl}acrylate (3i): Rf = 0.3 (petroleum ether/EtOAc
= 8:1); 95% yield. [α]2D0 = 30.3 (c = 0.40, CHCl3); 90% ee, deter-
mined by HPLC analysis [Daicel chiralcel OD, n-hexane/iPrOH =
80:20, 1.0 mL/min, λ = 220 nm, t(major) = 13.24, t(minor) =
17.52 min]. 1H NMR (400 MHz, CDCl3): δ = 8.59 (dd, J = 7.2,
1.2 Hz, 2 H), 8.23 (dd, J = 8.0, 0.8 Hz, 2 H), 7.76 (dd, J = 8.0,
0.8 Hz, 2 H), 7.64 (s, 1 H), 7.41 (d, J = 1.2 Hz, 2 H), 7.18 (t, J =
1.8 Hz, 1 H), 6.51 (d, J = 2.0 Hz, 1 H), 5.64 (d, J = 2.0 Hz, 1 H),
3.69 (s, 3 H) ppm. 13C NMR (50 MHz, CDCl3): δ = 166.2, 164.2,
138.1, 137.9, 134.2, 132.5, 131.8, 131.6, 131.2, 130.3, 128.8, 127.5,
127.1, 122.5, 55.5, 52.2 ppm. HRMS (ESI): calcd. for
C23H15Cl2NO4 + Na 462.0276; found 462.0222.
Methyl
(R)-2-[(1,3-Dioxoisoindolin-2-yl)(phenyl)methyl]acrylate
(3n): Rf = 0.4 (petroleum ether/EtOAc = 10:1); 91% yield. [α]2D0
=
118.2 (c = 0.64, CHCl3); 85% ee, determined by HPLC analysis
[Daicel chiralcel OD, n-hexane/iPrOH = 70:30, 1.0 mL/min, λ =
254 nm, t(major)
= 6.85, t(minor) =
10.23 min]. 1H NMR
(400 MHz, CDCl3): δ = 7.85–7.82 (m, 2 H), 7.72–7.70 (m, 2 H),
7.45–7.30 (m, 5 H), 6.57 (s, 1 H), 6.40 (s, 1 H), 5.63 (s, 1 H), 3.71
(s, 3 H) ppm. 13C NMR (50 MHz, CDCl3): δ = 167.9, 166.1, 137.6,
137.0, 134.1, 131.9, 129.7, 128.7, 128.1, 123.4, 54.7, 52.2 ppm.
HRMS (ESI): calcd. for C19H15NO4 + Na 344.0899; found
344.0928.
Methyl
(R)-2-{[1,3-Dioxo-1H-benzo[de]isoquinolin-2(3H)-yl](4-
methoxyphenyl]methyl}acrylate (3j): Rf = 0.3 (petroleum ether/
EtOAc = 10:1); 95% yield. [α]2D0 = 112.6 (c = 0.45, CHCl3); 93%
ee, determined by HPLC analysis [Daicel chiralpak AD, n-hexane/
iPrOH = 80:20, 1.0 mL/min, λ = 220 nm, t(major) = 23.20,
t(minor) = 21.44 min]. H NMR (400 MHz, CDCl3): δ = 8.57 (dd,
J = 7.6, 1.2 Hz, 2 H), 8.18 (dd, J = 8.4, 1.2 Hz, 2 H), 7.72 (dd, J
= 8.0, 0.8 Hz, 2 H), 7.54–7.52 (m, 2 H), 7.13 (t, J = 2.2 Hz, 1 H),
Methyl
(S)-2-[(2-Bromophenyl)(1,3-dioxoisoindolin-2-yl)methyl]-
acrylate (3o): Rf = 0.4 (petroleum ether/EtOAc = 10:1); 93% yield.
[α]2D0 = 13.9 (c = 0.22, CHCl3); 87% ee, determined by HPLC analy-
sis [Daicel chiralpak AD, n-hexane/iPrOH = 90:10, 1.0 mL/min,
λ = 220 nm, t(major) = 21.19, t(minor) = 17.76 min]. 1H NMR
(400 MHz, CDCl3): δ = 7.85–7.82 (m, 2 H), 7.75–7.72 (m, 2 H),
7.59–7.50 (m, 2 H), 7.36–7.29 (m, 1 H), 7.20–7.16 (m, 1 H), 6.71
1
6.88–6.86 (m, 2 H), 6.43 (d, J = 2.0 Hz, 1 H), 5.59 (d, J = 2.0 Hz, (s, 1 H), 6.59 (d, J = 1.2 Hz, 1 H), 5.58 (d, J = 2.0 Hz, 1 H), 3.71
1 H), 3.78 (s, 3 H), 3.66 (s, 3 H) ppm. 13C NMR (50 MHz, CDCl3): (s, 3 H) ppm. 13C NMR (50 MHz, CDCl3): δ = 167.7, 165.7, 136.3,
δ = 166.6, 164.3, 159.1, 139.5, 133.9, 131.5, 130.8, 129.9, 128.3,
136.1, 134.2, 133.1, 131.7, 130.5, 129.7, 129.0, 127.4, 124.0, 123.5,
5807
Eur. J. Org. Chem. 2009, 5804–5809
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org

S.-J. Zhang, H.-L. Cui, K. Jiang, R. Li, Z.-Y. Ding, Y.-C. Chen
FULL PAPER
54.6, 52.3 ppm. HRMS (ESI): calcd. for C19H14NO4 + Na
422.0004; found 422.0002.
solution of compound 3o (18 mg, 0.045 mmol) and AIBN (1.5 mg,
0.009 mmol) in benzene . The solution was stirred at 90 °C for
about 6 h. Then the solvent was removed and the residue was puri-
fied by column chromatography (petroleum ether/ethyl acetate =
20:1) to afford the product 4 as a white solid (10.5 mg, 73%). Rf =
0.3 (petroleum ether/EtOAc = 10:1). [α]2D0 = –73.9 (c = 0.25,
CHCl3); 83% ee, determined by HPLC analysis [Daicel chiralpak
AD, n-hexane/iPrOH = 70:30, 1.0 mL/min, λ = 220 nm, t(major) =
9.54, t(minor) = 15.51 min]. 1H NMR (300 MHz, CDCl3): δ =
7.78–7.67 (m, 4 H), 7.33–7.19 (m, 4 H), 6.05 (d, J = 9.2 Hz, 1 H),
3.93 (dd, J = 15.5, 9.3 Hz, 1 H), 3.79–3.70 (m, 1 H), 3.55 (s, 3 H),
3.28 (dd, J = 15.7, 8.6 Hz, 1 H) ppm. 13C NMR (50 MHz, CDCl3):
δ = 171.7, 167.7, 143.5, 138.1, 134.0, 131.9, 129.0, 127.1, 124.6,
124.5, 123.3, 54.4, 51.9, 46.2, 35.0 ppm. HRMS (ESI): calcd. for
C19H15NO4 + Na 344.0899; found 344.0907. The relative configu-
ration of compound 4 was established by NOE analysis.
Methyl (R)-2-[(1,3-Dioxoisoindolin-2-yl)(1-naphthyl)methyl]acrylate
(3p): Rf = 0.4 (petroleum ether/EtOAc = 8:1); 91% yield. [α]2D0
=
52.5 (c = 0.20, CHCl3); 89% ee, determined by HPLC analysis
[Daicel chiralpak AD, n-hexane/iPrOH = 90:10, 1.0 mL/min, λ =
220 nm, t(major) = 27.63, t(minor) = 26.16 min]. 1H NMR
(400 MHz, CDCl3): δ = 8.00–7.81 (m, 5 H), 7.73–7.63 (m, 3 H),
7.55–7.44 (m, 3 H), 7.23 (s, 1 H), 6.59 (d, J = 1.2 Hz, 1 H), 5.63 (d,
J = 1.6 Hz, 1 H), 3.71 (s, 3 H) ppm. 13C NMR (50 MHz, CDCl3): δ
= 168.0, 166.1, 137.1, 134.2, 133.9, 132.1, 131.7, 130.9, 129.4, 129.0,
127.3, 126.9, 126.8, 125.7, 125.1, 123.5, 123.0, 52.3, 51.3 ppm.
HRMS (ESI): calcd. for C23H17NO4 + Na 394.1055; found
394.1008.
Methyl (R)-2-[Phenyl(4,5,6,7-tetrachloro-1,3-dioxoisoindolin-2-yl)-
methyl]acrylate (3q): Rf = 0.3 (petroleum ether/EtOAc = 20:1); 91%
yield. [α]2D0 = 144.6 (c = 0.38, CHCl3); 89% ee, determined by
HPLC analysis [Daicel chiralpak AD, n-hexane/iPrOH = 90:10,
1.0 mL/min, λ = 254 nm, t(major) = 12.17, t(minor) = 10.90 min].
1H NMR (400 MHz, CDCl3): δ = 7.44–7.42 (m, 2 H), 7.39–7.33
(m, 3 H), 6.59 (d, J = 1.6 Hz, 1 H), 6.33 (s, 1 H), 5.62 (d, J =
1.6 Hz, 1 H), 3.73 (s, 1 H) ppm. 13C NMR (50 MHz, CDCl3): δ =
166.0, 163.2, 159.5, 140.3, 136.7, 136.2, 130.6, 128.9, 128.7, 128.5,
Methyl
(R)-5-[(R)-(1,3-Dioxoisoindolin-2-yl)(phenyl)methyl]-3-
phenyl-4,5-dihydroisoxazole-5-carboxylate (5): TEA (43.4 µL,
0.31 mmol) was added to a solution of chlorobenzaldoxime
(48.5 mg, 0.31 mmol) in anhydrous CH2Cl2 (1 mL) at 0 °C. After
stirring for 10 min a solution of 3n (50 mg, 0.16 mmol) in anhy-
drous CH2Cl2 was added dropwise. The mixture was stirred at
room temperature for 36 h. Then the reaction was quenched with
water (5 mL) and the organic layer was separated. The aqueous
layer was extracted with EtOAc (2ϫ5 mL). The combined organic
layers were dried with anhydrous Na2SO4 and concentrated. Flash
chromatography on silica gel (petroleum ether/ethyl acetate = 15:1)
afforded the diastereomerically pure product 5 as a white solid
127.3, 55.6, 52.3 ppm. HRMS (ESI): calcd. for C19H11Cl4NO4
Na 479.9340; found 479.9358.
+
Methyl (S)-2-[(2-Chlorophenyl)(4,5,6,7-tetrachloro-1,3-dioxoisoindo-
lin-2-yl)methyl]acrylate (3r): Rf = 0.3 (petroleum ether/EtOAc =
20:1); 92% yield. [α]2D0 = 69.9 (c = 0.24, CHCl3); 90% ee, deter-
mined by HPLC analysis [Daicel chiralpak AD, n-hexane/iPrOH =
90:10, 1.0 mL/min, λ = 220 nm, t(major) = 10.22, t(minor) =
8.81 min]. 1H NMR (400 MHz, CDCl3): δ = 7.48–7.46 (m, 1 H),
7.42–7.39 (m, 1 H), 7.30–7.27 (m, 2 H), 6.76 (s, 1 H), 6.60 (d, J =
1.2 Hz, 1 H), 5.57 (d, J = 2.0 Hz, 1 H), 3.73 (s, 3 H) ppm. 13C
NMR (50 MHz, CDCl3): δ = 165.6, 163.1, 135.5, 133.7, 130.1,
129.9, 129.8, 129.6, 127.1, 52.7, 52.4 ppm. HRMS (ESI): calcd. for
C19H10Cl5NO4 + Na 513.8950; found 513.8951.
(58.3 mg, 85%). Rf = 0.3 (petroleum ether/EtOAc = 5:1). [α]2D0
=
87.2 (c = 0.86, CHCl3); 82% ee, determined by HPLC analysis
[Daicel chiralcel OD, n-hexane/iPrOH = 70:30, 1.0 mL/min, λ =
254 nm, t(major)
= 8.20, t(minor) =
10.71 min]. 1H NMR
(400 MHz, CDCl3): δ = 7.91–7.86 (m, 2 H), 7.79–7.75 (m, 2 H),
7.58–7.51 (m, 4 H), 7.38–7.22 (m, 6 H), 6.22 (s, 1 H), 4.19 (d, J =
18.4 Hz, 1 H), 3.74 (d, J = 18.4 Hz, 1 H), 3.66 (s, 3 H) ppm. 13C
NMR (50 MHz, CDCl3): δ = 169.9, 167.9, 158.1, 134.5, 134.3,
131.4, 130.3, 128.6, 126.8, 123.7, 91.1, 56.8, 53.2, 41.0 ppm. HRMS
(ESI): calcd. for C26H20N2O5 + H 441.1450; found 441.1450. The
relative configuration of compound 5 was established by NOE
analysis and by analogy to the previous report.[10b]
Methyl (S)-2-[(2-Bromophenyl)(4,5,6,7-tetrachloro-1,3-dioxoisoindo-
lin-2-yl)methyl]acrylate (3s): Rf = 0.3 (petroleum ether/EtOAc =
20:1); 92% yield. [α]2D0 = 63.3 (c = 1.00, CHCl3); 90% ee, deter-
mined by HPLC analysis [Daicel chiralpak AD, n-hexane/iPrOH =
90:10, 1.0 mL/min, λ = 220 nm, t(major) = 11.12, t(minor) =
9.20 min]. 1H NMR (400 MHz, CDCl3): δ = 7.59 (dd, J = 7.8,
1.4 Hz, 1 H), 7.47 (dd, J = 7.8, 1.8 Hz, 1 H), 7.32 (td, J = 7.4,
1.3 Hz, 1 H), 7.21 (td, J = 7.7, 1.5 Hz, 1 H), 6.71 (s, 1 H), 6.61 (d,
J = 1.2 Hz, 1 H), 5.55 (d, J = 1.6 Hz, 1 H) 3.73 (s, 1 H) ppm. 13C
NMR (50 MHz, CDCl3): δ = 165.5, 163.1, 140.5, 135.5, 135.4,
133.3, 130.2, 130.1, 129.7, 127.7, 127.2, 124.0, 55.3, 52.4 ppm.
HRMS (ESI): calcd. for C19H10BrCl4NO4 + Na 557.8445; found
557.8467.
Supporting Information (see also the footnote on the first page of
this article): NMR spectra and HPLC chromatograms of the prod-
ucts 3a–3t, 4 and 5 and crystal data of enantiopure 3e.
Acknowledgments
We are grateful to Sichuan University for financial support.
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(m, 3 H), 6.58 (d, J = 2.0 Hz, 1 H), 6.33 (s, 1 H), 5.61 (d, J =
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Received: August 19, 2009
Published Online: October 5, 2009
Eur. J. Org. Chem. 2009, 5804–5809
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
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