Bis-Lewis acids-catalyzed highly diastereoselective one-pot reductive dehydroxylation of chiral N,O-acetals

Article abstract of DOI:10.1016/j.tet.2009.11.003

A one-pot and highly diastereoselective method for the reductive dehydroxylation of three classes of heterocyclic N,O-acetals with general structure 4 is reported. The method features a 'two in one' concept, namely, by synergetic action of two complementary Lewis acids (BF·OEt₂ and TiCl₄), the bicyclic or tricyclic oxazololactams 5 were formed in situ and reductively cleaved to give the corresponding lactams 6 in a high-yielding and highly diastereoselective manner.

Full text of DOI:10.1016/j.tet.2009.11.003

Tetrahedron 66 (2010) 172–175
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Tetrahedron
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Bis-Lewis acids-catalyzed highly diastereoselective one-pot reductive
dehydroxylation of chiral N,O-acetals
*
Li-Jiao Jiang, Bo Teng, Jian-Feng Zheng, Jian-Liang Ye, Pei-Qiang Huang
Department of Chemistry and Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University,
Xiamen, Fujian 361005, China
a r t i c l e i n f o
a b s t r a c t
Article history:
A one-pot and highly diastereoselective method for the reductive dehydroxylation of three classes of
heterocyclic N,O-acetals with general structure 4 is reported. The method features a ‘two in one’ concept,
namely, by synergetic action of two complementary Lewis acids (BF$OEt2 and TiCl4), the bicyclic or
tricyclic oxazololactams 5 were formed in situ and reductively cleaved to give the corresponding lactams
6 in a high-yielding and highly diastereoselective manner.
Received 3 September 2009
Accepted 3 November 2009
Available online 6 November 2009
Keywords:
Ó 2009 Elsevier Ltd. All rights reserved.
Cooperative effects
Diastereoselectivity
Lewis acids
Asymmetric synthesis
Heterocycles
1. Introduction
In our previous work on the stereoselective synthesis of 3-
alkylindolidin-3-ones13 6-I from N,O-acetals 4-I,11 it was found that
The concept of cooperative Lewis acid/base/transition metal
catalysis and multi-catalyst systems has been developed to achieve
some challenging transformations such as asymmetric synthesis1
and one-pot reactions.2–4 In the context of stereocontrolled syn-
thesis of N-containing heterocycles, Meyers’ chiral bicyclic lactam
(1)-based synthetic methodology is gaining popular.5–8 In this
the stepwise bicyclic oxazololactams (5-I) formation-reductive
ring-opening reaction (Method B, Scheme 2) afforded a better
diastereoselectivity than the direct reductive dehydroxylation of
4-I did (Method A). Similar results were obtained in the synthesis
of methyl 5-alkyltetramate derivatives 6-II.12 The modest diaster-
eoselectivity of method A and the overall inefficiency of the two-step
procedure (Method B) made it worthwhile to develop an improved
method to achieve both high efficiency and high diastereoselectivity.
methodology, the cyclocondensation between
d-oxo acids and en-
antiomeric pure
b
-aminoalcohols5–7 (Scheme 1) has been employed
almost as the sole entry to the chiral bicyclic/tricyclic oxazolo-
lactams (1).8,9 An alternative and more flexible method to access the
chiral bicyclic/tricyclic oxazololactams resides in the Grignard ad-
dition to cyclic imides 2.9a,10 To the best of our knowledge, this
advantageous approach was not pursuit until the works reported
from these laboratories.11,12
R1
R2
R1
R2
Method C
R
RMgX
this work
O
O
O
N
HO
HO
N
series
*
HO
*
Ph
4-I/4-II
I ~ III
Ph
3-I/3-II
for
Method A
Method B
F B OEt
•
3
2
R2 = H
p-TsOH
Et3SiH
R2
R2
O
n
n
HO2C
NH2
ref.8
O
O
N
R1
R2
O
N
O
R1
R2
refs. 5-7
R1
H
R2
for n = 0;
R2 = Me R1
ref. 9a
*
TiCl4
Et3SiH
*
OH
R1
R
*
R
*
R1
O
+
*
*
OH
O
O
1 (n = 0, 1)
N
*
O
N
*
N
*
R
2
H
Meyers' bicyclic lactams
HO
HO
Ph
7-I/7-II
Ph
6-I/6-II
Ph
Scheme 1. Two approaches for the synthesis of chiral non-racemic bicyclic lactams.
5-I/5-II
(I: R1 + R2 = (−CH=)4; II: R1 = OMe, R2 = H)
[ III: R1 + R2 = (CH2)4 for method C]
* Corresponding author. Fax: þ86 592 2186400.
E-mail address: pqhuang@xmu.edu.cn (P.-Q. Huang).
Scheme 2.
0040-4020/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2009.11.003

L.-J. Jiang et al. / Tetrahedron 66 (2010) 172–175
173
With this aim in mind, we set to explore a bis-Lewis acids-catalyzed
one-pot cyclization-reductive ring-opening reaction variant on
three ring systems I–III (Scheme 2, Method C), and the results are
reported herein.
alkylisoindolin-1-one derivatives (4-I) led us to consider an ex-
tension of this concept to the tetramate series 4-II.11 5-Alkylte-
tramates and 5-alkyltetramic acids are frameworks found in
a number of bioactive natural products.16,17 Treatment of the N,O-
acetal 4-IIa12 with 1.0 molar equiv of BF3$OEt2 at ꢀ78 ꢁC for 2 h,
followed by TiCl4-mediated reduction with triethylsilane led to 5-
methyltetramate 6-IIa in a 91:9 diastereoselectivity and 88% com-
bined yield (Table 2, entry 1). Extension of this method to other
N,O-acetals 4-IIb–g yielded the corresponding 5-alkyltetramates 6-
IIb–g and the results are displayed in Table 2. As can be seen from
Table 2, comparing with method B, the one-pot reaction (Method
C) gave, in all cases, significantly improved chemical yields while
remaining about the same diastereoselectivities.
2. Results and discussion
Our basic consideration was to take advantages of both the
brevity of method A and the high diastereoselectivity offered by
method B, and develop an efficient and highly diastereoselective
one-pot reductive dehydroxylation method. In view of the excellent
capacity of boron trifluoride etherate in the dehydroxylation,10c,f,11
and that of titanium tetrachloride in the cleavage of oxazolidine
rings,11 they were selected as complementary Lewis acids4 for the
one-pot reductive dehydroxylation of three classes of heterocyclic
N,O-acetals 4.
Table 2
Comparison of the two methods for the synthesis of methyl 5-alkyltetramates 6-II
from N,O-acetals 4-II
The synthesis of the series of 3-alkylindolin-1-one derivatives13
6-I was first investigated (Scheme 3). Thus the known N,O-acetal 4-
Ia11 was treated with 1.0 molar equiv of BF3$OEt2 at ꢀ78 ꢁC, and
stirred for 2 h, which was followed by successive addition of TiCl4
and triethylsilane.14 From this one-pot reaction, 3-methylisoindolin-
1-ones 6-Ia and 7-Ia were obtained in 94:6 diastereoselectivity with
96% combined yield (Table 1, entry 1). The reaction was presumed to
proceed via the N-acyliminium intermediate A.15 The one-pot re-
action of other N,O-acetals 4-Ib–e11 afforded the corresponding (S)-
3-alkylisoindolin-1-ones 6-Ib–e11 with similar high efficiency and
excellent diastereoselectivities (Table 1, entries 2–5).
MeO
R
MeO
R
1) BF3•OEt2, −78 °C, 2 h
2) TiCl4, Et3SiH, CH2Cl2
O
O
N
N
HO
HO
H
+ 7-II
(α-R)
−78 °C-rt, 48 h
Method C
HO
Ph
Ph
4-II
6-II
Entry
Starting
compound (R)
Method B12 6-II:7-II
Method C 6-II:7-II
(% overall yield)a
(% yield)a
1
2
3
4
5
6
7
4-IIa (Me)
4-IIb (Et)
4-IIc (n-C5H11
91:9 (71)
91:9 (65)
93:7 (66)
92:8 (69)
88:12 (60)
99:1 (66)
88:12 (41)
91:9 (88)b
91:9 (95)c
92:8 (85)b
90:10 (83)b
90:10 (93)b
96:4 (72)c
90:10 (56)b
)
)
)
4-IId (n-C6H13
4-IIe (n-C7H15
4-IIf (i-Bu)
4-IIg (Bn)
1) BF3•OEt2, −78 °C, 2 h
2) TiCl4, Et3SiH, CH2Cl2
(α-R)
R
R
7-I
+
O
O
N
N
HO
HO
H
−78 °C-rt, 48 h
Method C
a
Isolated yield.
HO
b
c
Ratio determined by 1H NMR.
Ratio determined by column chromatographic separation.
Ph
Ph
4-I
6-I
F B OEt
•
Et3SiH
3
2
To probe the intermediate of the reaction, the N,O-acetal 4-IIa
was treated with 1.0 molar equiv of BF3$OEt2 at ꢀ78 ꢁC for 2 h. The
isolated product turned out to be the bicyclic oxazololactam 5-IIa.
The stereochemistry of 5-IIa was determined to be (R,S) by NOESY
experiments.12
The method was further extended to another ring system. Thus,
the one-pot cyclization–reduction of the N,O-acetals 4-IIIa8c,18 and
4-IIIb, derived from (R)-imide 3-III18 by Grignard addition, afforded
the diastereomeric lactams 6-IIIa and 6-IIIb in 95:5 and 90:10 ratio,
respectively (Scheme 4).
TiCl4
R
O
*
O
O
R
N
N
*
ClnTiO
Ph
A-I
Ph
5-I
Scheme 3.
Table 1
Comparison of method B and method C for the synthesis of 3-substituted iso-
indolin-1-ones 6-I from N,O-acetals 4-I
O
O
Ph
Ph
RMgX, CH2Cl2
Method B11b 6-I:7-Ia
Method C 6-I:7-Ia
N
Entry
Starting
compound (R)
N
(% overall yield)b
(% yield)c
−15 °C, 2 h
HO
HO
R
HO
O
1
2
3
4
5
4-Ia (Me)
4-Ib (i-Bu)
4-Ic (n-C7H15
4-Id (Ph)
4-Ie (Bn)
95:5 (83)
100:0 (33)
91:9 (60)
96:4 (75)
92:8 (39)
94:6 (96)
97:3 (91)
93:7 (83)
95:5 (96)
90:10 (75)
MeMgI, yield: 85%
4-IIIa (R = Me)
3-III
n-C5H11MgBr, yield: 81% 4-IIIb (R = n-C5H11
)
)
O
1) BF3•OEt2, −78 °C, 2 h
Ph
a
N
+ 7-IIIa,b
(β-R)
Ratio determined by column chromatographic separation.
Overall yield from 4-I.
Isolated yield.
2) TiCl4, Et3SiH, CH2Cl2
b
c
−78 °C - rt, 48 h
HO
R
92%
89%
6-IIIa (ds = 95:5)
6-IIIb (ds =90:10)
It is worth notice that the low overall yields (33%; 39%) in the
Scheme 4.
synthesis of 3-iso-butyl and benzyl (3S)-isoindolin-1-one de-
rivatives 6-Ib,e by method B (Table 1, col. 3, entries 2, 5)11 were
greatly improved (91%; 75%), which indicated that the reaction
conditions used in method C are quite mild, and the dehydration
side reaction was efficiently avoided.
The oily property of both diastereomers 6-IIIa and 6-IIIb pre-
vented a determination of the stereochemistry of the newly formed
chiral center by single crystal X-ray diffraction analysis, which was
deduced as follows. The lactams 6-IIIa and 6-IIIb were presumed to
be formed via the corresponding cyclic intermediates 5-IIIa/b.
The success in the bis-Lewis acids-mediated highly diastereo-
selective one-pot reductive dehydroxylation of (S)-3-hydroxy-3-

174
L.-J. Jiang et al. / Tetrahedron 66 (2010) 172–175
20
Indeed when N,O-acetal 4-IIIa was treated with BF3$OEt2, tricyclic
lactam 5-IIIa was formed in 70% yield as a sole diastereomer. The
NOESY experiments showed that the methyl and phenyl groups are
in the same face (Fig. 1). In light of the well documented fact that
the reductive ring-opening reaction of the similar cyclic lactams
with Lewis acid/Et3SiH system generally undergoes with retention
of configuration,5–9,11 the C-3 stereochemistry of 6-IIIa and 6-IIIb
was assigned as R.
149–150.5 ꢁC (EtOAc/PE); [
a
]
þ67.3 (c 1.00, CHCl3) {lit.11b mp 134–
D
20
135 ꢁC; [
a
]
D
ꢀ56.6 (c 1.07, CHCl3) for the antipode}.
4.1.5. (3S,10S)-3-Benzyl-2-(2-hydroxyl-1-phenylethyl)isoindolin-1-
one (3S,10S)-6-Ie. dr¼90:10, combined yield 75%. White solid, mp
20
149–150.5 ꢁC (EtOAc/PE); [
a
]
þ67.3 (c 1.0, CHCl3) {lit.11b mp 134–
D
20
135 ꢁC}; [
a
]
ꢀ56.6 (c 1.07, CHCl3) for the antipode}.
D
4.2. (5S,10S)-2-Hydroxyl-1-phenylethyl-4-methoxy-5-alkyl-
1H-pyrrol-2(5H)-ones
O
5.06
H
N
(5S,10S)-6-IIa–g were prepared according to the general pro-
cedure. The yields and diastereomeric ratios are indicated in Table
2, and the physical and spectroscopic data are in agreement with
those reported in Ref. 12.
Ph
4.H29
1.48Me
O
4.67
H
Figure 1. The observed NOEs for 5-IIIa (in part).
4.2.1. 3-Methyl-2-[(10R)-10-phenyl-20-hydroxyethyl]-hexahy-
3. Conclusion
droisoindolin-1-one (6-IIIa). dr¼95:5, combined yield 92%. Major
20
diastereomer (6-IIIa): colorless oil. [
a
]
þ45.7 (c 3.3, CHCl3). IR
D
In summary, by the synergetic action of two different Lewis
acids we were able to achieve both the efficiency and high dia-
stereoselectivity in the one-pot transformation of three classes of
N,O-acetals (4-I–III) into the corresponding lactams (6-I–III). Thus,
in combination with our previous results,11,12 a versatile two-step
entrance to three classes of cyclic lactams (6-I–III) from imide 3-I–
III was established. The lactams obtained are useful synthetic in-
termediates for N-containing bioactive compounds and natural
products, and may serve as valuable chiral ligands. It was believed
that the ‘two in one’ concept will find application in organic
synthesis.
(film): 3357, 2921, 2847, 1640, 1424, 1347, 1253, 1205, 1088 cmꢀ1. 1H
NMR (400 MHz, CDCl3)
d
1.19 (d, J¼6.87 Hz, 3H, CH3), 1.62–1.82 (m,
4H), 2.04–2.27 (m, 4H), 3.66 (m, 1H), 4.01 (ddd, J¼12.32, 6.65,
3.26 Hz, 1H), 4.31 (td, J¼12.34, 7.71 Hz, 1H), 4.61 (dd, J¼7.69,
3.20 Hz, 1H), 5.20 (dd, J¼7.37, 3.82 Hz, 1H), 7.25–7.40 (m, 5H, Ar-H)
ppm; 13C NMR (100 MHz, CDCl3)
d 16.1, 20.0, 21.8, 22.0, 22.9, 59.2,
61.9, 64.8, 127.1, 127.7, 128.7, 130.8, 138.6, 156.1, 172.6 ppm; MS (ESI,
m/z): 272 (MþHþ, 100). Anal. Calcd for C17H21NO2: C, 75.25; H, 7.80;
N, 5.16. Found: C, 75.04; H, 7.48; N, 4.81.
4.2.2. 3-Ethyl-2-[(10R)-10-phenyl-20-hydroxyethyl]-hexahy-
droisoindolin-1-one (6-IIIb). dr¼90:10, combined yield 89%. Major
20
4. Experimental section
diastereomer (6-IIIb): colorless oil. [
a
]
ꢀ63.5 (c 0.3, CHCl3). IR
D
(film): 3377, 2925, 2853, 1656, 1420, 1068 cmꢀ1. 1H NMR (400 MHz,
CDCl3)
4.1. General procedure for the one-pot cyclization-reductive
ring-opening of compounds 4
d
0.87 (t, J¼7.01 Hz, 3H), 0.87(m, 1H), 1.09 (m, 1H), 1.15–1.24
(m, 4H), 1.56 (m, 1H), 1.66–1.80 (m, 5H), 2.10 (m, 2H), 2.18–2.34 (m,
2H), 3.73 (dd, J¼4.62, 2.16 Hz, 1H), 4.01 (ddd, J¼12.34, 6.71, 3.21 Hz,
1H), 4.30 (td, J¼12.34, 7.70 Hz, 1H), 4.49 (dd, J¼7.64, 3.22 Hz, 1H),
5.24 (dd, J¼7.73, 6.75 Hz, 1H), 7.17–7.36 (m, 5H) ppm; 13C NMR
To a cooled (ꢀ78 ꢁC) dichloromethane (9 mL) solution of a di-
astereomeric mixture of N,O-acetal (0.324 mmol) 4 was added
dropwise boron trifluoride etherate (0.324 mmol) under nitrogen
atmosphere. After stirring at ꢀ78 ꢁC for 2 h, TiCl4 (0.486 mmol) and
triethylsilane (3.24 mmol) were added successively. After stirring at
ꢀ78 ꢁC for an additional 2 h, the mixture was allowed to warm up
and was stirred for about 48 h. The reaction was quenched with
a saturated NaHCO3 solution. The organic layer was separated and
the aqueous phase was extracted with CH2Cl2 (3ꢂ15 mL). The
combined organic layers were washed with brine, dried over an-
hydrous Na2SO4, filtered, and concentrated under reduced pres-
sure. The residue was purified by flash chromatography eluting
with (EtOAc/PE, v/v) to give lactam 6 and its diastereomer 7.
(100 MHz, CDCl3)
d 14.0, 20.1, 20.9, 21.9, 22.1, 22.5, 23.3, 27.7, 31.7,
62.2, 62.7, 64.8, 127.1, 127.7, 128.7, 132.1, 138.7, 154.3, 173.3 ppm; MS
(ESI, m/z): 328 (MþHþ, 100). HRESIMS Calcd for [C21H27NO3þH]þ:
328.2277; found: 328.2288.
Acknowledgements
The authors are grateful to the NSFC (20832005, 20602028), and
the program for Innovative Research Team in Science & Technology
(University) in Fujian Province for financial support.
References and notes
4.1.1. (3S,10S)-2-(2-Hydroxyl-1-phenylethyl)-3-methylisoindolin-1-
20
one (3S,10S)-6-Ia. dr¼94:6, combined yield 96%. Colorless oil. [
a]
D
1. For selected reviews on bifunctional/cooperative asymmetric catalysis, see: (a)
Shibasaki, M.; Yoshikawa, N. Chem. Rev. 2002, 102, 2187–2209; (b) Kanai, M.;
Kato, N.; Ichikawa, E.; Shibasaki, M. Synlett 2005, 1491–1508; (c) Yamamoto, H.;
Futatsug, K. Angew. Chem., Int. Ed. 2005, 44, 1924–1942; (d) Paull, D. H.; Abra-
ham, C. J.; Scerba, M. T.; Alden-Danforth, E.; Lectka, T. Acc. Chem. Res. 2008, 41,
655–663.
2. For selected reviews on multicomponent reactions and one-pot reactions, see:
(a) Multicomponent Reactions; Zhu, J.-P., Bienayme, H., Eds.; Wiley-VCH:
Weinheim, 2005; (b) Bunce, R. A. Tetrahedron 1995, 51, 13103–13159; (c) Bi-
20
ꢀ88.2 (c 1.3, CHCl3) {lit.11b
[
a]
þ87.9 (c 0.99, CHCl3) for the
D
antipode}.
4.1.2. (3S,10S)-2-(2-Hydroxyl-1-phenylethyl)-3-isobutylisoindolin-1-
one (3S,10S)-6-Ib. dr¼97:3, combined yield 91%. White solid, mp
´
20
54.5–56.5 ꢁC (EtOAc/PE); [
a
]
ꢀ53.1 (c 1.04, CHCl3) {lit.11b mp 54–
D
20
56 ꢁC; [
a
]
þ44.7 (c 0.95, CHCl3) for the antipode}.
D
´
enayme, H.; Hulme, C.; Oddon, G.; Schmitt, P. Chem.dEur. J. 2000, 6, 3321–
3329; (d) Nicolaou, K. C.; Edmonds, D. J.; Bulger, P. G. Angew. Chem., Int. Ed.
2006, 45, 7134–7186; (e) Do¨mling, A. Chem. Rev. 2006, 106, 17–89; (f) Ganem, B.
Acc. Chem. Res. 2009, 42, 463–472.
4.1.3. (3S,10S)-3-n-Heptyl-2-(2-hydroxyl-1-phenylethyl) isoindolin-
1-one (3S,10S)-6-Ic. dr¼93:7, combined yield 83%. Colorless oil.
3. For selected reviews on cooperative Lewis acid/base/transition metals systems
and multi-catalyst systems for one-pot organic transformations, see: (a) Lee, J.
M.; Na, Y.; Han, H.; Chang, S. Chem. Soc. Rev. 2004, 33, 302–312; (b) Wang, C. Y.;
Xi, Z. F. Chem. Soc. Rev. 2007, 36, 1395–1406; (c) Park, Y. J.; Park, J.-W.; Jun, C.-H.
Acc. Chem. Res. 2008, 41, 222–234; (d) Shao, Z. H.; Zhang, H.-B. Chem. Soc. Rev.
2009, 38, 2745–2755.
20
20
[
a]
ꢀ41.0 (c 0.95, CHCl3) {lit.11b
[
a]
þ41.1 (c 0.68, CHCl3)}.
D
D
4.1.4. (3S,10S)-2-(2-Hydroxyl-1-phenylethyl)-3-phenylisoindolin-1-
one (3S,10S)-6-Id. dr¼95:5, combined yield 96%. White solid, mp

L.-J. Jiang et al. / Tetrahedron 66 (2010) 172–175
175
4. For reviews on the use of Lewis acids in organic synthesis, see: (a) Acid Catalysis in
Modern Organic Synthesis; Yamamoto, H., Ishihara, K., Eds.; Wiley-VCH: Weinheim,
2008; Vols.1 and 2;Forexamples ofsynergisticcombinationofLewis acids, see:(b)
Nicolaou, K. C.; Hwang, C. K.; Duggan, M. E. J. Am. Chem. Soc.1989, 111, 6682–6690;
(c) Hong, C. Y.; Kishi, Y. J. Am. Chem. Soc.1991,113, 9693–9694; (d) Myers, E. L.; Butts,
C. P.; Aggarwal, V. K. Chem. Commun. 2006, 4434–4436; (e) Myers, E. L.; de Vries, J.
G.; Aggarwal, V. K. Angew. Chem., Int. Ed. 2007, 46, 1893–1896.
5. For reviews on the chemistry of chiral bicyclic lactams, see: (a) Romo, D.;
Meyers, A. I. Tetrahedron 1991, 47, 9503–9569; (b) Meyers, A. I.; Brengel, G. P.
Chem. Commun. 1997, 1–8; (c) Groaning, M. D.; Meyers, A. I. Tetrahedron 2000,
56, 9843–9873; (d) Escolano, C.; Amat, M.; Bosch, J. Chem.dEur. J. 2006, 12,
8198–8207; (e) Bouet, A.; Oudeyer, S.; Dupas, G.; Marsais, F.; Levacher, V. Tet-
rahedron: Asymmetry 2008, 19, 2396–2401.
6. For selected examples, see: (a) Burgess, L. E.; Meyers, A. I. J. Am. Chem. Soc. 1991,
113, 9858–9859; (b) Meyers, A. I.; Burgess, L. E. J. Org. Chem. 1991, 56, 2294–
2296; (c) Burgess, L. E.; Meyers, A. I. J. Org. Chem. 1992, 57, 1656–1662; (d)
Freville, S.; Ce´le´rier, J. P.; Thuy, V. M.; Lhommet, G. Tetrahedron: Asymmetry
1995, 6, 2651–2654; (e) Jossang, A.; Melhaoui, A.; Bodo, B. Heterocycles 1996,
43, 755–766; (f) Yamazaki, N.; Ito, T.; Kibayashi, C. Tetrahedron Lett. 1999, 40,
739–742; (g) Meyers, A. I.; Andres, C. J.; Resek, J. E.; Woodall, C. C.; McLaughlin,
M. A.; Lee, P. H.; Price, D. A. Tetrahedron 1999, 55, 8931–8952; (h) Jiang, J. L.;
DeVita, R. J.; Doss, G. A.; Goulet, M. T.; Wyvratt, M. J. J. Am. Chem. Soc. 1999, 121,
593–594.
Pattenden, G. J. Chem. Soc., Perkin Trans. 1 1993, 2567–2579; (e) Kato, Y.;
Takemoto, M.; Achiwa, K. Chem. Pharm. Bull. 1993, 41, 2003–2006; (f) Huang,
P.-Q.; Wang, S.-L.; Ye, J.-L.; Ruan, Y.-P.; Huang, Y.-Q.; Zheng, H.; Gao, J. X. Tet-
rahedron 1998, 54, 12547–12560; (g) Kim, G.; Lee, E. Tetrahedron: Asymmetry
2001, 12, 2073–2076; (h) Lebrun, S.; Couture, A.; Deniau, E.; Grandclaudon, P.
Tetrahedron: Asymmetry 2003, 14, 2625–2632; (i) Bailey, P. D.; Morgan, K. M.;
Smith, D. I.; Vernon, J. M. Tetrahedron 2003, 59, 3369–3378; (j) Bahajaj, A. A.;
Moore, M. H.; Vernon, J. M. Tetrahedron 2004, 60, 1235–1246; (k) Kossenjans,
M.; Soeberdt, M.; Wallbaum, S.; Harms, K.; Martens, J.; Aurich, H. G. J. Chem. Soc.,
Perkin Trans. 1 1999, 2353–2365; (l) Garcia, E.; Arrasate, S.; Ardeo, A.; Lete, E.;
Sotomayor, N. Tetrahedron Lett. 2001, 42, 1511–1513.
11. (a) Chen, M.-D.; Zhou, X.; He, M.-Z.; Ruan, Y.-P.; Huang, P.-Q. Tetrahedron 2004,
60, 1651–1657; (b) Chen, M.-D.; He, M.-Z.; Zhou, X.; Huang, L.-Q.; Ruan, Y.-P.;
Huang, P.-Q. Tetrahedron 2005, 61, 1335–1344.
12. Jiang, L.-J.; Lan, H.-Q.; Zheng, J.-F.; Ye, J.-L.; Huang, P.-Q. Synlett 2009, 297–301.
13. For other methods, see: (a) Allin, S. M.; Northfield, C. J.; Page, M. I.; Slawin, A.
M. Z. J. Chem. Soc., Perkin Trans. 1 2000, 1715–1721; (b) Pe´rard-Viret, J.; Prange´,
T.; Tomas, A.; Royer, J. Tetrahedron 2002, 58, 5103–5108; (c) Deniau, E.; Enders,
D.; Couture, A.; Grandclaudon, P. Tetrahedron: Asymmetry 2003, 14, 2253–2258;
(d) Comins, D. L.; Hiebel, A.-C. Tetrahedron Lett. 2005, 46, 5639–5642; (e) Sun,
X.-W.; Liu, M.; Xu, M.-H.; Lin, G.-Q. Org. Lett. 2008, 10, 1259–1262; (f) Deniau, E.;
Couture, A.; Grandclaudon, P. Tetrahedron: Asymmetry 2008, 19, 2735–2740 and
references cited therein.
7. For recent examples, see: (a) Itoh, T.; Yamazaki, N.; Kibayashi, C. Org. Lett. 2002,
4, 2469–2472; (b) Penhoat, M.; Levacher, V.; Dupas, G. J. Org. Chem. 2003, 68,
9517–9520; (c) Bouet, A.; Heller, B.; Papamicae¨l, C.; Dupas, G.; Oudeyer, S.;
Marsais, F.; Levacher, V. Org. Biomol. Chem. 2007, 5, 1397–1404; (d) Edwards, D.
J.; House, D.; Sheldrake, H. M.; Stone, S. J.; Wallace, T. W. Org. Biomol. Chem.
2007, 5, 2658–2669; (e) Resek, J. E. J. Org. Chem. 2008, 73, 9792–9794; (f) Pira,
S. L.; Wallace, T. W.; Graham, J. P. Org. Lett. 2009, 11, 1663–1666; (g) Amat, M.;
Fabregat, R.; Griera, R.; Bosch, J. J. Org. Chem. 2009, 74, 1794–1797 and refer-
ences cited therein; (h) Husain, S. M.; Fro¨hlich, R.; Schepmann, D.; Wu¨nsch, B. J.
Org. Chem. 2009, 74, 2788–2793.
8. For methods involving cyclic imides, see: (a) Yamazaki, N.; Ito, T.; Kibayashi, C.
Org. Lett. 2000, 2, 465–467; (b) Yamazaki, N.; Dokoshi, W.; Kibayashi, C. Org.
Lett. 2001, 3, 193–196; for related works, see: (c) Mukaiyama, T.; Yamashita, H.;
Asami, M. Chem. Lett. 1983, 385–388; (d) Teran, J. L.; Gnecco, D.; Galindo, A.;
Juarez, J.; Bernes, S.; Enriquez, R. G. Tetrahedron: Asymmetry 2001, 12, 357–360.
9. (a) Meyers, A. I.; Lefker, B. A.; Sowin, T. J.; Westrum, L. J. J. Org. Chem. 1989, 54,
4243–4246; (b) Penhoat, M.; Leleu, S.; Dupas, G.; Papamicaes, C.; Marsais, F.;
Levacher, V. Tetrahedron Lett. 2005, 46, 8385–8389.
14. For reviews, see: (a) Kursanov, D. N.; Parnes, Z. N.; Loim, N. M. Synthesis 1974,
633–651; (b) Nagai, Y. Org. Prep. Proced. Int. 1980, 12, 13–48.
15. For recent reviews, see: (a) Speckamp, W. N.; Moolenaar, M. J. Tetrahedron
2000, 56, 3817–3856; (b) Maryanoff, B. E.; Zhang, H.-C.; Cohen, J. H.; Turchi, I. J.;
Maryanoff, C. A. Chem. Rev. 2004, 104, 1431–1628; (c) Royer, J. Chem. Rev. 2004,
104, 2311–2352; (d) Yazici, A.; Pyne, S. G. Synthesis 2009, 339–368; (e) Yazici,
A.; Pyne, S. G. Synthesis 2009, 513–541.
16. For reviews, see: (a) Royles, B. J. L. Chem. Rev. 1995, 95, 1981–2001; (b) Henning,
H.-G.; Gelbin, A. Advances in Heterocyclic Chemistry; Academic Press: San Diego,
CA, 1993; Vol. 57, pp 139–185; (c) Ghisalberti, E. L. Studies in Natural Products
Chemistry, Part 9; Elsevier: 2003; Vol. 28, pp 109–163; (d) Schobert, R.; Schlenk,
A. Bioorg. Med. Chem. 2008, 16, 4203–4221.
17. For selected methods for the synthesis of optically active tetramic acids and
tetramates, see: (a) Fustero, S.; Torre, M. G.; Sanz-Cervera, J. F.; Arellano, C. R.;
Piera, J.; Simon, A. Org. Lett. 2002, 4, 3651–3654; (b) Detsi, A.; Afantitis, A.;
Athanasellis, G.; Markopoulos, J.; Igglessi-Markopoulou, O.; Skylaris, C.-K. Eur. J.
Org. Chem. 2003, 4593–4600; (c) Jones, R. C. F.; Pillainayagam, T. A. Synlett 2004,
2815–2817; (d) Schobert, R.; Jagusch, C. Tetrahedron 2005, 61, 2301–2307; (e)
Schobert, R.; Dietrich, M.; Mullen, G.; Urbina-Gonzalez, J.-M. Synthesis 2006,
3902–3914; (f) Farran, D.; Parrot, I.; Martinez, J.; Dewynter, G. Angew. Chem., Int.
Ed. 2007, 46, 7488–7490 and references cited therein.
10. For selected examples on the Grignard addition to imides, see: (a) Evans, D. A.;
Thomas, E. W.; Cherpeck, R. E. J. Am. Chem. Soc. 1982, 104, 3695–3700; (b) Inoue,
Y.; Tazawa, N.; Watanabe, A.; Aoki, Y.; Kakisawa, H. Bull. Chem. Soc. Jpn. 1992, 65,
2866–2868; (c) Yoda, H.; Kitayama, H.; Yamada, W.; Katagiri, T.; Takabe, K.
Tetrahedron: Asymmetry 1993, 4, 1451–1454; (d) James, G. D.; Mills, S. D.;
18. Huang, P.-Q.; Lan, H.-Q.; Chen, M.-D.; Zhang, H.-K. Chin. J. Org. Chem. 2000, 20,
790–794 (in Chinese).