A simple and practical access to enantiopure 2,3-diamino acid derivatives

Article abstract of DOI:10.1016/S0957-4166(99)00052-X

Enantiomerically pure (4R,5R)- and (4S,5S)-2-imidazolines 5 were conveniently obtained on a gram scale. These can be converted into enantiopure (2R,3R)-2,3-diamino ester 6 or 2,3-diamino alcohol 7 by hydrolysis or reduction.

Full text of DOI:10.1016/S0957-4166(99)00052-X

TETRAHEDRON:
ASYMMETRY
Pergamon
Tetrahedron: Asymmetry 10 (1999) 855–862
A simple and practical access to enantiopure 2,3-diamino acid
derivatives
Xiao-Ti Zhou, Ying-Rui Lin ∗ and Li-Xin Dai
Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences,
354 Fenglin Lu, Shanghai 200032, People’s Republic of China
Received 21 December 1998; accepted 29 January 1999
Abstract
Enantiomerically pure (4R,5R)- and (4S,5S)-2-imidazolines5 were conveniently obtained on a gram scale. These
can be converted into enantiopure (2R,3R)-2,3-diaminoester 6 or 2,3-diamino alcohol 7 by hydrolysis or reduction.
© 1999 Elsevier Science Ltd. All rights reserved.
1. Introduction
Recently, much interest has been focused on the synthesis of unnatural and unusual 2,3-diamino acids,
since this class of compound has an intrinsic biological activity. For example, 2,3-diaminopropanoic
acid is an important structural element of some peptide antibiotics, antifungal dipeptides, and other
biologically active compounds.1 (2S,3S)- and (2R,3S)-2,3-Diaminobutanoic acid are present in peptide
antibiotics such as aspartocin, glumamycin, lavendomytin, etc.2 2,3-Diamino-4-phenylbutanoic acid is
a part of aminodeoxybestatin.3 When an unusual 2,3-diamino acid is incorporated into medicinally-
important peptides, it is also expected to modify biological activity in a useful way. Accordingly, the
development of a simple and efficient method to produce enantiomerically pure 2,3-diamino acid from
readily available starting materials is an important goal.
A number of efficient syntheses of chiral 2,3-diamino acids originated from natural optically-active α-
amino acids or from stoichiometrical amounts of chiral reagents. Preparations of 2,3-diaminopropanoic
and 2,3-diaminobutanoic acids have been reported from aspartic acid,4 L-serine5 and threonine.6
Rapoport recently provided a method for the synthesis of 4-phenyl-2,3-diaminobutanoic acid by the
electrophilic substitution at C-3 of an aspartic acid derivative.4 A complementary route to 3-substituted
2,3-diamino acids is the diastereoselective addition of Grignard reagents to α-amino nitrones derived
from L-serine.5 In addition, the stereoselective synthesis of 2,3-diaminobutanoic acid from tert-butyl
∗
Corresponding author. E-mail: linyr@pub.sioc.ac.cn
0957-4166/99/$ - see front matter © 1999 Elsevier Science Ltd. All rights reserved.
PII: S0957-4166(99)00052-X

856
X.-T. Zhou et al. / Tetrahedron: Asymmetry 10 (1999) 855–862
crotonate as the starting material using Sharpless asymmetric aminohydroxylation reaction has been
reported in a 42% overall yield.7 The cycloaddition reaction from (5S)-phenylmorpholin-2-one with aro-
matic imine may afford enantiomerically pure threo-(2S,3R)-3-aryl-2,3-dimino acids in a 36–46% yield.8
Also, an aminated side chain precursor of the anticancer drug taxol was prepared through the β-lactam
synthon method in a 21% yield.9 It is noteworthy that the first catalytic asymmetric hydrogenation of
(E)-α, β-bis-(N-acylamino)acrylates was reported to provide the corresponding optically active (2S,3R)-
2,3-bis-(N-acylamino)carboxylates with 79–82% ee promoted by a rhodium complex bearing the chiral
diphosphine ligand TRAP.10
All of these methods are either low-yielding or lengthy in terms of steps. Thus, a simple and efficient
route to enantiopure 2,3-diamino acids is still of current interest to synthetic organic chemists. Hayashi
and Ito et al. have reported an elegant asymmetric synthesis using gold(I) complex catalyzed aldol
reaction of aldehydes with isocyanoacetates in the presence of chiral ferrocenylphosphine ligands in
1986.11 Recently, they developed a similar stereoselective aldol-type reaction of N-sulfonylimines with
methyl isocyanoacetate catalyzed by gold(I) complexes, which would provide an efficient route to
erythro-2,3-diamino acids.12 As a part of our research into the asymmetric synthesis of 2-imidazoline,13
we have been interested in the synthesis of enantiomerically pure 2,3-diamino acids. Here, we wish to
furnish a simple and efficient access to enantiomerically pure 2,3-diamino acid derivatives started from a
catalytic asymmetric reaction of N-sulfonylimine with isocyanoacetate.
2. Results and discussion
Optically active (4R,5R)- or (4S,5S)-2-imidazolines were synthesized in high yield with 46–88% ee
values in the presence of catalytic amount of Au(I) complex bearing chiral ferrocenylphosphine.13 We
found that the enantiomerically pure 2-imidazoline with 99% ee can be obtained after a common workup
and a single recrystallization in moderate yield. Moreover, catalytic reactions and upgradings can be
performed on a gram scale. This provides a practical synthetically-useful method for the preparation of
enantiomerically pure 2-imidazoline, an important intermediate in organic synthesis. Enantiomerically
pure 2,3-diamino esters were further obtained from enantiomerically pure 2-imidazoline by treatment
with conc. HCl in EtOH (Scheme 1). The results are shown in Table 1.
Scheme 1.

X.-T. Zhou et al. / Tetrahedron: Asymmetry 10 (1999) 855–862
857
Table 1
Synthesis of enantiomerically pure 2,3-diamino acid derivatives from 2-imidazolines
The yield of 2,3-diamino esters obtained was based on the starting material N-sulfonylimines including
the following procedures: a catalytic enantioselective reaction of N-sulfonylimine 1 and isocyanoacetate
2; purification of cis-2-imidazoline 5, recrystallization of enantiomerically pure cis-2-imidazoline, and
hydrolysis of optically pure cis-2-imidazoline. When (R,S)-ferrocenylphosphine (R,S)-4 was used as
a chiral ligand for the catalytic reaction, (2R,3R)-2,3-diamino esters (2R,3R)-6 was obtained. On the
contrary, (2S,3S)-diamino esters (2S,3S)-6 was also obtained easily by using (S,R)-ferrocenylphosphine
ligand (S,R)-4 (entries 3 and 5).
2,3-Diamino-3-phenylpropanoic acid has been revealed as an alternative to the side chain of taxol for
improving the water solubility of that anticancer drug.9 Removal of the tosyl group from our product,
2,3-diamino ester, was crucial for the synthesis of free 2,3-diamino acids. We found that the tosyl group
in 2,3-diamino ester can be easily removed by treatment with phenol in a refluxing solution of 33%
HBr/AcOH, followed by addition of water and neutralization with propylene oxide to afford free (2R,3R)-
2,3-diamino acid in 71% yield (Scheme 2).14
Scheme 2.
It is well known that chiral amino alcohols are important building blocks for the synthesis of
biologically-active molecules and have been extensively used in the asymmetrical reactions as a chiral au-
xiliary or ligand.15 The asymmetric synthesis of 1,2-amino alcohols has been extensively reported.15a,16
However, there have been few reports of asymmetric synthesis to 2,3-diamino alcohols, which may
become precursors of new kinds of amino alcohol compounds. Using enantiomerically pure 2,3-diamino
esters obtained using our procedure, chiral 2,3-dimino alcohols can be readily obtained by the reduction
with LiAlH4/THF at refluxing conditions in high yield as shown in Scheme 1.

858
X.-T. Zhou et al. / Tetrahedron: Asymmetry 10 (1999) 855–862
In conclusion, we have provided a simple and practical route to 3-aryl-substituted enantiopure 2,3-
diamino acid derivatives in good yield, which was started from a catalytic asymmetric reaction of readily
available N-sulfonylimine and isocyanoacetate.
3. Experimental
A typical procedure for the preparation of cis-imidazoline 5c: a mixture of Me2SAuCl17 (3, 9.97 mg,
0.034 mmol) and (R,S)-chiral ferrocenylphosphine18 (4, 20.8 mg, 0.028 mmol) in CH2Cl2 (25 mL) was
stirred for 15 min under nitrogen. To the solution, 1.95 g (5.77 mmol) of 1b19and 0.66 g (5.87 mmol) of
ethyl isocyanoacetate20 2, were added. The mixture was stirred under nitrogen at 25°C for 20 h. After
removal of the catalyst by filtration, the solvent was evaporated under vacuum to give a crude cis:trans
(90:10) mixtures of 2-imidazoline. The cis isomer was isolated by column chromatography over silica
gel eluting with petroleum ether:ethyl acetate:dichloromethane (4:2:1) to give 74% ee of cis-(4R,5R)-2-
imidazoline in 78% yield. The optically pure cis-5c was obtained with 99% ee from the filtrate by the
recrystallization in THF:n-hexane (16.5 mL:33 mL).
3.1. (4R,5R)-cis-4-(Ethoxylcarbonyl)-5-phenyl-1-N-tosyl-2-imidazoline 5a
Enantiomeric excess: 99% (determined by HPLC analysis using a Chiralpak AD column); mp
145–146°C; [α]D20 −320 (c 1.00, THF); 1H NMR (CDCl3/TMS) δ 0.75 (t, 3H), 2.37 (s, 3H), 3.49–3.55
(m, 1H), 3.65–3.68 (m, 1H), 5.17 (s, 2H), 7.00 (d, J=7.10 Hz, 2H), 7.07–7.18 (m, 5H), 7.40 (d, J=8.19
Hz, 2H), 7.76 (s, 1H); IR 1749 cm−1, 1614 cm−1; MS m/z 372 (M++1, 21), 299 (18), 217 (100), 155 (28),
91 (78). Anal. calcd for C19H20N2O4S: C, 61.27; H, 5.41; N, 7.52. Found: C, 61.09; H, 5.59; N, 7.32.
3.2. (4R,5R)-cis-4-(Ethoxylcarbonyl)-5-(4-chlorophenyl)-1-N-tosyl-2-imidazoline 5b
Enantiomeric excess: 99% (determined by HPLC analysis using a Chiralcel OD column); mp
139–139.5°C; [α]D20 −311 (c 1.00, THF); 1H NMR (CDCl3/TMS) δ0.80 (t, 3H), 2.39 (s, 3H), 3.54–3.77
(m, 2H), 5.11 (d, J=11.28 Hz, 1H),5.18 (d, J=11.28 Hz, 1H), 6.92 (d, J=8.32 Hz, 2H), 7.05 (d, J=8.32
Hz, 2H), 7.12 (d, J=8.06 Hz, 2H), 7.38 (d, J=8.06 Hz, 2H), 7.75 (s, 1H); IR 1750 cm−1, 1610 cm−1; MS
m/z 406 (M++1, 4), 333 (13), 251 (100), 178 (3), 155 (30), 91 (74). Anal. calcd for C19H19ClN2O4S: C,
56.08; H, 4.70; N, 6.88. Found: C, 56.24; H, 4.74; N, 6.69.
3.3. (4S,5S)-cis-4-(Ethoxylcarbonyl)-5-(4-chlorophenyl)-1-N-tosyl-2-imidazoline 5b
Enantiomeric excess: 97% (determined by HPLC analysis using a Chiralcel OD column); mp
137–138°C; [α]D20 +298 (c 0.99, THF); 1H NMR (CDCl3/TMS) δ 0.82 (t, 3H), 2.40 (s, 3H), 3.62–3.74
(m, 2H), 5.12 (d, J=11.36 Hz, 1H), 5.18 (d, J=11.36 Hz, 1H), 6.94 (d, J=8.53 Hz, 2H), 7.07 (d, J=8.53
Hz, 2H), 7.16 (d, J=8.34 Hz, 2H), 7.40 (d, J=8.34 Hz, 2H), 7.75 (d, J=1.90 Hz, 1H). Anal. calcd for
C19H19ClN2O4S: C, 56.08; H, 4.70; N, 6.88. Found: C, 56.06; H, 4.76; N, 6.78.
3.4. (4R,5R)-cis-4-(Ethoxylcarbonyl)-5-(4-bromophenyl)-1-N-tosyl-2-imidazoline 5c
Enantiomeric excess: 99% (determined by HPLC analysis using a Chiralcel OD column); mp
143–143.5°C; [α]D20 −274 (c 1.00, THF); 1H NMR (CDCl3/TMS) δ 0.82 (t, 3H), 2.41 (s, 3H), 3.59–3.77

X.-T. Zhou et al. / Tetrahedron: Asymmetry 10 (1999) 855–862
859
(m, 2H), 5.11 (d, J=11.35 Hz, 1H),5.18 (d, J=11.35 Hz, 1H), 6.87 (d, J=8.39 Hz, 2H), 7.16 (d, J=8.21
Hz, 2H), 7.21 (d, J=8.39 Hz, 2H), 7.39 (d, J=8.21 Hz, 2H), 7.75 (s, 1H); IR 1751 cm−1, 1610 cm−1; MS
m/z 451 (M+, 8), 378 (5), 155 (28), 91 (63). Anal. calcd for C19H19BrN2O4S: C, 50.56; H, 4.24; N, 6.20.
Found: C, 50.29; H, 4.16; N, 6.02.
3.5. (4S,5S)-cis-4-(Ethoxylcarbonyl)-5-(4-bromophenyl)-1-N-tosyl-2-imidazoline 5c
Enantiomeric excess: 99% (determined by HPLC analysis using a Chiralcel OD column); mp
142–143°C; [α]D20 +272 (c 0.99, THF); 1H NMR (CDCl3/TMS) δ 0.82 (t, 3H), 2.40 (s, 3H), 3.62–3.75
(m, 2H), 5.11 (d, J=11.38 Hz, 1H), 5.19 (dd, J=11.38, 2.11 Hz, 1H), 6.87 (d, J=8.48 Hz, 2H), 7.16 (d,
J=8.39 Hz, 2H), 7.21 (d, J=8.48 Hz, 2H), 7.39 (d, J=8.39 Hz, 2H), 7.75 (d, J=1.96 Hz, 1H). Anal. calcd
for C19H19BrN2O4S: C, 50.56; H, 4.24; N, 6.20. Found: C, 50.56; H, 4.22; N, 6.04.
3.6. (4R,5R)-cis-4-(Ethoxylcarbonyl)-5-(4-iodophenyl)-1-N-tosyl-2-imidazoline 5d
Enantiomeric excess: 96% (determined by HPLC analysis using a Chiralcel OD column); mp
134–135°C; [α]D20 −234 (c 1.00, THF); 1H NMR (CDCl3/TMS) δ 0.81 (t, 3H), 2.43 (s, 3H), 3.63–3.74
(m, 2H), 5.10 (d, J=11.12 Hz, 1H), 5.20 (d, J=11.12 Hz, 1H), 6.73 (d, J=8.10 Hz, 2H), 7.15 (d, J=8.10
Hz, 2H), 7.37–7.42 (m, 4H), 7.77 (s, 1H); IR 1751 cm−1, 1610 cm−1; MS m/z 498 (M++1, 8), 425 (7),
342 (100), 270 (2), 155 (18). Anal. calcd for C19H19IN2O4S: C, 45.79; H, 3.84; N, 5.62. Found: C, 45.77;
H, 3.59; N, 5.36.
3.7. General procedure for the preparation of 2,3-diamino esters from the hydrolysis of 2-imidazolines
Compound (4R,5R)-5c (500 mg) was treated with 3.5 mL of conc. HCl in 21 mL of EtOH at 60°C
for 4 h. After removal of the EtOH, the residue was added to 20 mL CH2Cl2 and neutralized with solid
NaHCO3. The solution was dried by Na2SO4 and filtration by suction. The filtrate was concentrated
and dried under vacuum to give (2R,3R)-2,3-diamino ester 6c in quant yield (49% yield based on the
N-sulfonylimine).
3.8. Ethyl (2R,3R)-2-amino-3-(N-tosylamino)-3-phenylpropionate 6a
Mp 89–90°C; [α]D −25.2 (c 1.00, THF); 1H NMR (CDCl3/TMS) δ1.20 (t, 3H), 1.61 (br, NH), 2.31
20
(s, 3H), 3.74 (s, 1H), 4.00–4.09 (m, 2H), 4.88 (d, J=3.82 Hz, 1H), 6.11 (br, NH), 6.98–7.16 (m, 7H), 7.53
(d, J=8.30 Hz, 2H); MS m/z 362 (M+, 100), 260 (36), 155 (34), 91 (62). Anal. calcd for C18H22N2O4S:
C, 59.64; H, 6.11; N, 7.72. Found: C, 59.82; H, 5.86; N, 7.86.
3.9. Ethyl (2R,3R)-2-amino-3-(N-tosylamino)-3-(4-chlorophenyl)propionate 6b
20
Mp 107–108°C; [α]D −24.6 (c 1.00, THF); 1H NMR (CDCl3/TMS) δ 1.20 (t, 3H), 1.75 (br, NH),
2.34 (s, 3H), 3.77 (s, 1H), 4.03–4.08 (m, 2H), 4.87 (s, 1H), 6.04 (br, NH), 6.93 (d, J=8.34 Hz, 2H),
7.05–7.09 (m, 4H), 7.50 (d, J=8.15 Hz, 2H); MS m/z 396 (M+, 8), 323 (0.5), 294(93), 155(91), 102(18),
91(100). Anal. calcd for C18H21N2O4SCl: C, 54.47; H, 5.33; N, 7.06. Found: C, 54.54; H, 5.35; N, 6.97.

860
X.-T. Zhou et al. / Tetrahedron: Asymmetry 10 (1999) 855–862
3.10. Ethyl (2S, 3S)-2-amino-3-(N-tosylamino)-3-(4-chlorophenyl)propionate 6b
20
Mp 105–106°C; [α]D +22.6 (c 1.00, THF); 1H NMR (CDCl3/TMS) δ 1.12 (t, 3H), 1.60 (br, NH),
2.27 (s, 3H), 3.73 (s, 1H), 3.97–4.00 (m, 2H), 4.78 (s, 1H), 6.05 (br, NH), 6.86 (d, J=8.30 Hz, 2H),
6.97–7.02 (m, 4H), 7.20 (d, J=8.10 Hz, 2H). Anal. calcd for C18H21N2O4SCl: C, 54.47; H, 5.33; N, 7.06.
Found: C, 54.52; H, 5.09; N, 6.81.
3.11. Ethyl (2R,3R)-2-amino-3-(N-tosylamino)-3-(4-bromophenyl)propionate 6c
Mp 91–92°C; [α]D20 −21.4 (c 1.00, THF); 1H NMR (CDCl3/TMS) δ 1.22 (t, 3H), 1.78 (br, NH), 2.35
(s, 3H), 3.75 (s, 1H), 4.00–4.11 (m, 2H), 4.84 (s, 1H), 6.15 (br, NH), 6.86 (d, J=8.32 Hz, 2H), 7.07 (d,
J=8.14 Hz, 2H), 7.20 (d, J=8.32 Hz, 2H), 7.48 (d, J=8.14 Hz, 2H); MS m/z 396 (M+, 8), 323 (0.5), 294
(93), 155 (91), 102 (18), 91 (100). Anal. calcd for C18H21N2O4SBr: C, 48.98; H, 4.79; N, 6.34. Found:
C, 49.02; H, 4.77; N, 6.38.
3.12. Ethyl (2S,3S)-2-amino-3-(N-tosylamino)-3-(4-bromophenyl)propionate 6c
Mp 89–90°C; [α]D20 +20.2 (c 1.00, THF); 1H NMR (CDCl3/TMS) δ 1.13 (t, 3H), 1.75 (br, NH), 2.28
(s, 3H), 3.70 (s, 1H), 3.97–4.00 (m, 2H), 4.78 (s, 1H), 6.05 (br, NH), 6.79 (d, J=8.30 Hz, 2H), 7.00 (d,
J=8.2 Hz, 2H), 7.13 (d, J=8.30 Hz, 2H), 7.42 (d, J=8.20 Hz, 2H). Anal. calcd for C18H21N2O4SBr: C,
48.98; H, 4.79; N, 6.34. Found: C, 48.85; H, 4.47; N, 6.15.
3.13. Ethyl (2R,3R)-2-amino-3-(N-tosylamino)-3-(4-iodophenyl)propionate 6d
Mp 112–113°C; [α]D −19.2 (c 1.00, THF); 1H NMR (CDCl3/TMS) δ 1.23 (t, 3H), 1.61 (br, NH),
20
2.37 (s, 3H), 3.73 (s, 1H), 4.01–4.10 (m, 2H), 4.83 (s, 1H), 6.11 (br, NH), 6.73 (d, J=8.23 Hz, 2H), 7.07
(d, J=8.14 Hz, 2H), 7.40 (d, J=8.14 Hz, 2H), 7.48 (d, J=8.23 Hz, 2H); MS m/z 488 (M++1, 6), 386 (6),
155 (46), 91 (100). Anal. calcd for C18H21N2O4SI: C, 44.27; H, 4.33; N, 5.73. Found: C, 44.48; H, 4.39;
N, 5.55.
3.14. General reduction procedure with LiAlH4 as follows
Compound (2R,3R)-6c (380 mg) was dissolved in 3 mL THF, and added dropwise to a mixture of 65
mg LiAlH4 in 2 mL of THF at 0°C while stirring. The mixture was refluxed for 5 h, and hydrolyzed at
0°C by slow, successive addition of 0.4 mL H2O, 0.4 mL 15% NaOH aqueous and 0.8 mL H2O. The
precipitates formed were removed by filtration and washed with a mixture of EtOH:conc. HCl (20:1).
The filtrate was concentrated and neutralized with 5% aq. NaHCO3 to form a white solid. The white
solid was obtained by filtration, washed with water and Et2O, and dried under vacuum to give 278 mg of
(2R,3R)-7c in an 81% yield.
3.15. (2R,3R)-2-Amino-3-(N-tosylamino)-3-phenylpropanol 7a
20
1
83% Yield; [α]D −4.1 (c 1.00, EtOH in 0.1 ml conc. HCl); H NMR (DMSO-d6) δ 2.28 (s, 3H),
2.84 (m, 1H), 3.10 (m, 2H), 3.32 (br, OH), 4.27 (d, J=5.91 Hz, 1H), 7.10–7.17 (m, 7H), 7.44 (d, J=8.27
Hz, 2H); MS m/z 320 (M++1, 4), 260 (1), 155 (6), 91 (36). HRMS calcd for (C15H17N2SO3, M+−CH3):
305.0959; found 305.0938.

X.-T. Zhou et al. / Tetrahedron: Asymmetry 10 (1999) 855–862
861
3.16. (2R,3R)-2-Amino-3-(N-tosylamino)-3-(4-chlorophenyl)propanol 7b
20
1
85% Yield; [α]D −3.2 (c 1.00, EtOH in 0.1 mL conc. HCl); H NMR (DMSO-d6) δ 2.30 (s, 3H),
2.84 (m, 1H), 3.10 (m, 2H), 3.33 (br, OH), 4.25 (d, J=5.87 Hz, 1H), 7.07–7.17 (m, 6H), 7.42 (d, J=7.96
Hz, 2H); MS m/z 354 (M++1, 20), 294 (1), 155 (6). HRMS calcd for (C16H20N2ClSO3, M++1): 355.0883;
found 355.0896.
3.17. (2R,3R)-2-Amino-3-(N-tosylamino)-3-(4-bromophenyl)propanol 7c
20
1
81% Yield; [α]D −3.7 (c 0.97, EtOH in 0.1 mL conc. HCl); H NMR (DMSO-d6) δ 2.31 (s, 3H),
2.84 (m, 1H), 3.10 (m, 2H), 3.32 (br, OH), 4.24 (d, J=5.84 Hz, 1H), 7.02 (d, J=8.35 Hz, 2H), 7.15 (d,
J=8.13 Hz, 2H), 7.27 (d, J=8.35 Hz, 2H), 7.41 (d, J=8.13 Hz, 2H); MS m/z 399 (M++1, 1), 155 (6), 91
(36). HRMS calcd for (C16H20N2BrSO3, M++1): 399.0378; found 399.0377.
3.18. (2R,3R)-3-Phenyl-2,3-diamino acid 8a
71% Yield; mp 192–193°C (dec.); [α]D20 −8.0 (c 0.65, 6 N HCl); 1H NMR (300 MHz/D2O) δ 3.91 (d,
J=7.00 Hz, 1H), 4.53 (d, J=7.00 Hz, 1H), 7.43–7.55 (m, 5H); 13C NMR (300 MHz/D2O) δ 58.9, 61.1,
130.1, 131.9, 138.1, 177.7; FAB-MS 181 (M++1), 164 (M+−16), 148 (M+−32).
Acknowledgements
Financial support from National Natural Science Foundation of China (project number 29772046)
and Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry are gratefully
acknowledged.
References
1. (a) Wang, M.; Gould, S. J. J. Org. Chem. 1993, 58, 5176. (b) Rane, D. F.; Girijavallabhan, V. M.; Ganguly, A. K.; Pike,
R. E.; Saksena, A. K.; McPhall, A. T. Tetrahedron Lett. 1993, 34, 3201. (c) Baldwin, J. E.; Adlington, R. M.; Birch, D. J.
Tetrahedron Lett.1985, 26, 5931. (d) Baldwin, J. E.; Adlington, R. M.; Birch, D. J. J. Chem. Soc., Chem. Commun. 1985,
256. (e) Pfammatter, E.; Seebach, D. Liebigs. Ann. Chem. 1991, 1323. (f) Webber, S. E.; Okano, K.; Little, T. L.; Reich,
S. H.; Xin, Y.; Fuhrman, S. A.; Matthews, D. A.; Love, R. A.; Hendrickson, T. F.; Patick, A. K.; Meador, J. M.; Ferre, R.
A.; Brown, E. L.; Ford, C. E.; Binford, S. L.; Worland, S. T. J. Med. Chem. 1998, 41, 2786 and references cited therein.
2. (a) Martin, J. H.; Hausmann, W. K. J. Am. Chem. Soc. 1960, 82, 2079. (b) Inoue, M.; Hitomi, H.; Mizuno, K.; Fujino,
M.; Miyake, A.; Nakazawa, K.; Shibata, M.; Kanzaki, T. Bull. Chem. Soc. Jpn. 1960, 33, 1014. (c) Fujino, M.; Inoue,
M.; Veyanagi, J.; Miyake, A. Bull. Chem. Soc. Jpn. 1961, 34, 740. (d) Inoue, M. Bull. Chem. Soc. Jpn. 1961, 34, 885. (e)
Inoue, M. Bull. Chem. Soc. Jpn. 1962, 35, 1556. (f) Fujino, M.; Inoue, M.; Ueyangi, J.; Miyake, A. Bull. Chem. Soc. Jpn.
1965, 38, 515. (g) Uchida, L.; Shigematsu, N.; Ezaki, M.; Hashimoto, M. Chem. Pharm. Bull. 1985, 33, 3053.
3. Palomo, C.; Aizpurua, J. M.; Cabre, F.; Cuevas, C.; Munt, S.; Odriozola, J. M. Tetrahedron Lett. 1994, 35, 2725.
4. Dunn, P. J.; Haner, R.; Rapoport, H. J. Org. Chem. 1990, 55, 5017.
5. Merino, P.; Lanaspa A.; Merchan, F. L.; Tejero, T. Tetrahedron: Asymmetry 1998, 9, 629.
6. (a) Nakamura, Y.; Shin, C. Chem. Lett. 1992, 49. (b) Nakamura, Y.; Hirai, M.; Tamotsu, K.; Yonezawa, Y.; Shin, C. Bull.
Chem. Soc. Jpn. 1995, 68, 1369. (c) Schmidt, U.; Mundinger, K.; Mangold, R.; Lieberknecht, A. J. Chem. Soc., Chem.
Commun. 1996, 1216. (d) Schmidt, U.; Mundinger, K.; Riedi, B.; Haas, G.; Lau, Palomo, C. Synthesis 1992, 1201.
7. Han, H.; Yoon, J.; Janda K. D. J. Org. Chem. 1998, 63, 2045.
8. Alker, D.; Harwood, L. M.; Williams, C. E. Tetrahedron Lett. 1998, 39, 475.
9. Moyna, G.; Williams, H. J.; Scott, A. I. Synth. Commun. 1997, 27, 156.

862
X.-T. Zhou et al. / Tetrahedron: Asymmetry 10 (1999) 855–862
10. Kuwano, R.; Okuda, S.; Ito, Y. Tetrahedron: Asymmetry 1998, 9, 2774.
11. Ito, Y.; Sawamura, M.; Hayashi, T. J. Am. Chem. Soc. 1986, 108, 6405.
12. Hayashi, T.; Kishi, E.; Soloshonok, V. A.; Uozumi, Y. Tetrahedron Lett. 1996, 37, 4969.
13. Zhou, X.-T.; Lin, Y.-R.; Dai, L.-X.; Sun, J.; Xia, L.-J.; Tang, M.-H. J. Org. Chem. 1999, 64, 1331.
14. Jefford, C. W.; McNulty, J. Helv. Chim. Acta. 1994, 77, 2142.
15. (a) Ager D. J.; Prakash, I.; Schaad, D. R. Chem. Rev. 1996, 96, 835. (b) Noyori, R.; Kitamura, M. Angew. Chem., Int. Ed.
Engl. 1991, 49.
16. (a) Masui, M.; Shioiri, T. Tetrahedron Lett. 1998, 39, 5195. (b) Masui, M.; Shioiri, T. Tetrahedron Lett. 1998, 39, 5199.
(c) Kim, B. M.; Bae, S. J.; Seomoon, G. Tetrahedron Lett. 1998, 39, 6921. (d) Laib, T.; Ouazzani, J.; Zhu, J. Tetrahedron:
Asymmetry 1998, 9, 169 and references cited therein. (e) Reddy, K. L.; Sharpless, K. B. J. Am. Chem. Soc. 1998, 120, 1207
and references cited therein.
17. Bonati, F.; Minghetti, G. Gazz. Chim. Ital. 1973, 103, 373.
18. Hayashi, T.; Yamazaki, A. J. Organomet. Chem. 1991, 413, 295.
19. Love, B. E.; Raje, P. S.; Williams II, T. C. Synlett, 1994, 493. (b) Jennings, W. B.; Lovely, C. T. Tetrahedron Lett. 1988,
29, 3725.
20. Hartman, G. D.; Weinstock, L. M. Org. Synth. 1988, 6, 620.