Nitrile biotransformations for highly efficient and enantioselective syntheses of electrophilic oxiranecarboxamides

Article abstract of DOI:10.1021/jo0267201

Catalyzed by a nitrile hydratase/amidase-containing microbial Rhodococcus sp. AJ270 whole-cell catalyst, a number of racemic trans-2,3-epoxy-3-arylpropanenitriles 1 underwent rapid and efficient hydrolysis under very mild conditions to afford 2R,3S-2-arylglycidamides 2 in excellent yield with enantiomeric excess higher than 99.5%. The overall enantioselectivity of the biotransformations originated from the combined effects of a dominantly high 2S-enantioselective amidase and low 2S-enantioselective nitrile hydratase involved in the cell. The influence of the substrates on both reaction efficiency and enantioselectivity was also discussed in terms of steric and electronic effects.

Full text of DOI:10.1021/jo0267201

ylate,8 and isoserine derivatives.1c,9 It is also intriguing
to note that the phenylglycidamide structure has recently
been found to occur in natural products. Examples
include SB-20490010 and prebalamide,11 which were
isolated respectively from the plant Clusena lansium
and Clausena indica, whose leaves and fruit have been
used to treat asthma and viral hepatitis.
Nitr ile Biotr a n sfor m a tion s for High ly
Efficien t a n d En a n tioselective Syn th eses of
Electr op h ilic Oxir a n eca r boxa m id es
Mei-Xiang Wang,* Shuang-J un Lin, Chu-Sheng Liu,
Qi-Yu Zheng, and J i-Sheng Li
Laboratory for Chemical Biology, Center for Molecular
Science, Institute of Chemistry, Chinese Academy of
Sciences, Beijing 100080, China
Although the preparation of enantiopure epoxide com-
pounds has been well-developed by Sharpless and others,
no general and single approach stands out for the
synthesis of optically active electrophilic epoxides.12
J acobsen1b reported that the (salen)Mn(III)-catalyzed
asymmetric epoxidation of substituted cis-cinnamate
esters gave a mixture of cis- and trans-arylglycidic esters
with enantiomeric excess values (ee) ranging from 41 to
97%, and the ratio of cis to trans isomers was governed
by the nature of the ester group and by the substituent
on the benzene ring. Epoxidation of trans-cinnamate
esters with chiral dioxiranes and MCPBA localized in an
egg phosphatidylcholine liposomal bilayer afforded trans-
arylglycidic esters with moderate to good ee values.13 The
reactions between chiral sulfonium ylides and alde-
hydes14 and between sulfonium ylides and chiral alde-
hydes15 have been employed to prepare enantiomerically
enriched oxiranecarboxamides but only moderate ee
values and diastereomeric excess values (des) were
obtained, respectively. Extended from their early findings
of epoxidation of electrophilic alkenes with lithium tert-
butylhydroperoxide, Meth-Cohn and co-workers have
recently reported a diastereoselective epoxidation of
trans-cinnamamides using prolinols or prolineanilide as
a chiral auxiliary. Catalyzed by the lipase from Candida
cylindracea, racemic trans-4-methoxyphenyl- and -phe-
nylglycidic esters were hydrolyzed to give optically active
2R,3S esters in good yields,18 while the kinetic resolution
of racemic trans-arylglycidic acid amides catalyzed by the
mxwang@iccas.ac.cn
Received November 14, 2002
Ab st r a ct : Catalyzed by a nitrile hydratase/amidase-
containing microbial Rhodococcus sp. AJ 270 whole-cell
catalyst, a number of racemic trans-2,3-epoxy-3-arylpro-
panenitriles 1 underwent rapid and efficient hydrolysis
under very mild conditions to afford 2R,3S-2-arylglycida-
mides 2 in excellent yield with enantiomeric excess higher
than 99.5%. The overall enantioselectivity of the biotrans-
formations originated from the combined effects of a domi-
nantly high 2S-enantioselective amidase and low 2S-
enantioselective nitrile hydratase involved in the cell. The
influence of the substrates on both reaction efficiency and
enantioselectivity was also discussed in terms of steric and
electronic effects.
Enantiomerically pure electrophilic epoxides are im-
portant and versatile intermediates in organic synthesis.
Oxiranecarboxamides and oxiranecarboxylic acid esters,
for example, are the key building blocks in the synthesis
of natural products such as the Taxol side chain,1 (-)-
dehydroclausenamide,2 (+)-neoclausenamide,3 and (+)-
clausenamide,4 synthetic pharmaceuticals such as dil-
tiazem,1b,5 a potent coronary vasodilating agent, and
SK&F 104353,6 a potent and selective leukotriene an-
tagonist. Selective chemical transformation and ring-
opening reactions of electrophilic oxiranes also provide
powerful and efficient routes to a variety of useful com-
pounds including 2,3-epoxyketone,7 aziridinecarbox-
(8) Thijs, L.; Porskamp, J . J . M.; van Loon, A. A. W. M.; Derks, M.
P. W.; Feenstra, R. W.; Legters, J .; Zwanenburg, B. Tetrahedron 1990,
46, 2611.
(9) Bhatia, B.; J ain, S.; De, A.; Bagchi, I.; Iqbal, J . Tetrahedron Lett.
1996, 37, 7311.
(10) Milner, P. H.; Gilpin, N. J .; Spear, S. R.; Eggleston, D. S. J .
Nat. Prod. 1996, 59, 400.
* To whom correspondence should be addressed. Phone: +86-10-
62554628. Fax: +86-10-62564723.
(1) (a) Deng, L.; J acobsen, E. N. J . Org. Chem. 1992, 57, 4320. (b)
J acobsen, E. N.; Deng, L.; Furukawa, Y.; Martinez, L. E. Tetrahedron
1994, 50, 4323. (c) Righi, G.; Rumboldt, G.; Bonini, C. J . Org. Chem.
1996, 61, 3557.
(2) Huang, D.-F.; Huang, L. Tetrahedron 1990, 46, 3135.
(3) Wang, J .; Tian, W. J . Chem. Soc., Perkin Trans. 1 1996, 209.
(4) Cappi, M. W.; Chen, W.-P.; Flood, R. W.; Liao, Y.-W.; Roberts,
S. M.; Skidmore, J .; Smith, J . A.; Williamson, N. M. Chem. Commun.
1998, 1159.
(5) (a) Hashiyama, T.; Inoue, H.; Konda, M.; Takeda, M. J . Chem.
Soc., Perkin Trans. 1 1984, 1725. (b) Yamada, S.; Yoshioka, R.;
Shibatani, T. (Tanabe Seiyaku Co., Ltd. J apan), EP 0792876A2, 1997.
(c) Matsumae, H.; Idei, A.; Nishida, T.; Ozaki, Y.; Shibatani, T. (Tanabe
Seiyaku Co., Ltd. J apan), EP 0795609A2, 1997.
(6) (a) Gleason, J . G.; Hall, R. F.; Perchonock, C. D.; Erhard, K. F.;
Frazee, J . S.; Ku, T. W.; Kondrad, K.; McCarthy, M. E.; Mong, S.;
Crooke, S. T.; Chi-Rosso, G.; Wasserman, M. A.; Torphy, T. J .;
Muccitelli, R. M.; Hay, D. W.; Tucker, S. S.; Vickery-Clark, L. J . Med.
Chem. 1987, 30, 959. (b) Kolb, H. C.; Sharpless, K. B. Tetrahedron
1992, 48, 10515. (c) Flisak, J . R.; Gombatz, K. J .; Holmes, M. M.;
J armas, A. A.; Lantos, I.; Mendelson, W. L.; Novack, V. J .; Remich, J .
J .; Snyder, L. J . Org. Chem. 1993, 58, 6247.
(11) Riemer, B.; Hofer, O.; Greger, H. Phytochemistry 1997, 45, 337.
(12) For a recent review, see: (a) Porter, M. J .; Skidmore, J . Chem.
Commun. 2000, 1215. For examples of asymmetric epoxidation of R,â-
unsaturated ketones, see: (b) Enders, D.; Zhu, J .; Raabe, G. Angew.
Chem., Int. Ed. Engl. 1996, 35, 1725. (c) Yu, H.-B.; Zheng, X.-F.; Lin,
Z.-M.; Hu, Q.-S.; Huang, W.-S.; Pu, L. J . Org. Chem. 1999, 64, 8149.
(d) Watanabe, S.; Kobayashi, Y.; Arai, T.; Sasai, H.; Bougauchi, M.;
Shibasaki, M. Tetrahedron Lett. 1998, 39, 7353. (e) Watanabe, S.; Arai,
T.; Sasai, H.; Bougauchi, M.; Shibasaki, M. J . Org. Chem. 1998, 63,
8090. (f) Elston, C. L.; J ackson, R. F. W.; MacDonald, S. J . F.; Murray,
P. J . Angew. Chem., Int. Ed. Engl. 1997, 36, 410. (g) Wang, Z.-X.;
Miller, S. M.; Anderson, O. P.; Shi, Y. J . Org. Chem. 1999, 64, 6443
and references therein.
(13) Kumar, A.; Bhakuni, V. Tetrahedron Lett. 1996, 37, 4571.
(14) Zhou, Y.-G.; Hou, X.-L.; Dai, L.-X.; Xia, L.-J .; Tang, M.-H. J .
Chem. Soc., Perkin Trans. 1 1999, 77.
(15) Fernandez, M. V.; Durante-Lanes, P.; Lopez-Herrera, F. J .
Tetrahedron 1990, 46, 7911.
(16) Meth-Cohn, O.; Moore, C.; Taljaard, H. C. J . Chem. Soc., Perkin
Trans. 1 1988, 2663.
(17) Meth-Cohn, O.; Williams, D. J .; Chen, Y. Chem. Commun. 2000,
495.
(18) Gentile, A.; Giordano, C.; Fuganti, C.; Ghirotto, L.; Servi, S. J .
Org. Chem. 1992, 57, 6635.
(7) Meth-Cohn, O.; Chen, Y. Tetrahedron Lett. 1999, 40, 6069.
10.1021/jo0267201 CCC: $25.00 © 2003 American Chemical Society
Published on Web 05/02/2003
4570
J . Org. Chem. 2003, 68, 4570-4573

TABLE 1. Biotr a n sfor m a tion s of Ra cem ic tr a n s-2,3-Ep oxy-3-a r ylp r op a n en itr iles 1
2
entry
1
Ar
C6H5
C6H5
C6H5
reaction conditionsa
yield (%)b
ee (%)c
1
2
3
4
5
6
7
8
9
1a
1a
1a
1a
1b
1b
1c
1d
1e
1f
2 mmol, 25 mL of buffer (pH 7.0), 5.3 h
2 mmol, 25 mL of buffer (pH 7.0), 25 mL of hexane, 5.2 h
2 mmol, 50 mL of buffer (pH 7.25), 27 min
2 mmol, 50 mL of buffer (pH 7.25), 6.5 h
1 mmol, 50 mL of buffer (pH 7.25), 3 h
2 mmol, 25 mL of buffer (pH 7.25), 5 h
2 mmol, 50 mL of buffer (pH 7.25), 24 h
2 mmol, 50 mL of buffer (pH 7.25), 6 h
2 mmol, 50 mL of buffer (pH 7.25), 10 h
2 mmol, 50 mL of buffer (pH 7.25), 80 h
42
42
76d
45
47
47
60
47
49
61
96.4
99.5
19.5d
>99.5
>99.5
>99.5
39.9
C6H5
4-Me-C6H4
4-Me-C6H4
2-Me-C6H4
4-F-C6H4
4-Cl-C6H4
3-Cl-C6H4
>99.5
>99.5
31.3
10
a
b
Rhodococcus sp. AJ 270 cells (2 g wet weight) were used. Isolated yield. c Determined by HPLC analysis with use of a Chiralcel OD
d
column. 2R,3S-Nitrile 1a (9% yield, 55.1% ee) was recovered.
SCHEME 1. Biotr a n sfor m a tion s of Ra cem ic
tr a n s-2,3-Ep oxy-3-a r ylp r op a n en itr iles 1
metric chemical and enzymatic synthetic methods for
carboxylic acids and their derivatives. The distinct
features of enzymatic transformations of nitriles are the
formation of enantiopure carboxylic acids, and the straight-
forward generation of enantiopure amides, which are
valuable organonitrogen compounds in synthetic chem-
istry. Our interests23 in enantioselective biotransforma-
tions of nitriles using microbial cells and in utilizing this
methodology to create unique and versatile chiral orga-
nonitrogen compounds have led us to investigate the
biotransformation of oxiranecarbonitriles. In this paper
we report highly efficient and convenient synthesis of
enantiopure electrophilic oxiranecarboxamides.
SCHEME 2. Bioca ta lytic Kin etic Resolu tion of
Ra cem ic tr a n s-2,3-Ep oxy-3-a r ylp r op a n a m id e (2a )
We first examined the reaction of racemic trans-2,3-
epoxy-3-phenylpropanenitrile (1a ).24 Catalyzed by the
Rhodococcus sp. AJ 270, a nitrile hydratase/amidase-
containing microbial whole cell catalyst,25 under very
mild conditions, nitrile 1a was converted efficiently into
the optically active 2R,3S-2-phenylglycidamide (2a ).5c
The corresponding phenylglycidic acid 3a was not ob-
tained because it underwent spontaneous decomposition
to phenylacetaldehyde under the reaction conditions as
reported in the literature18 (Scheme 1). As indicated in
Table 1, although the biotransformation of 1a took place
effectively under various conditions such as in aqueous
phosphate buffer with pH 7.0 (entry 1) or in a biphasic
system of phosphate buffer (pH 7.0) with hexane (entry
2), the best chemical yield (45%) with highest enantio-
meric excess (ee >99.5%) was obtained for 2a when the
reaction was conducted in phosphate buffer at pH 7.25
(entry 4). To understand the outcome of the stereochem-
istry of both the nitrile hydratase and the amidase
involved in Rhodococcus sp. AJ 270 cells, the reaction of
1a was quenched in 27 min. The optically active 2R,3S-
2-phenylglycidamide (2a , 76%) thus isolated and recov-
ered 2R,3S-nitrile 1a (9%) showed an enantiomeric excess
value of 19.5 and 55.1%, respectively (entry 3). Chemical
hydrolysis of 2R,3S-nitrile 1a (ee 55.1%) recovered from
biotransformation afforded 2R,3S-2-phenylglycidamide
(2a , ee 57.1%) in 75% yield. We then investigated the
biotransformation of racemic 2a under the identical
conditions, and found that (()-2a was resolved after 6 h
into enantiopure 2R,3S-2-phenylglycidamide (2a ) in 43%
yield (Scheme 2). This indicated clearly that the amidase
amidase led to optically active amides with varied enan-
tiomeric purity.5c
Biotransformations of nitriles, either through a direct
conversion from a nitrile to a carboxylic acid catalyzed
by a nitrilase19 or through the nitrile hydratase-catalyzed
hydration of a nitrile followed by the amide hydrolysis
catalyzed by the amidase,20 are effective and environ-
mentally benign methods for the production of carboxylic
acids and their amide derivatives. The microbial hydra-
tion of acrylonitrile to acrylamide, for instance, is one of
the largest industrial biotransformations in the world.21
Recent studies22,23 have demonstrated that biotransfor-
mations of nitriles also complement the existing asym-
(19) Kobayashi, M.; Shimizu, S. FEMS Microbiol. Lett. 1994, 120,
217 and references therein.
(20) (a) Meth-Cohn, O.; Wang, M.-X. J . Chem. Soc., Perkin Trans.
1 1997, 1099-1104. (b) Meth-Cohn, O.; Wang, M.-X. J . Chem. Soc.,
Perkin Trans. 1 1997, 3197 and references therein.
(21) Nagasawa, T.; Schimizu, H.; Yamada, H. Appl. Microbiol.
Biotechnol. 1993, 40, 189.
(22) Sugai, T.; Yamazaki, T.; Yokoyama, M.; Ohta, H. Biosci.
Biotechnol. Biochem. 1997, 61, 1419 and references therein.
(23) (a) Wang, M.-X.; Lin, S.-J . J . Org. Chem. 2002, 67, 6542. (b)
Wang, M.-X.; Zhao, S.-M. Tetrahedron Lett. 2002, 43, 6617. (c) Wang,
M.-X.; Zhao, S.-M. Tetrahedron: Asymmetry 2002, 13, 1695. (d) Wang,
M.-X.; Li, J .-J .; J i, G.-J .; Li, J .-S. J . Mol. Catal. B: Enzymol. 2001, 14,
77. (e) Wang, M.-X.; Lin, S.-J . Tetrahedron Lett. 2001, 42, 6925. (f)
Wang, M.-X.; Liu, C.-S.; Li, J .-S. Tetrahedron: Asymmetry 2001, 12,
3367. (g) Wang, M.-X.; Lu, G.; J i, G.-J .; Huang, Z.-T.; Meth-Cohn, O.;
Colby, J . Tetrahedron: Asymmetry, 2000, 11, 1123. (h) Wang, M.-X.;
Feng, G.-Q. Tetrahedron Lett. 2000, 41, 6501. (i) Wang, M.-X.; Feng,
G.-Q. New J . Chem. 2002, 1575. (j) Wang, M.-X.; Liu, C.-S.; Li, J .-S.;
Meth-Cohn, O. Tetrahedron Lett. 2000, 41, 8549.
(24) Svoboda, J .; Kocfeldova´, Z.; Palecˇek, J . Collect. Czech. Chem.
Commun. 1988, 53, 822.
(25) Blakey, A. J .; Colby, J .; Williams, E.; O’Reilly, C. FEMS
Microbiol. Lett. 1995, 129, 57.
J . Org. Chem, Vol. 68, No. 11, 2003 4571

SCHEME 3. Biotr a n sfor m a tion s of Ra cem ic
cis-2,3-Ep oxy-3-a r ylp r op a n en itr iles 4
SCHEME 4. Biotr a n sfor m a tion s of a Mixtu r e of
Ra cem ic tr a n s- a n d
cis-2,3-Ep oxy-3-a r ylp r op a n en itr iles
of Rhodococcus sp. AJ 270 displays high 2S-enantioselec-
tivity against trans-2-phenylglycidamide while the nitrile
hydratase shows low 2S-enantioselectivity against nitrile.
The excellent enantioselection of the biotransformation
of nitrile 1a originates from the combined effects of
enantioselective nitrile hydratase and amidase, with the
later being dominant.
mixture of trans- and cis-2,3-epoxy-3-(4-chlorophenyl)-
propanenitriles (1e and 4e), obtained directly from the
Darzens reaction,24 was subjected to biocatalysis, with
the hope of achieving asymmetric synthesis of enan-
tiopure glycidamide and the easy separation of pure cis-
nitrile in one operation. To our delight, biotransformation
did produce optically active amide 2e in both excellent
chemical yield (88% based on theoretical yield) and
enantiomeric purity (ee 96.6%) after quenching the
reaction in 14 h. Pure cis-nitrile 4e was also readily
obtained in high yield (80% based on theoretical yield)
(Scheme 4). The successful reaction allowed us to prepare
enantiomerically enriched amides 2 while avoiding the
somewhat tedious chromatographic separation of trans-
and cis-isomers of nitriles prior to biotransformations.
In summary, a highly efficient and convenient synthe-
sis of enantiopure 2R,3S-2-arylglycidamides has been
developed with the biotransformations of racemic nitriles
with use of a Rhodococcus sp. AJ 270 whole cell catalyst
under very mild conditions. The overall enantioselectivity
of the biotransformations originated from the combined
effects of a dominantly high 2S-enantioselective amidase
and low 2S-enantioselective nitrile hydratase involved
in the cell. We have also shown that both the nitrile
hydratase and the amidase are sensitive toward the
structure of the substrates. The enantiopure electrophilic
2R,3S-2-arylglycidamides, hardly accessible by other
methods, can serve as versatile chiral synthons, and their
applications in synthesis are actively investigated in this
laboratory.
To test the scope of the reaction and the influence of
substituent on the efficiency and enantioselectivity of
biotransformations, a number of racemic trans-2,3-epoxy-
3-arylpropanenitriles 1 were prepared24 and subjected to
incubation with Rhodococcus sp. AJ 270 (Scheme 1). It is
interesting to note that it is the substitution pattern
rather than the nature of the substituent on the benzene
ring of the substrate that plays a crucial role in deter-
mining both the reaction rate and the enantioselectivity.
As illustrated in Table 1, nitrile 1a and all its para-
substituted analogues 1b,d ,e underwent a very rapid
hydrolysis to give an almost quantitative yield of amide
in enantiomerically pure form. With a substituent at the
ortho- or meta-position, substrates 1c and 1f took a
longer incubation time to give amides 2c and 2f, respec-
tively, with only moderate enantiomeric excesses. This
suggested that the enzymes involved are very sensitive
toward the steric effect of the substrates, even with a
substituent being remote from the cyano or amido func-
tion group. The analogous phenomenon has been ob-
served in the biohydrolysis of trans-2-arylcyclopropane-
carbonitrile derivatives.23i
In contrast to the racemic trans-2,3-epoxy-3-arylpro-
panenitriles 1, the biotransformation with the racemic
cis-2,3-epoxy-3-arylpropanenitrile substrates 4 proceeded
very sluggishly. Under the same reaction conditions as
those for 1, both 2,3-epoxy-3-phenyl- (4a ) and -3-(4-
fluorophenyl)propanenitrile (4d ) compounds were not
completely hydrated after 6 days of interaction with the
whole cell catalyst, and about one-fourth of the optically
inactive nitriles 4 was recovered. This indicated a steric
restriction of the nitrile hydratase toward the nitrile
substrates. More unexpectedly, the corresponding amides
5a and 5d obtained were optically inactive (Scheme 3)!
A similar result for the very slow and nonenantioselec-
tive reaction was also obtained from the biohydrolysis
employing racemic cis-2,3-epoxy-3-phenylpropanamide
(()-5a as the substrate. This is in sharp contrast to the
biotransformation of cis-2-arylcyclopropanecarbonitriles,23i
which led to excellent enantioselectivity in a similarly
lengthy reaction time. The dramatic effect on the enan-
tioselectivity of the amidase caused by the change of one
carbon into the oxygen in the three-membered-ring
structure remains unclear at the current stage though
the change of polarity of the molecule may be important.
To take advantage of the huge difference in hydration
reaction rate between trans- and cis-nitrile isomers, a
Exp er im en ta l Section
Gen er a l. Both melting points and boiling points are uncor-
rected. Elemental analyses were performed at the Analytical
Laboratory of the Institute. The enantiomeric excesses of all
compounds were obtained with a Shimadzu LC-10AVP HPLC
system, using a Chiracel OD column. A mixture of hexane:2-
propanol [9:1] as the mobile phase at a flow rate of 0.8 mL/min
was employed.
The starting nitriles were prepared following a literature
method.24 The racemic amides were prepared from chemical
hydrolysis of nitriles.26
Gen er a l P r oced u r e for t h e Biot r a n sfor m a t ion s of
Nitr iles or Am id es. To an Erlenmeyer flask (150 mL) with a
screw cap was added Rhodococcus sp. AJ 270 cells25 (2 g wet
weight) and potassium phosphate buffer (0.1 M, pH 7.25,
50 mL), and the resting cells were activated at 30 °C for 0.5 h
with orbital shaking. Racemic nitriles 1 or 4 or amides 2a or 5a
as fine powder were added in one portion to the flask and the
mixture was incubated at 30 °C with use of an orbital shaker
(200 rpm). The reaction, monitored by TLC and HPLC, was
(26) Cativiela, C.; Diaz-de-Villegas, M. D.; Galvez, J . A. Tetrahedron:
Asymmetry 1994, 5, 261.
4572 J . Org. Chem., Vol. 68, No. 11, 2003

quenched after a specified period of time (see Table 1 and text)
by removing the biomass through a Celite pad filtration. The
resulting aqueous solution was extracted with ethyl acetate (3
× 75 mL). After the solution was dried (MgSO4) and the solvent
removed under vacuum, the residue was chromatographied on
a silica gel column with a mixture of petroleum ether and ethyl
acetate as the mobile phase to give pure product 2 or 5,
respectively. All products were characterized by their spectra
data and comparison of the melting points and optical rotary
power with that of the known compounds, which are listed as
follows, or by full characterization.
2R,3S-(-)-3-P h en ylglycid a m id e (2a ): 6.5 h; yield 45.4%;
mp 157-158 °C; [R]25D -160° (c 0.5, CH3OH); ee >99.5% (chiral
HPLC analysis); 1H NMR (300 MHz, CDCl3, TMS) δ 7.26-7.41
(m, 5H), 6.20 (s, br, 1H), 5.67 (s, br, 1H), 3.97 (d, J ) 1.5 Hz),
3.51 (s, 1H); 13C NMR (CDCl3) δ 170.2, 134.7, 129.1, 128.7, 125.8,
59.0, 58.6; IR (KBr) ν 3380, 3195 (CONH2), 1670, 1643 cm-1 (Cd
O); MS (EI) m/z (%) 163 (16) [M+], 107 (37), 106 (100), 92 (22),
91 (98). Anal. Calcd for C9H9NO2: C, 66.25; H, 5.56; N, 8.58.
Found: C, 65.88; H, 5.47; N, 8.38. When the reaction was
quenched in 27 min, optically active amide 2a [ee 19.5% (chiral
HPLC analysis)] and nitrile 1a [ee 55.1% (chiral HPLC analysis)]
were isolated in 76% and 9% yield, respectively. Biocatalytic
kinetic resolution of (()-2a gave, after 6 h, 2R,3S-(-)-3-phe-
nylglycidamide (2a ) in 43% yield with >99.5% ee (chiral HPLC
analysis). Chemical hydrolysis of optically active nitrile 1a (24
mg, ee 55.1%) under alkaline conditions in the presence of H2O2
(30%) gave 2R,3S-(-)-3-phenylglycidamide (2a ) in 75% yield
with 57.1% ee (chiral HPLC analysis).
(chiral HPLC analysis); 1H NMR (300 MHz, CDCl3, TMS) δ 7.32
(d, J ) 8.4 Hz, 2H), 7.19 (d, J ) 8.4 Hz, 2H), 6.15 (s, br, 1H),
5.60 (s, br, 1H), 3.93 (s, 1H), 3.44 (s, 1H); 13C NMR (CDCl3) δ
167.8, 133.1, 131.4, 127.1, 125.3, 125.2, 56.7, 56.4; IR (KBr) ν
3410, 3245 (CONH2), 1696, 1660 cm-1 (CdO); MS (EI) m/z (%)
199 (7) [M+ + 2], 197 (20) [M+], 142 (34), 140 (99), 127 (25), 125
(79), 91 (26), 89 (100). Anal. Calcd for C9H8ClNO2: C, 54.70; H,
4.08; N, 7.09. Found: C, 54.54; H, 4.27; N, 7.02.
2R,3S-(-)-3-(3-Ch lor op h en yl)glycid a m id e (2f): 80 h; yield
61.2; mp 122-124 °C; [R]25D -52° (c 1.0, CH3OH); ee 31% (chiral
HPLC analysis); 1H NMR (300 MHz, CDCl3, TMS) δ 7.15-7.31
(m, 4H), 6.14 (s, br, 1H), 5.43 (s, br, 1H), 3.93 (d, J ) 1.4 Hz,
1H), 3.45 (s, 1H); 13C NMR (CDCl3) δ 169.9, 136.9, 134.8, 130.0,
129.3, 125.8, 124.1, 58.6, 58.1; IR (KBr) ν 3416, 3172 (CONH2),
1696, 1663 cm-1 (CdO); MS (EI) m/z (%) 199 (12) [M+ + 2], 197
(30) [M+], 142 (26), 140 (68), 127 (18), 125 (62), 91 (41), 89 (100).
Anal. Calcd for C9H8ClNO2: C, 54.70; H, 4.08; N, 7.09. Found:
C, 54.63; H, 4.12; N, 7.04.
cis-(()-3-P h en ylglycid a m id e (4a ): 5 d, yield 73%; 6 d, yield
41%; mp 140-141 °C; [R]25 0° (c 1.0, CH3OH); ee 0% (chiral
D
HPLC analysis); 1H NMR (300 MHz, CDCl3, TMS) δ 7.33-7.36
(m, 5H), 5.78 (s, br, 1H), 5.19 (s, br, 1H), 4.34 (d, J ) 4.8 Hz,
1H), 3.74 (d, J ) 4.8 Hz, 1H); 13C NMR (CDCl3) δ 168.6, 132.7,
128.3, 126.2, 57.0, 56.0; IR (KBr) ν 3410, 3172 (CONH2), 1687,
1663 cm-1 (CdO); MS (EI) m/z (%) 163 (11) [M+], 107 (37), 106
(100), 91 (73), 90 (63). Anal. Calcd for C9H9NO2: C, 66.25; H,
5.56; N, 8.58. Found: C, 66.16; H, 5.54; N, 8.33. Biotransfor-
mation starting from racemic cis-(()-3-phenylglycidamide 4a ,
after 5 d, gave optically inactive 4a in 71% yield.
2R,3S-(-)-3-(4-Meth ylp h en yl)glycid a m id e (2b): 5 h; yield
cis-(()-3-(4-F lu or op h en yl)glycid a m id e (4d ): 6 d; yield
47.2%; mp 190-191 °C; [R]25D -136° (c 0.5, CH3OH) {lit.5c [R]25
44%; mp 142-143 °C; [R]25 0° (c 1.0, CH3OH); ee 0%; 1H NMR
D
D
+158° (c 0.5, CH3OH) 2S,3R-(+)-3-(4-methylphenyl)glycida-
(300 MHz, CDCl3, TMS) δ 7.36 (dd, J ) 8.3, 5.1 Hz, 2H), 7.05 (t,
J ) 8.5 Hz, 2H), 5.80 (s, br, 1H), 5.35 (s, br, 1H), 4.31 (d, J )
4.7 Hz, 1H), 3.77 (d, J ) 4.8 Hz, 1H); 13C NMR (CDCl3) δ 168.4,
164.1, 160.8, 128.6, 128.1, 128.0, 115.5, 57.2, 56.0; IR (KBr) ν
3418, 3289 (CONH2), 1704, 1668 cm-1 (CdO); MS (EI) m/z (%)
181 (10) [M+], 125 (52), 124 (100), 109 (83), 108 (70), 107 (54).
Anal. Calcd for C9H8FNO2: C, 59.67; H, 4.45; N, 7.73. Found:
C, 59.66; H, 4.32; N, 7.49.
Biotr a n sfor m a tion s of a Mixtu r e of Ra cem ic tr a n s- a n d
cis-2,3-Ep oxy-3-(4-ch lor op h en yl)p r op a n en itr iles (2e a n d
4e). Following the general procedure described above, incubation
of a mixture of (()-2a and (()-4a (1 mmol each) with Rhodo-
coccus sp. AJ 270 cells in 14 h gave 2R,3S-(-)-3-(4-chlorophenyl)-
glycidamide (2e) in 21.5% yield with 96.6% ee and cis-(()-2,3-
epoxy-3-(4-chlorophenyl)propanenitrile (4e) in 40.4% yield. The
purity of products 2R,3S-(-)-2e and cis-(()-4e, determined by
1H NMR, was 98% and >99%, respectively.
1
mide}; ee >99.5% (chiral HPLC analysis); H NMR (300 MHz,
CDCl3, TMS) δ 7.15 (s, 4H), 6.20 (s, br, 1H), 5.59 (s, br, 1H),
3.93 (d, J ) 1.8 Hz, 1H), 3.51 (s, 1H), 2.36 (s, 3H); 13C NMR
(CDCl3) δ 170.1, 138.9, 131.5, 129.2, 125.6, 58.8, 58.3, 21.0; IR
(KBr) ν 3400, 3207 (CONH2), 1667 (sh), 1641 cm-1 (CdO); MS
(EI) m/z (%) 177 (29) [M+], 160 (20), 132 (29), 121 (33), 120 (96),
105 (100). Anal. Calcd for C10H11NO2: C, 67.78; H, 6.26; N, 7.90.
Found: C, 67.48; H, 6.00; N, 7.79.
2R,3S-(-)-3-(2-Meth ylp h en yl)glycid a m id e (2c): 24 h; yield
60.0%; mp 181-182 °C; [R]25 -24.5° (c 1.0, CH3OH); ee 39.9%
D
(chiral HPLC analysis); 1H NMR (300 MHz, CDCl3, TMS) δ
7.18-7.27 (m, 4H), 6.26 (s, br, 1H), 5.74 (s, br, 1H), 4.11 (d, J )
1.8 Hz, 1H), 3.42 (s, 1H), 2.44 (s, 3H); 13C NMR (CDCl3) δ 170.3,
136.4, 133.2, 130.1, 128.6, 126.2, 124.2, 57.8, 57.2, 18.8; IR (KBr)
ν 3426, 3158 (CONH2), 1693, 1645 cm-1 (CdO); MS (EI) m/z (%)
177 (38) [M+], 132 (20), 121 (32), 120 (100), 105 (97), 104 (72).
Anal. Calcd for C10H11NO2: C, 67.78; H, 6.26; N, 7.90. Found:
C, 67.81; H, 6.12; N, 8.00.
Ack n ow led gm en t . We thank the State Major
Fundamental Research Program (No. G200077506),
the Ministry of Science and Technology (Grant No.
2002CCA03100), the National Science Foundation of
China, and the Chinese Academy of Sciences for finan-
cial support. M.-X.W. also thanks O. Meth-Cohn and J .
Colby for valuable discussions.
2R,3S-(-)-3-(4-F lu or op h en yl)glycid a m id e (2d ): 6 h; yield
47.3; mp 163-164 °C; [R]25 -140° (c 0.5, CH3OH); ee >99.5%
D
(chiral HPLC analysis); 1H NMR (300 MHz, CDCl3, TMS) δ 7.26
(t, J ) 8.6 Hz, 2H), 7.07 (t, J ) 8.6 Hz, 2H), 6.20 (s, br, 1H),
5.81 (s, br, 1H), 3.96 (d, J ) 1.1 Hz), 3.47 (s, 1H); 13C NMR
(CDCl3) δ 170.0, 164.8, 161.6, 130.5, 127.6, 127.5, 116.0, 115.7,
58.6, 58.4; IR (KBr) ν 3370, 3187 (CONH2), 1669, 1645 cm-1 (Cd
O); MS (EI) m/z (%) 181 (11) [M+], 125 (42), 124 (94), 109 (100),
108 (63). Anal. Calcd for C9H8FNO2: C, 59.67; H, 4.45; N, 7.73.
Found: C, 59.53; H, 4.64; N, 7.75.
Su p p or t in g In for m a t ion Ava ila b le: 1H and 13C NMR
spectra of amides; HPLC analysis of amides. This material is
available free of charge via the Internet at http://pubs.acs.org.
2R,3S-(-)-3-(4-Ch lor op h en yl)glycid a m id e (2e): 10 h; yield
49.0%; mp 190-191 °C; [R]25 -144° (c 0.5, CH3OH); ee >99%
J O0267201
D
J . Org. Chem, Vol. 68, No. 11, 2003 4573