Thiacrown Ether Technology in Lipase-Catalyzed Reaction: Scope and Limitation for Preparing Optically Active 3-Hydroxyalkanenitriles and Application to Insect Pheromone Synthesis

Article abstract of DOI:10.1021/jo971288m

Both reaction rate and enantioselectivity in Pseudomonas cepacia lipase (PCL)-catalyzed hydrolysis of 3-hydroxyalkanenitrile acetates were significantly changed by the addition of catalytic amounts of thiacrown ether (1,4,8,11-tetrathiacyclotetradecane). Although the reaction rate of various nitriles was accelerated, the enantioselectivity greatly depended on the nature of the substrate. Among 10 substrates tested, thiacrown ether offered highest enantioselectivity in PCL-catalyzed hydrolysis of 1-(cyanomehtyl)propyl acetate. Forty or more times this crown ether, molarity based on the enzyme, was required to attain an acceptably high reaction rate and enantioselectivity. Applying this technology, we succeeded in synthesizing the optically pure attractant pheromone of ant Myrmica scabrinodis (A), (R)-3-octanol and its antipode of (S)-isomer in good overall yields.

Full text of DOI:10.1021/jo971288m

J . Org. Chem. 1997, 62, 9165-9172
9165
Th ia cr ow n Eth er Tech n ology in Lip a se-Ca ta lyzed Rea ction : Scop e
a n d Lim ita tion for P r ep a r in g Op tica lly Active
3-Hyd r oxya lk a n en itr iles a n d Ap p lica tion to In sect P h er om on e
Syn th esis
Toshiyuki Itoh,*,† Koichi Mitsukura,† Wipa Kanphai,† Yumiko Takagi,‡ Hiroshi Kihara,‡ and
Hiroshi Tsukube§
Department of Chemistry, Faculty of Education, Okayama University, Okayama 700, J apan,
Department of Natural Science, Hyogo University of Education, Yashiro, Hyogo 673-14, J apan, and
Department of Chemistry, Faculty of Science, Osaka City University, Osaka 558, J apan
Received J uly 15, 1997X
Both reaction rate and enantioselectivity in Pseudomonas cepacia lipase (PCL)-catalyzed hydrolysis
of 3-hydroxyalkanenitrile acetates were significantly changed by the addition of catalytic amounts
of thiacrown ether (1,4,8,11-tetrathiacyclotetradecane). Although the reaction rate of various nitriles
was accelerated, the enantioselectivity greatly depended on the nature of the substrate. Among
10 substrates tested, thiacrown ether offered highest enantioselectivity in PCL-catalyzed hydrolysis
of 1-(cyanomehtyl)propyl acetate. Forty or more times this crown ether, molarity based on the
enzyme, was required to attain an acceptably high reaction rate and enantioselectivity. Applying
this technology, we succeeded in synthesizing the optically pure attractant pheromone of ant
Myrmica scabrinodis (A), (R)-3-octanol and its antipode of (S)-isomer in good overall yields.
In tr od u ction
reaction conditions, modification of substrate,4 selection
of nonaqueous media,2b,5 and use of additive that regu-
lates lipase reactivity.6 Crown ethers are promising
candidates as additives and are known to be complexing
agents for several proteins.7 Reinhoudt et al. reported
that serine proteases were activated by crown ethers,
especially by 18-crown-6.8 We also found that some
crown ethers had the potential to enhance both the
enantioselectivity and reaction rate in the lipase-cata-
lyzed hydrolysis of 2-cyano-1-methylethyl acetate (1a ).1a
In particular, 1,4,8,11-tetrathiacyclotetradecane (4) was
confirmed as the best additive among 35 types of crown
ethers and their acyclic analogues tested.1a To determine
the scope and limitation of this thiacrown ether additive
technology in lipase-catalyzed reaction for preparing
optically active 3-hydroxyalkanenitriles, 10 acetates of
hydroxyalkanenitriles were examined as substrates. We
wish to report here that the enantioselectivity of this
reaction greatly depended on the nature of the substrate
when 5 mol % of thiacrown ether 4 was added. Among
the tested substrates, this thiacrown ether offered the
highest enantioselectivity in the lipase-catalyzed hy-
drolysis of 1-(cyanomethyl)propyl acetate (1b). We ap-
plied this technology in synthesizing the optically pure
attractant pheromone of ant Myrmica scabrinodis (A),
(R)-3-octanol (5).9
Lipases are the most frequently used enzymes in
organic synthesis because of their stability, availability,
and acceptance of a broad range of substrates.2 The
synthetic value of lipases has been well recognized
because their reactions proceed efficiently and selectively
under mild conditions. Since only a limited number of
lipase-catalyzed reactions are applicable for practical
optical resolution, several methods were recommended
to improve their reaction performance:3 optimization of
* To whom correspondence should be addressed. Fax (+81)-86-251-
7639, E-mail address: titoh@cc.okayama-u.ac.jp.
† Okayama University.
‡ Hyogo University of Education.
§ Osaka City University.
X Abstract published in Advance ACS Abstracts, November 15, 1997.
(1) For preliminary accounts for crown ether-modified lipase-
catalyzed reactions, see: (a) Itoh, T.; Takagi, Y.; Murakami, T.;
Hiyama, Y.; Tsukube, H. J . Org. Chem. 1996, 61, 2158. (b) Itoh, T.;
Hiyama, Y.; Betchaku, A.; Tsukube, H. Tetrahedron Lett. 1993, 34,
2617. (c) Takagi, Y.; Teramoto, J .; Kihara, H.; Itoh, T.; Tsukube, H.
Tetrahedron Lett. 1996, 37, 4991. (d) Itoh, T.; Mitsukura, K.; Kaihatsu,
K.; Hamada, H.; Takagi, Y.; Tsukube, H. J . Chem. Soc., Perkin Trans.
1 1997, 2275.
(2) Reviews: (a) Wong C. H.; Whitesides, G. M. In Enzymes in
Synthetic Organic Chemistry; Baldwin, J . E., Magnus, P. D., Eds.;
Tetrahedron Organic Chemistry Series Vol. 12; Pergamon: New York,
1994. (b) Klivanov, A. M. Acc. Chem. Res. 1990, 23, 114. (c) J anssen,
J . M.; Klunder, A. J . H.; Zwanenburg, B. Tetrahedron 1991, 47, 7645.
(d) Nakamura, K.; Hirose, Y. J . Synth. Org. Chem., J pn. 1995, 53, 668.
(e) Theil, F. Chem. Rev. 1995, 95, 2203.
(3) Itoh, T.; Takagi, Y.; Tsukube, H. Trends Org. Chem. 1997, 6, 1.
(4) For example, see: (a) Itoh, T.; Takagi, Y.; Nishiyama, S. J . Org.
Chem. 1991, 56, 1521. (b) Ema, T.; Maeno, S.; Takaya, Y.; Sakai, T.;
Utaka, M. Tetrahedron: Asymm. 1996, 7, 625 and references therein.
(5) Review see: (a) Wescott, C. R.; Klibanov, A. M. Biochim. Biophys.
Acta 1993, 1206, 1. (b) Carrea, G.; Ottolina, G.; Riva, S. Trends
Biotechnol. 1995, 13, 63.
(6) Several types of additives that increase the reactivity of lipases
(dextrometrophan,6a (S)-2-amino-4-(methylthio)-1-butanol,6b sodium
chloride,6c,f calcium chloride,6d potassium chloride,6e Triton X-100,6g and
D-sorbitol6h) were reported to be effective. (a) Guo, Z.-W.; Sih, C. J . J .
Am. Chem. Soc. 1989, 111, 6839. (b) Itoh, T.; Ohira, E.; Takagi, Y.;
Nishiyama, S.; Nakamura, K. Bull. Chem. Soc. J pn. 1991, 64, 624. (c)
Tsukube, H.; Betchaku, A.; Hiyama, Y.; Itoh, T. J . Chem. Soc., Chem.
Commun. 1992, 1751. (d) Holmberg, E.; Holmquist, M.; Hedenstrom,
E.; Berglund, P.; Norin, T.; Hogberg, H.-E.; Hult, K. Appl. Microbiol.
Biotechnol. 1992, 35, 572. (e) Khmelnitsky, Y. L.; Welch, S. H.; Clark,
D. S.; Dordick, J . S. J . Am. Chem. Soc. 1994, 116, 2647. (f) Tsukube,
H.; Hiyama, Y.; Betchaku, A.; Itoh, T. J . Org. Chem. 1994, 59, 7014.
(g) Bhaskar, R. A.; Rehman, H.; Krishnakumari, B.; Yadav, J . S.
Tetrahedron Lett. 1994, 35, 2611. (h) Nagao, Y.; Tohjo, T.; Kaneuchi,
T.; Yukimoto, Y.; Kume, M. Chem. Lett. 1992, 1817.
(7) Odell, B.; Earlam, G. J . Chem. Soc., Chem. Commun. 1985, 359.
(8) (a) Reinhoudt, D. N.; Eondebak, A. M.; Nijenhuis, W. F.;
Verboom, W.; Kloosterman, M.; Schoemaker, H. E. J . Chem. Soc.,
Chem. Commun. 1989 399. (b) Broos, J .; Engbersen, J . F. J .; Sakod-
inskaya, I. K.; Verboom, W.; Reinhoudt, D. N. J . Chem. Soc., Perkin
Trans. 1 1995, 2899. (c) Broos, J .; Martin, M. N.; Rouwenhorst, I.;
Verboom, W.; Reinhoudt, D. N. Recl. Trav. Chim. Pays-Bas 1991, 110,
222. (d) Broos, J .; Verboom, W.; Engbersen, J . F. J .; Reinhoudt, D. N.
Prog. Biotechnol. 8 (Biocatalysis in Non-Conventional Media) 1992,
691. (e) Broos, J .; Kakodinskaya, I. K.; Engbersen, J . F. J .; Verboom,
W.; Reinhoudt, D. N. J . Chem. Soc., Chem. Commun. 1995, 255. (f)
18-Crown-6 enhanced enantioselectivity of R-chymotrypsin-catalyzed
transesterification of N-acetyl-D,L-phenylalanine esters in organic
solvent: Engbersen, J . F. J .; Broos, J .; Verboom, W.; Reinhoudt, D. N.
Pure Appl. Chem. 1996, 68, 2171.
S0022-3263(97)01288-7 CCC: $14.00 © 1997 American Chemical Society

9166 J . Org. Chem., Vol. 62, No. 26, 1997
Ta ble 1. Effect of Th ia cr ow n Eth er 4 on P CL-Ca ta lyzed Hyd r olysis of 1
additive (mol %) time (h) % ee of 2 (% yield) % ee of 3 (% yield) % convn
Itoh et al.
c
entry substrate
R
rate
E value
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
1a
1a
1b
1b
1c
1c
1d
1d
1e
1e
1f
1f
1g
1g
1h
1h
1i
Me
Me
Et
Et
n-Pr
n-Pr
i-Pr
i-Pr
n-Bu
n-Bu
n-Oct
n-Oct
vinyl
vinyl
c-hexyl
c-hexyl
Ph
0
5
0
5
0
5
0
5
0
5
0
5
0
5
0
5
0
5
0
5
60
14
11
8
4.7
4.3
360
168
4.8
3
2
1.8
5.5
3.5
10
12
34.5
78
15.2
11
80 (3.5)
71 (39)
90 (29)
>99 (49)
54 (40)
67 (39)
75 (37)
80 (44)
56 (39)
39 (37)
22 (50)
30 (30)
69 (50)
73 (47)
97 (39)
99 (49)
>99 (49)
>99 (48)
50 (49)
40 (42)
16 (40)
99 (40)
86 (29)
94 (35)
43 (41)
52 (37)
59 (42)
62 (51)
37 (49)
39 (43)
26 (29)
20 (29)
60 (41)
67 (49)
76 (61)
82 (51)
75 (47)
>99 (50)
34 (41)
35 (46)
38
59
49
49
44
44
44
44
40
50
54
40
47
48
44
45
43
50
40
47
0.6
4.2
4.5
6
9.4
10.2
0.1
0.3
8.3
13.9
27
27.8
8.5
14.3
4.4
3.8
1.3
0.6
2.6
4.3
16
37
53
>700
5
8
13
17
5
3
2
2
10
13
152
501
449
>1057
4
1i
1j
1j
Ph
PhCH2CH2
PhCH2CH2
3
a
b
Optical purity of the product shows >99% ee when no isomer was detected by GLC analysis. Rate shows percent conversion per
reaction time (h).
Resu lts a n d Discu ssion
aqueous lipase solution was added to a solution of (()-1
(1.25 mmol), together with a crown ether 4 additive (5
mol % toward the substrate) in 1.25 mL of acetone. The
resulting mixture was stirred at 35 °C, and the reaction
was stopped when the mole ratio of acetate 1 and alcohol
2 became equal. The alcohol (R)-2 produced and remain-
ing ester (S)-1 were extracted with ethyl acetate and
separated by silica gel TLC (hexane/ethyl acetate ) 2:1).
The enantiomeric excess of the remaining acetate (S)-1
was determined by capillary GLC analysis using chiral
stationary phase (Chiraldex G-Ta). The enantiomeric
excess of alcohol (R)-2 was also determined by the GLC
analysis of the corresponding acetate. Because this
reaction is a kinetic resolution of the racemic substrate,
the optical purity of the producing alcohol and remaining
acetate depends on the reaction conversion. The effect
of this crown ether on enantioselectivity was evaluated
by comparison of E values, which were calculated by the
equation proposed by Sih.12 The relative rate was
calculated from the percentage conversion per reaction
time. These results obtained for the reaction at 35 °C
are summarized in Table 1, and Figure 1a,b.
There were marked differences of the additive effect
on the enantioselectivity among the substrates employed
(Figure 1a), while thiacrown ether only slightly influ-
enced the reaction rate (Figure 1b). The most significant
enhancement in enantioselectivity was observed when
the reaction was carried out using 1-(cyanomethyl)propyl
acetate (1b: R ) Et) as the substrate (Table 1, entry 4).
Although the hydrolysis of 1b proceeded with modest
enantioselectivity (E ) 53) without the additive (Table
1, entry 3), the addition of 5 mol % thiacrown ether 4 to
the substrate significantly enhanced enantioselectivity,
reaching a higher level for practical use (E ) 700) (Table
1, entry 4). The enantioselectivities of the reactions of
1h and 1i were similarly enhanced about two to three
times by the addition of thiacrown 4 (Table 1, entries 15-
Effect of Th ia cr ow n Eth er Ad d itive on P CL-
Catalyzed Hydr olysis of Var iou s 3-Hydr oxyalkan en -
itr iles. We chose acetates 1 as model substrates and
PCL as the enzyme because 3-hydroxyalkanenitriles are
employable chiral building blocks and PCL is applicable
to various substrates.10 Racemic 3-hydroxyalkaneni-
triles, (()-2, were prepared through two different path-
ways, the first one being the reaction of potassium
cyanide with oxiranes.1a,11 Three types of 3-hydroxyal-
kanenitriles, 2a ,1a 2b, and 2e, were thus prepared in 54-
74% yield.5 This method is very convenient for preparing
the corresponding 3-hydroxyalkanenitriles from oxiranes,
though limited types of oxiranes are commercially avail-
able. The second method is nucleophilic addition of
lithioacetonitrile to aldehydes.4a Seven types of acetates,
1c,d ,f-j, were prepared through this path, though the
reaction required expensive butyllithium as a lithiation
reagent and should be carried out very carefully under
argon atmosphere. The alcohols obtained were converted
to the corresponding acetates 1b-j in almost quantitative
yields by treatment with acetyl chloride in the presence
of pyridine as base.
The hydrolysis of (()-1 was carried out in a nonbuf-
fered aqueous solution to exclude any effect of complex-
ation between this thiacrown ether 4 and metal cation
(eq 1). When 2-cyano-1-methylethyl acetate (1a ) was
(9) (a) Fujiwhara, M.; Mori, K. Agric. Biol. Chem. 1986, 50, 2925.
(b) Cammaerts, M.-C.; Mori, K. Physiol. Entomol. 1987, 12, 381.
(10) Weissfloch, A. N. E.; Kazlauskas, R. J . J . Org. Chem., 1995,
60, 6959.
(11) Comai, K.; Sullivan, A. C. J . Pharm. Sci. 1982, 71, 418.
(12) Chen, C.-S.; Fujimoto, Y.; Girdauskas, G.; Sih, C. J . J . Am.
Chem. Soc. 1982, 102, 7294. Chen, C.-S.; Wu, S.-H.; Girdauskas, G.;
Sih, C. J . J . Am. Chem. Soc. 1987, 109, 2812.
employed as substrate, the optimum value was obtained
in the presence of 5 and 33 mol % of the thiacrown ether
to the substrate.1a Therefore, we decided to use 5 mol %
of thiacrown ether toward the substrate. The reaction
was typically carried out as follows: 12.5 mL of an

Thiacrown Ether Technology
J . Org. Chem., Vol. 62, No. 26, 1997 9167
magnitude of increase at each temperature. It is quite
interesting that the hydrolysis proceeded even at 0 °C
and reached 27% conversion after 24 h in the presence
of thiacrown ether 4, though the hydrolysis conversion
of 24 h reaction was only 3% in the absence of the crown
ether (Figure 2a).
We performed these reactions in nonbuffered aqueous
media; the reaction rate gradually lowered in the reaction
course and E values obtained were greatly reduced at
over 40% conversion.1a This seems to be a result of
inactivation of enzyme by lower pH or a reverse reaction.
Figure 3 show results of the hydrolysis of acetate (()-1b
in the presence and absence of thiacrown ether 4 at 35
°C; pH values of both of the solutions reached 3.4-3.5
after 20 h because the reactions were carried out under
conditions of no pH control. The reaction was dramati-
cally accelerated by the crown ether additive as shown
in Figure 3. The hydrolysis did not stop after 30 h when
5 mol % of 4 was present, while the reaction stopped after
25 h in the absence of thiacrown ether 4. It should be
emphasized that the enzymatic reaction proceeded in the
pH range of 3.4-3.5 in the presence of thiacrown ether
4. Addition of thiacrown ether clearly had an impact on
the lipase activity.
Why does the crown ether modify lipase performance?
Crown ethers bind metal cations with varying strength
depending on structural variations. The lipase solution
employed was confirmed to contain the following alkali
and alkaline earth metal cations: Na+, 6.5 × 10-4 mol/
L; K+, 4.6 × 10-4 mol/L; Mg2+, 6 × 10-4 mol/L; and Ca2+
,
6.3 × 10-4 mol/L.1a The amounts are believed to be too
small to affect the enzyme reactivity, and it is well-known
that thiacrown ether does not possess strong affinity with
these alkali metal cations.13 Some metal salts were
recently reported to influence the catalytic activities of
enzymes,6c-f but in that case crown ether-metal cation
complexation may not be involved. Recently, Reinhoudt
and his colleagues reported that 18-crown-6 activated
some enzymes; in that case, 18-crown-6 might modify the
conformation of the enzyme by trapping water molecules
at the active site or the enzyme surface.8f
We have proposed the following mechanism for en-
hanced enantioselectivity by thiacrown ether additive:1a
when lipophilic thiacrown ethers remain at the entrance
of the lipase, they may modify the local conformation of
the lipase; this increases fitness of the substrate intro-
duced to the active site of the enzyme, traps the product
alcohol, and accelerates the diffusion of the alcohol into
the bulk water phase. 13C NMR binding experiments
support the possibility that thiacrown ether can trap the
alcohol. When thiacrown ether 4 was added to a CDCl3
solution of the product alcohols, 2b and 2f, large 13C NMR
spectral changes were observed at the carbon signals at
the 3-position of both products (Figure 4), while no
significant induced chemical shift change was observed
for substrate 1b or 1f (Table 2). An induced chemical
shift of nitrile carbon for 2f was -0.24 ppm, while no
significant induced chemical shift was observed for that
of 2b (∆δ ) +0.002 ppm). These results may suggest
that nitriles 2b and 2f interact with thiacrown ether in
different fashions. Because the enzymatic reaction was
performed in water, a 13C NMR experiment was also
carried out in D2O. Due to the low solubility of the
thiacrown ether 4 in D2O, however, no spectral change
F igu r e 1. (a) Enantioselectivity of PCL-catalyzed hydrolysis
of various acetates 1 in the presence of 5 mol % of thiacrown
ether 4. (b) Relative rate change of PCL-catalyzed hydrolysis
of various acetates 1 in the presence of 5 mol % of thiacrown
ether 4.
18). On the contrary, no marked enhancement in enan-
tioselectivity was observed when acetates 1e (R ) n-Bu),
1f (R ) n-Oct), and 1j (R ) phenethyl) were used (Table
1, entries 9-12, 19, and 20). With substrates 1a ,d ,g, the
enantioselectivity was slightly enhanced (Figure 1a).
These results obviously suggest that this crown ether
additive cannot change the original stereochemistry of
the product but does enhance its potential ability to a
level at which the reaction can be used practically.
Figure 2a, shows the results of the hydrolysis of acetate
1a under different temperature conditions. The addition
of only 5 mol % of thiacrown ether accelerated the
hydrolysis rate of both enantiomers with a similar
(13) Izatt, R. M.; Pawlak, K.; Bradshaw, J . S.; Bruening, R. L. Chem.
Rev. 1991, 91, 1721.

9168 J . Org. Chem., Vol. 62, No. 26, 1997
Itoh et al.
F igu r e 2. (a) Reaction course of the hydrolysis of (R)-1a in the presence of thiacrown ether 4. (b) Reaction course of the hydrolysis
of (S)-1a in the presence of thiacrown ether 4.
was detected in the 13C NMR signal of the monoacetate.
To confirm this hypothesis, the conformational change
of the enzyme by thiacrown ether should be investigated,
though the change may be too small to be seen using the
present analytical instrument. It has been reported that
the conformational change in the protein is reflected in
the CD spectra.14 However, we have observed no sig-
nificant spectral change when the CD spectra of the PCL
aqueous solution were measured in the presence of 5-33
mol % of thiacrown ether 4. Although we have not yet
elucidated the mechanism of this enhancement com-
pletely, these results provided interesting application in
organic synthesis, especially for the synthesis of chiral
natural products.
highly efficient optical resolution of racemic 1b; this
provided 3-hydroxypentanenitrile 2b in optically pure
form (>99% ee). Applying this, the facile synthesis of
the attractive pheromone of the ant M. scabrinodis (A)
was accomplished using (R)-2b as a starting material
(Scheme 1).
An aqueous lipase solution (100 mL, including ca. 700
mg of PCL) was added to a solution of (()-1b (1.41 g,
9.99 mmol), together with thiacrown ether 4 (5 mol %
toward the substrate) in 10 mL of acetone. The resulting
mixture was stirred at 35 °C, and the reaction was
stopped when ester and alcohol became equal-to-mole
ratio by gas chromatography analysis. Alcohol (R)-2b
produced and ester (S)-1b remaining were extracted with
ethyl acetate and separated by silica gel flash column
chromatography (hexane/ethyl acetate 2:1); this gave (R)-
2b (4.94 mmol, 49%) and (S)-1b (4.55 mmol, 46%). The
enantiomeric excess of these compounds was confirmed
as >99% ee by GLC analysis using chiral capillary
Syn th esis of a n Attr a cta n t P h er om on e of th e An t
M. sca br in od is. We described above that thiacrown
ether technology in the PCL-catalyzed reaction led to the
(14) Colton, I. J .; Sharmin, N. A.; Kazlauskas, R. J . J . Org. Chem.
1995, 60, 212.

Thiacrown Ether Technology
J . Org. Chem., Vol. 62, No. 26, 1997 9169
Sch em e 1. Syn th esis of th e Attr a cta n t P h er om on e
of An t Myr m ica sca br in od is (A)
Exp er im en ta l Section
Ma ter ia ls. Crown ethers were purchased from Aldrich and
used without further purification. P. cepacia lipase was
provided by Amano Pharmaceutical Co., Ltd. (J apan).
3-Hyd r oxyp en ta n en itr ile (2b). To a solution of 1,2-
epoxybutane (10.8 g, 150 mmol) in ethanol (22 mL) under
argon atmosphere at 50-60 °C was added 32% KCN aqueous
solution (150 mmol, 21 mL) and 30% CH3CO2H aqueous
solution (150 mmol, 21 mL) dropwise at the same time. The
mixture was stirred for 3 h, keeping the pH value at around
7. After being cooled to room temperature, the mixture was
extracted with Et2O. The combined organic layers were dried
over MgSO4, filtered, and evaporated. Kugelrohr distillation
afforded 2b (11.0 g, 111.0 mmol) as a colorless oil in 74%
yield: Rf 0.29 (hexane/ethyl acetate 2:1); bp 145 °C/45 Torr
(Kugelrohr); 1H NMR (200 MHz, δ, CDCl3, J ) Hz), 0.95 (3H,
t, J ) 7.4), 1.59 (2H, dq, J ) 7.5, 7.4), 2.51 (2H, dd, J ) 17.0,
5.3), 2.90 (1H, s, OH), 3.8-3.9 (1H, m); 13C NMR (50 MHz,
ppm, CDCl3, J ) Hz) 9.56, 25.51, 29.33, 68.81, 117.87; IR (neat,
cm-1) 3400, 2900, 2250, 1460, 1405, 1105, 980. Anal. Calcd
for C5H9NO: C, 60.58; H, 9.15; N, 14.13. Found: C, 60.39; H,
9.38; N, 13.28.
F igu r e 3. pH response of PCL-catalyzed hydrolysis of (()-
1b in the presence of 5 mol % of thiacrown ether 4.
F igu r e 4. Induced 13C NMR (50 MHz) spectral change. The
values ∆δ (ppm) mean differences in 13C NMR chemical shifts
in the absence and in the presence of 2.0 equiv of thiacrown
ether 4 in 0.05 M CDCl3.
(R)-2b (>99% ee): [R]25D -0.8 (c 1.51, CHCl3) (S)-2b (>99%
ee): [R]25 +1.6 (c 0.66, CHCl3). Using the same procedure,
D
γ-hydroxyheptanenitrile 2e was also prepared from the cor-
responding epoxide.
Ca u tion : P ota ssiu m cya n id e is ver y toxic so th a t th e
r ea ction m u st be ca r r ied ou t in a w ell-ven tila ted a r ea .
3-Hyd r oxyh ep ta n en itr ile (2e): Rf 0.17 (hexane/ethyl
acetate 4:1); bp 160 °C/43 Torr (Kugelrohr); 1H NMR (200
MHz, δ, CDCl3, J ) Hz) 0.93 (3H, t, J ) 7.1), 1.36-1.59 (4H,
m), 2.45 (1H, dd, J ) 16.6, 6.4), 2.56 (1H, dd, J ) 16.6, 4.9)
2.84 (1H, brs, OH), 3.93 (1H, dt, J ) 17.4, 5.8); 13C NMR(50
MHz, ppm, CDCl3) 13.64, 18.51, 25.98, 38.45, 67.27, 117.83;
IR (neat, cm-1) 3440, 2950, 2240, 1460, 1415, 1120, 1015.
Anal. Calcd for C7H13NO: C, 66.11; H, 10.30; N, 11.01.
Found: C, 65.91; H, 10.32; N, 11.00.
3-Hyd r oxy-4-p en ten en itr ile (2 g). To a solution of di-
isopropylamine (3.04 g, 30.04 mmol) in THF (30 mL) under
argon atmosphere at -10 °C was added a solution of n-BuLi
in hexane (1.62 M, 17.0 mL, 27.54 mmol). The mixture was
stirred at 10 °C for 1 h and cooled to -78 °C, and then a
solution of CH3CN (1.23 g, 29.96 mmol) in THF (15 mL) was
added. The mixture was stirred at -78 °C for 1 h, a solution
of propionaldehyde (1.40 g, 24.97 mmol) in THF (15 mL) was
added, and the mixture was again stirred at -78 °C for 3 h.
The reaction was quenched with saturated aqueous NH4Cl and
treated with aqueous 2 M HCl. The mixture was extracted
with Et2O, and the combined organic layers were dried over
MgSO4, filtered, and evaporated. The obtained yellow oily
residue was purified by flash column chromatography (gradi-
ent elution hexane/ethyl acetate 8:1-4:1) to give an alcohol
2g as a colorless oil (2.23 g, 23.0 mmol) in 92% yield: Rf 0.27
(hexane/ethyl acetate 2:1); bp 150 °C/42 Torr (Kugelrohr); 1H
NMR (200 MHz, δ, CDCl3, J ) Hz) 2.58 (2H, dd, J ) 16.7,
5.9), 3.03 (1H, brs, OH), 4.43 (1H, dt, J ) 16.4, 5.3), 5.26 (1H,
dt, J ) 10.4, 1.3), 5.37 (1H, dt, J ) 16.4, 1.3), 5.89 (1H, ddd,
J ) 16.4, 10.4, 5.9); 13C NMR (50 MHz, ppm, CDCl3) 25.87,
column. (R)-2b was converted to tert-butyldimethylsilyl
ether (R)-6b in 97% yield. Carbon elongation of (R)-6b
was successfully achieved through the Wittig reaction15
protocol; (R)-6b was treated with diisobutylalminum
hydride (DIBAL) at -78 °C giving the corresponding
aldehyde 7, which was used without isolation for subse-
quent Wittig reaction; silyl ether (R)-8 was thus obtained
in 77% overall yield from (R)-2b. Finally, hydrogenation
of (R)-8 released the target molecule (R)-5 ([R]23 -9.5°
D
(c 0.96, CHCl3), lit.9a [R23 -9.7°), the attractant phero-
D
mone of the ant M. scabrinodis (A), in 88% yield (66%
overall yield from (R)-2b). The antipode of this phero-
mone, (S)-5, was also synthesized from (S)-1b through
the same reaction sequences in 51% overall yield.
It should be emphasized that the key step of this
synthesis is a pollution-free chemical reaction using a
natural enzymatic system. Lipase-catalyzed reactions
are particularly useful even for large-scale preparative
organic synthesis. In particular, Pseudomonas cepacia
lipase is commercially available and not very expensive;
hence, the present protocol can undoubtedly allow us to
evolve a smarter and more convenient synthesis of
pheromone compounds.
(15) Wittig, G. Angew. Chem. 1956, 68, 505.

9170 J . Org. Chem., Vol. 62, No. 26, 1997
Itoh et al.
Ta ble 2. Ch em ica l Sh ift Ch a n ges of 50 MHz 13C NMR Sp ectr a (in 0.05 M CDCl3) of 1b,f, a n d 2b,f in th e P r esen ce of
Th ia cr ow n Eth er 4 (2 Mol Equ iv)
compd
amt of 4 (equiv)
C5 (ppm)
C7 (ppm)
C4 (ppm)
C2 (ppm)
C3 (ppm)
C1 (CN) (ppm)
C6 (CO) (ppm)
1b (OAc)
1b (OAc)
0.00
2.0
9.26
9.35
20.76
20.85
22.34
22.42
26.18
26.24
69.78
69.84
116.23
116.23
170.19
170.27
∆ δ
+0.09
+0.09
+0.08
+0.06
+0.06
(0.00
+0.08
2b (OH)
2b (OH)
0.00
2
9.57
9.61
25.50
25.64
29.33
29.50
68.81
69.09
117.86
117.88
∆ δ
+0.04
+0.14
+0.17
+0.28
+0.02
1f (OAc)
1f (OAc)
0.00
2.0
14.02
14.02
20.85
20.88
22.81
22.84
33.08
33.11
68.66
68.69
116.29
116.27
170.24
170.26
∆ δ
0.00
2.0
(0.00
14.01
14.03
+0.02
0.03
0.03
25.31
25.32
+0.01
0.03
36.44
36.54
+0.10
0.03
67.64
67.81
+0.17
-0.02
117.79
117.55
-0.24
0.02
2f (OH)
2f (OH)
∆ δ
68.34, 117.26, 68.81, 117.40, 137.21; IR (neat, cm-1) 3410, 2880,
2240, 1640, 1410, 1120, 930. Anal. Calcd for C5H7NO: C,
61.84; H, 7.27; N, 14.42. Found: C, 61.77; H, 7.34; N, 14.24.
Using the same procedure, hydoxyalkanenitriles 2c-jwere
also prepared from the corresponding aldehydes.
3-Hyd r oxyh exa n en itr ile (2c): Rf 0.27 (hexane/ethyl
acetate 3:1); bp 108 °C/2 Torr (Kugelrohr); 1H NMR (200 MHz,
δ, CDCl3, J ) Hz) 0.89 (3H, t, J ) 6.9), 1.29-1.36 (4H, m),
1.51-1.58 (2H, m), 2.50 (2H, dd, J ) 16.7, 4.9), 2.81 (1H, brs,
OH), 3.90 (1H, m); 13C NMR (50 MHz, ppm, CDCl3) 13.81,
22.29, 25.95, 27.39, 36.06, 67.51, 117.86; IR (neat, cm-1) 3420,
2925, 2240, 1465, 1410, 1120, 1020. Anal. Calcd for
C6H11NO: C, 63.69; H, 9.80; N, 12.38. Found: C, 63.30; H,
9.81; N, 11.98.
3-Hyd r oxy-4-m eth ylp en ta n en itr ile (2d ): Rf 0.40 (hex-
ane/ethyl acetate 2:1); bp 115 °C/4 Torr (Kugelrohr); 1H NMR
(200 MHz, δ, CDCl3, J ) Hz) 0.94 (6H, t, J ) 6.5, 6.3), 1.79
(1H, dq, J ) 13.3, 6.7), 2.50 (1H, d, J ) 3.1), 2.53 (1H, d, J )
1.4), 2.63-2.77 (1H, brs, OH), 3.63-3.71 (1H, m); 13C NMR
(50 MHz, ppm, CDCl3) 17.24, 18.40, 23.52, 33.16, 72.42, 118.28;
IR (neat, cm-1) 3460, 2970, 2250, 1470, 1420, 1130, 1060.
Anal. Calcd for C6H11NO: C, 63.69; H, 9.80; N, 12.38.
Found: C, 63.81; H, 10.35; N, 12.40.
3-Hyd r oxyu n d eca n en itr ile (2f): Rf 0.25 (hexane/ethyl
acetate 4:1); bp 150 °C/3.5 Torr (Kugelrohr); 1H NMR (200
MHz, δ, CDCl3, J ) Hz) 0.86 (3H, t, J ) 6.5), 1.23 (12H, s),
1.55 (2H, t, J ) 6.4), 2.51 (2H, m), 2.78 (1H, brs, OH), 3.8-4.0
(1H, m); 13C NMR (50 MHz, ppm, CDCl3) 14.01, 22.57, 25.31,
26.01, 29.12, 29.25, 29.36, 31.74, 36.45, 67.64, 117.79; IR (neat,
cm-1) 3420, 2920, 2240, 1460, 1410, 1120, 1075. Anal. Calcd
for C11H21NO: C, 72.08; H, 11.55; N, 7.64. Found: C, 73.91;
H, 11.64; N, 7.23.
(200 MHz, δ, CDCl3, J ) Hz) 2.50-2.53 (1H, brs, OH), 2.74
(2H, d, J ) 6.2), 5.02 (1H, t, J ) 6.2), 7.38 (5H, s); 13C NMR
(50 MHz, ppm, CDCl3, J ) Hz) 27.88, 70.02, 117.29, 125.48,
128.78, 128.88, 140.97; IR (neat, cm-1) 3440, 2900, 2250, 1500,
1450, 1060, 760, 700.
3-Hyd r oxy-5-p h en ylp en ta n en itr ile (2j):4a Rf 0.29 (hex-
ane/ethyl acetate 2:1); bp 172 °C/2.5 Torr (Kugelrohr); 1H NMR
(200 MHz, δ, CDCl3, J ) Hz) 1.83-1.95 (2H, m), 2.48-2.62
(3H, m), 2.65-2.82 (2H, m), 3.93 (1H, dt, J ) 13.2, 5.7), 7.17-
7.34 (5H, m); 13C NMR (50 MHz, ppm, CDCl3) 26.21, 31.52,
37.85, 66.82, 117.65, 126.17, 128.32, 128.54, 140.67; IR (neat,
cm-1) 3420, 2910, 2240, 1590, 1490, 1450, 1410, 1050, 750, 700.
1-(Cya n om eth yl)p r op -2-en yl a ceta te (1g). To 3-hy-
droxy-4-pentenenitrile (2g) solution (963 mg, 9.92 mmol) in
CH2Cl2 (20 mL) and pyridine (1.0 mL) was added a CH2Cl2
solution (20 mL) of acetyl chloride (1.56 g, 19.9 mmol) at 0 °C,
and the solution was stirred at room temperature for 3 h. The
reaction was quenched by the addition of crushed ice, extracted
with CH2Cl2, dried over MgSO4, and evaporated. The crude
product was purified by flash column chromatography (hexane/
ethyl acetate 10:1) to provide acetate 2g (1.24 g, 8.91 mmol)
in 90% yield: Rf 0.53 (hexane/ethyl acetate 2:1); bp 155 °C/45
Torr (Kugelrohr); 1H NMR (200 MHz, δ, CDCl3, J ) Hz) 0.93
(3H, t, J ) 7.4), 1.6-1.9 (2H, m), 2.07 (3H, s), 2.57 (2H, dd, J
) 17.2, 5.4), 2.63 (2H, dd, J ) 17.2, 5.4), 4.8-5.0 (1H, m); 13
C
NMR (50 MHz, ppm, CDCl3) 9.27, 20.76, 22.34, 26.18, 69.78,
116.23; IR (neat, cm-1) 2950, 2200, 2250, 1720, 1220, 1050.
Anal. Calcd for C7H9NO2: C, 60.42; H, 6.52; N, 10.07.
Found: C, 60.36; H, 6.59; N, 9.91.
Using the same procedure, 1-alkyl-2-cyano acetates 1b-j
were also prepared from the corresponding hydoxyalkaneni-
triles.
3-Hyd r oxy-3-cycloh exylp r op a n en itr ile (2h ): Rf 0.54
(hexane/ethyl acetate 2:1); bp 156 °C/2.8 Torr (Kugelrohr); 1H
NMR (200 MHz, δ, CDCl3, J ) Hz) 0.88-1.33 (4H, m), 1.37-
1.58 (1H, m), 1.58-1.95 (6H, m), 2.43 (1H, s, OH), 2.48 (1H,
dd, J ) 16.9, 6.9), 2.58 (1H, dd, J ) 16.9, 4.9), 3.62-3.71 (1H,
m); 13C NMR (50 MHz, ppm, CDCl3) 23.51, 25.61, 25.77, 26.03,
27.77, 28.81, 42.74, 71.83, 118.24; IR (neat, cm-1) 3455, 2925,
2250, 1450, 1060, 1040. Anal. Calcd for C9H15NO: C, 70.55;
H, 9.87; N, 9.14. Found: C, 70.70; H, 10.07; N, 9.05.
3-Hyd r oxy-3-p h en ylp r op a n en itr ile (2i):4a Rf 0.32 (hex-
ane/ethyl acetate 2:1); bp 161 °C/2 Torr (Kugelrohr); 1H NMR
1-(Cya n om eth yl)p r op yl a ceta te (1b): Rf 0.53 (hexane/
ethyl acetate 2:1); bp 155 °C/45 Torr (Kugelrohr); 1H NMR (200
MHz, δ, CDCl3, J ) Hz) 0.93 (3H, t, J ) 7.4), 1.6-1.9 (2H, m),
2.07 (3H, s), 2.57 (1H, dd, J ) 17.2, 5.4), 2.63 (1H, dd, J )
17.2, 5.4), 4.8-5.0 (1H, m); 13C NMR (50 MHz, ppm, CDCl3)
9.27, 20.76, 22.34, 26.18, 69.78, 116.23, 170.19; IR (neat, cm-1
)
2950, 2200, 1720, 1220, 1050. Anal. Calcd for C7H11NO2: C,
59.56; H, 7.85; N, 9.92. Found: C, 58.89; H, 8.14; N, 9.87.
(R)-1b (>99% ee): [R]25 +79.2 (c 1.765, CHCl3).
D
(S)-1b (>99% ee): [R]25 -80.0 (c 1.050, CHCl3).
D

Thiacrown Ether Technology
J . Org. Chem., Vol. 62, No. 26, 1997 9171
Ta ble 3. Resu lts of GLC An a lysis a n d [r]D Va lu es of Aceta tes 1
compd
R
[R]D (c in CHCl3)
GLC tR
GLC k
GLC R
GLC column temp (°C)
(R)-1a
(S)-1a
(R)-1b
(S)-1b
(R)-1c
(S)-1c
(R)-1d
(S)-1d
(R)-1e
(S)-1e
(R)-1f
(S)-1f
(R)-1g
(S)-1g
(R)-1h
(S)-1h
(R)-1i
(S)-1i
(R)-1j
(S)-1j
Me
Me
Et
Et
n-Pr
n-Pr
i-Pr
i-Pr
n-Bu
n-Bu
n-Oct
n-Oct
vinyl
vinyl
c-Hex
c-Hex
Ph
[R]25 +48.9 (c 1.15), 91% ee
5.2
9.4
7.3
1.1
2.8
2.7
4.6
4.3
6.6
4.1
8.5
7.6
11.7
12.4
16.5
2.1
3.2
5.5
7.3
6.9
7.6
7.4
8.5
100
100
100
100
100
100
100
100
100
100
130
130
100
100
130
130
130
130
150
150
D
[R]25 -51.4 (c 1.23), 94% ee
2.5
1.8
1.6
2.1
1.5
1.3
1.5
1.3
1.1
1.1
D
[R]21 +66.0 (c 1.81), >99% ee
D
[R]21 -67.3 (c 1.76), 94% ee
11.2
10.5
15.3
10.3
19.0
17.2
25.4
26.7
35.1
6.3
D
[R]23 +24.8 (c 1.26), 67% ee
D
[R]23 -25.6 (c 0.90), 52% ee
D
[R]22 -52.2 (c 0.76), 79 % ee
D
[R]23 +42.7 (c 0.83), 62 % ee
D
[R]16 +20.9 (c 0.69), 39 % ee
D
[R]16 -17.2 (c 0.85), 39 % ee
D
[R]23 +9.6 (c 1.62), 30 % ee
D
[R]23 -2.3 (c 1.65), 20 % ee
D
[R]23 -8.3 (c 0.99), 73 % ee
D
[R]23 +14.2 (c 1.03), 67 % ee
8.3
D
[R]23 -31.4 (c 0.52), 99 % ee
13.6
16.6
15.8
17.2
16.8
19.0
D
[R]23 +33.33 (c 0.74), 82% ee
D
[R]23 -67.3 (c 0.65), >99% ee
D
Ph
[R]23 +72.8 (c 0.64), >99% ee
D
PhCH2CH2
PhCH2CH2
[R]23 -7.7 (c 0.81), 50% ee
D
[R]23 +17.9 (c 1.03), 34% ee
D
a
GLC analysis for determination of % ee of (()-1 was carried out using a capillary column on chiral phase; Chiraldex G-TA (L 0.25 ×
20 M).
1-(Cya n om eth yl)bu tyl a ceta te (1c): Rf 0.41 (hexane/
25.49, 70.39, 115.98, 126.06, 128.89, 128.99, 137.11, 169.55;
IR (neat, cm-1) 2940, 2250, 1740, 1490, 1450, 1240, 1050, 760,
710.
ethyl acetate 2:1); bp 172 °C/43 Torr (Kugelrohr); 1H NMR (200
MHz, δ, CDCl3, J ) Hz) 0.92 (3H, t, J ) 7.2), 1.31-1.67 (2H,
m), 1.58-1.72 (2H, m), 2.06 (3H, s), 2.56 (1H, dd, J ) 16.8,
1-(Cya n om eth yl)-3-p h en ylp r op yl a ceta te (1j):4a Rf 0.54
(hexane/ethyl acetate 2:1); bp 182 °C/2.8 Torr (Kugelrohr); 1H
NMR (200 MHz, δ, CDCl3, J ) Hz) 1.98-2.05 (2H, m), 2.08
(3H, s), 2.66 (4H, ddd, J ) 31.8, 17.0, 5.1), 5.00 (1H, dt, J )
13.5, 5.0), 7.14-7.33 (5H, m); 13C NMR (50 MHz, ppm, CDCl3,
J ) Hz) 20.78, 22.90, 31.30, 34.59, 68.04, 116.12, 126.28,
128.20, 128.54, 140.04, 170.19; IR (neat, cm-1) 2920, 2240,
1740, 1600, 1490, 1450, 1230, 1040, 750, 710.
5.4), 2.70 (1H, dd, J ) 16.8, 5.4), 4.96 (1H, tt, J ) 5.0, 4.9); 13
C
NMR (50 MHz, ppm, CDCl3) 13.49, 18.24, 20.78, 22.78, 35.09,
68.33, 116.27, 170.18; IR (neat, cm-1) 2950, 2240, 1740, 1225,
1025. Anal. Calcd for C8H13NO2: C, 61.91; H, 8.44; N, 9.03.
Found: C, 61.21; H, 8.48; N, 8.98.
1-(Cya n om eth yl)-2-m eth ylp r op yl a ceta te (1d ): Rf 0.39
(hexane/ethyl acetate 4:1); bp 122 °C/ 3.5 Torr (Kugelrohr);
1H NMR (200 MHz, δ, CDCl3, J ) Hz) 0.95 (6H, d, J ) 6.9),
2.03 (1H, dq, J ) 13.6, 6.8), 2.10 (3H, s), 2.59 (1H, dd, J )
Lip a se-Ca t a lyzed Hyd r olysis. A typical example is
described below: To an acetone solution (10 mL) of ester (()-
1b (1.41 g, 10.0 mmol) and thiacrown ether 4 (134 mg, 0.5
mmol) was added lipase PS aqueous solution (100 mL), and
the resulting mixture was incubated at 35 °C. The progress
of the reaction was monitored by GLC analysis using Quadlex
MS (L 0.25 × 25 M). The reaction was stopped by the addition
of small pieces of ice, and then the mixture was extracted with
ethyl acetate, dried over MgSO4, and evaporated to dryness.
The product 2b and remaining substrate (-)-1b were sepa-
rated by silica gel TLC (hexane/ethyl acetate 2:1). The lipase
solution was prepared in the following way: A boltex shaking
suspension of lipase PS (705 mg) in deionized water (110 mL)
was centrifuged at 3000 rpm for 5 min at room temperature,
and then 100 mL of the supernatant was immediately used
as the enzyme solution. GLC analysis for determination of %
ee of (()-1b was carried out using a capillary column on chiral
phase; Chiraldex G-TA, L 0.25 mm × 20 m; carrier gas, He
40 mL/min; T (°C) 100 or 130; inlet pressure 1.35 kg/cm2;
amount 400 ng; detection FID. The results of GLC analyses
of racemic 1a -h are summarized in Table 3.
Th e Attr a ctive P h er om on e of th e An t M. sca br in od is
(A): (R)-3-Octa n ol (5).9 To a solution of (R)-1b (1.03 g, 10.4
mmol, >99% ee) in dry DMF (20 mL) was added a DMF (15
mL) solution of tert-butyldimethylsilyl chloride (2.74 g, 19.2
mmol) and imidazole (1.23 g, 18.1 mmol) in DMF (5 mL) at 0
°C. After the mixture was stirred for 5 h at room temperature,
the reaction was quenched by crushed ice and extracted with
ether. The organic layer was washed with water, dried over
anhydrous MgSO4, and evaporated to dryness. Silica gel
column chromatography (hexanes-ethyl acetate ) 10:1) gave
6b (2.14 g, 10.06 mmol) in 97% yield as a colorless liquid.
Under argon atmosphere, to a CH2Cl2 (10 mL) solution of 6b
(346 mg, 1.6 mmol) was added DIBAL (1.6 mmol, 1.2 mL as
1.5 M toluene solution) at -78 °C and the resulting mixture
was stirred for 4 h at the same temperature. The reaction
was quenched by 5 mL of water containing 1 g of SiO2 powder.
After further stirred for 15 min at room temperature, silica
gel was filtered off through a sintered glass filter. The
17.1, 5.8), 2.64 (1H, dd, J ) 17.1, 4.0), 4.74-4.83 (1H, m); 13
C
NMR (50 MHz, ppm, CDCl3) 17.68, 18.13, 20.61, 20.75, 30.85,
72.96, 116.48, 170.25; IR (neat, cm-1) 2970, 2250, 1745, 1375,
1235,1030. Anal. Calcd for C8H13NO2: C, 61.91; H, 8.44; N,
9.03. Found: C, 61.83; H, 8.54; N, 8.95.
1-(Cya n om eth yl)p en tyl a ceta te (1e): Rf 0.50 (hexane/
ethyl acetate 3:1); bp 122 °C/3 Torr; 1H NMR (200 MHz, δ,
CDCl3, J ) Hz) 0.88 (3H, t, J ) 6.6), 1.26-1.34 (4H, m), 1.61-
1.73 (2H, m), 2.07 (3H, s), 2.56 (1H, dd, J ) 16.9, 5.0), 2.70
(1H, dd, J ) 16.9, 5.0) 4.95 (1H, tt, J ) 5.4, 5.3); 13C NMR (50
MHz, ppm, CDCl3) 13.73, 20.81, 22.15, 22.77, 27.05, 32.75,
68.60, 116.28, 170.22; IR (neat, cm-1) 2950, 2240, 1735, 1460,
1420, 1370, 1235, 1025. Anal. Calcd for C9H15NO2: C, 63.88;
H, 8.93; N, 8.28. Found: C, 63.75; H, 8.94; N, 8.28.
1-(Cya n om eth yl)n on yl a ceta te (1f): Rf 0.50 (hexane/
ethyl acetate 4:1); bp 158 °C/2.5 Torr (Kugelrohr); 1H NMR
(200 MHz, δ, CDCl3, J ) Hz) 0.86 (3H, t, J ) 6.5), 1.25 (12H,
s), 1.66-1.76 (2H, m), 2.08 (3H, s), 2.57 (1H, dd, J ) 17.0,
5.2), 2.70 (1H, dd, J ) 17.0, 5.2), 4.96 (1H, tt, J ) 5.4, 5.3); 13
C
NMR (50 MHz, ppm, CDCl3) 14.00, 20.85, 22.54, 22.80, 29.12,
29.06, 29.24, 31.70, 33.07, 68.65, 116.28, 170.24; IR (neat, cm-1
)
2920, 2240, 1740, 1460, 1415, 1370, 1230, 1025. Anal. Calcd
for C13H23NO2: C, 69.29; H, 10.29; N, 6.22. Found: C, 69.19;
H, 10.28; N, 6.23.
2-Cya n o-1-cycloh exyleth yl a ceta te (1h ): Rf 0.48 (hex-
ane/ethyl acetate 4:1); bp 166 °C/3.2 Torr (Kugelrohr); 1H NMR
(200 MHz, δ, CDCl3, J ) Hz) 0.85-1.41 (5H, m), 1.63-1.80
(6H, m), 2.10 (3H, s), 2.60 (1H, dd, J ) 17.1, 5.7), 2.70 (1H,
dd, J ) 17.1, 5.0), 4.75-4.84 (1H, m); 13C NMR (50 MHz, ppm,
CDCl3) 20.58, 20.77, 25.46, 25.59, 25.93, 28.15, 40.17, 72.30,
116.52, 170.30; IR (neat, cm-1) 2930, 2250, 1745, 1450, 1370,
1230, 1030. Anal. Calcd for C11H18NO2: C, 67.32; H, 9.24;
N, 7.14. Found: C, 67.53; H, 9.17; N, 7.21.
2-Cya n o-2-p h en yleth yl a ceta te (1i):4a Rf 0.59 (hexane/
ethyl acetate 2:1); mp 115-117 °C; 1H NMR (200 MHz, δ,
CDCl3, J ) Hz) 2.15 (3H, s), 2.89 (2H, d, J ) 5.8), 5.97 (1H, t,
J ) 6.1), 7.39 (5H, s); 13C NMR (50 MHz, ppm, CDCl3) 20.86,

9172 J . Org. Chem., Vol. 62, No. 26, 1997
Itoh et al.
resulting solution was extracted with CH2Cl2, dried over
anhydrous Na2SO4, and evaporated to give aldehyde (R)-7 (315
mg), which was immediately used for further Wittig reaction.
To a solution of propyltriphenylphosphonium bromide (578 mg,
1. 5 mmol) in ether (5 mL) was added n-BuLi (1.5 mmol as
1.6 M hexane solution) at 0 °C to form an orange solution. To
this mixture was added an ether (5 mL) solution of (R)-7 (315
mg) at 0 °C, and the whole was stirred for 4 h at room
temperature. The reaction was quenched by the addition of
aqueous NH4Cl solution and extracted with ether. The organic
layer was dried over MgSO4 and evaporated to give the crude
oil. Silica gel flash column chromatography (hexanes/ether 20:
1) gave silyl ether (R)-8 (280 mg, 1.23 mmol) in 77% yield from
6b. Silyl ether (R)-8 (114 mg, 0. 56 mmol) was hydrogenated
using PtO2 (12 mg) as catalyst under H2 (1 atm) in ethanol
(3.0 mL) at room temperature for 2 days. Silica gel flash
column chromatography (hexanes/ethyl acetate 50:1-20:1)
gave (R)-5 (64.2 mg, 0.49 mmol) in 88% yield.
[R]23 -9.7); 1H NMR (200 MHz, δ, CDCl3, J ) Hz) 0.88-0.97
D
(6H, m), 1.16-1.50 (10H, m), 1.52 (1H, s, OH), 3.51-3.54 (1H,
m); 13C NMR (50 MHz, ppm, CDCl3) 9.87, 14.04, 22.64, 25.33,
30.11, 31.91, 36.90, 73.34; IR (neat, cm-1) 3350, 2930, 2860,
1460, 1380, 1250.
(S)-5 ([R]23 +8.8 (c 0.490, CHCl3)) was prepared by the
D
procedure described above. The spectroscopic data were the
same as (R)-5.
NMR Bin d in g Exp er im en ts. 13C NMR binding studies
(Table 2 and Figure 4) were carried out with a Varian VXR-
200 spectrometer (SC NMR Laboratory of Okayama Univer-
sity). The substrate was dissolved in CDCl3 at a concentration
of 0.05 mol/L in the presence of thiacrown ether 4.
Ack n ow led gm en t. We are grateful to the SC NMR
Laboratory of Okayama University for NMR measure-
ments and to the MALDI-TOF MS laboratory of the
Graduate School of Okayama University for elemental
analysis. We also thank Amano Pharmaceutical Co.,
Ltd. for providing lipases.
(R )-(E /Z)-6-[(t er t -Bu t yld im e t h ylsilyl)oxy]-3-oct e n e
(8): Rf 0.85 (hexane/ethyl acetate 10:1); bp 80 °C/15 Torr
(Kugelrohr); [R]23 +16.1 (c 0.84, CHCl3); 1H NMR (200 MHz,
D
δ, CDCl3, J ) Hz) 0.05 (6H, s), 0.84-1.00 (6H, m), 0.87 (9H,
s), 2.03 (2H, dd, J ) 14.0, 6.0) 2.17 (2H, dd, J ) 12.7, 6.2),
3.60 (1H, dt, J ) 11.6, 5.9), 5.38 (1H, m) 5.41 (1H, m); 13C
NMR (50 MHz, ppm, CDCl3) 9.73, 14.24, 18.17, 20.72, 25.69,
25.93, 29.49, 34.70, 40.21, 73.58, 73.74, 125.39, 125.77, 133.03,
134.12; IR (neat, cm-1) 2960, 1460, 1250, 1040, 840, 770. Anal.
Calcd for C14H30OSi: C, 69.35; H, 12.47. Found: C, 69.00; H,
12.50.
Su p p or tin g In for m a tion Ava ila ble: IR, 1H NMR, and
13C NMR spectra for 1b-j, 2b-j, (R)-8, and (R)-5 (60 pages).
This material is contained in libraries on microfiche, im-
mediately follows this article in the microfilm version of the
journal, and can be ordered from the ACS; see any current
masthead page for ordering information.
(R)-3-Octa n ol (5):9a Rf 0.19 (hexane/ethyl acetate 10:1);bp
88 °C/30 Torr (Kugelrohr); [R]23 -9.5 (c 0.960, CHCl3) (lit.9a
J O971288M
D