Porcine Liver Esterase Catalyzed Kinetic Resolution of Baylis-Hillman (B-H) Adducts

Article abstract of DOI:10.1081/SCC-120025180

Esterase from porcine liver smoothly resolves varieties of racemic 2-methylene-3-substituted-3-hydroxypropanoates (B-H adducts) to obtain the corresponding unreacted esters in very good to excellent ee (94 to >99%, seven examples) and hydrolyzed acids in good ee (58-75%). Substitution in B-H adducts, chosen for resolution, are funtionalized phenyl, thiophen-3-yl, cinnamyl, and alkyl groups.

Full text of DOI:10.1081/SCC-120025180

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Porcine Liver Esterase Catalyzed Kinetic Resolution of
Baylis-Hillman (B-H) Adducts
Debnath Bhuniya a , Sanju Narayanan a , Taranpreet Singh Lamba a & K. V. S. R. Krishna
Reddy b
a Metabolic Disorder (Chemistry) Group , Dr. Reddy's Laboratories Limited , Miyapur,
Hyderabad, India
b Analytical Group , Discovery Research S.B.U. , Dr. Reddy's Laboratories Limited , Miyapur,
Hyderabad, India
Published online: 16 Aug 2006.
To cite this article: Debnath Bhuniya , Sanju Narayanan , Taranpreet Singh Lamba & K. V. S. R. Krishna Reddy (2003) Porcine
Liver Esterase Catalyzed Kinetic Resolution of Baylis-Hillman (B-H) Adducts, Synthetic Communications: An International
Journal for Rapid Communication of Synthetic Organic Chemistry, 33:21, 3717-3726, DOI: 10.1081/SCC-120025180
To link to this article: http://dx.doi.org/10.1081/SCC-120025180
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SYNTHETIC COMMUNICATIONSÕ
Vol. 33, No. 21, pp. 3717–3726, 2003
Porcine Liver Esterase Catalyzed Kinetic
Resolution of Baylis-Hillman (B-H) Adductsy
1
Debnath Bhuniya,1, Sanju Narayanan,
*
Taranpreet Singh Lamba,1 and K. V. S. R. Krishna Reddy2
1Metabolic Disorder (Chemistry) Group, and
2Analytical Group, Discovery Research S.B.U.,
Dr. Reddy’s Laboratories Limited,
Miyapur, Hyderabad, India
ABSTRACT
Esterase from porcine liver smoothly resolves varieties of racemic
2-methylene-3-substituted-3-hydroxypropanoates (B-H adducts) to
obtain the corresponding unreacted esters in very good to excellent
ee (94 to >99%, seven examples) and hydrolyzed acids in good ee
(58–75%). Substitution in B-H adducts, chosen for resolution, are
funtionalized phenyl, thiophen-3-yl, cinnamyl, and alkyl groups.
yDRL Pub. No. 232. Dedicated to Dr. A. Venkateswarlu on the occasion of his
63rd birth anniversary.
*Correspondence: Debnath Bhuniya, Metabolic Disorder (Chemistry)
Group, Discovery Research S.B.U., Dr. Reddy’s Laboratories Limited,
Miyapur, Bollaram Road, Hyderabad 500050, India; Fax: þ91 40 2304 5438;
E-mail: debnathbhuniya@drreddys.com.
3717
DOI: 10.1081/SCC-120025180
Copyright & 2003 by Marcel Dekker, Inc.
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3718
Bhuniya et al.
Key Words: Baylis-Hillman adducts; Kinetic resolution; Porcine
liver esterase.
INTRODUCTION
Synthesis of 2-(methylene)-3-hydroxypropanoate(s), the Baylis-
Hillman (B-H) adducts,[1] in homochiral form is a challenging task.[2]
Initial attempts from various research groups to obtain enantiopure B-H
adducts yielded only few successful reports mainly based on the strategies
of kinetic resolution. Noyori and co-workers while doing asymmetric
hydrogenation of various racemic allylic alcohols, reported kinetic
resolution of (ꢀ)-1 by carrying out (S )-BINAP-Ru diacetate catalyzed
hydrogenation which led to isolation of (S )-1 in >99% ee.[3,4] However
both the Refs. [3] and [4] lack generality of the approach on kinetic
resolution of B-H adducts as substrates. Lipase catalyzed resolution of
racemic B-H adducts was studied independently by different groups[5]
where originally Burgess and Jennings[5a] reported 72 to >95% ee for (S )-
2 (10 examples, R1: lower alkyl and alkoxy). Horseradish peroxide (HRP)
catalyzed kinetic resolution of hydroperoxide derivatives of B-H adducts,
(ꢀ)-3 (two examples), were studied by Adam et al. where >99% ee have
been achieved.[6] Interestingly, the B-H adducts, chosen in the above
citations, except two examples in Ref. [4], are based on aliphatic aldehydes
i.e., 3-alkyl substituted cases. To the best of our knowledge, only Basavaiah
and Dharma Rao reported kinetic resolution of a series of B-H adducts
derived from aromatic aldehydes using pig liver acetone powder (PLAP).[7]
They reported a highest ee of 86% for deacetylated product obtained from
(ꢀ)-4 when Ar is 1-napthyl and EWG is cyano, and for the rest of examples
ee ranges from 46 to 70%.[7] Figure 1 represents the compounds 1–4.
Owing to the difficulty in achieving successful asymmetric synthesis of
B-H products, partly due to the slow progress of the reaction,[8] an effi-
cient, convenient, and general way to resolve racemic B-H products is still
a quest for many research groups. As it reflects from a recent work from
Trost et al., who studied C2-symmetric ligand-Pd(0) complex assisted
R3
OAc
OOH
OH
O
OH
O
EWG
CO2Me
CO2Me
EWG
(Pr)Me
R1
Ar
(Et)Me
R2
(+) - 4
(S) - 1
(S) - 2
(+) - 3
(+) - 5
-
-
-
Figure 1.

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Baylis-Hillman (B-H) Adducts
3719
dynamic kinetic asymmetric transformation (DYKAT) of several racemic
B-H adducts (ꢀ)-5 (Fig. 1: R3 is methoxycarbonyl group) and obtained the
corresponding O-aryl derivatives (S)-5 (R3 is aryl) in 39 to >99% ee. Here
also R2 in 5 is limited to only aliphatic groups.[9]
In this communication, we disclose porcine liver esterase catalyzed
kinetic resolution of B-H adducts 6 obtained from aromatic, hetero-
aromatic, cinnamyl as well as aliphatic aldehydes reacting with ethyl
acrylate.
RESULTS AND DISCUSSION
Examples 6a–d were conveniently synthesized in gram scale (50–60%
yield) using equimolar quantities of ethyl acrylate and the corresponding
aldehydes in MeCN, DMF, or dioxane solvent (2.0 M) using 20 mol% of
DABCO at RT.[10a] For 6e–g, reactions were done by heating (70ꢁC)
overnight at neat condition in sealed tube (40–60% yield).[10b,c] Table 1
outlines these synthesis.
Esterase from porcine liver (Sigma, EC 3.1.1.1, Lot No. 40K7060, 41
units per mg solid) was chosen for hydrolysis of the B-H adducts 6a–g.
We designed the incubation protocol in such way that the hydrolysis cum
resolution proceeds reasonably faster and the procedure becomes
useful for laboratory synthesis of homochiral B-H adducts. Initially the
hydrolysis reaction was standardized using the substrates 6a and 6b in
aqueous phosphate buffer (pH 7.2) along with organic co-solvents
(1–10% with respect to buffer) like acetone, DMSO, DMF, DMA, and
Table 1. Synthesis of Baylis-Hillman adducts 6a–g.
OH
DABCO (0.2 eq)
Solvent (2.0 M) / neat
O
CO2Et
CO2Et
6a-g
R
+
R
H
R
Solvent
Condition
Isolated yield
B-H adducts
p-NO2-phenyl
m-NO2-phenyl
p-F-Phenyl
MeCN
MeCN
DMF
Dioxane
Neat
RT, 24 h
RT, 24 h
RT, 24 h
RT, 24 h
70ꢁC, 16 h
70ꢁC, 16 h
70ꢁC, 16 h
60%
55%
55%
50%
60%
40%
40%
6a
6b
6c
6d
6e
6f
m-Hydroxy-phenyl
Thiophen-3-yl
Cinnamyl
Neat
Neat
Isobutyl
6g

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3720
Bhuniya et al.
1,4-dioxane. Reaction temperature was preferred at 35–36ꢁC. We
observed that all the studied co-solvents gave more or less similar results
both in terms of yield and ee of the products. However, hydrolysis
practically did not proceed in the absence of co-solvent. Hence for
illustration purpose we are presenting the results based on reactions
carried out using DMSO as co-solvent (Table 2).
As it was expected the ee of hydrolyzed acid and recovered ester were
found to be very much dependent on progress of hydrolysis, which also
supports kinetic resolution. Thus when the reactions, in general, were
stopped in the late stage (approx. 70% conversion) the recovered
esters showed excellent ee (i.e., 94 to >99%) for 6. On the other hand
when the hydrolysis was interrupted at the early stage (approx. 25–30%
conversion), the corresponding acids 7 were obtained in the range of
58–75% ee. A compromised ee (in the range of 76–92%) of the recovered
esters could also be obtained with improved isolated yield of 40–46%, as
indicated by the Entries 1a, 2a, 3a (Table 2). Based on the literature evi-
dences[11] (see also Table 2), stereochemistry of all the resolved esters 6
were assigned as (S ), and opposite stereochemistry were assigned for
the acids 7. It is to be noted here that the resolved 6e and 7e, though possess
general trend of absolute stereochemistry, are assigned to have respectively
(R) and (S ) stereochemistry due to change in priority. This indicates that
the enzyme recognizes the D-stereochemistry of ester for hydrolysis.
From the structural diversity of the examples disclosed in Table 2,
it also indicates that this approach could be made general for kinetic
resolution of B-H adducts derived from ethyl acrylate and aromatic,
aliphatic, hereoaromatic, a,b-unsaturated aldehydes.
Enantiomeric ratio (E) is another important parameter for any
kinetic resolution study specially of present interest. For each enzymatic
hydrolysis studied here, the calculated E value[12] has been shown in
Table 2. E is a constant and specific to a substrate and enzyme used
for kinetic resolution. We also substantiate this principle. As for example
E for kinetic resolution of 6a remains same (9.6, 9.5, 9.0) in three different
extent of hydrolysis.
CONCLUSIONS
We have discovered a convenient way of achieving optically pure
Baylis-Hillman (B-H) products based on esterase-catalyzed hydrolysis
cum kinetic resolution. The approach is shown to be quite general as
varieties of B-H adducts, based on ethyl acrylate and aromatic, aliphatic,
a,b-unsaturated, as well as heteroaromatic aldehydes, could be resolved

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Baylis-Hillman (B-H) Adducts
3721
Table 2. Kinetic resolution of B-H adducts 6a–g through esterase-catalyzed
hydrolysis.
OH
O
OH
O
Esterase (Porcine Liver),
phosphate buffer (pH = 7.2),
DMSO (7.5 %), 36 oC
OH
O
R
OEt
R
OH
+
R
OEt
) - 6a
(R
) - 7b
6
(S
(S)-6
(R)-7
Reaction
B-H adduct time (h) Yieldc % eed Yieldc % eed Ef
Entry
1a
R-
6a
16
40
92
55
50e
9.6
O2N
O2N
1b
1c
2a
24
2
30
65
46
>99
42e
65
30
50
35
70
9.5
9.0
6.8
6b
6c
7
91e
40e
2b
2c
3a
16
35
60
45
>99
48e
76
60
30
52
15e
75
5.2
11.4
4.9
0.5
4
38
F
3b
3c
4a
16
30
70
30
>99
20e
99
65
25
65
17e
64
5.4
5.4
4.3
0.5
HO
6d
6e
24
10
4b
5a
2
24
65
32
18e
97
28
65
60
25
4.8
5.7
S
5b
6a
2
28
65
25
16e
99
30
56
66
26
6.2
7.1
6f
6b
7a
7b
2
28
1
55
35
65
20e
94
14e
25
60
28
72
15
58
7.1
3.7
6.1
6g
aSpecific rotation of resolved 6a–e are positive, and the same is negative for 7a–e.
Whereas specific rotation of resolved 6f–g are negative, and the same is positive
for 7f–g. Comparison of specific rotation of 6a, 6f, and 6g with the literature
value[11] justified the (S)-configuration. For others, in general, it is tentative
assignment based on analogy. See text for stereochemistry assignment of 6e.
bAbsolute configuration of 7a–d, and 7f–g was assigned as (R), and for 7e as
(S), after esterifying the acids into their ethyl esters and comparing the specific
c
rotation with 6. Isolated yield of recovered ester 6 and the corresponding acid 7
which were characterized by routine spectra. d% ee were determined by chiral
e
HPLC method, unless mentioned. % ee was calculated based on comparison of
specific rotation with authentic sample for which the % ee was determined by
chiral HPLC. fCalculated following the equation: E ¼ ln[(1 ꢀ c)(1 ꢀ eeS)]/ln
[(1 ꢀ c)(1 þ eeS)]. The extent of conversion c ¼ eeS/(eeS þ eeP), where eeS and eeP
are for resolved esters and hydrolyzed acids respectively.[12]

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3722
Bhuniya et al.
in very high to excellent ee (94 to >99%). Though kinetic resolution of
B-H adducts either via enzyme assisted[5–7] or using chemical discrimi-
nation approach[3,4,9] have been reported in the past, each of them has
their own limitation as described in the introduction part. The present
study shows that using procine liver esterase the structural limitations of
B-H adducts may be overcome.
EXPERIMENTAL
1H and 13C NMR spectra were recorded on Mercury Plus (Varian
400 MHz), and Gemini (Varian 200 MHz) spectrometer in CDCl3 with
TMS as internal standard: chemical shifts are quoted in ppm and J values
are given in Hz. IR spectra were recorded on FT-IR spectrophotometer
from Perkin-Elmer 1600 series. Mass spectra were recorded on Hewlett-
Packard 5989A LC-Mass spectrometer using isobutene as chemical
ionizer gas (source temp. 250ꢁC and quadruple temp. 100ꢁC), or on
triple quadrupole mass spectrometer, PE Sliex model API 3000 (at
þ5000 V). Elemental analysis were done on Perkin-Elmer II series.
In a typical procedure for esterase-catalyzed hydrolysis, 6e (600 mg,
2.83 mmol) was added to a mixture of phosphate buffer (pH 7.2, 240 mL)
and DMSO (18 mL). Finally enzyme (20 mg) was added and the
mixture was stirred at 35–36ꢁC for 24 h, at which time TLC indicated
approximately 70% conversion. The reaction mixture was acidified
to adjust the pH at 2–3. Ethyl acetate extraction gave the crude mass
containing unreacted (R)-6e and the corresponding acid (S)-7e, which
were isolated by column chromatography. Yield: (R)-6e (192 mg, 32%),
and (S)-7e (338 mg, 65%).
Compounds 6a–d, 6f–g were also resolved to obtain the corre-
sponding optically pure (S)-6a–d, and (S)-6f–g respectively following
the typical procedure described for 6e. Characterization of all resolved
B-H adducts are as below.
Characterization of (S)-6a. HPLC: Chiralpak AD-H (250 ꢂ 4.6 mm);
Hexane:EtOH::95:05 (1.0 mL/min); uv-273 nm; tR of (R)-6a: 29.91 min
(0.25% area), tR of (S)-6a: 32.35 min (99.60% area). [a]D þ93.8ꢁ (c 1.0,
MeOH). 1H NMR (CDCl3, 400 MHz) ꢀ: 1.26 (t, J ¼ 7.0 Hz, 3H), 3.38 (bs,
1H, -OH), 4.18 (q, J ¼ 7.0 Hz, 2H); 5.61 (s, 1H), 5.83 (t, J ¼ 1.0 Hz, 1H),
6.37 (d, J ¼ 0.8 Hz, 1H), 7.55 (d, J ¼ 8.8 Hz, 2H), 8.17 (d, J ¼ 8.8 Hz, 2H).
13C NMR (CDCl3, 50 MHz) ꢀ: 13.91, 61.20, 72.32, 123.45 (2C), 126.76,
127.37 (2C), 141.27, 147.24, 148.88, 165.84. MS (ES) m/z: 525.3
[M2 þ Naþ], 520.3 [M2 þ NH4þ], 274.0 [M þ Naþ], 269.0 [M þ NH4þ],

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Baylis-Hillman (B-H) Adducts
3723
252.1 [M þ 1], 233.9 [Mꢃ17(OH)]. IR (neat) cmꢃ1: 3489, 2984, 1711, 1522,
1349. Anal. calcd. for C12H13NO5: C, 57.37; H, 5.22; N, 5.58. Found: C,
57.25; H, 5.28; N, 5.51.
Characterization of (S)-6b. HPLC: Chiralpak AD-H (250 ꢂ 4.6 mm);
Hexane:EtOH::95:05 (1.0 mL/min); uv-273 nm; tR of (S)-6b: 22.50 min
(99.86% area), tR of (R)-6b: 28.40 min (0.14% area). [a]D þ86.1ꢁ (c 2.25,
1
MeOH). H NMR (CDCl3, 400 MHz) ꢀ: 1.26 (t, J ¼ 7.0 Hz, 3H), 3.30 (d,
J ¼ 6.2 Hz, 1H, -OH), 4.18 (q, J ¼ 7.0 Hz, 2H), 5.61 (d, J ¼ 6.2 Hz, 1H),
5.85 (t, J ¼ 1.0 Hz, 1H), 6.38 (t, J ¼ 0.8 Hz, 1H), 7.50 (t, J ¼ 7.8 Hz, 1H),
7.71–7.73 (aromatics, 1H), 8.11–8.13 (aromatics, 1H); 8.23–8.24 (aro-
matics, 1H). 13C NMR (CDCl3, 50 MHz) ꢀ: 13.91, 61.19, 72.29, 121.53,
122.60, 126.74, 129.24, 132.72, 141.26, 143.78, 148.16, 165.84. þMS (ES)
m/z: 525.2 [M2 þ Naþ], 520.3 [M2 þ NH4þ], 274.3 [M þ Na ], 269.1
[M þ NH4þ], 252.3 [M þ 1], 234.1 [Mꢃ17(OH)]. IR (neat) cmꢃ1: 3484,
2985, 1711, 1531, 1351. Anal. calcd. for C12H13NO5: C, 57.37; H, 5.22;
N, 5.58. Found: C, 57.19; H, 5.25; N, 5.61.
Characterization of (S)-6c. HPLC: Chiralpak AD-H (250 ꢂ 4.6 mm);
Hexane:i-PrOH::95:05 (1.0 mL/min); uv-220 nm; tR of (S)-6c: 10.30 min
(99.63% area), tR of (R)-6c: 10.97 min (0.37% area). [a]D þ98.3ꢁ (c 3.25,
MeOH). 1H NMR (CDCl3, 400 MHz) ꢀ: 1.24 (t, J ¼ 7.2 Hz, 3H), 3.20 (bs,
1H, -OH), 4.16 (q, J ¼ 7.2 Hz, 2H), 5.52 (s, 1H), 5.78 (t, J ¼ 1.0 Hz, 1H),
6.31 (s, 1H), 7.00 (t, J ¼ 8.8 Hz, 2H), 7.32 (dd, J ¼ 8.2, 5.3 Hz, 2H).
13C NMR (CDCl3, 50 MHz) ꢀ: 13.95, 60.93, 72.52, 115.00 (d,
J ¼ 21.5 Hz, 2C), 125.68, 128.30 (d, J ¼ 8 Hz, 2C), 137.15 (d, J ¼ 3 Hz,
1C), 142.15, 162.11 (d, J ¼ 244.5 Hz, 1C), 166.19. MS (CI) m/z: 224
[M], 207 [Mꢃ17 (OH)]. IR (neat) cmꢃ1: 3456, 2985, 1713. Anal. calcd.
for C12H13FO3: C, 64.28; H, 5.84. Found: C, 64.25; H, 5.87.
Characterization of (S)-6d. HPLC: Chiralpak AD-H (250 ꢂ 4.6 mm);
Hexane:i-PrOH::95:05 (1.0 mL/min); uv-220 nm; tR of (R)-6d: 49.15 min
(0.48% area), tR of (S)-6d: 52.40 min (99.52% area). [a]D þ74.1ꢁ (c 1.9,
MeOH). 1H NMR (CDCl3, 400 MHz) ꢀ: 1.25 (t, J ¼ 7.1 Hz, 3H); 3.50 (bs,
1H, -OH), 4.16 (q, J ¼ 7.1 Hz, 2H), 5.50 (s, 1H), 5.82 (s, 1H), 6.32 (s, 1H),
6.37 (bs, 1H, phenolic-OH); 6.73 (ddd, J ¼ 8.2, 1.5, 1.0 Hz, 1H); 6.84–6.86
(aromatics, 2H), 7.16 (t, J ¼ 8.0 Hz, 1H). 13C NMR (CDCl3, 50 MHz) ꢀ:
13.77, 61.10, 72.59, 113.69, 114.99, 118.57, 126.06, 129.484, 141.61,
142.50, 155.96, 166.53. MS (CI) m/z: 222 [M], 205 [Mꢃ17(OH)]. IR
(neat) cmꢃ1: 3392, 2985, 1701. Anal. calcd. for C12H14O4: C, 64.85; H,
6.35. Found: C, 64.69; H, 6.37.
Characterization of (R)-6e. HPLC: Chiralpak AD-H (250 ꢂ 4.6 mm);
Hexane:EtOH::95:05 (1.0 mL/min); uv-235 nm; tR of (S)-6e: 15.7 min
(1.29% area), tR of (R)-6e: 16.8 min (97.91% area). [a]D þ120ꢁ (c 1.0,
1
MeOH). H NMR (CDCl3, 400 MHz) ꢀ: 1.24 (t, J ¼ 7.3 Hz, 3H), 3.34

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3724
Bhuniya et al.
(s, 1H, -OH), 4.17 (q, J ¼ 7.3 Hz, 2H), 5.58 (s, 1H), 5.80 (t, J ¼ 1.2 Hz,
1H), 6.28 (s, 1H), 7.00 (dd, J ¼ 4.9, 1.2 Hz, 1H), 7.18 (dd, J ¼ 2.9, 1 Hz,
1H), 7.24 (dd, J ¼ 5.4, 2.9 Hz, 1H). 13C NMR (CDCl3, 50 MHz) ꢀ: 13.78,
60.66, 69.08, 121.61, 125.11, 125.58, 126.07, 141.91, 142.89, 166.05. MS
(ES) m/z: 447.1 [M2 þ Naþ], 235.1 [M þ Naþ], 195.1 [Mꢃ17(OH)]. IR
(neat) cmꢃ1: 3442, 2982, 1712, 1268, 1149, 1039. Anal. calcd. for
C10H12O3S: C, 56.58; H, 5.70. Found: C, 56.61; H, 5.81.
Characterization of (S)-6f. HPLC: Chiralpak AD-H (250 ꢂ 4.6 mm);
Hexane:i-PrOH::94:06 (0.5 mL/min); uv-254 nm; tR of (S)-6f: 27.18 min
(98.12% area), tR of (R)-6f: 28.53 min (0.67% area). [a]D ꢃ14.4ꢁ (c 1.0,
1
CHCl3). H NMR (CDCl3, 400 MHz) ꢀ: 1.31 (t, J ¼ 7.3 Hz, 3H), 2.95 (d,
J ¼ 6.4 Hz, 1H, -OH), 4.24 (q, J ¼ 7.3 Hz, 2H), 5.11 (t, J ¼ 6.4 Hz, 1H),
5.88(s, 1H), 6.27(s, 1H), 6.28(dd, J ¼ 15.6, 5.8 Hz, 1H), 6.64(d,J ¼ 15.6 Hz,
1H), 7.22–7.38 (aromatics, 5H). 13C NMR (CDCl3, 50 MHz) ꢀ: 13.98,
60.85, 71.73, 125.36, 126.45 (2C), 127.64, 128.41 (2C), 129.26, 131.19,
136.39, 141.48, 166.21. MS (ES) m/z: 255.1 [M þ Naþ] , 250.4
[M þ NH4þ], 215.1 [Mꢃ17(OH)]. IR (neat) cmꢃ1: 3434, 2983, 1713.
Anal. calcd. for C14H16O3: C, 72.39; H, 6.94. Found: C, 72.41; H, 7.03.
Characterization of (S )-6g. HPLC: Chiralpak AD-H (250 ꢂ 4.6 mm);
Hexane:i-PrOH::98:02 (1.0 mL/min); uv-220 nm; tR of (R)-6g: 10.32 min
(3.04% area), tR of (S)-6g: 11.13 min (95.56% area). [a]D ꢃ27ꢁ (c 3.0,
CHCl3). 1H NMR (CDCl3, 200 MHz) ꢀ: 0.88 (d, J ¼ 2.4 Hz, 3H), 0.91 (d,
J ¼ 2.5 Hz, 3H), 1.27 (t, J ¼ 7.3 Hz, 3H), 1.30–1.60 (m, 2H), 1.62–1.82 (m,
1H), 2.81 (bs, 1H, -OH), 4.19 (q, J ¼ 7.3 Hz, 2H), 4.43 (dd, J ¼ 8.7, 4.6,
1H), 5.75 (s, 1H), 6.17 (s, 1H). 13C NMR (CDCl3, 50 MHz) ꢀ: 13.99,
21.65, 23.19, 24.65, 45.48, 60.65, 69.52, 124.18, 143.31, 166.53. MS (CI)
m/z: 187 [M þ 1] , 169 [Mꢃ17(OH)]. IR (neat) cmꢃ1: 3422, 2958, 1716.
Anal. calcd. for C10H18O3: C, 64.49; H, 9.74. Found: C, 64.35; H, 9.81.
ACKNOWLEDGMENTS
We acknowledge Drs. Sanjay Trehan and R. Rajagopalan for scien-
tific discussions and their overall support. Shweta Shah (IIT Delhi, India)
who did summer project with us is being acknowledged for carrying out
some initial experiments.
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Baylis-Hillman (B-H) Adducts
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Received in the UK November 19, 2002