An efficient route for the allylation of arylaldehydes to give enantiopure homoallylic alcohols

Article abstract of DOI:10.1016/j.tetasy.2013.08.016

An efficient asymmetric synthesis of homoallylic alcohols is described by the allylation of carbonyl compounds using organocatalysts as chiral directors in the presence of tin metal. The effect of chiral environment is also studied on the allylation reactions. This method allows us to obtain two different enantiomers of homoallylic alcohol in the presence of the corresponding chiral compound. The protocol is applied to various aldehydes to obtain high yields and excellent enantioselectivities for the corresponding homoallylic alcohols.

Full text of DOI:10.1016/j.tetasy.2013.08.016

Tetrahedron: Asymmetry 24 (2013) 1324–1330
Contents lists available at ScienceDirect
Tetrahedron: Asymmetry
journal homepage: www.elsevier.com/locate/tetasy
An efficient route for the allylation of arylaldehydes to give
enantiopure homoallylic alcohols
⇑
Prashant B. Thorat, Santosh V. Goswami, Sudhakar R. Bhusare
Department of Chemistry, Dnyanopasak College, Parbhani 431401, MS, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 23 July 2013
Accepted 28 August 2013
Available online 30 September 2013
An efficient asymmetric synthesis of homoallylic alcohols is described by the allylation of carbonyl com-
pounds using organocatalysts as chiral directors in the presence of tin metal. The effect of chiral environ-
ment is also studied on the allylation reactions. This method allows us to obtain two different
enantiomers of homoallylic alcohol in the presence of the corresponding chiral compound. The protocol
is applied to various aldehydes to obtain high yields and excellent enantioselectivities for the correspond-
ing homoallylic alcohols.
Ó 2013 Elsevier Ltd. All rights reserved.
1. Introduction
applied in combination with metals for the development of more
valuable chemical transformations.
Optically active homoallylic alcohols are indispensable scaffolds
in the synthesis of natural products1 and various biologically active
compounds.2 Some enantiopure homoallylic alcohols are used to
craft liquid crystal displays.3 Homoallylic alcohols can be obtained
by asymmetric transformations of aldehydes using allyl-transfer
reagents. The known synthetic routes to obtain homoallylic alco-
hols make use of allyl reagents such as allylsilanes,4,5 allylstann-
anes,6 allylindium,7 allylboranes8 and allyl bromide,9 which have
been studied to a great extent.
Allylation using allylic organometallic reagents is relatively dif-
ficult because they are unstable towards air and moisture. As a re-
sult, the reactions have to be carried out under an inert atmosphere
and at low temperatures. In recent times many reports have been
documented on the Barbier protocols, which involve the genera-
tion of an organometallic reagent in situ using organic halides
and metals4 such as In,10 Sb,11 Pb,12 Mn,13 Fe,14 Mg,15 Zn16 and
Sn.17 After a literature review we noticed that allylation reactions
using tin metal have advantages such as simple reaction set up
since tin metal does not require strictly dry conditions or an inert
atmosphere, and most importantly these compounds are inexpen-
sive and easily available.18 In the reactions using tin metal, reactive
organostannanes are generated in situ from Sn(0/II/IV).19
In our previous communications21 we have reported pyrrolidine
based neutral chiral organocatalysts in which enantioselectivities
were driven primarily by hydrogen bonding, steric and electronic
interactions. High levels of both enantioselectivity and diastere-
oselectivity were achieved for aldol reactions with catalyst 1 and
excellent enantioselectivities were obtained for both the Baylis–
Hillman and the Henry reactions with catalyst 2 (Fig. 1).
O
O
O
S
N
N
HN
Me
HN
F
Ts
O
O
1
2
Figure 1. Chiral L-pyrrolidine based organic catalyst.
In metal-complex mediated reactions, the presence of a chiral
molecule has a strong influence on the stereo chemical outcome
of the product, while a small change in the structure of the chiral
organic molecule can alter the geometry of the product.22
O
O
O
O
O
S
N
N
N
Me
F
In recent years, the search for more efficient asymmetric stere-
oselective reactions has led to the combination of organocatalysis
with transition metal catalysis.20 In metal mediated enantioselec-
tive catalytic reactions, the metal activates the reagents to form
well governed transition states, which transform chiral informa-
tion. Organocatalysis has experienced great advances; it can be
Ts
O
O
3
4
O
O
O
O
S
N
NO2
O
Me
Ts
O
O
5
6
⇑
Corresponding author. Tel.: +91 9850775511.
E-mail address: bhusare71@yahoo.com (S.R. Bhusare).
Figure 2. Chiral L-pyrrolidine based organic promoters.
0957-4166/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tetasy.2013.08.016

P. B. Thorat et al. / Tetrahedron: Asymmetry 24 (2013) 1324–1330
1325
In connection with this and in continuation of our work on
asymmetric reactions,21,23 we herein report the application of
organocatalysts to enantioselective allylations of aldehydes. We
have synthesized some new chiral compounds with different
substituents at the stereogenic centre of the pyrrolidine ring and
its effect on the stereo nature of obtained products was investigated
(see Fig. 2).
and 6 gave unproductive yields with lower enantioselectivity for
the respective products 9a. It is worth mentioning here that the
N-acylated chiral molecules were more efficient than the
N-tosylated molecules. Among all six compounds, catalysts 1 and
3 were superior to catalysts 2 and 4–6. As a result, we opted to
use catalysts 1 and 3 for further experimentations.
Various experiments were performed in order to extract and
optimize the best reaction conditions for catalysts 1 and 3. For in-
stance, the reaction was performed using various concentrations of
catalysts 1 and 3. Both catalysts 1 and 3 at a catalytic loading of
15 mol % were able to give higher yields for their respective prod-
ucts 9a with good ee values. An additional increase in the quanti-
ties of compounds 1 and 3 did not lead to an improvement in the
results to a significant extent.
In subsequent studies, the reaction was also screened with var-
ious solvents in order to examine solvent effect. The reactions were
performed using chiral catalysts 1 and 3 at the optimum concen-
tration. In the reaction, we observed that although polar solvents
had a positive effect on the reaction with respect to yield of the
corresponding product, we also observed that protic solvents
diminished the enantioselectivity. Among all of the protic solvents,
water showed the deleterious effect on enantioselectivity of the
respective product followed by ethanol and methanol. Conversely,
using DMSO as the solvent led to good to moderate ee in both cat-
alysts but relatively lower yields for product 9a. In the non-polar
solvent chloroform, the catalysts could not catalyse the reaction
efficiently.
2. Result and discussion
In order to study the electronic effects and the effect of the
chiral substituents of the catalysts, we synthesized some new
organic molecules 3–6 and employed these catalysts in allylation
reactions. The chiral catalysts were synthesized by known literature
methods.
We started our investigation with the model reaction of
4-nitrobenzaldehyde (1 mmol) and allyl bromide (4 mmol) in the
presence of tin metal (5 mol %) in N,N-dimethylformamide solvent
to obtain 1-(4-nitrophenyl) but-3-en-1-ol 9a. The catalytic efficien-
cies of chiral catalyst 1–6 were tested using 10 mol % of catalyst at
room temperature. As shown in Table 1, compounds 1–6 catalysed
the reactions with different behaviours, offering the respective
products 9a with a range of enantioselectivities. Catalysts 2 and
4 displayed lower activity which was due to the bulky tosyl group
that caused an overcrowded transient state. Among the N-acylated
compounds, catalysts 1 and 3 exhibited better catalytic efficiency.
The use of catalysts 1 and 3 provided the corresponding product 9a
in good yields and enantioselectivities. The good catalytic efficien-
cies of catalysts 1 and 3 can be attributed to the presence of the
sulfonamide or sulfanyl group at the stereogenic carbon atom of
pyrrolidine. In comparison to catalysts 1 and 3, both catalysts 5
Next, we attempted different combinations of N,N-dimethyl-
formamide with water to determine the optimum reaction media.
The reaction was investigated using 15 mol % of catalyst 1 and the
obtained optimum reaction conditions were extended to catalyst 3.
Table 1
Effect of chiral catalyst, catalytic loading and solvent on the synthesis of 9aa
OH
Sn metal
catalyst
Br
+
CHO
O2N
solvent
O2N
9a
7a
8
Entry
Catalyst
Catalytic loading
Solvent
Yieldb (%)
eec (%)
Confign.d
1
2
3
4
5
6
7
8
1
2
3
4
5
6
1
3
1
3
1
3
1
3
1
3
1
3
1
3
1
1
1
3
10
10
10
10
10
10
15
15
20
20
15
15
15
15
15
15
15
15
15
15
15
15
15
15
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
Water
Water
Ethanol
Ethanol
Methanol
Methanol
DMSO
69
36
68
29
54
48
79
72
77
73
66
71
54
55
59
61
61
53
40
43
89
95
73
87
68
40
64
39
49
41
75
71
68
68
44
52
48
46
49
50
67
59
42
39
84
94
66
91
(S)
(S)
(S)
(S)
(S)
(S)
(S)
(S)
(S)
(S)
(R)
(R)
(R)
(R)
(R)
(R)
(S)
(S)
(S)
(S)
(S)
(S)
(S)
(R)
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
DMSO
Chloroform
Chloroform
DMF:Water (50:50)
DMF:Water (60:40)
DMF:Water (70:30)
DMF:Water (60:40)
a
b
c
Conditions: 4-nitrobenzaldehyde (1 mmol), allyl bromide(1.2 mmol), solvent (20 mL) and tin metal (5 mol %) Reaction was stirred at room temperature for 24 h.
Isolated yield.
The enantiomeric excess was determined by chiral HPLC.
d
The absolute configurations were assigned by comparison of the sign of the specific rotations with the ones reported in the literature.24

1326
P. B. Thorat et al. / Tetrahedron: Asymmetry 24 (2013) 1324–1330
Table 2
Asymmetric allylation of aromatic aldehydes using optimized conditionsa
OH
CHO
OH
Sn, Compound 1
Sn, Compound 3
DMF-H2O, RT
Br
DMF-H2O, RT
(S)
(R)
Br
R
R
R
Entry
1
R
Product
Yieldb (%)
eec (%)
Confign.d
4-NO2
9a
95
87
92
85
88
84
86
80
91
89
93
90
89
86
85
81
87
79
91
84
72
66
94
91
95
90
92
88
90
89
96
90
94
90
93
91
88
87
90
91
92
89
78
71
(S)
(R)
(S)
(R)
(S)
(R)
(S)
(R)
(S)
(R)
(S)
(R)
(S)
(R)
(S)
(R)
(S)
(R)
(S)
(R)
(S)
(R)
2
2-NO2
4-Cl
2-Cl
4-F
9b
9c
9d
9e
9f
3
4
5
6
4-Br
H
7
9g
9h
9i
8
4-OCH3
2-OCH3
4-CH3
9
10
11
9j
1-Naphthyl
9k
CHO
83
80
88
83
(S)
(R)
12
9l
N
S
O
77
69
84
87
(S)
(R)
CHO
CHO
13
14
9m
9n
79
74
87
89
(S)
(R)
a
b
c
Conditions: arylaldehyde (1 mmol), allyl bromide (4.0 mmol), solvent (20 mL) and tin metal (5 mol %) Reaction was stirred at room temperature for 24 h.
Isolated yields.
Determined by chiral-phase HPLC analysis of the product.
d
The absolute configurations were assigned by comparison of the sign of the specific rotations with the ones reported in the literature.
When both solvents were used in 50:50 compositions, a notewor-
thy enhancement in the yield and enantioselectivity of the product
9a was obtained. The best results were obtained using a composi-
tion of 60:40. Up to 95% yield was obtained for product 9a with a
maximum enantioselectivity of 94%. The optimum conditions also
worked well for chiral catalyst 3, with product 9a being obtained in
excellent yield and enantioselectivity.
From the results summarized in Table 1, it was noted that protic
and aprotic solvents favored the (R)- and (S)-configuration respec-
tively for the corresponding product. Catalyst 1 at optimum reac-
tion conditions yielded the (S)-stereoisomer with excellent yield
and ee for 1-(4-nitrophenyl) but-3-en-1-ol; compound 3 under
identical reaction conditions gave the (R)-stereoisomer for the
same product. The above results demonstrate that the chiral nature
of the organic catalyst and the solvent have a great influence on the
stereoselectivity of obtained products.
3. Conclusion
In conclusion, we have demonstrated a general method for tin
mediated enantioselective allylations to obtain both the (R)- and
(S)-enantiomers of homoallylic alcohols using different chiral pro-
moters. We have synthesized different chiral catalysts and utilized
them in tin metal mediated allylation reaction. It was found that
under the influence of chiral promoters, the reaction gave a range
of diverse results. The reaction was found to proceed most effi-
ciently with catalysts 1 and 3 at room temperature to yield the
(R)- and (S)-enantiomer, respectively. Both enantiomers of homo-
allylic alcohol products were obtained with high enantiomeric
excesses and in excellent yields. To the best of our knowledge, this
is one of the rare methods that gives both enantiomers of homoal-
lylic alcohols by alteration of chiral promoters under identical
reaction conditions.
The scope of the method was explored to other aromatic alde-
hydes using both chiral promoters 1 and 3 in the presence of tin
metal in DMF–water as the solvent system (Table 2). The reaction
proceeded smoothly at room temperature for almost all aldehydes
to give high to moderate yields and excellent enantioselectivity.
4. Experimental
4.1. General details
The catalysts showed
aldehydes.
a broad applicability towards various
All solvents were used as commercial anhydrous grade with-
out further purification. Aluminium sheets 20 ꢀ 20 cm, Silica gel

P. B. Thorat et al. / Tetrahedron: Asymmetry 24 (2013) 1324–1330
1327
60 F254, Merck grade was used for thin layer chromatography to
4.5. General procedure for the synthesis of organocatalysts 4
and 6
determine the progress of reaction. The column chromatography
was carried out over silica gel (80–120 mesh). Optical rotations
were measured on a Polax-2L digital polarimeter. Melting points
were determined in an open capillary tube and are uncorrected.
1H and 13C NMR spectra were recorded on a Bruker 300 MHz
spectrometer in CDCl3. Mass spectra were taken on Polaris-Q
Thermoscientific GC–MS. The enantiomeric purity was deter-
mined on a PerkinElmer Series 200 HPLC Systems with chiral
HPLC.
The organocatalysts were prepared by the above procedure
using (S)-1-tosylpyrrolidine-2-carboxylic acid and p-cresol/4-fluo-
rophenol as the starting compounds.
4.5.1. (S)-4-Fluorophenyl 1-tosylpyrrolidine-2-carboxylate 4
White solid, (338 mg, 74%), mp 152–154 °C, ½a D27
¼ ꢂ102:9 (c
ꢁ
0.5, ethyl acetate); 1H NMR (300 MHz, CDCl3): d 7.69–7.77 (m,
2H), 7.39–7.47 (m, 2H), 7.22–7.34 (m, 4H), 4.17 (t, J = 8.6 Hz, 1H),
3.73 (t, J = 7.9 Hz, 2H), 3.38 (m, 2H), 2.51 (s, 3H), 2.14–2.19 (m,
2H); 13C NMR (75 MHz, CDCl3): d 169.6, 158.4, 144.9, 141.6,
130.6, 128.3, 125.1, 118.2, 56.6, 56.0, 28.6, 21.3, 19.8; GC–MS:
m/z 363 (M+); Anal. Calcd for: C18H18FNO4S: C, 59.49; H, 4.99; F,
5.23; N, 3.85; Found: C, 59.52; H, 5.03; F, 5.28; N, 3.88. HPLC:
76% ee. [Determined by chiral HPLC with Whelk-O1
(25 cm ꢀ 4.6 mm), Hexane/Ethanol (75/25) + 15 mM Ammonium
Acetate, Flow rate 1.5 mL/min, ´ = 254 nm; tR (minor) = 15.2 min,
tR (major) = 19.0 min.]
4.2. Typical procedure for preparation of acylation of
L-proline
The acylation of
L
-proline is reported in the literature.21
4.3. Typical procedure for preparation of (S)-1-tosylpyrrolidine-
2-carboxylic acid
The synthesis of the titled compound is reported in the
literature.21
4.5.2. (S)-p-Tolyl 1-tosylpyrrolidine-2-carboxylate 6
4.4. General procedure for the synthesis of organocatalysts 3
and 5
White solid, (338 mg, 74%), mp 152–154 °C, ½a D27
¼ ꢂ119:9 (c
ꢁ
0.5, ethyl acetate); 1H NMR (300 MHz, CDCl3): d 7.74–7.83 (m,
2H), 7.46–7.54 (m, 2H), 7.14–7.28 (m, 4H), 4.23 (t, J = 9.1 Hz, 1H),
3.67 (t, J = 8.8 Hz, 2H), 3.32 (m, 2H), 2.46 (s, 6H), 2.19–2.23 (m,
2H); 13C NMR (75 MHz, CDCl3): d 170.2, 147.5, 141.3, 139.8,
136.2, 130.1, 129.8, 128.8, 120.9, 56.1, 55.7, 28.1, 22.4, 18.8; GC–
MS: m/z 359 (M+); Anal. Calcd for: C19H21NO4S: C, 63.49; H, 5.89;
N, 3.90; Found: C, 63.49; H, 5.87; N, 3.93. HPLC: 76% ee. [Deter-
mined by chiral HPLC with Whelk-O1 (25 cm ꢀ 4.6 mm), Hexane/
Ethanol (75/25) + 15 mM Ammonium Acetate, Flow rate 1.5 mL/
min, ´ = 254 nm; tR (minor) = 17.9 min, tR (major) = 22.5 min.]
A mixture of 4-methylbenzenesulfonic acid/4-nitrobenzene-
sulfonic acid (1 mmol) and (S)-1-acetylpyrrolidine-2-carboxylic
acid (1 mmol) acid was added to tetrahydrofuran. The resulting
mixture was kept in an ice bath and cooled to 0 °C, followed by
the addition of the solution of diethyl azodicarboxylate (1 mmol)
and triphenylphosphine (1 mmol) dissolved in THF. The reaction
mixture was then stirred for 24 h. After the formation of the prod-
uct as indicated by chromatography, the reaction mixture was
added to ice cold water, stirred and extracted with chloroform.
The extracted organic layer was dried over Na2SO4 and chloroform
was removed under vacuum to obtain a crude product. The crude
product was further purified with column chromatography using
ethyl acetate: pet ether (4:6) to obtain the pure product.
4.6. General procedure for the synthesis of 9a–n
To a mixture of the aromatic aldehyde (1 mmol) and organocat-
alyst 1 or 3 (0.15 mmol) in N,N-dimethylformamide (14 mL) were
added allyl bromide (1.2 mmol) and tin metal (5 mol %) in water
(6 mL). The reaction was stirred at room temperature for 24 h
(Table 2). The reaction progress was monitored by gas chromatog-
raphy. After completion of the reaction as indicated by GC, the
reaction was quenched with ice cold water (15 mL) and extracted
with chloroform (2 ꢀ 10 mL). The solvent was evaporated under
vacuum to obtain the crude product followed by column chroma-
tography purification using silica gel (100–200 mesh) to afford the
pure homoallylic alcohol.
4.4.1. (S)-1-Acetylpyrrolidine-2-carboxylic 4-methylbenzene-
sulfonic anhydride 3
White solid, (301 mg, 76%), mp 134–136 °C, ½a D27
¼ ꢂ94:6 (c 0.5,
ꢁ
ethyl acetate); 1H NMR (300 MHz, CDCl3): d 7.47–7.58 (m, 1H),
4.21 (t, J = 8.2 Hz, 1H), 3.69 (t, J = 8.7 Hz, 2H), 3.31(m, 2H) 2.48 (s,
3H), 2.24–2.30 (m, 2H), 2.14 (s, 3H); 13C NMR (75 MHz, CDCl3): d
176.6, 171.2, 145.3, 140.6, 129.8, 127.7, 59.8, 48.5, 31.2, 26.7,
20.9, 20.2; GC–MS: m/z 311 (M+); Anal. Calcd for: C14H17NO5S: C,
54.01; H, 5.50; N, 4.50; Found: C, 54.04; H, 5.52; N, 4.53. HPLC:
76% ee. [Determined by chiral HPLC with Whelk-O1
(25 cm ꢀ 4.6 mm), Hexane/Ethanol (75/25) + 15 mM Ammonium
Acetate, Flow rate 1.5 mL/min, ´ = 254 nm; tR (minor) = 12.4 min,
tR (major) = 14.7 min.]
4.6.1. (S)-1-(4-Nitrophenyl)but-3-en-1-ol 9a
The product was characterized by comparing the spectroscopic
data with those reported in the literature.24 Pale yellow oil,
½
a 2D7
ꢁ
¼ ꢂ13:1 (c 3.5, benzene), Lit: +12.9 (c 3.5, benzene) for the
(R)-enantiomer;24 1H NMR (300 MHz, CDCl3): d 8.27–8.35 (m,
2H), 7.45–7.53 (m, 2H), 5.69–5.76 (m, 1H), 5.19–5.24 (m, 2H),
4.90 (t, J = 7.8 Hz, 1H), 2.45–2.56 (m, 2H), 2.08 (br s, 1H, OH); 13C
NMR (75 MHz, CDCl3): d 147.2, 144.28, 134.5, 128.6, 122.7, 117.1,
73.7, 45.3; GC–MS: m/z 193 (M+); Anal. Calcd for: C10H11NO3: C,
62.17; H, 5.74; N, 7.25; Found: C, 62.20; H, 5.71; N, 7.22; HPLC:
94% ee. [Determined by chiral HPLC with Whelk-O1
(25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate 1.0 mL/min,
k = 220 nm; tR (minor) = 10.3 min, tR (major) = 16.7 min.]
4.4.2. (S)-1-Acetylpyrrolidine-2-carboxylic 4-nitrobenzenesulfo-
nic anhydride 5
Light yellowish solid, (309 mg, 71%), mp 117–119 °C,
½
a 2D7
ꢁ
¼ ꢂ76:4 (c 0.5, ethyl acetate); 1H NMR (300 MHz, CDCl3): d
8.34–8.42 (m, 2H), 8.11–8.20 (m, 2H), 4.18 (t, J = 7.9 Hz, 1H), 3.72
(t, J = 9.1 Hz, 2H), 3.26 (m, 2H) 2.52 (s, 3H), 2.22–2.31 (m, 2H);
13C NMR (75 MHz, CDCl3): d 178.2, 173.4, 156.7, 149.9, 128.4,
126.3, 57.6, 47.9, 29.5, 24.3, 21.2; GC–MS: m/z 342 (M+); Anal.
Calcd for: C13H14N2O7S: C, 45.61; H, 4.12; N, 8.18; Found: C,
45.64; H, 4.08; N, 8.21. HPLC: 76% ee. [Determined by chiral HPLC
with Whelk-O1 (25 cm ꢀ 4.6 mm), Hexane/Ethanol (75/25) + 15
mM Ammonium Acetate, Flow rate 1.5 mL/min, ´ = 254 nm;
tR (minor) = 11.6 min, tR (major) = 16.8 min.]
4.6.2. (R) 1-(4-Nitrophenyl) but-3-en-1-ol
The characterization data of the product are the same as above.
Pale yellow oil, ½a D27
¼ þ13:4 (c 3.5, benzene), Lit: +12.9 (c 3.5,
ꢁ
benzene);24 HPLC: 91% ee. [Determined by chiral HPLC with

1328
P. B. Thorat et al. / Tetrahedron: Asymmetry 24 (2013) 1324–1330
Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate 1.0 mL/
min, k = 220 nm; tR (major) = 10.3 min, tR (minor) = 16.7 min.]
4.6.9. (S)-1-(4-Fluorophenyl)but-3-en-1-ol 9e
The product was characterized by comparing the spectroscopic
data with those reported in the literature.24 colourless oil,
4.6.3. (S)-1-(2-Nitrophenyl)but-3-en-1-ol 9b
½
a 2D7
ꢁ
¼ ꢂ21:5 (c 2.0, benzene), Lit: ½a D27
¼ þ21:5 (c 2.0, benzene)
ꢁ
The product was characterized by comparing the spectroscopic
for the (R)-enantiomer;24 1H NMR (300 MHz, CDCl3): d 7.58–7.66
(m, 2H), 7.43–7.49 (m, 2H), 5.75–5.84 (m, 1H), 5.21–5.26 (m,
2H), 4.87 (t, J = 8.2 Hz, 1H), 2.52–2.56 (m, 2H), 2.03 (br s, 1H,
OH); 13C NMR (75 MHz, CDCl3): d 162.5, 141.1, 133.6, 127.9,
117.6, 116.7,76.7, 43.9; GC–MS: m/z 166 (M+); Anal. Calcd for:
data with those reported in the literature.24 Pale yellow oil,
½
a 2D7
ꢁ
¼ ꢂ36:9 (c 2.9, benzene), Lit: ½a D27
ꢁ
¼ ꢂ37:1 (c 2.9, benzene);24
1H NMR (300 MHz, CDCl3): d 8.12–8.17 (m, 1H), 7.71–7.78 (m, 1H),
7.58–7.69 (m, 2H), 5.67–5.74 (m, 1H), 5.22–5.29 (m, 2H), 4.87 (t,
J = 8.1 Hz, 1H), 2.39–2.45 (m, 2H), 2.04 (br s, 1H, OH); 13C NMR
(75 MHz, CDCl3): d 138.4, 136.1, 134.3, 130.1, 129.8, 127.9, 127.3,
116.9, 72.6, 44.1; GC–MS: m/z 193 (M+); Anal. Calcd for:
C10H11FO: C, 72.27; H, 6.67; Found: C, 72.24; H, 6.70; HPLC: 96%
ee. [Determined by chiral HPLC with Whelk-O1 (25 cm ꢀ 4.6 mm),
2% IPA/hexane, Flow rate 1.0 mL/min, k = 220 nm; tR (minor) = 9.5
min, tR (major) = 13.3 min.]
C10H11NO3: C, 62.17; H, 5.74; N, 7.25; Found: C, 62.15; H, 5.77;
N, 7.28; HPLC: 95% ee. [Determined by chiral HPLC with Whelk-
O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate 1.0 mL/min,
k = 220 nm; tR (minor) = 12.4 min, tR (major) = 18.1 min.]
4.6.10. (R)-1-(4-Fluorophenyl)but-3-en-1-ol
The characterization data of the product are the same as above.
Colourless oil, ½a D27
ꢁ
¼ þ21:2 (c 2.0, benzene), Lit: ½a D27
¼ þ21:5 (c
ꢁ
4.6.4. (R)-1-(2-Nitrophenyl)but-3-en-1-ol
2.0, benzene)24; HPLC: 90% ee. [Determined by chiral HPLC with
Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate 1.0 mL/
min, k = 220 nm; tR (major) = 9.5 min, tR (minor) = 13.3 min.]
The characterization data of the product are the same as above.
Pale yellow oil, ½a D27
ꢁ
¼ þ37:4 (c 2.9, benzene), Lit: ½a D27
¼ ꢂ37:1 (c
ꢁ
2.9, benzene) for the (S)-enantiomer;24 HPLC: 90% ee. [Determined
by chiral HPLC with Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane,
Flow rate 1.0 mL/min, k = 220 nm; tR (major) = 12.4 min, tR
(minor) = 18.1 min.]
4.6.11. (S)-1-(4-Bromophenyl)but-3-en-1-ol 9f
The product was characterized by comparing the spectroscopic
data with those reported in the literature.24 Colourless oil,
½
a 2D7
ꢁ
¼ ꢂ12:5 (c 3.5, benzene), Lit: ½a D27
¼ þ12:6 (c 3.5, benzene)
ꢁ
4.6.5. (S)-1-(4-Chlorophenyl)but-3-en-1-ol 9c
for the (R)-enantiomer;24 1H NMR (300 MHz, CDCl3): d 8.11–8.23
(m, 2H), 7.36–7.47 (m, 2H), 5.81–86 (m, 1H), 5.38–5.44 (m, 2H),
4.73 (t, J = 8.0 Hz, 1H), 2.48–2.55 (m, 2H), 2.06 (br s, 1H, OH); 13C
NMR (75 MHz, CDCl3): d 143.6, 134.4, 132.3, 128.4, 123.5, 115.7,
74.5, 45.2; GC–MS: m/z 225 (M+); Anal. Calcd for: C10H11BrO: C,
52.89; H, 4.88; Found: C, 52.87; H, 4.91; HPLC: 94% ee. [Deter-
mined by chiral HPLC with Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/
hexane, Flow rate 1.0 mL/min, k = 220 nm; tR (minor) = 10.8 min,
tR (major) = 14.9 min.]
The product was characterized by comparing the spectroscopic
data with those reported in the literature.24 Colourless oil,
½
a 2D7
ꢁ
¼ ꢂ15:6 (c 2.4, benzene), Lit: ½a D27
¼ þ15:5 (c 2.4, benzene)
ꢁ
for the (R)-enantiomer;24 1H NMR (300 MHz, CDCl3): d 7.54–7.63
(m, 2H), 7.39–7.47 (m, 2H), 5.78–5.82 (m, 1H), 5.16–5.21 (m,
2H), 4.85 (t, J = 7.9 Hz, 1H), 2.42–2.49 (m, 2H), 2.07 (br s, 1H,
OH); 13C NMR (75 MHz, CDCl3): d 140.3, 134.1, 132.8, 131.9,
128.5, 115.8, 73.8, 42.6; GC–MS: m/z 182 (M+); Anal. Calcd for: C10-
H11ClO: C, 65.76; H, 6.07; Found: C, 65.73; H, 6.11; HPLC: 92% ee.
[Determined by chiral HPLC with Whelk-O1 (25 cm ꢀ 4.6 mm),
2% IPA/hexane, Flow rate 1.0 mL/min, k = 220 nm; tR (min-
or) = 15.2 min, tR (major) = 19.0 min.]
4.6.12. (R)-1-(4-Bromophenyl)but-3-en-1-ol
The characterization data of the product are the same as above.
Colourless oil, ½a D27
ꢁ
¼ þ12:9 (c 3.5, benzene), Lit: ½a D27
¼ þ12:6 (c
ꢁ
3.5, benzene);24 HPLC: 90% ee. [Determined by chiral HPLC with
Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate 1.0 mL/
min, k = 220 nm; tR (major) = 10.8 min, tR (minor) = 14.9 min.]
4.6.6. (R)-1-(4-Chlorophenyl)but-3-en-1-ol
The characterization data of the product are the same as above.
Colourless oil, ½a D27
ꢁ
¼ þ15:4 (c 2.4, benzene), Lit: ½a D27
¼ þ15:5 (c
ꢁ
2.4, benzene);24 HPLC: 88% ee. [Determined by chiral HPLC with
Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate 1.0 mL/
min, k = 220 nm; tR (minor) = 15.2 min, tR (major) = 19.0 min.]
4.6.13. (S)-1-Phenylbut-3-en-1-ol 9g
The product was characterized by comparing the spectroscopic
data with those reported in the literature.24 Colourless oil,
½
a 2D7
ꢁ
¼ ꢂ22:0 (c 2.0, benzene), Lit: ½a D27
¼ þ22:3 (c 2.0, benzene)
ꢁ
4.6.7. (S)-1-(2-Chlorophenyl)but-3-en-1-ol 9d
for the (R)-enantiomer;24 1H NMR (300 MHz, CDCl3): d 7.54–7.67
(m, 5H), 5.88–5.94 (m, 1H), 5.31–5.39 (m, 2H), 4.79 (t, J = 8.3 Hz,
1H), 2.61–2.66 (m, 2H), 2.05 (br s, 1H, OH); 13C NMR (75 MHz,
CDCl3): d 145.1, 134.8, 130.6, 128.5, 127.2, 116.3, 73.8, 43.8;
GC–MS: m/z 148 (M+); Anal. Calcd for: C10H12O: C, 81.04; H,
8.16; Found: C, 81.07; H, 8.19; HPLC: 93% ee. [Determined by chiral
HPLC with Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate
1.0 mL/min, k = 220 nm; tR (minor) = 15.6 min, tR (major) =
21.9 min.]
The product was characterized by comparing the spectroscopic
data with those reported in the literature.24 Colourless oil,
½
a 2D7
ꢁ
¼ ꢂ21:3 (c 1.8, CHCl3), ½a D27
¼ þ21:2 (c 1.8, CHCl3) for the
ꢁ
(R)-enantiomer;24 1H NMR (300 MHz, CDCl3): d 7.76–7.81 (m,
1H), 7.42–7.49 (m, 3H), 5.81–5.85 (m, 1H), 5.18–5.24 (m, 2H),
4.87 (t, J = 7.8 Hz, 1H), 2.45–2.52 (m, 2H), 2.03 (br s, 1H, OH); 13C
NMR (75 MHz, CDCl3): d 138.5, 135.3, 133.7, 131.9, 130.4, 126.8,
117.02,72.4, 41.8; GC–MS: m/z 182 (M+); Anal. Calcd for: C10H11-
ClO: C, 65.76; H, 6.07; Found: C, 65.73; H, 6.11; HPLC: 90% ee.
[Determined by chiral HPLC with Whelk-O1 (25 cm ꢀ 4.6 mm),
2% IPA/hexane, Flow rate 1.0 mL/min, k = 220 nm; tR (min-
or) = 14.6 min, tR (major) = 20.1 min.]
4.6.14. (R)-1-Phenylbut-3-en-1-ol
The characterization data of the product are the same as above.
Colourless oil, ½a D27
ꢁ
¼ þ22:1 (c 2.0, benzene), Lit: ½a D27
¼ þ22:3 (c
ꢁ
2.0, benzene);24 HPLC: 91% ee. [Determined by chiral HPLC with
Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate 1.0 mL/
min, k = 220 nm; tR (major) = 15.6 min, tR (minor) = 21.9 min.]
4.6.8. (R)-1-(2-Chlorophenyl)but-3-en-1-ol
The characterization data of the product are the same as above.
Colourless oil, ½a D27
ꢁ
¼ þ20:9 (c 1.8, CHCl3), Lit: ½a D27
¼ þ21:2 (c 1.8,
ꢁ
CHCl3);24 HPLC: 89% ee. [Determined by chiral HPLC with Whelk-
O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate 1.0 mL/min,
k = 220 nm; tR (major) = 14.6 min, tR (minor) = 20.1 min.]
4.6.15. (S)-1-(2-Methoxyphenyl)but-3-en-1-ol 9h
The product was characterized by comparing the spectroscopic
data with those reported in the literature.2a Colourless oil,

P. B. Thorat et al. / Tetrahedron: Asymmetry 24 (2013) 1324–1330
1329
½
a 2D7
ꢁ
¼ ꢂ44:6 (c 2.0, benzene);analogy 1H NMR (300 MHz, CDCl3): d
(m, 1H), 5.23–5.30 (m, 2H), 4.72 (t, J = 7.9 Hz, 1H), 2.37–2.42 (m,
2H), 2.10 (br s, 1H, OH); 13C NMR (75 MHz, CDCl3): d 142.4,
138.6, 135.7, 134.6, 130.3, 129.9, 127.7, 126.8, 126.0, 125.7,
125.3, 115.8, 75.2, 43.4; GC–MS: m/z 198 (M+); Anal. Calcd for:
7.38–7.49 (m, 3H), 7.04–7.13 (m, 3H), 5.78–5.83 (m, 1H), 5.40–
5.46 (m, 2H), 4.74 (t, J = 7.9 Hz, 1H), 3.79 (s, 3H), 2.46–2.53 (m,
2H), 2.07 (br s, 1H, OH); 13C NMR (75 MHz, CDCl3): d 154.4,
134.4, 129.7, 128.3, 127.9, 121.7, 116.5, 114.6, 69.7, 57.3, 42.4;
GC–MS: m/z 148 (M+); Anal. Calcd for: C11H14O2: C, 74.13; H,
7.92; Found: C, 74.17; H, 7.95; HPLC: 84% ee. [Determined by chiral
HPLC with Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane,
Flow rate 1.0 mL/min, k = 220 nm; tR (minor) = 13.1 min, tR
(major) = 22.7 min.]
C14H14O: C, 84.81; H, 7.12; Found: C, 84.83; H, 7.09; HPLC: 78%
ee. [Determined by chiral HPLC with Whelk-O1 (25 cm ꢀ 4.6 mm),
2% IPA/hexane, Flow rate 1.0 mL/min, k = 220 nm; tR (minor) =
18.6 min, tR (major) = 23.0 min.]
4.6.22. (R)-1-(Naphthalen-1-yl)but-3-en-1-ol
The characterization data of the product are the same as above.
4.6.16. (R)-1-(2-Methoxyphenyl)but-3-en-1-ol
Colourless oil, ½a D27
ꢁ
= + 98.6 (c 1.0, benzene);analogy HPLC: 71% ee.
[Determined by chiral HPLC with Whelk-O1 (25 cm ꢀ 4.6 mm),
2% IPA/hexane, Flow rate 1.0 mL/min, k = 220 nm; tR (major) =
18.6 min, tR (minor) = 23.0 min.]
The characterization data of the product are the same as above.
Colourless oil, ½a D27
ꢁ
¼ þ44:1 (c 2.0, benzene);analogy HPLC: 87% ee.
[Determined by chiral HPLC with Whelk-O1 (25 cm ꢀ 4.6 mm),
2% IPA/hexane, Flow rate 1.0 mL/min, k = 220 nm; tR (major) =
13.1 min, tR (minor) = 22.7 min.]
4.6.23. (S)-1-(3-Pyridyl)but-3-en-1-ol 9l
The product was characterized by comparing the spectroscopic
4.6.17. (S)-1-(4-Methoxyphenyl)but-3-en-1-ol 9i
The product was characterized by comparing the spectroscopic
data with those reported in the literature. Colourless oil,
data with those reported in the literature.25 brown oil, ½a D27
ꢁ =ꢂ40.0
(c 0.5, CH2Cl2), Lit:
½
a 2D7
ꢁ
=ꢂ39.9 (c 0.5, CH2Cl2);27a 1H NMR
(300 MHz, CDCl3): d 8.61 (s, 1H), 8.47–8.53 (d, J = 5.6 Hz, 1H),
7.91–7.96 (m, 1H), 7.43–7.56 (m, 1H), 5.79–5.83 (m, 1H), 5.18–
5.23 (m, 2H), 4.69 (t, J = 6.4 Hz, 1H), 2.57 (br s, 1H, OH), 2.33–
2.39 (m, 2H); 13C NMR (75 MHz, CDCl3): d 147.4, 146.5, 140.2,
135.1, 134.3, 124.7, 117.7, 72.4, 43.4; GC–MS: m/z 149 (M+); Anal.
Calcd for: C9H11NO: C, 72.46; H, 7.43; N, 9.39; Found: C, 72.49; H,
7.41; N, 9.42; HPLC: 88% ee. [Determined by chiral HPLC with
Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate 1.0 mL/
min, k = 220 nm; tR (minor) = 24.1 min, tR (major) = 27.5 min.]
½
a 2D7
ꢁ
=ꢂ15.6 (c 1.6, benzene), Lit: ½a D27
ꢁ
= + 15.4 (c 1.6, benzene) for
the (R)-enantiomer;24 1H NMR (300 MHz, CDCl3): d 7.47–7.56 (m,
2H), 6.95–7.07 (m, 2H), 5.81–5.85 (m, 1H), 5.33–5.39 (m, 2H),
4.83 (t, J = 7.6 Hz, 1H), 3.77 (s, 3H), 2.35–2.41 (m, 2H), 2.03 (br s,
1H, OH); 13C NMR (75 MHz, CDCl3): d 156.5, 137.4, 134.8, 128.5,
117.1, 115.8, 72.3, 56.2, 40.6; GC–MS: m/z 148 (M+); Anal. Calcd
for: C11H14O2: C, 74.13; H, 7.92; Found: C, 74.17; H, 7.95; HPLC:
90% ee. [Determined by chiral HPLC with Whelk-O1
(25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate 1.0 mL/min,
k = 220 nm; tR (minor) = 10.1 min, tR (major) = 15.4 min.]
4.6.24. (R)-1-(3-Pyridyl)but-3-en-1-ol
The characterization data of the product are the same as above.
4.6.18. (R)-1-(4-Methoxyphenyl)but-3-en-1-ol
Brown oil, ½a 2D7
ꢁ
= + 39.8 (c 1.15, CH2Cl2), Lit: ½a D27
ꢁ =ꢂ39.9 (c 1.15,
The characterization data of the product are the same as above.
CH2Cl2) for the (S)-enantiomer;25 HPLC: 83% ee. [Determined by
chiral HPLC with Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane,
Flow rate 1.0 mL/min, k = 220 nm; tR (major) = 24.1 min, tR
(minor) = 27.5 min.]
Colourless oil, ½a D27
ꢁ
= + 15.1 (c 1.6, benzene), Lit: ½a D27
ꢁ
= + 15.4 (c 1.6,
benzene);24 HPLC: 91% ee. [Determined by chiral HPLC with
Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate 1.0 mL/
min, k = 220 nm; tR (major) = 10.1 min, tR (minor) = 15.4 min.]
4.6.25. (S)-1-(Thiophen-2-yl)but-3-en-1-ol 9m
4.6.19. (S)-1-p-Tolylbut-3-en-1-ol 9j
The product was characterized by comparing the spectroscopic
The product was characterized by comparing the spectroscopic
data with those reported in the literature.27a Colourless oil,
data with those reported in the literature.24 Colourless oil,
½
a 2D7
ꢁ
=ꢂ8.3 (c 1.20, CH2Cl2), Lit: ½a D27
ꢁ
=ꢂ8.2 (c 1.20, CH2Cl2);25 1H
½
a 2D7
ꢁ
=ꢂ15.3 (c 2.0, benzene), Lit: ½a D27
ꢁ
= + 15.5 (c 2.0, benzene) for
NMR (300 MHz, CDCl3): d 7.33–7.37 (m, 1H), 7.10–7.18 (m, 2H),
5.90–5.94 (m, 1H), 5.20–5.26 (m, 2H), 4.89 (t, J = 5.3 Hz, 1H),
2.41–2.46 (m, 2H), 2.17 (br s, 1H, OH); 13C NMR (75 MHz, CDCl3):
d 146.8, 134.6, 126.4, 125.3, 123.8, 117.3, 71.3, 42.8; GC–MS: m/z
154 (M+); Anal. Calcd for: C8H10OS: C, 62.30; H, 6.54; Found: C,
62.33; H, 6.57; HPLC: 84% ee. [Determined by chiral HPLC with
Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate 1.0 mL/
min, k = 220 nm; tR (minor) = 19.6 min, tR (major) = 23.9 min.]
the (R)-enantiomer;24 1H NMR (300 MHz, CDCl3): d 7.37–7.44 (m,
2H), 7.21–7.32 (m, 2H), 5.77–5.82 (m, 1H), 5.41–5.47 (m, 2H),
4.76 (t, J = 7.9 Hz, 1H), 2.44–2.50 (m, 2H), 2.38 (s, 3H), 2.04 (br s,
1H, OH); 13C NMR (75 MHz, CDCl3): d 141.2, 136.4, 134.8, 128.7,
123.6, 116.3, 71.8, 41.4, 21.7; GC–MS: m/z 162 (M+); Anal. Calcd
for: C11H14O: C, 81.44; H, 8.70; Found: C, 81.48; H, 8.73; HPLC:
92% ee. [Determined by chiral HPLC with Whelk-O1
(25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate 1.0 mL/min,
k = 220 nm; tR (minor) = 8.9 min, tR (major) = 13.5 min.]
4.6.26. (R)-1-(Thiophen-2-yl)but-3-en-1-ol
The characterization data of the product are the same as above.
4.6.20. (R)-1-p-Tolylbut-3-en-1-ol
Colourless oil, ½a D27
ꢁ
= + 8.0 (c 1.20, CH2Cl2), Lit: ½a D27
ꢁ =ꢂ8.2 (c 1.20,
The characterization data of the product are the same as above.
CH2Cl2) for the (S)-enantiomer;25 HPLC: 87% ee. [Determined by
chiral HPLC with Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane,
Flow rate 1.0 mL/min, k = 220 nm; tR (major) = 19.6 min, tR
(minor) = 23.9 min.]
Colourless oil, ½a D27
ꢁ
= + 15.1 (c 2.0, benzene), Lit: ½a D27
ꢁ
= + 15.5 (c 2.0,
benzene);24 HPLC: 89% ee. [Determined by chiral HPLC with
Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate 1.0 mL/
min, k = 220 nm; tR (major) = 8.9 min, tR (minor) = 13.5 min.]
4.6.27. (S)-1-(Furan-2-yl)but-3-en-1-ol 9n
4.6.21. (S)-1-(Naphthalen-1-yl)but-3-en-1-ol 9k
The product was characterized by comparing the spectroscopic
The product was characterized by comparing the spectroscopic
data with those reported in the literature.27a Colourless oil,
data with those reported in the literature.2a Colourless oil,
½
a 2D7
ꢁ
=ꢂ32.7 (c 0.5, CH2Cl2), Lit: ½a D27
ꢁ
=ꢂ32.6 (c 0.5, CH2Cl2);25 1H
½
a 2D7
ꢁ
=ꢂ99.0 (c 1.0, benzene);analogy 1H NMR (300 MHz, CDCl3): d
NMR (300 MHz, CDCl3): d 7.47–7.58 (m, 1H), 6.51–6.62 (m, 2H),
5.86–5.91 (m, 1H), 5.25–5.32 (m, 2H), 4.81 (t, J = 5.7 Hz, 1H),
2.27–2.32 (m, 2H), 2.09 (br s, 1H, OH); 13C NMR (75 MHz, CDCl3):
7.91–8.09 (m, 1H), 7.97–8.02 (m, 1H), 7.78–7.82 (m, 1H), 7.60–
7.72 (m, 2H), 7.47–7.55 (m, 1H), 7.12–7.19 (m, 1H), 5.86–5.90

1330
P. B. Thorat et al. / Tetrahedron: Asymmetry 24 (2013) 1324–1330
6. (a) Haddad, T. D.; Hirayama, L. C.; Taynton, P.; Singaram, B. Tetrahedron Lett.
¨uer, A.; Oltra, J.
E.; Cuerva, J. M. Chem. Commun. 2004, 2628.
7. Barker, T. J.; Jarvo, E. R. Org. Lett. 2009, 11, 1047.
8. (a) Takeshi, T.; Hideki, W.; Akira, T. Tetrahedron Lett. 2011, 52, 4575; (b) Miller,
J. J.; Sigman, M. S. J. Am. Chem. Soc. 2007, 129, 2752; (c) Hargaden, G. C.; Guiry,
P. J. Adv. Synth. Catal. 2007, 349, 2407.
d 157.6, 142.4, 133.9, 116.9, 112.3, 109.6, 70.1, 43.8; GC–MS: m/z
138 (M+); Anal. Calcd for: C8H10O2: C, 69.54; H, 7.30; Found: C,
69.54; H, 7.30; HPLC: 87% ee. [Determined by chiral HPLC with
Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane, Flow rate 1.0 mL/
min, k = 220 nm; tR (minor) = 20.1 min, tR (major) = 24.7 min.]
2008, 49, 508; (b) Rosales, A.; Oller-Lopez, J. L.; Justicia, J.; Gansa
9. Nowrouzi, F.; Thadani, A. N.; Batey, R. A. Org. Lett. 2009, 11, 2631.
10. (a) Loh, T. P.; Zhou, J. R.; Yin, Z. Org. Lett. 1999, 1, 1855; (b) Hilt, G.; Ismolko, K.;
Waloch, C. Tetrahedron Lett. 2002, 43, 1437; (c) Tan, K. T.; Chng, S. S.; Cheng, H.
S.; Loh, T. P. J. Am. Chem. Soc. 2003, 125, 2958.
11. (a) Wang, W.; Shi, L.; Huang, Y. Tetrahedron 1990, 46, 3315; (b) Li, L. H.; Chan, T.
H. Tetrahedron Lett. 2000, 41, 5009.
12. Zhou, J. Y.; Jia, Y.; Sun, G. F.; Wu, S. H. Synth. Commun. 1997, 27, 1899.
13. (a) Li, C. J.; Meng, Y.; Yi, X. H.; Ma, J.; Chan, T. H. J. Org. Chem. 1998, 63, 7498; (b)
Li, C. J.; Meng, Y.; Yi, X. H.; Ma, J.; Chan, T. H. J. Org. Chem. 1997, 62, 8632.
14. Chan, T. C.; Lau, C. P.; Chan, T. H. Tetrahedron Lett. 2004, 45, 4189.
15. (a) Wada, M.; Fukuma, T.; Morioka, M.; Takahashi, T.; Miyoshi, N. Tetrahedron
Lett. 1997, 38, 8045; (b) Zhang, W. C.; Li, C. J. J. Org. Chem. 1999, 64, 3230.
16. (a) Wang, J. X.; Jia, X. F.; Meng, T. J.; Xin, L. Synthesis 2005, 17, 2838; (b) Ishino,
Y.; Mihara, M.; Kageyama, M. Tetrahedron Lett. 2002, 43, 6601; (c) Yi, X.;
Haberman, J. X.; Li, C. J. Synth. Commun. 1998, 28, 2999; (d) Marton, D.;
Stivanello, D.; Tagliavini, G. J. Org. Chem. 1996, 61, 2731; (e) Chung, W.;
Higashiya, S.; Oba, Y.; Welch, J. T. Tetrahedron 2003, 59, 10031.
17. (a) Mukaiyama, T.; Harada, T. Chem. Lett. 1981, 1527; (b) Tan, X. H.; Hou, Y. Q.;
Huang, C.; Liu, L.; Guo, Q. X. Tetrahedron 2004, 60, 6129.
4.6.28. (R)-1-(Furan-2-yl)but-3-en-1-ol
The characterization data of the product are the same as above.
Colourless oil, ½a D27
ꢁ
¼ þ32:3 (c 0.5, CH2Cl2), Lit: ½a D27
ꢁ
¼ ꢂ32:3 (c 0.5,
CH2Cl2) for the (S)-enantiomer;25 HPLC: 86% ee. [Determined by
chiral HPLC with Whelk-O1 (25 cm ꢀ 4.6 mm), 2% IPA/hexane,
Flow rate 1.0 mL/min, k = 220 nm; tR (major) = 20.1 min, tR
(minor) = 24.7 min.]
Acknowledgments
We acknowledge, Dr. P. L. More, Dr. W. N. Jadhav, Dnyanopasak
College, Parbhani for providing necessary facilities and IICT
Hyderabad for providing spectral data.
18. Chan, T. H.; Yang, Y.; Li, C. J. J. Org. Chem. 1999, 64, 4452.
19. (a) Li, C. J. Chem. Rev. 2005, 105, 3095; (b) Denmark, S. E.; Fu, J. Chem. Rev. 2003,
103, 2763; (c) Marshall, J. A. Chem. Rev. 2000, 100, 3163.
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