Bifunctionalized allenes, Part IX: An efficient method for regioselective synthesis of 4-heteroatom-functionalized allenecarboxylates

Article abstract of DOI:10.1002/hc.21096

An efficient method for regioselective synthesis of 4-heteroatom- functionalized allenecarboxylates by an atom economical [2,3]-sigmatropic rearrangement of the mediated 2-heteroatom-functionalized alk-3-ynecarboxylates is described. Alkyl 4-(dimethoxypho

Full text of DOI:10.1002/hc.21096

Heteroatom Chemistry
Volume 24, Number 4, 2013
Bifunctionalized Allenes, Part IX: An Efficient
Method for Regioselective Synthesis of
4-Heteroatom-Functionalized
Allenecarboxylates
Ivaylo K. Ivanov, Ivaylo D. Parushev, and Valerij Ch. Christov
Department of Organic Chemistry & Technology, Faculty of Natural Sciences, Konstantin
Preslavsky University of Shumen, BG-9712 Shumen, Bulgaria
Received 10 January 2013; revised 12 April 2013
bon atom is the identifying structural characteris-
ABSTRACT: An efficient method for regioselective
tic of allenes, and it is this unique structural and
synthesis of 4-heteroatom-functionalized allenecar-
electronic arrangement that is responsible for the
boxylates by an atom economical [2,3]-sigmatropic
extraordinary reactivity profile displayed by allenic
rearrangement of the mediated 2-heteroatom-
compounds [1].
functionalized alk-3-ynecarboxylates is described.
Functionalized allenes have attracted a growing
Alkyl
4-(dimethoxyphosphoryl),
(diphenylphos-
attention because of their versatility as key build-
ing blocks for organic synthesis. The synthetic po-
tential of functionalized allenes has been extensively
explored in recent years and this has led to the de-
velopment of novel methods for the construction of
a variety of functionalized heterocyclic and carbo-
cyclic systems [2].
phinoyl), (benzenesulfinyl), or (methanesulfonyl)-
alka-2,3-dienoates can be readily prepared via
reactions of alkyl 2-hydroxy-alk-3-ynoates with
dimethylchlorophosphite, chlorodiphenylphosphine,
benzensulfanyl chloride, or methanesulfinyl chloride,
ꢀC
respectively, in the presence of a base. 2013 Wiley
Periodicals, Inc. Heteroatom Chem. 24:322–331,
2013; View this article online at wileyonlineli-
brary.com. DOI 10.1002/hc.21096
A plethora of methods exists for the con-
struction of alka-2,3-dienoates, including the Wittig
[3], Wittig–Horner [4], or the Horner–Wadsworth–
Emons [5] olefination of ketenes, iron-catalyzed ole-
fination of ketenes with diazoacetate [6], and by
other methods [7]. There are methods [8] for the syn-
thesis of phosphorus-containing allenes (phospho-
nates [9], phosphinates [10], and phosphine oxides
[11]) including reactions of α-alkynols with chloride-
containing derivatives of phosphorus acids followed
by [2,3]-sigmatropic rearrangement. The reaction of
propargyl alcohols with halogen-containing sulfur
reagents, such as sulfanyl halides [12] and sulfinyl
chlorides [13], is a convenient method for the prepa-
ration of propargyl compounds (sulfenates or sul-
finates), which usually undergo [2,3]-sigmatropic
rearrangement to allenic products (sulfoxides or sul-
fones) [12–14]. An alternative route, which enables
the preparation of 2-thio- [15a], 2-sulfinyl- [15a,15b],
INTRODUCTION
In the past three decades, the synthesis and use of
allene derivatives have been expanded in prepara-
tive organic chemistry. The presence of two π elec-
tron clouds separated by a single sp hybridized car-
Correspondence to: Valerij Ch. Christov; e-mail: vchristo@
shu-bg.net.
Contract grant sponsor: Research Fund of the Konstantin
Preslavsky University of Shumen.
Contract grant number: RD-05-137/2011, RD-05-247/2012.
Contract grant sponsor: National Research Fund of Bulgaria.
Contract grant number: DRNF-02-13/2009.
ꢀC
2013 Wiley Periodicals, Inc.
322

An Efficient Method for Regioselective Synthesis of 4-Heteroatom-Functionalized Allenecarboxylates 323
O
R1
CO2R2
3a–c
R
R1
Mg
1a–c
EtBr
EtMgBr
R
MgBr
R
CO2R2
ether
reflux, 3.5 h
Ether
ether
HO
4a–f
reflux, 2 h
reflux, 2 h
2a–c
SCHEME 1
TABLE 1 Preparation of the Propargylic Alcohols 4a–
f from the Metallated Acetylenes 2a–c and the Alkyl 2-
oxoalkanoates 3a–c
and 2-sulfonyl-substituted [15a] allenecarboxylates,
starts from methyl 4-hydroxy-2-alkynoate.
As a part of our research program on the chem-
istry of the bifunctionalized allenes, we required
a convenient method to introduce a heteroatom-
functionalized group, such as phosphonate, phos-
phine oxide, sulfoxide, or sulfone group, in the four-
position to the ester group of the allenecarboxylates.
The above-mentioned groups attract increasing at-
tention as useful functionalities in organic synthesis.
Of particular interest are the applications of these
groups as temporary transformers of chemical reac-
tivity of the allenic system in the synthesis of even-
tually heterocyclic compounds.
Entry
Product
R
R1
R2
Yielda (%)
1
2
3
4
5
6
4a
4b
4c
4d
4e
4f
Pr
Pr
Bu
Bu
Ph
Ph
Me
Ph
Me
Ph
Me
Ph
Et
Me
Et
Me
Et
Et
76
77
73
72
73
75
aIsolated yields by chromatographical purification.
phine oxides [20], relies on the well-precedented 2,3-
sigmatropic shift of propargylic phosphites to al-
lenephosphonates [9], propargylic phosphinites to
allenyl phosphine oxides [11], propargylic sulfenates
to allenyl sulfoxides [12, 14], and propargylic sul-
finates to allenyl sulfones [13, 14]. Precedence ex-
ists for such an approach to the synthesis of allenic
compounds. However, to the best of our knowledge,
the use of propargylic alcohols bearing an electron-
withdrawing group such as 4, to give the corre-
sponding allenic esters 6, 8, 10, and 12, has not been
reported. To assess this approach toward the tar-
get 4-heteroatom-functionalized allenecarboxylates
6, 8, 10, and 12, a range of propargylic alcohols
4a–f was prepared by the reaction of the metallated
acetylenes 2a–c with commercially available alkyl 2-
oxoalkanoates (pyruvic acid esters) 3a–c (Scheme 1
and Table 1) [21–23].
In a continuation to our previous reports on
the synthesis [16a,16b,16g,16h] and electrophilic cy-
clization reactions [16,16a–f] of bifunctionalized al-
lenes, we have found an efficient method for regios-
elective synthesis of 4-heteroatom-functionalized
allenecarboxylates by an atom economical [2,3]-
sigmatropic rearrangement of the mediated 2-
heteroatom-functionalized alk-3-ynecarboxylates.
RESULTS AND DISCUSSION
Since its discovery five decades ago [9a,10a,10b],
the reversible interconversion of propargylic phos-
phites, phosphonites, and phosphinites to allenyl
phosphonates, phosphinates, and phosphine oxides
has become one of the most studied and synthet-
ically useful [2,3]-sigmatropic rearrangement. Nu-
merous synthetic applications of the rearrangement
have been reported, including its use in the synthesis
of allenic steroids as substrate-induced inactivation
of aromatase [17a], in the efficient synthesis of (2R)-
2-amino-5-phosphonopentanoic acid as a powerful
and selective N-methyl-D-aspartate antagonist [17b],
in the preparation of the phosphonate analogues of
phosphatidyl derivatives [17c,17d], and, in the syn-
thesis of new acyclic analogues of nucleotides con-
taining a purine or pyrimidine moiety and an allenic
skeleton [17e,17f].
With the required propargyl alcohols 4a–f in
hand, we were then able to investigate the pro-
posed reactions with the corresponding chloro-
containing phosphorus and sulfur reagents, such
as dimethylchlorophosphite, chlorodiphenylphos-
phine, benzenesulfanyl chloride, and methane-
sulfinyl chloride in the presence of
a base
and subsequent [2,3]-sigmatropic rearrangement
of the mediated 2-heteroatom-functionalized alk-
3-ynecarboxylates 5, 7, 9, and 11. In the first in-
stance, the alkyl 4-(dimethoxyphosphoryl)-alka-2,3-
dienoates 6a–c,f can be readily prepared via an
atom economical 2,3-sigmatropic rearrangement of
the mediated alkoxycarbonyl-functionalized propar-
gyl phosphite 5a–c,f, intermediate formed by the
Our strategy for the synthesis of the 4-
heteroatom-functionalized allenecarboxylates, us-
ing our experience on the preparation of the
vinylallenyl sulfoxides [18], sulfones [19], and phos-
Heteroatom Chemistry DOI 10.1002/hc

324 Ivanov, Parushev, and Christov
CO2R2
OH
CO2R2
O
CO2R2
O
CO2R2
R1
R1
R1
R1
1. PCl3, Et3N
Ph2PCl
2. 2MeOH, 2Et3N
OH
Et3N
ether, −70oC
P(OMe)2
5a–c,f
R1
CO2R2
ether, −70oC
:
:
PPh2
7c–f
R
R
R
R
4a–c,f
4c–f
R
[2,3]-
R
R1
CO2R2
[2,3]-
•
•
(MeO)2P
ether, rt, 3 h
ether, rt, 5 h
Ph2P
O
O
6a–c,f
8c–f
SCHEME 2
SCHEME 3
TABLE 2 Synthesis of the Alkyl 4-(dimethoxyphosphoryl)-
alka-2,3-dienoates 6a–c,f by [2,3]-Sigmatropic Rear-
rangement of the Mediated 2-(Dimethoxyphosphinooxy)-
alk-3-ynoates 5a–c,f Prepared via Reactions of the Alkyl
2-hydroxy-alk-3-ynoates 4a–c,f with Dimethylchlorophos-
phite in the Presence of a Base
The strategy for the synthesis of sulfur-
containing allenes (sulfoxides and sulfones) re-
lies on the well-precedented [2,3]-sigmatropic rear-
rangement of propargylic sulfenates and sulfinates
to allenyl sulfoxides and sulfones [12–14]. Pleas-
ingly, the reaction of the propargylic alcohols 4a–
c,f with benzenesulfanyl chloride in the presence
of triethylamine led to the formation of the ex-
pected 4-(benzenesulfinyl)-allenoates 8a–c,f, which
were isolated in 59–67% yield after purification
by column chromatography as a result of [2,3]-
sigmatropic rearrangement of the mediated formed
2-(benzenethiooxy)-alk-3-ynecarboxylates 9a–c,f for
7 h at room temperature, as outlined in Scheme 4
and Table 4.
The starting materials in the synthesis of the
alkyl 4-(methanesulfonyl)-alka-2,3-dienoates 12c–f
are the appropriate α-alkoxycarbonyl-α-alkynols
4c–f, which react with methanesulfinyl chloride
in the presence of triethylamine. Reflux of the
intermediate formed alkoxycarbonyl-propargyl
sulfinates 11c–f (which may or may not be isolated)
in dry toluene for 8 h provokes a [2,3]-sigmatropic
Entry
Product
R
R1
R2
Yielda (%)
1
2
3
4
6a
6b
6c
6f
Pr
Pr
Bu
Ph
Me
Ph
Me
Ph
Et
Me
Et
62
69
63
65
Et
aIsolated yields by chromatographical purification.
reaction of the alkyl 2-hydroxy-alk-3-ynoates 4a–
c,f with dimethylchlorophosphite, prepared in situ
from phosphorus trichloride, 2 equiv of methanol,
and 2 equiv of triethylamine, in the presence of tri-
ethylamine, according to Scheme 2 and Table 2.
Pleasingly, the reaction of the alkyl 2-hydroxy-
alk-3-ynoates 4c–f with chlorodiphenylphosphine in
the presence of triethylamine at –70◦C gave the
expected alkyl 4-(diphenylphosphinoyl)-allenoates
8c–f in moderate yields (Table 3) as
a re-
sult of [2,3]-sigmatropic rearrangement of the 2-
(diphenylphosphinooxy)-propargyl esters 7c–f for
5 h at room temperature, according to the reaction
sequence outlined in Scheme 3.
CO2R2
OH
CO2R2
R1
R1
PhSCl
O
Et3N
TABLE 3 Synthesis of the Alkyl 4-(diphenylphosphinoyl)-
alka-2,3-dienoates 8c–f by [2,3]-Sigmatropic Rearrangement
of the Mediated 2-(Diphenylphosphinooxy)-alk-3-ynoates 7c–
f Prepared via Reactions of the Alkyl 2-hydroxy-alk-3-ynoates
4c–f with Chlorodiphenylphosphine in the Presence of a Base
ether, -70oC
:
SPh
9a–c,f
R1
R
R
4a–c,f
R
[2,3]-
Entry
Product
R
R1
R2
Yielda (%)
•
CO2R2
ether, rt, 7 h
1
2
3
4
8c
8d
8e
8f
Bu
Bu
Ph
Ph
Me
Ph
Me
Ph
Et
Me
Et
60
58
57
62
Ph
S
O
10a–c,f
Et
aIsolated yields by chromatographical purification.
SCHEME 4
Heteroatom Chemistry DOI 10.1002/hc

An Efficient Method for Regioselective Synthesis of 4-Heteroatom-Functionalized Allenecarboxylates 325
TABLE 4 Synthesis of the Alkyl 4-(benzenesulfinyl)-alka-
CONCLUSIONS
2,3-dienoates 10a–c,f by [2,3]-Sigmatropic Rearrangement
of the Mediated 2-(Benzenethiooxy)-alk-3-ynoates 9a–c,f
Prepared via Reactions of the Alkyl 2-hydroxy-alk-3-ynoates
4a–c,f with Benzenesulfanyl Chloride in the Presence of a
Base
In conclusion, a convenient and efficient method
for regioselective synthesis of
a new family
of 1,3-diacceptor-substituted allenes, namely 4-
heteroatom-functionalized allenecarboxylates, de-
rived by [2,3]-sigmatropic rearrangement of the
intermediate formed 2-heteroatom-functionalized
alk-3-ynecarboxylates in the reactions of alkyl
2-hydroxy-alk-3-ynoates with dimethylchlorophos-
phite, chlorodiphenylphosphine, benzensulfanyl
chloride, or methanesulfinyl chloride in the presence
of a base has been explored.
Entry
Product
R
R1
R2
Yielda (%)
1
2
3
4
10a
10b
10c
10f
Pr
Pr
Bu
Ph
Me
Ph
Me
Ph
Et
Me
Et
64
64
67
59
Et
aIsolated yields by chromatographical purification.
Further investigations on this potentially im-
portant synthetic methodology are currently in
progress. At the same time, the synthetic applica-
tion of the prepared 4-heteroatom-functionalized al-
lenecarboxylates for the synthesis of different hete-
rocyclic compounds is now under investigation in
our laboratory as a part of our general synthetic
strategy for investigation of the scope and limita-
tions of the electrophilic cyclization reactions of
bifunctionalized allenes. Results of these investiga-
tions will be reported in due course.
CO2R2
R1
CO2R2
O
R1
MeS(O)Cl
OH
Et3N
ether, −70oC
:
S Me
R
R
O
4c–f
11c–f
R
S
R1
[2,3]-
O
•
toluene
reflux, 8 h
CO2R2
Me
O
12c–f
EXPERIMENTAL
General
SCHEME 5
rearrangement to the expected 3-alkoxycarbonyl-
allenyl sulfones 12c–f, which were purified by
column chromatography on silica gel with 46–52%
yield (see Scheme 5 and Table 5).
After a conventional workup, all allenic products
6, 8, 10, and 12 were isolated by column chromatog-
raphy and identified by 1H, 13C, and 31P NMR and IR
spectra as well as by elemental analysis. Some char-
acteristic chemical shifts and coupling constants in
the 13C and 31P NMR spectra of the prepared 1,3-
bifunctionalized allenes 6, 8, 10, and 12 are summa-
rized in Table 6.
All new synthesized compounds were purified by col-
umn chromatography and characterized on the basis
of NMR, IR, and microanalytical data. NMR spectra
were recorded on DRX Brucker Avance-250 (Bruker
BioSpin, Karlsruhe, Germany) (1H at 250.1 MHz,
13C at 62.9 MHz, 31P at 101.2 MHz) and Brucker
Avance II+600 (Bruker BioSpin) (1H at 600.1 MHz,
13C at 150.9 MHz, 31P at 242.9 MHz) spectrome-
ters for solutions in CDCl3. Chemical shifts are in
parts per million downfield from internal TMS (1H
and 13C) and external 85% H3PO4 (31P). J values are
given in hertz. IR spectra were recorded with an
FT-IR Afinity-1 Shimadzu spectrophotometer (Shi-
madzu, Japan). Elemental analyses were carried out
by the Microanalytical Service Laboratory of Fac-
ulty of Chemistry and Pharmacy, University of Sofia
using Vario EL3 CHNS(O) (Elementar Analysensys-
teme, Hanau, Germany). Column chromatography
was performed on Kieselgel F25460 (70–230 mesh
ASTM, 0.063–0.200 nm; Merck). The melting points
were measured in open capillary tubes and are un-
corrected. The solvents were purified by standard
methods. Reactions were carried out in oven-dried
glassware under an argon atmosphere and exclusion
of moisture. All compounds were checked for purity
on TLC plates Kieselgel F25460 (Merck).
TABLE 5 Synthesis of the Alkyl 4-(Methanesulfonyl)-alka-
2,3-dienoates 12c–f by [2,3]-Sigmatropic Rearrangement
of the Mediated 2-(Methanesulfinyloxy)-alk-3-ynoates 11c–f
Prepared via Reactions of the Alkyl 2-Hydroxy-alk-3-ynoates
4c–f with Methanesulfinyl Chloride in the Presence of a Base
Entry
Product
R
R1
R2
Yielda,b (%)
1
2
3
4
12c
12d
12e
12f
Bu
Bu
Ph
Ph
Me
Ph
Me
Ph
Et
Me
Et
48
47
46
Et
52 (54)c
aIsolated yields by chromatographical purification.
bOverall yields without isolation of the alkynes 11c–f.
cOverall yield with isolation of the alkyne 11f.
Heteroatom Chemistry DOI 10.1002/hc

326 Ivanov, Parushev, and Christov
TABLE 6 Some Characteristic 13C and 31P NMR Spectral Data of the Prepared 1,3-Bifunctionalized Allenes 6, 8, 10, and 12
6, Y=P-OMe, R3=OMe
8, Y=P-Ph, R3=Ph
10, Y=S, R3=Ph
R
Y
R1
4
3
•
2
1
R3
CO2R2
O
12, Y=S=O, R3=Me
Allene
δC-1
δC-2
δC-3
δC-4
3JP-C
2JP-C
1JP-C
δ31
P
6a
166.7
165.8
166.7
164.7
166.8
165.8
165.9
164.6
166.0
161.9
166.4
167.8
165.2
164.7
165.3
163.5
97.6
104.6
97.6
105.9
98.1
105.2
99.0
106.1
102.5
106.3
108.9
109.1
111.4
110.8
111.5
110.7
213.3
214.6
213.2
218.1
212.4
213.3
215.8
217.4
206.8
209.5
213.7
216.0
216.1
210.4
212.3
213.9
95.9
98.7
96.0
15.2
15.6
15.2
15.7
13.0
12.9
12.3
12.8
-
-
-
-
-
-
-
-
4.9
4.9
5.0
4.7
6.5
6.4
6.4
7.1
-
-
-
-
-
181.9
184.8
181.7
185.2
94.5
92.9
95.4
97.9
19.3
17.4
19.1
15.6
31.8
29.9
30.6
29.6
-
-
-
-
-
-
-
-
6b
6c
6f
105.8
102.4
104.4
104.3
107.2
115.8
111.1
115.4
108.4
115.5
117.4
116.5
117.4
8c
8d
8e
8f
10a
10b
10c
10f
12c
12d
12e
12f
-
-
-
-
-
-
-
-
-
-
-
is achieved by column chromatography (silica gel,
Kieselgel Merck 60 F254) with ethyl acetate/hexane.
The pure products had the following properties.
Starting Materials
Benzenesulfanyl chloride was prepared from
diphenyl disulfide and sulfuryl chloride in
dichloromethane and distilled in vacuo (bp 80–
81◦C/20 mm Hg) before used [24]. Methanesulfinyl
chloride was prepared from dimethyl disulfide and
sulfuryl chloride in acetic acid and distilled in
vacuo (bp 36◦C/20 mm Hg) before used [25]. Alkyl
2-oxoalkanoates, pentyne, hexyne, phenylacetylene,
phosphorus trichloride, triethylamine, pyridine,
chlorodiphenylphosphine, diphenyl disulfide, and
dimethyl disulfide were commercially available and
were purified by usual methods.
Ethyl 2-hydroxy-2-methyl-hept-3-ynoate (4a).
The compound was described in a U.S. Patent [21]
without giving experimental, NMR, and IR spectral
details. Orange oil, yield: 76%. Eluent for TLC: ethyl
acetate:hexane = 1:1, Rf 0.82; IR (neat, cm−1): 1732
(C O), 2254 (C C), 3496 (OH). 1H NMR (CDCl3,
≡
250.1 MHz, δ): 1.00 (t, J 7.1 Hz, 3H, Me(CH2)2), 1.32
(t, J 7.2 Hz, 3H, MeCH2O), 1.49 (m, 2H, MeCH2CH2),
1.53 (s, 3H, Me), 2.21 (m, 2H, MeCH2CH2), 4.03 (s,
1H, OH), 4.27 (m, 2H, MeCH2O). 13C NMR (CDCl3,
62.9 MHz, δ): 13.3 (CH3), 13.9 (CH3), 22.6 (CH2),
22.9 (CH2), 25.6 (CH3), 61.4 (CH2), 72.9 (C), 78.4
(C), 81.3 (C), 165.7 (C). C10H16O3 (184.23). Calcd: C
65.19, H 8.75; found: C 65.13, H 8.68.
General Procedure for Synthesis of Alkyl
2-hydroxy-alk-3-ynoate (4)
Ethylmagnesium bromide [prepared from magne-
sium (1.22 g, 50 mmol) and ethyl bromide (5.50 g,
50 mmol) in dry diethyl ether (50 mL)] is added
dropwise under stirring to monosubstituted alkynes
1 [pentyne, hexyne, or phenylacetylene (50 mmol)]
and then the mixture is refluxed for 2 h. The solu-
tion of the prepared monosubstituted alkynyl mag-
nesium bromides 3 is added dropwise under stir-
ring to the alkyl 2-oxoalkanoates 3 (100 mmol). The
mixture is refluxed for 3.5 h and after cooling is hy-
drolyzed with a saturated aqueous solution of am-
monium chloride. The organic layer is separated,
washed with water, and dried over magnesium sul-
fate. Solvent and the excess of 2-oxoalkanoate are
removed by distillation. Purification of the residue
Methyl 2-hydroxy-2-phenyl-hept-3-ynoate (4b).
The compound was described in a U.S. Patent [22]
without giving experimental, NMR, and IR spec-
tral details. Light yellow oil, yield: 77%. Eluent for
TLC: ethyl acetate:hexane = 1:1, Rf 0.79; IR (neat,
cm−1): 1450, 1493 (Ph), 1732 (C O), 2251 (C C),
≡
1
3493 (OH). H NMR (CDCl3, 600.1 MHz, δ): 1.03 (t,
J 7.3 Hz, 3H, Me(CH2)2), 1.61 (m, 2H, MeCH2CH2),
2.30 (m, 2H, MeCH2CH2), 3.77 (s, 3H, MeO), 4.16
(s, 1H, OH), 7.32–7.70 (m, 5H, Ph) 13C NMR (CDCl3,
150.9 MHz, δ): 13.6 (CH3), 20.9 (CH2), 21.9 (CH2),
54.2 (CH3), 72.9 (C), 78.4 (C), 87.7 (C), 126.1–139.9
(Ph), 173.2 (C). C14H16O3 (232.28). Calcd: C 72.39,
H 6.94; found: C 72.31, H 7.01.
Heteroatom Chemistry DOI 10.1002/hc

An Efficient Method for Regioselective Synthesis of 4-Heteroatom-Functionalized Allenecarboxylates 327
Ethyl 2-hydroxy-2-methyl-oct-3-ynoate (4c). The
General Procedure for Synthesis of the Alkyl
4-(dimethoxyphosphoryl)-alka-2,3-dienoates
(6a–c,f)
compound was described in a U.S. Patent [21] with-
out giving experimental, NMR, and IR spectral de-
tails. Yellow oil, yield: 73%. Eluent for TLC: ethyl
acetate:hexane = 1:1, Rf 0.79; IR (neat, cm−1): 1736
To a solution of phosphorus trichloride (2.75 g,
20 mmol) and triethylamine (2.23 g, 22 mmol) in dry
diethyl ether (60 mL) at –70◦C, a solution of alkyl 2-
hydroxy-alk-3-ynoates 4 (20 mmol) in the same sol-
vent (20 mL) was added dropwise with stirring. After
30 min stirring at the same temperature, a solution
of pyridine (3.16 g, 44 mmol) and methanol (1,28 g,
40 mmol) in dry diethyl ether (50 mL) was added.
The reaction mixture was stirred for 1 h at the same
temperature and for 3 h at room temperature. Then
the mixture was washed with water, 2 N HCl, ex-
tracted with ether, washed with saturated NaCl, and
dried over anhydrous sodium sulfate. After evapora-
tion of the solvent, the residue was chromatographed
on a column (silica gel, Kieselgel Merck 60 F254) with
a mixture of ethyl acetate and hexane as an eluent to
give the pure products as yellow oils, which had the
following properties.
(C O), 2253 (C C), 3497 (OH). 1H NMR (CDCl3,
≡
600.1 MHz, δ): 0.90 (t, J 7.2 Hz, 3H, Me(CH2)3),
1.33 (t, J 7.1 Hz, 3H, MeCH2O), 1.40 (m, 2H,
MeCH2(CH2)2), 1.49 (m, 2H, MeCH2CH2CH2), 1.65
(s, 3H, Me), 2.25 (m, 2H, MeCH2CH2CH2), 3.48
(s, 1H, OH), 4.29 (q, J 7.1 Hz, 3H, MeCH2O). 13C
NMR (CDCl3, 150.9 MHz, δ): 13.6 (CH3), 14.1 (CH3),
18.3 (CH2), 21.9 (CH2), 27.4 (CH3), 30.4 (CH2),
62.7 (CH2), 67.9 (C), 79.8 (C), 85.0 (C), 173.5 (C).
C11H18O3 (198.26). Calcd: C 66.64, H 9.15; found: C
66.56, H 9.09.
Methyl 2-hydroxy-2-phenyl-oct-3-ynoate (4d).
The compound was described in a U.S. Patent
[22] without giving experimental, NMR, and IR
spectral details. Light yellow oil, yield: 72%. Eluent
for TLC: ethyl acetate:hexane = 1:1, Rf 0.81; IR
(neat, cm−1): 1450, 1493 (Ph), 1732 (C O), 2255
Ethyl 4-(dimethoxyphosphoryl)-2-methyl-hepta-
2,3-dienoate (6a). Yellow oil, yield: 62%. Eluent for
TLC: ethyl acetate:hexane = 1:1, Rf 0.63; IR (neat,
cm−1): 1267 (P O), 1454, 1491 (Ph), 1713 (C O),
1949 (C C C). 1H NMR (CDCl3, 600.1 MHz, δ): 0.97
(t, J 7.4 Hz, 3H, Me(CH2)2), 1.26 (t, J 7.2 Hz, 3H,
MeCH2O), 1.52–1.58 (m, 2H, MeCH2CH2), 1.94 (d, J
6.6 Hz, 3H, Me), 2.23–2.28 (m, 2H, MeCH2CH2), 3.77
(d, J 11.3 Hz, 3H, MeO), 4.19–4.23 (m, 2H, MeCH2O).
13C NMR (CDCl3, 150.9 MHz, δ): 13.5 (CH3), 14.2
(CH3), 14.4 (J 6.1 Hz, CH3), 21.2 (J 6.6 Hz, CH2),
30.7 (J 4.8 Hz, CH2), 53.2 (J 6.1 Hz, CH3), 61.3
(CH2), 95.9 (J 181.9 Hz, C), 97.6 (J 15.2 Hz, C), 166.7
(J 7.7 Hz, C), 213.3 (J 4.9 Hz, C). 31P NMR (CDCl3,
242.9 MHz, δ): 19.3. C12H21O5P (276.27). Calcd: C
52.17, H 7.66; found: C 52.25, H 7.59.
1
≡
(C C), 3493 (OH). H NMR (CDCl3, 250.1 MHz, δ):
0.93 (t, J 7.3 Hz, 3H, Me(CH2)3), 1.37–1.64 (m, 4H,
Me(CH2)2CH2), 2.32 (m, 2H, Me(CH2)2CH2), 3.76
(s, 3H, MeO), 4.12 (s, 1H, OH), 7.31–7.69 (m, 5H,
Ph). 13C NMR (CDCl3, 62.9 MHz, δ): 13.7 (CH3),
18.6 (CH2), 22.1 (CH2), 30.5 (CH2), 54.1 (CH3), 72.9
(C), 78.3 (C), 87.8 (C), 126.3–139.7 (Ph), 172.8 (C).
C15H18O3 (246.30). Calcd: C 73.15, H 7.37; found: C
73.19, H 7.31.
Ethyl 2-hydroxy-2-methyl-4-phenyl-but-3-ynoate
(4e). The compound was described in a U.S. Patent
[21] without giving experimental, NMR, and IR spec-
tral details. Yellow oil, yield: 73%. Eluent for TLC:
ethyl acetate:hexane = 1:1, Rf 0.78; IR (neat, cm−1):
≡
1445, 1489 (Ph), 1732 (C O), 2253 (C C), 3480
(OH). H NMR (CDCl3, 600.1 MHz, δ): 1.36 (t, J 7.1
1
Methyl 4-(dimethoxyphosphoryl)-2-phenyl-hepta-
2,3-dienoate (6b). Yellow oil, yield: 69%. Eluent
for TLC: ethyl acetate:hexane = 1:1, Rf 0.61; IR
(neat, cm−1): 1263 (P O), 1449, 1495 (Ph), 1726
(C O), 1938 (C C C). 1H NMR (CDCl3, 600.1 MHz,
δ): 0.96 (t, J 7.3 Hz, 3H, Me(CH2)2), 1.62 (m, 2H,
MeCH2CH2), 2.37 (m, 2H, MeCH2CH2), 3.73, 3.80
(dd, J 11.3 Hz, 6H, 2MeO), 3.83 (s, 3H, MeO), 7.27–
7.55 (m, 5H, Ph). 13C NMR (CDCl3, 150.9 MHz, δ):
13.6 (CH3), 21.4 (J 6.8 Hz, CH2), 31.1 (J 4.3 Hz, CH2),
52.6 (CH3), 53.2, 53.4 (J 6.2 Hz, CH3), 98.7 (J 184.8
Hz, C), 104.6 (J 15.6 Hz, C), 128.3–131.1 (Ph), 165.8
(J 7.6 Hz, C), 214.6 (J 4.9 Hz, C). 31P NMR (CDCl3,
242.9 MHz, δ): 17.4. C16H21O5P (324.31). Calcd: C
59.26, H 6.53; found: C 59.18, H 6.60.
Hz, 3H, MeCH2O), 1.78 (s, 3H, Me), 3.63 (s, 1H, OH),
4.34 (q, J 7.1 Hz, 3H, MeCH2O), 7.28–7.45 (m, 5H,
Ph). 13C NMR (CDCl3, 150.9 MHz, δ): 14.5 (CH3),
27.3 (CH3), 63.1 (CH2), 68.4 (C), 83.9 (C), 88.4 (C),
122–131.7 (Ph), 173.3 (C). C13H14O3 (218.25). Calcd:
C 71.54, H 6.47; found: C 71.61, H 6.38.
Ethyl 2-hydroxy-2,4-diphenyl-but-3-ynoate (4f).
Orange crystals, yield: 75%. Eluent for TLC: ethyl ac-
etate:hexane = 1:4, Rf 0.80; mp 80–81◦C. The product
4f is a known compound whose spectroscopic prop-
erties were fully in accord with the reported one [23].
C18H16O3 (280.32). Calcd: C 77.12, H 5.75; found: C
77.20, H 5.69.
Heteroatom Chemistry DOI 10.1002/hc

328 Ivanov, Parushev, and Christov
Ethyl
4-(dimethoxyphosphoryl)-2-methyl-octa-
Ethyl 4-(diphenylphosphinoyl)-2-methyl-octa-2,3-
dienoate (8c). Yellow oil, yield: 60%. Eluent for
TLC: ethyl acetate:hexane = 1:1, Rf 0.61; IR (neat,
cm−1): 1121 (P O), 1439, 1488 (Ph), 1713 (C O),
1946 (C C C). 1H NMR (CDCl3, 600.1 MHz, δ): 0.85
(t, J 7.2 Hz, 3H, Me(CH2)3), 1.36 (t, J 7.1 Hz, 3H,
MeCH2O), 1.53 (d, J 8.8 Hz, 3H, Me), 2.31 (m, 2H,
Me(CH2)2CH2), 2.46 (m, 2H, Me(CH2)CH2), 4.23 (q,
2,3-dienoate (6c). Yellow oil, yield: 63%. Eluent for
TLC: ethyl acetate:hexane = 1:1, Rf 0.63; IR (neat,
cm−1): 1267 (P O), 1713 (C O), 1952 (C C C). 1H
NMR (CDCl3, 600.1 MHz, δ): 0.91 (t, J 7.3 Hz, 3H,
Me(CH2)3), 1.26 (t, J 7.1 Hz, 3H, MeCH2O), 1.39 (m,
2H, MeCH2(CH2)2), 1.49 (m, 2H, MeCH2CH2CH2),
1.94 (s, 3H, Me), 2.28 (m, 2H, MeCH2CH2CH2), 3.74
(d, J 11.2 Hz, 6H, 2MeO), 4.21 (q, J 7.1 Hz, 3H,
MeCH2O). 13C NMR (CDCl3, 150.9 MHz, δ): 13.8
(CH3), 14.2 (CH3), 14.4 (J 6.1 Hz, CH2), 21.9 (CH3),
28.4 (J 5.0 Hz, CH2), 30.0 (J 6.5 Hz, CH2), 53.1 (J 9.2
Hz, CH3), 61.4 (CH2), 96.0 (J 181.7 Hz, C), 97.6 (J
15.2 Hz, C), 166.7 (J 7.7 Hz, C), 213.2 (J 5.0 Hz, C).
31P NMR (CDCl3, 242.9 MHz, δ): 19.1. C13H23O5P
(290.29). Calcd: C 53.79, H 7.99; found: C 53.88,
H 8.05.
J 7.1 Hz, 3H, MeCH2O), 7.41–7.98 (m, 10H, 2Ph). 13
C
NMR (CDCl3, 150.9 MHz, δ): 13.7 (CH3), 13.9 (CH3),
14.5 (CH3), 22.8 (CH2), 27.4 (J 5.2 Hz, CH2), 30.4 (J
7.6 Hz, CH2), 61.3 (CH2), 98.1 (J 13.0 Hz, C), 102.4
(J 94.5 Hz, C), 128.5–132.7 (2Ph), 166.8 (J 4.3 Hz,
C), 212.4 (J 6.5 Hz, C). 31P NMR (CDCl3, 242.9 MHz,
δ): 31.8. C23H27O3P (382.43). Calcd: C 72.23, H 7.12;
found: C 72.30, H 7.21.
Methyl 4-(diphenylphosphinoyl)-2-phenyl-octa-
2,3-dienoate (8d). Orange oil, yield: 58%. Eluent for
TLC: ethyl acetate:hexane = 1:1, Rf 0.64; IR (neat,
cm−1): 1121 (P O), 1439, 1485 (Ph), 1726 (C O),
1931 (C C C). 1H NMR (CDCl3, 600.1 MHz, δ):
0.85 (t, J 7.4 Hz, 3H, Me(CH2)3), 1.33–1.39 (m, 4H,
Me(CH2)2CH2, 1.56–1.62 (m, 2H, Me(CH2)2CH2),
3.38 (s, 3H, MeO), 7.27–7.94 (m, 15H, 3Ph,). 13C
NMR (CDCl3, 150.9 MHz, δ): 13.8 (CH3), 15.0 (CH3),
22.3 (CH2), 27.8 (J 4.9 Hz, CH2), 30.3 (J 5.9 Hz,
CH2), 52.4 (CH3), 104.4 (J 92.9 Hz, C), 105.2 (J 12.9
Hz, C), 126.4–133.2 (3Ph), 165.8 (J 6.7 Hz, C), 213.3
(J 6.4 Hz, C). 31P NMR (CDCl3, 242.9 MHz, δ): 29.9.
C27H27O3P (430.48). Calcd: C 75.33, H 6.32; found:
C 75.41, H 6.25.
Ethyl
4-(dimethoxyphosphoryl)-2,4-diphenyl-
buta-2,3-dienoate (6f). Yellow oil, yield: 65%.
Eluent for TLC: ethyl acetate:hexane = 1:1, Rf 0.62;
IR (neat, cm−1): 1265 (P = O), 1447, 1493 (Ph), 1721
(C O), 1929 (C C C). 1H NMR (CDCl3, 600.1 MHz,
δ): 1.36 (t, J 7.1 Hz, 3H, MeCH2O), 3.84 (d, J 10.9
Hz, 6H, 2MeO), 4.36 (q, J 7.1 Hz, 2H, MeCH2O),
7.35–7.68 (m, 10H, 2Ph). 13C NMR (CDCl3, 150.9
MHz, δ): 14.3 (CH3), 53.6 (J 14.6 Hz, CH3), 61.8
(CH2), 101.6 (J 185.2 Hz, C), 105.9 (J 15.7 Hz, C),
127.8–129.2 (2Ph), 164.7 (C), 218.1 (J 4.7 Hz, C).
31P NMR (CDCl3, 242.9 MHz, δ): 15.6. C20H21O5P
(372.35). Calcd: C 64.51, H 5.68; found: C 64.43,
H 5.72.
Ethyl
4-(diphenylphosphinoyl)-2-methyl-4-
phenyl-buta-2,3-dienoate (8e). Orange oil, yield:
57%. Eluent for TLC: ethyl acetate:hexane = 1:1,
Rf 0.60; IR (neat, cm−1): 1179 (P O), 1439, 1487
General Procedure for Synthesis of the Alkyl
4-(Diphenylphosphinoyl)-alka-2,3-dienoates
(8c–f)
1
(Ph), 1714 (C O), 1940 (C C C). H NMR (CDCl3,
600.1 MHz, δ): 1.34 (t, J 7.1 Hz, 3H, MeCH2O), 1.56
(d, J 5.6 Hz, 3H, Me), 4.16–4.27 (m, 2H, MeCH2O),
7.22–7.97 (m, 15H, 3Ph). 13C NMR (CDCl3,
150.9 MHz, δ): 13.7 (J 4.8 Hz, CH3), 14.5 (CH3),
61.4 (CH2), 99.0 (J 12.3 Hz, C), 104.3 (J 95.4 Hz,
C), 128.1–132.4 (3Ph), 165.9 (J 6.4 Hz, C), 215.8
(J 5.9 Hz, C). 31P NMR (CDCl3, 242.9 MHz, δ): 30.6.
C25H23O3P (402.42). Calcd: C 74.62, H 5.76; found:
C 74.69, H 5.68.
To a solution of alkyl 2-hydroxy-alk-3-ynoates 4
(20 mmol) and triethylamine (2.23 g, 22 mmol) in dry
diethyl ether (60 mL) at –70◦C, a solution of freshly
distilled chlorodiphenylphosphine (4.41 g, 20 mmol)
in the same solvent (20 mL) was dropwise added
with stirring. The reaction mixture was stirred for
1 h at the same temperature and for 5 h at room tem-
perature. Then the mixture was washed with water,
2 N HCl, extracted with diethyl ether, and the extract
was washed with saturated NaCl, and dried over an-
hydrous sodium sulfate. The solvent was removed
using a rotatory evaporator, and the residue was
purified by column chromatography on a silica gel
(Kieselgel Merck 60 F254) with ethyl acetate/hexane
to give the pure products as oils, which had the fol-
lowing properties.
Ethyl
4-(diphenylphosphinoyl)-2,4-diphenyl-
buta-2,3-dienoate (8f). Orange oil, yield: 52%.
Eluent for TLC: ethyl acetate:hexane = 1:1, Rf 0.61;
IR (neat, cm−1): 1152 (P O), 1439, 1493 (Ph), 1717
(C O), 1921 (C C C). 1H NMR (CDCl3, 600.1
MHz, δ): 1.43 (t, J 6.9 Hz, 3H, MeCH2O), 4.35 (q,
J 6.9 Hz, 2H, MeCH2O), 7.20–7.95 (m, 20H, 4Ph).
Heteroatom Chemistry DOI 10.1002/hc

An Efficient Method for Regioselective Synthesis of 4-Heteroatom-Functionalized Allenecarboxylates 329
13C NMR (CDCl3, 150.9 MHz, δ): 14.5 (CH3), 61.6
(CH2), 106.1 (J 12.8 Hz, C), 107.2 (J 97.9 Hz, C),
127.8–132.4 (4Ph), 164.6 (C), 217.4 (J 7.1 Hz, C).
31P NMR (CDCl3, 242.9 MHz, δ): 29.6. C30H25O3P
(464.49). Calcd: C 77.57, H 5.42; found: C 77.49,
H 5.48.
Ethyl
4-(benzenesulfinyl)-2-methyl-octa-2,3-
dienoate (10c). Light yellow oil, yield: 67%. Eluent
for TLC: ethyl acetate:hexane = 1:4, Rf 0.62; IR
(neat, cm−1): 1057 (S O), 1440, 1475 (Ph), 1715
(C O), 1951 (C C C). 1H NMR (CDCl3, 600.1 MHz,
δ): 0.79 (t, J 6.9 Hz, 3H, Me(CH2)3), 1.34 (t, J 7.2 Hz,
3H, MeCH2O), 1.67 (m, 4H, Me(CH2)2CH2), 2.09
(s, 3H, Me), 2.35 (m, 2H, Me(CH2)2CH2), 4.28 (q, J
7.2 Hz, 3H, MeCH2O), 7.51–7.69 (m, 5H, Ph,). 13C
NMR (CDCl3, 150.9 MHz, δ): 14.3 (CH3), 15.0 (CH3),
15.8 (CH3), 22.5 (CH2), 25.2 (CH2), 29.9 (CH2), 68.4
(CH2), 108.9 (C), 115.4 (C), 132.6–148.4 (Ph), 166.4
(C), 213.7 (C). C17H22O3S (306.42). Calcd: C 66.63,
H 7.24; found: C 66.73, H 7.30.
General Procedure for Synthesis of the Alkyl
4-(Benzenesulfinyl)-alka-2,3-dienoates (10a–c,f)
To a solution of alkyl 2-hydroxy-alk-3-ynoates 4
(20 mmol) and triethylamine (2.23 g, 22 mmol) in dry
diethyl ether (60 mL) at –70◦C, a solution of freshly
distilled benzenesulfanyl chloride (2.89 g, 20 mmol)
in the same solvent (20 mL) was added dropwise
with stirring. The reaction mixture was stirred for
1 h at the same temperature and for 7 h at room
temperature. Then the mixture was washed with wa-
ter, 2 N HCl, extracted with ether, washed with sat-
urated NaCl, and dried over anhydrous sodium sul-
fate. After evaporation of the solvent, the residue was
chromatographed on a column (silica gel, Kieselgel
Merck 60 F254) with a mixture of ethyl acetate and
hexane as an eluent to give the pure products as yel-
low oils, which had the following properties.
Ethyl 4-(benzenesulfinyl)-2,4-diphenyl-buta-2,3-
dienoate (10f). Yellow oil, yield: 69%. Eluent for
TLC: ethyl acetate:hexane = 1:4, Rf 0.60; IR (neat,
cm−1): 1026 (S O), 1443, 1491 (Ph), 1719 (C O),
1947 (C C C). 1H NMR (CDCl3, 600.1 MHz, δ):
1.38 (t, J 6.8 Hz, 3H, MeCH2O), 4.36 (q, J 6.8 Hz,
2H, MeCH2O), 7.23–7.84 (m, 15H, 3Ph). 13C NMR
(CDCl3, 150.9 MHz, δ): 14.2 (CH3), 61.9 (CH2), 108.4
(C), 109.1 (C), 126.4–136.8 (3Ph), 167.8 (C), 216.0
(C). C24H20O3S (388.48). Calcd: C 74.20, H 5.19;
found: C 74.16, H 5.27.
Ethyl
4-(benzenesulfinyl)-2-methyl-hepta-2,3-
General Procedure for Synthesis of the Alkyl
dienoate (10a). Yellow oil, yield: 64%. Eluent for
TLC: ethyl acetate:hexane = 1:1, Rf 0.59; IR (neat,
cm−1): 1051 (S O), 1445, 1476 (Ph), 1715 (C O),
1951 (C C C). 1H NMR (CDCl3, 250.1 MHz, δ):
1.00 (t, J 7.5 Hz, 3H, Me(CH2)2), 1.33 (t, J 7.2
Hz, 3H, MeCH2O), 1.52 (m, 2H, MeCH2CH2), 2.02
(s, 3H, Me), 2.23 (m, 2H, MeCH2CH2), 4.24 (m,
2H, MeCH2O), 7.46–7.80 (m, 5H, Ph). 13C NMR
(CDCl3, 62.9 MHz, δ): 13.3 (CH3), 13.5 (CH3), 14.4
(CH3), 20.7 (CH2), 26.9 (CH2), 61.6 (CH2), 102.9 (C),
115.8 (C), 124.6–131.4 (Ph), 166.0 (C), 206.8 (C).
C16H20O3S (292.39). Calcd: C 65.72, H 6.89; found:
C 65.82, H 6.95.
4-(methanesulfonyl)-alka-2,3-dienoates (12c–f)
To a solution of alkyl 2-hydroxy-alk-3-ynoates 4
(20 mmol) and triethylamine (2.23 g, 22 mmol) in dry
diethyl ether (60 mL) at –70◦C, a solution of freshly
distilled methanesulfinyl chloride (1.97 g, 20 mmol)
in the same solvent (20 mL) was added dropwise
with stirring. The reaction mixture was stirred for
1 h at the same temperature and for 2 h at room
temperature. Then the mixture was washed with wa-
ter, 2 N HCl, extracted with ether, washed with sat-
urated NaCl, and dried over anhydrous sodium sul-
fate. After evaporation of the solvent, the residue was
dissolved in dried toluene (30 mL) and refluxed for
8 h. After evaporation of the solvent, the residue was
chromatographed on a column (silica gel, Kieselgel
Merck 60 F254) with a mixture of ethyl acetate and
hexane as an eluent to give the pure products as oils,
which had the following properties.
Methyl
4-(benzenesulfinyl)-2-phenyl-hepta-2,3-
dienoate (10b). Yellow oil, yield: 64%. Eluent for
TLC: ethyl acetate:hexane = 1:4, Rf 0.62; IR (neat,
cm−1): 1053 (S O), 1434, 1495 (Ph), 1728 (C O),
1943 (C C C). 1H NMR (CDCl3, 600.1 MHz, δ):
0.83 (t, J 7.3 Hz, 3H, Me(CH2)2), 1.48 (m, 2H,
MeCH2CH2), 2.33 (m, 2H, MeCH2CH2), 3.72 (s, 3H,
MeO), 7.22–8.23 (m, 10H, 2Ph,). 13C NMR (CDCl3,
150.9 MHz, δ): 12.1 (CH3), 19.4 (CH2), 31.4 (CH2),
52.7 (CH3), 106.3 (C), 111.1 (C), 122.6–146.5 (2Ph),
161.9 (C), 209.5 (C). C20H20O3S (340.44). Calcd: C
70.56, H 5.92; found: C 70.65, H 6.01.
Ethyl
4-(methanesulfonyl)-2-methyl-octa-2,3-
dienoate (12c). Light orange oil, yield: 48%. Eluent
for TLC: ethyl acetate:hexane = 1:1, Rf 0.61; IR
(neat, cm−1): 1144, 1314 (SO2), 1719 (C O), 1960
(C C C). 1H NMR (CDCl3, 600.1 MHz, δ): 0.95
(t, J 7.3 Hz, 3H, Me(CH2)3), 1.30 (t, J 7.1 Hz, 3H,
MeCH2O), 1.46 (m, 2H, MeCH2CH2CH2), 1.58 (m,
Heteroatom Chemistry DOI 10.1002/hc

330 Ivanov, Parushev, and Christov
Academic Press: London, 1982, Vol. 1–3; (c) Pasto,
D. J. Tetrahedron 1984, 40, 2805–2827; (d) Schus-
ter, H. F.; Coppola, G. M. Allenes in Organic Synthe-
sis; Wiley: New York, 1988; (e) Zimmer, R. Synthesis
1993, 165–178; (f) Elsevier, C. J. In Methods of Or-
ganic Chemistry (Houben–Weyl); Helmchen, R. W.;
Mulzer, J.; Schaumann, E. (Eds.); Thieme: Stuttgart,
Germany, 1995; Vol. E21a, 537–566; (g) Krause, N.;
Hashmi, A. S. K. (Eds.). Modern Allene Chemistry;
Wiley-VCH: Weinheim, Germany, 2004, Vol. 1 & 2;
(h) Brummond, K. M.; DeForrest, J. E. Synthesis
2007, 795–818. DOI:10.1055/s-2007-965963.
2H, MeCH2CH2CH2), 2.07 (s, 3H, Me), 2.52 (m, 2H,
Me(CH2)2CH2), 3.46 (s, 3H, MeSO2), 4.26 (q, J 7.1
Hz, 3H, MeCH2O). 13C NMR (CDCl3, 150.9 MHz, δ):
13.9 (CH3), 14.4 (CH3), 14.9 (CH3), 28.6 (CH2), 33.8
(CH2), 36.5 (CH2), 49.2 (CH3), 68.8 (CH2), 111.4 (C),
115.5 (C), 165.2 (C), 216.1 (C). C12H20O4S (260.35).
Calcd: C 55.36, H 7.74; found: C 55.28, H 7.79.
Methyl
4-(methanesulfonyl)-2-phenyl-octa-2,3-
dienoate (12d). Light yellow oil, yield: 47%. Eluent
for TLC: ethyl acetate:hexane = 1:3, Rf 0.65; IR
(neat, cm−1): 1142, 1315 (SO2), 1450, 1488 (Ph),
1726 (C O), 1947 (C C C). 1H NMR (CDCl3, 250.1
MHz, δ): 0.91 (t, J 7.2 Hz, 3H, Me(CH2)3), 1.40 (m,
2H, MeCH2CH2CH2), 1.58 (m, 2H, MeCH2CH2CH2),
2.58 (m, 2H, Me(CH2)2CH2), 3.08 (s, 3H, MeSO2),
3.88 (s, 3H, MeO), 7.35–7.58 (m, 5H, Ph). 13C NMR
(CDCl3, 62.9 MHz, δ): 13.7 (CH3), 22.1 (CH2), 27.3
(CH2), 29.5 (CH2), 42.4 (CH3), 53.0 (CH3), 110.8 (C),
117.4 (C), 128.4–130.2 (Ph), 164.7 (C), 210.4 (C).
C16H20O4S (308.39). Calcd: C 62.31, H 6.54; found:
C 62.23, H 6.47.
[2] (a) Bates, R. W.; Satcharoen, V. Chem Soc Rev 2002,
31, 12–21; (b) Petrov, P. Y.; Angelov, C. M.; Petrov,
G.; Alexiev, A.; Cavell, R. G. Heteroat Chem 2004, 15,
413–417; (c) Ma, S. Aldrichim Acta 2007, 40, 91–102;
(d) Hassan, H. H. A. M. Curr Org Synth 2007, 4, 413–
439; (e) Petrov, P. Y.; Angelov, C. M.; McDonald, R.;
Alexiev, A.; Cavell, R. G. Heteroat Chem 2010, 21,
196–202; (f) Back, T. G.; Clary, K. N.; Gao, D. Chem
Rev 2010, 110, 4498–4553.
[3] (a) Bestmann, H. J.; Hartung, H. Angew Chem, Int
Ed Engl 1963, 2, 214–215; (b) Aksnes, G.; Froeyen, P.
Acta Chem Scand 1968, 22, 2347–2347; (c) Lang, R.
W.; Hansen, H.-J. Helv Chim Acta 1980, 63, 438–455.
[4] Fillion, H.; Hseine, A.; Pera, M.-H.; Dufaud, V.; Re-
fouvelet, B. Synthesis 1987, 708–709. DOI:10.1055/s-
1987-28052.
Ethyl
4-(methanesulfonyl)-2-methyl-4-phenyl-
[5] Tanaka, K.; Otsubo, K.; Fuji, K. Synlett 1995, 933.
DOI:10.1055/s-1995-5140.
[6] Li, C.-Y.; Wang, X.-B.; Sun, X.-L.; Tang, Y.; Zheng,
J.-C.; Xu, Z.-H.; Zhou, Y.-G.; Dai, L.-X. J Am Chem
Soc 2007, 129, 1494–1495.
[7] Miesch, M. Synthesis 2003, 746–752 and references
cited therein. DOI:10.1055/s-2004-815983.
buta-2,3-dienoate (12e). Light orange oil, yield:
46%. Eluent for TLC: ethyl acetate:hexane = 1:1, Rf
0.59; IR (neat, cm−1): 1140, 1311 (SO2), 1447, 1489
1
(Ph), 1722 (C O), 1951 (C C C). H NMR (CDCl3,
600.1 MHz, δ): 1.33 (t, J 7.1 Hz, 3H, MeCH2O), 2.10
(s, 3H, Me), 3.00 (s, 3H, MeSO2), 4.30 (q, J 7.1 Hz,
3H, MeCH2O), 7.27–7.64 (m, 5H, Ph). 13C NMR
(CDCl3, 150.9 MHz, δ): 14.3 (CH3), 14.7 (CH3), 42.7
(CH3), 62.3 (CH2), 111.5 (C), 116.5 (C), 128.1–129.8
(Ph), 165.3 (C), 212.3 (C). C14H16O4S (280.34).
Calcd: C 59.98, H 5.75; found: C 60.06, H 5.69.
[8] (a) Mark, V. In The Uncatalyzed Rearrangements
of Tervalent Phosphorus Esters in Selective Organic
Transformations; Thyagarajan, B. S. (Ed.); Wiley:
New York, 1970; pp. 319–437; (b) Landor, P. D. In
The Chemistry of the Allenes; Landor, S. R. (Ed.);
Academic Press: New York, 1982; Vol. 1, pp. 174–
178; (d) Saalfrank, R. W.; Lurz, C.-J. In Methoden
der Organischen Chemie (Houben Weyl); Kropf, H.;
Scheumann, E. (Eds.); Thieme: Stuttgart, Germany,
1993; pp. 2959–3102; (e) Hashmi, A. S. K. In Synthe-
sis of Allenes in Modern Allene Chemistry; Krause,
N.; Hashmi, A. S. K. (Eds.); Wiley-VCH: Weinheim,
Germany, 2004; Vol. 1, pp. 3–50.
[9] (a) Pudovik, A. N.; Aladjeva, I. M. J Gen Chem
1963, 33, 700–706; (b) Macomber, R. S. J Am
Chem Soc 1977, 99, 3072–3075; (c) Denmark, S.
E.; Marlin, J. E. J Org Chem 1991, 56, 1003–1013;
(d) Cai, B.; Blackburn, G. M. Synth Commun
1997, 27, 3943–3949; (e) Saalfrank, R. W.; Haub-
Ethyl 4-(methanesulfonyl)-2,4-diphenyl-buta-2,3-
dienoate (12f). Orange oil, yield: 52% (54%, in the
case of isolation by column chromatography of 11f).
Eluent for TLC: ethyl acetate:hexane = 1:3, Rf 0.60;
IR (neat, cm−1): 1140, 1315 (SO2), 1447, 1493 (Ph),
1724 (C O), 1942 (C C C). 1H NMR (CDCl3, 600.1
MHz, δ): 1.38 (t, J 7.1 Hz, 3H, MeCH2O), 3.07 (s,
3H, Me), 4.38 (q, J 7.2 Hz, 3H, MeCH2O), 7.26–7.84
(m, 5H, 2Ph,). 13C NMR (CDCl3, 150.9 MHz, δ): 14.5
(CH3), 42.8 (CH3), 62.5 (CH2), 110.7 (C), 117.4 (C),
126.8–132.6 (2Ph), 163.5 (C), 213.9 (C). C19H18O4S
(342.41). Calcd: C 66.65, H 5.30; found: C 66.57, H
5.35.
ner, M.; Deutscher, C.; Bauer, U. Eur
J Org
Chem 1999, 2367–2372. DOI:10.1002/(SIC)1099-
0690(199909)1999:9<2367::AID-EJOC2367>3.0.CO;
2-9.
[10] (a) Boiselle, A. P.; Meinhardt, N. A. J Org Chem 1962,
27, 1828–1833; (b) Mark, V. Tetrahedron Lett 1962,
3, 281–284; (c) Sevin, A.; Chodkiewicz, W. Bull Soc
Chim Fr 1969, 36, 4016–4021; (d) Ignatev, V. M.; Tim-
ofeeva, T. N.; Ionin, B. I.; Petrov, A. A. J Gen Chem
1969, 39, 1567–1572.
REFERENCES
[1] (a) Patai, S. (Ed.). The Chemistry of Ketenes, Allenes
and Related Compounds; Wiley: New York, 1980;
(b) Landor, S. R. (Ed.). The Chemistry of the Allenes;
[11] (a) Nicolaou, K. C.; Maligres, P.; Shin, J.; de
Leon, E.; Rideout, D. J Am Chem Soc 1990, 112,
Heteroatom Chemistry DOI 10.1002/hc

An Efficient Method for Regioselective Synthesis of 4-Heteroatom-Functionalized Allenecarboxylates 331
7825–7826; (b) Curfin, M. L.; Okamura, W. H. J
lat Elem 2000, 166, 243–249; (d) Christov, V. Ch.;
Prodanov, B. Heterocycl Commun 2002, 8, 349–354;
(e) Christov, V. Ch.; Prodanov, B. Heterocycles 2002,
57, 1777–1780; (f) Christov, V. Ch.; Prodanov, B.
Synth Commun 2004, 34, 1577–1588; (g) Christov,
V. Ch.; Ivanova, J. G. Synth Commun 2006, 36,
2231–2244; (h) Ivanov, I. K.; Christov, V. Ch. Phos-
phorus, Sulfur Silicon Relat Elem 2013, in press,
DOI:10.1080/10426507.2012.718299.
Org Chem 1990, 55, 5278–5287; (c) Grissom, J. W.;
Huang, D. Angew Chem, Int Ed 1995, 34, 2037–2039;
(d) Darcel, C.; Bruneau, C.; Dixneuf, P. H. Synthesis
1996, 711–714; (e) de Frutos, O.; Echavarren, A. M.
Tetrahedron Lett 1997, 38, 7941–7943; (f) Schmittel,
M.; Steffen, J.-P.; Maywald, M.; Engels, B.; Helten, H.;
Musch, P. J Chem Soc, Perkin Trans 2 2001, 1331–
1342. DOI:10.1039/B102380M.
[12] (a) Horner, L.; Binder, V. Liebigs Ann Chem 1972,
757, 33–68; (b) Baudin, J.-B.; Julia, S. A.; Wang, Y.
Tetrahedron Lett 1989, 30, 4965–4968; (c) Baudin,
J.-B.; Bkouche-Waksman, I.; Julia, S. A.; Pascard,
C.; Wang, Y. Tetrahedron 1991, 47, 3353–3364;
(d) Wang, X.; Ni, Z.; Lu, X.; Hollis, A.; Banks, H.;
Rodriguez, A.; Padwa, A. J Org Chem 1993, 58, 5377–
5385.
[13] (a) Braverman, S.; Mechoulam, H. Israel J Chem
1967, 5, 71–75; (b) Smith, G.; Stirling, C. J. M. J Chem
Soc C 1971, 1530–1535. DOI:10.1039/J39710001530;
(c) Braverman, S.; van Asten, P. F. T. M.; van der Lin-
den, J. B.; Zwanenburg, B. Tetrahedron Lett 1991,
31, 3867–3870.
[14] (a) Braverman, S. In The Chemistry of Sulphones
and Sulphoxides; Patai, S.; Rappoport, Z.; Stirling,
C. J. M. (Eds.); Wiley: New York, 1988; Ch. 13, pp.
665–716; (b) Braverman, S. In The Chemistry of Sul-
phones and Sulphones; Patai, S.; Rappoport, Z.; Stir-
ling, C. J. M. (Eds.); Wiley: New York, 1988; Ch. 14,
pp. 717–757.
[15] (a) Conrads, M.; Mattay, J. Synthesis 1991, 11–14.
DOI:10.1055/s-1991-26365; (b) Padwa, A.; Bullock,
W. H.; Norman, B. H.; Perumattam, J. J Org Chem
1991, 56, 4252–4259.
[17] (a) Metcalf, B. W.; Wright, C. L.; Burkhart, J. P.;
Johnston, J. O. J Am Chem Soc 1981, 103, 3221–
3222; (b) Muller, M.; Mann, A.; Taddei, M. Tetra-
hedron Lett 1993, 34, 3289–3290; (c) Brel, V.
K.; Stang, P. J. Eur J Org Chem 2003, 224–229.
DOI:10.1002/1099-0690(200301)2003:1<224::AID-
EJOC224>3.0.CO;2-3; (d) Brel, V. K. Synthesis 2001,
1539–1545. DOI:10.1055/s-2001-16078; (e) Brel,
V. K.; Belsky, V. K.; Stash, A. I.; Zvodnik, V. E.;
Stang, P. J. Org Biomol Chem 2003, 1, 4220–4226;
(f) Brel, V. K.; Belsky, V. K.; Stash, A. I.; Zvodnik,
V. E.; Stang, P. J. Eur J Org Chem 2005, 512–521.
DOI:10.1002/ejoc.200400523.
[18] (a) Christov, V. Ch.; Ivanov, I. K. Phosphorus, Sulfur
Silicon Relat Elem 2002, 177, 2445–2454; (b) Chris-
tov, V. Ch.; Ivanov, I. K. Sulfur Lett 2002, 25, 191–198.
[19] (a) Christov, V. Ch.; Ivanov, I. K. Heterocycl Com-
mun 2003, 9, 629–634; (b) Christov, V. Ch.; Ivanov, I.
K. Phosphorus, Sulfur Silicon Relat Elem 2004, 179,
1681–1690.
[20] (a) Ivanov, I. K.; Christov, V. Ch. Heteroatom Chem
2012, 23, 345–351; (b) Ivanov, I. K.; Christov, V. Ch.
Synth Commun 2013, 43, 800–809.
[21] White, W. L.; Ricciardelli, K. L.; Chaguturu, M. K. US
patent 4704161, 1987.
[16] Previous our reports on the chemistry of bi-
functionalized allenes, see: (a) Christov, V. Ch.;
Prodanov, B. Phosphorus, Sulfur Silicon Relat
Elem 2000, 166, 265–273; (b) Christov, V. Ch.;
Prodanov, B.; Nikolova, R. Phosphorus, Sulfur Sil-
icon Relat Elem 2000, 166, 275–281; (c) Christov,
V. Ch.; Prodanov, B. Phosphorus, Sulfur Silicon Re-
[22] Baum, B. M.; Stange, H. US patent 4 465 834, 1984.
[23] Meyer, A.; Flammang, M.; Wermuth, C. G. Synthesis,
1976, 832–833.
[24] Lecher, H.; Holschneider, F. Ber Dtsch Chem Ges
1924, 57, 755–758.
[25] Youn, J.-H.; Herrman, R. Tetrahedron Lett 1986, 27,
1493–1494.
Heteroatom Chemistry DOI 10.1002/hc