Synthesis, including asymmetric synthesis, of 1-substituted cyclopentenes from cyclobutanones with one-carbon ring-expansion by 1,2-carbon-carbon insertion of magnesium carbenoids

Article abstract of DOI:10.1016/j.tet.2010.12.023

Treatment of 1-chlorovinyl p-tolyl sulfoxides, which were derived from cyclobutanones and chloromethyl p-tolyl sulfoxide, with lithium enolate of tert-butyl carboxylates, amides, lithium α-sulfonyl carbanions, and lithium α-carbanion of acetonitrile gave

Full text of DOI:10.1016/j.tet.2010.12.023

Tetrahedron 67 (2011) 1102e1113
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Synthesis, including asymmetric synthesis, of 1-substituted cyclopentenes from
cyclobutanones with one-carbon ring-expansion by 1,2-carbon-carbon insertion
of magnesium carbenoids
*
Tsuyoshi Satoh , Yu Awata, Yuichi Kato, Shingo Ogata, Masashi Ishigaki, Shimpei Sugiyama, Hideki Saitoh
Graduate School of Chemical Sciences and Technology, Tokyo University of Science; Ichigaya-funagawara-machi 12, Shinjuku-ku, Tokyo 162-0826, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
Treatment of 1-chlorovinyl p-tolyl sulfoxides, which were derived from cyclobutanones and chloromethyl
Received 15 November 2010
Received in revised form 9 December 2010
Accepted 9 December 2010
Available online 15 December 2010
p-tolyl sulfoxide, with lithium enolate of tert-butyl carboxylates, amides, lithium
a-sulfonyl carbanions, and
lithium -carbanion ofacetonitrilegave adducts in high toquantitativeyields. The adductsweretreated with
a
Grignard regents, such as i-PrMgCl and EtMgCl in toluene to afford 1-substituted cyclopentenes in good to
high yields with one-carbon ring-expansion via 1,2-carbonecarbon (1,2-CC) insertion reaction of the gen-
erated magnesium carbenoid intermediates. The magnesium carbenoid 1,2-CC insertion was found to be
highly stereospecific. When optically pure chloromethyl p-tolyl sulfoxide was used in this procedure, opti-
cally active 1-substituted cyclopentenes were obtained in high optical purity.
Keywords:
Cyclopentene
Magnesium carbenoid
1,2-Carbonecarbon insertion
One-carbon ring-expansion
Rearrangement
Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction
Ring enlargement of carbocyclic compounds is one of the most
useful and important methods for obtaining the desired carbocycles
from lower carbocycles with carbon homologation.1 One-carbon
Cl
S(O)Tol
Nu
O
TolS(O)CH2Cl
R1
Nu
( )
-
Cl
ring-expansion of cyclic ketones by the rearrangement of b-oxido
R1
R1
( )n
( )n
carbenoid as the key reaction has long been investigated by Norm-
ant,2 Kobrich,3 Yamamoto,4 Hiyama,5 and Cohen.6 We alsohavebeen
interested in homologation of carbonyl compounds, including one-
carbon ring-expansion of cyclic ketones, by the rearrangement of
n S(O)Tol
Nu
2
1
3
Nu
Cl
magnesium b
-oxido carbenoids as the key reaction.7
n is 2 or more
RMgCl
MgCl
R1
R1
In keeping with our ongoing interest in the chemistry and
synthetic uses of magnesium carbenoids,8 we recently reported the
synthesis of bicyclo[n.1.0]alkanes 5 (n is 2 or more) from cyclo-
alkanones 1 (n is 2 or more) by 1,3-carbonehydrogen (1,3-CH) in-
sertion of magnesium carbenoid intermediates 4 (n is 2 or more),9
which were generated from the adducts 3 with a Grignard reagent
via sulfoxideemagnesium exchange reaction (Scheme 1).8 Quite
interestingly, when this reaction was carried out with the adducts 3
(n¼1), which were derived from cyclobutanones 1 (n¼1) via
1-chlorovinyl p-tolyl sulfoxides 2 (n¼1), we obtained 1-substituted
cyclopentenes 6, instead of the expected bicyclo[2.1.0]pentane de-
rivatives 5 (n¼1), in good to high yields.
( )n
( )n
1,3-CH insertion
Lit. 9
4
5
R1
n = 1
Nu
1,2-CC insertion
This work
6
-
t
= LiCH(R)COO Bu, LiCH(R)CON(CH3)2,
Nu
LiCH(R)SO2Ph, LiCH2CN
Scheme 1.
* Corresponding author. E-mail address: tsatoh@rs.kagu.tus.ac.jp (T. Satoh).
0040-4020/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2010.12.023

T. Satoh et al. / Tetrahedron 67 (2011) 1102e1113
1103
Obviously, instead of the expected 1,3-CH insertion, 1,2-carbone
carbon (1,2-CC) insertion of the generated magnesium carbenoid
intermediates 4 took place to afford one-carbon ring-expanded cy-
clic olefins 6. Release of the ring-strains of cyclobutanes is presumed
to be the driving force of this reaction. As we recognized that this
reaction is very useful for the synthesis of 1-substituted cyclo-
pentenes 6 by assemblage of three components, cyclobutanones,
chloromethyl p-tolyl sulfoxide, and nucleophiles, we further in-
vestigated this reaction. Moreover, the synthesis of optically active
1-substituted cyclopentenes would be expected if optically active
chloromethylp-tolylsulfoxidewas used in this procedure. Wereport
here, in detail, a synthesis, including asymmetric synthesis, of
cyclopentenes bearing esters, amides, sulfones, and nitriles at 1-
position 6 from cyclobutanones with one-carbon ring-expansion via
1-chlorovinyl p-tolyl sulfoxides 2 and magnesium carbenoids 4 by
the 1,2-CC insertion as the key reaction.10
to be a cyclopentene bearing a tert-butyl acetate moiety at the 1-
position 11 on the bases of IR, NMR, and MS spectral data. Obviously,
the product was produced bymagnesiumcarbenoid 1,2-CC insertion
reaction, instead of the expected 1,3-CH insertion. To the best of our
knowledge, this isthe firstexampleofone-carbonring-expansionby
the magnesium carbenoid 1,2-CC insertion reaction.
Next, we investigated the optimum conditions of this reaction
and the results are summarized in Table 1. Using 3 equiv of i-PrMgCl
in this reaction resulted in better yield (54%); however, some
amount of the starting material 9 still remained (entry 2). When
5 equiv of i-PrMgCl was used, all the starting material disappeared
and the yield of product 11 was improved (entry 3). Worse results
were obtained when this reaction was started with higher reaction
temperature (ꢀ40 or 0 ꢁC) (entries 4 and 5). Selection of THF as
a solvent gave a similar result (compare the results in entry 3 and 6).
Dichloromethane was proved to be unsuitable solvent (entry 7). We
concluded that the conditions in entry 3 are suitable for the reaction.
Inordertoinvestigate thegeneralityof thesereactions, wefurther
studied this procedure starting with 1-chlorovinyl p-tolyl sulfoxides
(8,12, and 13) and a few tert-butyl carboxylates under the conditions
described above, and the results are summarized in Table 2. The
addition reaction of vinyl sulfoxide 8 with lithium enolate of tert-
butyl propionate and tert-butyl 4-phenylbutyrate proceeded
smoothly to give adducts 14a and 14b, respectively, in up to 99% yield
(entries 1 and 2). Treatment of these adducts 14a and 14b with
5 equiv of i-PrMgCl resulted in the formation of the desired cyclo-
pentenes 15a and 15b, respectively, in high to quantitative yields.
The addition reaction of 12 with tert-butyl carboxylates again gave
adducts 14cee in up to 99% yield (entries 3e5). The key reaction was
conducted smoothly to give the desired cyclopentenes 15cee in up to
91% yield without any problem. Entries 6e9 show the results starting
from cyclobutanoneitself. Addition reaction of vinyl sulfoxide13 with
lithium enolate of tert-butyl carboxylates including tert-butyl (4-
methylphenyl)acetate gave adducts 14fei all in quantitative yields.
Treatment of these four adducts with i-PrMgCl resulted in the for-
mation of the desired cyclopentenes 15fei in somewhat variable
2. Results and discussion
2.1. Synthesis of cyclopentenes bearing a tert-butyl
carboxylate moiety at the 1-position
Representative example of this study starting from cyclo-
butanone 7 is reported (see Table 1). Thus, 3,3-bis(ethoxymethyl)-1-
[chloro(p-tolylsulfinyl)methylidene]cyclobutane 8 was synthesized
from 7 in three steps in good overall yield.11 Treatment of 8 with
lithium enolate of tert-butyl acetate at ꢀ78 ꢁC afforded adduct 9 in
quantitative yield.12 In expecting of the formation of bicyclo[2.1.0]
pentane derivative by 1,3-CH insertion of the generated magnesium
carbenoid intermediate 10, as described above,9 a solution of the
adduct 9 was added to a solution of 2 equiv of i-PrMgCl in toluene at
ꢀ78 ꢁC and the temperature of the reaction mixture was slowly
allowed to warm to 0 ꢁC for 2 h (entry 1, Table 1).
Table 1
Synthesis of cyclopentene bearing a tert-butyl acetate moiety at 1-position 11 from
cyclobutanone 7 with one-carbon ring-expansion via 1,2-CC insertion of magnesium
carbenoid intermediate 10
yields. It is worth noting that the aromatic ring at the a-position of the
ester group did not affect the key reaction, 1,2-CC insertion (entry 9).
From these results, generality of this procedure was verified.
TolS(O)CH2Cl
Cl
EtO
EtO
EtO
EtO
O
in three steps
85%
Later, we found that the tert-butyl carboxylate group was not
essential in the 1,2-CC insertion reaction (see Scheme 2). Thus, ether
16 was derived from adduct 9 by treatment with diisobutylaluminum
hydride followed by p-methoxybenzyl chloride. Ether 16 was treated
with i-PrMgCl in the same conditions as described above to afford the
desired cyclopentene 17 in a similar yield without any problem.
Next, we investigated this procedure starting from an un-
symmetrical cyclobutanone and observed very interesting stereo-
specificity of the 1,2-CC insertion (Scheme 3). Thus, unsymmetrical
cyclobutanone 18 was synthesized from cyclopropyl phenyl sul-
fide,13 which was converted into 1-chlorovinyl p-tolyl sulfoxide 19
in three steps in 42% overall yield as a mixture of two geometrical
isomers. The geometrical isomers of the vinyl sulfoxides were
separated by silica gel column chromatography to give E-isomer
19a and Z-isomer 19b in a ratio of 21:79. Determination of the
stereochemistry of the vinyl sulfoxides was reported previously.10
Treatment of both vinyl sulfoxides 19a and 19b with lithium
enolate of tert-butyl acetate afforded adducts 20a and 20b, re-
spectively, both as a single isomer with high stereospecificity in good
yields. Relative stereochemistry of the adducts was determined to be
as shown in Scheme 3 based on our previous study.14 At first, the
sulfoxideemagnesium exchange reaction of 20awas conducted with
i-PrMgCl; however, noreactionwasobserved. Steric hindrance bythe
2-phenylethyl group on the cyclobutane ring was thought to be the
reason for this difficulty. Fortunately, 20a reacted smoothly with
EtMgCltoaffordthedesiredcyclopentenebearingatert-butylacetate
moiety 22a in 40% yield as a single product. The same treatment of
S(O)Tol
8
7
t
t
LiCH2COO Bu
COO Bu
i-PrMgCl
Conditions
EtO
EtO
S(O)Tol
THF, -78 °C, 15 min
99%
Cl
9
1,2-CC
insertion
t
EtO
EtO
t
COO Bu
COO Bu
EtO
EtO
MgCl
Cl
10
11
Entry
i-PrMgCl
Conditions
11
equiv
Temp/ꢁC
Time/h
Solvent
Yield/%
1
2
3
4
5
6
7
2
3
5
5
5
5
5
ꢀ78e0
ꢀ78e0
ꢀ78e0
ꢀ40e0
0
2
2
2
1
0.5
2
2
Toluene
Toluene
Toluene
Toluene
Toluene
THF
35a
54a
73
51
54
70
45
ꢀ78e0
ꢀ78e0
CH2Cl2
a
Some amount of the starting material 9 was recovered.
Although significant amount of the starting material remained,
the reaction mixture was rather clean and a product was obtained.
Very interestingly, the product had an olefinic hydrogen (1H NMR
d 5.38,1H, br s) and no hydrogen on the cyclopropane ring
was observed. Finally, the structure of the product was determined
spectrum;

1104
T. Satoh et al. / Tetrahedron 67 (2011) 1102e1113
Table 2
Synthesis of cyclopentenes bearing a tert-butyl carboxylate moiety at 1-position 15 from 1-chlorovinyl p-tolyl sulfoxides 8, 12, and 13 via adducts 14 with one-carbon ring-
expansion by 1,2-CC insertion of magnesium carbenoid intermediates
R2
R2
R1
t
R2CH2COO Bu (5 eq)
R1
R1
t
t
R1
R1
COO Bu
COO Bu
Cl
i-PrMgCl (5 eq)
R1
S(O)Tol
S(O)Tol
Toluene, -78 ~ 0 °C
LDA / THF, -78 °C, 15 min
Cl
14
8 R1 = CH2OC2H5
15
12 R1 = CH2O(CH2)3Ph
13 R1 = H
Entry
1-Chlorovinyl p-tolyl sulfoxide
14
15
R1
R2
Yield/%
Yield/%
1
2
3
4
5
6
7
8
8
8
CH2OC2H5
CH2OC2H5
CH2O(CH2)3Ph
CH2O(CH2)3Ph
14a
14b
14c
14d
14e
14f
CH3
CH2CH2Ph
H
CH3
CH2CH2Ph
H
86
99
94
99
89
99
99
99
15a
15b
15c
15d
15e
15f
97
89
75
84
91
77
70
98
12
12
12
13
13
13
CH2O(CH2)3Ph
H
H
H
14g
14h
CH3
CH2CH2Ph
15g
15h
9
13
H
14i
99
15i
92
CH3
1) DIBAL-H (5 eq)
Toluene, 0 °C, 10 min, 90%
CH2CH2Ph
Cl
t
CH2CH2Ph
COO Bu
EtO
EtO
TolS(O)CH2Cl
3
S(O)Tol
O
in three steps
42%
( E : Z = 21 : 79 )
OCH3
Cl
2) ClCH2
S(O)Tol
18
19
9
AcOEt, Ag2O, reflux, 37%
O
t
i-PrMgCl (5 eq)
CH2CH2OCH2-
S(O)Tol
O Bu
OCH3
CH2CH2Ph
PhCH2CH2
EtO
EtO
S(O)Tol
Toluene,
-78 ~ 0 °C,
92%
t
EtMgCl (5 eq)
LiCH2COO Bu
Cl
16
Cl
S
Tol
Cl
S*
Toluene,
-78 ~ 0 °C
40%
THF, -78 °C, 15 min
74%
O
19a
20a
EtO
EtO
CH2CH2OCH2-
OCH3
t
CH2CH2Ph
O Bu
t
PhCH2CH2
COO Bu
17
Mg
O
R*
Scheme 2.
Cl
22a
Cl
21a
the diastereomer 20b with EtMgCl gave the structural isomer 22b in
61% again as a single product. Quite interestingly, these reactions are
highly stereospecific. Determination of the structure of the two
products (22a and 22b) was reported in the preliminary letter.10
The mechanism of this interesting and highly stereospecific
magnesium carbenoid 1,2-CC insertion reaction can be explained as
follows. As the sulfoxideemagnesium exchange reaction is known
to proceed with retention of the configuration of the carbon bear-
ing the sulfinyl group,15 treatment of 20a with EtMgCl gives mag-
PhCH2CH2
O
CH2CH2Ph
Cl
t
O Bu
t
LiCH2COO Bu
EtMgCl (5 eq)
THF, -78 °C,
15 min, 81%
Toluene,
-78 ~ 0 °C
61%
S(O)Tol
Cl
S
Tol
S*
19b
O
nesium carbenoid having R -configuration at the carbon bearing
*
20b
PhCH2CH2
the magnesium atom. The magnesium and carbonyl oxygen atom
of the tert-butyl ester group must make six-membered in-
termediate 21a,14 in which the bulkiest tert-butoxy group would
occupy the equatorial-like position. From this intermediate, the 1,2-
CC insertion takes place from behind of the carbonechlorine bond
to give the product 22a. The situation of the reaction of 20b with
EtMgCl is thought to be similar. The magnesium carbenoid in-
termediate derived from 20b must make the six-membered in-
termediate 21b and again the 1,2-CC insertion reaction proceeds
from behind of the carbonechlorine bond to afford 22b.
CH2CH2Ph
t
O Bu
Mg
O
Cl
R*
t
COO Bu
22b
Cl
21b
Scheme 3.

T. Satoh et al. / Tetrahedron 67 (2011) 1102e1113
1105
R3
Finally, we attempted to synthesize 1,2-disubstituted cyclo-
pentenes based on the procedure described above and the result is
shown in Scheme 4. Thus, treatment of vinyl sulfoxide 8 with
lithium enolate of tert-butyl acetate at ꢀ78 ꢁC afforded adduct,
t
R1
COO Bu
t
LiCH(R3)COO Bu
R1
R2
Cl
S
R
R
THF, -78 °C
Lit. 17
R2
S
R
Tol
Tol
S
lithium a-sulfinyl carbanion 23. Addition of excess iodomethane to
a solution of this anion gave methylated compound 24 in quanti-
tative yield.16 In expectation of 1,2-disubstituted cyclopentene 26,
methylated compound 24 was treated with excess i-PrMgCl in
toluene. Quite interestingly only olefin 27, which was produced by
1,2-CH insertion reaction between the methyl hydrogen and the
carbon of the generated magnesium carbenoid 25, was obtained as
a single isolable product. From this result, we recognized that 1,2-
CC insertion and 1,2-CH insertion of magnesium carbenoid, such as
25 are on the delicate balance of the structure and we could hardly
deduce the results at present.
Cl
O
O
28
29
CH2CH2Ph
t
t
Ph(CH2)3COO Bu
Cl
S
COO Bu
EtO
EtO
EtO
EtO
LDA
THF, -78 °C,
15 min, 99%
S
Tol
Tol
Cl
O
O
(R)-8
30 (99% ee)
CH2CH2Ph
EtO
EtO
i-PrMgCl (5 eq)
t
t
t
COO Bu
Cl
COO Bu
LiCH2COO Bu
EtO
EtO
Toluene, -78 ~ 0 °C
90%
THF, -78 °C,
15 min
S(O)Tol
Cl Li
S(O)Tol
31 (89% ee)
8
23
t
COO Bu
i-PrMgCl (10 eq)
CH3I
31
Entry
1
i-PrMgCl (eq)
S(O)Tol
Cl CH3
Yield / %a
47 (67)
-78 ~ 0 °C
99%
Toluene, -78 ~ 0 °C
ee / %
97
24
(3)b
t
1,2-CC insertion
COO Bu
EtO
(5)c
(4)c
(3)c
78
95
96
99
t
2
3
4
COO Bu
EtO
MgCl
Cl CH3
71 (74)
51 (71)
CH3
25
26
1,2-CH
insertion
t
COO Bu
EtO
EtO
a The yield in parenthesis refers to the yield calculated from
the consumed starting material. b Sulfoxide 30 was added to
a solution of i-PrMgCl. c A solution of i-PrMgCl was added
to a solution of 30 in toluene.
CH2
43%
27
Scheme 4.
Scheme 5.
2.2. Asymmetric synthesis of cyclopentenes bearing a tert-
butyl carboxylate moiety at the 1-position starting from
optically pure (R)-chloromethyl p-tolyl sulfoxide
Scheme 5. Thus, when the treatment was conducted with 3 equiv of
i-PrMgCl, the ee was improved to 97%; however, the chemical yield
of 31 was only 47% (entry 1). When 5 equiv of i-PrMgCl was added
to a solution of 30, olefin 31 was obtained in 78% with 95% ee (entry
2). In cases of using lower amount of i-PrMgCl, especially 3 equiv,
the ee was improved to 99% and the chemical yield was 51%. In this
case, significant amount of 30 was recovered without losing the
optical purity and the chemical yield calculated based on the con-
sumed starting material was found to be 71% (entry 4).
Two other examples for the asymmetric synthesis of 1-
substituted cyclopentenes are shown in Scheme 6. The addition
reaction of vinyl sulfoxide (R)-13 with lithium enolate of tert-butyl
4-phenylbutyrate and tert-butyl (4-methylphenyl)acetate gave
adduct 32 and 34, respectively, in quantitative yields with high ee.
The adduct 32 was treated with i-PrMgCl under the same condi-
tions as described above to give the desired 33 in 82% yield with
98% ee. Compared to this, the sulfoxideemagnesium exchange re-
action of 34 required 5 equiv of i-PrMgCl and, as a result, the
enantiopurity of 35 was decreased to 88% ee.
Previously, we reported quite interesting 1,4-asymmetric in-
duction reaction from the sulfoxide stereogenic center. Thus, as
shown in Scheme 5, addition reaction of (R)-vinyl sulfoxides 28
with lithium enolate of tert-butyl carboxylates resulted in the for-
mation of adducts 29 bearing a substituent R3 at the
a-carbon of the
ester group as a single product with perfect 1,4-asymmetric in-
duction from the sulfur stereogenic center. The absolute stereo-
chemistry of the a
-carbon was proved to be R configuration.17
In order to extend the procedure described above to the asym-
metric synthesis of cyclopentenes bearing a tert-butyl carboxylate
moiety at the 1-position, we studied our process starting from opti-
cally pure vinyl sulfoxide (R)-8 (Scheme 5). At first, (R)-8 was syn-
thesized from cyclobutanone 7 with optically pure (R)-chloromethyl
p-tolyl sulfoxide.18 The addition reaction of (R)-8 with lithium enolate
of tert-butyl 4-phenylbutyrate gave adduct 30 in quantitative yield as
a single product. Optical purity of 30 was determined by HPLC with
chiral column (CHIRALCEL OD) and was proved to be over 99%. Finally,
a solution of 30 in toluene was added to a solution of 5 equiv of i-
PrMgCl in toluene to afford 31 in 90% yield. Optical purity, however,
2.3. Synthesis, including asymmetric synthesis, of a-amino
was found to be 89%ee. As the hydrogen on the carbon at the
a
-posi-
acid derivatives bearing a 1-cyclopentene moiety at the
position
a-
tion is present in between the carbonyl and olefinic groups, its acidity
is thought to be increased. Excess i-PrMgCl is presumed to actas a base
to result in a slight racemization.
After some investigations, improvement of the optical purity of
31 was successful and the results are summarized in the table in
When above-mentioned procedure was conducted with glycine
derivative, a synthesis of -amino acid derivatives bearing a 1-
cyclopentene moiety at the -position was realized (Table 3). Thus,
a
a

1106
T. Satoh et al. / Tetrahedron 67 (2011) 1102e1113
CH2CH2Ph
CH2CH2Ph
t
t
Ph(CH2)3COO Bu
i-PrMgCl (3 eq)
Cl
S
COO Bu
t
COO Bu
LDA
Toluene, -78 ~ 0 °C
S
Tol
Tol
THF, -78 °C, 15 min
82% (13% of 32 was
33 (98% ee)
Cl
O
recovered)
O
99%
32 (99% ee)
(R)-13
CH3
CH3
t
t
TolCH2COO Bu
COO Bu
i-PrMgCl (5 eq)
t
COO Bu
LDA
Toluene, -78 ~ 0 °C
S
Tol
THF, -78 °C, 15 min
99%
72% (23% of 34 was
35 (88% ee)
Cl
O
recovered)
34 (99% ee)
Scheme 6.
Table 3
Synthesis of
a
-amino acid derivatives bearing a cyclopentene moiety at the
a
-position
NBn2
COO Bu
NBn2
COO Bu
NBn2
COO Bu
t
R1
R1
R1
t
R1
R1
t
t
R1
R1
Cl
Bn2NCH2COO Bu ( 7.5 eq)
i-PrMgCl (5 eq)
+
R1
S(O)Tol
S(O)Tol
Toluene, -78 ~ 0 °C
LDA / THF, -45 °C, 1 h
Cl
36
8 R1 = CH2OC2H5
38
37
12 R1 = CH2O(CH2)3Ph
13 R1 = H
Entry
1-Chlorovinyl p-tolyl sulfoxide
36
37
38
R1
Yield/%
Yield/%
Yield/%
1
2
3
8
12
13
CH2OC2H5
CH2O(CH2)3Ph
H
36a
36b
36c
88
90
99
37a
37b
37c
56
56
78
38a
38b
24
23
0
the addition reaction of vinyl sulfoxides 8, 12, and 13 with 7.5 equiv
of lithium enolate of N,N-dibenzylglycine tert-butyl ester afforded
adducts 36aec, respectively, in good to quantitative yields.17a At
first, adduct 36a was treated with 5 equiv of i-PrMgCl in toluene.
Somewhat surprisingly, this reaction gave the expected ring-ex-
panded product 37a in 56% yield with bicyclo[2.1.0]pentane de-
rivative 38a (24%) as a byproduct (entry 1). Obviously, 38a was
derived from the 1,3-CH insertion reaction of the derived magne-
sium carbenoid intermediate.9 As shown in entry 2, almost the
same result was obtained from the reaction of 36b with i-PrMgCl.
Quite interestingly, no bicyclo[2.1.0]pentane derivative was
obtained from the reaction of 36c with i-PrMgCl. We still find it
very difficult to propose a rational explanation why bicyclo[2.1.0]
pentane derivatives 38a and 38b were obtained only when adducts
36 have ethereal functional groups on the cyclobutane ring.
Scheme 7 shows the result for the asymmetric synthesis of
NBn2
t
t
Bn2NCH2COO Bu (7. 5 eq)
COO Bu
Cl
S
LDA / THF, -45 °C, 1 h
99%
S
Tol
Tol
Cl
O
O
(R)-13
39 (99% ee)
NBn2
i-PrMgCl (3 eq)
t
COO Bu
Toluene, -78 ~ 0 °C
50% (32% of 39 was
recovered)
40 (85% ee)
Scheme 7.
a
-amino acid derivative 40 starting from (R)-13. Thus, adduct 39
lithium enolate of carboxylic acid N,N-dimethylamides19 gave ad-
ducts 41aed in up to 99% yields. Treatment of 41aed with 5 equiv
of i-PrMgCl in toluene resulted in the formation of cyclopentenes
bearing an amide moiety at the 1-position 42 around 80% yields.
The procedure described above was carried out with sulfones
and the results are summarized in Table 5. The addition reaction of
was derived from (R)-13 with 7.5 equiv of lithium enolate of N,N-
dibenzylglycine tert-butyl ester with 99%ee. Treatment of 39 with
3 equiv of i-PrMgCl was conducted in the same conditions as de-
scribed above (see Scheme 5) to give the desired product 40 in 50%
yield; however, again some racemization was observed.
1-chlorovinyl p-tolyl sulfoxides 8, 12, and 13 with lithium a-sulfo-
2.4. Synthesis of cyclopentenes bearing a carboxylic amide,
an alkylsulfonyl, and acetonitrile moiety at the 1-position
nyl carbanions afforded the expected adducts 43aed in somewhat
lower yields. Treatment of these adducts with 5 equiv of i-PrMgCl
resulted in the formation of the desired cyclopentenes bearing an
alkylsulfonyl moiety at the 1-position 44 in moderate to quantita-
tive yield via the 1,2-CC insertion reaction of the magnesium car-
benoid intermediates.
The procedure described above was carried out with carboxylic
amides and the results are summarized in Table 4. The addition
reaction of 1-chlorovinyl p-tolyl sulfoxides 8, 12, and 13 with

T. Satoh et al. / Tetrahedron 67 (2011) 1102e1113
1107
Table 4
Synthesis of cyclopentenes bearing a carboxylic amide moiety at the 1-position
R2
R2
R1
R2CH2CON(CH3)2
R1
R1
i-PrMgCl (5 eq)
R1
R1
CON(CH3)2
S(O)Tol
CON(CH3)2
Cl
R1
S(O)Tol
LDA / THF, conditions
Toluene, -78 ~ 0 °C
Cl
41
8 R1 = CH2OC2H5
42
12 R1 = CH2O(CH2)3Ph
13 R1 = H
Entry
1-Chlorovinyl p-tolyl sulfoxide
R2CH2CON(CH3)2
Conditions
41
42
R1
R2
(equiv)
Yield/%
Yield/%
1
2
3
4
8
CH2OC2H5
CH2O(CH2)3Ph
H
H
H
H
H
CH3
(5)
(5)
(5)
(10)
ꢀ65 ꢁC, 2 h
41aa
41ba
41cb
41dc
80
84
99
99
42a
42b
42c
42d
76
76
77
81
12
13
13
ꢀ65 ꢁC, 2 h
ꢀ78 ꢁC, 15 min
ꢀ78 ꢁC, 15 min
a
A 4:1 mixture of two diastereomers.
A 15:1 mixture of two diastereomers.
A 2:1 mixture of two diastereomers.
b
c
Table 5
Synthesis of cyclopentenes bearing an alkylsulfonyl moiety at the 1-position
R2
R2
R1
R2CH2SO2Ph
R1
R1
R1
R1
SO2Ph
S(O)Tol
SO2Ph
Cl
i-PrMgCl (5 eq)
Toluene, -78 ~ 0 °C
R1
S(O)Tol
LDA / THF, conditions
Cl
43
8 R1 = CH2OC2H5
44
12 R1 = CH2O(CH2)3Ph
13 R1 = H
Entry
1-Chlorovinyl p-tolyl sulfoxide
R2CH2SO2Ph
Conditions
43
44
R1
R2
(equiv)
Yield/%
Yield/%
1
2
3
4
8
CH2OC2H5
CH2O(CH2)3Ph
H
H
H
H
H
CH3
(5)
(5)
(5)
(10)
ꢀ65 ꢁC, 2 h
43a
43b
43c
44
33
87
60
44a
44b
44c
44d
67
65
78
96
12
13
13
ꢀ65 ꢁC, 2 h
ꢀ78 ꢁC, 15 min
ꢀ78 ꢁC, 15 min
43da
a
A 15:1 mixture of two diastereomers.
Finally, this procedure was carried out with acetonitrile and the
result is shown in Scheme 8. Thus, the treatment of vinyl sulfoxide 8
with lithium carbanion of acetonitrile generated from acetonitrile
with LDA gave adduct 45 as 2:1 mixture of two diastereomers in 88%
yield.20 Treatment of the mixture of 45 with 5 equiv of i-PrMgCl in
toluene resulted in the formation of the expected cyclopentene
bearing acetonitrile moiety at the 1-position 46 in 40% yield. Quite
interestingly, this reaction gave highly strained spirocyclic com-
pound 47 as a byproduct in 27% yield.21
carboxylic acid derivatives and sulfones with magnesium carbenoid
1,2-CC insertion reaction as the key reaction. We believe that the
magnesium carbenoid 1,2-CC insertion reaction presented herein
will be used widely in the one-carbon ring-expansion of cyclo-
butane derivatives to cyclopentenes.
3. Experimental
3.1. General
In conclusion, we have developed a new method for a synthesis,
including asymmetric synthesis, of cyclopentenes bearing a tert-
butyl carboxylate, a carboxylic acid N,N-dimethyl amide, and an
alkylsulfonyl moiety at the 1-position by assemblage of three
components, cyclobutanones, chloromethyl p-tolyl sulfoxide, and
Melting points were measured on a Yanaco MP-S3 apparatus
and are uncorrected. 1H NMR and 13C NMR spectra were measured
in a CDCl3 solution with JEOL JNM-LA 300, 500, BRUKER UltraShield
300, 400, and 600 spectrometer. IR spectra were recorded on
a PerkineElmer spectrum one FT-IR instrument. Electron-impact
mass spectra (MS) were obtained at 70 eV by direct insertion with
JEOL JMS-SX102A. Silica gel 60 N (KANTO CHEMICAL) containing
0.5% fluorescence reagent 254 and a quartz column were used for
column chromatography and the products having UV absorption
were detected by UV irradiation. In experiments requiring a dry
solvent and reagent, THF was distilled from diphenylketyl. Toluene,
dichloromethane, and diisopropylamine were distilled from CaH2.
tert-Butyl acetate, tert-butyl propionate and acetonitrile were dis-
LiCH2CN (5 eq)
Cl
CH2CN
S(O)Tol
EtO
EtO
EtO
EtO
THF, -78 °C, 15 min
88%
S(O)Tol
Cl
8
45
CN
EtO
EtO
i-PrMgCl (5 eq)
CH2CN
EtO
EtO
+
Toluene, -78 ~ 0 °C
47 (27%)
46 (40%)
tilled from anhydrous CaSO4. Compounds 711, 811, 1311, 1822, 44c23
and 44d24 are known.
,
Scheme 8.

1108
T. Satoh et al. / Tetrahedron 67 (2011) 1102e1113
3.1.1. (Rs)-3,3-Bis(ethoxymethyl)-1-[chloro(p-tolylsulfinyl)methyl-
(1H, dd, J¼11.5, 2.7 Hz), 3.27 (1H, d, J¼9.2 Hz), 3.31 (2H, s), 3.36 (1H, d,
J¼9.2 Hz), 3.40 (2H, q, J¼7.0 Hz), 3.42e3.59 (2H, m), 5.55 (1H, s),
7.17e7.35 (7H, m), 7.69 (2H, d, J¼8.2 Hz). MS m/z (%) 576 (Mþ, 0.1), 503
(15), 381 (30), 253 (34), 241 (96), 195 (43), 139 (52), 117 (42), 91 (95),
59 (100). Calcd for C32H45ClO5S: M, 576.2676. Found: m/z 576.2677.
idene]cyclobutane ((R)-8). Colorless oil; [
a]
30 þ162.8 (c 0.49, EtOH)
D
3.1.2. tert-Butyl
{1-[chloro(p-tolylsulfinyl)methyl]-3,3-bis(ethox-
ymethyl)cyclobutyl}acetate (9). tert-Butyl acetate (0.14 mL;
1.0 mmol) was added to a solution of LDA (1.0 mmol) in 3 mL of dry
THF at ꢀ78 ꢁC under argon atmosphere with stirring. After the
solution was stirred for 10 min, a solution of vinyl sulfoxide 8
(71 mg; 0.2 mmol) in THF (1 mL) was added. The reaction mixture
was stirred for 15 min and then reaction was quenched by adding
saturated aq. NH4Cl. The whole mixture was extracted with CHCl3.
The product was purified by silica gel column chromatography to
afford adduct 9 (94 mg; 99%) as colorless oil. IR (neat) 2976, 2932,
2870, 1723 (CO), 1368, 1256, 1154, 1107 (COC), 1055 (SO), 811,
3.1.8. tert-Butyl {1-[chloro(p-tolylsulfinyl)methyl]-3,3-bis(3-phenyl-
propoxymethyl)cyclobutyl}acetate (14c). Colorless oil; IR (neat)
2934, 2860, 1723 (CO), 1496, 1455, 1368, 1153, 1111 (COC), 1055 (SO),
812, 749, 700 cmꢀ1; 1H NMR
d 1.48 (9H, s), 1.76e1.95 (4H, m), 2.34
(3H, s), 2.23e2.37 (3H, m), 2.48e2.76 (5H, m), 2.99 (1H, d, J¼14.8 Hz),
3.08 (1H, d, J¼14.8 Hz), 3.32e3.55 (8H, m), 5.44 (1H, s), 7.04e7.09
(2H, m), 7.14e7.31 (10H, m), 7.70 (2H, d, J¼8.2 Hz). MS m/z (%) 652
(Mþ, 0.2), 579 (4), 457 (13), 285 (11), 137 (27), 119 (55), 91 (100), 57
(18). Calcd for C38H49ClO5S: M, 652.2989. Found: m/z 652.2984.
755 cmꢀ1; 1H NMR
d
1.12 (3H, t, J¼7.1 Hz), 1.19 (3H, t, J¼7.0 Hz), 1.49
(9H, s), 2.20e2.29 (3H, m), 2.42 (3H, s), 2.66 (1H, d, J¼13.8 Hz), 2.96
(1H, d, J¼15.0 Hz), 3.05 (1H, d, J¼15.0 Hz), 3.36e3.41 (4H, m),
3.46e3.50 (4H, m), 5.42 (1H, s), 7.31 (2H, d, J¼8.3 Hz), 7.71 (2H, d,
J¼8.3 Hz). MS m/z (%) 472 (Mþ, 0.7), 399 (34), 277 (59), 241 (15), 195
(47), 185 (27), 149 (32), 137 (100), 91 (28). Calcd for C24H37ClO5S: M,
472.2050. Found: m/z 472.2050.
3.1.9. tert-Butyl 2-{1-[chloro(p-tolylsulfinyl)methyl]-3,3-bis(3-phe-
nylpropoxymethyl)cyclobutyl}propionate (14d). Colorless oil; IR
(neat) 2944, 2861, 1724 (CO), 1496, 1455, 1368, 1152, 1114 (COC),
1054 (SO), 811, 747, 700 cmꢀ1; 1H NMR
d
1.46 (3H, d, J¼7.0 Hz), 1.47
(9H, s), 1.71e1.91 (4H, m), 2.31 (3H, s), 2.27e2.61 (5H, m), 2.62e2.74
(3H, m), 3.18 (1H, q, J¼7.0 Hz), 3.32e3.44 (7H, m), 3.50e3.60 (1H,
m), 5.70 (1H, s), 6.98e7.04 (2H, m), 7.13e7.31 (10H, m), 7.72 (2H, d,
J¼8.2 Hz). MS (FAB) m/z (%) 667 ([MþH]þ, 27), 611 (30), 185 (21),
151 (32), 119 (59), 91 (100), 57 (20). Calcd for C39H52ClO5S: MþH,
667.3224. Found: m/z 667.3228.
3.1.3. tert-Butyl [4,4-bis(ethoxymethyl)cyclopent-1-enyl]acetate (11).
To a flame-dried flask was added dry toluene (0.2 mL) followed by
i-PrMgCl (in ether; 0.39 mmol; 5 equiv) at ꢀ78 ꢁC under argon at-
mosphere. A solution of adduct 9 (37 mg; 0.078 mmol) in toluene
(0.2 mL) was added to the solution of the Grignard reagent dropwise
with stirring and the reaction mixture was slowly allowed to warm
to 0 ꢁC for 2 h. The reaction was quenched by adding saturated aq.
NH4Cl and the whole mixture was extracted with CHCl3. The product
was purified by silica gel column chromatography to afford cyclo-
pentene 11 (17 mg; 73%) as colorless oil. IR (neat) 2977, 2853, 1731
3.1.10. tert-Butyl 2-{1-[chloro(p-tolylsulfinyl)methyl]-3,3-bis(3-phe-
nylpropoxymethyl)cyclobutyl}-4-phenylbutyrate (14e). Colorless oil;
IR (neat) 2944, 2860, 1722 (CO), 1496, 1455, 1367, 1147, 1111 (COC),
1052 (SO), 811, 751, 700 cmꢀ1; 1H NMR
d 1.52 (9H, s), 1.74e1.87 (4H,
m), 2.31 (3H, s), 2.14e2.80 (12H, m), 3.05 (1H, dd, J¼11.3, 2.6 Hz),
3.25e3.44 (7H, m), 3.49e3.59 (1H, m), 5.58 (1H, s), 6.99e7.05 (2H,
m), 7.13e7.33 (15H, m), 7.67 (2H, d, J¼8.2 Hz). MS (FAB) m/z (%) 757
([MþH]þ, 4), 701 (11), 241 (17), 119 (43), 91 (100), 57 (14). Calcd for
C46H58ClO5S: MþH, 757.3693. Found: m/z 757.3691.
(CO), 1369, 1256, 1146, 1111 (COC) cmꢀ1 1H NMR
; d 1.17 (6H, t,
J¼7.0 Hz), 1.44 (9H, s), 2.20 (4H, s), 2.97 (2H, s), 3.33 (4H, s), 3.49 (4H,
q, J¼7.0 Hz), 5.38 (1H, br s). MS m/z (%) 298 (Mþ, 0.9), 242 (15), 196
(16), 183 (12), 152 (10), 150 (55), 137 (48), 105 (43), 91 (55), 57 (100).
Calcd for C17H30O4: M, 298.2144. Found: m/z 298.2148.
3.1.11. tert-Butyl {1-[chloro(p-tolylsulfinyl)methyl]cyclobutyl}acetate
(14f). Colorless oil; IR (neat) 2978, 1724 (CO),1368, 1154, 1083, 1056
3.1.4. 3,3-Bis(3-phenylpropoxymethyl)-1-[chloro(p-tolylsulfinyl)
methylidene]cyclobutane (12). Colorless oil; IR (neat) 2924, 2860,
(SO), 812, 756 cmꢀ1 1H NMR
; d 1.49 (9H, s), 1.90e2.06 (2H, m),
1496, 1454, 1115 (COC), 1088, 1061 (SO), 749, 700 cmꢀ1
;
1H NMR
2.12e2.26 (2H, m), 2.43 (3H, s), 2.38e2.49 (1H, m), 2.55e2.68 (1H,
m), 2.84 (1H, d, J¼15.2 Hz), 3.10 (1H, d, J¼15.2 Hz), 4.92 (1H, s), 7.33
(2H, d, J¼8.0 Hz), 7.71 (2H, d, J¼8.0 Hz). MS (FAB) m/z (%) 357
([MþH]þ, 32), 301 (100), 283 (14), 123 (19). Calcd for C18H26ClO3S:
MþH, 357.1291. Found: m/z 357.1291.
d
1.86e1.96 (4H, m), 2.38 (3H, s), 2.65e2.72 (6H, m), 3.00e3.03 (2H,
m), 3.43e3.50 (8H, m), 7.15e7.22 (6H, m), 7.25e7.32 (6H, m), 7.50
(2H, d, J¼8.2 Hz). MS m/z (%) 536 (Mþ, 8), 235 (11), 119 (28), 91
(100). Calcd for C32H37ClO3S: M, 536.2152. Found: m/z 536.2148.
3.1.5. (Rs)-1-[chloro(p-tolylsulfinyl)methylidene]cyclobutane
((R)-
3.1.12. tert-Butyl 2-{1-[chloro(p-tolylsulfinyl)methyl]cyclobutyl}pro-
pionate (14g). Colorless oil; IR (neat) 2976, 2929, 1724 (CO), 1368,
13). Colorless oil; [
a
]
33 þ192.4 (c 0.53, EtOH).
D
1151, 1084, 1058 (SO), 811 cmꢀ1
;
1H NMR
d
1.36 (3H, d, J¼7.0 Hz),
3.1.6. tert-Butyl 2-{1-[chloro(p-tolylsulfinyl)methyl]-3,3-bis(ethoxy-
methyl)cyclobutyl}propionate (14a). Colorless oil; IR (neat) 2976,
2870, 1725 (CO), 1456, 1368, 1152, 1108 (COC), 1055 (SO), 811,
1.47 (9H, s), 1.76e2.06 (2H, m), 2.44 (3H, s), 2.27e2.50 (4H, m), 3.06
(1H, q, J¼7.0 Hz), 4.74 (1H, s), 7.33 (2H, d, J¼8.2 Hz), 7.71 (2H, d,
J¼8.2 Hz). MS (FAB) m/z (%) 371 ([MþH]þ, 37), 315 (100), 297 (15),
139 (26), 123 (24), 93 (15), 57 (20). Calcd for C19H28ClO3S: MþH,
371.1448. Found: m/z 371.1447.
757 cmꢀ1; 1H NMR
d
1.08 (3H, t, J¼7.0 Hz), 1.15 (3H, t, J¼7.0 Hz), 1.44
(3H, d, J¼7.0 Hz), 1.47 (9H, s), 2.23 (1H, d, J¼13.9 Hz), 2.34 (1H, d,
J¼13.9 Hz), 2.35 (1H, d, J¼13.9 Hz), 2.43 (3H, s), 2.67 (1H, d,
J¼13.9 Hz), 3.15 (1H, q, J¼7.0 Hz), 3.33 (1H, d, J¼9.2 Hz), 3.34 (2H, s),
3.41 (1H, d, J¼9.4 Hz), 3.45 (2H, q, J¼7.0 Hz), 3.45e3.57 (2H, m), 5.67
(1H, s), 7.31 (2H, d, J¼8.1 Hz), 7.75 (2H, d, J¼8.2 Hz). MS m/z (%) 486
(Mþ, 0.1), 413 (19), 291 (29), 209 (36), 151 (100), 140 (52), 57 (54).
Calcd for C25H39ClO5S: M, 486.2207. Found: m/z 486.2210.
3.1.13. tert-Butyl 2-{1-[chloro(p-tolylsulfinyl)methyl]cyclobutyl}-4-
phenylbutyrate (14h). Colorless crystals; mp 110.1e110.5 ꢁC (hex-
ane); IR (KBr) 2971,1713 (CO),1495,1456,1364, 1147,1056 (SO), 812,
699 cmꢀ1; 1H NMR
d 1.52 (9H, s), 1.72e2.08 (3H, m), 2.15e2.33 (3H,
m), 2.43 (3H, s), 2.38e2.50 (2H, m), 2.54e2.80 (2H, m), 2.98 (1H, dd,
J¼11.5, 2.8 Hz), 4.67 (1H, s), 7.18e7.35 (7H, m), 7.66 (2H, d,
J¼8.2 Hz). Anal. Calcd for C26H33ClO3S: C, 67.73; H, 7.21; Cl, 7.69; S,
6.95. Found: C, 67.91; H, 7.18; Cl, 7.71; S, 6.96.
3.1.7. tert-Butyl 2-{1-[chloro(p-tolylsulfinyl)methyl]-3,3-bis(ethoxy-
methyl)cyclobutyl}-4-phenylbutyrate (14b). Colorless oil; IR (neat)
2975, 2868, 1723 (CO), 1455, 1367, 1147, 1107 (COC), 1053 (SO), 812,
753, 700 cmꢀ1; 1H NMR
1.52 (9H, s), 2.12e2.39 (5H, m), 2.42 (3H, s), 2.56e2.80 (3H, m), 3.03
d
1.10 (3H, t, J¼7.0 Hz), 1.11 (3H, t, J¼7.0 Hz),
3.1.14. tert-Butyl {1-[chloro(p-tolylsulfinyl)methyl]cyclobutyl}-p-tol-
ylacetate (14i). Colorless oil; IR (neat) 2978, 1727 (CO), 1513, 1368,

T. Satoh et al. / Tetrahedron 67 (2011) 1102e1113
1109
1142, 1082, 1056 (SO), 811, 752 cmꢀ1
;
1H NMR
d
1.44 (9H, s),
(Mþ, 7), 140 (31), 95 (60), 67 (26), 57 (100). Calcd for C12H20O2: M,
1.39e1.56 (1H, m), 1.78e1.94 (1H, m), 2.36 (3H, s), 2.42 (3H, s),
2.37e2.50 (1H, m), 2.51e2.66 (3H, m), 4.28 (1H, s), 4.69 (1H, s), 7.17
(2H, d, J¼8.0 Hz), 7.30 (2H, d, J¼8.1 Hz), 7.42 (2H, d, J¼8.1 Hz), 7.67
(2H, d, J¼8.2 Hz). MS (FAB) m/z (%) 447 ([MþH]þ, 49), 391 (100), 373
(23), 215 (42), 187 (30), 149 (48), 139 (32), 105 (23), 57 (33). Calcd
for C25H32ClO3S: MþH, 447.1761. Found: m/z 447.1766.
196.1463. Found: m/z 196.1461.
3.1.22. tert-Butyl
Colorless oil; IR (neat) 2977, 2932, 1728 (CO), 1455, 1367, 1143,
699 cmꢀ1; 1H NMR
1.46 (9H, s), 1.79e1.93 (3H, m), 2.03e2.18 (1H,
2-cyclopent-1-enyl-4-phenylbutyrate
(15h).
d
m), 2.24e2.37 (4H, m), 2.50e2.66 (2H, m), 3.08 (1H, t, J¼7.5 Hz),
5.54 (1H, br s), 7.15e7.22 (3H, m), 7.25e7.32 (2H, m). MS m/z (%) 286
(Mþ, 3), 230 (57), 185 (34), 126 (36), 104 (100), 91 (67), 57 (81).
Calcd for C19H26O2: M, 286.1933. Found: m/z 286.1936.
3.1.15. tert-Butyl
pionate (15a). Colorless oil; IR (neat) 2977, 2852, 1732 (CO), 1459,
1368, 1252, 1151, 1112 (COC) cmꢀ1; 1H NMR
2-[4,4-bis(ethoxymethyl)cyclopent-1-enyl]pro-
d
1.17 (6H, t, J¼7.0 Hz),
1.22 (3H, d, J¼7.0 Hz), 1.44 (9H, s), 2.11e2.26 (4H, m), 3.08 (1H, q,
J¼7.0 Hz), 3.32 (4H, s), 3.48 (4H, q, J¼7.0 Hz), 5.36 (1H, br s). MS m/z
(%) 312 (Mþ, 4), 256 (21), 211 (23), 197 (22), 164 (78), 151 (81), 119
(52), 105 (100), 91 (85), 57 (100). Calcd for C18H32O4: M, 312.2301.
Found: m/z 312.2303.
3.1.23. tert-Butyl cyclopent-1-enyl-p-tolylacetate (15i). Colorless
oil; IR (neat) 2929, 1731 (CO), 1514, 1368, 1144 cmꢀ1; 1H NMR
d 1.43
(9H, s), 1.80e1.91 (2H, m), 2.21e2.28 (2H, m), 2.33 (3H, s),
2.29e2.38 (2H, m), 4.22 (1H, s), 5.48e5.52 (1H, m), 7.11 (2H, d,
J¼8.1 Hz), 7.18 (2H, d, J¼8.1 Hz). MS m/z (%) 272 (Mþ, 3), 216 (16),
171 (100), 143 (23), 129 (12), 105 (16), 57 (32). Calcd for C18H24O2:
M, 272.1776. Found: m/z 272.1775.
3.1.16. tert-Butyl 2-[4,4-bis(ethoxymethyl)cyclopent-1-enyl]-4-phe-
nylbutyrate (15b). Colorless oil; IR (neat) 2976, 2852, 1728 (CO),
1455, 1368, 1256, 1143, 1112 (COC), 700 cmꢀ1; 1H NMR
d
1.17 (6H, t,
3.1.24. 1-{2-{1-[Chloro(p-tolylsulfinyl)methyl]-3,3-bis(ethoxymethyl)
cyclobutyl}ethoxymethyl}-p-methoxybenzene (16). DIBAL-H (in
hexane; 12.5 mmol) was added to a solution of adduct 9 (1.19g;
2.5 mmol) in dry toluene (25 mL) at 0 ꢁC with stirring under argon
atmosphere. The reaction mixture was stirred for 10 min and the
reaction was quenched by 4% HCl at 0 ꢁC. The whole was extracted
with CHCl3. The product was purified by flash column chroma-
tography to afford an alcohol (0.91 g; 90%) as colorless oil.
J¼7.0 Hz), 1.45 (9H, s), 1.78e1.91 (1H, m), 2.00e2.13 (1H, m), 2.22
(4H, s), 2.57 (2H, t, J¼7.9 Hz), 3.02 (1H, t, J¼7.5 Hz), 3.31 (2H, s), 3.32
(2H, s), 3.47 (2H, q, J¼7.0 Hz), 3.48 (2H, q, J¼7.0 Hz), 5.41 (1H, br s),
7.14e7.21 (3H, m), 7.24e7.31 (2H, m). MS m/z (%) 402 (Mþ, 1), 241
(58), 195 (36), 150 (80),136 (62),117 (72), 105 (40), 91 (100), 57 (52).
Calcd for C25H38O4: M, 402.2770. Found: m/z 402.2762.
3.1.17. tert-Butyl [4,4-bis(3-phenylpropoxymethyl)cyclopent-1-enyl]
A solution of the alcohol (0.2 g; 0.5 mmol) in EtOAc (2.5 mL) was
added Ag2O (0.35 g; 1.5 mmol) and p-methoxybenzyl chloride
(0.2 mL; 1.5 mmol). The reaction mixture was refluxed for 12 h. The
reaction mixture was filtered and the solvent was evaporated under
reduced pressure. The residue was purified by flash column chro-
matography to afford 16 (98 mg; 37%) as colorless oil. IR (neat)
2974, 2932, 2866,1770,1738,1614,1514,1248,1174,1107(COC),1054
acetate (15c). Colorless oil; IR (neat) 2930, 2854, 1732 (CO), 1497,
1455, 1367, 1255, 1145, 1115 (COC), 746, 700 cmꢀ1 1H NMR
; d 1.44
(9H, s), 1.82e1.93 (4H, m), 2.22 (4H, s), 2.67 (4H, t, J¼7.7 Hz), 2.98
(2H, br s), 3.35 (4H, s), 3.43 (4H, t, J¼6.4 Hz), 5.40 (1H, br s),
7.14e7.20 (6H, m), 7.23e7.30 (4H, m). MS m/z (%) 478 (Mþ, 0.2), 422
(3), 286 (17), 150 (40), 118 (58), 91 (100), 57 (27). Calcd for
C31H42O4: M, 478.3083. Found: m/z 478.3086.
(SO), 912, 811, 733 cmꢀ1; 1H NMR
d
1.11 (3H, t, J¼7.0 Hz), 1.16 (3H, t,
J¼7.0 Hz), 2.02 (1H, d, J¼14.1 Hz), 2.08 (1H, d, J¼14.1 Hz), 2.17 (1H, d,
J¼13.0 Hz), 2.24e2.40 (2H, m), 2.43 (3H, s), 2.67 (1H, d, J¼13.2 Hz),
3.29 (2H, s), 3.32 (2H, d, J¼4.0 Hz), 3.43 (2H, q, J¼7.0 Hz), 3.45e3.54
(2H, m), 3.71e3.86 (2H, m), 3.81 (3H, s), 4.50 (2H, s), 5.31 (1H, s),
5.89 (2H, d, J¼8.5 Hz), 7.30 (4H, d, J¼8.5 Hz), 7.71 (2H, d, J¼8.0 Hz).
MS m/z (%) 522 (Mþ, trace), 505 (trace), 121 (100). Calcd for
C28H39ClO5S: M, 522.2207. Found: m/z 522.2203.
3.1.18. tert-Butyl
enyl]propionate (15d). Colorless oil; IR (neat) 2934, 2853,1729 (CO),
1497, 1455, 1367, 1252, 1150, 1114 (COC), 746, 699 cmꢀ1 1H NMR
2-[4,4-bis(3-phenylpropoxymethyl)cyclopent-1-
;
d
1.23 (3H, d, J¼7.1 Hz), 1.43 (9H, s), 1.82e1.95 (4H, m), 2.21 (4H, br
s), 2.67 (4H, t, J¼7.6 Hz), 3.09 (1H, q, J¼7.0 Hz), 3.34 (4H, s), 3.43 (4H,
t, J¼6.3 Hz), 5.37 (1H, br s), 7.14e7.21 (6H, m), 7.23e7.31 (4H, m). MS
m/z (%) 492 (Mþ, 0.6), 436 (4), 391 (4), 300 (22), 164 (44), 151 (17),
118 (69), 91 (100), 57 (26). Calcd for C32H44O4: M, 492.3240. Found:
m/z 492.3242.
3.1.25. 1-{2-[4,4-Bis(ethoxymethyl)cyclopent-1-enyl]ethoxy}-p-me-
thoxybenzene (17). Colorless oil; IR (neat) 2973, 2930, 2851, 1613,
1513, 1464,1442, 1374, 1355,1248, 1172,1106 (COC),1037, 819 cmꢀ1
;
3.1.19. tert-Butyl
enyl]-4-phenylbutyrate (15e). Colorless oil; IR (neat) 2931, 2855, 1727
(CO), 1496, 1455, 1367, 1256, 1142, 1114 (COC), 746, 699 cmꢀ1 1H
NMR 1.45 (9H, s),1.81e1.92 (5H, m), 2.00e2.15 (1H, m), 2.22 (4H, br
2-[4,4-bis(3-phenylpropoxymethyl)cyclopent-1-
1H NMR
d
1.17 (6H, t, J¼7.0 Hz), 2.13 (2H, br s), 2.15e2.19 (2H, m),
2.33 (2H, t, J¼6.8 Hz), 3.32 (4H, s), 3.49 (4H, q, J¼7.0 Hz), 3.53 (2H, t,
J¼7.0 Hz), 3.80 (3H, s), 4.44 (2H, s), 5.25 (1H, br s), 6.87 (2H, d,
J¼8.6 Hz), 7.26 (2H, d, J¼8.6 Hz). MS m/z (%) 348 (Mþ, 8), 121 (100),
105 (12). Calcd for C21H32O4: M, 348.2301. Found: m/z 348.2301.
;
d
s), 2.58 (2H, t, J¼7.8 Hz), 2.67 (4H, t, J¼7.6 Hz), 3.03 (1H, t, J¼7.5 Hz),
3.33 (2H, s), 3.34 (2H, s), 3.42 (2H, t, J¼6.3 Hz), 3.43 (2H, t, J¼6.3 Hz),
5.42 (1H, br s), 7.13e7.31 (15H, m). MS m/z (%) 582 (Mþ, 0.6), 390
(23), 254 (25), 241 (28),150 (55),136 (24),118 (55),105 (19), 91 (100),
57 (22). Calcd for C39H50O4: M, 582.3709. Found: m/z 582.3716.
3.1.26. (E)-2-phenethyl-1-[chloro(p-tolylsulfinyl)methylidene]cyclo-
butane (19a). Colorless oil; IR (neat) 3025, 2922, 2856, 1493, 1454,
1087, 1059 (SO), 886, 808, 750, 700 cmꢀ1; 1H NMR
d 1.80e1.89 (1H,
m), 1.97e2.06 (1H, m), 2.23e2.34 (2H, m), 2.40 (3H, s), 2.60e2.68
(1H, m), 2.72e2.78 (1H, m), 2.78e2.86 (2H, m), 3.42e3.52 (1H, m),
7.18e7.23 (3H, m), 7.29e7.32 (4H, m), 7.49 (2H, d, J¼8.2 Hz). MS m/z
(%) 344 (Mþ, 7), 327 (22), 253 (14), 240 (23), 223 (56), 204 (13), 169
(15), 140 (40), 105 (16), 91 (100). Calcd for C20H21ClOS: M, 344.1002.
Found: m/z 344.1001.
3.1.20. tert-Butyl cyclopent-1-enylacetate (15f). Colorless oil; IR
(neat) 2978, 2849, 1735 (CO), 1368, 1254, 1149 cmꢀ1; 1H NMR
d 1.45
(9H, s), 1.89 (2H, q, J¼7.5 Hz), 2.28e2.37 (4H, m), 3.02 (2H, s), 5.52
(1H, br s). MS m/z (%) 182 (Mþ, 1), 126 (15), 109 (10), 81 (30), 57
(100), 41 (32). Calcd for C11H18O2: M, 182.1307. Found: m/z 182.1311.
3.1.21. tert-Butyl 2-cyclopent-1-enylpropionate (15g). Colorless oil;
3.1.27. (Z)-2-phenethyl-1-[chloro(p-tolylsulfinyl)methylidene]cyclo-
butane (19b). Colorless oil; IR (neat) 2951, 2927, 1492, 1454, 1085,
IR (neat) 2978, 2929, 1732 (CO), 1368, 1255, 1151 cmꢀ1 1H NMR
;
d
1.24 (3H, d, J¼7.1 Hz), 1.44 (9H, s), 1.86 (2H, q, J¼7.5 Hz), 2.27e2.34
1056 (SO), 888, 808, 752, 702 cmꢀ1
;
1H NMR
d
1.83e1.95 (2H, m),
(4H, m), 3.13 (1H, q, J¼7.0 Hz), 5.48e5.52 (1H, m). MS m/z (%) 196
2.21e2.33 (2H, m), 2.40 (3H, s), 2.52e2.63 (1H, m), 2.67e2.76 (1H,

1110
T. Satoh et al. / Tetrahedron 67 (2011) 1102e1113
m), 2.94e3.04 (1H, m), 3.08e3.27 (2H, m), 7.14e7.20 (3H, m),
7.24e7.33 (4H, m), 7.49 (2H, d, J¼8.2 Hz). MS m/z (%) 344 (Mþ, 43),
327 (12), 237 (13), 223 (12), 169 (14), 140 (35), 91 (100). Calcd for
C20H21ClOS: M, 344.1002. Found: m/z 344.1001.
3.53e3.57 (1H, m), 7.30 (2H, d, J¼8.3 Hz), 7.60 (2H, d, J¼8.3 Hz). MS
(FAB) m/z (%) 487 ([MþH]þ, 18), 431 (19), 291 (15), 255 (14), 211
(30), 151 (100), 119 (13), 105 (14), 57 (13). Calcd for C25H40ClO5S:
MþH, 487.2285. Found: m/z 487.2287.
3.1.28. tert-Butyl {1-[chloro(p-tolylsulfinyl)methyl]-2-phenethylcy-
clobutyl}acetate (20a). Colorless oil; IR (neat) 2977, 1723 (CO),1495,
3.1.33. tert-Butyl [1-ethenyl-3,3-bis(ethoxymethyl)cyclobutyl]acetate
(27). Colorless oil; IR (neat) 2976, 2932, 2866,1731 (CO),1368,1155,
1455, 1368, 1154, 1083, 1057 (SO), 812, 750, 699 cmꢀ1
;
1H NMR
1111 (COC) cmꢀ1
;
1H NMR
d
1.16 (3H, t, J¼7.0 Hz), 1.20 (3H, t,
d
1.49 (9H, s), 1.64e1.77 (2H, m), 2.05e2.22 (2H, m), 2.42 (3H, s),
J¼7.0 Hz), 1.40 (9H, s), 1.96 (2H, d, J¼12.5 Hz), 2.02 (2H, d,
J¼12.5 Hz), 2.49 (2H, s), 3.36 (2H, s), 3.36 (2H, s), 3.46 (2H, q,
J¼7.0 Hz), 3.51 (2H, q, J¼7.0 Hz), 5.04 (1H, dd, J¼10.3, 1.1 Hz), 5.05
(1H, dd, J¼17.5,1.1 Hz), 6.02 (1H, dd, J¼17.5, 10.3 Hz). MS m/z (%) 312
(Mþ, 0.5), 210 (38), 164 (96), 151 (73), 119 (54), 112 (52), 105 (100),
91 (33), 85 (54), 57 (90). Calcd for C18H32O4: M, 312.2301. Found:
m/z 312.2306.
2.36e2.48 (2H, m), 2.55e2.68 (2H, m), 2.72e2.80 (1H, m), 2.82 (1H,
d, J¼13.8 Hz), 2.92 (1H, d, J¼13.8 Hz), 4.72 (1H, s), 7.12e7.18 (3H, m),
7.22e7.27 (2H, m), 7.31 (2H, d, J¼8.0 Hz), 7.68 (2H, d, J¼8.2 Hz). MS
(FAB) m/z (%) 461 ([MþH]þ, 35), 405 (100), 169 (70), 140 (25), 91
(44), 57 (24). Calcd for C26H34ClO3S: MþH, 461.1917. Found: m/z
461.1916.
30
3.1.29. tert-Butyl {1-[chloro(p-tolylsulfinyl)methyl]-2-phenethylcy-
clobutyl}acetate (20b). Colorless oil; IR (neat) 2977, 2933, 1728
(CO),1495,1455,1368,1156,1083,1055 (SO), 812, 753, 699 cmꢀ1; 1H
3.1.34. Compound (30). Colorless oil; [
a
]
ꢀ81.0 (c 0.52, EtOH).
D
3.1.35. Compound (31). Adduct 30 (58 mg; 0.1 mmol) in toluene
(5 mL) was added to a flame-dried flask at ꢀ78 ꢁC under argon
atmosphere with stirring. i-PrMgCl (in ether; 0.3 mmol; 3 equiv)
was added dropwise with stirring and the reaction mixture was
slowly allowed to warm to 0 ꢁC for 2 h. The reaction was quenched
by adding saturated aq. NH4Cl and the whole mixture was extracted
with CHCl3. The product was purified by silica gel column chro-
matography to afford cyclopentene 31 (21 mg; 51%, 99%ee) and
NMR
d 1.43 (9H, s), 1.57e1.73 (2H, m), 1.95e2.15 (3H, m), 2.42 (3H,
s), 2.45e2.65 (3H, m), 2.83 (1H, d, J¼16.0 Hz), 2.80e2.92 (1H, m),
2.99 (1H, d, J¼16.0 Hz), 5.11 (1H, s), 7.14e7.21 (3H, m), 7.24e7.33
(4H, m), 7.68 (2H, d, J¼8.2 Hz). MS m/z (%) 460 (Mþ, trace), 229 (22),
169 (74), 140 (100), 91 (54), 57 (34). Calcd for C26H33ClO3S: M,
460.1839. Found: m/z 460.1836.
3.1.30. tert-Butyl
Colorless oil; IR (neat) 2928, 1731 (CO), 1455, 1368, 1256, 1148,
699 cmꢀ1 1H NMR
1.42 (9H, s), 1.38e1.47 (1H, m), 1.58e1.63
(5-phenethylcyclopent-1-enyl)acetate
(22a).
starting material 30 (16 mg; 28%). Colorless oil; [
a
]
D
29 ꢀ16.7 (c 0.53,
EtOH).
;
d
(1H, m), 1.91e1.97 (1H, m), 2.14e2.19 (1H, m), 2.27e2.33 (2H, m),
2.51e2.56 (1H, m), 2.66e2.70 (2H, m), 2.93 (1H, d, J¼15.6 Hz),
3.03 (1H, d, J¼15.6 Hz), 5.56 (1H, br s), 7.14e7.19 (3H, m),
3.1.36. Compound (32). Colorless crystals; [
a
]
D
30 ꢀ65.8 (c 0.48, EtOH).
29
D
3.1.37. Compound (33). Colorless oil; [
3.1.38. Compound (34). Colorless oil; [
3.1.39. Compound (35). Colorless oil; [
a
]
ꢀ17.2 (c 0.53, EtOH).
ꢀ69.5 (c 0.52, EtOH).
7.26e7.29 (2H, m). 13C NMR
d 28.0, 29.9, 31.0, 33.8, 35.3, 36.5,
32
46.4, 80.5, 125.7, 128.0, 128.3, 128.4, 140.0, 142.7, 170.9. MS m/z (%)
286 (Mþ, 1.0), 230 (96), 213 (13), 185 (14), 169 (87), 139 (25), 104
(55), 91 (91), 79 (32), 57 (100). Calcd for C19H26O2: M, 286.1933.
Found: m/z 286.1930.
a
a
]
D
]
D
31 þ0.7 (c 0.27, EtOH).
3.1.40. tert-Butyl {1-[chloro(p-tolylsulfinyl)methyl]-3,3-bis(ethoxy-
methyl)cyclobutyl}-N,N-dibenzylaminoacetate (36a). Colorless oil;
IR (neat) 2976, 2868, 1722 (CO), 1495, 1455, 1369, 1152, 1108 (COC),
3.1.31. tert-Butyl
Colorless oil; IR (neat) 2929, 1732 (CO), 1455, 1368, 1254, 1149,
699 cmꢀ1; 1H NMR
1.45 (9H, s), 1.42e1.55 (1H, m), 1.55e1.75 (2H,
(3-phenethylcyclopent-1-enyl)acetate
(22b).
d
1051 (SO), 755, 699 cmꢀ1; 1H NMR
d
1.05 (3H, t, J¼7.0 Hz),1.11 (3H, t,
m), 2.10e2.16 (1H, m), 2.23e2.38 (2H, m), 2.62 (2H, t, J¼8.0 Hz),
J¼7.0 Hz), 1.64 (9H, s), 1.90 (1H, d, J¼13.8 Hz), 2.08 (1H, d,
J¼13.8 Hz), 2.42 (3H, s), 3.01 (1H, d, J¼13.6 Hz), 3.12 (1H, d,
J¼13.6 Hz), 3.24e3.61 (10H, m), 3.92 (1H, s), 4.33 (2H, d, J¼13.3 Hz),
5.63 (1H, s), 7.18e7.36 (8H, m), 7.55 (4H, d, J¼7.4 Hz), 7.69 (2H, d,
J¼8.0 Hz). MS (FAB) m/z (%) 668 ([MþH]þ, 28), 576 (24), 426 (15),
392 (17), 254 (40), 196 (18), 91 (100). Calcd for C38H51ClNO5S: MþH,
668.3176. Found: m/z 668.3176.
2.64e2.70 (1H, m), 3.01 (2H, s), 5.50 (1H, br s), 7.15e7.19 (3H, m),
7.25e7.29 (2H, m). 13C NMR
d 28.0, 30.4, 34.2, 34.6, 37.8, 38.5, 45.1,
80.5,125.6,128.3,128.4,131.8,137.2,142.7,170.8. MS m/z (%) 286 (Mþ,
1), 230 (47), 185 (15), 170 (38), 125 (23), 104 (17), 91 (77), 79 (25), 57
(100). Calcd for C19H26O2: M, 286.1932. Found: m/z 286.1931.
3.1.32. tert-Butyl {1-[1-chloro-1-(p-tolylsulfinyl)ethyl]-3,3-bis(ethoxy-
methyl)cyclobutyl}acetate (24). tert-Butyl acetate (0.51 mL;
3.8 mmol) was added to a solution of LDA (3.8 mmol) in 13 mL of
dry THF at ꢀ78 ꢁC under argon atmosphere with stirring. After the
solution was stirred for 10 min, a solution of vinyl sulfoxide 8
(268 mg; 0.75 mmol) in THF (2 mL) was added. The reaction mix-
ture was stirred for 15 min and CH3I (0.47 mL, 7.5 mmol) was added.
The reaction mixture was slowly allowed to warm to 0 ꢁC for 2 h.
The reaction was quenched by adding saturated aq. NH4Cl and the
whole mixture was extracted with CHCl3. The product was purified
by silica gel column chromatography to afford adduct 24 (365 mg;
99%) as a 5:1 mixture of two diastereomers. Main product: colorless
oil; IR (neat) 2976, 2933, 2869, 1728 (CO), 1369, 1251, 1153, 1108
3.1.41. tert-Butyl {1-[chloro(p-tolylsulfinyl)methyl]-3,3-bis(3-phenyl-
propoxymethyl)cyclobutyl}-N,N-dibenzylaminoacetate
(36b). Colorless oil; IR (neat) 2946, 2860, 1722 (CO), 1496, 1455,
1368, 1218, 1151, 1111 (COC), 1049 (SO), 756, 699 cmꢀ1 1H NMR
;
d
1.63 (9H, s), 1.68e1.86 (4H, m), 1.91 (1H, d, J¼13.9 Hz), 2.14 (1H, d,
J¼13.9 Hz), 2.31 (3H, s), 2.39e2.51 (2H, m), 2.56e2.68 (2H, m), 3.04
(1H, d, J¼13.7 Hz), 3.16 (1H, d, J¼13.7 Hz), 3.28e3.38 (6H, m), 3.46
(1H, d, J¼9.0 Hz), 3.49e3.59 (3H, m), 3.94 (1H, s), 4.33 (2H, d,
J¼12.9 Hz), 5.66 (1H, s), 6.99 (2H, d, J¼7.3 Hz), 7.11e7.34 (16H, m),
7.55 (4H, d, J¼7.5 Hz), 7.67 (2H, d, J¼7.9 Hz). MS (FAB) m/z (%) 848
([MþH]þ, 10), 756 (7), 254 (28), 196 (12), 91 (100). Calcd for
C52H63ClNO5S: MþH, 848.4115. Found: m/z 848.4121.
(COC), 1066 (SO), 813, 755 cmꢀ1
;
1H NMR
d
1.15 (3H, t, J¼7.0 Hz),
1.21 (3H, t, J¼7.0 Hz),1.36 (3H, s),1.49 (9H, s), 2.12 (1H, d, J¼13.7 Hz),
2.29 (1H, d, J¼13.1 Hz), 2.37 (1H, d, J¼13.1 Hz), 2.42 (3H, s), 2.67 (1H,
d, J¼13.7 Hz), 3.19 (1H, d, J¼15.3 Hz), 3.27 (1H, d, J¼15.3 Hz),
3.40e3.45 (3H, m), 3.45 (2H, q, J¼7.0 Hz), 3.54 (2H, q, J¼7.0 Hz),
3.1.42. tert-Butyl {1-[chloro(p-tolylsulfinyl)methyl]cyclobutyl}-N,N-
dibenzylaminoacetate (36c). Colorless oil; IR (neat) 2977, 1723 (CO),
1495, 1455, 1368, 1148, 1082, 1054 (SO), 750, 699 cmꢀ1 1H NMR
;
d
1.64 (9H, s), 1.65e1.94 (4H, m), 2.39 (3H, s), 2.40e2.52 (1H, m),

T. Satoh et al. / Tetrahedron 67 (2011) 1102e1113
1111
2.89e3.02 (1H, m), 3.71 (2H, d, J¼13.8 Hz), 3.79 (1H, s), 4.05 (2H, d,
J¼13.8 Hz), 5.13 (1H, s), 7.14e7.40 (10H, m), 7.47 (4H, d, J¼7.1 Hz).
MS (FAB) m/z (%) 552 ([MþH]þ, 27), 460 (12), 450 (13), 310 (17), 276
(22), 254 (32), 196 (12), 91 (100). Calcd for C32H39ClNO3S: MþH,
552.2339. Found: m/z 552.2340.
(0.8H, d, J¼13.6 Hz), 2.20 (0.2H, d, J¼13.3 Hz), 2.22 (0.8H, d,
J¼13.1 Hz), 2.33 (0.8H, d, J¼13.1 Hz), 2.41 (0.6H, s), 2.42 (2.4H, s),
2.38e2.42 (0.2H, m), 2.50 (0.2H, d, J¼13.3 Hz), 2.62 (0.8H, d,
J¼13.6 Hz), 2.97 (0.6H, s), 2.99 (2.4H, s), 3.07 (0.6H, s), 3.09 (0.8H, d,
J¼15.2 Hz), 3.10 (2.4H, s), 3.06e3.12 (0.2H, m), 3.20 (0.2H, d,
J¼16.2 Hz), 3.31 (0.8H, d, J¼15.2 Hz), 3.34e3.56 (8.0H, m), 5.50
(0.2H, s), 5.61 (0.8H, s), 7.30 (2.0H, d, J¼8.2 Hz), 7.49 (0.4H, d,
J¼8.3 Hz), 7.70 (1.6H, d, J¼8.3 Hz). MS m/z (%) 443 (Mþ, 0.2), 304
(40), 256 (18), 220 (20), 176 (33), 164 (44), 72 (100). Calcd for
C22H34ClNO4S: M, 443.1897. Found: m/z 443.1900.
3.1.43. tert-Butyl [4,4-bis(ethoxymethyl)cyclopent-1-enyl]-N,N-di-
benzylaminoacetate (37a). Colorless oil; IR (neat) 2976, 2851, 1729
(CO), 1495, 1455, 1368, 1113 (COC), 756, 698 cmꢀ1 1H NMR
; d 1.07
(3H, t, J¼7.0 Hz), 1.16 (3H, t, J¼7.0 Hz), 1.52 (9H, s), 2.06e2.30 (3H,
m), 2.61 (1H, d, J¼16.8 Hz), 3.19e3.39 (6H, m), 3.47 (2H, q, J¼7.0 Hz),
3.63 (2H, d, J¼14.2 Hz), 3.83 (1H, br s), 3.96 (2H, d, J¼14.2 Hz), 5.52
(1H, br s), 7.18e7.34 (6H, m), 7.38 (4H, d, J¼7.1 Hz). MS m/z (%) 493
(Mþ, 0.1), 392 (100), 91 (33). Calcd for C31H43NO4: M, 493.3192.
Found: m/z 493.3186.
3.1.51. {1-[Chloro(p-tolylsulfinyl)methyl]-3,3-bis(3-phenyl-
propoxymethyl)cyclobutyl}-N,N-dimethylacetamide (41b). Colorless
oil (about 4:1 mixture of two diastereomers); IR (neat) 2941, 2860,
1645 (CO), 1496, 1455, 1397, 1111 (COC), 1053 (SO), 750, 700 cmꢀ1
;
1H NMR
d
1.74e1.97 (4.0H, m), 2.12 (0.2H, d, J¼13.4 Hz), 2.20 (0.8H,
3.1.44. tert-Butyl
enyl]-N,N-dibenzylaminoacetate (37b). Colorless oil; IR (neat) 2930,
2852, 1729 (CO), 1496, 1455, 1367, 1120 (COC), 745, 698 cmꢀ1 1H
NMR
[4,4-bis(3-phenylpropoxymethyl)cyclopent-1-
d, J¼13.5 Hz), 2.27 (1.0H, d, J¼13.3 Hz), 2.34 (2.4H, s), 2.36 (0.6H, s),
2.36 (0.8H, d, J¼13.5 Hz), 2.44 (0.2H, d, J¼13.3 Hz), 2.48e2.74 (5.0H,
m), 2.94 (0.6H, s), 2.96 (2.4H, s), 3.02 (0.6H, s), 3.04 (0.8H, d,
J¼15.0 Hz), 3.08 (2.4H, s), 3.08 (0.2H, d, J¼15.2 Hz), 3.17 (0.2H, d,
J¼15.2 Hz), 3.30 (0.8H, d, J¼15.0 Hz), 3.34e3.53 (8.0H, m), 5.47
(0.2H, s), 5.60 (0.8H, s), 7.04e7.12 (2.0H, m), 7.14e7.31 (10.0H, m),
7.48 (0.4H, d, J¼8.3 Hz), 7.68 (1.6H, d, J¼8.3 Hz). MS (FAB) m/z (%)
624 ([MþH]þ, 48), 484 (27), 164 (26), 119 (25), 91 (100), 72 (49).
Calcd for C36H47ClNO4S: MþH, 624.2914. Found: m/z 624.2913.
;
d
1.52 (9H, s), 1.71e1.92 (4H, m), 2.11 (1H, d, J¼16.5 Hz), 2.30
(2H, br s), 2.54e2.69 (5H, m), 3.22e3.37 (6H, m), 3.41 (2H, t,
J¼6.4 Hz), 3.64 (2H, d, J¼14.2 Hz), 3.84 (1H, br s), 3.96 (2H, d,
J¼14.2 Hz), 5.53 (1H, br s), 7.09e7.32 (16H, m), 7.39 (4H, d,
J¼7.0 Hz). MS m/z (%) 673 (Mþ, 0.2), 572 (100), 91 (30). Calcd for
C45H55NO4: M, 673.4131. Found: m/z 673.4127.
3.1.45. tert-Butyl
(37c). Colorless oil; IR (neat) 2976, 2931, 2848, 1729 (CO), 1494,
1455, 1367, 1251, 1131, 745, 698 cmꢀ1 1H NMR
1.53 (9H, s), 1.83
(cyclopent-1-enyl)-N,N-dibenzylaminoacetate
3.1.52. {1-[Chloro(p-tolylsulfinyl)methyl]cyclobutyl}-N,N-dimethyl-
acetamide (41c). Main product: colorless oil; IR (neat) 2946, 1797,
;
d
1644 (CO), 1494, 1400, 1085, 1054 (SO) cmꢀ1 1H NMR
; d 1.92e2.04
(2H, q, J¼7.5 Hz), 2.14e2.29 (1H, m), 2.29e3.38 (2H, m), 2.54e2.68
(1H, m), 3.65 (2H, d, J¼14.3 Hz), 3.89 (1H, br s), 3.96 (2H, d,
J¼14.3 Hz), 5.63e5.68 (1H, m), 7.19e7.28 (2H, m), 7.29e7.34 (4H,
m), 7.36e7.42 (4H, m). MS m/z (%) 377 (Mþ, 0.6), 276 (100), 91 (40).
Calcd for C25H31NO2: M, 377.2355. Found: m/z 377.2350.
(2H, m), 2.06e2.18 (2H, m), 2.42 (3H, s), 2.53e2.72 (2H, m), 2.90
(1H, d, J¼16.2 Hz), 2.96 (3H, s), 3.07 (3H, s), 3.40 (1H, d, J¼16.1 Hz),
5.27 (1H, s), 7,30 (2H, d, J¼7.8 Hz), 7.68 (2H, d, J¼8.2 Hz). MS m/z (%)
327 (Mþ, 0.7), 188 (60), 152 (43), 139 (14), 72 (100). Calcd for
C16H22ClNO2S: M, 327.1060. Found: m/z 327.1057.
3.1.46. tert-Butyl [3,3-bis(ethoxymethyl)bicyclo[2.1.0]pent-1-yl]-N,N-
dibenzylaminoacetate (38a). Colorless oil; IR (neat) 2976, 2931, 2861,
1728 (CO),1495,1455,1368,1134,1109 (COC), 746, 699 cmꢀ1; 1H NMR
3.1.53. 2-{1-[Chloro(p-tolylsulfinyl)methyl]cyclobutyl}-N,N-dime-
thylpropionamide (41d). Colorless oil (about 2:1 mixture of two
diastereomers); IR (neat) 2945, 1634 (CO), 1494, 1399, 1083, 1055
d
0.85e0.90 (1H, m), 1.09 (3H, t, J¼7.0 Hz), 1.11 (1H, d, J¼5.1 Hz), 1.14
(SO) cmꢀ1
;
1H NMR
d
1.32 (1.0H, d, J¼6.8 Hz), 1.41 (2.0H, d,
(3H, t, J¼7.0 Hz),1.43 (9H, s),1.41e1.47 (1H, m),1.52e1.58 (1H, m),1.72
(1H, dd, J¼11.3, 1.8 Hz), 3.12 (1H, d, J¼9.5 Hz), 3.24 (1H, d, J¼9.5 Hz),
3.33e3.50 (6H, m), 3.74 (1H, s), 3.75 (2H, d, J¼14.2 Hz), 4.13 (2H, d,
J¼14.2 Hz), 7.19e7.24 (2H, m), 7.26e7.32 (4H, m), 7.37 (4H, d,
J¼7.2 Hz). MS m/z (%) 493 (Mþ, 0.3), 392 (100), 254 (33), 91 (76). Calcd
for C31H43NO4: M, 493.3192. Found: m/z 493.3196.
J¼7.0 Hz), 1.79e2.08 (2.0H, m), 2.42 (2.0H, s), 2.43 (1.0H, s),
2.32e2.61 (4.0H, m), 2.86 (1.0H, s), 2.96 (2.0H, s), 3.12 (1.0H, s), 3.18
(2.0H, s), 3.55 (0.33H, q, J¼6.8 Hz), 3.75 (0.67H, q, J¼7.0 Hz), 4.72
(0.33H, s), 4.83 (0.67H, s), 7.28e7.34 (2.0H, m), 7.63 (1.33H, d,
J¼8.2 Hz), 7.74 (0.67H, d, J¼8.2 Hz). MS m/z (%) 341 (Mþ, 0.1), 202
(40), 166 (49), 139 (22), 123 (12), 91 (17), 72 (100). Calcd for
C17H24ClNO2S: M, 341.1216. Found: m/z 341.1216.
3.1.47. tert-Butyl [3,3-bis(3-phenylpropoxymethyl)bicyclo[2.1.0]pent-
1-yl]-N,N-dibenzylaminoacetate (38b). Colorless oil; IR (neat) 2930,
3.1.54. [4,4-Bis(ethoxymethyl)cyclopent-1-enyl]-N,N-dimethylacet-
2857, 1727 (CO), 1495, 1455, 1367, 1133 (COC), 745, 699 cmꢀ1
;
1H
amide (42a). Colorless oil; IR (neat) 2975, 2852, 1646 (CO), 1395,
NMR
d
0.87e0.93 (1H, m), 1.02 (1H, d, J¼5.0 Hz), 1.42 (9H, s),
1111 (COC) cmꢀ1; 1H NMR
d
1.16 (6H, t, J¼7.0 Hz), 2.17e2.24 (4H, m),
1.44e1.57 (2H, m), 1.71e1.90 (5H, m), 2.55e2.68 (4H, m), 3.13 (1H,
d, J¼9.5 Hz), 3.25 (1H, d, J¼9.5 Hz), 3.32e3.53 (6H, m), 3.77 (2H, d,
J¼14.2 Hz), 3.78 (1H, s), 4.13 (2H, d, J¼14.2 Hz), 7.10e7.31 (16H, m),
7.38 (4H, d, J¼7.0 Hz). MS m/z (%) 673 (Mþ, 1), 572 (100), 254 (34),
91 (68). Calcd for C45H55NO4: M, 673.4131. Found: m/z 673.4122.
2.95 (3H, s), 2.99 (3H, s), 3.10 (2H, s), 3.33 (4H, s), 3.48 (4H, q,
J¼7.0 Hz), 5.28e5.32 (1H, m). MS m/z (%) 269 (Mþ, 10), 177 (28), 164
(88), 91 (12), 72 (100). Calcd for C15H27NO3: M, 269.1991. Found:
m/z 269.1989.
3.1.55. [4,4-Bis(3-phenylpropoxymethyl)cyclopent-1-enyl]-N,N-di-
3.1.48. Compound (39). Colorless oil; [
a
a
]
]
29 ꢀ24.1 (c 0.48, EtOH).
methylacetamide (42b). Colorless oil; IR (neat) 2928, 2854, 1646
D
(CO), 1497, 1455, 1395, 1112 (COC), 748, 700 cmꢀ1 1H NMR
; d 1.87
3.1.49. Compound (40). Colorless oil; [
30 ꢀ5.6 (c 0.35, EtOH).
(4H, tt, J¼7.6, 6.4 Hz), 2.19e2.28 (4H, m), 2.67 (4H, t, J¼7.6 Hz), 2.94
(3H, s), 2.99 (3H, s), 3.11 (2H, s), 3.35 (4H, s), 3.43 (4H, t, J¼6.4 Hz),
5.32 (1H, br s), 7.14e7.22 (6H, m), 7.23e7.31 (4H, m). MS m/z (%) 449
(Mþ, 38), 313 (10), 177 (60), 164 (100), 91 (68), 72 (61). Calcd for
C29H39NO3: M, 449.2930. Found: m/z 449.2935.
D
3.1.50. {1-[Chloro(p-tolylsulfinyl)methyl]-3,3-bis(ethoxymethyl)cy-
clobutyl}-N,N-dimethylacetamide (41a). Colorless oil (about 4:1
mixture of two diastereomers); IR (neat) 2975, 2933, 2869, 1645
(CO), 1494, 1398, 1107 (COC), 1054 (SO), 812, 753 cmꢀ1 1H NMR
;
d
1.10 (2.4H, t, J¼7.0 Hz), 1.13 (0.6H, t, J¼7.0 Hz), 1.18 (2.4H, t,
3.1.56. Cyclopent-1-enyl-N,N-dimethylacetamide
(42c). Colorless
1.85e1.94
J¼7.0 Hz), 1.21 (0.6H, t, J¼7.0 Hz), 2.09 (0.2H, d, J¼13.0 Hz), 2.14
oil; IR (neat) 2931, 2846, 1651 (CO), 1398 cmꢀ1; 1H NMR
d

1112
T. Satoh et al. / Tetrahedron 67 (2011) 1102e1113
(2H, m), 2.27e2.38 (4H, m), 2.95 (3H, s), 3.00 (3H, s), 3.15 (2H, s),
5.43e5.46 (1H, m). MS m/z (%) 153 (Mþ, 46), 72 (100). Calcd for
C9H15NO: M, 153.1154. Found: m/z 153.1149.
3.41 (4H, t, J¼6.4 Hz), 3.86 (2H, s), 5.36 (1H, br s), 7.14e7.21 (6H, m),
7.24e7.31 (4H, m), 7.47e7.55 (2H, m), 7.57e7.64 (1H, m), 7.84e7.91
(2H, m). MS m/z (%) 518 (Mþ, 1), 377 (26), 241 (13), 105 (29), 91
(100). Calcd for C32H38O4S: M, 518.2491. Found: m/z 518.2487.
3.1.57. 2-Cyclopent-1-enyl-N,N-dimethylpropionamide
(42d). Colorless oil; IR (neat) 2933, 2852, 1651 (CO), 1396, 1144,
3.1.64. {1-[Chloro(p-tolylsulfinyl)methyl]-3,3-bis(ethoxymethyl)cy-
clobutyl}acetonitrile (45). Colorless oil (about 2:1 mixture of two
diastereomers); IR (neat) 2975, 2933, 2870, 2244 (CN), 1378, 1106
1075 cmꢀ1; 1H NMR
d
1.24 (3H, d, J¼6.8 Hz), 1.86 (2H, q, J¼7.5 Hz),
2.24e2.34 (4H, m), 2.95 (3H, s), 2.99 (3H, s), 3.47 (1H, q, J¼6.8 Hz),
5.42e5.44 (1H, m). MS m/z (%) 167 (Mþ, 49), 95 (20), 72 (100). Calcd
for C10H17NO: M, 167.1310. Found: m/z 167.1310.
(COC), 1057 (SO), 812 cmꢀ1
;
1H NMR
d
1.11 (2.0H, t, J¼7.0 Hz), 1.13
(1.0H, t, J¼7.0 Hz), 1.20 (3.0H, t, J¼7.0 Hz), 2.14 (0.33H, d, J¼13.5 Hz),
2.20 (0.67H, d, J¼13.4 Hz), 2.23 (0.67H, d, J¼13.8 Hz), 2.36 (0.67H, d,
J¼13.4 Hz), 2.29e2.39 (0.67H, m), 2.43 (1.0H, s), 2.44 (2.0H, s), 2.55
(0.33H, d, J¼13.5 Hz), 2.78 (0.67H, d, J¼13.8 Hz), 2.99 (0.33 H, d,
J¼17.4 Hz), 3.08 (0.67H, d, J¼17.0 Hz), 3.16 (0.33H, d, J¼17.4 Hz), 3.23
(0.67H, d, J¼17.0 Hz), 3.32 (1.3H, s), 3.28e3.32 (0.33H, m),
3.38e3.60 (6.3H, m), 5.30 (0.33H, s), 5.38 (0.67H, s), 7.34 (2.0H, d,
J¼8.1 Hz), 7.48 (0.66H, d, J¼8.1 Hz), 7.72 (1.3H, d, J¼8.1 Hz). MS m/z
(%) 397 (Mþ, 1), 258 (47), 212 (19), 176 (47), 140 (100), 132 (55), 118
(94), 91 (49), 59 (95). Calcd for C20H28ClNO3S: M, 397.1478. Found:
m/z 397.1485.
3.1.58. {1-[Chloro(p-tolylsulfinyl)methyl]-3,3-bis(ethoxymethyl)cy-
clobutyl}methyl phenyl sulfone (43a). Colorless oil; IR (neat) 2975,
2932, 2870, 1447, 1308 (SO2), 1147, 1107 (COC), 1086, 1054 (SO),
754 cmꢀ1; 1H NMR
d
1.13 (6H, t, J¼7.0 Hz), 2.37 (1H, d, J¼13.7 Hz),
2.44 (3H, s), 2.55 (1H, d, J¼13.6 Hz), 2.57 (1H, d, J¼13.6 Hz), 2.77
(1H, d, J¼13.7 Hz), 3.38e3.57 (8H, m), 4.22 (1H, d, J¼14.0 Hz), 4.42
(1H, d, J¼14.0 Hz), 5.84 (1H, s), 7.34 (2H, d, J¼8.1 Hz), 7.54e7.69 (3H,
m), 7.82 (2H, d, J¼8.1 Hz), 7.98e8.04 (2H, m). MS (FAB) m/z (%) 513
([MþH]þ, 100), 233 (15), 185 (12), 139 (47), 91 (42), 59 (21). Calcd
for C25H34ClO5S2: MþH, 513.1536. Found: m/z 513.1537.
3.1.65. [4,4-Bis(ethoxymethyl)cyclopent-1-enyl]acetonitrile
3.1.59. {1-[Chloro(p-tolylsulfinyl)methyl]-3,3-bis(3-phenyl-
propoxymethyl)cyclobutyl}methyl phenyl sulfone (43b). Colorless
oil; IR (neat) 2933, 2861, 1496, 1447, 1308 (SO2), 1147, 1111 (COC),
(46). Colorless oil; IR (neat) 2975, 2852, 2251 (CN),1376,1111 (COC)
cmꢀ1; 1H NMR
d
1.17 (6H, t, J¼7.0 Hz), 2.20e2.27 (4H, m), 3.08 (2H,
br s), 3.33 (4H, s), 3.49 (4H, q, J¼7.0 Hz), 5.60e5.65 (1H, m). MS m/z
(%) 223 (Mþ, 2),177 (19),131 (51),117 (55), 91 (73), 79 (37), 59 (100).
Calcd for C13H21NO2: M, 223.1572. Found: m/z 223.1574.
1086, 1054 (SO), 751 cmꢀ1; 1H NMR
d 1.77e1.91 (4H, m), 2.40 (3H,
s), 2.40e2.49 (1H, m), 2.62 (4H, t, J¼7.8 Hz), 2.54e2.66 (2H, m), 2.84
(1H, d, J¼13.4 Hz), 3.35e3.56 (8H, m), 4.17 (1H, d, J¼13.8 Hz), 4.41
(1H, d, J¼13.8 Hz), 5.87 (1H, s), 7.09e7.33 (12H, m), 7.41e7.49 (2H,
m), 7.53e7.61 (1H, m), 7.81 (2H, d, J¼8.2 Hz), 7.93e7.99 (2H, m). MS
(FAB) m/z (%) 693 ([MþH]þ, 33),143 (12),139 (18),119 (41),105 (13),
91 (100). Calcd for C39H46ClO5S2: MþH, 693.2475. Found: m/z
693.2475.
3.1.66. 5,5-Bis(ethoxymethyl)spiro[2.3]hexane-1-carbonitrile
(47). Colorless oil; IR (neat) 2975, 2931, 2858, 2235 (CN), 1378, 1109
(COC) cmꢀ1
;
1H NMR
d
1.06 (1H, t, J¼5.6 Hz), 1.12 (1H, dd, J¼8.8,
5.6 Hz), 1.20 (3H, t, J¼7.0 Hz), 1.21 (3H, t, J¼7.0 Hz), 1.32 (1H, dd,
J¼8.8, 5.7 Hz), 1.99 (1H, d, J¼12.1 Hz), 2.06 (1H, d, J¼12.1 Hz), 2.08
(1H, d, J¼12.4 Hz), 2.23 (1H, d, J¼12.4 Hz), 3.46 (2H, s), 3.48 (2H, s),
3.52 (2H, q, J¼7.0 Hz), 3.53 (2H, q, J¼7.0 Hz). MS m/z (%) 223 (Mþ, 2),
164 (22), 149 (27), 129 (40), 118 (25), 109 (33), 93 (41), 79 (31), 59
(100). Calcd for C13H21NO2: M, 223.1572. Found: m/z 223.1574.
3.1.60. {1-[Chloro(p-tolylsulfinyl)methyl]cyclobutyl}methyl
sulfone (43c). Colorless oil; IR (neat) 2978, 1447, 1309 (SO2), 1145,
1085, 1051 (SO), 755 cmꢀ1; 1H NMR
1.99e2.29 (4H, m), 2.44 (3H,
phenyl
d
s), 2.66e2.78 (2H, m), 3.62 (1H, d, J¼14.2 Hz), 4.52 (1H, d,
J¼14.1 Hz), 5.57 (1H, s), 7.35 (2H, d, J¼8.3 Hz), 7.56e7.69 (3H, m),
7.80 (2H, d, J¼8.0 Hz), 8.03 (2H, d, J¼8.0 Hz). MS (FAB) m/z (%) 397
([MþH]þ, 100), 143 (76), 139 (28), 79 (69), 55 (34). Calcd for
C19H22ClO3S2: MþH, 397.0699. Found: m/z 397.0694.
Acknowledgements
This work was supported by a Grant-in-Aid for Scientific Re-
search No. 19590018 and 22590021 from the Ministry of Education,
Culture, Sports, Science and Technology, Japan, and TUS Grant for
Research Promotion from Tokyo University of Science, which are
gratefully acknowledged.
3.1.61. 1-{1-[Chloro(p-tolylsulfinyl)methyl]cyclobutyl}ethyl
sulfone (43d). Main product: colorless oil; IR (neat) 2942, 1447,
1305 (SO2), 1141, 1083, 1048 (SO), 761 cmꢀ1; 1H NMR
1.53 (3H, d,
phenyl
d
J¼7.0 Hz), 1.92e2.11 (2H, m), 2.36e2.43 (1H, m), 2.45 (3H, s),
2.59e2.68 (1H, m), 2.71e2.80 (1H, m), 2.89e2.97 (1H, m), 4.86 (1H,
q, J¼7.0 Hz), 6.26 (1H, s), 7.36 (2H, d, J¼7.8 Hz), 7.55e7.67 (3H, m),
7.85 (2H, d, J¼8.2 Hz), 7.98e8.01 (2H, m). MS (FAB) m/z (%) 411
([MþH]þ, 100), 271 (12), 241 (10), 149 (41), 143 (36), 93 (57). Calcd
for C20H24ClO3S2: MþH, 411.0855. Found: m/z 411.0853.
References and notes
1. Some selected reviews for the ring enlargement reactions: (a) Hiyama, T.;
Nozaki, H. J. Syn. Org. Chem. Jpn. 1977, 35, 979; (b) Krow, G. R. Tetrahedron 1987,
43, 3; (c) Hesse, M. Ring Enlargement in Organic Chemistry; VHC: Weinheim,
1991; (d) Roxburg, C. J. Tetrahedron 1993, 49, 10749; (e) Dowd, P.; Zhang, W.
Chem. Rev. 1993, 93, 2091; (f) Tochtermann, W.; Kraft, P. Synlett 1996, 1029; (g)
Satoh, T. J. Syn. Org. Chem. Jpn. 2009, 67, 381.
2. (a) Villieras, J.; Bacquet, C.; Normant, J. F. Organomet. Chem. 1972, 40, C1; (b)
Villieras, J.; Bacquet, C.; Masure, D.; Normant, J. F. Organomet. Chem. 1973, 50,
C7.
3.1.62. [4,4-Bis(ethoxymethyl)cyclopent-1-enyl]methyl phenyl sul-
fone (44a). Colorless oil; IR (neat) 2975, 2854, 1447, 1309 (SO2),
1153, 1111 (COC), 1087, 742 cmꢀ1
;
1H NMR
d
1.17 (6H, t, J¼7.0 Hz),
2.17 (2H, br s), 2.27 (2H, br s), 3.25 (4H, s), 3.47 (4H, q, J¼7.0 Hz),
3.85 (2H, s), 5.34 (1H, br s), 7.50e7.58 (2H, m), 7.61e7.67 (1H, m),
7.85e7.90 (2H, m). MS m/z (%) 338 (Mþ, 0.8), 197 (28), 151 (24), 105
(100), 93 (32), 91 (46), 77 (32), 59 (29). Calcd for C18H26O4S: M,
338.1552. Found: m/z 338.1552.
3. (a) Kobrich, G.; Grosser, J. Tetrahedron Lett. 1972, 13, 4117; (b) Kobrich, G.;
Grosser, J. Chem. Ber. 1973, 106, 2626.
4. (a) Taguchi, H.; Yamamoto, H.; Nozaki, H. Tetrahedron Lett. 1972, 13, 4661; (b)
Taguchi, H.; Yamamoto, H.; Nozaki, H. J. Am. Chem. Soc. 1974, 96, 6510; (c) Ta-
guchi, H.; Yamamoto, H.; Nozaki, H. Tetrahedron Lett. 1976, 17, 2617; (d) Taguchi,
H.; Yamamoto, H.; Nozaki, H. Bull. Chem. Soc. Jpn. 1977, 50, 1592.
5. Hiyama, T.; Shinoda, M.; Nozaki, H. Tetrahedron Lett. 1979, 20, 3529.
6. Abraham, W. D.; Bhupathy, M.; Cohen, T. Tetrahedron Lett. 1987, 28, 2203.
7. (a) Satoh, T.; Miyashita, K. Tetrahedron Lett. 2004, 45, 4859; (b) Miyashita, K.;
Satoh, T. Tetrahedron 2005, 61, 5067; (c) Satoh, T.; Tanaka, S.; Asakawa, N. Tet-
rahedron Lett. 2006, 47, 6769; (d) Tanaka, S.; Anai, T.; Tadokoro, M.; Satoh, T.
Tetrahedron 2008, 64, 7199.
3.1.63. [4,4-Bis(3-phenylpropoxymethyl)cyclopent-1-enyl]methyl
phenyl sulfone (44b). Colorless oil; IR (neat) 2929, 2856, 1447, 1309
(SO2), 1152, 1115 (COC), 1087, 747 cmꢀ1
;
1H NMR
d
1.81e1.93 (4H,
m), 2.18 (2H, br s), 2.29 (2H, br s), 2.67 (4H, t, J¼7.6 Hz), 3.27 (4H, s),

T. Satoh et al. / Tetrahedron 67 (2011) 1102e1113
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8. (a) Satoh, T. Chem. Soc. Rev. 2007, 36, 1561; (b) Satoh, T. In The Chemistry of
Organomagnesium Compounds; Rappoport, Z., Marek, I., Eds.; John Wiley: Chi-
chester,UK, 2008; pp 717e769.
Chem., Int. Ed. 2000, 39, 3072; (c) Satoh, T.; Matsue, R.; Fujii, T.; Morikawa, S.
Tetrahedron 2001, 57, 3891; (d) Hoffmann, R. W. Chem. Soc. Rev. 2003, 32, 225.
16. Yamashita, H.; Satoh, T. Tetrahedron 2009, 65, 613.
9. (a) Satoh, T.; Ogata, S.; Wakasugi, D. Tetrahedron Lett. 2006, 47, 7249; (b) Ogata,
S.; Saitoh, H.; Wakasugi, D.; Satoh, T. Tetrahedron 2008, 64, 5711.
10. Preliminary results of this study were reported as a letter: Satoh, T.; Awata, Y.;
Ogata, S.; Sugiyama, S.; Tanaka, M.; Tori, M. Tetrahedron Lett. 2009, 50, 1961.
11. Kashima, H.; Kawashima, T.; Wakasugi, D.; Satoh, T. Tetrahedron 2007, 63,
3953.
17. (a) Kido, M.; Sugiyama, S.; Satoh, T. Tetrahedron: Asymmetry 2007, 18, 1934; (b)
Sugiyama, S.; Nakaya, N.; Satoh, T. Tetrahedron: Asymmetry 2008, 19, 401.
18. Satoh, T.; Oohara, T.; Ueda, Y.; Yamakawa, K. J. Org. Chem. 1989, 54, 3130.
19. Satoh, T.; Kamide, Y.; Sugiyama, S. Tetrahedron 2004, 60, 11805.
20. (a) Satoh, T.; Ota, H. Tetrahedron 2000, 56, 5113; (b) Wakasugi, D.; Satoh, T.
Tetrahedron 2005, 61, 1245.
12. Sugiyama, S.; Satoh, T. Tetrahedron: Asymmetry 2005, 16, 665.
13. Bernard, A. M.; Frongia, A.; Secci, F.; Piras, P. P. Chem. Commun. 2005, 3853.
14. Ogata, S.; Masaoka, S.; Sakai, K.; Satoh, T. Tetrahedron Lett. 2007, 48, 5017 The
relative stereochemistry of the 2-phenylethyl group was not determined.
15. (a) Satoh, T.; Kobayashi, S.; Nakanishi, S.; Horiguchi, K.; Irisa, S. Tetrahedron
1999, 55, 2515; (b) Hoffmann, R. W.; Holzer, B.; Knopff, O.; Harms, K. Angew.
21. Saitoh, H.; Satoh, T. Tetrahedron Lett. 2010, 51, 3380.
22. Gadwood, R. C.; Mallick, I. M.; DeWinter, A. J. J. Org. Chem. 1987, 52, 774.
23. Ono, N.; Hamamoto, I.; Kawai, T.; Kaji, A.; Tamura, R.; Kakihana, M. Bull. Chem.
Soc. Jpn. 1986, 59, 405.
24. Tamura, R.; Kai, Y.; Kakihana, M.; Hayashi, K.; Tsuji, M.; Nakamura, T.; Oda, D.
J. Org. Chem. 1986, 51, 4375.