Investigation of intramolecular Pauson-Khand reaction of 2-aryl-1,6- and 1-methyl-1,7-enynes (exo-olefins) and 1-phenyl-1-octen-7-yne (endoolefin)

Article abstract of DOI:10.3987/COM-03-9993

The intramolecular Pauson-Khand reaction of various 2-aryl-1-hepten-6-ynes and its aza-derivatives (exo-olefins) efficiently produced arylbicyclo[3.3.0]octenones and azaoctenone bearing quaternary carbon centers at angular positions in good yields. Although a similar reaction of 2-phenyl-1-octen-7-yne (exo-olefin), which is a homologue of 2-phenyl-1-hepten-6-yne, did not take place, the reaction of the methyl derivatives smoothly proceeded. However, the reaction of regioisomeric 1-phenyl-1-octen-7-yne (endo-olefin) afforded the desired product in moderate yields.

Full text of DOI:10.3987/COM-03-9993

HETEROCYCLES, Vol. 63, No. 4, 2004, pp. 827 - 844
Received, 18th December, 2003, Accepted, 23rd January, 2004, Published online, 30th January, 2004
INVESTIGATION OF INTRAMOLECULAR PAUSON-KHAND
REACTION OF 2-ARYL-1,6- AND 1-METHYL-1,7-ENYNES
(EXO-OLEFINS) AND 1-PHENYL-1-OCTEN-7-YNE (ENDO-
OLEFIN)
Miyuki Ishizaki,* Hiroshi Satoh, Osamu Hoshino, Kiyoshi Nishitani, and
Hiroshi Hara*
Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641,
Yamazaki, Noda-shi, Chiba 278-8510, Japan
Abstract – The intramolecular Pauson-Khand reaction of various 2-aryl-1-hepten-
6-ynes and its aza-derivatives (exo-olefins) efficiently produced aryl-
bicyclo[3.3.0]octenones and azaoctenone bearing quaternary carbon centers at
angular positions in good yields. Although a similar reaction of 2-phenyl-1-octen-
7-yne (exo-olefin), which is a homologue of 2-phenyl-1-hepten-6-yne, did not
take place, the reaction of the methyl derivatives smoothly proceeded. However,
the reaction of regioisomeric 1-phenyl-1-octen-7-yne (endo-olefin) afforded the
desired product in moderate yields.
Since the first report on the Pauson-Khand reaction, the reaction has been widely used as one of the
powerful methods for the construction of cyclopentenone derivatives.1 The usefulness of the reaction has
been recognized by a large number of applications to the total synthesis of natural products.2 However,
most of the substrates used were enynes containing endo-olefins, regardless of the cyclic or acyclic
system. Recent studies3 in our laboratory revealed a convenient synthesis of polycyclic compounds by the
reaction of exo-cyclic olefins. One of the advantages in the reaction is the facile construction of a tricyclic
skeleton containing quaternary carbon center(s), which could not be synthesized from endo-cyclic
olefins.3a,b Some other features are easy access to spirobicyclic3c,d and tricyclic3e-g skeletons in natural
products such as magellanine and cedranediol. Contrary to the cyclic enynes, although acyclic enynes
having exo-olefin moiety have more flexible conformers, the reaction affords direct bicyclic compounds
bearing quaternary carbon centers at angular positions. Furthermore, they can be useful intermediates for
the total synthesis of natural products. However, as for the reaction of acyclic exo-olefins, the reaction of

enynes containing aromatic substituents has not been
reported except for only a few works on derivatives
bearing aliphatic substituents [A (n = 1); R = Me,
R’ = H, X = C(CO2Me)24a-g or R = CH2OBn, R’ = H,
Ar(R)
Ar(R)
Pauson-Khand
reaction
X
X
O
R'
n
n
R'
B
A
4h,i
X = C(CO2Et)2 in Scheme 1]. In addition, no
Ar = Aromatic group; R = Aliphatic group
X = C(CO Me) or NTs, n = 1 or 2, R' = H or TMS
2
2
reports have appeared in regard to the reaction of
1,7-enynes (A; n = 2).5 Thus, an examination of the
Pauson-Khand reaction of acyclic 2-aryl-1-hepten-6-
ynes and their homologues (A, C) seemed to be
quite an interesting issue. Here, we wish to report
fully on the intramolecular Pauson-Khand reaction
of acyclic exo-olefins (A, C) having aromatic
substituents to give the corresponding bicyclic
compounds (B, D) bearing quaternary carbon centers
and the reaction of regioisomeric acyclic endo-
Ph
Me
Ph
Pauson-Khand
reaction
X = C(CO Me) or NTs
Me
X
X
O
C
D
2
2
R
R
E
Pauson-Khand
reaction
E
E
O
E
E
F
E = CO Me
2
R = Ph, Me
Scheme 1
olefins (E) to give the cyclized products (F) (Scheme 1).6
Various Pauson-Khand precursors (2a-k) bearing the alkylidene group were synthesized as follows
(Scheme 2). The reaction of dimethyl propargylmalonate (1)7 with 2-aryl-3-iodopropenes (3a,b), which
were easily obtained from the corresponding alcohols,8 afforded 2-aryl-1,6-enynes (2a,b) in high yield. A
similar reaction of N-propargyltosylamide (5)9 furnished 2h. Enynes (2c-f,i) containing the phenyl, 3,4-
methylenedioxyphenyl, furyl or thienyl group were attained by the coupling of 1 or 5 with aryl
bromomethyl ketones,10 followed by Wittig olefination. A pyridyl-substituted enyne (2g) was synthesized
by the Mitsunobu reaction of 1 with 2-pyridyl-2-propenol11 in the presence of N,N,N’,N’-
tetramethylazodicarboxamide (TMAD).12 TMS-substituted alkynes (2j,k) were obtained by the reaction
of 2a and 2h with TMSCF3 in the presence of CsF.13
With enynes in hand, the intramolecular Pauson-Khand reaction of exo-enynes (2a-j) was examined by
following three methods after treatment with Co2(CO)8; a reaction with 9-12 equivalents of NMO (N-
methylmorpholine N-oxide)14a in CH2Cl2 at room temperature (Method A); refluxing in toluene (Method
B); heating at 83˚C with BuSMe14b in 1,2-dichloroethane (Method C). The results are shown in Table 1.
The reaction of α-styryl-type enynes (2a,d,h) gave corresponding bicyclic cyclopentenones (6a,d,h) in
moderate to good yields (40-73%) by Methods A-C. However, a similar reaction of a naphthyl derivative
(2b) resulted in formation of the product (6b) in low to moderate yields (4-57%). The difference of the
yields among 2a,b,d by Method A can be explained by considering that the bulky naphthyl group in 2b
would interfere with the proximity of the alkyne-cobalt complex moiety and the olefinic part owing to a

CsF
TMSCF
Ph
Ar
H
1) NaH, DMF
MeO C
2
3
MeO C
MeO C
2
2
MeO C
2
2) ArC(=CH )CH I (3a,b)
MeO C
MeO C
2
2
THF, 99%
2
2
TMS
1
2a : Ar = Ph (96%)
2b : Ar = 1-naphthyl (99%)
2j
Ph
Ph
t-BuOK
1) NaH, DMF
PPh EtBr
3
MeO C
MeO C
2
2
1
1
Me
O
MeO C
MeO C
2
2) PhC(=O)CH Br
2
2
THF, 86%
94%
4c
2c (E/Z = 72/28)
Ar
Ar
t-BuOK
PPh MeBr
1) NaH, DMF
3
MeO C
MeO C
2
2
O
MeO C
MeO C
2
2
THF
2) ArC(=O)CH Br
2
2d: Ar = 3,4-methylenedioxyphenyl (95%)
2e : Ar = 2-furyl (88%)
4d: Ar = 3,4-methylenedioxyphenyl (45%)
4e : Ar = 2-furyl (90%)
2f : Ar = 2-thienyl (79%)
4f : Ar = 2-thienyl (80%)
TMAD, Bu P
3
N
2-PyC(=CH )CH OH
MeO C
2
2
2
1
MeO C
2
benzene, 72%
2g
Ph
Ph
K CO
PhC(=CH )CH I (3a)
2
3
CsF
TMSCF
TsHN
2
2
3
TsN
TsN
TsN
DMF, 74%
THF, 96%
TMS
5
5
2h
BuLi
2k
Ph
K CO , TBAI
Ph
2
3
PhC(=O)CH Br
2
PPh EtBr
3
Me
2i (E/Z = 22/78)
TsN
O
DMF, 93%
THF, 76%
4i
Scheme 2
low reaction temperature. The reaction of other enynes (2e-g) containing heterocycles such as furan,
thiophene and pyridine also smoothly proceeded to afford desired bicyclic compounds (6e-g) in moderate
to good yields (45-79%). In the case of trisubstituted exo-olefins (2c,i), cyclized products (6c,i) were
obtained as a mixture of stereoisomers in moderate yields by Method C. The stereochemistry of the
products was determined by 1H-NMR spectrometry. Thus, chemical shifts of the Me group at C4 (δ 1.24
for 6cβ, δ 1.13 for 6iβ) were observed at a lower field than those of their isomers (δ 0.64 for 6cα, δ 0.65
for 6iα) due to anisotropic effect caused by benzene rings. The ratio of stereoisomers was estimated by
the integration of peaks due to the Me group at C4 in its 1H NMR spectrum. Unfortunately, the reaction of
TMS-substituted enynes (2j,k) failed to cyclize and only starting enynes, which were produced by
decomplexation during the reaction, were recovered in quantitative yields. From the results mentioned
above, it was found that thermal conditions (Methods B and C) were superior to an oxidative condition

Ar
Ar
Me
Me
Ph
Ph
E
E
Pauson-Khand
reaction
E
E
E
E
E
E
R
4
4
O
O
O
R'
R'
6a,b,d-g,j
6cα
6cβ
2a-g, j
E = CO Me
2
R = H or Me, R' = H or TMS
Ph
Me
Me
Ph
Ph
Ph
Pauson-Khand
TsN
reaction
R
R'
4
4
TsN
O
TsN
TsN
O
O
R'
6iα
6iβ
6h,k
2h,i,k
Scheme 3
R = H or Me
R' = H or TMS
Table 1. Pauson-Khand reaction of exo-enynes (2a-i)
Entry
Substrate
Methoda
Time(h)
Product
Yield(%)
1
2
3
4
5
6
2a
2a
2a
2b
2b
2b
A
B
C
A
B
C
2
8
10
2
8
8
6a
6a
6a
6b
6b
6b
56
70
73
4
57
48
0b
7
8
2c
2c
A
B
2
8
6c
6c
18c,d
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
2c
2d
2d
2d
2e
2e
2e
2f
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
13
2
8
10
2.5
5
12
2
5
10
2
2
3
6c
6d
6d
6d
6e
6e
6e
6f
52c,e
40
62
66
66
70
79
49
62
66
45
46
51
61
60
64
2f
2f
6f
6f
2g
2g
2g
2h
2h
2h
6g
6g
6g
6h
6h
6h
2
8
10
25
26
27
2i
2i
2i
A
B
C
2
8
6i
6i
6i
0b
11f,g
56f,h
15
a) Method A; reaction with 9-12 eq. of NMO at rt in CH2Cl2. Method B; refluxing in toluene. Method C;
heating at 83˚C with BuSMe in 1,2-dichloroethane. b) Complex mixtures were formed. c) Combined
yield of 6cα and 6cβ. d) 6cα/6cβ = 54/46. e) 6cα/6cβ = 58/42. f) Combined yield of 6iα and 6iβ.
g) 6iα/6iβ = 85/15. h) 6cα/6cβ = 60/40.

(Method A) in the reaction of malonates (2a-g). On the other hand, in the reaction of tosylamide (2h), the
cyclized product (6h) was formed in similar yields (60-64%) without regard to Methods A-C.
Because there was only one report15 on the reaction of acyclic 1,7-enynes bearing the exo-methylene
group, we next investigated the reaction of the homologues of 2a (Scheme 4). Thus, the reaction of α-
R
R
1) NaH, DMF
O
Pauson-Khand
reaction
MeO C
2
MeO C
2
1
MeO C
R'
2) RC(=CH )CH CH I
MeO C
2
2
2
2
2
R'
9a : R = Ph, R' = H
7a : R = Ph, R' = H (70%)
7b : R = Ph, R' = SMe (93%)
7c : R = Ph, R' = TMS (99%)
8 : R = Me, R' = H (82%)
1) LDA
THF
2) MeSCN
TMSCF
CsF, THF
3
9b : R = Ph, R' = SMe
9c : R = Ph, R' = TMS
10 : R = Me, R' =H
R
R
MeO C
H
2
MeO C
2
1) NaH, DMF
2) RC(=CH )CH I
MeO C
Pauson-Khand
reaction
2
MeO C
2
MeO C
O
MeO C
2
2
2
2
14 : R = Ph
15 : R = Me
12 : R = Ph (88%)
13 : R = Me (85%)
11
Ph
H
Ph
1) NaH, DMF
2) (E)-PhCH=CHCH CH I
MeO C
Pauson-Khand
reaction
2
O
MeO C
1
2
MeO C
2
2
2
MeO C
2
67%
17
16
18
Ph
H
MeO C
MeO C
2
2
Ph
Pauson-Khand
reaction
1) NaH, DMF
MeO C
MeO C
2
O
2
11
2) (E)-PhCH=CHCH Cl
2
83%
19
Scheme 4
Table 2. Pauson-Khand reaction of exo- and endo-enynes (8, 13, 16, 18)
Entry
Substrate
Methoda
Time(h)
Product
Yield(%)
1
2
3
8
8
8
A
B
C
3
2
13
10
10
10
0b
28
5
4
5
13
13
A
B
2
7
15
15
0b
18
6
7
8
13
16
16
16
18
18
18
C
A
B
C
A
B
C
13
2
8
10
1
3
15
17
17
17
19
19
19
0b
41
16
65
62
48
63
9
10
11
12
5
a) See foot note in Table 1. b) Complex mixtures were formed.

styryl-type enynes (7a, 12) was examined. The
E'
H
Ph
substrates were synthesized in the usual manner from 1 E'
NOE
E
and 11.16 Unfortunately, the reaction of 7a and 12 by
H
O
E
17 : E = CO Me, E' = H
19 : E = H, E' = CO Me
2
H
2
Methods A-C resulted in the formation of complex
NOE
Figure 1
mixtures and failed to give the desired cyclopentenones
(9a, 14). Livinghouse17a and Magnus17b reported that the reaction of enynes bearing the methylthio or
trimethylsilyl group on terminal alkyne moiety improved the yields and stereoselectivity compared with
those of enynes having no substituted terminal alkyne. Thus, we carried out the reaction of such
substrates (7b,c), which were prepared according to the reported procedure.13,17b However, the reaction of
7b and 7c did not give cyclized products (9b,c) at all. To investigate the effect of substituents on alkenyl
moiety, a similar reaction of methyl derivatives (8, 13), which were prepared in a manner similar to that
noted for 7a, was performed (Table 2). As shown in Table 2, the reaction of 8 furnished 10 in 5-28%
yields under thermal conditions (Entries 2 and 3), although the reaction with NMO failed (Entry 1). A
similar reaction of 13 proceeded to give 15 in 18% yield only by Method B (Entry 5).
These findings promted us to examine the reaction of endo-type 1,7-enynes (16, 18), which were
regioisomers of 7a and 12, to compare the reactivity in the reaction, because there were very few
reports15,18 on the Pauson-Khand reaction of acyclic styryl endo-type 1,7-enynes. Interestingly, in the
reaction of 16, a cyclized product (17) was obtained in 16-65% yields under both oxidative and thermal
conditions (Table 2, Entries 7-9). In addition, the reaction of 18 furnished 19 in 48-63% yields (Entries
10-12). The stereochemistry of the products (17, 19) was determined by NOE experiments (Figure 1).
These results suggested that the steric factor around the olefinic moiety should be crucial. As depicted in
Scheme 5, the reaction of exo-enynes (7a, 8, 12, 13) could occur via the boat (C1) or chair (C2)
Co(CO)
R
2
E
E
Me
E'
E'
E'
E'
E
Co(CO)3
R
E
E'
Co(CO)3
O
E
E'
E
Co(CO)
2
R'
E
E
E'
E'
R
C2
10 : E = CO Me, E' = H
2
15 : E = H, E' = CO Me
7a : E = CO Me, E' = H, R = Ph
2
8 : E = CO Me, E' = H, R = Me
C1
2
2
12 : E = H, E' = CO Me, R = Ph
2
13 : E = H, E' = CO Me, R = Me
2
Co(CO)
Ph
2
E'
H
E
E'
E'
E
E'
Ph
E
Co(CO)3
Ph
O
E
E'
E
E
E'
H
16 : E = CO Me, E' = H
2
18 : E = H, E' = CO Me
C3
17 : E = CO Me, E' = H
2
19 : E = H, E' = CO Me
2
2
Scheme 5

conformational transition state. The former conformation (C1) would be excluded by high steric repulsion.
When the reaction proceeds via the chair conformer (C2), the bulky phenyl group has to set in an
undesired axial position. Thus, the cyclization of enynes (7a, 12) would not occur. Contrary to phenyl
derivatives, the reaction of enynes (8, 13) with a smaller methyl group could proceed via C2 to afford
cyclized products (10, 15), although in low yield. In the case of endo-enynes (16, 18), the reaction
proceeded via C3 to give adducts (17, 19) in moderate yields.
In conclusion, we have investigated the intramolecular Pauson-Khand reaction of various acyclic exo-
olefins bearing an aromatic substituent (2a-k) to give bicyclic cyclopentenones (6a-i) except for 6j and 6k.
In a similar reaction of 2-subsituted 1,7-enynes (exo-olefins) (7a-c, 8, 12, 13), phenyl derivatives (7a-c, 8)
failed to cyclize. However, methyl derivatives (8, 13) proceeded to afford adducts (10, 15). Contrary to 2-
phenyl-1,7-enynes (exo-olefins), the reaction of 1-phenyl-1,7-enynes (endo-olefins) (16, 18) yielded
cyclized products (17, 19). The present study revealed the nature of the reaction of acyclic exo- and endo-
enynes, and provides a convenient approach to bicyclic cyclopentenones (6a-g) having aromatic
substituents at their quaternary carbon center.
ACKNOWLEDGEMENTS
The authors are grateful to Mrs. F. Hasegawa of this faculty for her MS spectral measurement.
EXPERIMENTAL
General. All melting points were measured on a Yanagimoto melting point apparatus and are uncorrected.
1 13
IR spectra were obtained with a JASCO FT/IR-400. H and C NMR spectra were taken with a JEOL
1
13
EX-270 (270 MHz for H NMR and 67.5 MHz for C NMR) spectrometer in a CDCl3 solution with
tetramethylsilane as an internal standard. MS spectra were measured on a Hitachi M-80 or a JEOL JMS
D-300 spectrometer. Column chromatography was performed over silica gel (Merck Kiegelsel 60).
Preparative TLCs were run on a Merck 5744 plate. Organic extracts were dried over MgSO4.
General Procedure for Synthesis of Iodides (3a,b).
To a stirred mixture of 2-phenyl-2-propenol8a or 2-(α-naphthyl)-2-propenol8b (1 eq.), PPh3 (1.5 eq.) and
pyridine (2.5 eq.) in CH2Cl2 (10 mL per 1 mmol of the alcohol) at 0°C was added I2 (1.5 eq.) in one
portion. After the mixture was stirred for 2 h, the reaction was quenched with a 10% aqueous Na2S2O3
solution. The organic layer was washed with 1M HCl, water and brine, respectively, and dried.
Evaporation of the solvent in vacuo gave a residue, which was purified by column chromatography
(hexane) to give the corresponding iodides (3a,b).
3-Iodo-2-phenylpropene (3a); from 2-phenyl-2-propenol (0.375 g, 2.80 mmol), 3a (0.552 g, 80.0%) was

1
obtained as a pale yellow oil; H NMR δ 7.29-7.47 (5H, m), 5.52, 5.47 (each 1H, s), 4.31 (2H, s); IR
(neat) 3081, 2961, 1493 cm-1; MS m/z 244 (M+); HRMS m/z calcd for C9H9I (M+) 243.9749, found:
243.9740.
3-Iodo-2-(α-naphthyl)propene (3b); from 2-(α-naphthyl)-2-propenol (0.920 g, 5.0 mmol), 3b (1.040 g,
1
70.7%) was obtained as a pale yellow oil; H NMR δ 7.81-7.97 (3H, m), 7.37-7.52 (4H, m), 5.85, 5.25
(each 1H, s), 4.37 (2H, s); IR (neat) 3290, 2960, 1490 cm-1; MS m/z 294 (M+); HRMS m/z calcd for
C13H11I (M+) 293.9905, found: 293.9912.
General Procedure for Synthesis of Enynes (2a,b, 7a, 8, 12, 13, 16, 18). To a stirred mixture of NaH
(1.5 eq.) and 1 (1 eq.) or 11 (1 eq.) in DMF (10 mL per 1 mmol of 1 or 11) at 0°C was added a solution of
allyl iodide (1.2 eq.) or homoallyl iodide (1.2 eq.) in DMF (4.5 mL per 1 mmol of the iodide). Then, the
mixture was allowed to warm to rt and stirred overnight. After cooling at 0˚C, the reaction was quenched
with water. The mixture was extracted with ether. The organic extracts were washed with water and brine,
respectively, and dried. Evaporation of the solvent in vacuo gave a residue, which was purified by column
chromatography (hexane/AcOEt = 20 : 1 ~ 5 : 1) to furnish the corresponding enynes (2a,b, 7a, 8, 12, 13,
16, 18).
Dimethyl 2-(2-phenyl-2-propenyl)-2-(2-propynyl)malonate (2a); from 1 (0.310 g, 1.82 mmol), 2a
1
(0.502 g, 95.9%) was obtained as colorless crystals; mp 73˚C (hexane); H NMR δ 7.18-7.34 (5H, m),
5.31, 5.30 (each 1H, d, J = 1.7 Hz), 3.42 (6H, s), 3.33 (2H, s), 2.76 (2H, d, J = 2.6 Hz), 2.05 (1H, t, J =
2.6 Hz); 13C NMR δ 170.0, 143.8, 140.9, 128.1, 127.6, 126.9, 119.0, 79.2, 71.8, 56.4, 52.5, 36.9, 22.3; IR
(KBr) 3273, 2949, 2123, 1734 cm-1; MS m/z 286 (M+); HRMS m/z calcd for C17H18O4 (M+) 286.1203,
found: 286.1193.
Dimethyl 2-[2-(1-naphthyl-2-propenyl)]-2-(2-propynyl)malonate (2b); from 1 (0.425 g, 2.50 mmol),
1
2b (0.835 g, 99.4%) was obtained as colorless crystals; mp 85˚C (hexane); H NMR δ 8.01-8.04 (1H, m),
7.80-7.83 (1H, m), 7.73 (1H, d, J= 8.3 Hz), 7.45-7.52 (2H, m), 7.39 (1H, dd, J = 6.9, 8.3 Hz), 7.24 (1H,
dd, J = 1, 6.9 Hz), 5.63 (1H, d, J = 1 Hz), 5.34 (1H, d, J = 2 Hz), 3.48 (2H, d, J = 1 Hz), 3.25 (6H, s), 2.88
(2H, d, J = 2.6 Hz), 2.02 (1H, t, J = 2.6 Hz); 13C NMR δ 169.8, 143.0, 139.3, 133.6, 130.9, 128.3, 127.8,
126.1, 126.0, 125.7, 125.0, 122.0, 79.1, 71.8, 56.4, 52.3, 39.4, 22.4; IR (KBr) 3291, 2957, 2120, 1735
cm-1; MS m/z 336 (M+); HRMS m/z calcd for C21H20O4 (M+) 336.1362, found: 336.1370.
Dimethyl 2-(3-phenyl-3-butenyl)-2-(2-propynyl)malonate (7a); from 1 (0.500 g, 2.94 mmol), 7 (0.590
1
g, 70.4%) was obtained as colorless crystals; mp 44-45˚C; H NMR δ 7.51-7.54 (2H, m), 7.38-7.47 (3H,
m), 5.45, 5.24 (each 1H, s), 3.86 (6H, s), 3.02 (2H, d, J = 2.6 Hz), 2.52-2.59 (2H, m), 2.32-2.39 (2H, m),
2.13 (1H, t, J = 2.6 Hz); 13C NMR δ 170.6, 147.1, 140.5, 128.3, 127.5, 126.0, 122.9, 78.6, 71.6, 56.8, 52.8,
31.2, 29.8, 23.0; IR (KBr) 3282, 2952, 2121, 1753, 1733 cm-1; MS m/z 300 (M+); HRMS m/z calcd for
C18H20O4(M+) 300.1362, found: 300.1358.

Dimethyl 2-(3-methyl-3-butenyl)-2-(2-propynyl)malonate (8); from 1 (1.00 g, 5.88 mmol), 8 (1.16 g,
82.3%) was obtained as a colorless oil; 1H NMR δ 4.67, 4.66 (each 1H, s), 3.69 (6H, s), 2.79 (2H, d, J =
13
2.6 Hz), 2.12-2.18 (2H, m), 1.98 (1H, t, J = 2.6 Hz), 1.80-1.87 (2H, m), 1.68 (3H, s); C NMR δ 170.6,
144.5, 120.6, 78.7, 71.1, 67.0, 52.8, 32.1, 30.2, 22.9, 22.4; IR (neat) 3289, 2954, 2120, 1735, 1437 cm-1;
MS m/z 238 (M+); HRMS m/z calcd for C13H18O4 (M+) 238.1206, found: 238.1207.
Dimethyl 2-(3-butynyl)-2-(2-phenyl-2-propenyl)malonate (12); from 11 (0.184 g, 1.00 mmol), 12
1
(0.265 g, 88.3%) was obtained as a colorless oil; H NMR δ 7.26-7.29 (5H, m), 5.26, 5.14 (each 1H, s),
13
3.45 (6H, s), 3.18 (2H, s), 2.09 (4H, s), 1.91 (1H, br s); C NMR δ 170.6, 147.1, 140.5, 128.3, 127.5,
126.0, 112.9, 78.7, 71.6, 56.8, 52.8, 31.3, 29.8, 23.0; IR (neat) 3291, 2952, 2129, 1732 cm-1; MS m/z 300
(M+); HRMS m/z calcd for C18H20O4 (M+) 300.1362, found: 300.1369.
Dimethyl 2-(3-butynyl)-2-(2-methyl-2-propenyl)malonate (13); from 11 (0.920 g, 5.00 mmol), 13 (1.02
1
g, 85.4%) was obtained as colorless crystals; mp 41˚C; H NMR δ 4.89, 4.75 (each 1H, s), 3.73 (6H, s),
13
2.73 (2H, s), 2.17 (4H, s), 1.95 (1H, br s), 1.65 (3H, s); C NMR δ 171.5, 140.1, 116.0, 83.2, 68.7, 56.4,
52.5, 40.7, 31.6, 23.0, 14.1; IR (KBr) 3309, 2957, 2122, 1731 cm-1; MS m/z 238 (M+); HRMS m/z calcd
for C13H18O4 (M+) 238.1206, found: 238.1194.
Dimethyl 2-(4-phenyl-3-butenyl)-2-(2-propynyl)malonate (16); from 1 (0.187 g, 1.10 mmol), 16 (0.222
1
g, 67.1%) was obtained as colorless crystals; mp 67-68˚C (hexane); H NMR δ 7.17-7.35 (5H, m), 6.41
(1H, d, J = 15.8 Hz), 6.17 (1H, dt, J = 15.8, 6.4 Hz), 3.74 (6H, s), 2.89 (2H, d, J = 2.6 Hz), 2.23-2.27 (2H,
13
m), 2.16-2.20 (2H, m), 2.03 (1H, t, J = 2.6 Hz); C NMR δ 170.6, 137.4, 130.7, 128.9, 128.5, 127.1,
126.0, 78.7, 71.5, 56.6, 52.8, 31.6, 27.6, 23.0; IR (KBr) 3275, 2955, 1734 cm-1; MS m/z 300 (M+); HRMS
m/z calcd for C18H20O4 (M+) 300.1362, found: 300.1346.
Dimethyl 2-(3-butynyl)-2-(3-phenyl-2-propenyl)malonate (18); from 11 (0.368 g, 2.0 mmol), 18 (0.500
g, 83.3%) was obtained as a colorless oil; 1H NMR δ 7.19-7.34 (5H, m), 6.45 (1H, d, J = 15.6 Hz), 6.01
(1H, dd, J = 7.5, 15.6 Hz), 3.73 (6H, s), 2.08 (2H, dd, J = 7.5, 12.8 Hz), 2.20-2.25 (4H, m), 1.97 (1H, t, J
= 2.1 Hz); 13C NMR δ 171.1, 136.9, 134.2, 128.5, 127.5, 126.2, 123.4, 83.0, 78.8, 57.3, 52.5, 36.7, 31.7,
13.9; IR (neat) 3292, 2952, 2119, 1731 cm-1; MS m/z 300 (M+); HRMS m/z calcd for C18H20O4 (M+)
300.1362, found: 300.1366.
Dimethyl 2-(3-methylthio-2-propynyl)-2-(3-phenyl-3-butenyl)malonate (7b). To a solution of
diisopropylamine (130 µL, 0.916 mmol) in THF (6 mL) at –78˚C was added 1.59 M BuLi in hexane (0.58
mL, 0.92 mmol). After being stirred for 30 min, a solution of 7a (0.250 g, 0.83 mmol) in THF (4 mL) was
added over a period of 10 min and stirring was continued for an additional 30 min. Then, MeSCN (70 µL,
1.00 mmol) was added. The mixture was allowed to warm up to rt for 17 h. The reaction was quenched
with saturated aqueous NaHCO3 solution and the mixture was extracted with ether. The organic extracts
were washed with water and brine, respectively, and dried. Evaporation of the solvent in vacuo gave a

residue, which was purified by column chromatography (hexane/AcOEt = 5 : 1) to give 7b (0.270 g,
93.4%) as a pale yellow oil; 1H NMR δ 7.22-7.45 (5H, m), 5.33, 5.11 (each 1H, d, J = 1 Hz), 3.74 (6H, s),
13
3.00 (2H, s), 2.39-2.46 (2H, m), 2.27 (3H, s), 2.17-2.23 (2H, m); C NMR δ 170.6, 147.2, 140.5, 128.4,
127.5, 126.0, 112.9, 87.2, 74.2, 57.1, 52.7, 31.4, 29.9, 24.6, 19.2; IR 2952, 2193, 1734 cm-1; MS m/z 346
(M+); HRMS m/z calcd for C19H22O4S (M+) 346.1238, found: 346.1241.
Dimethyl 2-(3-trimethylsilyl-2-propynyl)-2-(3-phenyl-3-butenyl)malonate (7c). To a suspension of 7a
(0.250 g, 0.83 mmol) and CsF (0.003 g , 0.02 mmol) in THF (6 mL) at rt TMSCF3 (160 µL, 1.08 mmol)
was added. After being stirred for 30 min, the mixture was filtered and the filtrate was evaporated in
vacuo to give a residue, which was purified by column chromatography (hexane/AcOEt = 5 : 1) to afford
1
7c (0.307 g, 99.2%) as a colorless oil; H NMR δ 7.26-7.32, (2H, m), 7.13-7.25 (3H, m), 5.22 (1H, s),
5.00 (1H, d, J = 1 Hz), 3.63 (6H, s), 2.81 (2H, s), 2.29-2.36 (2H, m), 2.06-2.16 (2H, m), 0.00 (9H, s); 13C
NMR δ 170.7, 147.3, 140.6, 138.4, 137.6, 136.1, 122.9, 101.1, 88.4, 57.1, 52.8, 40.6, 30.0, 24.4, 0.1; IR
(neat) 2954, 2179, 1738, 1436 cm-1; MS m/z 372 (M+); HRMS m/z calcd for C21H28O4Si (M+) 372.1755,
found: 372.1762.
General Procedure for Synthesis of Ketones (4c-f). To a stirred mixture of NaH (1.5 eq.) and 1 (1 eq.)
in DMF (10 mL per 1 mmol of 1) at 0°C was added a solution of aryl bromomethyl ketone (1.2 eq.) in
DMF (3.0-5.5 mL per 1 mmol of the ketone). Then, the mixture was allowed to warm to rt and stirred
overnight. After cooling at 0˚C, the reaction was quenched with water. The mixture was extracted with
ether. A similar work-up, as noted above, gave a residue, which was purified by column chromatography
(hexane/AcOEt = 10 : 1 ~ 2 : 1) to give the corresponding ketones (4c-f).
Dimethyl 2-[2-phenyl-2-oxoethyl]-2-(2-propynyl)malonate (4c); from 1 (0.855 g, 5.0 mmol), 4c (1.369
g, 94.4%) was obtained as a colorless oil; 1H NMR δ 7.97-8.03 (2H, m), 7.56-7.63 (1H, m), 7.44-7.52 (2H,
m), 3.93 (2H, s), 3.77 (6H, s), 3.16 (2H, d, J = 2.7 Hz), 2.02 (1H, t, J = 2.7 Hz); 13C NMR δ 196.6, 169.7,
136.2, 133.5, 128.6, 128.1, 79.2, 71.8, 54.5, 53.1, 40.9, 23.3; IR (neat) 3282, 2954, 1746, 1684 cm-1; MS
m/z 288 (M+); HRMS m/z calcd for C16H16O5 (M+) 288.0998, found: 288.1011.
Dimethyl 2-[2-(3,4-methylenedioxyphenyl)-2-oxoethyl]-2-(2-propynyl)malonate (4d); from 1 (1.26 g,
1
7.41 mmol), 4d (1.10 g, 44.7%) was obtained as colorless crystals; mp 97-98˚C (AcOEt-hexane); H
NMR δ 7.63 (1H, dd, J = 1.7, 8.3 Hz), 7.44 (1H, d, J = 1.7 Hz), 6.86 (1H, d, J = 8.3 Hz), 6.05 (2H, s),
13
3.84 (2H, s), 3.77 (6H, s), 3.11 (2H, d, J = 2.6 Hz), 2.01 (1H, t, J = 2.6 Hz); C NMR δ 194.6, 169.8,
152.1, 148.2, 131.1, 124.6, 107.9, 107.8, 101.9, 79.3, 71.8, 54.6, 53.1, 40.7, 23.3 ; IR (KBr) 3258, 1754,
1742 cm-1; MS m/z 332 (M+); HRMS m/z calcd for C17H16O7 (M+) 332.0895, found: 332.0901.
Dimethyl 2-[2-(2-furyl-2-oxoethyl)]-2-(2-propynyl)malonate (4e); from 1 (0.043 g, 0.25 mmol), 4e
(0.063 g, 90.0%) was obtained as colorless crystals; mp 81-82˚C (AcOEt-hexane); 1H NMR δ 7.61 (1H, d,
J = 1.7 Hz), 7.26 (1H, d, J = 3.6 Hz), 6.56 (1H, dd, J = 1.7, 3.6 Hz), 3.77 (8H, s), 3.09 (2H, d, J = 2.6 Hz),

2.03 (1H, t, J = 2.6 Hz); 13C NMR δ 185.5, 169.5, 152.1, 146.8, 117.8, 112.4, 79.1, 71.9, 54.4, 53.2, 40.5,
23.5; IR (KBr) 3282, 2955, 1742 cm-1; MS m/z 278 (M+); HRMS m/z calcd for C14H14O6 (M+) 278.0789,
found: 278.0803.
Dimethyl 2-(2-propynyl)-2-[2-(2-thienyl-2-oxoethyl)]malonate (4f); from 1 (0.219 g, 1.29 mmol), 4f
(0.303 g, 79.9%) was obtained as colorless crystals; mp 78˚C (AcOEt-hexane); 1H NMR δ 7.83 (1H, dd, J
= 1, 3.8 Hz), 7.67 (1H, dd, J = 1, 5 Hz), 7.15 (1H, dd, J = 3.8, 5 Hz), 3.86 (2H, s), 3.77 (6H, s), 3.10 (2H,
13
d, J = 2.6 Hz), 2.04 (1H, t, J = 2.6 Hz); C NMR δ 189.5, 169.5, 143.4, 134.3, 132.6, 128.2, 79.1, 72.0,
54.6, 53.2, 41.3, 23.4; IR (KBr) 3263, 2958, 1741 cm-1; MS m/z 294 (M+); HRMS m/z calcd for
C14H14O5S (M+) 294.0561, found: 294.0553.
N-(2-Phenyl-2-oxoethyl)-N-2-propynyltosylamide (4i). To a mixture of 5 (0.816 g, 3.9 mmol), TBAI
(0.100 g, 0.27 mmol), and K2CO3 (0.663 g, 4.8 mmol) in DMF (30 mL) at rt was added a solution of 2-
bromoacetophenone 0.956 g, 4.8 mmol) in DMF (10 mL). After being stirred for 24 h, the reaction was
quenched with water. The mixture was extracted with ether. The organic extracts were washed with water
and brine, respectively, and dried. Evaporation of the solvent in vacuo gave a residue, which was purified
by column chromatography (hexane/AcOEt = 3 : 1) to furnish 4i (1.198 g, 93.8%) as pale yellow crystals;
1
mp 93-94˚C (AcOEt-hexane); H NMR δ 7.94 (2H, d, J = 7.3 Hz), 7.76, 7.31 (each 2H, d, J = 8.2 Hz),
7.60 (1H, t, J = 7.3 Hz), 7.47 (2H, t, J = 7.3 Hz), 4.81 (2H, s), 4.29 (2H, d, J = 2.4 Hz), 2.43 (3H, s), 2.12
13
(1H, t, J = 2.4 Hz); C NMR δ 193.2, 143.8, 136.0, 134.7, 133.8, 129.6, 128.8, 127.9, 127.5, 74.4, 51.4,
37.3, 21.5; IR (KBr) 3264, 2121, 1697 cm-1; MS m/z 327 (M+); HRMS m/z calcd for C18H17NO3S (M+)
327.0929, found: 327.0930.
Dimethyl 2-(2-phenyl-2-butenyl)-2-(2-propynyl)malonate (2c). A suspension of PPh3•EtBr (2.32 g, 6.3
mmol), and t-BuOK(0.673 g, 6.0 mmol) in THF (30 mL) was stirred at rt for 10 min. To this mixture was
added a solution of 4c (0.720 g, 2.5 mmol) in THF (10 mL). After being stirred for 1 h, the reaction was
quenched with water. The mixture was extracted with CHCl3. The usual work-up gave a residue, which
was purified by column chromatography (hexane/AcOEt = 10 : 1) to give 2c (0.643 g, 85.7%) as a pale
1
yellow oil; H NMR δ 7.10-7.33 (5H, m), 5.81 (0.72H, q, J = 6.9 Hz), 5.76 (0.28H, q, J = 7 Hz), 3.38
(0.56H, s), 3.52 (1.44H, s), 3.63 (4.32H, s), 3.21 (1.68H, s), 2.77 (1.44H, d, J = 2.6 Hz), 2.67 (0.56H, d, J
13
= 2.6 Hz), 2.03 (1H, t, J = 2.6 Hz), 1.88 (0.84H, d, J = 7 Hz), 1.88 (2.16H, d, J = 6.9 Hz); C NMR
δ 170.0, 169.9, 143.2, 138.8, 135.2, 130.4, 129.2, 127.9, 127.8, 127.6, 127.2, 126.7, 126.6, 79.8, 79.3,
71.5, 71.4, 56.8, 56.2, 52.3, 52.2, 30.9, 22.3, 22.1, 14.8, 14.7; IR (neat) 3273, 2955, 1733 cm-1; MS m/z
300 (M+); HRMS m/z calcd for C18H20O4 (M+) 300.1362, found: 300.1354.
General Procedure for Synthesis of Enynes (2d-f) from Ketones (4d-f). A suspension of PPh3•MeBr
(2.6 eq.), and t-BuOK (2.5 eq.) in THF (6 mL per 1 mmol of the ketone) was stirred at rt for 30 min. To
this mixture was added a solution of the ketone (1 eq.) in THF (5 mL per 1 mmol of the ketone). After

being stirred for 1 h, the reaction was quenched with water. The mixture was extracted with CHCl3. The
usual work-up gave a residue, which was purified by column chromatography (hexane/AcOEt = 10 : 1 ~
4 : 1) to give the corresponding exo-olefins (2c-f, i).
Dimethyl 2-[2-(3,4-methylenedioxyphenyl)-2-propenyl]-2-(2-propynyl)malonate (2d); from 4d (0.837
g, 2.52 mmol), 2d (0.788 g, 94.7%) was obtained as pale yellow crystals; mp 66-67˚C (hexane); 1H NMR
δ 6.78-6.83 (2H, m), 6.72 (1H, d, J = 8.6 Hz), 5.93 (2H, s), 5.24, 5.20 (each 1H, d, J = 1 Hz), 3.52 (6H, s),
13
3.27 (2H, s), 2.74 (2H, d, J = 2.6 Hz), 2.04 (1H, t, J = 2.6 Hz); C NMR δ 170.0, 147.5, 146.2, 143.3,
135.0, 120.3, 118.1, 107.8, 107.5, 101.1, 79.2, 71.8, 56.6, 52.5, 37.0, 22.4; IR (KBr) 3286, 2957, 1729
cm-1; MS m/z 330 (M+); HRMS m/z calcd for C18H18O6 (M+) 330.1101, found: 330.1093
Dimethyl 2-[2-(2-furyl-2-propenyl)]-2-(2-propynyl)malonate (2e); from 4e (0.743 g, 2.67 mmol), 2e
(0.648 g, 87.9%) was obtained as pale yellow crystals; mp 81-82˚C (hexane); 1H NMR δ 7.32 (1H, d, J =
1.5 Hz), 6.38 (1H, d, J = 3.3 Hz), 6.34 (1H, dd, J = 1.5, 3.3 Hz), 5.66 (1H, d, J = 1 Hz), 5.14 (1H, s), 3.66
(6H, s), 3.18 (2H, d, J = 1 Hz), 2.84 (2H, d, J = 2.6 Hz), 2.09 (1H, t, J = 2.6 Hz); 13C NMR δ 170.1, 154.0,
142.1, 131.9, 114.7, 111.1, 106.8, 79.4, 72.0, 57.1, 53.2, 34.6, 22.7; IR 3289, 2952, 1759, 1738 cm-1;
MS m/z 276 (M+); HRMS m/z calcd for C15H16O5 (M+) 276.0997, found: 276.0998.
Dimethyl 2-(2-propynyl)-2-[2-(2-thienyl-2-propenyl)]malonate (2f); from 4f (0.431 g, 1.47 mmol), 2f
1
(0.339 g, 78.9%) was obtained as pale yellow crystals; mp 73-74˚C (hexane); H NMR δ 7.14 (1H, dd, J
= 1, 5.2 Hz), 7.01 (1H, dd, J = 1, 3.6 Hz), 6.93 (1H, dd, J = 3.6, 5.2 Hz), 5.48, 5.17 (each 1H, s), 3.57 (6H,
s), 3.29 (2H, s), 2.83 (2H, d, J = 2.6 Hz), 2.08 (1H, t, J = 2.6 Hz); 13C NMR δ 170.0, 144.3, 136.5, 127.0,
124.8, 124.3, 117.1, 79.2, 71.9, 56.8, 52.6, 37.0, 22.6; IR (KBr) 3289, 3103, 2950, 1734 cm-1; MS m/z 292
(M+); HRMS m/z calcd for C15H16O4S (M+) 292.0768, found: 292.0759.
Dimethyl 2-(2-propynyl)-2-[2-(2-pyridyl-2-propenyl)]malonate (2g). To a stirred mixture of 1 (0.038 g,
0.23 mmol), 2-(2-pyridyl)propen-1-ol (0.021 g, 0.15 mmol) and Bu3P (0.051 g, 0.23 mmol) in benzene (1
mL) at 0˚C was added N, N, N’, N’-tetramethylazodicarboxamide (TMAD) (0.039 g, 0.23 mmol) in one
portion. After being stirred for 10 min, the reaction mixture was stirred at rt for 7 h. The precipitate was
filtered off and the filtrate was evaporated under reduced pressure to give a residue, which was purified
by column chromatography (Et2O/hexane = 8 : 1) to afford 2g (0.031 g, 72.2%) as colorless crystals; mp
47-48˚C (hexane); 1H NMR δ 8.53 (1H, d, J = 4.6 Hz), 7.63 (1H, dt, J = 1.7, 7.8 Hz), 7.44 (1H, d, J = 7.8
Hz), 7.11-7.18 (1H, m), 5.74 (1H, d, J = 1 Hz), 5.54 (1H, s), 3.54 (2H, s), 3.53 (6H, s), 2.78 (2H, d, J =
2.6 Hz), 2.06 (1H, t, J = 2.6 Hz); 13C NMR δ 170.2, 158.2, 148.4, 143.5, 136.4, 122.2, 121.0, 79.3, 71.7,
56.6, 52.4, 34.9, 22.7; IR (KBr) 3277, 2958, 1752, 1733 cm-1; MS m/z 286 (M+-1); HRMS m/z calcd for
C16H16NO4 (M+-1) 286.1077, found: 286.1066.
N-(2-Phenyl-2-propenyl)-N-2-propynyltosylamide (2h). To a mixture of 5 (0.326 g, 1.56 mmol) and
K2CO3 (0.261 g, 1.89 mmol) in DMF (18 mL) at 0˚C was added a solution of 3-iodo-2-phenylpropene

(0.460 g, 1.89 mmol) in DMF (5 mL). Then, the mixture was allowed to warm to rt and stirred for 2 h.
After cooling at 0˚C, the reaction was quenched with water. The mixture was extracted with ether. The
organic extracts were washed with water and brine, respectively, and dried. Evaporation of the solvent in
vacuo gave a residue, which was purified by column chromatography (hexane/AcOEt = 10 : 1) to furnish
2h (0.375 g, 74.0%) as pale yellow crystals; mp 60-61˚C (hexane); 1H NMR δ 7.74, 7.51 (each 2H, d, J =
8 Hz), 7.25-7.38 (5H, m), 5.57, 5.35 (each 1H, s), 4.27 (2H, s), 3.99 (2H, d, J = 2.3 Hz), 2.43 (3H, s), 1.97
(1H, t, J = 2.3 Hz); 13C NMR δ 143.7, 141.3, 137.6, 135.5, 129.4, 128.5, 128.2, 128.0, 126.4, 117.3, 74.1,
49.9, 35.5, 21.6; IR (KBr) 3270, 2119, 1596 cm-1; MS m/z 325 (M+); HRMS m/z calcd for C19H19NO2S
(M+) 325.1134, found: 325.1133.
N-(2-Phenyl-2-butenyl)-N-2-propynyltosylamide (2i). To a suspension of PPh3•EtBr (1.866 g, 5.0
mmol) in THF (25 mL) was added 1.58 M BuLi in THF (3.0 mL, 4.74 mmol) and the mixture was stirred
at rt for 10 min. To this mixture was added a solution of 4i (0.654 g, 2.0 mmol) in THF (5 mL). After
being stirred for 10 min, the reaction was quenched with water. The mixture was extracted with CHCl3.
The usual work-up gave a residue, which was purified by column chromatography (hexane/AcOEt = 10 :
1) to give 2i (0.513 g, 75.7%) as pale yellow crystals; mp 80-83˚C; 1H NMR δ 7.15-7.71 (9H, m), 6.04
(0.22H, q, J = 7.1 Hz), 5.76 (0.78H, q, J = 6.9 Hz), 4.35 (0.44H, s), 4.11 (1.56H, s), 4.00 (1.56H, s), 3.83
(0.44H, s), 2.38 (0.68H, s), 2.36 (2.32H, s), 2.01 (0.22H, t, J = 2 Hz), 1,86 (0.78H, d, J = 1.7 Hz), 1.85
(0.68H, d, J = 7.1 Hz), 1.63 (2.32H, d, J = 6.9 Hz); 13C NMR δ 143.3, 143.1, 139.8, 137.2, 135.7, 135.3,
134.6, 133.8, 129.7, 129.1, 128.4, 128.0, 127.9, 127.8, 127.5, 126.9, 126.3, 77.2, 76.7, 76.4, 73.7, 52.5,
43.2, 35.1, 34.8, 21.3, 21.2, 14.6, 14.1; IR (KBr) 3297, 2118, 1598 cm-1; MS m/z 339 (M+); HRMS m/z
calcd for C20H21NO2S (M+) 339.1291, found: 339.1285.
Dimethyl 2-(2-phenyl-2-propenyl)-2-(3-trimethylsilyl-2-propynyl)malonate (2j). To a suspension of
2a (0.069 g, 0.24 mmol) and CsF (0.001 g , 0.007 mmol) in THF (2 mL) at rt TMSCF3 (46 µL, 0.31
mmol) was added. After being stirred for 30 min, the mixture was filtered and the filtrate was evaporated
in vacuo to give a residue, which was purified by preparative TLC (hexane/AcOEt = 10 : 1) to afford 2i
(0.085 g, 98.6%) as a colorless oil; 1H NMR δ 6.93-7.05 (5H, m), 5.01 (1H, d, J = 1.7 Hz), 4.95 (1H, d, J
13
= 1.2 Hz), 3.13 (6H, s), 3.04 (2H, s), 2.48 (2H, s), -0.12 (9H, s); C NMR δ 169.9, 143.9, 140.9, 128.0,
127.5, 126.8, 118.8, 101.7, 88.5, 56.7, 52.3, 36.8, 23.5, -0.1; IR (neat) 2954, 2179, 1738, 1436 cm-1; MS
m/z 358 (M+); HRMS m/z calcd for C20H26O4Si (M+) 358.1600, found: 358.1661.
N-(2-Phenyl-2-propenyl)-N-(3-trimethylsilyl-2-propynyl)tosylamide (2k). To a suspension of 2h
(0.093 g, 0.29 mmol) and CsF (0.001 g , 0.007 mmol) in THF (6 mL) at rt TMSCF3 (55 µL, 0.37 mmol)
was added. After being stirred for 30 min, the mixture was filtered and the filtrate was evaporated in
vacuo to give a residue, which was purified by column chromatography (hexane/AcOEt = 10 : 1) to
afford 2k (0.109 g, 95.6%) as colorless crystals; mp 108-109˚C (hexane); 1H NMR δ 7.69, 7.49 (each 2H,

d, J = 8 Hz), 7.20-7.32 (5H, m), 5.52, 5.27 (each 1H, s), 4.20, 3.93 (each 2H, s), 2.36 (3H, s), -0.08 (9H,
s); 13C NMR δ 143.4, 141.1, 137.6, 135.5, 129.4, 129.3, 128.0, 127.8, 126.3, 117.2, 97.4, 91.3, 49.8, 36.4,
21.6, -0.5; IR (KBr) 3270, 2119, 1596 cm-1; MS m/z 397 (M+); HRMS m/z calcd for C22H27NO2SSi (M+)
397.1532, found: 397.1528.
General Procedures for Pauson-Khand Reaction of Enynes. A mixture of enyne (1 eq.) and Co2(CO)8
(1.2 eq.) in CH2Cl2 or toluene or 1,2-dichloroethane was stirred at rt for 1 h. Method A: NMO (3 eq.) was
added to the mixture three or four times at intervals of 15 min. Method B: The mixture in toluene was
refluxed. Method C: BuSMe (3.5 eq.) was added to the mixture and the resulting mixture was heated at
83˚C. The reaction mixture was diluted with ether and the precipitate was removed by suction filtration
through a Celite 545 short pad. After the solvent was removed in vacuo, purification of the residue
obtained by Methods A-C was carried out on preparative TLC (hexane/AcOEt = 8 : 5 ~ 3 : 2).
2,2-Dimethoxycarbonyl-5-oxo-3a-phenyl-3,3a,4,5-tetrahydro-1H-pentalene (6a); mp 137-138˚C
1
(AcOEt-hexane); H NMR δ 7.18-7.31 (3H, m), 7.09-7.16 (2H, m), 6.19 (d, 1H, J = 2 Hz), 3.73 (3H, s),
3.67 (1H, dd, J = 2, 18.1 Hz), 3.48 (1H, d, J = 13.7 Hz), 3.26 (3H, s), 3.15, 2.71 (each 1H, d, J = 18.1 Hz),
2.52 (1H, d, J = 18.1 Hz), 2.46 (1H, d, J = 13.7 Hz); 13C NMR δ 204.9, 181.3, 167.9, 166.8, 139.0, 125.0,
123.8, 123.6, 122.4, 56.5, 54.4, 49.8, 49.7, 49.2, 41.1, 31.2; IR (KBr) 2953, 1758, 1729, 1706, 1638 cm-1;
MS m/z 314 (M+); HRMS m/z calcd for C18H18O5 (M+) 314.1153, found: 314.1168.
2,2-Dimethoxycarbonyl-5-oxo-3a-(1-naphthyl)-3,3a,4,5-tetrahydro-1H-pentalene (6b); mp 125-
1
126˚C (AcOEt-hexane); H NMR δ 7.93 (1H, d, J = 8.3 Hz), 7.84-7.87 (1H, m), 7.71 (1H, d, J = 8.3 Hz),
7.48-7.60 (2H, m), 7.27 (1H, t, J = 8.3 Hz), 6.93 (1H, d, J = 6.9 Hz), 6.3 (1H, d, J = 1.8 Hz), 3.94 (1H,
dd, J = 1.8, 18.2 Hz), 3.70 (3H, s), 3.59 (1H, d, J = 13.2 Hz), 3.37 (1H, d, J = 18.2 Hz), 3.06 (1H, d, J =
13
17.2 Hz), 2.92 (3H, s), 2.92 (1H, d, J = 17.2 Hz), 2.66 (1H, d, J = 13.2 Hz); C NMR δ 207.7, 185.7,
171.4, 170.2, 139.7, 134.6, 130.2, 129.4, 128.4, 128.3, 126.1, 125.6, 125.0, 124.6, 124.5, 60.6, 57.6, 53.3,
53.2, 52.3, 45.9, 35.7; IR (KBr) 2650, 1732, 1704, 1638 cm-1; MS m/z 364 (M+); HRMS m/z calcd for
C22H20O5 (M+) 364.1293, found: 364.1321.
2,2-Dimethoxycarbonyl-4-methyl-5-oxo-3a-phenyl-3,3a,4,5-tetrahydro-1H-pentalene (6c); mp 94-
1
101˚C; H NMR δ 7.04-7.30 (5H, m), 6.24 (0.58H, s), 6.15 (0.42H, s), 3.74 (1.62H, s), 3.73 (1.38H, s),
3.51-3.77 (1.58H, m), 3.38 (1.62H, s), 3.31 (1.38H, s), 3.04-3.19 (1.42H, m), 2.39-2.86 (2H, m), 1.24
(1.38H, d, J = 7.9 Hz), 0.64 (1.62H, d, J = 7.3 Hz); 13C NMR δ 211.8, 210.7, 183.6, 182.9, 171.6, 170.5,
144.1, 138.4, 128.7, 128.3, 127.4, 127.2, 127.1, 126.3, 125.8, 125.7, 62.0, 61.6, 60.1, 59.6, 55.9, 55.1,
53.2, 52.8, 52.7, 44.5, 43.4, 39.3, 34.8, 34.4, 13.8, 11.7; IR (KBr) 2949, 1739, 1704, 1638 cm-1; MS m/z
328 (M+); HRMS m/z calcd for C19H20O5 (M+) 328.1311, found: 328.1319.
2,2-Dimethoxycarbonyl-5-oxo-3a-(3,4-methylenedioxyphenyl)-3,3a,4,5-tetrahydro-1H-pentalene
1
(6d); mp 145-147˚C (AcOEt-hexane); H NMR δ 6.68 (1H, d, J = 7.9 Hz), 6.64 (1H, d, J = 2 Hz), 6.55

(1H, dd, J = 2, 7.9 Hz), 6.16 (1H, d, J = 2 Hz), 5.93 (2H, s), 3.73 (3H, s), 3.65 (1H, dd, J = 2, 18.3 Hz),
3.48 (3H, s), 3.39 (1H, d, J = 13.5 Hz), 3.11 (1H, d, J = 18.3 Hz), 2.66, 2.47 (each 1H, d, J = 17.7 Hz),
13
2.43 (1H, d, J = 13.5 Hz); C NMR δ 208.5, 184.7, 171.4, 170.4, 148.1, 146.6, 136.3, 127.3, 119.5, 108.1,
106.6, 101.1, 60.0, 57.6, 53.4, 53.3, 52.9, 44.6, 34.7; IR (KBr) 2952, 1751, 1729, 1704, 1638 cm-1; MS
m/z 358 (M+); HRMS m/z calcd for C19H18O7 (M+) 358.1051, found: 358.1052.
2,2-Dimethoxycarbonyl-5-oxo-3a-(2-furyl)-3,3a,4,5-tetrahydro-1H-pentalene (6e); mp 115˚C
(AcOEt-hexane); 1H NMR δ 7.31 (1H, dd, J = 0.7, 2 Hz), 6.24 (1H, dd, J = 2, 3.3 Hz), 6.06 (1H, d, J = 2
Hz), 5.97 (1H, dd, J = 0.7, 3.3 Hz), 3.75, 3.66 (each 3H, s), 3.56 (1H, dd, J = 2, 17.8 Hz), 3.36 (1H, d, J
= 13.7 Hz), 3.19 (1H, d, J = 17.8 Hz), 2.63, 2.57 (each 1H, d, J = 17.5 Hz), 2.41 (1H, d, J = 13.7 Hz);
13C NMR δ 208.0, 182.5, 171.5, 170.6, 154.6, 142.4, 126.4, 110.3, 105.9, 60.3, 53.7, 53.3, 53.2, 50.1, 42.7,
34.8; IR (KBr) 2957, 1730, 1706, 1642 cm-1; MS m/z 304 (M+); HRMS m/z calcd for C16H16O6 (M+)
304.0946, found: 304.0954.
2,2-Dimethoxycarbonyl-5-oxo-3a-(2-thienyl)-3,3a,4,5-tetrahydro-1H-pentalene (6f); mp 125˚C
(AcOEt-hexane); 1H NMR δ 7.18 (1H, d, J = 4.8 Hz), 6.86 (1H, dd, J = 3.6, 4.8 Hz), 6.72 (1H, d, J = 3.6
Hz), 6.11 (1H, d, J = 2 Hz), 3.74 (3H, s), 3.72 (1H, dd, J = 2, 18.1 Hz), 3.56 (3H, s), 3.39 (1H, d, J =
13.7 Hz), 3.12 (1H, d, J = 18.1 Hz), 2.72, 2.63 (each 1H, d, J = 17.5 Hz), 2.58 (1H, d, J = 13.7 Hz); 13C
NMR δ 207.9, 184.0, 171.4, 170.5, 147.1, 126.8, 126.3, 125.0, 124.2, 60.3, 55.2, 53.6, 53.3, 53.1, 45.5,
34.5; IR (KBr) 2954, 1730, 1708, 1637 cm-1; MS m/z 320 (M+); HRMS m/z calcd for C16H16O5S (M+)
320.0708, found: 320.0707.
2,2-Dimethoxycarbonyl-5-oxo-3a-(2-pyridyl)-3,3a,4,5-tetrahydro-1H-pentalene (6g); mp 114-115˚C
(AcOEt-hexane); 1H NMR δ 8.47 (1H, d, J = 4 Hz), 7.62 (1H, dt, J = 2, 7.8 Hz), 7.11-7.17 (2H, m), 6.14
(1H, d, J = 2 Hz), 3.75 (3H, s), 3.72 (1H, d, J = 13.2 Hz), 3.59 (1H, dd, J = 2, 17.8 Hz), 3.57 (3H, s),
13
3.11 (1H, d, J = 17.8 Hz), 2.75, 2.67 (each 1H, d, J = 18 Hz), 2.51 (1H, d, J = 13.2 Hz); C NMR
δ 208.7, 185.1, 171.8, 171.0, 161.5, 148.8, 137.1, 126.9, 122.2, 120.2, 60.2, 60.1, 53.3, 53.0, 52.1, 43.2,
35.1; IR (KBr) 2950, 1752, 1727, 1705, 1636 cm-1; MS m/z 315 (M+); HRMS m/z calcd for C17H17NO5
(M+) 315.0114, found: 315.0115.
3a-Phenyl-2-tosyl-2,3,3a,4-tetrahydro-1H-cyclopenta[c]pyrrol-5-one (6h); mp 171-172˚C (AcOEt-
1
hexane); H NMR δ 7.57 (2H, d, J = 8.3 Hz), 7.19-7.27 (5H, m), 7.07-7.11 (2H, m), 6.17 (1H, s), 4.44
(1H, d, J = 9.7 Hz), 4.21, 4.14 (each 1H, d, J = 16.5 Hz), 3.13 (1H, d, J = 9.7 Hz), 2.58 (2H, s), 2.40 (3H,
13
s); C NMR δ 207.0, 178.9, 143.8, 141.2, 133.5, 129.8, 129.0, 127.4, 127.2, 127.1, 125.4, 57.8, 56.5,
50.4, 46.8, 21.5; IR (KBr) 1711, 1650 cm-1; EI MS m/z 353 (M+); HRMS m/z calcd for C20H19NO3S (M+)
353.1085, found: 353.1085.
4-Methyl-3a-phenyl-2-(toluene-4-sulfonyl)-2,3,3a,4-tetrahydro-1H-cyclopenta[c]pyrrol-5-one (6i);
1
mp 54-66˚C; H NMR δ 7.50-7.57 (2H, m), 7.15-7.27 (5H, m), 7.00-7.06 (2H, m), 6.27 (0.60H, s), 6.15

(0.40H, s), 4.55 (0.60H, d, J = 9.8 Hz), 4.19 (0.40H, d, J = 10.1 Hz), 4.18 (0.80H, s), 4.13 (1.20H, s),
3.17 (0.40H, d, J = 10.1 Hz), 3.09 (0.60H, d, J = 9.8 Hz), 2.83 (3H, s), 2.33 (1H, m), 1.13 (1.20H, d, J =
13
7.7 Hz), 0.65 (1.80H, d, J = 7.3 Hz); C NMR δ 210.5, 209.0, 177.4, 176.7, 143.7, 143.2, 133.6, 129.7,
129.0, 128.8, 127.5, 127.2, 127.1, 126.6, 126.5, 125.7, 125.1, 61.0, 60.2, 57.6, 53.6, 53.2, 53.0, 47.2, 46.7,
21.5, 13.9, 11.3; IR (KBr) 2921, 1717, 1655 cm-1; EI MS m/z 367 (M+); HRMS m/z calcd for C21H21NO3S
(M+) 367.1240, found: 367.1242.
5,5-Dimethoxycarbonyl-7a-methyl-1,4,5,6,7,7a-hexahydroinden-2-one (10); mp 75-76˚C (AcOEt-
1
hexane); H NMR δ 5.89 (1H, d, J = 2 Hz), 3.77, 3.72 (each 3H, s), 3.35 (1H, dd, J = 2.3 Hz, 13.9 Hz),
2.86 (1H, dd, J = 1.7, 13.9 Hz), 2.36-2.43 (1H, m), 2.31, 2.20 (each 1H, d, J = 18.8 Hz), 2.08 (1H, dt, J =
13
4 , 14 Hz), 1.88-1.96 (1H, m), 1.58 (1H, dt, J = 4, 14 Hz), 1.29 (3H, s); C NMR δ 182.0, 171.7, 170.7,
129.2, 57.1, 53.1, 52.8, 51.6, 42.1, 36.6, 32.1, 27.5, 24.0; IR (KBr) 2962, 1737, 1698 cm-1; MS m/z 266
(M+); HRMS m/z calcd for C14H18O5 (M+) 266.1154, found: 266.1153.
6,6-Dimethoxycarbonyl-7a-methyl-1,4,5,6,7,7a-hexahydroinden-2-one (15); mp 68-70˚C (AcOEt-
hexane); 1H NMR δ 5.84 (1H, d, J = 1.7 Hz), 3.80, 3.72 (each 3H, s), 2.66-2.88 (3H, m), 2.81 (1H, d, J =
13
13.9 Hz), 2.29 (2H, s), 2.09 (1H, d, J = 13.9 Hz), 1.56-1.68 (1H, m), 1.11 (3H, s); C NMR δ 183.0,
171.2, 170.0, 127.1, 53.1, 52.9, 52.7, 43.5, 42.3, 32.3, 25.0, 24.6; IR (KBr) 2954, 1730, 1711, 1686, 1625
cm-1; MS m/z 266 (M+); HRMS m/z calcd for C14H18O5 (M+) 266.1154, found: 266.1158.
5,5-Dimethoxycarbonyl-1-phenyl-1,4,5,6,7,7a-hexahydroinden-2-one (17); mp 85-86˚C (AcOEt-
hexane); 1H NMR δ 7.21-7.33 (3H, m), 7.08-7.11 (2H, m), 6.07 (1H, s), 3.75, 3.74 (each 3H, s), 3.56 (1H,
dd, J = 2.2, 14.3 Hz), 3.12 (1H, d, J = 2.9 Hz), 2.73 (1H, d, J = 14.3 Hz), 2.67-2.78 (1H, m), 2.53 (1H, dq,
13
J = 2.6, 13.8 Hz), 2.22-2.32 (1H, m), 1.91 (1H, dt, J = 13.8, 3.7 Hz) 1.43 (1H, dq, J = 13.1, 3 Hz); C
NMR δ 207.2, 177.0, 171.2, 170.0, 138.7, 128.9, 128.8, 127.9, 127.0, 59.6, 56.4, 53.1, 52.8, 50.5, 35.4,
30.6, 29.8; IR (KBr) 3275, 2955, 1734 cm-1; MS m/z 328 (M+); HRMS m/z calcd for C19H20O5 (M+)
328.1309, found: 328.1319.
1
6,6-Dimethoxycarbonyl-1-phenyl-1,4,5,6,7,7a-hexahydroinden-2-one (19); oil; H NMR δ 7.21-7.36
(3H, m), 7.09-7.15 (2H, m), 5.99 (1H, s), 3.73, 3.72 (each 3H, s), 3.16 (1H, d, J = 2.6 Hz), 2.84-2.97 (3H,
m), 2.62-2.72 (1H, m), 2.55 (1H, dd, J = 5, 14.1 Hz), 1.89 (1H, dt, J = 4.7, 13 Hz), 1.74 (1H, t, J = 9.7
Hz); 13C NMR δ 207.0, 179.3, 171.3, 170.5, 138.3, 128.8, 128.0, 127.1, 126.9, 59.8, 54.7, 53.0, 52.9, 47.3,
37.9, 31.2, 27.1; IR (neat) 2954, 1732, 1705, 1629 cm-1; MS m/z 328 (M+); HRMS m/z calcd for C19H20O5
(M+) 328.1309, found: 328.1310.
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