Palladium-catalyzed divergent reactions of 1,6-enyne carbonates: Synthesis of vinylidenepyridines and vinylidenepyrrolidines

Article abstract of DOI:10.1021/jo202590w

A method for preparing five- or six-membered heterocyclic compounds from enyne carbonates via palladium catalysis was developed. Enyne carbonates were transformed into 3-vinylidene-1-tosylpyridines 2 in the presence of PdI ₂ as the catalyst. Us

Full text of DOI:10.1021/jo202590w

Article
pubs.acs.org/joc
Palladium-Catalyzed Divergent Reactions of 1,6-Enyne Carbonates:
Synthesis of Vinylidenepyridines and Vinylidenepyrrolidines
Shu-Chun Zhao, Ke-Gong Ji, Lei Lu, Ting He, An-Xi Zhou, Ru-Long Yan, Shaukat Ali, Xue-Yuan, Liu,
and Yong-Min Liang*
State Key Laboratory of Applied Organic Chemistry, Lanzhou University, and State Key Laboratory of Solid Lubrication, Lanzhou
Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000, P.R. China
S
* Supporting Information
ABSTRACT: A method for preparing five- or six-membered
heterocyclic compounds from enyne carbonates via palladium
catalysis was developed. Enyne carbonates were transformed
into 3-vinylidene-1-tosylpyridines 2 in the presence of PdI2 as
the catalyst. Using Pd(dba)2 as the catalyst, 3-vinylidene-1-
tosylpyrrolidines 3 were obtained. Further functionalizations of
compounds 3 were carried out in a one-pot manner.
Scheme 1. Design of the Proposed Palladium-Catalyzed
Process
INTRODUCTION
■
The construction of carbon−carbon and carbon−heteroatom
bonds via palladium catalysis from propargylic compounds with
nucleophiles has developed tremendously over the past few
years.1 Since the first report of Tsuji in 1985, many interesting
reactions in this family have been shown to be very effective for
organic synthesis,2 including the efforts of our group.3 Olefins
as nucleophiles are well-known to react with allenylpalladium to
form carbon−carbon bonds.4 However, much less attention has
been paid to the propargylic substitution reactions of
propargylic carbonates with olefins as nucleophiles via
palladium catalysis because most of these reactions give rise
to corresponding allenic systems and subsequent rearranged
derivatives.5 Thus, allenes that can be prepared by isomer-
ization, metal-mediated reactions, transition-metal-catalyzed
reactions, and other reactions6 continue to attract considerable
attention due to their extraordinary properties, such as strained
structure and high reactivity.7
Very recently, our group has reported a concise synthesis of
five-membered allenes 3 from hydroxylated enynes using
Brønsted acids as catalysts.8 This synthesis was performed in
the context of our ongoing efforts to construct various
functionalized heterocyclic structures, as well as to form
carbon−carbon and carbon−heteroatom bonds from prop-
argylic compounds with nucleophiles using palladium as the
catalyst. The vision was that 1,6-enyne carbonates would first
generate an intermediate allenylpalladium A by facile
decarboxylation, which would be subsequently trapped by an
olefin in an intramolecular fashion to form the putative
products (Scheme 1).9
RESULTS AND DISCUSSION
■
To explore the proposed intramolecular cyclization reaction, a
model enyne carbonate 1a was treated with 5 mol % Pd(OAc)2,
20 mol % PPh3, 2 equiv of KI, and 2 equiv of Et3N in DMF as
the solvent under oxygen. After the mixture was stirred at 80 °C
for 2 h, only a 20% yield of 2a and trace amounts of 3a were
isolated (Table 1, entry 1). Further investigation revealed that a
larger catalyst loading and higher reaction temperature gave a
higher yield of 2a (entries 2, 4, and 5). When a monodentate
phosphine ligand such as P(2-furyl)3 was used, a moderate yield
of 2a was obtained (entry 3). When PdI2 was used as the
catalyst, 2a was the sole product (entry 6).
Other bases were screened (entries 7 and 8), but Et3N was
proven to be the best. The influences of the reaction additive
and solvent were also screened (entries 9−11). The
combination of DMF and TBHP was found to give the best
result (entry 10). The cyclization of a six-membered ring gave a
low yield without an additive, revealing that the additive played
an important role in this reaction system. The reason may be
the formation of I3− upon the addition of KI or TBHP. I3− had
a spatial interaction with the palladium catalyst; thus, less
catalyst was available for the formation of intermediate B (in
In the current study, a novel strategy for the construction of
heterocyclic allenes from 1,6-enyne carbonates 1 using
palladium as the catalyst is reported. Not only 3-vinylidene-1-
tosylpyridines but also 3-vinylidene-1-tosylpyrrolidines were
obtained in moderate to good yields.
Received: December 20, 2011
Published: February 27, 2012
© 2012 American Chemical Society
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a
Table 1. Palladium-Catalyzed Synthesis of Heterocyclic Allenes from 1,6-Enyne Carbonate 1a
Yield (%)
catalyst
base
T
additive
(equiv)
entry
(mol %)
(equiv)
ligand (mol %)
solvent
(°C)
2a
20
3a
b
1
Pd(OAc)2 (5)
Pd(OAc)2 (10)
Pd(OAc)2 (10)
Pd(OAc)2 (10)
Pd(OAc)2 (10)
PdI2 (10)
Et3N (2)
Et3N (2)
Et3N (2)
Et3N (2)
Et3N (2)
Et3N (2)
KOH (2)
KOAc (2))
Et3N (2)
Et3N (2)
Et3N (2)
KOAc (2)
KOAc (2)
KOAc (2)
KOAc (2)
KOAc (2)
KOAc (2)
KOAc (2)
Et3N (2)
KOH (2)
PPh3 (20)
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMSO
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
80
80
80
85
95
85
85
85
85
85
85
80
80
80
80
80
85
90
85
85
KI (2)
trace
trace
trace
14
b
b
b
b
b
b
b
2
PPh3 (40)
KI (2)
KI (2)
KI (2)
KI (2)
KI (2)
KI (2)
KI (2)
41
48
60
50
54
10
45
59
75
40
trace
trace
12
−
3
P(2-furyl)3 (40)
P(2-furyl)3 (40)
P(2-furyl)3 (40)
P(2-furyl)3 (40)
P(2-furyl)3 (40)
P(2-furyl)3 (40)
P(2-furyl)3 (40)
P(2-furyl)3 (40)
P(2-furyl)3 (40)
PPh3 (20)
4
5
trace
−
−
−
−
−
−
13
6
7
PdI2(10)
8
PdI2 (10)
cd
,
9
PdI2 (10)
TBHP (2)
c
10
11
12
13
14
15
16
17
18
19
20
PdI2 (10)
TBHP (2)
c
PdI2 (10)
−
−
−
−
−
−
−
−
c
Pd(OAc)2 (5)
Pd(OAc)2 (5)
Pd(OAc)2 (5)
Pd2(dba)3 (5)
Pd(dba)2 (10)
Pd(dba)2 (10)
Pd(dba)2 (10)
Pd(dba)2 (10)
Pd(dba)2 (10)
c
P(o-tolyl)3 (20)
P(2-furyl)3 (10)
P(2-furyl)3 (10)
P(2-furyl)3 (10)
P(2-furyl)3 (10)
P(2-furyl)3 (10)
P(2-furyl)3 (10)
P(2-furyl)3 (10)
47
c
70
c
57
c
−
−
−
−
80
c
97
78
c
c
−
−
52
c
−
55
a
Unless otherwise specified, the reaction was carried out by using 1a (0.20 mmol), Pd catalysts (10 mol %), and bases in solvent (2 mL) for 2 h.
Under oxygen. Under an argon atmosphere. TBHP = tert-butyl hydroperoxide.
b
c
d
Scheme 3), which selectively favored a six-membered ring
formation. Ultimately, the use of 10 mol % PdI2, 40 mol % P(2-
furyl)3, 2 equiv of Et3N, and 2 equiv of TBHP in DMF at 85 °C
under an argon atmosphere was found to be the most efficient
and used as the standard conditions for 2a.
product (e.g., 2n in 53% yield and 2o in 57% yield). The
substrate scope can also be extended to vinyl enyne carbonates,
such as 1q. Substrates with a hydrogen atom and aliphatic
substitution under the standard reaction conditions were also
investigated, and the corresponding products were obtained in
49%, 31%, and 70% yields. However, some oxygenated enyne
carbonates such as 1t and amines such as 1u cannot afford the
desired products.
Without using the additive TBHP, only trace amounts of 2a
and a 13% yield of 3a (entry 12) were obtained when 1a was
treated with Pd(OAc)2 in the presence of 2 equiv of KOAc and
PPh3 (20 mol %) in DMF as the solvent, and when the mixture
was stirred at 80 °C for 2 h under an argon atmosphere. The
use of phosphine ligand P(2-furyl)3 gave a higher yield of 3a
(entries 13 and 14). Pd2(dba)3 and Pd(dba)2, as convenient
sources of palladium(0), were found to be effective for
selectively generating 3a (entries 15 and 16). With increased
temperature to 85 °C, the desired product 3a was obtained in
the highest yield (entries 17 and 18). Compared with KOAc, an
organic base such as Et3N and a stronger inorganic base such as
KOH were less effective (entries 19 and 20). Thus, the
optimized reaction conditions for 3a were Pd(dba)2 (10 mol
%), P(2-furyl)3 (10 mol %), KOAc (2 equiv), and DMF (2 mL)
at 85 °C.
Under the optimized conditions, various representative
enyne carbonates 1a−1u were then subjected to the optimized
conditions selected for 2a, as shown in Table 2. The reaction
was found to tolerate a variety of functional groups at the
ortho-, meta-, and para-positions of the phenyl moiety in
substituted enyne carbonates, indicating that the steric effect
has little impact on this transformation. The substrates with a 2-
naphthyl or a heterocyclic ring can also afford the desired
Subsequently, the scope of 3-vinylidene-1-tosylpyrrolidines 3
was examined. Under the optimized conditions for 3a, a wide
range of 1,6-enyne carbonates 1a−1u in the presence of 10 mol
% Pd(dba)2 at 85 °C in DMF was also investigated. The
substrates 1a−o and 1s were found to be effectively converted
into the corresponding five-member heterocyclic allenes 3 in
moderate to good yields, as shown in Table 2. Enyne
carbonates with a heterocyclic ring, such as the thiophene
nucleus, can also afford the desired product (e.g., 3o in 40%
yield). The substrates with aliphatic R1 and R2 groups can also
afford the desired product (e.g., 3s in 45% yield). The results
revealed that electron-donating groups favored product
formation (1f−1m), whereas electron-withdrawing groups
(e.g., Cl and Br) hindered product formation (1b−1e).
To develop a method for a one-pot cyclization/Suzuki
coupling,10 aryl boronic acids were added to the reaction
mixture under the optimized conditions selected for 3a. The
Suzuki coupling products 3aa and 3ab, highly functionalized 3-
vinylidene-1-tosylpyrrolidines, were obtained in moderate
yields (Scheme 2).
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Based on the above observations, the following plausible
mechanisms for palladium-catalyzed intramolecular cyclization
reactions (Scheme 3) are proposed. PdI2 is initially reduced to
Pd(0) by a ligand, and both routes 1 and 2 are catalyzed by
Pd(0) via the following steps: (a) The Pd(0)-catalyzed
transformation of 1,6-enyne carbonates generates allenylpalla-
dium intermediate A or C, which is readily attacked by an olefin
Table 2. PdI2-Catalyzed Synthesis of 3-Vinylidene-1-
tosylpyridines 2 and Pd(dba)2-Catalyzed Synthesis of 3-
Vinylidene-1-tosylpyrrolidines 3 from 1,6-Enyne Carbonates
1
nucleophile to form intermediate B or D.11 I3 may have a
−
strong spatial interaction with the palladium catalyst and
induces more hindered catalysts to form five-membered ring B,
which selectively favors six-membered ring formation D. The
stability of the formation of intermediates D and B determines
the regioselective insertion of olefin into the C−Pd bond in the
allenylpalladium intermediate to form five- or six-membered
rings. (b) The β-hydrogen elimination3h of intermediate D or B
would give six-membered heterocyclic allenes 2 or five-
membered heterocyclic allenes 3.
CONCLUSION
■
In summary, Pd-catalyzed divergent cyclizations of 1,6-enyne
carbonates were developed. The cyclizations provide a versatile
cascade reaction for the synthesis of heterocyclic allenes. The
method can be combined with Suzuki coupling to prepare
highly functionalized 3-vinylidene-1-tosylpyrrolidines in a one-
pot manner.
EXPERIMENTAL SECTION
■
Typical Procedure for the Preparation of Enyne Carbonates
1a−1u. Method A.12 To a stirred solution of the appropriate
terminal alkyne A (1.2 equiv) in THF (1.0 M) was added ethyl
magnesium bromide (1.0 M in THF, 1.1 equiv) at room
temperature. The resulting solution was stirred at 50 °C for 1 h.
Then B (1.0 equiv) in THF (0.35 M) was added slowly by
syringe to the resulting solution at room temperature and
stirred for 3 h. The reaction mixture was quenched by addition
of saturated aqueous ammonium chloride (40 mL) and
extracted with ethyl ether (2 × 40 mL). The combined organic
layers were washed with brine, dried over Na2SO4, and
concentrated under reduced pressure. The crude material was
purified by flash column chromatography to obtain the pure
propargylic alcohols C in quantitative yield.
To a mixture of propargylic alcohol C (2.37 mmol) and pydrine (19
mmol) in methylene chloride (30 mL) was added methyl
chloroformate (7.11 mmol) at 0 °C. The reaction mixture was stirred
at 0 °C for 2.5 h. The reaction mixture was quenched by addition of
saturated aqueous ammonium chloride and extracted with ethyl ether.
The combined organic layers were washed with water and brine and
dried over Na2SO4, and the solvent was removed under reduced
pressure. The concentrate was purified by flash column chromatog-
raphy to obtain the desired propargylic esters 1.
a
Condition A: The reaction was carried out by using 1 (0.2 mmol),
PdI2 (10 mol %), P(2-furyl)3 (40 mol %), Et3N (2 equiv), and TBHP
Method B.13 To a solution of A (22 mmol) in THF (100 mL) was
added n-BuLi (2.2 M in hexane, 10.9 mL, 24 mmol) at −20 °C, and
the mixture was stirred at the same temperature for 5 min. To this
solution was added ketone or aldehyde (20 mmol) in a dropwise
manner, and the mixture was then stirred at −20 °C for 30 min. To
this solution was slowly added methyl chloroformate (3.9 mL, 50
(2 equiv) in DMF (2 mL) at 85 °C under an argon atmosphere.
b
Condition B: The reaction was carried out by using 1 (0.2 mmol),
Pd(dba)2 (10 mol %), P(2-furyl)3 (10 mol %), and KOAc (2 equiv) in
c
DMF (2 mL) at 85 °C under an argon atmosphere. Decomposed.
d
No gain.
Scheme 2. One-Pot Cyclization/Suzuki Coupling of 1,6-Enyne 1a with Aryl Boronic Acids 4
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Scheme 3. Proposed Mechanism
154.4, 143.4, 139.2, 137.7, 135.7, 134.4, 129.8, 129.5, 129.3, 127.7,
127.5, 125.5, 117.7, 82.1, 80.6, 68.3, 55.1, 44.1, 35.6, 25.8, 21.4, 17.6;
IR (neat, cm−1) 3398, 2923, 2359, 1753, 1440, 1260. Anal. Calcd for
C24H26ClNO5S: C, 60.56; H, 5.51; N, 2.94. Found: C, 60.58; H, 5.48;
N, 2.93.
1d: Compound 1d was prepared according to method A. 1H NMR
(400 MHz, CDCl3): δ 7.72−7.69 (d, J = 8.4 Hz, 2H), 7.37−7.35 (m,
2H), 7.30−7.19 (m, 4H), 6.35 (s, 1H), 5.10−5.06 (t, J = 7.2 Hz, 1H),
4.22−4.11 (m, 2H), 3.83−3.71 (m, 2H), 3.81 (s, 3H), 2.34 (s, 3H),
1.68 (s, 3H), 1.54 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 154.2,
143.3, 138.9, 135.6, 133.3, 132.8, 130.3, 129.4, 129.3, 128.8, 127.5,
126.9, 117.6, 81.6, 80.2, 65.9, 55.0, 43.9, 35.5, 25.6, 21.2, 17.4; IR
(neat, cm−1) 3396, 2922, 2359, 1754, 1441, 1256. Anal. Calcd for
C24H26ClNO5S: C, 60.56; H, 5.51; N, 2.94. Found: C, 60.55; H, 5.53;
N, 2.94.
mmol), and the mixture was warmed up to 0 °C and stirred at the
same temperature for 2 h. The reaction was quenched with a saturated
solution of ammonium chloride and extracted with ether (3 × 60 mL).
The combined organic layer was washed with brine (2 × 10 mL) and
dried over anhydrous sodium sulfate. The solvent was removed under
vacuum, and the concentrate was purified by flash column
chromatography to obtain 1r−s.
1
1e: Compound 1e was prepared according to method A. H NMR
(400 MHz, CDCl3): δ 7.71−7.69 (d, J = 8.4 Hz, 2H), 7.46−7.44 (d, J
= 8.4 Hz, 2H), 7.22−7.19 (d, J = 8.0 Hz, 2H), 7.13−7.10 (d, J = 8.4
Hz, 2H), 5.95 (s, 1H), 5.11−5.06 (m, 1H), 4.23−4.11 (m, 2H), 3.82−
3.69 (m, 2H), 3.79 (s, 3H), 2.36 (s, 3H), 1.69 (s, 3H), 1.56 (s, 3H);
13C NMR (100 MHz, CDCl3) δ 154.5, 143.4, 139.1, 135.8, 134.9,
131.7, 129.4, 129.1, 127.7, 123.4, 117.7, 82.1, 80.7, 68.5, 55.1, 44.1,
35.6, 25.8, 21.5, 17.7; IR (neat, cm−1) 3396, 2957, 2923, 2359, 1752,
1257, 1161. Anal. Calcd for C24H26BrNO5S: C, 55.39; H, 5.04; N,
2.69. Found: C, 55.37; H, 5.05; N, 2.68.
Characterization Data of Enyne Carbonates 1a−1u. 1a:
1
Compound 1a was prepared according to method A. H NMR (400
MHz, CDCl3): δ 7.71−7.69 (d, J = 8.0 Hz, 2H), 7.37−7.30 (m, 3H),
7.23−7.25 (m, 2H), 7.20−7.18 (m, J = 8.0 Hz, 2H), 5.60 (s, 1H),
5.11−5.07 (t, J = 7.2 Hz, 1H), 4.23−4.11 (m, 2H), 3.83−3.70 (m,
2H), 3.79 (s, 3H), 2.34 (s, 3H), 1.69 (s, 3H), 1.55 (s, 3H); 13C NMR
(100 MHz, CDCl3) δ 154.6, 143.4, 139.1, 135.8, 135.7, 129.4, 129.1,
128.5, 127.6, 127.4, 117.7, 81.5, 81.2, 69.2, 54.9, 44.0, 35.6, 25.7, 21.4,
17.6; IR (neat, cm−1) 3399, 2922, 2868, 1751, 1597, 1441, 1346, 1258,
1161. Anal. Calcd for C24H27NO5S: C, 65.28; H, 6.16; N, 3.17. Found:
C, 65.30; H, 6.18; N, 3.13.
1
1f: Compound 1f was prepared according to method A. H NMR
(400 MHz, CDCl3): δ 7.71−7.69 (d, J = 8.4 Hz, 2H), 7.20−7.18 (m,
3H), 7.13 (s, 3H), 5.95 (s, 1H), 5.11−5.07 (t, J = 7.2 Hz, 1H), 4.23−
4.10 (m, 2H), 3.80−3.73 (m, 2H), 3.78 (s, 3H), 2.35 (s, 3H), 2.34 (s,
3H), 1.69 (s, 3H), 1.56 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
154.7, 143.3, 139.1, 139.0, 135.8, 132.9, 129.4, 129.2, 127.7, 127.4,
117.8, 81.4, 81.3, 69.1, 54.9, 44.0, 35.7, 25.8, 21.4, 21.2, 17.7; IR (neat,
cm−1) 3410, 2922, 2851, 1749, 1383, 1257. Anal. Calcd for
C25H29NO5S: C, 65.91; H, 6.42; N, 3.07. Found: C, 65.93; H, 6.41;
N, 3.05.
1
1b: Compound 1b was prepared according to the method A. H
NMR (400 MHz, CDCl3): δ 7.71−7.69 (d, J = 8.0 Hz, 2H), 7.30−7.27
(m, 2H), 7.22−7.17 (m, 4H), 5.97 (s, 1H), 5.10−5.06 (m, 1H), 4.22−
4.11 (m, 2H), 3.82−3.70 (m, 2H), 3.78 (s, 3H), 2.35 (s, 3H), 1.69 (s,
3H), 1.56 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 154.4, 143.4,
139.0, 135.8, 135.0, 134.4, 129.3, 128.7, 128.6, 127.6, 117.6, 81.9, 80.7,
68.3, 54.9, 44.0, 35.5, 25.7, 21.3, 17.6; IR (neat, cm−1) 3395, 2922,
2359, 1751, 1383. Anal. Calcd for C24H26ClNO5S: C, 60.56; H, 5.51;
N, 2.94. Found: C, 60.51; H, 5.49; N, 2.99.
1
1g: Compound 1g was prepared according to method A. H NMR
1
(400 MHz, CDCl3): δ 7.72−7.69 (d, J = 8.4 Hz, 2H), 7.23−7.03 (m,
6H), 5.95 (s, 1H), 5.11−5.07 (m, 1H), 4.23−3.10 (m, 2H), 3.82−3.70
(m, 2H), 3.78 (s, 3H), 2.34 (s, 3H), 2.33 (s, 3H), 1.69 (s, 3H), 1.56 (s,
3H); 13C NMR (100 MHz, CDCl3) δ 154.6, 143.3, 139.0, 138.3,
135.7, 129.9, 129.4, 128.4, 128.0, 127.6, 124.4, 117.8, 81.4, 81.3, 69.2,
1c: Compound 1c was prepared according to method A. H NMR
(400 MHz, CDCl3): δ 7.72−7.69 (d, J = 8.0 Hz, 2H), 7.35−7.31 (m,
1H), 7.28−7.14 (m, 4H), 7.13−7.12 (m, 1H), 5.95 (s, 1H), 5.11−5.06
(m, 1H), 4.23−4.10 (m, 2H), 3.83−3.69 (m, 2H), 3.82 (s, 3H), 2.35
(s, 3H), 1.70 (s, 3H), 1.55 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
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54.9, 44.0, 35.7, 25.7, 21.4, 21.2, 17.6; IR (neat, cm−1) 3403, 2922,
2851, 1751, 1597, 1346, 1259. Anal. Calcd for C25H29NO5S: C, 65.91;
H, 6.42; N, 3.07. Found: C, 65.90; H, 6.44; N, 3.06.
1258. Anal. Calcd for C28H29NO5S: C, 68.41; H, 5.95; N, 2.85. Found:
C, 68.43; H, 5.93; N, 2.84.
1o: Compound 1o was prepared according to method A. 1H NMR
(400 MHz, CDCl3): δ 7.72−7.69 (d, J = 8.0 Hz, 2H), 7.33−7.31 (m,
1H), 7.26−7.18 (m, 2H), 7.01−7.00 (d, J = 3.6 Hz, 1H), 6.95−6.92
(m, 1H), 6.22 (s, 1H), 5.14−5.10 (m, 1H), 4.23−4.11 (m, 2H), 3.86−
3.75 (m, 5H), 2.34 (s, 3H), 1.72 (s, 3H), 1.62 (s, 3H); 13C NMR (100
MHz, CDCl3) δ 154.5, 143.5, 139.3, 138.5, 135.8, 129.5, 127.9, 127.7,
127.4, 126.6, 117.8, 81.2, 80.6, 64.2, 55.1, 44.2, 35.6, 25.8, 21.5, 17.8;
IR (neat, cm−1) 3397, 2922, 1749, 1381, 1258, 1159. Anal. Calcd for
C22H25NO5S2: C, 59.04; H, 5.63; N, 3.13. Found: C, 59.02; H,5.65; N,
3.13.
1
1h: Compound 1h was prepared according to the method A. H
NMR (400 MHz, CDCl3): δ 7.70−7.68 (d, J = 8.4 Hz, 2H), 7.26−7.12
(m, 6H), 6.15 (s, 1H), 5.10−5.05 (t, J = 7.2 Hz, 1H), 4.22−4.10 (m,
2H), 3.81−3.69 (m, 2H), 3.79 (s, 3H), 2.34 (s, 3H), 2.28 (s, 3H), 1.68
(s, 3H), 1.53 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 154.5, 143.3,
138.9, 135.8, 133.9, 130.6, 129.3, 129.0, 127.6, 127.5, 126.1, 117.7,
81.4, 81.0, 67.1, 54.9, 43.9, 35.6, 25.7, 21.3, 15.7, 17.5; IR (neat, cm−1)
3405, 2923, 2359, 1751, 1598, 1346, 1258. Anal. Calcd for
C25H29NO5S: C, 65.91; H, 6.42; N, 3.07. Found: C, 65.89; H, 6.42;
N, 3.08.
1p: Compound 1p was prepared according to method A. 1H NMR
(400 MHz, CDCl3): δ 7.73−7.71 (d, J = 8.0 Hz, 2H), 7.31−7.28 (m,
2H), 5.12−5.08 (m, 1H), 4.96−4.92 (t, J = 6.6 Hz, 1H), 4.12−4.11 (d,
J = 1.6 Hz, 2H), 3.79−3.77 (m, 5H), 2.43 (s, 3H), 1.72 (s, 3H), 1.65
(s, 3H), 1.58−1.40 (m, 2H), 1.30−1.21 (m, 2H), 0.89−0.85 (t, J = 7.4
Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 154.8, 143.3, 138.9, 136.0,
129.4, 127.6, 117.8, 82.1, 79.4, 67.5, 54.8, 43.9, 36.4, 35.5, 25.8, 21.4,
18.0, 17.7, 13.4; IR (neat, cm−1) 3398, 2961, 1751, 1382, 1348, 1266,
1161. Anal. Calcd for C21H29NO5S: C, 61.89; H, 7.17; N, 3.44. Found:
C, 61.87; H,7.18; N, 3.43.
1
1i: Compound 1i was prepared according to method A. H NMR
(400 MHz, CDCl3): δ 7.72−7.69 (d, J = 8.4 Hz, 2 H), 7.20−7.17 (d, J
= 8.4 Hz, 2H), 7.09−7.04 (m, 2H), 6.99−6.96 (m, 1H), 5.92 (s, 1H),
5.11−5.07 (m, 1H), 4.23−4.10 (m, 2H), 3.82−3.70 (m, 2H), 3.78 (s,
3 H), 2.34 (s, 3H), 2.26 (s, 3H), 2.24 (s, 3H), 1.69 (s, 3H), 1.56 (s,
3H); 13C NMR (100 MHz, CDCl3) δ 154.7, 143.3, 139.1, 137.8,
136.8, 135.7, 133.3, 129.7, 129.4, 128.6, 127.7, 124.9, 117.8, 81.5, 81.2,
69.2, 54.9, 44.0, 35.7, 25.8, 21.4, 19.7, 19.6, 17.6; IR (neat, cm−1) 3395,
2922, 1750, 1597, 1257. Anal. Calcd for C26H31NO5S: C, 66.50; H,
6.65; N, 2.98. Found: C, 66.49; H, 6.63; N, 3.01.
1q: Compound 1q was prepared according to method A. 1H NMR
(400 MHz, CDCl3): δ 7.75−7.69 (m, 2H), 7.39−7.29 (m, 5H), 7.26−
7.20 (m, 2H), 6.62 −6.58(d, J = 7.6 Hz, 1H), 6.03−5.96 (m, 1H),
5.63−5.61 (m, 1H), 5.14−5.10 (t, J = 7.2 Hz, 1H), 4.18−4.14 (m,
2H), 3.83−3.74 (m, 5H), 2.30 (s, 3H), 1.72 (s, 3H), 1.65 (s, 3H); 13C
NMR (100 MHz, CDCl3) δ 154.6, 143.5, 139.2, 135.8, 135.3, 134.9,
129.5, 129.3, 128.8, 128.7, 127.8, 127.7, 127.0, 126.9, 122.6, 117.8,
81.5, 80.3, 67.9, 55.0, 44.1, 35.7, 25.8, 21.4, 17.8; IR (neat, cm−1) 3493,
3029, 2959, 2925, 1750, 1689, 1490, 1597, 1263, 1160. Anal. Calcd for
C26H29NO5S: C, 66.79; H, 6.25; N, 3.00. Found: C, 66.77; H, 6.25; N,
3.01.
1
1j: Compound 1j was prepared according to method A. H NMR
(400 MHz, CDCl3): δ 7.72−7.69 (d, J = 8.0 Hz, 2H), 7.21−7.17 (m,
4H), 6.84−6.82 (d, J = 8.8 Hz, 1H), 5.95 (s, 1H), 5.11−5.07 (t, J = 7.2
Hz, 1H), 4.23−4.11 (m, 2H), 3.83−3.71 (m, 2H), 3.80 (s, 3H), 3.78
(s, 3H), 2.35 (s, 3H), 1.69 (s, 3 H), 1.57 (s, 3H); 13C NMR (100
MHz, CDCl3) δ 160.2, 154.7, 143.3, 139.1, 135.8, 131.7, 129.6, 129.4,
129.1, 128.0, 127.7, 117.7, 113.8, 81.4, 81.3, 68.9, 55.3, 54.9, 44.0, 35.7,
25.8, 21.4, 17.7; IR (neat, cm−1) 3396, 2924, 2359, 1748, 1383, 1249.
Anal. Calcd for C25H29NO6S: C, 63.67; H, 6.20; N, 2.97. Found: C,
63.64; H, 6.18; N, 2.99.
1k: Compound 1k was prepared according to method A. 1H NMR
(400 MHz, CDCl3): δ 7.71−7.68 (d, J = 8.0 Hz, 2H), 7.27−7.18 (m,
3H), 6.90−6.82 (m, 3H), 5.96 (s, 1H), 5.11−5.07 (t, J = 7.2 Hz, 1H),
4.22−4.10 (m, 2H), 3.84−3.71 (m, 8H), 2.34 (s, 3H), 1.69 (s, 3H),
1.56 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 159.6, 154.6, 143.4,
139.1, 137.2, 135.7, 129.6, 129.4, 127.6, 119.5, 117.7, 114.5, 112.9,
81.4, 81.1, 69.0, 55.2, 54.9, 44.0, 35.6, 25.7, 21.4, 17.5; IR (neat, cm−1)
3394, 2921, 1751, 1383, 1257. Anal. Calcd for C25H29NO6S: C, 63.67;
H, 6.20; N, 2.97. Found: C, 63.69; H, 6.19; N, 2.95.
1
1r: Compound 1r was prepared according to method B. H NMR
(400 MHz, CDCl3): δ 7.74−7.72 (d, J = 8.0 Hz, 2H), 7.32−7.29 (d, J
= 8.4 Hz, 2H), 5.11−5.07 (m, 1H), 4.44−4.43 (t, J = 2.0 Hz, 2H),
4.10−4.08 (t, J = 2.2 Hz, 2H), 3.79−3.76 (m, 5H), 2.43 (s, 3H), 1.72
(s, 3H), 1.65−1.63 (d, J = 5.2 Hz, 3H); 13C NMR (100 MHz, CDCl3)
δ 155.0, 143.4, 139.1, 135.9, 129.3, 127.8, 117.8, 80.8, 78.6, 55.2, 55.1,
44.1, 35.6, 25.8, 21.5, 17.7; IR (neat, cm−1) 3395, 2922, 1754, 1443,
1379, 1346, 1265, 1158. Anal. Calcd for C18H23NO5S: C, 59.16; H,
6.34; N, 3.83. Found: C, 59.15; H, 6.33; N, 3.85.
1
1l: Compound 1l was prepared according to method A. H NMR
1
1s: Compound 1s was prepared according to method B. H NMR
(400 MHz, CDCl3): δ 7.72−7.69 (d, J = 8.4 Hz, 2H), 7.34−7.32 (t, J =
4.4 Hz 13H), 7.30−7.17 (m, 3H), 6.91−6.84 (m, 2H), 6.41 (s, 1H),
5.11−5.07 (t, J = 7.2 Hz, 1H), 4.24−4.11 (m, 2H), 3.85−3.70 (m,
8H), 2.32 (s, 3H), 1.69 (s, 3H), 1.57 (s, 3H); 13C NMR (100 MHz,
CDCl3) δ 156.5, 154.6, 143.3, 139.0, 135.8, 130.5, 129.4, 128.7, 127.6,
123.8, 120.4, 117.8, 114.5, 110.6, 81.4, 80.7, 63.9, 55.5, 54.8, 44.0, 35.7,
25.8, 21.4, 17.6; IR (neat, cm−1) 3404, 2922, 1751, 1383, 1260. Anal.
Calcd for C25H29NO6S: C, 63.67; H, 6.20; N, 2.97. Found: C, 63.66;
H, 6.20; N, 2.98.
(400 MHz, CDCl3): δ 7.74−7.72 (d, J = 8.4 Hz, 2H), 7.30−7.28 (d, J
= 8.0 Hz, 2H), 5.14−5.09 (m, 1H), 4.12 (s, 2H), 3.83−3.81 (d, J = 7.2
Hz, 2H), 3.72 (s, 3H), 2.42 (s, 3H), 1.73 (s, 3H), 1.68 (s, 3H), 1.43 (s,
3H); 13C NMR (100 MHz, CDCl3) δ 153.2, 143.2, 138.9, 136.4,
129.4, 127.7, 118.1, 85.5, 77.9, 73.6, 54.2, 43.9, 35.6, 28.4, 25.8, 21.4,
17.7; IR (neat, cm−1) 3393, 2922, 1752, 1596, 1381. Anal. Calcd for
C20H27NO5S: C, 61.05; H, 6.92; N, 3.56. Found: C, 61.06; H, 6.91; N,
3.55.
1
1m: Compound 1m was prepared according to method A. 1H NMR
(400 MHz, CDCl3): δ 7.71−7.69 (d, J = 8.4 Hz, 2H), 7.20−7.18 (d, J
= 8.0 Hz, 2H), 6.89−6.78 (m, 3H), 6.39−6.37 (t, J = 1.4 Hz, 1H),
5.11−5.07 (t, J = 7.4 Hz, 1H), 4.22−4.10 (m, 2H), 3.83−3.71 (m,
11H), 2.33 (s, 3H), 1.69 (s, 3H), 1.58 (s, 3H); 13C NMR (100 MHz,
CDCl3) δ 154.6, 153.4, 150.6, 143.4, 139.1, 135.7, 129.4, 127.6, 124.8,
117.8, 114.9, 114.5, 111.8, 81.3, 80.8, 63.8, 56.1, 55.6, 54.8, 43.9, 35.7,
25.7, 21.3, 17.6; IR (neat, cm−1) 3413, 2956, 2829, 1752, 1500, 1256.
Anal. Calcd for C26H31NO7S: C, 62.26; H, 6.23; N, 2.79. Found: C,
62.24; H, 6.24; N, 2.80.
1t: Compound 1t was prepared according to method A. H NMR
(400 MHz, CDCl3): δ 7.54−7.52 (m, 2H), 7.41−7.33 (m, 3H), 6.34
(s, 1H), 5.35 −5.30 (m, 1H), 4.22−4.21 (d, J = 1.6 Hz, 2H), 4.05−
4.03 (d, J = 7.2 Hz, 2H), 3.79 (s, 3H), 1.75 (s, 3H), 1.66 (s, 3H); 13C
NMR (100 MHz, CDCl3) δ 154.8, 138.5, 136.2, 129.2, 128.6, 127.6,
120.1, 84.7, 81.9, 69.6, 65.9, 56.9, 55.0, 25.7, 17.9; IR (neat, cm−1)
3398, 2921, 2359, 1751, 1258. Anal. Calcd for C17H20O4: C, 70.81; H,
6.99. Found: C, 70.83; H, 6.97.
1u: Compound 1u was prepared according to method B. 1H NMR
(400 MHz, CDCl3): δ 7.75−7.73 (d, J = 8.0 Hz, 2H), 7.31−7.29 (d, J
= 7.6 Hz, 2H), 5.14−5.11 (m, 1H), 4.15 (s, 2H), 3.83−3.81 (d, J = 7.2
Hz, 2H), 3.73−3.72 (t, J = 1.4 Hz, 3H), 2.40 (s, 3H), 2.32−2.25 (m,
2H), 2.20−2.15 (m, 2H), 1.83−1.79 (m, 1H), 1.78 (s, 3H), 1.72 (s,
3H), 1.67−1.61 (m, 1H); 13C NMR (100 MHz, CDCl3) δ 153.2,
143.2, 138.7, 136.2, 129.4, 127.5, 117.9, 84.8, 78.2, 73.1, 54.3, 43.8,
35.8, 35.6, 25.7, 21.3, 17.6, 13.7; IR (neat, cm−1) 3393, 2922, 1752,
1596, 1381. Anal. Calcd for C21H27NO5S: C, 62.20; H, 6.71; N, 3.45.
Found: C, 62.22; H, 6.70; N, 3.43.
1n: Compound 1n was prepared according to method A. 1H NMR
(400 MHz, CDCl3): δ 7.74−7.61 (m, 7H), 7.54−7.47 (m, 2H), 7.35−
7.32 (m, 1H), 7.11−7.09 (d, J = 8.0 Hz, 2H), 6.16 (s, 1H), 5.12−5.08
(t, J = 7.2 Hz, 1H), 4.26−4.14 (m, 2H), 3.84−3.72 (m, 5H), 2.18 (s,
3H), 1.68 (s, 3H), 1.55 (s, 3H) ; 13C NMR (100 MHz, CDCl3) δ
154.7, 143.4, 139.2, 135.8, 133.5, 133.2, 132.8, 129.4, 128.6, 128.2,
127.6, 126.9, 126.8, 126.5, 124.6, 117.8, 81.9, 81.3, 69.4, 55.1, 44.1,
35.7, 25.8, 21.3, 17.7; IR (neat, cm−1) 3398, 2922, 2362, 1750, 1381,
2767
dx.doi.org/10.1021/jo202590w | J. Org. Chem. 2012, 77, 2763−2772

The Journal of Organic Chemistry
Article
General Procedure for the Palladium Catalyzed Cyclization
Reactions of Enyne Carbonates 1 To Form 3-Vinylidene-1-
tosylpyridines 2. A mixture of methyl 4-(4-methyl-N-(3-methylbut-
2-enyl)phenylsulfonamido)-1-phenylbut-2-ynyl carbonate 1a (88.3
mg, 0.2 mmol), PdI2 (7.2 mg, 10 mol %), Et3N (40 mg, 0.4 mmol),
P(2-furyl)3 (18.6 mg, 40 mol %), TBHP (0.08 mL, 0.4 mmol), and
DMF (2 mL) was added to a 20 mL tube under an argon atmosphere.
The resulting mixture was then stirred at 85 °C. When the reaction
was considered complete as determined by TLC, the reaction mixture
was allowed to cool to room temperature, quenched with a saturated
aqueous solution of ammonium chloride, and extracted with ethyl
acetate. The combined organic extracts were washed with water and
saturated brine, dried over Na2SO4, and filtered. Solvent was
evaporated under reduced pressure. The residue was purified by
chromatography on silica gel using mixtures of hexanes and EtOAc to
afford 2a (54.8 mg, 75%).
ESIHRMS: Found: m/z 466.0444. Calcd for C22H22BrNNaO2S: (M +
Na)+ 466.0447.
2f: The reaction mixture was chromatographed using 50:1 hexanes/
EtOAc to afford 47.8 mg (61%) of the indicated compound after 2 h.
1H NMR (400 MHz, CDCl3): δ 7.68−7.65 (d, J = 8.0 Hz, 2H), 7.28−
7.26 (d, J = 8.0 Hz, 2H), 7.06−7.04 (d, J = 8.0 Hz, 2H), 7.00−6.97 (d,
J = 8.4 Hz, 2H), 6.62−6.59 (d, J = 8.4 Hz, 1H), 6.05 (s, 1H), 4.96−
4.94 (d, J = 8.0 Hz, 1H), 4.15−4.05 (m, 2H), 2.43 (s, 3H), 2.32 (s,
3H), 1.13 (s, 3H), 1.03 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
200.2, 143.6, 136.9, 135.2, 131.1, 129.6, 129.3, 127.2, 126.5, 122.9,
119.6, 106.0, 96.9, 44.8, 33.8, 29.8, 29.0, 21.6, 21.4; IR (neat, cm−1)
3443, 2963, 2923, 1955, 1712, 1355, 1166, 681, 548. ESIHRMS:
Found: m/z 402.1487. Calcd for C23H25NNaO2S: (M + Na)+
402.1498.
2g: The reaction mixture was chromatographed using 50:1
hexanes/EtOAc to afford 48.6 mg (64%) of the indicated compound
Characterization Data of Six-Membered Heterocycles 2a−
2q, 2r, 2s. 2a: The reaction mixture was chromatographed using 50:1
hexanes/EtOAc to afford 54.8 mg (75%) of the indicated compound
1
after 2 h. H NMR (400 MHz, CDCl3): δ 7.68−7.65 (d, J = 8.0 Hz,
2H), 7.29−7.26 (d, J = 8.0 Hz, 2H), 7.15−7.11 (t, J = 7.6 Hz, 1H),
7.01−6.99 (d, J = 8.4 Hz, 1H), 6.96 (s, 1H), 6.92−6.89 (d, J = 8.4 Hz,
1H), 6.61−6.59 (d, J = 8.4 Hz, 1H), 6.04 (s, 1H), 4.96−4.94 (d, J = 8.0
Hz, 1H), 4.16−4.04 (m, 2H), 2.42 (s, 3H), 2.31 (s, 3H), 1.15 (s, 3H),
1.13 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 200.5, 143.6, 138.2,
135.2, 134.0, 129.6, 128.5, 127.9, 127.4, 127.2, 123.7, 123.0, 119.6,
106.0, 97.2, 44.8, 33.8, 29.9, 28.9, 21.6, 21.3; IR (neat, cm−1) 3412,
2963, 2923, 1955, 1354, 1165, 679, 547. ESIHRMS: Found: m/z
402.1492. Calcd for C23H25NNaO2S: (M + Na)+ 402.1498.
1
after 2 h. H NMR (400 MHz, CDCl3): δ 7.68−7.66 (d, J = 8.0 Hz,
2H), 7.29−7.16 (m, 5H), 7.11−7.08 (t, J = 4.2 Hz, 1H), 6.62−6.60 (d,
J = 8.0 Hz, 1H), 6.08 (s, 1H), 4.97−4.94 (d, J = 8.0 Hz, 1H), 4.16−
4.06 (m, 2H), 2.42 (s, 3H), 1.14 (s, 3H), 1.04 (s, 3H); 13C NMR (100
MHz, CDCl3) δ 200.5, 143.6, 135.2, 134.1, 129.6, 128.6, 127.2, 127.1,
126.6, 122.9, 119.5, 106.2, 97.1, 44.7, 33.8, 29.7, 29.0, 21.6; IR (neat,
cm−1) 3398, 2963, 2361, 1948, 1644, 1355, 1164, 771, 680. ESIHRMS:
Found: m/z 388.1331. Calcd for C22H23NNaO2S: (M + Na)+
388.1342.
2h: The reaction mixture was chromatographed using 50:1
hexanes/EtOAc to afford 42.5 mg (56%) of the indicated compound
2b: The reaction mixture was chromatographed using 50:1
hexanes/EtOAc to afford 52.8 mg (66%) of the indicated compound
1
after 2 h. H NMR (400 MHz, CDCl3): δ 7.68−7.65 (d, J = 8.0 Hz,
1
2H), 7.28−7.26 (d, J = 8.0 Hz, 2H), 7.13−7.03 (m, 4H), 6.61−6.59
(d, J = 8.0 Hz, 1H), 6.23 (s, 1H), 4.97−4.94 (d, J = 8.0 Hz, 1H), 4.16−
4.03 (m, 2H), 2.42 (s, 3H), 2.31 (s, 3H), 1.14 (s, 3H), 1.05 (s, 3H);
13C NMR (100 MHz, CDCl3) δ 201.1, 143.6, 135.2, 134.9, 132.2,
130.5, 129.6, 127.3, 126.9, 126.1, 123.0, 119.6, 104.9, 94.3, 44.9, 33.6,
29.6, 28.9, 21.6, 19.8; IR (neat, cm−1) 2963, 2924, 1953, 1355, 1165,
680, 548. ESIHRMS: Found: m/z 402.1494. Calcd for
C23H25NNaO2S: (M + Na)+ 402.1498.
after 2 h. H NMR (400 MHz, CDCl3): δ 7.68−7.65 (d, J = 8.0 Hz,
2H), 7.28−7.26 (d, J = 8.0 Hz, 2H), 7.20−7.18 (d, J = 8.4 Hz, 2H),
7.00−6.98 (d, J = 8.4 Hz, 2H), 6.05 (s, 1H), 4.96−4.94 (d, J = 8.4 Hz,
1H), 4.14−4.06 (m, 2H), 2.42 (s, 3H), 1.12 (s, 3H), 1.04 (s, 3H); 13C
NMR (100 MHz, CDCl3) δ 200.5, 143.7, 135.2, 132.7, 132.6, 129.6,
128.7, 127.7, 127.2, 122.9, 119.3, 106.7, 96.2, 44.6, 33.9, 29.6, 29.1,
21.6; IR (neat, cm−1) 3424, 2963, 2923, 1955, 1490, 1355, 1165, 679,
547. ESIHRMS: Found: m/z 422.0957. Calcd for C22H22ClNNaO2S:
(M + Na)+ 422.0952.
2i: The reaction mixture was chromatographed using 50:1 hexanes/
EtOAc to afford 48.8 mg (62%) of the indicated compound after 2 h.
1H NMR (400 MHz, CDCl3): δ 7.68−7.65 (d, J = 8.0 Hz, 2H), 7.29−
7.26 (d, J = 8.0 Hz, 2H), 7.01−6.99 (d, J = 7.6 Hz, 1H), 6.92 (s, 1H),
6.85−6.82 (d, J = 7.6 Hz, 1H), 6.61−6.58 (d, J = 8.4 Hz, 1H), 6.03 (s,
1H), 4.97−4.94 (d, J = 8.4 Hz, 1H), 4.16−4.03 (m, 2H), 2.42 (s, 3H),
2.23 (s, 3H), 2.22 (s, 3H), 1.14 (s, 3H), 1.02 (s, 3H); 13C NMR (100
MHz, CDCl3) δ 200.2, 143.6, 136.7, 135.6, 135.2, 131.5, 129.9, 129.6,
127.9, 127.3, 124.0, 122.9, 119.7, 105.9, 96.9, 44.9, 33.8, 29.9, 28.9,
21.5, 19.7, 19.6; IR (neat, cm−1) 3403, 2963, 2922, 1955, 1355, 1166,
1026, 679, 545. ESIHRMS: Found: m/z 416.1668. Calcd for
C24H27NNaO2S: (M + Na)+ 416.1655.
2c: The reaction mixture was chromatographed using 50:1 hexanes/
EtOAc to afford 51.5 mg (64%) of the indicated compound after 2 h.
1H NMR (400 MHz, CDCl3): δ 7.68−7.65 (d, J = 8.0 Hz, 2H), 7.30−
7.27 (d, J = 8.4 Hz, 2H), 7.19−7.14 (m, 2H), 7.09 (s, 1H), 7.00−6.96
(m, 1H), 6.62−6.60 (d, J = 8.4 Hz, 1H), 6.03 (s, 1H), 4.96−4.94 (d, J
= 8.4 Hz, 1H), 4.16−4.04 (m, 2H), 2.42 (s, 3H), 1.14 (s, 3H), 1.04 (s,
3H); 13C NMR (100 MHz, CDCl3) δ 200.7, 143.7, 136.2, 135.1,
134.5, 129.8, 129.6, 127.2, 127.1, 126.4, 124.7, 123.0, 119.2, 106.8,
96.2, 44.5, 33.8, 29.8, 28.9, 21.6; IR (neat, cm−1) 3433, 2964, 1924,
1956, 1593, 1354, 1165, 680, 545. ESIHRMS: Found: m/z 422.0954.
Calcd for C22H22ClNNaO2S: (M + Na)+ 422.0952.
2j: The reaction mixture was chromatographed using 50:1 hexanes/
EtOAc to afford 49.0 mg (62%) of the indicated compound after 2 h.
1H NMR (400 MHz, CDCl3): δ 7.68−7.65 (d, J = 8.4 Hz, 2H), 7.29−
7.27 (d, J = 8.0 Hz, 2H), 7.04−7.01 (d, J = 8.8 Hz, 2H), 6.80−6.77 (d,
J = 8.8 Hz, 2H), 6.61−6.59 (d, J = 8.0 Hz, 1H), 6.05 (s, 1H), 4.96−
4.93 (d, J = 8.4 Hz, 1H), 4.14−4.04 (m, 2H), 3.79 (s, 3H), 2.43 (s,
3H), 1.12 (s, 3H), 1.03 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
199.8, 158.9, 143.6, 135.2, 129.6, 127.7, 127.2, 126.4, 122.9, 119.6,
114.1, 106.1, 96.6, 55.3, 44.9, 33.8, 29.8, 29.1, 21.6; IR (neat, cm−1)
3411, 2962, 2924, 1954, 1510, 1353, 1247, 1165, 1028, 680, 547.
ESIHRMS: Found: m/z 418.1438. Calcd for C23H25NNaO3S: (M +
Na)+ 418.1447.
2d: The reaction mixture was chromatographed using 50:1
hexanes/EtOAc to afford 50.4 mg (63%) of the indicated compound
after 2 h. H NMR (400 MHz, CDCl3): δ 7.68−7.66 (d, J = 8.0 Hz,
1
2H), 7.33−7.28 (m, 3H), 7.14−7.07 (m, 3H), 6.63−6.60 (d, J = 8.4
Hz, 1H), 6.46−6.45 (d, J = 1.8 Hz, 1H), 4.99−4.96 (d, J = 8.4 Hz,
1H), 4.16−4.07 (m, 2H), 2.43 (s, 3H), 1.15 (s, 3H), 1.04 (s, 3H); 13C
NMR (100 MHz, CDCl3) δ 200.7, 143.7, 136.2, 135.1, 134.5, 129.8,
129.6, 127.2, 127.1, 126.4, 124.7, 123.0, 119.2, 106.8, 96.2, 44.5, 33.8,
29.8, 28.9, 21.6; IR (neat, cm−1) 3395, 2964, 2923, 1956, 1644, 1355,
1193, 1028, 754, 679, 547. ESIHRMS: Found: m/z 422.0958. Calcd
for C22H22ClNNaO2S: (M + Na)+ 422.0952.
2e: The reaction mixture was chromatographed using 50:1 hexanes/
EtOAc to afford 32.0 mg (36%) of the indicated compound after 2 h.
1H NMR (400 MHz, CDCl3): δ 7.68−7.65 (d, J = 8.0 Hz, 2H), 7.36−
7.32 (m, 2H), 7.28−7.25 (m, 2H), 6.94−6.90 (m, 2H), 6.63−6.61 (d, J
= 8.0 Hz, 1H), 6.04−6.03 (t, J = 1.6 Hz, 1H), 4.96−4.94 (d, J = 8.4
Hz, 1H), 4.15−4.06 (m, 2H), 2.43 (s, 3H), 1.12 (s, 3H), 1.05 (s, 3H);
13C NMR (100 MHz, CDCl3) δ 200.6, 143.7, 135.2, 133.1, 131.7,
129.7, 128.1, 127.2, 123.0, 120.7 119.2, 106.8, 96.3, 44.5, 33.9, 29.6,
29.2, 21.6; IR (neat, cm−1) 3396, 2962, 2923, 1355, 1165, 681, 547.
2k: The reaction mixture was chromatographed using 50:1
hexanes/EtOAc to afford 48.3 mg (61%) of the indicated compound
1
after 2 h. H NMR (400 MHz, CDCl3): δ 7.67−7.65 (d, J = 8.0 Hz,
2H), 7.29−7.26 (d, J = 8.0 Hz, 2H), 7.19−7.14 (t, J = 4.0 Hz, 1H),
6.76−6.70 (m, 3H), 6.61−6.58 (d, J = 8.0 Hz, 1H), 6.05 (s, 1H),
4.96−4.94 (d, J = 8.4 Hz, 1H), 4.16−4.04 (m, 2H), 3.76 (s, 3H), 2.42
(s, 3H), 1.15 (s, 3H), 1.04 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
200.6, 159.8, 143.7, 135.6, 135.2, 129.6, 129.5, 127.2, 123.0, 119.5,
2768
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Article
119.3, 112.6, 112.1, 106.3, 97.1, 55.1, 44.7, 33.8, 29.9, 28.9, 21.5; IR
(neat, cm−1) 3403, 2963, 2926, 1956, 1598, 1354, 1165, 1028, 681,
546. ESIHRMS: Found: m/z 418.1440. Calcd for C23H25NNaO3S: (M
+ Na)+ 418.1447.
5.91 (d, J = 10.4 Hz, 1H), 4.97−4.94 (d, J = 8.0 Hz, 1H), 4.09−4.02
(m, 2H), 2.42 (s, 3H), 1.06 (s, 3H), 1.02 (s, 3H); 13C NMR (100
MHz, CDCl3) δ 203.5, 143.6, 137.1, 135.3, 131.1, 129.6, 128.6, 127.5,
127.3, 126.2, 124.5, 123.1, 120.2, 103.8, 97.2, 44.9, 33.6, 29.7, 29.5,
29.1, 21.6; IR (neat, cm−1) 3411, 2959, 2923, 1948, 1355, 1165, 1025,
746, 680, 547. ESIHRMS: Found: m/z 414.1502. Calcd for
C24H25NNaO2S: (M + Na)+ 414.1499.
2r: The reaction mixture was chromatographed using 50:1 hexanes/
EtOAc to afford 17.9 mg (31%) of the indicated compound after 2 h.
1H NMR (400 MHz, CDCl3): δ 7.66−7.64 (d, J = 8.0 Hz, 2H), 7.28−
7.27 (d, J = 8.0 Hz, 2H), 6.53−6.50 (d, J = 8.4 Hz, 1H), 4.95−4.92 (d,
J = 8.4 Hz, 1H), 4.61−4.60 (t, J = 2.0 Hz, 2H), 4.01−3.99 (t, J = 2.0
Hz, 1H), 2.42 (s, 3H), 0.98 (s, 6H); 13C NMR (100 MHz, CDCl3) δ
203.9, 143.6, 135.1, 129.4, 127.4, 123.2, 120.9, 101.1, 45.1, 32.5, 28.9,
21.5; IR (neat, cm−1) 3397, 2962, 2924, 1960, 1454, 1382, 1355, 1165,
1029, 675, 545. ESIHRMS: Found: m/z 312.1021. Calcd for
C16H19NNaO2S: (M + Na)+ 312.1029.
2l: The reaction mixture was chromatographed using 50:1 hexanes/
EtOAc to afford 43.5 mg (55%) of the indicated compound after 2 h.
1H NMR (400 MHz, CDCl3): δ 7.68−7.65 (d, J = 8.0 Hz, 2H), 7.28−
7.26 (d, J = 8.0 Hz, 2H), 7.18−7.14 (m, 1H), 7.06−7.04 (m, 1H),
6.85−6.79 (m, 2H), 6.61−6.58 (d, J = 8.4 Hz, 1H), 6.45 (s, 1H),
4.97−4.94 (d, J = 8.4 Hz, 1H), 4.15−4.05 (m, 2H), 3.83 (s, 3H), 2.43
(s, 3H), 1.13 (s, 3H), 1.03 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
200.9, 155.9, 143.6, 135.3, 129.6, 128.1, 127.5, 127.2, 123.0, 122.5,
120.7, 119.9, 110.9, 105.1, 91.1, 55.5, 44.9, 33.7, 29.7, 28.9, 21.6; IR
(neat, cm−1) 3410, 2962, 2923, 1954, 1354, 1246, 1165, 1027, 680,
547. ESIHRMS: Found: m/z 418.1442. Calcd for C23H25NNaO3S: (M
+ Na)+ 418.1447.
2m: The reaction mixture was chromatographed using 50:1
hexanes/EtOAc to afford 42.3 mg (50%) of the indicated compound
2s: The reaction mixture was chromatographed using 50:1 hexanes/
EtOAc to afford 44.5 mg (70%) of the indicated compound after 2 h.
1H NMR (400 MHz, CDCl3): δ 7.68−7.65 (d, J = 8.4 Hz, 2H), 7.29−
7.26 (d, J = 8.4 Hz, 2H), 6.55−6.52 (d, J = 8.4 Hz, 1H), 4.90−4.88 (d,
J = 8.0 Hz, 1H), 3.94 (s, 2H), 2.40 (s, 3H), 1.54 (s, 6H), 0.97 (s, 6H);
13C NMR (100 MHz, CDCl3) δ 196.9, 143.4, 135.5, 129.5, 127.2,
1
after 2 h. H NMR (400 MHz, CDCl3): δ 7.67−7.64 (d, J = 8.4 Hz,
2H), 7.29−7.25 (t, J = 5.6 Hz, 2H), 6.79−6.77 (t, J = 4.6 Hz, 1H),
6.73−6.70 (t, J = 5.4 Hz, 2H), 6.59−6.56 (d, J = 8.4 Hz, 2H), 6.42−
6.41 (d, J = 1.6 Hz, 1H), 4.96−4.94 (d, J = 8.4 Hz, 1H), 4.15−4.04 (m,
2H), 3.79 (s, 3H), 3.71 (s, 3H), 2.42 (s, 3H), 1.15 (s, 3H), 1.02 (s,
3H); 13C NMR (100 MHz, CDCl3) δ 200.9, 153.6, 150.6, 143.7,
135.1, 129.6, 127.2, 123.5, 123.0, 119.8, 113.1, 112.8, 112.3, 105.5,
91.2, 56.3, 55.5, 44.9, 33.7, 29.9, 28.8, 21.5; IR (neat, cm−1) 3394,
2961, 2924, 1955, 1501, 1354, 1166, 1026, 680, 546. ESIHRMS:
Found: m/z 448.1556. Calcd for C24H27NNaO4S: (M + Na)+
448.1553.
122.7, 120.2, 100.0, 98.1, 45.3, 33.3, 29.4, 21.5, 20.4; IR (neat, cm−1)
3406, 3020, 2962, 2925, 1711, 1219, 759, 667, 547. ESIHRMS: Found:
m/z 340.1344. Calcd for C18H23NNaO2S: (M + Na)+ 340.1342.
General Procedure for the Palladium-Catalyzed Cyalization
Reactions of Enyne Carbonates 1 To Form 3-Vinylidene-1-
tosylpyrrolidines 3. A mixture of 1,6-enyne carbonate 1a (88.3 mg,
0.2 mmol), Pd(dba)2 (11.5 mg, 10 mol %), KOAc (39 mg, 0.4 mmol),
P(2-furyl)3 (4.6 mg, 10 mol %), and DMF (2 mL) was added to a 20
mL tube under an argon atmosphere. The resulting mixture was then
stirred at 85 °C. When the reaction was considered complete as
determined by TLC, the reaction mixture was allowed to cool to room
temperature, quenched with a saturated aqueous solution of
ammonium chloride, and extracted with ethyl acetate. The combined
organic extracts were washed with water and saturated brine, dried
over Na2SO4, and filtered. Solvent was evaporated under reduced
pressure. The residue was purified by chromatography on silica gel
using mixtures of hexanes and EtOAc to afford 3a (70.2 mg, 96%).
Characterization Data of Five-Membered Heterocycles 3a−
3o, 3s. 3a: The reaction mixture was chromatographed using 30:1
hexanes/EtOAc to afford 70.2 mg (96%) of the indicated compound
2n: The reaction mixture was chromatographed using 50:1
hexanes/EtOAc to afford 45.1 mg (53%) of the indicated compound
after 2 h. 1H NMR (400 MHz, CDCl3): δ 7.78−7.73 (m, 2H), 7.69−
7.65 (t, J = 7.8 Hz, 3H), 7.55 (s, 1H), 7.48−7.40 (m, 2H), 7.28−7.25
(d, J = 8.0 Hz, 2H), 7.19−7.17 (m, 1H), 6.65−6.62 (d, J = 8.0 Hz,
1H), 6.26 (s, 1H), 4.99−4.96 (d, J = 8.4 Hz, 1H), 4.21−4.11 (m, 2H),
2.38 (s, 3H), 1.17 (s, 3H), 1.07 (s, 3H); 13C NMR (100 MHz, CDCl3)
δ 201.1, 143.7, 135.2, 133.6, 132.7, 131.6, 129.6, 128.3, 127.7, 127.6,
127.2, 126.3, 125.7, 125.6, 124.2, 123.0, 119.5, 106.4, 97.5, 44.8, 33.8,
29.8, 29.1, 21.5; IR (neat, cm−1) 3395, 2963, 2924, 1954, 1355, 1165,
1026, 679, 547. ESIHRMS: Found: m/z 438.1502. Calcd for
C26H25NNaO2S: (M + Na)+ 438.1498.
2o: The reaction mixture was chromatographed using 50:1
hexanes/EtOAc to afford 42.4 mg (57%) of the indicated compound
1
1
after 4 h. H NMR (400 MHz, CDCl3): δ 7.76−7.71 (m, 2H), 7.38−
after 2 h. H NMR (400 MHz, CDCl3): δ 7.68−7.65 (d, J = 8.4 Hz,
7.35 (d, J = 8.4 Hz, 2H), 7.29−7.25 (m, 1H), 7.22−7.19 (m, 1H),
7.18−7.15 (d, J = 7.2 Hz, 2H), 6.29−6.25 (m, 1H), 4.84−4.77 (m,
1H), 4.13−3.89 (m, 2H), 3.62−3.42 (m, 2H), 3.29−3.18 (m, 1H),
2.42 (s, 3H), [1.68(s), 1.66(s), 3H]; 13C NMR (100 MHz, CDCl3) δ
198.0, 143.8, 142.5, 133.7, 132.8, 129.7, 128.6, 127.9, 127.4, 127.0,
113.3, 105.0, 99.4, 99.3, 52.3, 49.8, 49.5, 49.0, 21.6, 19.8; IR (neat,
cm−1) 3420, 2924, 1722, 1346, 1163, 1093, 767, 666, 548. ESIHRMS:
Found: m/z 366.1524. Calcd for C22H24NO2S: (M + H)+ 366.1522.
3b: The reaction mixture was chromatographed using 30:1
hexanes/EtOAc to afford 44.0 mg (55%) of the indicated compound
2H), 7.30−7.27 (d, J = 8.0 Hz, 2H), 7.12−7.10 (d, J = 5.2 Hz, 1H),
6.93−6.90 (m, 1H), 6.82−6.81 (d, J = 3.2 Hz, 1H), 6.60−6.58 (d, J =
8.0 Hz, 1H), 6.29 (s, 1H), 4.96−4.93 (d, J = 8.0 Hz, 1H), 4.18−4.14
(m, 2H), 2.43 (s, 3H), 1.16 (s, 3H), 1.02 (s, 3H); 13C NMR (100
MHz, CDCl3) δ 199.9, 143.6, 138.5, 135.2, 129.6, 127.4, 127.3, 124.9,
124.4, 123.0, 119.6, 106.5, 91.4, 44.7, 34.0, 29.9, 28.7, 21.6; IR (neat,
cm−1) 3408, 2964, 2924, 1955, 1355, 1166, 1026, 681, 546. ESIHRMS:
Found: m/z 394.0899. Calcd for C20H21NNaO2S2: (M + Na)+
394.0906.
2p: The reaction mixture was chromatographed using 50:1
hexanes/EtOAc to afford 32.5 mg (49%) of the indicated compound
1
after 4 h. H NMR (400 MHz, CDCl3): δ 7.76−7.73 (d, J = 7.6 Hz,
1
2H), 7.38−7.36 (d, J = 7.6 Hz, 2H), 7.25−7.22 (m, 2H), 7.10−7.07
(d, J = 8.4 Hz, 2H), 6.25−6.22 (m, 1H), 4.83−4.77 (m, 1H), 4.12−
3.88 (m, 2H), 3.62−3.45 (m, 2H), 3.30−3.13 (m, 1H), 2.47 (s, 3H),
[1.67(s), 1.66(s), 3H]; 13C NMR (100 MHz, CDCl3) δ 198.1, 197.9,
143.9, 142.4, 142.0, 133.0, 132.7, 132.4, 132.3, 129.8, 128.8, 128.7,
128.2, 128.1, 127.9, 113.4, 113.3, 105.5, 105.4, 98.5, 98.4, 52.2, 49.7,
49.5, 49.1, 21.6, 19.8, 19.5; IR (neat, cm−1) 3408, 2925, 1721, 1594,
1346, 1163, 1092, 816, 768, 667, 548. ESIHRMS: Found: m/z
400.1132. Calcd for C22H23ClNO2S: (M + H)+ 400.1133.
after 2 h. H NMR (400 MHz, CDCl3): δ 7.67−7.64 (d, J = 8.0 Hz,
2H), 7.29−7.27 (d, J = 8.0 Hz, 2H), 6.54−6.52 (d, J = 8.0 Hz, 1H),
5.08−5.04 (m, 1H), 4.91−4.89 (d, J = 8.4 Hz, 1H), 4.02−3.91 (m,
2H), 2.42 (s, 3H), 1.90−1.75 (m, 2H), 1.37−1.28 (m, 2H), 1.01 (s,
3H), 0.96 (s, 3H), 0.90−0.86 (t, J = 7.4 Hz, 2H); 13C NMR (100
MHz, CDCl3) δ 199.3, 143.4, 135.4, 129.5, 127.3, 122.9, 120.3, 101.9,
93.8, 45.4, 32.9, 31.9, 30.9, 29.7, 29.0, 22.4, 21.5, 13.7; IR (neat, cm−1)
3412, 2959, 2921, 1712, 1382, 1358, 1165, 1029, 756, 672, 547.
ESIHRMS: Found: m/z 354.1497. Calcd for C19H25NNaO2S: (M +
Na)+ 354.1498.
3c: The reaction mixture was chromatographed using 30:1 hexanes/
EtOAc to afford 63.2 mg (79%) of the indicated compound after 4 h.
1H NMR (400 MHz, CDCl3): δ 7.78−7.73 (m, 2H), 7.39−7.31 (m,
2H), 7.25−7.10 (m, 3H), 7.06−7.02 (m, 1H), 6.23−6.19 (m, 1H),
4.83−4.78 (m, 1H), 4.41−3.87 (m, 2H), 3.61−3.50 (m, 2H), 3.47−
3.16 (m, 1H), 2.46 (s, 3H), [1.68(s), 1.66(s), 3H]; 13C NMR (100
2q: The reaction mixture was chromatographed using 50:1
hexanes/EtOAc to afford 23.5 mg (30%) of the indicated compound
1
after 2 h. H NMR (400 MHz, CDCl3): δ 7.69−7.66 (d, J = 8.0 Hz,
2H), 7.36−7.29 (m, 6H), 7.25−7.21 (m, 1H), 6.58−6.56 (d, J = 8.0
Hz, 1H), 6.49−6.45 (d, J = 15.6 Hz, 1H), 6.34−6.27 (m, 1H), 5.94−
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MHz, CDCl3) δ 198.3, 198.1, 144.0, 143.9, 142.4, 142.0, 138.6, 135.9,
135.7, 134.6, 132.6, 129.9, 129.8, 129.8, 127.8, 127.5, 127.4, 127.3,
126.9, 126.7, 126.1, 125.2, 125.1, 124.8, 122.0, 118.1, 113.5, 105.7,
105.6, 98.5, 52.2, 52.1, 49.7, 49.5, 49.1, 22.7, 21.6, 19.8, 19.5; IR (neat,
cm−1) 3410, 2925, 2924, 2858, 1594, 1457, 1346, 1164, 1094, 816,
755, 666, 547. ESIHRMS: Found: m/z 400.1136. Calcd for
C22H23ClNO2S: (M + H)+ 400.1133.
3d: The reaction mixture was chromatographed using 30:1
hexanes/EtOAc to afford 53.6 mg (67%) of the indicated compound
after 4 h. 1H NMR (400 MHz, CDCl3): δ 7.78−7.73 (m, 2H), 7.38−
7.34 (m, 2H), 7.33−7.30 (m, 2H), 7.26−7.10 (m, 2H), 6.76−6.68 (m,
1H), 4.84−4.77 (m, 2H), 4.14−3.89 (m, 2H), 3.63−3.45 (m, 2H),
3.33−3.15 (m, 1H), [2.46(s), 2.43(s), 3H], [1.68(s), 1.67(s), 3H]; 13C
NMR (100 MHz, CDCl3) δ 198.9, 198.8, 143.9, 143.6, 142.6, 141.9,
132.6, 132.2, 131.6, 131.5, 130.6, 129.9, 129.8, 129.7, 128.9, 128.6,
128.4, 128.4, 127.9, 127.5, 127.3, 126.9, 126.8, 126.3, 113.5, 113.3,
105.2, 105.1, 95.8, 95.7, 52.2, 49.8, 49.4, 49.2, 21.6, 19.8, 19.5; IR
(neat, cm−1) 3396, 2922, 2848, 1382, 1346, 1162, 1093, 1036, 815,
757, 665, 547. ESIHRMS: Found: m/z 400.1138. Calcd for
C22H23ClNO2S: (M + H)+ 400.1133.
3e: The reaction mixture was chromatographed using 30:1 hexanes/
EtOAc to afford 49.8 mg (56%) of the indicated compound after 4 h.
1H NMR (400 MHz, CDCl3): δ 7.54−7.53 (d, J = 8.0 Hz, 2H), 7.39−
7.35 (t, J = 7.0 Hz, 4H), 7.03−7.01 (d, J = 8.4 Hz, 2H), 6.22−6.20 (t, J
= 3.6 Hz, 1H), 4.82−4.77 (m, 2H), 4.12−3.88 (m, 2H), 3.62−3.46 (m,
2H), 3.30−3.14 (m, 1H), 2.47 (s, 3H), [1.67(s), 1.65(s), 3H]; 13C
NMR (100 MHz, CDCl3) δ 198.1, 198.0, 143.9, 142.4, 142.0, 132.9,
132.8, 132.7, 131.8, 131.7, 129.8, 128.5, 128.4, 127.9, 121.1, 121.1,
113.4, 113.3, 105.6, 105.5, 98.6, 98.5, 52.2, 49.7, 49.5, 49.1, 21.6, 19.8,
19.5; IR (neat, cm−1) 3417, 2924, 2858, 1486, 1347, 1163, 1093, 1035,
816, 756, 665, 548. ESIHRMS: Found: m/z 444.0615. Calcd for
C22H23BrNO2S: (M + H)+ 444.0627.
3f: The reaction mixture was chromatographed using 30:1 hexanes/
EtOAc to afford 65.3 mg (86%) of the indicated compound after 4 h.
1H NMR (400 MHz, CDCl3): δ 7.75−7.73 (t, J = 4.0 Hz, 2H), 7.37−
7.35 (d, J = 8.0 Hz, 2H), 7.09−7.03 (m, 4H), 6.26−6.22 (m, 1H),
4.83−4.76 (m, 2H), 4.11−3.87 (m, 2H), 3.61−3.43 (m, 2H), 3.31−
3.14 (m, 1H), 2.46 (s, 3H), [2.32(s), 2.31(s), 3H], [1.68(s), 1.65(s),
3H]; 13C NMR (100 MHz, CDCl3) δ 197.7, 197.6, 143.8, 142.6,
142.2, 137.3, 132.7, 130.8, 130.6, 129.7, 129.7, 129.3, 129.3, 127.8,
126.9, 113.1, 104.8, 104.7, 99.2, 99.1, 52.2, 49.8, 49.5, 49.0, 21.6, 21.2,
19.8, 19.5; IR (neat, cm−1) 3407, 2923, 2361, 1721, 1382, 1346, 1162,
1092, 1037, 814, 771, 666, 548. ESIHRMS: Found: m/z 380.1683.
Calcd for C23H26NO2S: (M + H)+ 380.1679.
548. ESIHRMS: Found: m/z 380.1683. Calcd for C23H26NO2S: (M +
H)+ 380.1679.
3i: The reaction mixture was chromatographed using 30:1 hexanes/
EtOAc to afford 51.2 mg (65%) of the indicated compound after 4 h.
1H NMR (400 MHz, CDCl3): δ 7.76−7.73 (t, J = 4.0 Hz, 2H), 7.37−
7.35 (d, J = 8.0 Hz, 2H), 7.04−7.01 (m, 1H), 6.95−6.89 (m, 2H),
6.23−6.20 (t, J = 4.0 Hz, 1H), 4.84−4.76 (m, 2H), 4.12−3.86 (m,
2H), 3.59−3.47 (m, 2H), 3.31−3.00 (m, 1H), 2.46 (s, 3H), [2.22(s),
2.20(s), 6H], [1.69(s), 1.65(s), 3H]; 13C NMR (100 MHz, CDCl3) δ
197.7, 197.6, 143.8, 142.6, 142.2, 136.8, 136.7, 136.0, 132.6, 131.2,
131.0, 129.9, 129.7, 128.3, 128.1, 127.8, 124.5, 124.4, 113.1, 104.6,
104.5, 99.2, 99.1, 52.2, 52.1, 49.8, 49.4, 48.9, 21.6, 19.7, 19.5; IR (neat,
cm−1) 3418, 2923, 1641, 1348, 1163, 1093, 1034, 814, 753, 665, 548;
ESIHRMS: Found: m/z 394.1826. Calcd for C24H28NO2S: (M + H)+
394.1835.
3j: The reaction mixture was chromatographed using 30:1 hexanes/
EtOAc to afford 55.4 mg (70%) of the indicated compound after 4 h.
1H NMR (400 MHz, CDCl3): δ 7.76−7.73 (t, J = 4.0 Hz, 2H), 7.37−
7.35 (d, J = 8.0 Hz, 2H), 7.10−7.07 (d, J = 8.4 Hz, 2H), 6.83−6.79 (m,
2H), 6.26−6.21 (m, 1H), 4.84−4.76 (m, 2H), 4.11−3.86 (m, 2H),
[3.79(s), 3.78(s), 3H], 3.61−3.43 (m, 2H), 3.29−3.15 (m, 1H), 2.46
(s, 3H), [1.68(s), 1.65(s), 3H]; 13C NMR (100 MHz, CDCl3) δ 197.3,
197.2, 159.1, 159.0, 143.8, 142.6, 142.3, 132.7, 129.7, 128.1, 127.8,
126.0, 125.9, 114.1, 113.1, 104.8, 104.7, 98.8, 98.7, 52.2, 52.1, 49.8,
49.5, 48.9, 21.5, 19.8, 19.5; IR (neat, cm−1) 3434, 2927, 1602, 1345,
1164, 1093, 1032, 817, 756, 665, 549. ESIHRMS: Found: m/z
396.1618. Calcd for C23H26NO3S: (M + H)+ 396.1628.
3k: The reaction mixture was chromatographed using 30:1
hexanes/EtOAc to afford 67.2 mg (85%) of the indicated compound
1
after 4 h. H NMR (400 MHz, CDCl3): δ 7.79−7.73 (m, 2H), 7.38−
7.33 (m, 2H), 7.24−7.11 (m, 1H), 6.82−6.72 (m, 3H), 6.26−6.23 (t, J
= 3.0 Hz, 1H), 4.85−4.77 (m, 2H), 4.11−3.89 (m, 2H), [3.79(s),
3.77(s), 3H], 3.59−3.47 (m, 2H), 3.30−3.15 (m, 1H), 2.46 (s, 3H),
[1.70(s), 1.66(s), 3H]; 13C NMR (100 MHz, CDCl3) δ 198.1, 197.9,
159.8, 159.7, 143.8, 142.7, 142.2, 135.3, 135.1, 132.6, 129.8, 129.7,
129.6, 127.9, 119.7, 113.3, 113.2, 112.7, 112.6, 112.1, 105.1, 104.9,
99.4, 99.3, 55.2, 55.1, 52.3, 52.2, 49.8, 49.5, 49.0, 21.6, 19.9, 19.5; IR
(neat, cm−1) 3407, 2926, 1597, 1346, 1162, 1092, 1040, 815, 754, 666,
548. ESIHRMS: Found: m/z 413.1896. Calcd for C23H29N2O3S: (M +
NH4)+ 413.1893.
3l: The reaction mixture was chromatographed using 30:1 hexanes/
EtOAc to afford 73.6 mg (93%) of the indicated compound after 4 h.
1H NMR (400 MHz, CDCl3): δ 7.75−7.73 (d, J = 8.0 Hz, 2H), 7.37−
7.34 (d, J = 8.0 Hz, 2H), 7.25−7.13 (m, 2H), 6.88−6.81 (m, 2H),
6.67−6.64 (t, J = 4.2 Hz, 1H), 4.83−4.75 (m, 2H), 4.11−3.85 (m,
2H), [3.80(s), 3.79(s), 3H], 3.60−3.45 (m, 2H), 3.31−3.14 (m, 1H),
2.45 (s, 3H), [1.67(s), 1.66(s), 3H]; 13C NMR (100 MHz, CDCl3) δ
198.5, 198.3, 156.1, 143.7, 142.8, 142.3, 132.9, 132.8, 129.7, 128.5,
128.0, 127.8, 122.2, 122.0, 120.6, 113.1, 112.9, 103.9, 103.8, 93.4, 93.3,
55.5, 55.4, 52.3, 49.9, 49.8, 49.4, 49.1, 22.6, 21.5, 19.8, 19.5; IR (neat,
cm−1) 3407, 2924, 1595, 1346, 1163, 1095, 1028, 817, 755, 665, 548.
ESIHRMS: Found: m/z 396.1622. Calcd for C23H26NO3S: (M + H)+
396.1628.
3g: The reaction mixture was chromatographed using 30:1
hexanes/EtOAc to afford 71.3 mg (94%) of the indicated compound
after 4 h. 1H NMR (400 MHz, CDCl3): δ 7.77−7.73 (m, 2H), 7.38−
7.32 (m, 2H), 7.18−7.02 (m, 1H), 6.99−6.96 (m, 3H), 6.26−6.21 (m,
1H), 4.84−4.76 (m, 2H), 4.13−3.87 (m, 2H), 3.61−3.46 (m, 2H),
3.30−3.13 (m, 1H), 2.46 (s, 3H), [2.34(s), 2.31(s), 3H], [1.69(s),
1.66(s), 3H]; 13C NMR (100 MHz, CDCl3) δ 198.0, 197.8, 143.8,
143.3, 142.6, 142.2, 138.3, 138.2, 134.8, 133.7, 133.5, 132.7, 132.6,
130.5, 129.8, 129.7, 129.6, 128.9, 128.8, 128.5, 128.4, 128.3, 128.2,
127.9, 127.8, 127.6, 125.4, 124.2, 124.1, 113.2, 104.8, 104.7, 99.4, 99.3,
52.2, 49.8, 49.7, 49.5, 49.0, 21.6, 21.3, 19.8, 19.5; IR (neat, cm−1) 3433,
2923, 2361, 1720, 1345, 1163, 1093, 1037, 816, 755, 666, 548.
ESIHRMS: Found: m/z 380.1674. Calcd for C23H26NO2S: (M + H)+
380.1679.
3m: The reaction mixture was chromatographed using 30:1
hexanes/EtOAc to afford 67.2 mg (79%) of the indicated compound
1
after 4 h. H NMR (400 MHz, CDCl3): δ 7.75−7.72 (d, J = 7.6 Hz,
2H), 7.38−7.34 (m, 2H), 6.80−6.70 (m, 3H), 6.65−6.62 (m, 1H),
4.85−4.76 (m, 2H), 4.09−3.88 (m, 2H), [3.77(s), 3.74(s), 6H], 3.57−
3.44 (m, 2H), 3.30−3.15 (m, 1H), 2.45 (s, 3H), [1.71(s), 1.66(s),
3H]; 13C NMR (100 MHz, CDCl3) δ 198.3, 198.2, 153.5, 150.6,
143.8, 142.9, 142.2, 132.6, 132.5, 129.8, 129.7, 127.8, 127.5, 123.3,
122.9, 113.9, 113.7, 113.2, 112.9, 112.8, 112.2, 104.3, 104.2, 93.5, 93.4,
56.2, 56.1, 55.6, 55.5, 52.3, 52.2, 49.8, 49.4, 48.9, 21.5, 19.9, 19.5; IR
(neat, cm−1) 3415, 2924, 1642, 1382, 1162, 1092, 1043, 811, 707, 665,
549. ESIHRMS: Found: m/z 426.1730. Calcd for C24H28NO4S: (M +
H)+ 426.1734.
3h: The reaction mixture was chromatographed using 30:1
hexanes/EtOAc to afford 71.3 mg (94%) of the indicated compound
1
after 4 h. H NMR (400 MHz, CDCl3): δ 7.76−7.73 (d, J = 8.0 Hz,
2H), 7.38−7.35 (d, J = 8.0 Hz, 2H), 7.18−7.07 (m, 4H), 6.47−6.44
(m, 1H), 4.82−4.76 (m, 2H), 4.09−3.90 (m, 2H), 3.70−3.45 (m, 2H),
3.29−3.16 (m, 1H), 2.46 (s, 3H), [2.29(s), 2.28(s), 3H], [1.67(s),
1.66(s), 3H]; 13C NMR (100 MHz, CDCl3) δ 198.6, 198.5, 143.8,
142.6, 142.2, 135.4, 135.2, 132.6, 132.1, 131.9, 131.7, 130.6, 130.5,
129.7, 127.8, 127.7, 127.4, 127.3, 126.0, 113.3, 113.2, 103.9, 103.6,
96.9, 96.7, 52.2, 49.9, 49.9, 49.5, 49.3, 21.6, 19.9, 19.8, 19.7, 19.5; IR
(neat, cm−1) 3432, 2923, 1598, 1345, 1163, 1093, 1036, 816, 754, 665,
3n: The reaction mixture was chromatographed using 30:1
hexanes/EtOAc to afford 60.7 mg (73%) of the indicated compound
after 4 h. 1H NMR (400 MHz, CDCl3): δ 7.77−7.69 (m, 5H), 7.57 (s,
1H), 7.46−7.41 (m, 2H), 7.37−7.34 (d, J = 7.6 Hz, 2H), 7.30−7.27
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Article
(d, J = 8.8 Hz, 2H), 6.45−6.43 (t, J = 3.2 Hz, 1H), 4.86−4.76 (m, 2H),
4.17−3.92 (m, 2H), 3.64−3.43 (m, 2H), 3.34−3.17 (m, 1H), 2.46 (s,
3H), [1.70(s), 1.67(s), 3H]; 13C NMR (100 MHz, CDCl3) δ 198.5,
198.3, 143.8, 142.5, 142.1, 133.5, 132.7, 131.3, 131.2, 129.7, 128.2,
127.9, 127.7, 127.6, 127.5, 126.3, 126.1, 126.0, 125.9, 124.6, 124.5,
113.3, 105.2, 105.1, 99.7, 99.6, 52.2, 49.8, 49.5, 49.1, 22.6, 21.5, 19.8,
19.6; IR (neat, cm−1) 3400, 2923, 1599, 1382, 1162, 1092, 1038, 816,
715, 666, 548. ESIHRMS: Found: m/z 438.1503. Calcd for
C26H25NNaO2S: (M + Na)+ 438.1498.
3o: The reaction mixture was chromatographed using 30:1
hexanes/EtOAc to afford 29.7 mg (40%) of the indicated compound
after 4 h. 1H NMR (400 MHz, CDCl3): δ 7.76−7.70 (m, 2H), 7.37−
7.33 (m, 2H), 7.18−7.14 (m, 1H), 6.94−6.90 (m, 1H), 6.86−6.85 (d, J
= 3.6 Hz, 1H), 6.51−6.47 (m, 1H), 4.86−4.78 (m, 2H), 4.10−3.87 (m,
2H), 3.64−3.39 (m, 2H), 3.26−3.17 (m, 1H), [2.46(s), 2.45(s), 3H],
[1.72(s), 1.66(s), 3H]; 13C NMR (100 MHz, CDCl3) δ 197.3, 197.2,
143.8, 143.6, 142.3, 142.1, 137.9, 132.7, 131.6, 129.8, 129.7, 127.9,
127.5, 127.4, 126.8, 126.5, 125.7, 125.5, 125.1, 123.3, 113.5, 113.3,
105.3, 105.2, 93.5, 93.4, 52.2, 51.3, 49.8, 49.7, 49.1, 21.6, 19.7, 19.6; IR
(neat, cm−1) 3409, 2925, 1647, 1345, 1162, 1094, 1041, 815, 753, 666,
549. ESIHRMS: Found: m/z 372.1082. Calcd for C20H22NO2S2: (M +
H)+ 372.1086.
ASSOCIATED CONTENT
■
S
* Supporting Information
The detailed experimental procedure and copies of 1H and 13
C
NMR spectra of all compounds. This material is available free
of charge via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
■
Corresponding Author
*E-mail: liangym@lzu.edu.cn.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We thank the NSF (NSF-21072080, NSF-20732002) for
financial support. We acknowledge the National Basic Research
Program of China (973 program), 2010CB833203 and also the
support by the 111 Project.
3s: The reaction mixture was chromatographed using 30:1 hexanes/
EtOAc to afford 28.6 mg (45%) of the indicated compound after 4 h.
1H NMR (400 MHz, CDCl3): δ 7.73−7.70 (d, J = 8.4 Hz, 2H), 7.35−
7.32 (d, J = 8.0 Hz, 2H), 4.76−4.74 (m, 2H), 3.87−3.74 (m, 2H),
3.48−3.43 (m, 1H), 3.34−3.29 (t, J = 7.4 Hz, 1H), 3.13−3.08 (m,
1H), 2.44 (s, 3H), 1.63(s, 9H); 13C NMR (100 MHz, CDCl3) δ 194.6,
143.6, 143.2, 133.0, 129.6, 127.7, 112.5, 100.8, 98.5, 52.1, 49.9, 48.8,
21.5, 20.5, 20.2, 19.4; IR (neat, cm−1) 3403, 2919, 1347, 1164, 1092,
1035, 816, 706, 663, 550. ESIHRMS: Found: m/z 318.1529. Calcd for
C18H24NO2S: (M + H)+ 318.1523.
General Procedure for the Palladium-Catalyzed Suzuki
Reactions of Enyne Carbonates 1. 1,6-Enyne carbonate 1a (88.3
mg, 0.2 mmol), Pd(dba)2 (11.5 mg, 10 mol %), KOAc (39 mg, 0.4
mmol), P(2-furyl)3 (4.6 mg, 10 mol %), PhB(OH)2 (48.8 mg, 0.4
mmol), and DMF (2 mL) were added to a 20 mL tube under an argon
atmosphere. The resulting mixture was stirred at 85 °C. When the
reaction was considered complete as determined by TLC, the reaction
mixture was allowed to cool to room temperature, quenched with a
saturated aqueous solution of ammonium chloride, and extracted with
ethyl acetate. The combined organic extracts were washed with water
and saturated brine, dried over Na2SO4, and filtered. Solvent was
evaporated under reduced pressure. The residue was purified by
chromatography on silica gel using mixtures of hexanes and EtOAc to
afford 3aa (70.9 mg, 80%).
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Characterization Data of Products 3aa, 3ab. 3aa: The reaction
mixture was chromatographed using 30:1 hexanes/EtOAc to afford
1
67.4 mg (76%) of the indicated compound after 4 h. H NMR (400
MHz, CDCl3): δ 7.68−7.65 (d, J = 8.4 Hz, 2H), 7.51−7.48 (d, J = 7.6
Hz, 2H), 7.35−7.30 (m, 2H), 7.29−7.19 (m, 8H), 6.36 (s, 1H), 4.96−
4.92 (t, J = 6.8 Hz, 1H), 4.52−4.47 (m, 1H), 3.29−3.24 (m, 1H),
3.89−3.74 (m, 2H), 2.41 (s, 3H), 1.55(s, 3H), 1.54(s, 3H); 13C NMR
(100 MHz, CDCl3) δ 207.3, 142.9, 137.2, 136.4, 133.8, 133.4, 129.4,
128.7, 128.6, 127.6, 127.5, 127.4, 127.0, 126.5, 106.0, 98.9, 47.1, 44.8,
25.6, 21.5, 17.8; IR (neat, cm−1) 3399, 2920, 1382, 1158, 1093, 1023,
771, 553. ESIHRMS: Found: m/z 444.1987. Calcd for C28H30NO2S:
(M + H)+ 444.1992.
Tetrahedron 1999, 55, 13463. (d) Bohmer, J.; Grigg, R.; Marchbank, J.
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3ab: The reaction mixture was chromatographed using 30:1
hexanes/EtOAc to afford 71.9 mg (69%) of the indicated compound
1
after 4 h. H NMR (400 MHz, CDCl3): δ 7.61−7.58 (d, J = 8.0 Hz,
2H), 7.55−7.52 (d, J = 8.0 Hz, 1H), 7.38−7.24 (m, 6H), 7.22−7.10
(m, 4H), 6.23−6.21 (t, J = 2.4 Hz, 1H), 4.98−4.94 (t, J = 7.0 Hz, 1H),
4.36−4.30 (m, 1H), 4.21−4.16 (m, 1H), 3.90−3.79 (m, 2H), 2.39 (s,
3H), 1.62(s, 3H), 1.59(s, 3H); 13C NMR (100 MHz, CDCl3) δ 204.9,
142.8, 137.4, 136.9, 135.8, 133.4, 132.9, 130.9, 129.4, 129.1, 128.6,
127.5, 127.4, 127.3, 127.2, 123.2, 118.8, 106.2, 97.4, 48.7, 45.2, 25.8,
21.4, 17.9; IR (neat, cm−1) 3398, 2923, 1354, 1164, 1090, 1023, 771,
683, 547. ESIHRMS: Found: m/z 522.1199. Calcd for C28H30BrNO2S:
(M + H)+ 522.1197.
2771
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