An efficient method to construct 2-vinylidenyl cyclobutanone derivatives and its structural determination

Article abstract of DOI:10.1080/15533171003766485

2-Vinylidenyl cyclobutanone derivatives 5 can be readily synthesized from the dialkynyl cyclopropanols 4 through a consecutive process of 1,6-diynes carbocyclization and ring enlargement of cyclopropnaol unit by using AuCl(PPh3)/AgPF6 as catalyst in DCE a

Full text of DOI:10.1080/15533171003766485

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An Efficient Method to Construct 2-vinylidenyl
Cyclobutanone Derivatives and its Structural
Determination
Yu-Xin Zhang a , Lin Guo a , Ya-Hui Wang b , Li-Li Zhu b & Zi-Li Chen b
a School of Chemistry and Environment , Beijing University of Aeronautics and
Astronautics , Beijing, China
b Department of Chemistry , Renmin University of China , Beijing, China
Published online: 10 May 2010.
To cite this article: Yu-Xin Zhang , Lin Guo , Ya-Hui Wang , Li-Li Zhu & Zi-Li Chen (2010) An Efficient Method to Construct
2-vinylidenyl Cyclobutanone Derivatives and its Structural Determination, Synthesis and Reactivity in Inorganic, Metal-
Organic, and Nano-Metal Chemistry, 40:4, 241-245
To link to this article: http://dx.doi.org/10.1080/15533171003766485
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Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 40:241–245, 2010
Copyright © Taylor & Francis Group, LLC
ISSN: 1553-3174 print / 1553-3182 online
DOI: 10.1080/15533171003766485
An Efficient Method to Construct 2-vinylidenyl
Cyclobutanone Derivatives and its Structural Determination
Yu-Xin Zhang,1 Lin Guo,1 Ya-Hui Wang,2 Li-Li Zhu,2 and Zi-Li Chen2
1School of Chemistry and Environment, Beijing University of Aeronautics and Astronautics, Beijing, China
2Department of Chemistry, Renmin University of China, Beijing, China
new method to construct vinylidene substituted cyclobutanone
derivatives from 1, 6-dialkynyl cyclopropanol 4 via gold cataly-
sis. This is the first report, to the best of our knowledge, of a gold
catalyzed one pot, two-step reactions involved with intramolec-
ular carbocyclization of 1, 6-diynes and ring-enlargement of
the cyclopropanol units to construct polycyclic products from
dialkynyl cyclopropanols.
2-Vinylidenyl cyclobutanone derivatives 5 can be readily syn-
thesized from the dialkynyl cyclopropanols 4 through a consecutive
process of 1,6-diynes carbocyclization and ring enlargement of cy-
clopropnaol unit by using AuCl(PPh3)/AgPF6 as catalyst in DCE at
rt. The structure of compound 5a was identified to a 2-vinylidenyl
cyclobutanone by X-ray crystallographic analysis. The unit cell
has monoclinic P2(1)/c symmetry with the cell parameters a =
˚
˚
˚
10.919(2) A, b = 17.508(4) A, c = 7.9219(16) A, and Z = 4.
EXPERIMENTAL
Keywords AuCl(PPh3) catalys, diynes cycloisomerization, vinyli-
denyl cyclobutanone
Reaction Procedures
All reactions were carried out under nitrogen and moni-
tored by thin-layer chromatograph (TLC). AuCl(PPh3) (99%).
AgPF6 and other reagents were obtained commercially and used
without further purification. Flash chromatographic purification
of products was performed on 200–300 mesh silica gel. Thin-
layer chromatography (TLC) was visualized with UV light (254
INTRODUCTION
Transition metals catalyzed carbocyclization of unsaturated
substrates are an efficient method for the construction of
complex cyclic molecules.[1] Among them, cycloisomerization
of 1, 6-diynes has appeared as conceptually and chemically
highly attractive process for the preparation of bi- and tricyclic
aromatic compounds of various structural characteristics and
diversities.[2] However, as compared with the extensive studies
of the metal induced 1,6-enyne cyclization,[3] efficient transfor-
mation involved with carbocyclization of 1,6-diynes remains to
be a less explored topic. Especially for the gold catalyzed 1,6-
diynes cyclization, only a few results have ever been reported
of employing gold complexes in this field.[4]
Cyclobutanone is an important synthetic subunit in organic
synthesis for its unique spatial and electronic properties in con-
junction with the high chemical reactivity.[5] The classical route
to synthesize substituted cyclobutanones usually required te-
dious reaction procedures.[6] Herein, we will report a convenient
1
and 365 nm) or by iodine vapor staining. H and 13C NMR
spectra were recorded in CDCl3 solution on a 400 MHz spec-
trometer.
Our synthetic effort started from the 4-methyl-N, N-di(prop-
2-ynyl)benzene sulfonamide 2 (Scheme 1), which can be read-
ily prepared according to the reported literature procedures.[7]
We have reported the synthesis of 1-alknyl cyclopropanol
and its synthetic applications to construct trisubstituted cross-
conjugated dienone derivatives and 1-alkynyl cyclopropyl t-
butyl carbonate in previous studies.[8] Herein we will prepare 1,
6-dialkynyl cyclopropanol 4a from diynes 2 by using a similar
method.
When compound 2 was treated with 2 eq. of n-BuLi in THF
at −40◦C for 30 min., the in-situ generated lithium alkynilide
reacted with 1-(phenylsulfonyl) cyclopropanol 3 to give 1, 6-
dialkynyl cyclopropanol 4a in 52% yield.
It was found that 4a can be transformed into vinylidenyl
cyclobutanone derivatives 5a in the condition of gold catalyst.
Further optimization upon solvents and catalysts combination
identified the best reaction condition. When 4a was treated with
AuCl(PPh3)/AgPF6 in DCE at rt., 5a was obtained in 60% yield.
The detailed procedures for the preparation of compound 4a and
5a have been provided below.
Received 8 January 2010; accepted 2 February 2010.
The authors gratefully acknowledge a starter grant from the Renmin
University of China and the grant from National Sciences Foundation
of China (No. 20502033).
Address correspondence to Yu-Xin Zhang, School of Chemistry
and Environment, Beijing University of Aeronautics and Astronautics,
Beijing 100191, China. E-mail: zhangyuxin5566@126.com
241

242
Y.-X. ZHANG ET AL.
O
HO
S
O
O
C3H3Br K2CO3
acetone reflux
3
O
S NH2
O
S N
n-BuLi THF -40¡æ
O
1
2
OH
O
O
O
AuCl(PPh3) AgPF6
S N
O
S N
O
C2H4Cl2 rt
5a
4a
SCH. 1. Preparation of the title compound 5a.
Compound 5a was characterized with 1H NMR and 13C NMR
spectral data, the exact structure of which was finally determined
by X-ray crystallography.
To a solution of 20 mg compound 4a in 2 mL dichloroethane
was added 8% AuCl(PPh3)/AgPF6 at room temperature. After 6
hours, the title compound 5a was readily obtained in 60% yield.
Compound 4a:1H NMR δH: 0.71–0.73 (m, 2H), 0.84–0.96(m,
2H), 2.17 (t, J = 2.5Hz 1H), 2.42(s, 1H), 4.12–4.18 (m, 4H),
7.30 (d, J = 8.0 Hz, 2H), 7.69(d, J = 8.0Hz, 2H). 13C NMRδC:
12.4, 13.8, 21.6, 36.4, 36.6, 45.1, 78.1, 85.9, 87.3, 87.8, 127.8,
127.9, 129.6, 129.7, 135.2, 144.1.
Preparation of the Alkynyl Cyclopropanol 4a and Title
Compound 5a
A flame-dried there-necked flask was charged with 1.7 mmol
compound 2 dissolved in 20 mL THF under N2. The flask was
cooled to −40◦C, and 2.67 mL(4.3 mmol) n-BuLi(1.6 M in
hexane) was added dropwise over 10 min, followed by slow
warming to −30◦C and stirring for 1 h, and then 406.8 mg(2.05
mmol) 1-(phenylsulfonyl)cyclopropanol 3 was added in 10 min.
The reaction was kept at −30◦C about 3 h , quenched by aqueous
saturated ammonium chloride, allowed to warm to room tem-
perature. The layers were separated, and the aqueous phase was
extracted with 100 mL three portions of ethyl acetate. The com-
bined organic layers were washed with 100 mL brine, dried over
MgSO4 and filtered. The solvent was removed by rotary evapo-
ration, and the residue was purified by column chromatography
on silica gel to afford compound 4a about 50% yield.
Compound 5a: IR: 800.5 cm−1,1018.4cm−1, 1091.7cm−1
1163.1cm−1,1261.5 cm−1 1344.4 cm−1,1462.0 cm−1
1726.3 cm−1, 2848.9 cm−1, 2916.4 cm−1,2956.9cm−1
,
,
,
.
1H
NMR δH : 2.44(s, 3H), 2.62(t, J = 7.6Hz, 2H), 2.93 (t, J =
7.6Hz, 2H), 3.81–3.84(m, 4H), 5.98–6.02(m, 1H), 6.99(d, J =
10.0Hz, 1H), 7.30 (d, J = 8.2Hz, 2H), 7.68 (d, J = 8.2Hz, 2H).
13C NMRδC: 19.9, 21.5, 43.7, 44.4, 45.0, 124.0, 127.7, 129.8,
129.9, 131.1, 133.4, 141.4, 144.1, 197.9.
Compound 4b: δH:0.82 (dd, J = 8.2 Hz, J = 5.4 Hz, 2 H),
0.96 (dd, J = 7.4 Hz, J = 4.6 Hz , 2 H), 1.97(t, J = 2.7 Hz, 1
H), 2.73(s, 1H), 2.88 (d, J = 2.4Hz, 2H), 2.93 (s, 2H), 3.69(s,
6H). 13C NMR δC: 17.3, 22.7, 23.0, 45.5, 53.1, 56.7, 71.8, 76.3,
78.4, 85.5, 169.2.
TABLE 1
Gold(I)-Catalyzed diynes cycloisomerization
Entry
4
5(X)
Yield(%)
OH
O
O
O
S N
O
S N
O
4a
5a
1
60%
OH
O
O
O
O
O
O
O
O
O
4b
5b
2
58%

EFFICIENT METHOD TO CONSTRUCT 2-VINYLIDENYL CYCLOBUTANONE DERIVATIVES
243
TABLE 2
Crystal data and structure refinement for compound 5a
O
H+
AuCl(PPh3)
AgOTf
O
X
OH
X
CCDC deposit no.
741391
X
Au+
Au
Empirical formula color
Formula weight
C16H17 NO3S white
303.37
4
5
Temperature
Wavelength
113(2) K
0.71073 A
SCH. 2. A plausible mechanism to construct compound 5 from dialkynyl
substrates 4.
˚
Crystal system, space group
Unit cell dimensions
Monoclinic, P2(1)/c
◦
˚
of the cyclopropyl unit to form the desired cyclobutanone
products.[9]
a = 10.919(2) A alpha = 90
˚
b = 17.508(4) A beta =
97.43(3)◦
˚
c = 7.9219(16) A gamma =
X-ray Crystal-structure Analysis of the Title Compound 5a
Crystals suitable for X-ray structure determination were
obtained from the compound 5a by slow evaporation of the
petroleum ether and dichloromethane solvent. A white flat crys-
tal with approximate dimensions of 0.20 × 0.16 × 0.12 mm
was mounted on a Bruker SMART 1000 CCD diffractometer for
data collection. The determination of the unit cell parameters
and data collection were performed at 113(2) K, using graphite
90◦
3
˚
Volume
1501.8(5) A
Z, Calculated density
Absorption coefficient
F(000)
4, 1.342 Mg/m3
0.225 mm−1
640
Crystal size
0.20 × 0.16 × 0.12 mm
Theta range for data collection 2.21 to 25.02◦
˚
Limiting indices
-12<=h<=12,
-20<=k<=20, -9<=l<=6
10010/2636 [R(int) =
0.0341]
99.7 %
Semi-empirical from
equivalents
monochromated MoKα (λ = 0.71073 A) radiation. A total of
10010 reflections with 2636 independent reflections (Rint =
0.0341) were measured in the range of 2.21◦ ≤ θ ≤25.02◦
with an oscillation method. All data were corrected using
SADABS.[10] The structure was solved by direct methods us-
ing the SHELXL-97 program and refined by full matrix least
squares on. F2[11] All non-hydrogen atoms were described
with anisotropic thermal parameters. Hydrogen atoms were
introduced at calculated positions. Molecular graphics were
Reflections collected/unique
Completeness to θ = 25.02
Absorption correction
Max. and min. transmission
Refinement method
0.9735 and 0.9564
Full-matrix least-squares on
F2
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I>2σ(I)]
R indices (all data)
2636/0/191
1.088
TABLE 3
Bond lengths [A] for compound 5a
˚
R1 = 0.0381, ωR2 = 0.0998
S(1)-O(1)
S(1)-O(2)
S(1)-N(1)
S(1)-C(1)
1.4324 (12) C(7)-H(7C)
1.4348 (12) C(8)-C(9)
1.6376 (14) C(8)-H(8A)
1.7610 (17) C(8)-H(8B)
0.9600
1.507 (2)
0.9700
R1 = 0.0458, ωR2 = 0.1043
−3
˚
0.230 and -0.431 e A
Largest diff. peak and hole
0.9700
O(3)-C(16) 1.209 (2)
N(1)-C(12) 1.475 (2)
C(9)-C(13)
C(9)-C(10)
C(10)-C(11)
C(10)-H(10)
C(11)-C(12)
C(11)-H(11)
C(12)-H(12A) 0.9700
C(12)-H(12B) 0.9700
C(13)-C(16)
C(13)-C(14)
C(14)-C(15)
C(14)-H(14A) 0.9700
C(14)-H(14B) 0.9700
C(15)-C(16)
C(15)-H(15A) 0.9700
C(15)-H(15B) 0.9700
1.349 (2)
1.450 (2)
1.332 (2)
0.9300
1.490 (2)
0.9300
Compound 5b: IR: 800.5 cm−1,1016.5 cm−1,1056.9 cm−1
,
,
1101.4 cm−1, 1259.5 cm−1, 1377.2 cm−1,1456.3 cm−1
N(1)-C(8)
C(1)-C(6)
C(1)-C(2)
C(2)-C(3)
C(2)-H(2)
C(3)-C(4)
C(3)-H(3)
C(4)-C(5)
C(4)-C(7)
C(5)-C(6)
C(5)-H(5)
C(6)-H(6)
1.477 (2)
1.392 (2)
1.397 (2)
1.379 (3)
0.9300
1.386 (3)
0.9300
1.400 (2)
1.502 (3)
1.381 (2)
0.9300
1639.5 cm−1,1732.1 cm−1,2850.8 cm−1,2922.2 cm−1,2954.9
cm−1. 1H NMR δH : 2.56(t, J = 6.8Hz, 2H), 2.73–2.76(m, 4H),
2.83(t, J = 7.2Hz, 2H), 3.67(s, 6H), 5.96–6.00(m, 1H), 6.965(dt,
J = 10.0 Hz, J = 1.88 Hz, 1H). 13C NMRδC: 19.7, 43.0, 45.2,
45.7, 52.9, 125.6,131.9, 134.8, 142.5, 170.7, 201.9.
Then, malonate substituted dialkynyl cyclopropanol 4b was
also synthesized from the dialkynyl precursor. It was treated with
Au+ catalyst in the same condition to prepare the corresponding
vinylidene substituted cyclobutanone 5b in 58% yield (Table 1,
entry 2).
1.482 (2)
1.520 (2)
1.557 (3)
A plausible mechanism was than proposed. As shown in
Scheme 2, the terminal alkyne was activated by gold catalyst,
which was then attacked by the second alkynyl group. Then,
in-situ generated vinyl cation triggered the ring enlargement
0.9300
1.512 (3)
C(7)-H(7A) 0.9600
C(7)-H(7B) 0.9600

244
Y.-X. ZHANG ET AL.
TABLE 4
Bond angles (◦) for compound 5a
O(1)-S(1)-O(2)
O(1)-S(1)-N(1)
O(2)-S(1)-N(1)
O(1)-S(1)-C(1)
O(2)-S(1)-C(1)
N(1)-S(1)-C(1)
C(12)-N(1)-C(8)
C(12)-N(1)-S(1)
C(8)-N(1)-S(1)
C(6)-C(1)-C(2)
C(6)-C(1)-S(1)
C(2)-C(1)-S(1)
C(3)-C(2)-C(1)
C(3)-C(2)-H(2)
C(1)-C(2)-H(2)
C(2)-C(3)-C(4)
C(2)-C(3)-H(3)
C(4)-C(3)-H(3)
C(3)-C(4)-C(5)
C(3)-C(4)-C(7)
C(5)-C(4)-C(7)
C(6)-C(5)-C(4)
C(6)-C(5)-H(5)
C(4)-C(5)-H(5)
C(5)-C(6)-C(1)
C(5)-C(6)-H(6)
C(1)-C(6)-H(6)
C(4)-C(7)-H(7A)
C(4)-C(7)-H(7B)
119.82 (8)
106.06 (8)
106.40 (7)
107.94 (8)
108.17 (8)
107.95 (8)
114.15 (14)
116.11 (11)
117.91 (11)
120.55 (16)
120.09 (12)
119.35 (14)
118.56 (18)
120.7
N(1)-C(8)-H(8B)
C(9)-C(8)-H(8B)
H(8A)-C(8)-H(8B)
C(13)-C(9)-C(10)
C(13)-C(9)-C(8)
110.0
110.0
108.4
122.09 (16)
121.77 (16)
116.07 (14)
121.81 (16)
119.1
119.1
122.96 (16)
118.5
118.5
110.30 (13)
109.6
109.6
109.6
C(10)-C(9)-C(8)
C(11)-C(10)-C(9)
C(11)-C(10)-H(10)
C(9)-C(10)-
C(10)-C(11)-C(12)
C(10)-C(11)-H(11)
C(12)-C(11)-H(11)
N(1)-C(12)-C(11)
N(1)-C(12)-H(12A)
C(11)-C(12)-H(12A)
N(1)-C(12)-H(12B)
C(11)-C(12)-H(12B)
H(12A)-C(12)-H(12B) 108.1
C(9)-C(13)-C(16)
C(9)-C(13)-C(14)
C(16)-C(13)-C(14)
C(13)-C(14)-C(15)
C(13)-C(14)-H(14A)
C(15)-C(14)-H(14A)
C(13)-C(14)-H(14B)
C(15)-C(14)-H(14B)
120.7
122.32 (16)
118.8
109.6
118.8
117.96 (16)
121.30 (16)
120.73 (17)
121.11 (17)
119.4
119.4
119.46(15)
120.3
131.79 (17)
136.94 (16)
91.27 (14)
88.44 (14)
113.9
113.9
113.9
113.9
120.3
109.5
109.5
H(14A)-C(14)-H(14B) 111.1
C(16)-C(15)-C(14)
C(16)-C(15)-H(15A)
C(14)-C(15)-H(15A)
C(16)-C(15)-H(15B)
C(14)-C(15)-H(15B)
88.75 (13)
113.9
113.9
113.9
113.9
H(7A)-C(7)-H(7B) 109.5
C(4)-C(7)-H(7C) 109.5
H(7A)-C(7)-H(7C) 109.5
H(7B)-C(7)-H(7C) 109.5
H(15A)-C(15)-H(15B) 111.1
N(1)-C(8)-C(9)
N(1)-C(8)-H(8A)
C(9)-C(8)-H(8A)
108.40 (14)
110.0
110.0
O(3)-C(16)-C(13)
O(3)-C(16)-C(15)
C(13)-C(16)-C(15)
134.76 (18)
133.68(17)
91.54(15)
performed by SHELXL-97.[11] Full crystallographic details
have been deposited with the Cambridge Crystallographic Data
Center and allocated the deposition number CCDC-741391.
Further details of the structure analyses are given in Table 2.
Bond lengths and angles are given in Tables 3 and 4, respec-
tively.
˚
˚
A and 1.332(2) A, respectively, which means they are both
double bonds. Heterocyclic cyclohexene unit is connected with
cyclobutanone unit through the Z-configuration C9–C13 double
bond.
The carbonyl group locates at C16 carbon, which was found
to have a strong signal at 1726 cm−1 in the IR spectrum, and
at 197.9 ppm in the 13C-NMR spectrum. Toluenesulfonyl group
attached to nitrogen atom with a dihedral angle of 107.95(8)◦
with heterocyclic cyclohexene. Meanwhile, cyclobutanone and
heterocyclic cyclohexene units are almost in the same plane.
A sketch of the intermolecular π-stacking between two
phenyl groups is shown in Figure 2. The unit cell contains four
molecules, and has P2(1)/c symmetry with unit cell parameters
RESULTS AND DISCUSSION
An ORTEP drawing of compound 5a is shown in Fig-
ure 1. Single crystal X-ray diffraction analysis reveals that
the molecular structure of (E)-2-(1-tosyl-1, 2-dihydro pyridin-
3(6H)-ylidene) cyclobutanone 5a (Figure 1) is essentially as
expected. The C9–C13 and C10–C11 contact lengths are 1.349(2)

EFFICIENT METHOD TO CONSTRUCT 2-VINYLIDENYL CYCLOBUTANONE DERIVATIVES
245
data request@ccdc.cam.ac.uk, or by contacting The Cambridge
Crystallographic Data Center, 12 Union Road, Cambridge CB2
1EZ, UK; fax: +44-(0)-1223-336033.
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FIG. 2. Three-dimensional molecular-packing diagram of 5a.
˚
˚
˚
a = 10.919(2) A, b = 17.508(4) A, c = 7.9219(16) A, α =
◦
◦
◦
3
˚
90 , β = 97.43(3) , γ = 90 , V =1501.8(5) A , Dx=.1.342
g.cm-3, Z = 4, T=113(2) K.
SUPPLEMENTARY MATERIAL
CCDC 741391 contains the supplementary crystallographic
data for this paper. These data can be obtained free of
charge via http://www.ccdc.cam.ac.uk/data/cif, by e-mailing
11. Sheldrick, G.M. SHELXTL97, Version 5.10., 1997, Bruker AXS,Inc.,
Madison, WI.