An organophosphorus-mediated cross-Rauhut-Currier/Wittig domino reaction for the efficient synthesis of trisubstituted cyclopentenes

Article abstract of DOI:10.1039/d1ob00150g

An efficient organophosphorus-mediated cross-Rauhut-Currier/Wittig domino reaction of vinyl ketones with chalcones has been developed for the synthesis of trisubstituted cyclopentenes. The new synthetic method has the advantages of mild reaction condition

Full text of DOI:10.1039/d1ob00150g

Organic &
Biomolecular Chemistry
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An organophosphorus-mediated
cross-Rauhut–Currier/Wittig domino reaction
for the efficient synthesis of trisubstituted
Cite this: Org. Biomol. Chem., 2021,
19, 2487
cyclopentenes†
a
Ya-Qiong Li,a,b Guo-Dong Xua and Zhi-Zhen Huang
*
Received 26th January 2021,
Accepted 24th February 2021
An efficient organophosphorus-mediated cross-Rauhut–Currier/Wittig domino reaction of vinyl ketones
with chalcones has been developed for the synthesis of trisubstituted cyclopentenes. The new synthetic
method has the advantages of mild reaction conditions, high efficiency, environmental friendliness and
satisfactory yields.
DOI: 10.1039/d1ob00150g
rsc.li/obc
Currier reaction in this domino reaction is limited to homodi-
merization of α,β-unsaturated ketones. In our previous work
Introduction
As a graceful strategy for the efficient formation of a carbon– on the MBH-type of reaction of α,β-unsaturated ketones with
carbon bond, the Rauhut–Currier reaction, which creates a allylic acetates, we found that the addition of a proton acid
new carbon–carbon bond between the α-position of an acti- could decrease homodimers of the α,β-unsaturated ketones.8
vated alkene and the β-position of a second activated alkene, Thus, we envisioned that an α,β-unsaturated ketone could
has drawn much attention.1 The domino reaction can form undergo a nucleophilic addition with a tertiary phosphine
two or more chemical bonds in a single reaction with the (PR3), followed by a protonation to form keto intermediate III
advantages of step-efficiency and environmental friendliness. (Scheme 1, eqn (2)). Keto intermediate III could change into
Because a Rauhut–Currier intermediate contains both nucleo- enol intermediate IV by a keto–enol tautomerism. The enol in
philic and electrophilic atoms, the Rauhut–Currier reaction IV may nucleophilically attack the β-carbon of another
can be readily incorporated into a domino process.2 After the α,β-unsaturated ketone to generate zwitterion intermediate V.
twentieth century, many domino reactions initiated by Through intramolecular proton exchange, V could change into
Rauhut–Currier reactions have been developed for the for- phosphonium ylide VI. Successively, the intramolecular Wittig
mation of multiple carbon–carbon bonds in a single reaction, reaction of ylide VI may lead to multisubstituted cyclopentene.
such as cross-Rauhut–Currier/Michael,3 cross-Rauhut–Currier/ Multisubstituted cyclopentenes as important intermediates
aldol,4 cross-Rauhut–Currier/Michael/SN2,5 cross-Rauhut– have been widely applied in organic synthesis.9
Currier/aldol/allylic SN,6 and Rauhut–Currier/Michael/Wittig7
domino reactions.
Moreover, the Wittig reaction is one of the most important
processes for the formation of carbon–carbon double bonds.
Nevertheless, only one report discloses a domino reaction com-
bining the Rauhut–Currier reaction with the Wittig reaction.
In 2006, Schaus et al. developed a Rauhut–Currier/Michael/
Wittig domino reaction of 1,4-dien-3-ones I to give bicyclo
[3.2.1]octenones II (Scheme 1, eqn (1)).7 However, the Rauhut–
aDepartment of Chemistry, Zhejiang University, Hangzhou 310058, P.R. China.
E-mail: huangzhizhen@zju.edu.cn
bSchool of Chemistry and Chemical Engineering, Yangtze Normal University,
Chongqing, 408100, P.R. China
†Electronic supplementary information (ESI) available. CCDC 2022239. For ESI
and crystallographic data in CIF or other electronic format see DOI: 10.1039/
d1ob00150g
Scheme 1 Domino reactions combining the Rauhut–Currier reaction
with the Wittig reaction.
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dimer.8 Thus, it can be concluded that the optimized reaction
should be performed at 100 °C in the presence of (n-Bu)3P
Results and discussion
Initially, vinyl ketone 1a and chalcone 2a were chosen as (100 mol%) and HOAc (2.0 equiv.) in 1,4-dioxane under
model substrates to explore and optimize their cross-Rauhut– nitrogen.
Currier/Wittig domino reaction. When the reaction was per-
Under the optimized conditions, we found that various aryl
formed at 100 °C using (n-Bu)3P (100 mol%) as a Lewis base vinyl ketones 1a–e, which carried either electron-donating or
catalyst and PivOH as a proton acid in dioxane under a nitro- electron-withdrawing groups on the benzene ring (in 1a–e),
gen atmosphere, we were pleased to find that the expected tri- were able to undergo the cross-Rauhut–Currier/Wittig domino
substituted cyclopentene 3aa was obtained in 56% yield reaction smoothly with chalcone 2a to give the desired trisub-
(entry 1, Table 1). Then, other tertiary phosphines were stituted cyclopentenes 3aa–ea in satisfactory yields (Scheme 2).
screened, but none of them led to better yields for 3aa The structure of trisubstituted cyclopentene 3da was further
1
(compare entries 2–5 with entry 1, Table 1). Other carboxylic determined by single-crystal X-ray diffraction besides H NMR
acids besides PivOH were examined in the domino reaction, and 13C NMR spectroscopy and HRMS (Fig. 1).10 However,
and HOAc proved to be the most efficient among them (entries when 4-nitrophenyl vinyl ketone was employed, no expected
6–8, Table 1; also see the ESI†). Increasing or decreasing the cycloaddition product was obtained. Then, various chalcones
amount of HOAc led to lower yields of 3aa (compare entries 9 2b–h were examined in the cross-Rauhut–Currier/Wittig
and 10 with entry 7, Table 1). Switching the solvent from domino reaction. The experimental results demonstrated that
dioxane to toluene, dimethyl ether or acetonitrile gave lower or chalcones 2b–h bearing either electron-donating or electron-
no yield of 3aa (compare entries 11–13 with entry 7, Table 1). withdrawing groups on the phenyl rings were also able to
No matter whether the temperature was increased or undergo the domino reaction expediently with vinyl ketone 1a,
decreased, lower yields of 3aa were obtained. It’s noteworthy affording the desired trisubstituted cyclopentenes 3ab–ah in
that in the absence of HOAc, only a dimer by the homo-
Rauhut–Currier reaction of 1a and a cycloaddition product by
the homo-Rauhut–Currier/Wittig domino reaction of 1a were
obtained; no desired product 3aa was isolated (entry 16; also
see the ESI†). The experimental result suggests again that the
proton acid could avoid generating a large amount of enolic
anion adducts of vinyl ketone 1a with (n-Bu)3P, which could
react readily with another vinyl ketone 1a to give its homo-
Table 1 Optimization of the cross-Rauhut–Currier/Wittig domino
reaction of vinyl ketone 1a with chalcone 2a a
Entry
R3P
Carboxylic acid
Solvent
Yieldb (%)
1
2
3
4
5
6
7
8
(n-Bu)3P
Me3P
(t-Bu)3P
Cy3P
PivOH
PivOH
PivOH
PivOH
PivOH
BzOH
HOAc
p-NO2BzOH
HOAc
HOAc
HOAc
HOAc
HOAc
HOAc
HOAc
—
Dioxane
Dioxane
Dioxane
Dioxane
Dioxane
Dioxane
Dioxane
Dioxane
Dioxane
Dioxane
Toluene
DME
56
29
0
Trace
Trace
40
83
0
61
50
76
0
Ph3P
(n-Bu)3P
(n-Bu)3P
(n-Bu)3P
(n-Bu)3P
(n-Bu)3P
(n-Bu)3P
(n-Bu)3P
(n-Bu)3P
(n-Bu)3P
(n-Bu)3P
(n-Bu)3P
9c
10d
11
12
13
14e
15f
16
CH3CN
Dioxane
Dioxane
Dioxane
0
47
66
0
a The mixture of 1a (0.1 mmol), 2a (0.2 mmol), phosphine (100 mol%),
and acid (2.0 equiv.) was stirred in solvent (2 mL) at 100 °C for 48 h
under N2 (1 atm). b Isolated yield. c 1.0 equiv. HOAc. d 3.0 equiv. HOAc.
e 90 °C. f 110 °C.
Scheme 2 The cross-Rauhut–Currier/Wittig domino reaction of vinyl
ketones 1 with α,β-unsaturated ketones 2.
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the optimized conditions, the reaction proceeded smoothly as
well, affording the desired product 3aa (0.75 mmol) in 75%
yield.
Conclusions
In conclusion, we have developed a new cross-Rauhut–Currier/
Wittig domino reaction of vinyl ketones 1 with chalcones 2
mediated by (n-Bu)3P (100 mol%) in the presence of HOAc,
affording the desired trisubstituted cyclopentenes 3. The cross-
Rauhut–Currier/Wittig domino reaction is compatible with
various functional groups to afford a range of trisubstituted
cyclopentenes in moderate to good yields. Organophosphorus
in different phases of the domino reaction may not only serve
as a nucleophile but also stabilize an α-carbanion to perform
the cross-Rauhut–Currier reaction and the successive Wittig
reaction, respectively. The new synthetic method for trisubsti-
tuted cyclopentenes also has the advantages of mild reaction
conditions, high efficiency and environmental friendliness,
which make it possible to apply the method in organic syn-
thesis and the synthesis of related natural products.
Fig. 1 X-ray structure of trisubstituted cyclopentene 3da.
yields of 69–86%. The domino reaction tolerated a range of
functional groups on the benzene ring in chalcones 2b–h,
such as fluoro, chloro, bromo, trifluoromethyl, and methyl
groups. Moreover, when β-methyl-α,β-unsaturated ketone 2i
was employed in the domino reaction with vinyl ketone 1a, the
desired product 3ai was also obtained, albeit in a lower yield.
The domino reaction has excellent diastereoselectivity to give
trans-cyclopentenes 3, and no corresponding cis-stereoisomer
was obtained.
In the absence of chalcone 2, vinyl ketone 1a underwent a
homo-Rauhut–Currier/Wittig domino reaction to give the
cycloaddition product 4a in an 85% yield under the optimized
conditions (Scheme 3). The naphthyl group instead of the
benzene group in aryl vinyl ketone 1f also led to the dimer of
4f in a good yield.
From the perspective of the mechanism for the cross-
Rauhut–Currier/Wittig domino reaction, we successfully uti-
lized the organophosphorus properties that the neutral phos-
phorus can serve as a nucleophile and the cationic phos-
phorus can stabilize an α-carbanion to perform the cross-
Rauhut–Currier reaction and the successive Wittig reaction,
respectively.
In order to demonstrate the practicality of this method-
ology, we performed the cross-Rauhut–Currier/Wittig domino
reaction at a larger scale (Scheme 4). When vinyl ketone 1a
(1.0 mmol) and chalcone 2a (2.0 mmol) were employed under
Experimental
General procedure and characterization data
The general procedure for the cross-Rauhut–Currier/Wittig
domino reaction of vinyl ketone 1 with α,β-unsaturated ketone
2 is as follows.
To a solution of vinyl ketone 1 (0.1 mmol), α,β-unsaturated
ketone 2 (0.2 mmol), and HOAc (0.2 mmol) in dioxane
(2.0 mL) was added (n-Bu)3P (20.2 mg, 0.1 mmol, 100 mol%).
The reaction mixture was stirred at 100 °C for 48 h under nitro-
gen. Then, the solvent was evaporated under reduced pressure.
The residue was purified by column chromatography (silica
gel; ethyl acetate/petroleum ether = 1/100 as the eluent) to give
the desired trisubstituted cyclopentene 3.
(3,5-Diphenylcyclopent-2-en-1-yl)(4-tolyl)methanone (3aa).
White solid (28.1 mg, 83% yield); mp: 127–128 °C; 1H NMR
(400 MHz, CDCl3), δ (ppm): 7.85 (d, J = 8.0 Hz, 2H, Ar),
7.47–7.44 (m, 2H, Ar), 7.34–7.19 (m, 10H, Ar), 6.17 (q, J = 2.1
Hz, 1H, CHCHvC), 4.72–4.69 (m, 1H, CHCHvC), 4.23–4.18
(m, 1H, CHCH2), 3.45–3.39 (m, 1H, CHCHH), 3.04–2.97 (m,
1H, CHCHH), 2.40 (s, 3H, CH3); 13C NMR (100 MHz, CDCl3), δ
(ppm): 198.7, 146.2, 144.2, 144.0, 135.5, 133.9, 129.3, 128.9,
128.7, 128.4, 127.8, 127.3, 126.5, 126.0, 123.1, 63.3, 44.9, 41.9,
21.7; HR-MS (EI-TOF) (M+) calculated for C25H22O 338.1671,
found 338.1672.
Scheme 3 The homo-Rauhut–Currier/Wittig domino reaction of vinyl
ketones 1.
(3,5-Diphenylcyclopent-2-en-1-yl)(4-methoxyphenyl)metha-
none (3ba). White solid (25.1 mg, 71% yield); mp: 175–176 °C;
1H NMR (400 MHz, CDCl3), δ (ppm): 7.95–7.91 (m, 2H, Ar),
7.47–7.45 (m, 2H, Ar), 7.34–7.20 (m, 8H, Ar), 6.92–6.89 (m, 2H,
Ar), 6.17 (q, J = 2.0 Hz, 1H, CHCHvC), 4.71–4.67 (m, 1H,
CHCHvC), 4.19 (dt, J = 8.8, 6.0 Hz, 1H, CHCH2), 3.86 (s, 3H,
OCH3), 3.43 (ddt, J = 16.4, 9.2, 2.2 Hz, 1H, CHCHH), 3.01 (ddt,
Scheme 4 The upscaling reaction.
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J = 16.0, 5.6, 2.0 Hz, 1H, CHCHH); 13C NMR (100 MHz, CDCl3), 6.97 (t, J = 8.8 Hz, 2H, Ar), 6.16 (q, J = 2.0 Hz, 1H, CHCHvC),
δ (ppm): 197.7, 163.6, 146.2, 144.2, 135.5, 131.0, 129.4, 128.7, 4.67–4.63 (m, 1H, CHCHvC), 4.22–4.17 (m, 1H, CHCH2),
128.4, 127.8, 127.3, 126.5, 126.0, 123.2, 113.8, 63.1, 55.5, 45.1, 3.45–3.37 (m, 1H, CHCHH), 2.99–2.92 (m, 1H, CHCHH), 2.40
41.9; HR-MS (EI-TOF) (M+) calculated for C25H22O2 354.1620, (s, 3H, CH3); 13C NMR (100 MHz, CDCl3), δ (ppm): 198.5, 161.6
found 354.1614.
(d, J = 242.8 Hz), 144.2, 144.1, 141.7 (d, J = 3.0 Hz), 135.4,
(3,5-Diphenylcyclopent-2-en-1-yl)(4-fluorophenyl)methanone 133.9, 129.4, 128.8, 128.7 (d, J = 7.9 Hz), 128.4, 127.9, 125.9,
(3ca). White solid (25.0 mg, 73% yield); mp: 114–115 °C; 1H 122.9, 115.4 (d, J = 21.0 Hz), 63.4, 44.1, 41.9, 21.7; HR-MS
NMR (400 MHz, CDCl3), δ (ppm): 7.97–7.94 (m, 2H, Ar), (EI-TOF) (M+) calculated for C25H21FO 356.1576, found 356.1578.
7.48–7.46 (m, 2H, Ar), 7.35–7.20 (m, 8H, Ar), 7.13–7.07 (m, 2H,
(5-(3-Chlorophenyl)-3-phenylcyclopent-2-en-1-yl)(4-tolyl)-
Ar), 6.16 (q, J = 2.0 Hz, 1H, CHCHvC), 4.70–4.67 (m, 1H, methanone (3ad). White solid (29.0 mg, 78% yield); mp:
1
CHCHvC), 4.18–4.13 (m, 1H, CHCH2), 3.47–3.39 (m, 1H, 105–106 °C; H NMR (400 MHz, CDCl3), δ (ppm): 7.87 (d, J =
CHCHH), 3.05–2.99 (m, 1H, CHCHH); 13C NMR (100 MHz, 8.0 Hz, 2H, Ar), 7.46–7.44 (m, 2H, Ar), 7.34–7.19 (m, 9H, Ar),
CDCl3), δ (ppm): 197.7, 165.8 (d, J = 253.6 Hz), 145.9, 144.6, 6.17 (q, J = 2.0 Hz, 1H, CHCHvC), 4.69–4.66 (m, 1H,
135.3, 132.8 (d, J = 3.1 Hz), 131.3 (d, J = 9.2 Hz), 128.7, 128.4, CHCHvC), 4.22 (dt, J = 8.8, 6.0 Hz, 1H, CHCH2), 3.42 (ddt, J =
127.9, 127.2, 126.6, 126.0, 122.4, 115.7 (d, J = 21.8 Hz), 63.3, 16.0, 8.8, 2.2 Hz, 1H, CHCHH), 2.97 (ddt, J = 16.4, 6.0, 2.2 Hz,
45.2, 41.9; HR-MS (EI-TOF) (M+) calculated for C24H19FO 1H, CHCHH), 2.42 (s, 3H, CH3); 13C NMR (100 MHz, CDCl3), δ
342.1420, found 342.1423.
(ppm): 198.2, 148.2, 144.2, 144.1, 135.2, 134.4, 133.8, 129.9,
(4-Chlorophenyl)(3,5-diphenylcyclopent-2-en-1-yl)methanone 129.4, 128.8, 128.4, 127.9, 127.3, 126.7, 126.0, 125.6, 122.8,
(3da). White solid (24.7 mg, 69% yield); mp: 121–122 °C; 1H 63.1, 44.3, 41.7, 21.7; HR-MS (EI-TOF) (M+) calculated for
NMR (400 MHz, CDCl3), δ (ppm): 7.88–7.85 (m, 2H, Ar), C25H21ClO 372.1281, found 372.1282.
7.48–7.21 (m, 12H, Ar), 6.14 (q, J = 2.1 Hz, 1H, CHCHvC),
(5-(3-Bromophenyl)-3-phenylcyclopent-2-en-1-yl)(4-tolyl)-
4.69–4.66 (m, 1H, CHCHvC), 4.14 (dt, J = 9.2, 5.6 Hz, 1H, methanone (3ae). White solid (35.9 mg, 86% yield); mp:
1
CHCH2), 3.43 (ddt, J = 16.0, 9.2, 2.2 Hz, 1H, CHCHH), 3.02 121–122 °C; H NMR (400 MHz, CDCl3), δ (ppm): 7.86 (d, J =
(ddt, J = 16.0, 5.6, 2.4 Hz, 1H, CHCHH); 13C NMR (100 MHz, 8.0 Hz, 2H, Ar), 7.48–7.43 (m, 3H, Ar), 7.36–7.24 (m, 7H, Ar),
CDCl3), δ (ppm): 198.1, 145.8, 144.7, 139.6, 135.3, 134.7, 130.1, 7.15 (t, J = 7.8 Hz, 1H, Ar), 6.16 (q, J = 2.0 Hz, 1H, CHCHvC),
128.9, 128.8, 128.5, 128.0, 127.2, 126.7, 126.0, 122.3, 63.4, 45.1, 4.68–4.65 (m, 1H, CHCHvC), 4.20 (dt, J = 9.2, 5.6 Hz, 1H,
41.9; HR-MS (EI-TOF) (M+) calculated for C24H19ClO 358.1124, CHCH2), 3.42 (ddt, J = 16.4, 9.2, 2.2 Hz, 1H, CHCHH), 2.96
found 358.1121.
(ddt, J = 16.0, 5.8, 2.0 Hz, 1H, CHCHH), 2.41 (s, 3H, CH3); 13C
(4-Bromophenyl)(3,5-diphenylcyclopent-2-en-1-yl)methanone NMR (100 MHz, CDCl3), δ (ppm): 198.1, 148.5, 144.2, 144.0,
(3ea). White solid (32.2 mg, 80% yield); mp: 131–132 °C; 1H 135.2, 133.7, 130.3, 129.6, 129.4, 128.9, 128.4, 128.0, 126.1,
NMR (400 MHz, CDCl3), δ (ppm): 7.80–7.77 (m, 2H, Ar), 126.0, 122.8, 122.7, 63.2, 44.2, 41.7, 21.7; HR-MS (EI-TOF) (M+)
7.59–7.56 (m, 2H, Ar), 7.47–7.45 (m, 2H, Ar), 7.33–7.22 (m, 8H, calculated for C25H21BrO 416.0776, found 416.0777.
Ar), 6.14 (q, J = 2.1 Hz, 1H, CHCHvC), 4.68–4.65 (m, 1H,
(5-Phenyl-3-(4-tolyl)cyclopent-2-en-1-yl)(4-tolyl)methanone
CHCHvC), 4.14 (dt, J = 9.2, 5.6 Hz, 1H, CHCH2), 3.43 (ddt, J = (3af). White solid (24.3 mg, 69% yield); mp: 111–112 °C; 1H
15.6, 8.8, 2.2 Hz, 1H, CHCHH), 3.02 (ddt, J = 16.4, 5.6, 2.0 Hz, NMR (400 MHz, CDCl3), δ (ppm): 7.85 (d, J = 8.0 Hz, 2H, Ar),
1H, CHCHH); 13C NMR (100 MHz, CDCl3), δ (ppm): 198.3, 7.36–7.21 (m, 9H, Ar), 7.12 (d, J = 8.0 Hz, 2H, Ar), 6.11–6.10 (m,
145.8, 144.7, 135.3, 135.1, 131.9, 130.2, 128.8, 128.5, 128.4, 1H, CHCHvC), 4.69–4.68 (m, 1H, CHCHvC), 4.22–4.17 (m,
128.0, 127.2, 126.7, 126.0, 122.2, 63.4, 45.1, 41.9; HR-MS 1H, CHCH2), 3.43–3.37 (m, 1H, CHCHH), 3.01–2.96 (m, 1H,
(EI-TOF) (M+) calculated for C24H19BrO 402.0619, found CHCHH), 2.40 (s, 3H, COArCH3), 2.33 (s, 3H, CH3); 13C NMR
402.0618.
(100 MHz, CDCl3), δ (ppm): 198.8, 146.3, 144.1, 143.9, 137.7,
(3-Phenyl-5-(3-tolyl)cyclopent-2-en-1-yl)(4-tolyl)methanone 134.0, 132.7, 129.3, 129.1, 128.9, 128.7, 127.2, 126.4, 125.9,
(3ab). White solid (25.0 mg, 71% yield); mp: 103–104 °C; 1H 122.0, 63.3, 44.8, 41.9, 21.6, 21.2; HR-MS (EI-TOF) (M+) calcu-
NMR (400 MHz, CDCl3), δ (ppm): 7.86 (d, J = 8.4 Hz, 2H, Ar), lated for C26H24O 352.1827, found 352.1831.
7.47–7.45 (m, 2H, Ar), 7.34–7.02 (m, 9H, Ar), 6.17 (q, J = 2.1 Hz,
(3-(4-Chlorophenyl)-5-phenylcyclopent-2-en-1-yl)(4-tolyl)-
1H, CHCHvC), 4.71–4.69 (m, 1H, CHCHvC), 4.17 (dt, J = 9.2, methanone (3ag). White solid (28.3 mg, 76% yield); mp:
1
5.6 Hz, 1H, CHCH2), 3.41 (ddt, J = 16.4, 9.2, 2.2 Hz, 1H, 147–148 °C; H NMR (400 MHz, CDCl3), δ (ppm): 7.83 (d, J =
CHCHH), 3.00 (ddt, J = 16.4, 5.6, 2.0 Hz, 1H, CHCHH), 2.41 (s, 8.4 Hz, 2H, Ar), 7.38–7.22 (m, 11H, Ar), 6.16 (q, J = 2.0 Hz, 1H,
3H, p-CH3), 2.32 (s, 3H, m-CH3); 13C NMR (100 MHz, CDCl3), δ CHCHvC), 4.72–4.70 (m, 1H, CHCHvC), 4.18 (dt, J = 8.8, 6.0
(ppm): 198.8, 146.1, 144.2, 143.9, 138.3, 135.5, 133.9, 129.3, Hz, 1H, CHCH2), 3.38 (ddt, J = 16.0, 9.2, 2.2 Hz, 1H, CHCHH),
128.9, 128.6, 128.4, 128.0, 127.8, 127.2, 126.0, 124.2, 123.1, 2.97 (ddt, J = 16.4, 6.0, 2.0 Hz, 1H, CHCHH), 2.40 (s, 3H, CH3);
63.4, 44.7, 41.9, 21.6, 21.5; HR-MS (EI-TOF) (M+) calculated for 13C NMR (100 MHz, CDCl3), δ (ppm): 198.6, 145.9, 144.1,
C26H24O 352.1827, found 352.1827.
143.1, 133.9, 133.8, 133.5, 129.4, 128.9, 128.7, 128.6, 127.2,
(5-(4-Fluorophenyl)-3-phenylcyclopent-2-en-1-yl)(4-tolyl)- 127.1, 126.6, 123.7, 63.2, 45.0, 41.9, 21.7; HR-MS (EI-TOF) (M+)
methanone (3ac). White solid (29.5 mg, 83% yield); mp: calculated for C25H21ClO 372.1281, found 372.1279.
1
151–152 °C; H NMR (400 MHz, CDCl3), δ (ppm): 7.85 (d, J =
(5-Phenyl-3-(4-(trifluoromethyl)phenyl)cyclopent-2-en-1-yl)-
8.0 Hz, 2H, Ar), 7.46–7.44 (m, 2H, Ar), 7.33–7.23 (m, 7H, Ar), (4-tolyl)methanone (3ah). White solid (28.8 mg, 71% yield);
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Paper
mp: 73–74 °C; 1H NMR (400 MHz, CDCl3), δ (ppm): 7.84 (d, J = (100 MHz, CDCl3), δ (ppm): 200.2, 145.3, 135.6, 134.0, 133.4,
8.0 Hz, 2H, Ar), 7.59–7.53 (m, 4H, Ar), 7.32–7.23 (m, 7H, Ar), 133.2, 132.9, 132.6, 130.2, 129.6, 128.6, 128.5, 128.2, 127.8,
6.29 (q, J = 2.0 Hz, 1H, CHCHvC), 4.76–4.74 (m, 1H, 127.7, 127.6, 126.8, 126.2, 125.9, 124.8, 124.6, 124.5, 124.2,
CHCHvC), 4.19 (dt, J = 9.2, 5.6 Hz, 1H, CHCH2), 3.43 (ddt, J = 54.7, 33.1, 26.6; HR-MS (EI-TOF) (M+) calculated for C26H20O
16.4, 9.2, 2.2 Hz, 1H, CHCHH), 3.01 (ddt, J = 16.4, 6.0, 2.0 Hz, 348.1514, found 348.1514.
1H, CHCHH), 2.41 (s, 3H, CH3); 13C NMR (100 MHz, CDCl3), δ
(ppm): 198.5, 145.7, 144.2, 143.1, 138.8, 133.7, 129.4, 128.9,
128.8, 127.2, 126.6, 126.2, 125.7, 125.4 (q, J = 3.8 Hz), 63.2,
Conflicts of interest
45.0, 41.8, 21.7; HR-MS (EI-TOF) (M+) calculated for C26H21F3O
406.1544, found 406.1551.
There are no conflicts to declare.
(5-Methyl-3-(4-tolyl)cyclopent-2-en-1-yl)(4-tolyl)methanone
(3ai). White solid (15.7 mg, 54% yield); mp: 78–79 °C; 1H NMR
(400 MHz, CDCl3), δ (ppm): 7.94 (d, J = 8.0 Hz, 2H, Ar),
7.31–7.28 (m, 4H, Ar), 7.10 (d, J = 8.0 Hz, 2H, Ar), 6.01 (d, J =
Acknowledgements
2.0 Hz, 1H, CHCHvC), 4.21–4.19 (m, 1H, CHCHvC), The financial support from the National Natural Science
3.13–2.98 (m, 2H, CH3CHCH2), 2.43–2.38 (m, 4H, CH3CHCH2 Foundation of China (No. 21372195) is gratefully
and COArCH3), 2.32 (s, 3H, ArCH3), 1.22 (d, J = 6.8 Hz, 3H, acknowledged.
CH3CHCH2); 13C NMR (100 MHz, CDCl3), δ (ppm): 199.8,
144.1, 143.7, 137.3, 134.4, 133.2, 129.3, 129.0, 128.7, 125.7,
122.4, 62.2, 41.3, 34.8, 21.7, 21.2, 21.1; HR-MS (EI-TOF) (M+)
calculated for C21H22O 290.1671, found 290.1668.
Notes and references
4-Tolyl(3-(4-tolyl)cyclopent-2-en-1-yl)methanone (4a). White
solid (23.5 mg, 85% yield); mp: 162–163 °C; 1H NMR
(400 MHz, CDCl3), δ (ppm): 7.94 (d, J = 8.4 Hz, 2H, Ar),
7.34–7.28 (m, 4H, Ar), 7.10 (d, J = 8.0 Hz, 2H, Ar), 6.12 (q, J =
2.0 Hz, 1H, CHCHvC), 4.66–4.61 (m, 1H, CHCHvC),
2.95–2.76 (m, 2H, CHCH2CH2), 2.53–2.43 (m, 4H, CHCHHCH2
and COArCH3), 2.38–2.30 (m, 4H, CHCHHCH2 and CH3); 13C
NMR (100 MHz, CDCl3), δ (ppm): 200.0, 145.0, 143.7, 137.3,
134.1, 133.1, 129.3, 129.0, 128.7, 125.8, 122.9, 54.4, 33.1, 26.4,
21.7, 21.2; HR-MS (EI-TOF) (M+) calculated for C20H20O
276.1514, found 276.1514.
1 For
reviews
on
Rauhut–Currier
reactions,
see:
(a) C. E. Aroyan, A. Dermenci and S. J. Miller, Tetrahedron,
2009, 65, 4069–4084; (b) J. L. Methot and W. R. Roush, Adv.
Synth. Catal., 2004, 346, 1035–1050; (c) K. C. Bharadwaj,
RSC Adv., 2015, 5, 75923–75946.
2 P. Xie and Y. Huang, Eur. J. Org. Chem., 2013, 6213–6226.
3 (a) C. Hu, Z. Geng, J. Ma, Y. Huang and R. Chen, Chem. –
Asian J., 2012, 7, 2032–2035; (b) R. Zhou, J. Wang, J. Tian
and Z. He, Org. Biomol. Chem., 2012, 10, 773–781; (c) C. Hu,
Q. Zhang and Y. Huang, Chem. – Asian J., 2013, 8, 1981–
1984; (d) M. Couturier, F. Ménard, J. A. Ragan, M. Riou,
E. Dauphin, B. M. Andresen, A. Ghosh, K. Dupont-Gaudet
and M. Girardin, Org. Lett., 2004, 6, 1857–1860.
4 (a) W. Yao, Y. Wu, G. Wang, Y. Zhang and C. Ma, Angew.
Chem., Int. Ed., 2009, 48, 9713–9716; (b) P. Xie, Y. Huang
and R. Chen, Org. Biomol. Chem., 2011, 9, 6707–6714.
5 L. Cai, B. Zhang, G. Wu, H. Song and Z. He, Chem.
Commun., 2011, 47, 1045–1047.
(4-Chlorophenyl)(3-(4-chlorophenyl)cyclopent-2-en-1-yl)-
methanone (4d). Yellow solid (22.2 mg, 70% yield); mp:
1
97–98 °C; H NMR (400 MHz, CDCl3), δ (ppm): 7.97 (d, J = 8.4
Hz, 2H, Ar), 7.47 (d, J = 8.8 Hz, 2H, Ar), 7.36 (d, J = 8.0 Hz, 2H,
Ar), 7.27 (d, J = 8.4 Hz, 2H, Ar), 6.13 (q, J = 2.0 Hz, 1H,
CHCHvC), 4.63–4.59 (m, 1H, CHCHvC), 2.92–2.77 (m, 2H,
CHCH2CH2), 2.51–2.33 (m, 2H, CHCH2CH2); 13C NMR
(100 MHz, CDCl3), δ (ppm): 198.9, 144.5, 139.6, 134.8, 134.1,
133.4, 130.0, 129.1, 128.5, 127.2, 123.9, 54.4, 33.0, 26.5; HR-MS
(EI-TOF) (M+) calculated for C18H14Cl2O 316.0422, found
316.0423.
6 J. Ma, P. Xie, C. Hu, Y. Huang and R. Chen, Chem. – Eur. J.,
2011, 17, 7418–7422.
7 N. T. McDougal and S. E. Schaus, Angew. Chem., Int. Ed.,
2006, 45, 3117–3119.
Naphthalen-2-yl(3-(naphthalen-2-yl)cyclopent-2-en-1-yl)-
methanone (4f). White solid (31.0 mg, 89% yield); mp:
152–153 °C; H NMR (400 MHz, CDCl3), δ (ppm): 8.60 (s, 1H,
Ar), 8.12 (dd, J = 8.6, 1.8 Hz, 1H, Ar), 8.01 (d, J = 8.0 Hz, 1H,
Ar), 7.95–7.89 (m, 2H, Ar), 7.82–7.73 (m, 4H, Ar), 7.67–7.56 (m,
3H, Ar), 7.47–7.41 (m, 2H, Ar), 6.39 (q, J = 2.0 Hz, 1H,
8 Y.-Q. Li, H.-J. Wang and Z.-Z. Huang, J. Org. Chem., 2016,
81, 4429–4433.
9 (a) T. Hudlicky and J. D. Price, Chem. Rev., 1989, 89, 1467–
1486; (b) R. C. Hartley and S. T. Caldwell, J. Chem. Soc.,
Perkin Trans. 1, 2000, 477–501; (c) B. Heasley, Eur. J. Org.
Chem., 2009, 1477–1489.
1
CHCHvC), 4.92–4.87 (m, 1H, CHCHvC), 3.13–2.96 (m, 2H, 10 CCDC 2022239† contains the supplementary crystallo-
CHCH2CH2), 2.66–2.44 (m, 2H, CHCH2CH2); 13C NMR
graphic data for 3da.
This journal is © The Royal Society of Chemistry 2021
Org. Biomol. Chem., 2021, 19, 2487–2491 | 2491