Photoredox catalysed allylic trifluoromethylation via ring opening of vinyl cyclopropanes using Langlois reagent

Article abstract of DOI:10.1016/j.tet.2019.130641

Trifluoromethylation of vinylcyclopropanes (VCPs) has been developed under mild reaction conditions to synthesize allylic trifluoromethylated derivatives with high yield and E/Z selectivity using visible light photo-redox catalysis and Langlois reagent (CF₃SO₂Na) as a trifluoromethylation source. Further, we demonstrate a gram scale synthesis procedure for a trifluoromethylation of vinylcyclopropane.

Full text of DOI:10.1016/j.tet.2019.130641

Tetrahedron xxx (xxxx) xxx
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Photoredox catalysed allylic trifluoromethylation via ring opening of
vinyl cyclopropanes using Langlois reagent
Palasetty Chandu, Krishna Gopal Ghosh, Debabrata Das, Devarajulu Sureshkumar*
Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, West Bengal, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Trifluoromethylation of vinylcyclopropanes (VCPs) has been developed under mild reaction conditions to
synthesize allylic trifluoromethylated derivatives with high yield and E/Z selectivity using visible light
photo-redox catalysis and Langlois reagent (CF3SO2Na) as a trifluoromethylation source. Further, we
demonstrate a gram scale synthesis procedure for a trifluoromethylation of vinylcyclopropane.
© 2019 Elsevier Ltd. All rights reserved.
Received 28 August 2019
Received in revised form
23 September 2019
Accepted 24 September 2019
Available online xxx
Keywords:
Allylic trifluoromethylation
Photoredox catalysis
Vinylcyclopropanes (VCP)
Langlois reagent
1. Introduction
Replacing a methyl with trifluoromethyl group in a drug changes
many properties like metabolic reliability, electrostatic attractions
Vinylcyclopropanes (VCPs) are one of the most important syn-
thons in organic synthesis because they are used as a versatile
starting material to synthesize many complex building blocks in
natural products, agrochemicals, and pharmaceutical drugs [1].
VCP, with electron withdrawing groups can act as 1,3-dipoles for
cyclo-addition reactions in the presence of transition metals [2].
Transition metal catalysed incorporation of new and different
functional groups into donor-acceptor cyclopropanes via ring
opening strategy has been well studied in various organic trans-
formations [3]. Similarly electrophilic ring opening of VCPs offers
various functional motifs that can be further transformed into
useful molecular scaffolds of interest [4a]. There are several liter-
ature reports on radical mediated functionalization of VCPs [4b-c].
These strategies have some drawbacks such as a) use of metals like
selenium [5], (TMS)3Si-H [6] or Sn-H [7] as common radical initi-
ators with equivalent amount of various external oxidants b) dif-
ficulty in controlling radical reactivity causing hindrances to
formation of desired product and c) challenges in controlling
selectivity. We are interested in visible light mediated radical tri-
fluoromethylation of VCPs because of high electro-negativity of
fluorine that can alter the physical properties of a compound [8].
towards targets, lipophilicity, bio-availability, and increased sta-
bility against oxidative metabolism of the drug [8,9]. Thus, tri-
fluoromethyl group has gained a tremendous importance in the
field of pharmaceutical and agrochemical synthesis [10].
Past decade has been experienced a “Renaissance in Radical
Trifluoromethylation” as evident from various reports [11]. How-
ever, most of the reported work has been in a limited area of either
aromatic rings, heterocycles (Csp2_CF3) or Csp_CF3 [12], very few
reports are available on direct Csp3_CF3 and allylic tri-
fluoromethylation [13]. Particularly for allylic trifluoromethylation,
challenges associated with control of regio- and stereo selectivity
has been major reasons for slow progress in this area [14a]. Allylic
trifluoromethyl compounds are potential building blocks for the
synthesis of the trifluoromethylating drugs [14b]. There are few
reports for the allylic trifluoromethylation of alkenes using elec-
trophilic trifluoromethylating reagents Togni [15] and Umemoto
[15] (Scheme 1a). Feng Liu's group reported dihydronaphthalene
derivatives by activated vinylcyclopropanes using Togni reagent
[16a]. Extensive literature survey suggests that all previously re-
ported protocol suffers from huge drawbacks such as expensive
electrophilic CF3 reagents, lower yields and selectivity, which ulti-
mately prevents their use in practical applications [15,16a].
Recently our group reported trifluoromethylation of vinyl-
cyclopropanes using pyrylium salts as a photocatalyst [16b]. Here,
we report visible light photoredox method of catalytic
* Corresponding author.
E-mail address: suresh@iiserkol.ac.in (D. Sureshkumar).
https://doi.org/10.1016/j.tet.2019.130641
0040-4020/© 2019 Elsevier Ltd. All rights reserved.
Please cite this article as: P. Chandu et al., Photoredox catalysed allylic trifluoromethylation via ring opening of vinyl cyclopropanes using
Langlois reagent, Tetrahedron, https://doi.org/10.1016/j.tet.2019.130641

2
P. Chandu et al. / Tetrahedron xxx (xxxx) xxx
Scheme 1. a) Previous Work on Allylic Trifluoromethylation. b) Recent Reports on Trifluoromethylation of Vinylcyclopropanes.
trifluoromethylation for the synthesis of allylic trifluoromethylated
products via radical mediated ring opening of VCPs using cheap CF3
reagent (Langlois' reagent) and Ir-photocatalyst with good yields
and high E/Z selectivity.
different photocatalysts. The following photocatalysts (Ru(b-
py)3Cl2$6H2O {E1/2 ¼ [*RuII/RuI] ¼ þ0.77 V vs SCE in MeCN} [19],
Ir(ppy)2(dtbbpy)PF6
(dtbbpy ¼ 4,40-Di-tert-butyl-2,20-dipyridyl)
{E1/2 ¼ [*IrIII/IrII] ¼ þ0.66 V vs SCE in MeCN} [20] and fac-Ir(ppy)3
red
(ppy ¼ 2-phenylpyridine) {E [*IrIII/IrII] ¼ þ0.31 V vs SCE in MeCN}
1/2
[21] are totally ineffective for this reaction as all three have excited
state potential much lower than þ1.05 V of Langlois reagent's
oxidation potential [18].
2. Result and discussion
Recent studies on trifluoromethylation by photo-redox catalysis
showed that the excited state of photocatalyst (PC*) can generate
Ir[dF(CF3)ppy]2(dtbbpy)PF6 Ir1 (dF(CF3)ppy ¼ 3,5-difluoro-2-[5-
red
(trifluoromethyl)-2-pyridinyl]phenyl){E [*IrIII/IrII] ¼ þ1.21 V and
1/2
Er1e/2d[IrIII/IrII] ¼ ꢁ1.37 V vs SCE in MeCN} [22] is very effective
because of its compatible range of redox potential. In the case of
excited state reductive quenching cycle, it has higher potential than
the þ1.05 V, thus it is expected that catalyst Ir1 would oxidise the
trifluoromethanesulfinate anion to form CF3 radical. Although,
CF3 radical from CF3SO2Na (Langlois reagent) [17a-d]. The reagent
oxi
has a very high oxidation potential {CF3SO2Na/CFꢀ3, E ¼ þ1.05 V vs
1/2
SCE} making it difficult to generate CF3 radical by oxidation [18].
Only a photo-catalyst with excited state oxidation potential higher
than þ1.05 V can generate CF3 radical [18]. We hypothesized that
such a photo-catalyst could generate CF3 radical that could be
incorporated into the double bond via ring opening of VCP. To
assess our hypothesis, we have chosen 1a as model substrate and
investigated reported conditions of trifluoromethylation [17e and
f], but found them ineffective (entry 1 and 2). Then, we optimized
different photocatalysts as depicted in Table 1. We found that using
2 mol% Ru(bpz)3(PF6)2 (bpz ¼ 2,20-Bipyrazine) as photoredox cata-
lyst with VCP 1a and CF3SO2Na in MeOH under the irradiation of
blue LEDs in inert conditions, the trifluoromethylated product 2a
could be obtained in 21% yield (Entry 4). In case of [Ir
{dFCF3ppy}2(dtbbpy)]PF6 photocatalyst, yield improved to 73%
(entry 6). Interestingly, screening of Acridinium photocatalyst could
only produce 42% yield (entry 5). There was no reaction in case of
[Ir(ppy)2(dtbbpy)]PF6 and fac-Ir(ppy)3 photocatalysts (entry 7 and
8). Further solvent optimization study (entry 9e13) revealed DME
to be the most effective solvent for this reaction that could enhance
the yield up to 82%. As the yield was moderate, there was an ab-
solute need for a proton source for smooth completion of the re-
action. For this, we optimized different proton sources and found
out that 20 equiv. of H2O could increase the yield up to 94% (entry
14). The reaction did not proceed in the absence of irradiation or
photoredox catalyst (entry 17 and 18). We could rationalize the
outcome of the optimization results with the oxidation potential of
red
red
Acridinium catalyst {E ¼ [*Acr/Acrꢁ] ¼ þ2.06 V and E ¼ [Acr/
1/2
1/2
Acre] ¼ ꢁ0.57 V} [23] could easily generate CF3 radical from tri-
fluoromethanesulfinate anion (as from its excited state oxidation
potential), it gave poor results probably because of its lower
reduction potential than Ir1 catalyst and also catalyst decomposes
under reaction condition.
With these optimized conditions (Table 1, entry 12), next, we
established substrate scope and limitations of our established
protocol as shown in Table 2. The optimized trifluoromethylation
conditions proved to be successful on a wide range of VCPs. The
reaction is highly chemoselective and many synthetically impor-
tant functional groups including ester, cyano, sulfonate, keto are
well tolerated in this reaction condition. Many VCPs with branched
substitutes and halogens like chloro are also compatible with this
reaction condition (Table 2). Cyano, sulfonate, keto are well toler-
ated in this reaction condition. Many VCPs with branched sub-
stitutes and halogens like chloro are also compatible with this
reaction condition (Table 2). The substrates 1a-1d bearing di car-
boxy ester groups as a EWG have furnished good yields (79%e94%)
and high Z/E ratio up to 1:27. Different substituted di-sulfonyl
group's 2e-2h showed high yields and moderate selectivity. VCP
containing di-cyano and di-keto functionality 2o, 2k also gave
Please cite this article as: P. Chandu et al., Photoredox catalysed allylic trifluoromethylation via ring opening of vinyl cyclopropanes using
Langlois reagent, Tetrahedron, https://doi.org/10.1016/j.tet.2019.130641

P. Chandu et al. / Tetrahedron xxx (xxxx) xxx
3
Table 1
Optimization of Allyl Trifluoromethylation.a
entry
photocatalyst
solvent
additive
yield % (Z/E)f
1b
2c
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17d
18e
2 mol % Ru(Phen)3Cl2
2 mol % Ru(bpy)3Cl2$6H2O
2 mol % Ru(bpy)3Cl2$6H2O
2 mol % Ru(bpz)3(PF6)2
CH3CN
CH3CN
MeOH
MeOH
MeOH
MeOH
MeOH
MeOH
CH3CN
DME
Toluene
DCM
DMF
DME
DME
K2HPO4
e
13 (1:7)
6 (1:9)
NR
21 (1:11)
42 (1:13)
73 (1:15)
NR
e
e
5 mol % Mes.Acr.ClO4
e
2 mol % Ir[(dFCF3ppy)2(dtbbpy)]PF6
2 mol % [Ir(ppy)2(dtbbpy)]PF6
2 mol % fac-Ir(ppy)3
e
e
e
NR
2 mol % Ir[(dFCF3ppy)2(dtbbpy)]PF6
2 mol % Ir[(dFCF3ppy)2(dtbbpy)]PF6
2 mol % Ir[(dFCF3ppy)2(dtbbpy)]PF6
2 mol % Ir[(dFCF3ppy)2(dtbbpy)]PF6
2 mol % Ir[(dFCF3ppy)2(dtbbpy)]PF6
2 mol % Ir[(dFCF3ppy)2(dtbbpy)]PF6
2 mol % Ir[(dFCF3ppy)2(dtbbpy)]PF6
2 mol % Ir[(dFCF3ppy)2(dtbbpy)]PF6
e
e
15 (1:6)
15 (1:6)
28 (1: 13)
15 (1:9)
46 (1:12)
94 (1:17)
76 (1:18)
80 (1:17)
NR
e
e
e
e
20 equiv. H2O
20 equiv. MeOH
20 equiv. AcOH
20 equiv. H2O
20 equiv. H2O
DME
DME
DME
2 mol % Ir[(dFCF3ppy)2(dtbbpy)]PF6
trace
a
All reaction performed in 0.15 mmol scale, 3 equiv. CF3SO2Na, 2 mol % photocatalyst, 3 mL solvent, irradiated with 27 W Blue LED under Ar atm.
b
c
d
e
f
CF3SO2Cl as a CF3 source.
Pyridine N-oxide and TFAA as a CF3 source.
No photocatalyst.
No light.
Yield based on 19F NMR using PhCF3 as an internal standard and in parenthesis Z/E ratio based on 19F NMR.
excellent yields. VCPs having a combination of two different sub-
reduction of 3ꢂ radical 5 by IrII(3) {Er1e/2d ¼ [IrIII/II] ¼ ꢁ1.37 V vs SCE}22
to give stable carbanion 6 and reform the photo catalyst 1. Further,
stituent's (2i, 2j, 2l, 2m, and 2n) gave good yields with good regio
selectivity. Trifluoromethylation of spiro-VCP's offered interesting
allylic trifluoromethylated products 2p and 2r in good yield and
regio selectivity. Further, we prepared few carbo-cyclic vinyl cy-
clopropanes as they are very important parent skeleton in many
natural products [24]. The reaction with these substrates proceeded
smoothly to form the 4-(trifluoromethyl) cyclo-2-ene derivatives
(2r, 2s, 2t) with good yield and high cis-selectivity. Finally, to
expand the scope of this methodology, we tried unactivated
vinylcyclopropanes. These are more challenging than the activated
cyclopropanes due to lower reactivity. For this, we reduced 1c to
corresponding alcohol and protected it with different groups under
optimized reactions conditions. Interestingly, this reaction led to
formation of linear allylic trifluoromethylated products 2u-2x.
Finally, scalability is the one main drawback for the photo catalytic
reactions. To demonstrate the scalability of this protocol with Ir1
photocatalyst and starting materials, we performed a gram-scale
reaction (Scheme 2) of 1e with CF3SO2Na to get the product 2e in
84% yield.
protonation of
fluoromethylated product 2a.
6
will give long alkyl chain allylic tri-
In conclusion, we have developed an efficient photoredox cat-
alysed method for the synthesis of allylic trifluoromethylated
product via ring opening of vinyl cyclopropanes (VCPs) using a
cheap Langlois reagent and Ir photocatalyst that is scalable to
higher amounts. This protocol offers wide scope for further func-
tionalization as the final product consist of active methylene group
that could act as Michael donor. We believe the scalability, cost
efficiency and broad functionalization scope of this process would
be useful to diverse research community and practical applications.
2.1. Typical experimental procedure for gram scale synthesis
To an oven dried 100 mL round bottom flask,1.04 g of compound
1e (3 mmol, 1 equiv.), 1.40 g of CF3SO2Na (9 mmol, 3 equiv.) and
67.3 mg Ir-catalyst (Ir1) (0.06 mmol, 2 mol%) was added with stir-
ring. This was degassed by alternate vacuum evacuation and Argon
backfilling process for 5 times. The reaction was sealed and 1.08 mL
of deionised H2O, 60 mL of DME solvent were added and irradiated
with blue LEDs until no 1e was observed (6 h). After complete
conversion, the reaction was quenched and crude product was
subjected to silica column chromatographic separation to obtain
the final compound 2e (84%).
To gain insight into the reaction mechanism, we performed
control experiment with radical scavenger TEMPO 3a. In the pres-
ence of TEMPO (3 equiv.), formation of TEMPO-CF3 adduct 3b was
found in 19F NMR (376 MHz, CDCl3)
clearly indicated radical pathway is the underlying mechanism. The
proposed mechanism for photoredox cycle is shown in Scheme 3.
d
ꢁ55.86 ppm (s, 3F). This
Interaction of Ir[dF(CF3)ppy]2(dtbbpy)PF6 (Ir1) with visible light
oxi
generates the strong oxidant IrIII1* {E ¼ [*IrIII/II] ¼ þ1.21 V vs SCE
1/2
3. Experimental section
in MeCN} [22] in excited-state. This can readily oxidise the Langlois
oxi
reagent 2 {CF3SO2Na/CFꢀ3, E ¼ þ1.05 V vs SCE} [18] to generate the
1/2
3.1. General information
CF3 radical. Incorporation of CF3 into the terminal alkene of the VCP
would generate intermediate 4 by ring opening and form a more
stable 3ꢂ radical 5. Finally, the catalytic cycle could be completed by
Commercial reagents and solvents were purified prior to use
following the guidelines of L.L Chai and Armarego [25]. All NMR
Please cite this article as: P. Chandu et al., Photoredox catalysed allylic trifluoromethylation via ring opening of vinyl cyclopropanes using
Langlois reagent, Tetrahedron, https://doi.org/10.1016/j.tet.2019.130641

4
P. Chandu et al. / Tetrahedron xxx (xxxx) xxx
Table 2
Substrate scope for trifluoromethylation of VCP Derivativesa.
aAll reactions performed in 0.15 mmol substrate, 3 equiv. CF3SO2Na, 2 mol % photocatalyst, 20 equiv. H2O, irradiated under blue LEDs for 6 h in Ar atm. and isolated
yields.breaction performed in 0.3 mmol scale, c5 equiv. CF3SO2Na, d18 h and in parenthesis Z/E ratio based on 19F NMR.
Scheme 2. Gram Scale Synthesis of Compound 2e.
spectra were recorded on 400 MHz Jeol spectrometers. 1H, 13C and
19F NMR spectral data are reported as chemical shifts (
) in parts per
million (ppm) relative to the solvent residual peak using the Jeol
internal referencing procedure (edlock). Chemical shifts ( ) are
quoted in parts per million (ppm) and coupling constants (J) are
measured in hertz (Hz). The following abbreviations are used to
describe multiplicities s ¼ singlet, d ¼ doublet, t ¼ triplet,
q ¼ quartet, pent ¼ pentet, br ¼ broad, m ¼ multiplet, dd ¼ doublet
of doublet. High resolution mass spectra (HRMS, m/z) were recor-
ded on a Bruker MicroTOF. IR spectra were recorded on Perkin
Elmer Frontier FT-IR spectrometer. All reactions for tri-
fluoromethylation of Vinylcyclopropanes were conducted in dried
d
d
Please cite this article as: P. Chandu et al., Photoredox catalysed allylic trifluoromethylation via ring opening of vinyl cyclopropanes using
Langlois reagent, Tetrahedron, https://doi.org/10.1016/j.tet.2019.130641

P. Chandu et al. / Tetrahedron xxx (xxxx) xxx
5
Scheme 3. Proposed Mechanism for Trifluoromethylation of Vinylcyclopropanes.
glassware with magnetic stirring under an inert atmosphere, unless
otherwise noted. Thin Layer Chromatography (TLC) was performed
using Silica gel 60 F254 and visualized under ultraviolet light. Flash
column chromatography was performed over Merck Silica gel
(13 mg, 0.03 mmol) and freshly cracked cyclopentadiene (2.8 mL,
32.5 mmol). Dimethyl 2-diazomalonate (0.86 mL, 6.5 mmol) was
added neat over 10 h by means of a gas-tight syringe (using syringe
pump) at room temperature. The solution was run through a
pipette plug of silica and eluted with hexane. The collected organic
layer was concentrated and purified by medium pressure liquid
chromatography using 5% EtOAc and hexane as eluent to obtain the
compound 1r in 61% yield (779 mg) as colorless oil. 1H NMR
(230e400 mm). IrCl3$xH2O was purchased from Souvenier chem-
icals, CF3SO2Na purchased from TCI chemical. All metal catalysts
were either prepared by reported literature procedure or pur-
chased from the Sigma-Aldrich and used without further purifica-
tion. Unless otherwise specified, other reagents were obtained from
commercial suppliers Alfa Aesar, and Spectrochem. In a general
(400 MHz, CDCl3):
1H), 3.68 (s, 3H), 3.60 (s, 3H), 2.82e2.59 (m, 3H), 2.40 (t, J ¼ 6.1 Hz,
d
5.76 (dd, J ¼ 3.8, 1.2 Hz, 1H), 5.58 (d, J ¼ 5.3 Hz,
experiment,
a
9 ꢃ 3 W blue LEDS were connected in series
1H).13C NMR (101 MHz, CDCl3):
52.2, 39.3, 38.6, 34.3, 31.6.
d 170.3, 166.5, 132.1, 129.4, 52.6,
connection and used as a visible light source with a cooling fan.
3.2. Synthesis of vinylcyclopropanes
3.3.2. Dimethyl-bicyclo[4.1.0]hept-2-ene-7,7-dicarboxylate (1s)
[16] In an oven-dried 10 mL sealed tube equipped with a mag-
netic stir bar under Argon, was added Rh2(OAc)4 (13 mg,
0.03 mmol). Dimethyl 2-diazomalonate (0.86 mL, 6.5 mmol) and
excess of cyclohexadiene (5e10 eq.) were added. The reaction
mixture was heated to 120 ꢂC for 1 h, until no dimethyl 2-
diazomalonate remained. Reaction mixture was concentrated and
purified by silica column using 5% EtOAc and hexane. The com-
pound 1s was isolated as gummy solid in 93% yield (1.3 g) which
Vinylcyclopropanes (1a-1e, 1k) were prepared according to re-
ported literature procedure [26] and other vinylcyclopropanes (1f-
1j, 1l-1q) were synthesized following same protocol. The corre-
sponding active methylene compound (2 mmol, 1 equiv.) and 1,4-
dibromobut-2-ene (1 equiv.) were added to a round bottom flask
with a stir bar under nitrogen atmosphere. To this, THF (0.2 M) and
Cesium carbonate (2.5 equiv.) were added. After fitting the
condenser, reaction mixture was stirred for overnight at 60 ꢂC. After
cooling to room temperature, the reaction mixture was filtered over
Celite and washed with diethyl ether. The organic phase was
washed with saturated aqueous NaHCO3, followed by water and
brine. After filtration over Na2SO4, the solvent was removed under
reduced pressure. The crude product was purified by silica gel
column chromatography using hexane and ethyl acetate as the
eluent. Corresponding vinylcyclopropanes were obtained as solid/
liquid with good yields.
became solid at 20 ꢂC; 1H NMR (400 MHz, CDCl3):
d 5.92e5.76 (m,
1H), 5.72e5.57 (m, 1H), 3.72 (s, 3H), 3.71 (s, 3H), 2.17e1.56 (m, 6H).
13C NMR (101 MHz, CDCl3):
40.7, 26.6, 24.4, 20.4, 15.9.
d 170.0, 167.6, 127.8, 121.7, 52.6, 52.4,
3.3.3. Dimethyl-bicyclo[6.1.0]non-2-ene-9,9-dicarboxylate (1t)
[16] In an oven-dried 10 mL Sealed tube equipped with a mag-
netic stir bar under Argon, was added Rh2(OAc)4 (13 mg,
0.03 mmol). Dimethyl 2-diazomalonate (0.86 mL, 6.5 mmol) was
added followed by excess of cyclooctadiene (2e5 equiv.). Reaction
mixture was heated to 120 ꢂC for 1 h, until no dimethyl 2-
diazomalonate remains. Reaction mixture was concentrated and
purified by silica column using 5% EtOAc and hexane. The com-
pound 1t was isolated as colorless oily liquid in 68% yield (1.05 g).
3.3. Synthesis of the carbocyclic vinylcyclopropanes
3.3.1. Dimethyl-bicyclo[3.1.0]hex-2-ene-6,6-dicarboxylate (1r)
[16] In an oven-dried 50 mL Schlenk tube equipped with a
magnetic stir bar and cooled under Argon, was added Rh2(OAc)4
1H NMR (400 MHz, CDCl3):
d
5.77 (tdd, J ¼ 7.2, 4.4, 2.4 Hz, 1H), 5.54
Please cite this article as: P. Chandu et al., Photoredox catalysed allylic trifluoromethylation via ring opening of vinyl cyclopropanes using
Langlois reagent, Tetrahedron, https://doi.org/10.1016/j.tet.2019.130641

6
P. Chandu et al. / Tetrahedron xxx (xxxx) xxx
(d, J ¼ 11.3 Hz, 1H), 3.72 (s, 3H), 3.71 (s, 3H), 2.45e2.31 (m, 2H),
2.07e1.68 (m, 6H), 1.51e1.36 (m, 1H), 1.11 (ddd, J ¼ 15.2, 12.5, 3.1 Hz,
in 89% yield (410 mg). 1H NMR (400 MHz, CDCl3):
d 5.67e5.54 (m,
1H), 5.14 (d, J ¼ 16.8 Hz, 1H), 5.04 (dd, J ¼ 9.2, 8.1 Hz,1H), 4.20 (d, J ¼
12 Hz,1H), 4.11 (d, J ¼ 11.5 Hz,1H), 3.91 (dd, J ¼ 11.7, 7.3 Hz, 2H), 1.65
(dd, J ¼ 14.3, 7.5 Hz, 1H),1.25 (s, 9H), 1.20 (s, 9H), 1.01e0.93 (m, 1H),
1H). 13C NMR (101 MHz, CDCl3):
d 171.1, 167.0, 136.2, 120.5, 52.6,
52.0, 36.0, 32.8, 30.1, 29.6, 29.5, 24.7, 23.9.
0.77 (t, J ¼ 5.7 Hz, 1H). 13C NMR (101 MHz, CDCl3):
d 178.4, 174.0,
3.4. Synthesis of the unactivated vinylcyclopropanes
135.1, 116.5, 67.5, 64.1, 40.2, 38.9, 38.8, 27.1, 26.5, 25.8, 25.1, 15.6. IR
data (KBr, in cmꢁ1): 1813, 1729, 1483, 1403, 1281, 1141, 1001, 604.
HRMS (ESI-TOF) m/z: [M þ H]þ calcd for C17H29O4 297.2060; Found:
297.2059.
3.4.1. (2-Vinylcyclopropane-1,1-diyl)dimethanol (S1)
[16] A solution of diester 1c (14 mmol) in THF (50 mL) was
cooled to 0 ꢂC and LiAlH4 (4 equiv.) was added in several portions.
After heating for 2 h at 60 ꢂC, the mixture was cooled to room
temperature, 2 mL H2O followed by 1 M solution of Rochelle's salt
(10 mL) were cautiously added and the layers separated out. The
solid residue was filtered and the filtrate was concentrated, then
extract with 3 ꢃ 50 mL DCM. The combined organic layers were
dried over Na2SO4. After evaporation of solvent, di-alcohol S1
appeared as colorless liquid, which was used further without pu-
3.4.4. (2-Vinylcyclopropane-1,1-diyl)bis(methylene)dibenzoate
(1w)
[16] A solution of 200 mg (1.6 mmol) of (2-vinylcyclopropane-
1,1-diyl)dimethanol S1 in 5 mL of pyridine stirred at 0 ꢂC under dry
conditions was treated with 15.2 mL (680 mg, 4.8 mmol) of benzoyl
chloride (added dropwise over 15 min). The reaction mixture was
stirred at room temperature for 2 h, then treated with 2 mL of H2O,
and stirred overnight. The mixture was concentrated under
reduced pressure. The residual oil was dissolved in 50 mL of EtOAc
and washed successively with sat. CuSO4 solution and bicarbonate.
The organic phase was dried (MgSO4), filtered, concentrated and
purified by column chromatography using 5e10% EtOAc and hex-
ane to obtain compound 1w as colorless oil in 77% yield (410 mg);
rification (1.7 g, crude yield 95%); 1H NMR (400 MHz, CDCl3)
d 5.67
(ddd, J ¼ 17.02, 10.14, 8.09 Hz, 1H), 5.15 (dd, J ¼ 17.02, 0.85 Hz, 1H),
5.04 (dd, J ¼ 10.14, 0.85 Hz, 1H), 3.83 (dd, J ¼ 11.71, 6.52 Hz, 1H),
3.63e3.57 (m, 3H), 3.30 (br s, 2H), 1.63e1.51 (m, 1H), 0.83 (dd, J
8.09, 5.43 Hz, 1H), 0.65 (t, J 5.43 Hz,1H). 13C NMR (101 MHz, CDCl3):
d
136.2, 115.9, 69.1, 64.4, 30.5, 25.2, 15.5.
1H NMR (400 MHz, CDCl3):
d
8.03 (dd, J ¼ 7.0, 1.4 Hz, 4H), 7.55 (dd,
3.4.2. 4,4'-(Vinylcyclopropane1,1diyl)bis(methylene)bis(oxy))
bis(methylene)bis((trifluoro-methyl)benzene) (1u)
J ¼ 14.8, 7.2 Hz, 2H), 7.40 (t, J ¼ 7.7 Hz, 4H), 5.83e5.68 (m, 1H), 5.24
(d, J ¼ 16.9 Hz, 1H), 5.12 (d, J ¼ 10.4 Hz, 1H), 4.64 (d, J ¼ 12.0 Hz, 1H),
4.36 (dt, J ¼ 17.5, 11.8 Hz, 3H), 1.87 (dd, J ¼ 14.5, 7.5 Hz, 1H), 1.16 (dd,
J ¼ 8.4, 5.5 Hz, 1H), 0.97 (t, J ¼ 5.8 Hz, 1H). 13C NMR (101 MHz,
16[16] A 25 mL two neck round bottom flask was dried using hot
air gun under Argon atmosphere. To this, added 3 equivalents of
NaH (55% washed with pentane) and Argon backfilled for 3 times.
Reaction mixture was cooled to 0 ꢂC then 200 mg (1.56 mmol) of (2-
vinylcyclopropane-1,1-diyl)dimethanol S1 in DMF (5 mL) was
added slowly and, stirred for 15 min. Then 1-(bromomethyl)-4-
(trifluoromethyl)benzene 1.1 g (4.5 mmol) in DMF was added drop
wise over 15 min. The mixture was stirred at room temperature
overnight. Reaction was quenched by adding water, then extracted
with 2 ꢃ 10 mL ethyl acetate. The organic layer was washed with
H2O (4 ꢃ 10 mL) and brine respectively. Combined organic layers
were dried over Na2SO4, evaporated and purified by column chro-
matography using 5% EtOAc and hexane as eluent to obtain product
CDCl3):
d 166.5, 134.9, 133.0, 132.9, 130.1, 130.0, 129.6, 128.3, 128.3,
116.9, 69.1, 65.3, 25.8, 25.7, 15.9.
3.4.5. (2-Vinylcyclopropane-1,1-diyl)bis(methylene)diacetate (1x)
[16] A 25 mL of two neck round bottom flask was dried by heat
gun under nitrogen atmosphere. After nitrogen was filled, to the
solution of (2-vinylcyclopropane-1,1-diyl)dimethanol S1 (150 mg,
1.2 mmol) in pyridine (0.6 mL), added anhydrous acetic anhydride
(1.5 mL) dropwise. The resulting mixture was stirred at room
temperature for 24 h. After cooling to 0 ꢂC, 4 mL of H2O was added
slowly. The reaction mixture was filtered and extracted with DCM
(4 ꢃ 10 mL). The combined organic layers were washed succes-
sively with sat. aq. CuSO4 (10 mL), 5% HCl (10 mL), sat. aq. NaHCO3
(10 mL), and brine (10 mL). The organic layer was dried over MgSO4
and concentrated under reduced pressure. The residue was purified
by column chromatography using 5e10% EtOAc and hexane to
obtain compound 1x in 53% yield (135 mg); 1H NMR (400 MHz,
1u in 78% yield (520 mg); 1H NMR (400 MHz, CDCl3):
d
7.57 (d, J ¼
7.9 Hz, 4H), 7.42 (d, J ¼ 7.9 Hz, 4H), 5.74e5.55 (m, 1H) 5.15 (d, J ¼
16.5 Hz, 1H), 5.05 (d, J ¼ 10.0 Hz, 1H), 4.56 (s, 2H), 4.54 (d, J ¼ 2.9 Hz,
2H), 3.68 (d, J ¼ 10.1 Hz, 1H), 3.62 (d, J ¼ 9.8 Hz, 1H), 3.42 (d, J ¼
10.1 Hz, 1H), 3.34 (d, J ¼ 9.8 Hz, 1H), 1.59 (dd, J ¼ 15.0, 8.4 Hz, 1H),
0.93 (dd, J ¼ 8.4, 5.2 Hz, 1H), 0.71 (t, J ¼ 5.2 Hz, 1H). 13C NMR
(101 MHz, CDCl3):
d
142.6, 136.1, 127.5, 127.4, 126.9 (q, 272 Hz),
CDCl3):
d
5.63 (ddd, J ¼ 10.6, 8.9, 5.7 Hz,1H), 5.15 (d, J ¼ 16.8 Hz,1H),
125.3, 125.2, 125.2, 115.7, 74.5, 72.1, 72.0, 70.1, 27.3, 25.0, 15.3. 19F
5.07 (d, J ¼ 10.6 Hz, 1H), 4.20 (d, J ¼ 12.0 Hz, 1H), 4.07 (d, J ¼ 12.0 Hz,
1H), 3.99 (d, J ¼ 12.0 Hz, 1H), 3.93 (d, J ¼ 12.0 Hz, 1H), 2.07 (s, 1H),
2.05 (s, 1H), 1.70e1.62 (m, 1H), 0.96 (dd, J ¼ 8.5, 5.5 Hz, 1H), 0.78 (t,
NMR (471 MHz, CDCl3):
d
ꢁ62.54 (s, 6F). IR data (KBr, in cmꢁ1):
1399, 1330, 1190, 1123. HRMS (ESI-TOF) m/z: [M þ H]þ calcd for
C
23H23F6O2 445.1597; Found: 445.1597.
J ¼ 5.5 Hz, 1H). 13C NMR (101 MHz, CDCl3):
d 171.1, 134.9, 116.8, 68.2,
64.2, 25.5, 25.4, 20.9, 20.8, 15.6.
3.4.3. (2-Vinylcyclopropane-1,1-diyl)bis(methylene)bis(2,2-
dimethylpropanoate) (1v)
3.4.6. General procedure for synthesis of [Ir{dF(CF3)ppy}2(dtbpy)]
PF6Complex
[16] A 25 mL of round bottom two neck flask was dried by heat
gun under Argon atm. To this added 20 mol% of DMAP and Argon
backfilled for 3 times. Then, 1.0 mL of pyridine was added and
cooled to 0 ꢂC followed by addition of 200 mg (1.56 mmol) of (2-
vinylcyclopropane-1,1-diyl)dimethanol S1 in DCM (5 mL) slowly
and stirred for 15 min. Next, tert-butyl acetyl chloride (40.7 mmol)
in DCM was added drop wise over 15 min. Reaction mixture was
stirred overnight at room temperature. Reaction mixture was
diluted with DCM, washed with CuSO4, brine solution and dried
over Na2SO4. Solvent was evaporated under reduced pressure and
purified by flash column chromatography using 5% EtOAc and
hexane as eluent. Compound 1v was obtained as a colorless liquid
[27] Heteroleptic iridium complex Ir1 was synthesized in a two-
step procedure. In the first step, chloro-bridged dimer was syn-
thesized by charging a two-necked reaction flask with magnetic
stirbar, iridium (III) chloride (1 equiv), ligand (2.26 equiv), and a 2:1
v:v mixture of 2-methoxyethanol/water. The mixture was degassed
with Ar and heated under reflux at 120 ꢂC overnight. The reaction
mixture was then cooled to room temperature and filtered. The
precipitate was washed with water, dried under vacuum and taken
to the second step without further purification. In the second step,
the chloro bridging dimer (1 equiv), bipyridyl ligand (2.2 equiv) and
ethylene glycol were placed in a two-necked flask and then flushed
Please cite this article as: P. Chandu et al., Photoredox catalysed allylic trifluoromethylation via ring opening of vinyl cyclopropanes using
Langlois reagent, Tetrahedron, https://doi.org/10.1016/j.tet.2019.130641

P. Chandu et al. / Tetrahedron xxx (xxxx) xxx
7
with Argon. The mixture was heated at 150 ꢂC for 24 h and then
cooled. The cooled reaction mixture was washed hexane and
heated to 85 ꢂC for 5 min to remove the residual hexane and
aqueous ammonium hexafluorophosphate (2 g for each 100 mg
IrCl3) was added to the reaction mixture causing the iridium-PF6
salt to precipitate, which was filtered, purified on silica column
using DCM/Hexane as eluent dried under vacuum for 6 h and the
Ir1 complex was isolated as yellow solid (74% yield).
(m, 2H), 3.33 (t, J ¼ 7.6 Hz, 1H), 2.83e2.67 (m, 2H), 2.62 (t, J ¼ 7.2 Hz,
2H), 1.23 (d, J ¼ 6.4 Hz, 12H). 13C NMR (101 MHz, CDCl3):
d 168.2,
133.6, 125.8 (q, J ¼ 276.5 Hz), 120.8 (d, J ¼ 3.4 Hz), 69.0, 51.9, 31.4,
37.2 (q, J ¼ 29.8 Hz), 21.6, 21.5. 19F NMR (376 MHz, CDCl3):
ꢁ66.49
d
(t, J ¼ 10.6 Hz). FT-IR (KBr, in cmꢁ1): 2985, 2936, 2881, 1747, 1731,
1471, 1432, 1374, 1340, 1272, 1253, 1178, 1139, 1105, 1057, 972, 911,
844, 824, 647. HRMS (ESI-TOF) m/z: [M
14H21F3O4Na 333.1284; Found: 333.1280.
þ
Na]þ calcd for
C
3.5. General procedure for the allylic trifluoromethylation of
vinylcyclopropanes
3.5.5. (E)-(6,6,6-Trifluorohex-3-ene-1,1-diyldisulfonyl)dibenzene
(2e)
White solid, (mp: 98e102 ꢂC), dr (1 : 13); (55.8 mg, yield 89%);
1H NMR (400 MHz, CDCl3):
d
7.95e7.91 (m, 4H), 7.68 (t, J ¼ 7.6 Hz,
To an oven dried borosilicate test tube equipped with a mag-
netic stir bar, was added VCP (0.15 mmol, 1 eq.), CF3SO2Na
2H), 7.55 (t, J ¼ 7.9 Hz, 4H), 5.80e5.66 (m, 1H), 5.46e5.30 (m, 1H),
4.50 (t, J ¼ 6.0 Hz,1H), 2.93 (t, J ¼ 6.3 Hz, 2H), 2.77e2.65 (m, 2H). 13
C
(0.45 mmol,
3
eq.) and 2 mol% photocatalyst [Ir{dF(CF3)
ppy}2(dtbpy)]PF6 (3.4 mg, 0.02 equiv.). The reaction tube was vac-
uumed and backfilled with Argon (3 times) and sealed with a
septum. To this, 3 mL of DCE was added using a syringe, and the
reaction tube placed ~5 cm distance from the light setup. After 6 h,
10 mL of water was added and extracted with DCM (3 ꢃ 20 mL). The
combined organic layer was dried over Na2SO4 and solvent was
removed under reduced pressure. The crude product was then
purified by flash column chromatography on silica gel mesh
230e400 using hexane and EtOAc as eluent to give the tri-
fluoromethylated product.
NMR (101 MHz, CDCl3):
d 137.6, 134.7, 131.4, 129.5, 129.4, 129.2,
129.1, 125.5 (q, J ¼ 276.8 Hz), 122.4 (d, J ¼ 3.2 Hz), 83.0, 36.9 (q, J ¼
29.9 Hz), 28.6. 19F NMR (376 MHz, CDCl3):
d
ꢁ66.04 (t, J ¼ 10.7 Hz).
FT-IR (KBr, in cmꢁ1): 3171, 2935, 2853, 1816, 1585, 1480, 1379, 1328,
1311, 1293, 1270, 1254, 1203, 1112, 1081, 997, 970, 940, 895, 841, 740,
688, 646. HRMS (ESI-TOF) m/z: [M þ H]þ calcd for C18H18F3O4S2
419.0593; Found: 419.0590.
3.5.6. (E)-4,4'-(6,6,6-Trifluorohex-3-ene-1,1-diyldisulfonyl)
bis(chlorobenzene) (2f)
White solid, (mp: 90e92 ꢂC), dr (1 : 12); (59.7 mg; yield 82%); 1H
3.5.1. (E)-Di-tert-butyl-2-(5,5,5-trifluoropent-2-en-1-yl)malonate
(2a)
NMR (400 MHz, CDCl3):
d
7.89 (d, J ¼ 8.7 Hz, 4H), 7.56 (d, J ¼ 8.5 Hz,
4H), 5.83e5.71 (m, 1H), 5.51e5.35 (m, 1H), 4.45 (t, J ¼ 6.1 Hz, 1H),
Colorless oil, dr (1 : 17); (47.6 mg, yield 94%); 1H NMR (400 MHz,
2.91 (t, J ¼ 6.5 Hz, 2H), 2.84e2.68 (m, 2H). 13C NMR (101 MHz,
CDCl3):
d
5.75e5.58 (m, 1H), 5.55e5.39 (m, 1H), 3.19 (t, J ¼ 7.6 Hz,
CDCl3):
d
141.9, 135.8, 131.1, 131.1, 129.6, 129.5, 125.5 (q, J ¼
1H), 2.81e2.67 (m, 2H), 2.54 (t, J ¼ 7.2 Hz, 2H),1.43 (s,18H). 13C NMR
276.8 Hz), 122.9 (d, J ¼ 3.1 Hz), 83.4, 37.0 (q, J ¼ 30.0 Hz), 28.6. 19
F
(101 MHz, CDCl3):
d
168.1, 133.9, 125.8 (q, J ¼ 276.3 Hz), 120.4 (d, J ¼
NMR (376 MHz, CDCl3):
d
ꢁ66.08 (t, J ¼ 10.6 Hz). FT-IR (KBr, in
3.3 Hz), 81.6, 53.3, 37.2 (q, J ¼ 29.8 Hz), 31.5, 27.8. 19F NMR
cmꢁ1): 3093, 2904, 1577, 1475, 1429, 1397, 1334, 1321, 1296, 1261,
1247, 1215, 1198, 1176, 1089, 1057, 1012, 762, 711, 655. HRMS (ESI-
TOF) m/z: [M ꢁ H]þ calcd for C18H14Cl2F3O4S2 484.9688; Found:
484.9677.
(376 MHz, CDCl3):
d
ꢁ66.46 (t, J ¼ 10.7 Hz). FT-IR (KBr, in cm-1):
2982, 2935, 1728, 1481, 1460, 1433, 1395, 1371, 1344, 1255, 1140,
1058, 971, 848, 745, 646. HRMS (ESI-TOF) m/z: [M þ Na]þcalcd for
C
16H25F3O4Na 361.1597; Found: 361.1591.
3.5.7. (E)-4,4'-(6,6,6-Trifluorohex-3-ene-1,1-diyldisulfonyl)
bis(methylbenzene) (2g)
3.5.2. (E)-Dimethyl-2-(5,5,5-trifluoropent-2-en-1-yl)malonate (2b)
Colorless liquid, dr (1 : 27); (58.6 mg, yield 77%); 1H NMR
Semi solid, dr (1 : 11); (57 mg, yield 85%); 1H NMR (400 MHz,
(400 MHz, CDCl3):
d
5.73e5.60 (m,1H), 5.49 (dt, J ¼ 15.2, 7.0 Hz,1H),
CDCl3):
d
7.82 (d, J ¼ 8.3 Hz, 4H), 7.36 (d, J ¼ 8.1 Hz, 4H), 5.85e5.63
3.72 (s, 6H), 3.44 (t, J ¼ 7.5 Hz, 1H), 2.75 (qd, J ¼ 10.7, 7.4 Hz, 2H),
2.64 (t, J ¼ 7.1 Hz, 2H). 13C NMR (101 MHz, CDCl3):
d 169.0, 133.2,
(m,1H), 5.42e5.29 (m,1H), 4.40 (t, J ¼ 5.8 Hz,1H), 2.90 (t, J ¼ 6.5 Hz,
2H), 2.81e2.64 (m, 2H), 2.46 (s, 6H). 13C NMR (101 MHz, CDCl3):
125.7 (q, J ¼ 276.6 Hz), 121.3 (d, J ¼ 3.5 Hz), 52.5, 51.2, 37.2 (q, J ¼
29.8 Hz), 31.7. 19F NMR (376 MHz, CDCl3):
d
ꢁ66.56 (t, J ¼ 10.7 Hz).
d
146.1, 146.0, 134.7, 131.8, 129.8, 129.7, 129.7, 129.6, 125.6 (q, J ¼
FT-IR (KBr, in cmꢁ1): 1737, 1436, 1402, 1261, 1146, 605. HRMS (ESI-
TOF) m/z: [M þ H]þ calcd for C10H14F3O4 255.0839; Found:
255.0839.
276.7 Hz), 122.3 (d, J ¼ 3.2 Hz), 83.3, 37.0 (q, J ¼ 29.9 Hz), 28.8, 21.7.
19F NMR (376 MHz, CDCl3):
d
ꢁ66.16 (t, J ¼ 10.6 Hz). FT-IR (KBr, in
cmꢁ1): 3103, 3072, 3011, 2944, 2843, 1597, 1579, 1497, 1464, 1443,
1416, 1332, 1301, 1266, 1151, 1080, 1050, 1022, 971, 863, 805, 764,
724, 703, 674, 625. HRMS (ESI-TOF) m/z: [M þ H]þ calcd for
3.5.3. (E)-Diethyl-2-(5,5,5-trifluoropent-2-en-1-yl)malonate (2c)
Colorless oil, dr (1 : 22); (70.1 mg, yield 83%); 1H NMR (400 MHz,
C
20H22F3O4S2 447.0906; Found: 447.0901.
CDCl3):
d
5.75e5.57 (m, 1H), 5.59e5.31 (m, 1H), 4.18 (qd, J ¼ 7.2,
2.3 Hz, 4H), 3.39 (t, J ¼ 7.5 Hz, 1H), 2.75 (qd, J ¼ 10.6, 7.3 Hz, 2H),
3.5.8. (E)-4,4'-(6,6,6-Trifluorohex-3-ene-1,1-diyldisulfonyl)
bis(methoxybenzene (2h)
2.64 (t, J ¼ 7.2 Hz, 2H), 1.25 (t, J ¼ 7.2 Hz, 6H). 13C NMR (101 MHz,
CDCl3):
d
168.7, 133.4, 125.7 (q, J ¼ 276.4 Hz), 121.0 (d, J ¼ 3.5 Hz),
White solid, (mp: 97e98 ꢂC), dr (1 : 12); (58.1 mg, yield 81%); 1H
61.5, 51.5, 37.2 (q, J ¼ 29.8 Hz), 31.6, 14.0. 19F NMR (376 MHz, CDCl3):
NMR (400 MHz, CDCl3):
d
7.87 (d, J ¼ 9.0 Hz, 4H), 7.01 (d, J ¼ 9.0 Hz,
d
ꢁ66.54 (t, J ¼ 10.7 Hz). FT-IR (KBr, in cmꢁ1): 3099, 3034, 2983,
4H), 5.95e5.62 (m, 1H), 5.52e5.24 (m, 1H), 4.37 (t, J ¼ 5.9 Hz, 1H),
2932, 2874, 1722, 1643, 1597, 1496, 1479, 1459, 1437, 1397, 1370,
3.90 (s, 6H), 2.89 (t, J ¼ 6.3 Hz, 2H), 2.81e2.68 (m, 2H). 13C NMR
1325, 1082, 1015, 878, 668. HRMS (ESI-TOF) m/z: [M þ H]þcalcd for
(101 MHz, CDCl3):
d
164.5,132.0,132.0,128.9,125.6 (q, J ¼ 276.6 Hz),
C
12H18F3O4 283.1152; Found: 283.1148.
122.1 (d, J ¼ 3.1 Hz),114.4,114.3, 83.5, 55.7, 37.0 (q, J ¼ 29.9 Hz), 29.0.
19F NMR (376 MHz, CDCl3):
d
ꢁ66.13 (t, J ¼ 10.7 Hz). FT-IR (KBr, in
3.5.4. (E)-Diisopropyl-2-(5,5,5-trifluoropent-2-en-1-yl)malonate
(2d)
cmꢁ1): 3103, 3072, 3011, 2944, 2843, 1597, 1579, 1497, 1464, 1443,
1416, 1332, 1301, 1266, 1151, 1080, 1050, 1022, 971, 863, 805, 764,
724, 703, 674, 625. HRMS (ESI-TOF) m/z: [M þ H]þ calcd for
Colorless oil, dr (1 : 22); (75.3 mg, yield 81%); 1H NMR (400 MHz,
CDCl3):
d
5.76e5.63 (m, 1H), 5.48 (dt, J ¼ 15.3, 3.9 Hz,1H), 5.10e4.98
C20H22F3O6S2 479.0804; Found: 479.0799.
Please cite this article as: P. Chandu et al., Photoredox catalysed allylic trifluoromethylation via ring opening of vinyl cyclopropanes using
Langlois reagent, Tetrahedron, https://doi.org/10.1016/j.tet.2019.130641

8
P. Chandu et al. / Tetrahedron xxx (xxxx) xxx
3.5.9. (E)-Methyl-7,7,7-trifluoro-2-(phenylsulfonyl)hept-4-enoate
(2i)
3.5.14. (E)-Ethyl-2-cyano-7,7,7-trifluorohept-4-enoate (2n)
Colorless oil, dr (1 : 10); (57.2 mg, yield 85%); 1H NMR (400 MHz,
Colorless oil, dr (1 : 10); (39.8 mg, yield 79%); 1H NMR (400 MHz,
CDCl3):
d
5.76e5.66 (m, 1H), 5.66e5.54 (m, 1H), 4.22 (q, J ¼ 7.3 Hz,
CDCl3):
7.8 Hz, 2H), 5.63e5.44 (m, 2H), 4.00 (dd, J ¼ 11.4, 3.9 Hz,1H), 3.63 (s,
3H), 2.88e2.50 (m, 4H). 13C NMR (101 MHz, CDCl3):
165.6, 136.8,
d
7.87 (d, J ¼ 7.4 Hz, 2H), 7.70 (t, J ¼ 7.7 Hz, 1H), 7.58 (t, J ¼
2H), 3.55 (t, J ¼ 6.6 Hz, 1H), 2.86e2.73 (m, 2H), 2.66 (t, J ¼ 6.8 Hz,
2H), 1.27 (t, J ¼ 7.2 Hz, 3H). 13C NMR (101 MHz, CDCl3):
d 165.2,
d
130.6, 125.5 (q, J ¼ 276.6 Hz), 123.4 (d, J ¼ 3.1 Hz), 115.8, 62.8, 37.2,
134.5, 130.9, 129.3, 129.2, 129.1, 125.5 (q, J ¼ 276.4 Hz), 122.8 (d, J ¼
36.9 (q, J ¼ 30.1 Hz), 32.4, 13.7. 19F NMR (376 MHz, CDCl3):
ꢁ66.46
d
3.4 Hz), 69.9, 52.9, 37.1 (q, J ¼ 29.9 Hz), 29.8. 19F NMR (376 MHz,
(t, J ¼ 10.6 Hz). FT-IR (KBr, in cmꢁ1): 2988, 2940, 2252, 1746, 1620,
1432, 1371, 1340, 1253, 1211, 1140, 1057, 975, 911, 854, 648. HRMS
(ESI-TOF) m/z: [M þ H]þ calcd for C10H13F3NO2 236.0893; Found:
236.0890.
CDCl3):
d
ꢁ66.45 (t, J ¼ 10.6 Hz). FT-IR (KBr, in cmꢁ1): 2987, 1741,
1641, 1447, 1372, 1326, 1270, 1204, 1139, 1084, 1057, 1036, 974, 916,
861, 841, 761, 741, 723, 689, 649. HRMS (ESI-TOF) m/z: [M þ H]þ
calcd for C14H16F3O4S 337.0716; Found: 337.0710.
3.5.15. (E)-2-(5,5,5-Trifluoropent-2-en-1-yl)malononitrile (2o)
Colorless liquid, dr (1 : 8); (47.4 mg, yield 84%);1H NMR
3.5.10. (E)-tert-Butyl-7,7,7-trifluoro-2-tosylhept-4-enoate (2j)
Colorless oil, dr (1: 0.39); (42.7 mg, yield 73%); 1H NMR
(400 MHz, CDCl3):
d
5.87e5.74 (m, 2H), 3.79 (t, J ¼ 6.6 Hz, 1H),
2.99e2.84 (m, 2H), 2.78 (t, J ¼ 6.1 Hz, 2H). 13C NMR (101 MHz,
(400 MHz, CDCl3):
d
7.75 (d, J ¼ 8.3 Hz, 2H), 7.36 (d, J ¼ 8.1 Hz, 2H),
CDCl3):
d
128.2, 126.4 (d, J ¼ 3.3 Hz), 125.3 (q, J ¼ 276.6 Hz), 111.8,
5.65e5.54 (m, 1H), 5.54e5.44 (m, 1H), 3.87 (dd, J ¼ 11.4, 3.8 Hz, 1H),
37.1 (q, J ¼ 30.3 Hz), 33.6, 22.9. 19F NMR (376 MHz, CDCl3):
ꢁ66.14
d
2.81e2.57 (m, 4H), 2.46 (s, 3H), 1.34 (s, 9H). 13C NMR (101 MHz,
(t, J ¼ 10.5 Hz). FT-IR (KBr, in cmꢁ1): 2921, 2258, 1721, 1431, 1373,
1343, 1325, 1254, 1212, 1186, 1143, 1059, 976, 911, 845, 649. HRMS
(ESI-TOF) m/z: [M ꢁ H]þ calcd for C8H6F3N2 187.0489; Found:
187.0481.
CDCl3):
d
164.1, 145.4, 134.1, 131.3, 129.6, 129.4, 125.6 (q, J ¼
276.6 Hz), 122.3 (d, J ¼ 3.4 Hz), 37.2 (q, J ¼ 29.9 Hz). 83.5, 70.4, 37.2
(q, J ¼ 29.9 Hz), 29.8, 27.6, 21.7. 19F NMR (376 MHz, CDCl3):
ꢁ66.31
d
(t, J ¼ 10.6 Hz). FT-IR (KBr, in cmꢁ1): 2975, 2932, 1727, 1599, 1573,
1493, 1456, 1395, 1369, 1319, 1260, 1140, 1111, 1083, 1015, 843, 813,
709, 665, 583. HRMS (ESI-TOF) m/z: [M ꢁ H]þ calcd for C18H22F3O4S
391.1196; Found: 391.1204.
3.5.16. (E)-2,2-Dimethyl-5-(5,5,5-trifluoropent-2-en-1-yl)-1,3-
dioxane-4,6-dione (2p)
White solid, (m.p: 102e104 ꢂC), dr (1 : 99); (30.9 mg, yield 77%);
1H NMR (400 MHz, CDCl3):
d
5.83e5.69 (m, 1H), 5.67e5.57 (m, 1H),
3.59 (t, J ¼ 5.1 Hz,1H), 2.88e2.84 (m, 2H), 2.83e2.70 (m, 2H),1.78 (s,
3H), 1.74 (s, 3H). 13C NMR (101 MHz, CDCl3):
164.7, 131.8, 125.7 (d,
J ¼ 276.4 Hz), 123.1 (d, J ¼ 3.4 Hz), 105.1, 46.1, 37.2 (q, J ¼ 29.8 Hz),
3.5.11. (E)-Dibenzyl-2-(5,5,5-trifluoropent-2-en-1-yl)malonate
(2k)
d
Colourless oil, dr (1 : 8); (47.5 mg, yield 78%); 1H NMR (400 MHz,
CDCl3): d 7.39e7.27 (m, 10H), 5.71e5.58 (m, 1H), 5.52e5.39 (m, 1H),
29.0, 28.3, 26.8. 19F NMR (376 MHz, CDCl3):
d
ꢁ66.36 (t, J ¼ 10.7 Hz).
5.16 (d, J ¼ 2.1 Hz, 4H), 3.55 (t, J ¼ 7.4 Hz, 1H), 2.76e2.62 (m, 4H). 13
C
FT-IR (KBr, in cmꢁ1): 3446, 3098, 3016, 3004, 2988, 1978, 1923,
1874, 1733, 1634, 1584, 1421, 1307, 1205, 1164, 1085, 1065, 1020, 989,
883, 826, 795, 689, 666. HRMS (ESI-TOF) m/z: [M ꢁ H]þ calcd for
NMR (101 MHz, CDCl3):
d 168.3, 135.2, 133.0, 128.5, 128.4, 128.2,
125.7 (q, J ¼ 276.7 Hz), 121.3 (d, J ¼ 3.5 Hz), 67.2, 51.5, 37.1 (q, J ¼
29.7 Hz), 31.6. 19F NMR (376 MHz, CDCl3):
d
ꢁ66.39 (t, J ¼ 10.6 Hz).
C
11H12F3O4 265.0693; Found: 265.0695.
FT-IR (KBr, in cmꢁ1): 3089, 3066, 2915, 1728, 1671, 1638, 1596, 1446,
1320, 1289, 1208, 1159, 1144, 1084, 755, 724, 688, 665. HRMS (ESI-
TOF) m/z: [M þ H]þ calcd for C22H22F3O4 407.1470; Found:
407.1468.
3.5.17. (E)-2-(5,5,5-Trifluoropent-2-en-1-yl)-1H-indene-1,3(2H)-
dione (2q)
Colorless oil, dr (1 : 32); (28.5 mg, yield 71%);1H NMR (400 MHz,
CDCl3):
d
7.96 (dd, J ¼ 5.7, 3.1 Hz, 2H), 7.84 (dd, J ¼ 5.7, 3.1 Hz, 2H),
3.5.12. (E)-Methyl-2-benzoyl-7,7,7-trifluorohept-4-enoate (2l)
5.70e5.60 (m, 1H), 5.55e5.45 (m, 1H), 3.10 (t, J ¼ 5.8 Hz, 1H), 2.74 (t,
Colorless oil, dr (1 : 8); (37.3 mg, yield 83%); 1H NMR (400 MHz,
J ¼ 6.5 Hz, 2H), 2.65 (qd, J ¼ 10.6, 7.2 Hz, 2H). 13C NMR (101 MHz,
CDCl3):
d
7.96 (dd, J ¼ 8.3, 1.3 Hz, 2H), 7.57 (dd, J ¼ 9.1, 5.3 Hz, 1H),
CDCl3):
d
199.9, 142.5, 135.7, 132.3, 125.6 (q, J ¼ 276.5 Hz), 123.2,
121.9 (d, J ¼ 3.3 Hz), 53.1, 37.1 (q, J ¼ 29.8 Hz), 29.4. 19F NMR
7.46 (t, J ¼ 7.7 Hz, 2H), 5.78e5.62 (m, 1H), 5.61e5.38 (m, 1H), 4.41 (t,
J ¼ 7.2 Hz, 1H), 3.65 (s, 3H), 2.81e2.62 (m, 4H). 13C NMR (101 MHz,
(376 MHz, CDCl3):
d
ꢁ66.60 (t, J ¼ 10.7 Hz). FT-IR (KBr, in cmꢁ1):
CDCl3):
d
194.1, 169.6, 135.9, 133.7, 133.6, 128.7, 128.5, 125.7 (d, J ¼
3101, 2978, 2930, 1723, 1646, 1460, 1433, 1396, 1369, 1323, 1260,
1210, 1016, 991, 948, 921, 669. HRMS (ESI-TOF) m/z: [M ꢁ H]þ calcd
for C14H10F3O2 267.0638; Found: 267.0641.
276.5 Hz), 120.9 (d, J ¼ 3.5 Hz), 53.4, 52.4, 37.0 (q, J ¼ 29.8 Hz), 31.8.
19F NMR (376 MHz, CDCl3):
d
ꢁ66.51 (t, J ¼ 10.7 Hz). FT-IR (KBr, in
cmꢁ1): 3034, 2981, 2933, 1720, 1644, 1599, 1497, 1434, 1397, 1369,
1325, 1288, 1211, 1132, 1081, 1016, 988, 949, 904, 877, 841, 818, 731,
706, 668. HRMS (ESI-TOF) m/z: [M þ H]þ calcd for C15H16F3O3
301.1046; Found: 301.1043.
3.5.18. (Z)-Dimethyl-2-(4-(trifluoromethyl)cyclopent-2-en-1-yl)
malonate (2r)
Colorless liquid, 1H NMR (400 MHz, CDCl3):
d
5.99 (d, J ¼ 4.6 Hz,
1H), 5.75e5.70 (m, 1H), 3.75 (s, 3H), 3.74 (s, 3H), 3.60e3.51 (m, 1H),
3.47e3.38 (m, 1H), 3.34 (d, J ¼ 8.5 Hz, 1H), 2.33e2.21 (m, 1H), 1.94
3.5.13. (E)-2-Benzoyl-7,7,7-trifluorohept-4-ene-nitrile (2m)
Colorless oil, dr (1 : 8); (55.3 mg, yield 69%); 1H NMR (400 MHz,
(ddd, J ¼ 14.5, 8.5, 5.5 Hz, 1H). 13C NMR (101 MHz, CDCl3):
d 168.6,
CDCl3):
7.7 Hz, 2H), 5.84e5.72 (m, 1H), 5.70e5.56 (m, 1H), 4.38 (dd, J ¼ 7.9,
6.1 Hz, 1H), 2.93e2.69 (m, 4H). 13C NMR (101 MHz, CDCl3):
189.8,
d
7.96 (d, J ¼ 1.6 Hz, 2H), 7.67 (t, J ¼ 7.9 Hz, 1H), 7.53 (t, J ¼
168.5, 137.7, 127.1 (d, J ¼ 278.5 Hz), 127.0 (d, J ¼ 2.4 Hz), 55.9, 52.6,
49.4 (d, J ¼ 28.6 Hz), 44.9, 29.7, 28.0. 19F NMR (376 MHz, CDCl3):
d
d
ꢁ72.82 (d, J ¼ 8.7 Hz). FT-IR (KBr, in cmꢁ1): 1733, 1400, 1119, 601.
134.9, 134.9, 134.0, 131.3, 129.3, 128.9, 125.7 (q, J ¼ 276.5 Hz), 123.5
HRMS (ESI-TOF) m/z: [M þ H]þ calcd for C11H14F3O4 267.0839;
(d, J ¼ 3.4 Hz), 116.7, 39.5, 37.3 (q, J ¼ 30.0 Hz), 32.4. 19F NMR
Found: 267.0834.
(376 MHz, CDCl3):
d
ꢁ66.27 (t, J ¼ 10.6 Hz). FT-IR (KBr, in cmꢁ1):
3433, 3094, 3023, 2933, 2864, 1743, 1720, 1589, 1432, 1372, 1334,
1269, 1242, 1126, 1056, 971, 915, 842, 801, 743, 687, 651. HRMS (ESI-
TOF) m/z: [M ꢁ H ]þ calcd for C14H11F3NO 266.0798; Found:
266.0802.
3.5.19. (Z)-Dimethyl-2-4-(trifluoromethyl)cyclohex-2-en-1-yl)
malonate(2s)
Colorless liquid, 1H NMR (400 MHz, CDCl3):
d
5.83 (d, J ¼ 10.3 Hz,
1H), 5.70 (d, J ¼ 10.0 Hz, 1H), 3.74 (s, 3H), 3.74 (s, 3H), 3.30 (d, J ¼
Please cite this article as: P. Chandu et al., Photoredox catalysed allylic trifluoromethylation via ring opening of vinyl cyclopropanes using
Langlois reagent, Tetrahedron, https://doi.org/10.1016/j.tet.2019.130641

P. Chandu et al. / Tetrahedron xxx (xxxx) xxx
9
8.2 Hz, 1H), 3.00e2.79 (m, 1H), 2.08e1.87 (m, 1H), 1.63 (dd, J ¼ 10.7,
2.4 Hz, 2H), 1.40 (tdd, J ¼ 13.1, 10.6, 2.6 Hz, 2H). 13C NMR (101 MHz,
276.7 Hz), 120.8 (d, J ¼ 3.2 Hz), 63.7, 37.3 (q, J ¼ 29.6 Hz), 37.1, 31.4,
20.8. 19F NMR (376 MHz, CDCl3):
d
ꢁ66.61 (t, J ¼ 10.7 Hz). FT-IR (KBr,
CDCl3):
d
168.4, 168.4, 132.5, 126.9 (q, J ¼ 279.0 Hz), 122.6 (d, J ¼
in cmꢁ1): 1736, 1403, 1134, 603. HRMS (ESI-TOF) m/z: [M þ H]þ
2.8 Hz), 40.4 (q, J ¼ 27.3 Hz), 56.0, 52.5, 35.3, 24.9, 21.3. 19F NMR
calcd for C12H18F3O4 283.1152; Found: 283.1149.
(376 MHz, CDCl3):
d
ꢁ72.94 (d, J ¼ 8.7 Hz). FT-IR (KBr, in cmꢁ1):
1739, 1435, 1338, 1253, 1151, 605. HRMS (ESI-TOF) m/z: [M þ H]þ
Declaration of competing interest
There are no conflicts to declare.
Acknowledgements
calcd for C12H16F3O4 281.0995; Found: 281.0997.
3.5.20. (Z)-Dimethyl-2-(4-(trifluoromethyl)cyclooct-2-en-1-yl)
malonate (2t)
Colorless liquid, 1H NMR (400 MHz, CDCl3):
d
5.68 (dd, J ¼ 12.1,
6.1 Hz, 1H), 5.50 (ddd, J ¼ 12.2, 6.9, 1.2 Hz, 1H), 3.73 (s, 3H), 3.72 (s,
Financial support from the IISER Kolkata (startup Grant), SERB
(Early Carrier Research (ECR) Grant) and DST-SERB (Ramanujan
Fellowship) are acknowledged. PC, KGG and DD thank UGC, DSTand
IISER Kolkata for their Ph.D fellowship.
3H), 3.42 (d, J ¼ 7.1 Hz, 1H), 3.39e3.18 (m, 2H), 1.93e1.60 (m, 8H).
13C NMR (101 MHz, CDCl3):
d
168.8, 168.6, 133.2, 127.4 (q, J ¼
279.3 Hz), 123.6 (d, J ¼ 2.4 Hz), 57.2, 52.5, 43.0 (q, J ¼ 25.8 Hz).39.5,
29.7, 29.5, 25.5, 25.5, 23.8. 19F NMR (376 MHz, CDCl3):
d
ꢁ72.63 (d,
J ¼ 8.8 Hz). FT-IR (KBr, in cmꢁ1): 1738, 1434, 1394, 1265, 1165, 606.
HRMS (ESI-TOF) m/z: [M þ H]þ calcd for C14H20F3O4 309.1308;
Found: 309.1300.
Appendix A. Supplementary data
Supplementary data to this article can be found online at
https://doi.org/10.1016/j.tet.2019.130641.
3.5.21. (E)-4,4'-(((2-(5,5,5-Trifluoropent-2-en-1-yl)propane-1,3-
diyl)bis(oxy))bis(methylene)) bis((trifluoromethyl)benzene) (2u)
Colorless liquid, dr (1 : 37); (64.1 mg, yield 83%); 1H NMR
References
[1] V. Ganesh, S. Chandrasekaran, Synthesis 48 (2016) 4347e4380.
[2] (a) I. Shimizu, Y. Ohashi, J. Tsuji, Tetrahedron Lett. 26 (1985) 3825e3828;
(b) S.D. Benjamin, A. Furstner, Chem. Commun. 46 (2009) 7116e7118.
[3] (a) C.-F. Li, W.-J. Xiao, Jing, H. Alper, J. Org. Chem. 74 (2009) 888e890;
(b) J. Yin, C.J.T. Hyland, J. Org. Chem. 80 (2015) 6529e6536;
(c) S. Sebelius, V.J. Olsson, O.A. Wallner, K.J. Szabo, J. Am. Chem. Soc. 128
(2006) 8150e8151.
[4] (a) M. Meazza, H. Guo, R. Rios, Org. Biomol. Chem. 15 (2017) 2479e2490;
(b) K.S. Feldman, A.L. Romanelli, R.E. Ruckle, R.F. Miller, J. Am. Chem. Soc. 110
(1988) 3300e3302;
(c) O. Andrey, C.-D. Boris, L. Chabaud, K. Julienne, Y. Landais, P.R. Liliana,
P. Renaud, Tetrahedron 59 (2003) 8543e8550.
[5] A. Ogawa, I. Ogawa, R. Obayashi, K. Umezu, M. Doi, T. Hirao, J. Org. Chem. 64
(1999) 86e92.
[6] R. Leki, Y. Kani, S. Tsunoi, I. Shibata, Chem. Eur. J. 21 (2015) (2015) 6295e6300.
[7] G. Pattenden, M.A. Gonzalez, S. Muculloch, A. Walter, S.I. Woodhead, J. Proc.
Natl. Acad. Sci. USA 101 (2004) 12024e12029.
[8] S. Purser, P.R. Moore, S. Swallow, V. Gouverneur, Chem. Soc. Rev. 37 (2008)
320e330.
[9] W.K. Hagmann, J. Med. Chem. 51 (2008) 4359e4369.
[10] (a) M. Shimizu, T. Hiyama, Angew. Chem. Int. Ed. 44 (2005) 214e231;
(b) K. Muller, C. Faeh, F. Diederich, Science 317 (2007) 1881e1886.
[11] A. Studer, Angew. Chem. Int. Ed. 51 (2012) 8950e8958.
[12] a) Y. Wang, L. Truesdale, J.Q. Yu, J. Am. Chem. Soc. 132 (2010) 3648e3649;
(b) A. Hafner, S. Brase, Angew. Chem. Int. Ed. 124 (2012) 3773e3775;
(c) A. Hafner, S. Brase, Angew. Chem. Int. Ed. 51 (2012) 3713e3715;
(d) X. Mu, S. Chen, X. Zhen, X. Liu, Chem. Eur. J. 17 (2011) 6039e6042;
(e) Y. Ye, S.H. Lee, M.S. Sanford, Org. Lett. 13 (2011) 5464e5467;
(f) X.-G. Zhang, H.-X. Dai, M. Wasa, J.-Q. Yu, J. Am. Chem. Soc. 134 (2012)
11948e11951;
(400 MHz, CDCl3):
d
7.59 (d, J ¼ 8.1 Hz, 4H), 7.42 (d, J ¼ 8.0 Hz, 4H),
5.77e5.60 (m, 1H), 5.50e5.32 (m, 1H), 4.54 (s, 4H), 3.56e3.46 (m,
4H), 2.82e2.67 (m, 2H), 2.23 (t, J ¼ 7.0 Hz, 2H), 2.05 (dt, J ¼ 12.5,
6.3 Hz, 1H). 13C NMR (101 MHz, CDCl3):
d 142.6, 135.7, 127.4, 126.0
(q, J ¼ 277.7 Hz), 125.5 (q, J ¼ 276 Hz), 125.3(d, J ¼ 3.6 Hz), 119.8 (d,
J ¼ 3.2 Hz), 72.3, 70.4, 39.3, 37.3 (d, J ¼ 29.6 Hz), 31.7. 19F NMR
(471 MHz, CDCl3):
d
ꢁ62.54 (6F, s), ꢁ66.65 (3F, t, J ¼ 10.1 Hz). FT-IR
(KBr, in cmꢁ1): 1406, 1329, 1253, 1134, 601. HRMS (ESI-TOF) m/z:
[M þ H]þ calcd for C24H24F9O2 515.1627; Found: 515.1628.
3.5.22. (E)-2-(5,5,5-Trifluoropent-2-en-1-yl)propane-1,3-
diylbis(2,2-dimethylpropanoate)) (2v)
Colorless liquid, dr (1 : 6); (39.5 mg, yield 72%); 1H NMR
(400 MHz, CDCl3):
J ¼ 11.1, 5.4 Hz, 4H), 2.88e2.69 (m, 2H), 2.25e2.07 (m, 3H), 1.19 (s,
18H). 13C NMR (126 MHz, CDCl3):
178.3, 134.3, 126.1 (q,
280.78 Hz), 120.8 (d, J ¼ 3.6 Hz). 63.3, 37.3, 38.8,37.3 (q, 24.24 Hz),
d 5.73e5.63 (m, 1H), 5.49e5.40 (m, 1H), 4.03 (qd,
d
31.5, 27.1. 19F NMR (376 MHz, CDCl3):
d
ꢁ66.62 (t, J ¼ 10.7 Hz). FT-IR
(KBr, in cmꢁ1): 1734, 1411, 1387, 1164, 1077, 600. HRMS (ESI-TOF) m/
z: [M þ H]þ calcd for C18H30F3O4 367.2091; Found: 367.2082.
3.5.23. (E)-2-(5,5,5-Trifluoropent-2-en-1-yl)propane-1,3-diyl-
dibenzoate (2w)
Colorless liquid, dr (1 : 7); (47.5 mg, yield 78%); 1H NMR
(g) Y. Ye, M.S. Sanford, J. Am. Chem. Soc. 134 (2012) 9034e9037.
[13] a) M. Paeth, W. Carson, J.-H. Luo, D. Tierney, Z. Cao, M.-J. Cheng, W. Liu, Chem.
Eur. J. 24 (2018) 11559e11563;
(400 MHz, CDCl3):
d
8.03 (d, J ¼ 7.6 Hz, 4H), 7.56 (t, J ¼ 7.5 Hz, 2H),
7.43 (t, J ¼ 7.7 Hz, 4H), 5.83e5.73 (m, 1H), 5.60e5.47 (m, 1H), 4.43
(ddd, J ¼ 25.4, 11.3, 5.6 Hz, 4H), 2.89e2.71 (m, 2H), 2.43 (ddd, J ¼
11.2, 7.8, 3.3 Hz, 1H), 2.37 (t, J ¼ 7.0 Hz, 2H). 13C NMR (101 MHz,
(b) S. Guo, D.I. Abusalim, S.P. Cook, J. Am. Chem. Soc. 140 (2018)
12378e12382;
(c) Z. Liu, H. Xiao, B. Zhang, H. shen, L. Zhu, C. Li, Angew. Chem. Int. Ed. 58
(2019) 2510e2513.
CDCl3):
d
166.4, 134.3, 133.1, 129.9, 129.6, 128.4, 125.8 (q, J ¼
[14] (a) J.M. Larsson, S.R. Pathipati, K.J. Szabo, J. Org. Chem. 78 (2013) 7330e7336;
(b) C. Isanbor, D.O. Hagan, J. Fluorine Chem. 127 (2006) 303e319.
[15] (a) A.T. Parsons, S.L. Buchwald, Angew. Chem. Int. Ed. 50 (2011) 9120e9123;
(b) J. Xu, Y. Fu, D.F. Luo, Y.Y. Jiang, B. Xiao, Z.J. Liu, T.J. Gong, L. Liu, J. Am. Chem.
Soc. 133 (2011) 15300.
[16] (a) Z.-R. Li, X.-X. Bao, J. Sun, J. Shen, D.-Q. Wu, Y.-K. Liu, Q.-H. Deng, F. Liu, Org.
Chem. Front. 3 (2016) 934e938;
(b) P. Chandu, K.G. Ghosh, D.S. Kumar, J. Org. Chem. 84 (2019) 8771e8781.
[17] (a) P. Xu, A. Abdukader, K. Hu, Y. Chenga, C. Zhu, Chem. Commun. 50 (2014)
2308e2310;
276.7 Hz), 121.0 (d, J ¼ 3.4 Hz), 64.4, 37.6, 37.3 (q, J ¼ 29.8 Hz), 31.7.
19F NMR (376 MHz, CDCl3):
d
ꢁ66.43 (t, J ¼ 10.7 Hz). FT-IR (KBr, in
cmꢁ1): 3065, 3034, 2956, 2897, 2853, 1723, 1603, 1586, 1493, 1451,
1375, 1314, 1270, 1175, 1135, 1111, 1069, 1025, 971, 842, 802, 710,
688, 651. HRMS (ESI-TOF) m/z: [M þ Na]þ calcd for C22H21F3O4Na
429.1284; Found: 429.1279.
(b) Q. Wei, J.-R. Chen, X.-Q. Hu, X.-C. Yang, B. Lu, W.-J. Xiao, Org. Lett. 17
(2015) 4464e4467;
(c) D.J. Wilger, N.J. Gesmundo, D.A. Nicewicz, Chem. Sci. 4 (2013) 3160e3165;
(d) N. Iqbal, G.J. Jun, S. Park, E.J. Cho, Angew. Chem. Int. Ed. 53 (2014)
539e542;
(e) D.A. Nagib, D.W.C. Macmillan, Nature 480 (2011) 224e228;
(f) J.W. Beatty, J.J. Douglas, K.P. Cole, C.R.J. Stephenson, Nat. Commun. 6 (2015)
7919e7924.
3.5.24. (E)-2-(5,5,5-Trifluoropent-2-en-1-yl)propane-1,3-diyl-
diacetate (2x)
Colorless liquid, dr (1 : 8); (30.3 mg, yield 71%); 1H NMR
(400 MHz, CDCl3):
J ¼ 11.2, 5.6 Hz, 4H), 3.05e2.41 (m, 2H),2.20e2.08 (m, 3H), 2.06 (s,
6H). 13C NMR (101 MHz, CDCl3):
170.9, 134.3, 125.8 (q, J ¼
d 5.79e5.58 (m, 1H), 5.57e5.33 (m, 1H), 4.05 (qd,
d
Please cite this article as: P. Chandu et al., Photoredox catalysed allylic trifluoromethylation via ring opening of vinyl cyclopropanes using
Langlois reagent, Tetrahedron, https://doi.org/10.1016/j.tet.2019.130641

10
P. Chandu et al. / Tetrahedron xxx (xxxx) xxx
[18] (a) J.-B. Tommasion, A. Brondex, M. Medebielle, M. Thomalla, B.R. Langolis,
T. Billard, Synlett 10 (2002) 1697e1699;
(b) H.-T. Qin, S.-W. Wu, J.-L. Liu, F. Liu, Chem. Commun. 53 (2017) 1696e1699.
[19] K. Kalyanasundaram, Coord. Chem. Rev. 46 (1982) 159e244.
[20] J.D. Slinker, A.A. Gorosetsky, M.S. Lowry, J. Wang, S. Parker, R. Rohl, S. Berhard,
G.G. Malliaras, J. Am. Chem. Soc. 126 (2004) 2763e2767.
[23] (a) A.J. Perkowski, D.A. Nicewicz, J. Am. Chem. Soc. 135 (2013) 10334e10337;
(b) N.A. Romero, D.A. Nicewicz, J. Am. Chem. Soc. 136 (2014) 17024e17035;
(c) P.D. Morse, D.A. Nicewicz, Chem. Sci. 6 (2015) 270e274.
[24] A. Ur-Rhaman, Studies in Natural Products Chemistry, first ed., Elsevier, 2012.
[25] W.L.F. Armarego, C.L.L. Chai, Purification of Laboratory Chemicals, ISBN: 0-
7506-7571-3.
[21] L. Flamigni, A. Barbieri, C. Sabatini, B. Ventura, F. Barigelletti, Top. Curr. Chem.
281 (2007) 143e203.
[26] A.P. Dieskau, M.S. Holzwarth, B. Plietker, J. Am. Chem. Soc. 134 (2012)
5048e5051.
[22] M.S. Lowry, J.I. Goldsmith, J.D. Slinker, R. Rohl, R.A. Pascal, G.G. Malliaras,
S. Bernhard, Chem. Mater. 17 (2005) 5712e5719.
[27] A. singh, K. Teegardin, M. Kelly, K.S. Prasad, S. Krishnan, J.D. Weaver,
J. Organomet. Chem. 776 (2015) 51e59.
Please cite this article as: P. Chandu et al., Photoredox catalysed allylic trifluoromethylation via ring opening of vinyl cyclopropanes using
Langlois reagent, Tetrahedron, https://doi.org/10.1016/j.tet.2019.130641