Metal- and additive-free cascade trifluoroethylation/cyclization of organic isoselenocyanates by phenyl(2,2,2-trifluoroethyl)iodonium triflate

Article abstract of DOI:10.1016/j.jfluchem.2019.109360

A novel and convenient cascade trifluoroethylation/cyclization of organic isoselenocyanates by phenyl(2,2,2-trifluoroethyl)iodonium triflate is reported. A series of 2-isoselenocyanobiaryls and aryl alkyl isoselenocyanates reacted with phenyl(2,2,2-trifluoroethyl)iodonium triflate in CH₂Cl₂ at 40 °C under metal- and additive-free conditions for 3 h to provide the corresponding trifluoroethylselenolated phenanthridines and 3,4-dihydroisoquinoline derivatives in good to excellent yields. The reaction represents the first general approach to access trifluoroethylselenolated phenanthridines and 3,4-dihydroisoquinolines from organic isoselenocyanates.

Full text of DOI:10.1016/j.jfluchem.2019.109360

JournalofFluorineChemistry226(2019)109360
Contents lists available at ScienceDirect
Journal of Fluorine Chemistry
journal homepage: www.elsevier.com/locate/fluor
Short Communication
Metal- and additive-free cascade trifluoroethylation/cyclization of organic
isoselenocyanates by phenyl(2,2,2-trifluoroethyl)iodonium triflate
⁎
Cheng-Long Zhaoa,1, Jin Shia,1, Xiuqiang Lub, Xun Wua, Cheng-Pan Zhanga,
a School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan, 430070, China
b Fuqing Branch of Fujian Normal University, Fuzhou, Fujian, 350300, China
A R T I C L E I N F O
A B S T R A C T
Keywords:
A novel and convenient cascade trifluoroethylation/cyclization of organic isoselenocyanates by phenyl(2,2,2-
trifluoroethyl)iodonium triflate is reported. A series of 2-isoselenocyanobiaryls and aryl alkyl isoselenocyanates
reacted with phenyl(2,2,2-trifluoroethyl)iodonium triflate in CH2Cl2 at 40 °C under metal- and additive-free
conditions for 3 h to provide the corresponding trifluoroethylselenolated phenanthridines and 3,4-dihy-
droisoquinoline derivatives in good to excellent yields. The reaction represents the first general approach to
access trifluoroethylselenolated phenanthridines and 3,4-dihydroisoquinolines from organic isoselenocyanates.
Trifluoroethylation
Cyclization
Isoselenocyanate
Additive-Free
Phenyl(2,2,2-trifluoroethyl)iodonium triflate
1. Introduction
have shown much powerful electrophilic trifluoroethylation reactivity
toward a variety of nucleophiles [6,7]. The Pd-catalyzed reactions of aryl
Organofluorine compounds have played a significant role in chemistry,
biology and material sciences [1]. Because of the unique features such as
small atomic radius, high electronegativity, low polarizability, strong in-
ductive effect, and good lipophilicity, the incorporation of fluorine and
fluorine-containing groups into organic molecules can dramatically
change their physical, chemical and biological properties, e.g. replacement
of a CeH or CeO bond with a CeF bond in medicinally active compounds
introduces desirable pharmacological properties like higher metabolic
stability, increased binding to target molecules, and enhanced membrane
permeability [2]. Among the commonly used fluorine-containing groups,
CF3CH2 functionality has attracted great interest in the development of
new pharmaceuticals, agrochemicals and functional materials [1–3]. A
growing number of trifluoroethyl-containing compounds with potent
biological activities have emerged in drug discovery in the past few dec-
ades [4]. Thus, developing effective and practical methods for the synth-
esis of trifluoroethylated compounds as many as possible is highly desir-
able. The direct 2,2,2-trifluoroethylation of organic scaffolds, such as
arylboronic acids or esters, aryl iodides, arenes, alkynes, and alkenes, by
using CF3CH2I, CF3CH2OTf, CF3CH2OTs, CF3CHN2, CF3CH2NH2,
CF3CHCl2, (CF3CH2SO2)2Zn, CF3CH2SO2Cl, CF3CO2H, and aryl(2,2,2-tri-
fluoroethyl)iodonium salts ([ArICH2CF3]X) as CF3CH2 transfer reagents
has been successfully accomplished under transition-metal-catalyzed or
-free conditions [5]. In these cases, aryl(2,2,2-trifluoroethyl)iodonium salts
([ArICH2CF3]X, X = OTf, NTf2), first synthesized by Umemoto in 1985,
(2,2,2-trifluoroethyl)iodonium triflates with arylboronic acids, anilides,
aromatic amides, indoles, and benzo[h]quinolines have represented the
state-of-the-art transition-metal-catalyzed trifluoroethylations using [Ar-
ICH2CF3][OTf] [6]. Notably, the catalyst-free reactions of [ArICH2CF3]X
with amines, peptides, alcohols, phenols, thiols, sulfides, carbohydrates,
thioglycosides, fatty acids, phosphines, electron-rich arenes, and iso-
thiocyanates have built a large number of useful trifluoroethylated mole-
cules [7].
Phenanthridines and isoquinolines are privileged heteroaromatic
skeletons found in natural products, pharmaceuticals, and functional
materials, showing antitumor, antiviral, antibacterial activities, and/or
optoelectronic properties [8]. A variety of 6-fluoroalkylated phenan-
thridines have been constructed by insertion of the in situ formed
fluoroalkyl radicals into the isocyano groups of 2-isocyanobiaryls,
which then undergo intramolecular cyclization to generate the final
products [9]. 2-Isothiocyanobiaryls have also been employed as
building blocks for the synthesis of phenanthridine derivatives by
functionalization of the NCS moieties [7b,10]. Nonetheless, production
of phenanthridine derivatives from 2-isoselenocyanobiaryls via reac-
tions at the isoselenocyano (NCSe) groups has not been studied [11].
Furthermore, preparation of isoquinoline derivatives by intramolecular
cyclization of aryl alkyl isothiocyanates in the presence of copper cat-
alysts or acids has been explored [12], but the analogous transforma-
tions of aryl alkyl isoselenocyanates have never been known [11].
⁎ Corresponding author.
E-mail addresses: zhangchengpan1982@hotmail.com, cpzhang@whut.edu.cn (C.-P. Zhang).
1 These two authors contributed equally.
https://doi.org/10.1016/j.jfluchem.2019.109360
Received 27 July 2019; Received in revised form 7 August 2019; Accepted 15 August 2019
Availableonline21August2019
0022-1139/©2019ElsevierB.V.Allrightsreserved.

C.-L. Zhao, et al.
JournalofFluorineChemistry226(2019)109360
Despite that aryl(2,2,2-trifluoroethyl)iodonium salts are powerful
electrophilic trifluoroethylation reagents toward a variety of nucleo-
philes, activation of isothiocyano groups by these salts without catalysts
or additives was a really challenging task because the NCS groups in 2-
isothiocyanobiaryls have much poor nucleophilicity [7b]. Since S and
Se are elements of the same main group and the latter has better nu-
cleophilicity, we wondered whether [ArICH2CF3][OTf] would initiate a
metal- and acid-free cascade 2,2,2-trifluoroethylation/cyclization of
organic isoselenocyanates.
(entry 7, Table 1). Despite the relatively low yields of 3a, most of the
starting material (1a) was converted in the above reactions (entries
1–7, Table 1). Unexpectedly, when the same reaction of 1a and 2a was
run without any additive at 40 °C for 3 h, 3a was formed in 62% yield
(entry 8, Table 1). All these results suggested that use of additives de-
pressed trifluoroethylation/cyclization, which might be attributed to
the decomposition of isoselenocyanate (1a) or both of isoselenocyanate
(1a) and (2,2,2-trifluoroethyl)iodonium triflate (2a) by the additives at
different levels. In addition, CH2Cl2 was found to be the best solvent for
the reaction among all tested solvents, including ClCH2CH2Cl, CH3CN,
toluene and 1,4-dioxane (see the supporting information (SI)).
Prolonging the reaction time from 3 h to 6 h did not significantly
change the yield of 3a (entry 9, Table 1). Increasing the molar
equivalents of 2a from 2.0 equiv to 3.0 equiv could slightly improve the
yield of 3a (67%, entry 10, Table 1). When 2a was replaced by mesityl
Moreover, 2,2,2-trifluoroethyl selenoethers have been rarely ex-
plored, probably owing to the lack of relevant selenium substances or
reagents [13]. Construction of 2,2,2-trifluoroethyl selenoethers is of
significant importance in view of the biological potentials of organo-
selenium molecules. Previous methods for the synthesis of 2,2,2-tri-
fluoroethyl aryl selenides included the elimination-addition of 2-chloro-
2,2-difluoroethyl phenyl selenide with KF in the presence of a catalytic
amount of 18-crown-6, the trifluoroethylation of aryl selenolate anions
with 2,2,2-trifluoroethyl tosylate, which was generated in situ from
reduction of diaryl diselenide by sodium, and the one-pot reaction of
aryl halides with elemental selenium, 1,1,1-trifluoro-2-iodoethane and
NaBH4 using CuI/phen as a catalyst (Scheme 1) [13]. In this article, we
found that reactions of 2-isoselenocyanobiaryls and aryl alkyl iso-
selenocyanates with phenyl(2,2,2-trifluoroethyl)iodonium triflate
without any catalyst or additive provided trifluoroethylselenolated
phenanthridines and 3,4-dihydroisoquinoline derivatives in good to
excellent yields.
(2,2,2-trifluoroethyl)iodonium triflate [MesICH2CF3][OTf] (2b),
a
comparable yield of 3a (65%) was obtained, implying that 2b was also
an effective reagent in this reaction (entry 11, Table 1).
With the optimized reaction conditions (entry 10, Table 1) in hand,
the substrate scope of the metal- and additive-free trifluoroethylation/
cyclization reaction was examined (Table 2). To our delight, the stan-
dard conditions enabled smooth cascade trifluoroethylation/cyclization
of various electron-rich 2-isoselenocyanobiaryls. The electron-donating
R1 groups (e.g., methyl (1b), methoxy (1c), tert-butyl (1d), benzyloxy
(1e)) on the aryl rings of 2-isoselenocyanobiaryls benefited the reac-
tion, affording 3b-e in higher yields (58–68%) than that of 3a. When 2-
isoselenocyanato-4′-phenoxy-1,1′-biphenyl (1f) reacted with 2a at 40 °C
for 3 h, the expected 8-phenoxy-6-((2,2,2-trifluoroethyl)selanyl)phe-
nanthridine (3f) was obtained in 39% yield. The lower yield of 3f might
be caused by the presence of a weak electron-withdrawing phenyl
group in 1f. Moreover, the similar reactions of 2-isoselenocyanobiaryls
bearing electron-withdrawing R1 groups such as chloro (1g) and cyano
(1h) groups gave no desired products, even though the starting mate-
rials were completely consumed. All these results suggested that the
electronic nature of R1 group had a very big influence on the reaction.
Furthermore, reactions of 2-isoselenocyanato-3′,5′-dimethyl-1,1′-bi-
phenyl (1i), 2-isoselenocyanato-3′,5′-dimethoxy-1,1′-biphenyl (1j), and
2-isoselenocyanato-4′-methoxy-3′-methyl-1,1′-biphenyl (1k) with 2a
under the standard conditions furnished 3i in 89% yield, 3j in 95%
yield, and 3k in 71% yield. It seemed that the more electron-donating
R1 groups attached on the aryl rings of 2-isoselenocyanobiaryls pro-
vided the higher yields of the desired products. The position of sub-
stituents on the aryl rings of 2-isoselenocyanobiaryls also considerably
2. Results and discussion
At the beginning, by following our previous procedure for the
synthesis of trifluoroethylthiol phenanthridines from 2-iso-
thiocyanobiaryls [7b], the reaction of 2-isoselenocyanato-1,1′-biphenyl
(1a) with phenyl(2,2,2-trifluoroethyl)iodonium triflate (2a) was car-
ried out in CH2Cl2 in the presence of TfOH (3 equiv) at 40 °C for 6 h,
which, however, afforded 6-((2,2,2-trifluoroethyl)selanyl)phenan-
thridine (3a) in a low yield (36%) (entry 1, Table 1). The result in-
dicated that the optimal reaction conditions for trifluoroethylation/
cyclization of 2-isothiocyanobiaryls with 2a were not very applicable
for that of 2-isoselenocyanobiaryls. Addition of bases such as KF,
K3PO4, CH3COOK, Et3N and Cs2CO3 to the reaction mixture of 1a and
2a under the similar conditions led to 3a in 37–59% yields (entries 2–6,
Table 1). When the reaction of 1a and 2a was conducted with 4 Å
molecular sieves in CH2Cl2 at 40 °C for 3 h, only 2% of 3a was formed
Scheme 1. The known methods for the synthesis of 2,2,2-trifluoroethyl aryl selenides.
2

C.-L. Zhao, et al.
JournalofFluorineChemistry226(2019)109360
Table 1
Screening of the optimal reaction conditions for trifluoroethylation/cyclization of 1a by 2a.
Entrya
Additive
Conversion (1a, %)b
Yield (3a, %)b
1c,d
2
TfOH (3.0 equiv)
KF (1.0 equiv)
K3PO4 (1.0 equiv)
CH3COOK (1.0 equiv)
Et3N (1.0 equiv)
Cs2CO3 (1.0 equiv)
4Å MS (50 mg)
none
> 99
97
36
59
3
87
37
4
> 99
68
49
5
38
6
98
43
7
87
2
8
> 99
> 99
> 99
> 99
62
9d
10e
11e,g
none
63
none
67 (51f)
65
none
a
b
Reaction conditions: 1a (0.1 mmol), 2a (0.2 mmol), additive (x equiv), CH2Cl2 (2 mL), N2, 40 °C, 3 h.
The conversion of 1a and the yields of 3a were determined by HPLC (λ = 244 nm, water/methanol = 10 : 90 (v / v)) using pure 2-isoselenocyanato-1,1′-
biphenyl (1a, tR = 7.698 min) and 6-((2,2,2-trifluoroethyl)selanyl)phenanthridine (3a, tR = 10.157 min) as external standards, respectively.
c
d
e
f
Under ambient atmosphere.
6 h.
1a (0.2 mmol) and 2a (0.6 mmol).
Isolated yield.
g
[PhICH2CF3][OTf] (2a) was replaced by [MesICH2CF3][OTf] (2b).
affected the conversion. Reactions of 2-isoselenocyanato-4′-methyl-
1,1′-biphenyl (1b) and 2-isoselenocyanato-2′-methyl-1,1′-biphenyl
(1m) with 2a at 40 °C for 3 h formed 3b (68%) and 3m (56%) as the
single products, while the same reaction of 2-isoselenocyanato-3′-me-
thyl-1,1′-biphenyl (1l) with 2a afforded a mixture of 7-methyl-6-
((2,2,2-trifluoroethyl)selanyl)phenanthridine (3l) and 9-methyl-6-
((2,2,2-trifluoroethyl)selanyl)phenanthridine (3 l’) in 77% total yield.
The molar ratio of 3l / 3l’ = 1 : 6.7 was determined by NMR analysis of
the isolated product. In a similar manner, treatment of 1-(2-iso-
selenocyanatophenyl)naphthalene (1n) with 2a furnished 3n in 57%
yield. Heteroaromatic systems were also suitable substrates for the re-
action. 5-(2-Isoselenocyanatophenyl)benzo[d][1,3]dioxole (1o), 2-(2-
isoselenocyanatophenyl)thiophene (1p), 3-(2-isoselenocyanatophenyl)
thiophene (1q), 1-(2-isoselenocyanatophenyl)thianthrene (1r), and 4-
(2-isoselenocyanatophenyl)dibenzo[b,d]furan (1s) reacted with 2a
under the standard conditions to give the corresponding trifluoroethyl
cyclization products (3o-s) in up to 97% yield. The frustrated formation
of 6-((2,2,2-trifluoroethyl)selanyl)benzo[5,6][1,4]dithiino[2,3-k]phe-
nanthridine (3r) from 1r was likely ascribed to the competitive reaction
of 2a at the sulfur centers of 1r because these cites also have con-
siderable nucleophilicity towards 2a [14]. Again, the electronic prop-
erties of R2 groups on the aryl rings of 2-isoselenocyanobiaryls have an
impact on the reaction. Treatment of 2-isoselenocyanato-4-methyl-1,1′-
biphenyl (1t) and 5-chloro-2-isoselenocyanato-1,1′-biphenyl (1u) with
2a at 40 °C for 3 h afforded 3t in 52% yield (vs 68% of 3b) and 3 u in
44% yield (vs 0% of 3g), respectively. The substituent effects of R2
groups appeared to be smaller than that of R1 groups for the tri-
fluoroethylation/cyclization reaction as the substrate (1u) containing a
weak electron-withdrawing R2 = Cl group on the aryl ring could give a
moderate yield (3u). However, this reaction was not amenable for 2-
isoselenocyanobiaryl bearing a strong electron-withdrawing R2 group
like NO2 (1v) on the aryl ring, which afforded no desired product (3v).
In addition, the metal- and additive-free cascade trifluoroethylation/
cyclization reaction was applicable to electron-rich aryl alkyl iso-
selenocyanates (Table 2). Reaction of 1-(2-isoselenocyanatoethyl)-4-me-
thylbenzene (1w) with 2a under the standard conditions provided 3w in
21% yield. Analogously, treatment of 4-(2-isoselenocyanatoethyl)-1,2-
dimethylbenzene (1x), 4-(2-isoselenocyanatoethyl)-1,2-dimethoxybenzene
(1y), and 5-(2-isoselenocyanatoethyl)benzo[d][1,3]dioxole (1z) with 2a
formed 3x-z in 46–78% yields. The reactions occurred at both the electron-
rich and least sterically hindered aromatic carbon sites to produce the tri-
fluoroethylselenolated 3,4-dihydroisoquinolines with specific regioselec-
tivity. When (2-isoselenocyanatoethyl)benzene (1aa) was mixed with 2a in
the same reaction, only trace amounts of the trifluoroethylselenolated
product was formed, which was determined by both TLC and 19F NMR
analyses of the reaction mixture. These observations implied that the strong
electron-donating groups on the aromatic rings of aryl alkyl iso-
selenocyanates favorably improved the reaction and that the transformation
was very sensitive to the inherent electronic nature of the substituents. It
should be noted that all trifluoroethylselenol 3,4-dihydroisoquinoline deri-
vatives in Table 2 were unstable and tended to decompose when they were
chromatographed on silica gel. To obtain good yields of the products, their
separation should be performed by column chromatography on aluminum
oxide as fast as possible.
On the basis of the above results and previous report [7b], a plau-
sible reaction mechanism for the metal- and additive-free cascade tri-
fluoroethylation/cyclization was suggested (Scheme 2). First, phenyl
(2,2,2-trifluoroethyl)iodonium triflate (2a) is attacked at the iodonium
center by the nucleophilic lone-pair electrons of selenium in iso-
selenocyanates (1) to form a cation intermediate (4 or 5) (path a).
Then, intermediate 4 or 5 undergoes intramolecular Friedel-Crafts-type
cyclization to afford 6. Reductive elimination of trifluoroethyl group
and selenium moiety from 6 at the iodine center followed by deproto-
nation provides the final product (3). Besides, the straightforward nu-
cleophilic attack of 2a at the α-carbon site of CH2CF3 group by the lone-
pair electrons of Se atom of isoselenocyanates (1) is also possible, which
produces complex 7 or 8 as a key cation intermediate (path b). Sub-
sequently, intramolecular Friedel-Crafts-type cyclization of 7 or 8
generates 9, which is deprotonated under the reaction conditions to
eventually supply the desired product (3).
3. Conclusion
In summary, we have developed a convenient and efficient method for
3

C.-L. Zhao, et al.
JournalofFluorineChemistry226(2019)109360
Table 2
Transition-metal- and additive-free cascade trifluoroethylation/cyclization of 2-isoselenocyanobiaryls (1)
by [PhICH2CF3][OTf] (2a).a
aReaction conditions: 1 (0.2 mmol), 2a (0.6 mmol), CH2Cl2 (2 mL), 40 °C, N2, 3 h. Isolated yields.
the one-pot synthesis of trifluoroethylselenolated phenanthridines and 3,4-
dihydroisoquinolines under metal- and additive-free conditions. The cas-
cade trifluoroethylation/cyclization of 2-isoselenocyanobiaryls and aryl
alkyl isoselenocyanates (1) by phenyl(2,2,2-trifluoroethyl)iodonium triflate
(2a) in CH2Cl2 at 40 °C for 3 h afforded a variety of trifluoroethylselenol
phenanthridines and 3,4-dihydroisoquinoline derivatives (3) in good to
excellent yields. The electronic nature of substituents on the aryl rings of 1
greatly affected the reaction. The electron-donating substituents could sig-
nificantly promote the yields of the products under standard conditions.
This protocol is the first report to access trifluoroethylselenolated phenan-
thridine and isoquinoline derivatives from isoselenocyanates without using
any transition metal or additive. Further application of aryl(2,2,2-tri-
fluoroethyl)iodonium salts as promising trifluoroethylation reagents in new
fluoroalkylation reactions is currently underway in our laboratory.
or external standard. The coupling constants were reported in Hertz
(Hz). The following abbreviations were used to explain the multi-
plicities: s = singlet, d = doublet, t = triplet, q = quartet, m = multi-
plet, brs = broad singlet. The HPLC experiments were carried out on a
Wufeng LC-100 II instrument (column: Shodex, C18, 5 μm,
4.6 × 250 mm), and the HPLC yields of the product were determined by
using the corresponding pure compound as the external standard.
Melting points were measured and uncorrected. MS experiments were
performed on a TOF-Q ESI or EI instrument. Trifluoroethylation re-
agents 2a and 2b were synthesized according to the literature [15].
Substrates 1a-v and 1 w-1z were synthesized according to the litera-
tures [16–18]. Solvents were dried before use according to the litera-
ture [19]. Other reagents in the reactions were all purchased from the
commercial sources and used without further purification.
4. Experimental section
4.2. General procedures for the reaction of isosocyanates with [ArICH2CF3]
[OTf]
4.1. General considerations
Procedure A: Under a nitrogen atmosphere, a sealed tube was
charged with isosocyanate (1a-1v, 0.2 mmol), [PhICH2CF3][OTf]
(261.6 mg, 0.6 mmol) and CH2Cl2 (2 mL) with stirring. The mixture was
reacted at 40 °C for 3 h, cooled to room temperature, quenched with
saturated aqueous NaHCO3 solution, and extracted with CH2Cl2
(3 × 25 mL). The combined organic layers were dried over anhydrous
All reactions were carried out under a nitrogen atmosphere unless
otherwise specified. The NMR spectra were recorded in CDCl3 on a
500 MHz (for 1H), 471 (for 19F), and 126 or 100 MHz (for 13C) spec-
trometer. All chemical shifts were reported in ppm relative to TMS
(0 ppm for 1H NMR) and PhCF3 (63.5 ppm for 19F NMR) as an internal
4

C.-L. Zhao, et al.
JournalofFluorineChemistry226(2019)109360
Scheme 2. A proposed reaction mechanism for the metal- and additive-free cascade trifluoroethylation/cyclization of isoselenocyanates.
Na2SO4 and concentrated to dryness under reduced pressure. The re-
sidue was purified by column chromatography on silica gel using a
mixture of petroleum ether and ethyl acetate as eluents to give the
trifluoroethylselenolated product (3a-3v).
ethyl acetate (40:1 (v/v)) as eluents for column chromatography. M.p.:
136–138 °C. 1H NMR (500 MHz, CDCl3) δ 8.43-8.40 (m, 2 H), 8.04 (d, J
=8.1 Hz, 1 H), 7.83 (s, 1 H), 7.67 (tm, J =7.5 Hz, 1 H), 7.63 (d, J
=8.4 Hz, 1 H), 7.59 (tm, J =7.6 Hz, 1 H), 4.32 (q, J =10.8 Hz, 2 H),
2.58 (s, 3 H). 19F NMR (471 MHz, CDCl3) δ -63.6 (t, J =10.6 Hz, 3 F).
13C NMR (126 MHz, CDCl3) δ 153.4, 143.8, 138.0, 132.9, 130.1, 128.9,
128.5, 126.7, 126.5, 126.2 (q, J =273.8 Hz), 125.5, 123.4, 122.4,
122.1, 25.3 (q, J =33.2 Hz), 21.7. IR (KBr): 3073, 3006, 2940, 1623,
1611, 1567, 1532, 1480, 1461, 1409, 1383, 1367, 1345, 1294, 1266,
1238, 1212, 1175, 1158, 1114, 1061, 969, 949, 878, 859, 835, 817,
779, 755, 722, 709, 686, 632 cm−1. HRMS-ESI (m/z) calcd. for
Procedure B: Under a nitrogen atmosphere, a sealed tube was
charged with isosocyanate (1w-1z, 0.2 mmol), [PhICH2CF3][OTf]
(261.6 mg, 0.6 mmol) and CH2Cl2 (2 mL) with stirring. The mixture was
reacted at 40 °C for 3 h, cooled to room temperature, quenched with
saturated aqueous NaHCO3 solution, and extracted with CH2Cl2
(3 × 25 mL). The combined organic layers were dried over anhydrous
Na2SO4 and concentrated to dryness under reduced pressure. The re-
sidue was purified by flash column chromatography (within 5 min) on
aluminum oxide (basic) using a mixture of petroleum ether and ethyl
acetate as eluents to give the trifluoroethylselenolated product (3w-3z).
C
16H13F3NSe ([M+H]+): 356.0160; found: 356.0154.
4.2.3. 8-Methoxy-6-((2,2,2-trifluoroethyl)selanyl)phenanthridine (3c)
Light yellow solid, 41.4 mg, 64% yield, a mixture of petroleum ether
and ethyl acetate (40:1 (v/v)) as eluents for column chromatography.
M.p.: 116–117 °C. 1H NMR (500 MHz, CDCl3) δ 8.46 (d, J =9.0 Hz,
1 H), 8.39 (d, J =8.0 Hz, 1 H), 8.04 (d, J =8.0 Hz, 1 H), 7.65 (t, J
=7.2 Hz, 1 H), 7.59 (t, J =7.6 Hz, 1 H), 7.45 (d, J =9.0 Hz, 1 H), 7.36
(s, 1 H), 4.32 (q, J =10.7 Hz, 2 H), 3.99 (s, 3 H). 19F NMR (471 MHz,
CDCl3) δ -63.7 (t, J =10.8 Hz, 3 F). 13C NMR (126 MHz, CDCl3) δ 159.1,
4.2.1. 6-((2,2,2-Trifluoroethyl)selanyl)phenanthridine (3a)
White solid, 29.7 mg, 51% yield, a mixture of petroleum ether and
ethyl acetate (50:1 (v/v)) as eluents for column chromatography. M.p.:
101–103 °C. 1H NMR (500 MHz, CDCl3) δ 8.58 (d, J =8.3 Hz, 1 H), 8.49
(d, J =8.1 Hz, 1 H), 8.10 (d, J =8.2 Hz, 1 H), 8.07 (d, J =8.1 Hz, 1 H),
7.86 (t, J =7.5 Hz, 1 H), 7.73-7.68 (m, 2 H), 7.62 (t, J =7.8 Hz, 1 H),
4.32 (q, J =10.8 Hz, 2 H). 19F NMR (471 MHz, CDCl3) δ -63.7 (t, J
=10.8 Hz, 3 F). 13C NMR (126 MHz, CDCl3) δ 153.9, 144.1, 132.4,
131.2, 129.0, 129.0, 127.8, 126.6, 126.6, 126.2 (q, J =274.3 Hz),
126.1, 123.3, 122.6, 122.3, 25.4 (q, J =33.4 Hz). IR (KBr): 3076, 3010,
2942, 2852, 1610, 1566, 1523, 1483, 1456, 1410, 1341, 1291, 1275,
1239, 1227, 1194, 1156, 1133, 1120, 1051, 946, 862, 843, 831, 755,
718, 632, 619 cm−1. HRMS-ESI (m/z) calcd. for C15H11F3N74Se ([M
+H]+): 336.0063; found: 336.0060.
152.7, 143.2, 128.9, 128.0, 127.9, 126.6, 126.5, 126.2 (q,
J
=274.7 Hz), 124.3, 123.5, 121.8, 121.8, 106.1, 55.6, 25.6 (q, J
=33.4 Hz). IR (KBr): 3060, 3020, 2999, 2968, 2935, 2848, 1674, 1620,
1568, 1529, 1484, 1462, 1446, 1421, 1403, 1361, 1294, 1275, 1243,
1216, 1189, 1173, 1151, 1115, 1063, 1040, 975, 946, 938, 886, 827,
759, 752, 726, 716, 655, 632 cm−1. HRMS-ESI (m/z) calcd. for
C
16H13F3NOSe ([M+H]+): 372.0109; found: 372.0114.
4.2.4. 8-(Tert-butyl)-6-((2,2,2-trifluoroethyl)selanyl)phenanthridine (3d)
Gray solid, 51.2 mg, 65% yield, a mixture of petroleum ether and
ethyl acetate (40:1 (v/v)) as eluents for column chromatography. M.p.:
4.2.2. 8-Methyl-6-((2,2,2-trifluoroethyl)selanyl)phenanthridine (3b)
White solid, 48.4 mg, 68% yield, a mixture of petroleum ether and
5

C.-L. Zhao, et al.
JournalofFluorineChemistry226(2019)109360
111–113 °C. 1H NMR (500 MHz, CDCl3) δ 8.51 (d, J =8.7 Hz, 1 H), 8.47
(d, J =8.1 Hz, 1 H), 8.06 (dd, J = 8.2, 0.9 Hz, 1 H), 8.04 (d, J =1.8 Hz,
1 H), 7.94 (dd, J = 8.7, 1.9 Hz, 1 H), 7.68 (tm, J =7.6 Hz, 1 H), 7.61
(tm, J =7.6 Hz,), 4.34 (q, J =10.8 Hz, 2 H), 1.49 (s, 9 H). 19F NMR
(471 MHz, CDCl3) δ -63.6 (t, J =10.9 Hz, 3 F). 13C NMR (126 MHz,
CDCl3) δ 153.9, 151.2, 143.9, 130.2, 129.7, 128.9, 128.6, 126.6, 126.5,
126.2 (q, J =274.1 Hz), 123.4, 122.5, 122.2, 121.6, 35.2, 31.3, 25.3 (q,
J =33.3 Hz). IR (KBr): 3063, 2999, 2961,2903, 2868, 1609, 1576,
1557, 1533, 1481, 1462, 1405, 1365, 1349, 1290, 1262, 1217, 1185,
1160, 1114, 1059, 967, 875, 867, 834, 783, 763, 724, 706, 670, 657,
182–184 °C. 1H NMR (500 MHz, CDCl3) δ 8.25 (d, J =8.1 Hz, 1 H), 7.93
(d, J =8.0 Hz, 1 H), 7.64 (t, J =7.5 Hz, 1 H), 7.50 (t, J =7.7 Hz, 1 H),
7.36 (s, 1 H), 6.55 (s, 1 H), 4.18 (q, J =11.3 Hz, 2 H), 4.00 (s, 3 H), 3.95
(s, 3 H). 19F NMR (471 MHz, CDCl3) δ -62.5 (t, J =11.4 Hz, 3 F). 13C
NMR (126 MHz, CDCl3) δ 162.0, 158.5, 150.8, 144.1, 136.4, 129.1,
128.7, 127.0 (q, J =274.2 Hz), 125.7, 122.5, 122.2, 113.3, 98.7, 95.6,
55.5, 55.4, 25.1 (q, J =31.5 Hz). IR (KBr): 3105, 3093, 3012, 2993,
2937, 2856, 2835, 1617, 1582, 1565, 1516, 1488, 1459, 1440, 1412,
1363, 1341, 1271, 1212, 1166, 1136, 1113, 1054, 1034, 1025, 945,
884, 862, 833, 820, 780, 760, 722, 654, 632 cm−1. HRMS-ESI (m/z)
calcd. for C17H15F3NO2Se ([M+H]+): 402.0215; found: 402.0216.
631 cm−1
.
HRMS-ESI (m/z) calcd. for C19H19F3NSe ([M+H]+):
398.0629; found: 398.0624.
4.2.9. 8-Methoxy-9-methyl-6-((2,2,2-trifluoroethyl)selanyl)
4.2.5. 8-(Benzyloxy)-6-((2,2,2-trifluoroethyl)selanyl)phenanthridine (3e)
White solid, 52.0 mg, 58% yield, a mixture of petroleum ether and
ethyl acetate (40:1 (v/v)) as eluents for column chromatography. M.p.:
143–145 °C. 1H NMR (500 MHz, CDCl3) δ 8.52 (d, J =9.0 Hz, 1 H), 8.43
(d, J =8.0 Hz, 1 H), 8.05 (d, J =8.1 Hz, 1 H), 7.66 (tm, J =7.5 Hz, 1 H),
7.61 (tm, J =7.50 Hz, 1 H), 7.57-7.50 (m, 4 H), 7.45 (t, J =7.5 Hz, 2 H),
7.38 (t, J =7.4 Hz, 1 H), 5.26 (s, 2 H), 4.31 (q, J =10.8 Hz, 2 H). 19F
phenanthridine (3k)
White solid, 54.2 mg, 71% yield, a mixture of petroleum ether and
ethyl acetate (40:1 (v/v)) as eluents for column chromatography. M.p.:
144–146 °C. 1H NMR (500 MHz, CDCl3) δ 8.42 (d, J =8.0 Hz, 1 H), 8.30
(s, 1 H), 8.04 (d, J =8.1 Hz, 1 H), 7.65 (tm, J =7.5 Hz, 1 H), 7.59 (tm, J
=7.5 Hz, 1 H), 7.25 (s, 1 H), 4.34 (q, J =10.8 Hz, 2 H), 4.03 (s, 3 H),
2.49 (s, 3 H). 19F NMR (471 MHz, CDCl3) δ -63.6 (t, J =10.7 Hz, 3 F).
13C NMR (126 MHz, CDCl3) δ 157.9, 152.3, 143.4, 133.3, 128.8, 127.7,
126.4, 126.3, 126.3, 126.2 (q, J =274.5 Hz), 124.1, 123.3, 121.8,
103.8, 55.6, 25.5 (q, J =33.4 Hz), 17.3. IR (KBr): 3066, 2999, 2962,
2938, 2835, 1623, 1569, 1517, 1494, 1464, 1447, 1406, 1365, 1296,
1266, 1243, 1211, 1191, 1153, 1115, 1061, 1045, 978, 946, 919, 874,
NMR (471 MHz, CDCl3)
δ
-63.7 (t,
J
=10.8 Hz, 3 F). 13C NMR
(126 MHz, CDCl3) δ 158.2, 152.8, 143.4, 136.2, 128.9, 128.8, 128.4,
128.0, 127.9, 127.8, 126.7, 126.6, 126.1 (q, J =274.8 Hz), 124.4,
123.5, 122.2, 121.8, 107.8, 70.6, 25.6 (q, J =33.3 Hz). IR (KBr): 3068,
3040, 3012, 2945, 2909, 2872, 1615, 1568, 1531, 1486, 1462, 1414,
1387, 1359, 1299, 1275, 1245, 1222, 1208, 1179, 1128, 1055, 1034,
1017, 995, 947, 918, 899, 864, 836, 824, 755, 717, 707, 693, 634, 621
cm−1. HRMS-ESI (m/z) calcd. for C22H17F3NOSe ([M+H]+): 448.0422;
found: 448.0429.
827, 790, 753, 716, 631 cm−1
. HRMS-ESI (m/z) calcd. for
C
17H15F3NOSe ([M+H]+): 386.0265; found: 386.0270.
4.2.10. 7-Methyl-6-((2,2,2-trifluoroethyl)selanyl)phenanthridine (3l)
White solid, petroleum ether as eluent for preparative TLC plate.
M.p.: 99–101 °C. 1H NMR (500 MHz, CDCl3) δ 8.52 (d, J =8.3 Hz, 1 H),
8.48 (d, J =8.3 Hz, 1 H), 7.99 (d, J =8.1 Hz, 1 H), 7.70-7.66 (m, 2 H),
7.59 (t, J =7.8 Hz, 1 H), 7.49 (d, J =7.2 Hz, 1 H), 4.29 (q, J =11.0 Hz,
2 H), 3.14 (s, 3 H). 19F NMR (471 MHz, CDCl3) δ -63.1 (t, J =11.0 Hz,
3 F). 13C NMR (126 MHz, CDCl3) δ 153.0, 142.9, 136.5, 134.4, 131.7,
130.3, 128.9, 128.5, 127.3, 126.5, 126.3 (q, J =274.3 Hz), 123.3,
122.5, 121.1, 27.4 (q, J =32.2 Hz), 24.6. IR (KBr): 3059, 3015, 2958,
2917, 2849, 1601, 1581, 1567, 1520, 1475, 1458, 1446, 1396, 1376,
1286, 1265, 1218, 1186, 1112, 1050, 1034, 936, 832, 804, 755, 730,
4.2.6. 8-Phenoxy-6-((2,2,2-trifluoroethyl)selanyl)phenanthridine (3f)
Gray solid, 34.1 mg, 39% yield, a mixture of petroleum ether and
ethyl acetate (40:1 (v/v)) as eluents for column chromatography. M.p.:
112–114 °C. 1H NMR (500 MHz, CDCl3) δ 8.55 (d, J =9.0 Hz, 1 H), 8.43
(d, J =8.0 Hz, 1 H), 8.06 (dd, J = 8.1, 0.9 Hz, 1 H), 7.68 (tm, J
=7.6 Hz, 1 H), 7.63-7.60 (m, 2 H), 7.56 (dd, J = 9.0, 2.4 Hz, 1 H), 7.44
(tm, J =8.0 Hz, 2 H), 7.23 (t, J =7.5 Hz, 1 H), 7.14 (d, J =7.7 Hz, 2 H),
4.27 (q, J =10.8 Hz, 2 H). 19F NMR (471 MHz, CDCl3) δ -63.7 (t, J
=10.8 Hz, 3 F). 13C NMR (126 MHz, CDCl3) δ 157.0, 156.3, 153.0,
143.6, 130.2, 129.0, 128.5, 128.0, 127.9, 126.8, 126.1 (q,
J
704, 633 cm−1
.
HRMS-ESI (m/z) calcd. for C16H12F3NNaSe
=274.5 Hz), 124.7, 124.4, 123.4, 123.2, 122.0, 119.5, 113.2, 25.5 (q, J
=33.5 Hz). IR (KBr): 3064, 3011, 2938, 1617, 1598, 1587, 1567, 1529,
1480, 1459, 1409, 1352, 1298, 1243, 1220, 1170, 1155, 1115, 1074,
1056, 1023, 989, 907, 856, 830, 812, 758, 720, 711, 701, 688, 656, 634
cm−1. HRMS-ESI (m/z) calcd. for C21H15F3NOSe ([M+H]+): 434.0265;
found: 434.0256.
([M + Na]+): 377.9979; found: 377.9981.
4.2.11. 9-Methyl-6-((2,2,2-trifluoroethyl)selanyl)phenanthridine (3l’)
White solid, petroleum ether as eluent for preparative TLC plate.
M.p.: 102–104 °C. 1H NMR (500 MHz, CDCl3) δ 8.47 (d, J =8.1 Hz,
1 H), 8.34 (s, 1 H), 8.04 (d, J =8.1 Hz, 1 H), 7.97 (d, J =8.3 Hz, 1 H),
7.69 (t, J =7.6 Hz, 1 H), 7.60 (t, J =7.6 Hz, 1 H), 7.49 (d, J =8.3 Hz,
1 H), 4.30 (q, J =10.8 Hz, 2 H), 2.63 (s, 3 H). 19F NMR (471 MHz,
CDCl3) δ -63.7 (t, J =10.8 Hz, 3 F). 13C NMR (100 MHz, CDCl3) δ 153.6,
4.2.7. 7,9-Dimethyl-6-((2,2,2-trifluoroethyl)selanyl)phenanthridine (3i)
White solid, 65.9 mg, 89% yield, a mixture of petroleum ether and
ethyl acetate (40:1 (v/v)) as eluents for column chromatography. M.p.:
113–115 °C. 1H NMR (500 MHz, CDCl3) δ 8.39 (d, J =8.1 Hz, 1 H), 8.18
(s, 1 H), 7.95 (dd, J = 8.1, 0.8 Hz, 1 H), 7.64 (tm, J =7.5 Hz, 1 H), 7.54
(tm, J =7.7 Hz, 1 H), 7.22 (s, 1 H), 4.29 (q, J =11.0 Hz, 2 H), 3.03 (s,
3 H), 2.51 (s, 3 H). 19F NMR (471 MHz, CDCl3) δ -62.9 (t, J =11.0 Hz,
3 F). 13C NMR (126 MHz, CDCl3) δ 152.7, 143.0, 140.4, 136.1, 134.5,
133.3, 128.7, 128.4, 126.4 (q, J =274.4 Hz), 126.2, 125.2, 123.2,
122.4, 120.7, 27.3 (q, J =32.3 Hz), 24.4, 21.7. IR (KBr): 3068, 3008,
2967, 2945, 1615, 1564, 1507, 1482, 1460, 1450, 1398, 1373, 1349,
1331, 1286, 1272, 1255, 1207, 1173, 1111, 1095, 1056, 1030, 973,
144.3, 141.9, 132.5, 129.5, 129.0, 128.9, 126.4, 126.3 (q,
J
=274.4 Hz), 126.0, 124.8, 123.3, 122.3, 122.3, 25.3 (q, J =33.2 Hz),
22.3. IR (KBr): 3060, 3040, 2991, 2927, 2849, 1621, 1571, 1518, 1495,
1461, 1417, 1374, 1348, 1338, 1287, 1270, 1213, 1155, 1108, 1058,
946, 873, 845, 831, 801, 753, 722, 717, 708, 691, 633, 622, 616 cm−1
.
HRMS-ESI (m/z) calcd. for C16H13F3NSe ([M+H]+): 356.0160; found:
356.0155.
4.2.12. 10-Methyl-6-((2,2,2-trifluoroethyl)selanyl)phenanthridine (3m)
White solid, 39.9 mg, 56% yield, a mixture of petroleum ether and
ethyl acetate (40:1 (v/v)) as eluents for column chromatography. M.p.:
125–127 °C. 1H NMR (500 MHz, CDCl3) δ 8.74 (d, J =8.4 Hz, 1 H), 8.11
(dd, J = 8.1, 1.3 Hz, 1 H), 8.02 (d, J =8.0 Hz, 1 H), 7.72-7.68 (m, 2 H),
7.62-7.57 (m, 2 H), 4.31 (q, J =10.8 Hz, 2 H), 3.09 (s, 3 H). 19F NMR
(471 MHz, CDCl3) δ -63.6 (t, J =10.8 Hz, 3 F). 13C NMR (126 MHz,
CDCl3) δ 154.6, 144.9, 135.9, 135.4, 131.8, 129.3, 128.2, 127.9, 127.1,
126.7, 126.3 (q, J =274.4 Hz), 125.8, 124.8, 124.7, 26.7, 25.8 (q, J
941, 931, 887, 859, 852, 834, 787, 757, 730, 706, 632, 621 cm−1
.
HRMS-ESI (m/z) calcd. for C17H15F3NSe ([M+H]+): 370.0316; found:
370.0308.
4.2.8. 7,9-Dimethoxy-6-((2,2,2-trifluoroethyl)selanyl)phenanthridine (3 j)
White solid, 76.3 mg, 95% yield, a mixture of petroleum ether and
ethyl acetate (40:1 (v/v)) as eluents for column chromatography. M.p.:
6

C.-L. Zhao, et al.
JournalofFluorineChemistry226(2019)109360
=33.2 Hz). IR (KBr): 3064, 3018, 2969, 2949, 2880, 1573, 1526, 1477,
1457, 1442, 1404, 1381, 1344, 1290, 1262, 1213, 1178, 1131, 1108,
1062, 997, 866, 822, 804, 761, 719, 631 cm−1. HRMS-ESI (m/z) calcd.
for C16H13F3NSe ([M+H]+): 356.0160; found: 356.0162.
4.2.17. 6-((2,2,2-Trifluoroethyl)selanyl)benzo[5,6][1,4]dithiino[2,3-k]
phenanthridine (3r)
White solid, 25.9 mg, 27% yield, a mixture of petroleum ether and
ethyl acetate (60:1 (v/v)) as eluents for column chromatography. M.p.:
182–184 °C. 1H NMR (500 MHz, CDCl3) δ 9.54 (d, J =8.2 Hz, 1 H), 8.09
(dd, J = 8.0, 0.8 Hz, 1 H), 8.00 (d, J =8.4 Hz, 1 H), 7.87 (d, J =8.4 Hz,
1 H), 7.78 (t, J =7.5 Hz, 1 H), 7.72 (tm, J =7.7 Hz, 1 H), 7.63 (d, J
=7.3 Hz, 1 H), 7.58 (d, J =7.5 Hz, 1 H), 7.34 (td, J = 7.4, 0.8 Hz, 1 H),
7.28 (td, J = 7.7, 0.8 Hz, 1 H), 4.27 (q, J =10.7 Hz, 2 H). 19F NMR
(471 MHz, CDCl3) δ -63.7 (t, J =10.8 Hz, 3 F). 13C NMR (126 MHz,
CDCl3) δ 153.9, 145.2, 140.7, 135.9, 135.7, 134.9, 132.3, 129.4, 128.9,
128.8, 128.7, 128.5, 128.3, 128.1, 127.1, 126.1 (q, J =274.2 Hz),
125.8, 125.2, 122.8, 26.1 (q, J = 33.7). IR (KBr): 3050, 3016, 2958,
2937, 2848, 1574, 1467, 1449, 1418, 1367, 1328, 1302, 1290, 1278,
1267, 1241, 1212, 1151, 1120, 1109, 1049, 983, 811, 754, 744, 729,
707, 669, 636 cm−1. HRMS-ESI (m/z) calcd. for C21H13F3NS2Se ([M
+H]+): 479.9601; found: 479.9603.
4.2.13. 6-((2,2,2-Trifluoroethyl)selanyl)benzo[k]phenanthridine (3n)
Yellow oil, 44.4 mg, 57% yield, a mixture of petroleum ether and
ethyl acetate (50:1 (v/v)) as eluents for column chromatography. 1H
NMR (500 MHz, CDCl3) δ 8.03 (d, J =7.3 Hz, 1 H), 7.86 (d, J =8.1 Hz,
1 H), 7.79 (d, J =7.4 Hz, 1 H), 7.75 (d, J =8.0 Hz, 1 H), 7.58 (t, J
=7.6 Hz, 1 H), 7.47 (t, J =7.6 Hz, 1 H), 7.43-7.37 (m, 2 H), 7.28 (tm, J
=7.2 Hz, 1 H), 7.20 (d, J =7.7 Hz, 1 H), 3.93 (q, J =10.9 Hz, 2 H). 19
F
NMR (471 MHz, CDCl3)
δ
-63.3 (t,
J
=10.9 Hz, 3 F). 13C NMR
(126 MHz, CDCl3) δ 162.0, 144.7, 136.7, 135.8, 133.8, 132.9, 132.7,
132.3, 131.6, 128.7, 128.4, 127.6, 127.6, 127.4, 127.3, 127.1, 126.2 (q,
J =274.9 Hz), 125.4, 29.4 (q, J =32.2 Hz). IR (KBr): 3056, 2995, 2927,
2852, 1632, 1607, 1587, 1502, 1485, 1458, 1439, 1423, 1367, 1287,
1265, 1240, 1219, 1165, 1112, 1073, 945, 872, 838, 818, 789, 770,
734, 705, 665, 632 cm−1. HRMS-ESI (m/z) calcd. for C19H13F3NSe ([M
+H]+): 392.0160; found: 392.0178.
4.2.18. 6-((2,2,2-Trifluoroethyl)selanyl)benzofuro[3,2-k]phenanthridine
(3s)
White solid, 74.6 mg, 97% yield, a mixture of petroleum ether and
ethyl acetate (30:1 (v/v)) as eluents for column chromatography. M.p.:
190–192 °C. 1H NMR (500 MHz, CDCl3) δ 9.52 (m, 1 H), 8.21 (d, J
=8.4 Hz, 1 H), 8.13 (m, 1 H), 8.09 (d, J =7.6 Hz, 1 H), 8.06 (d, J
=8.4 Hz, 1 H), 7.82 (d, J =8.3 Hz, 1 H), 7.81-7.75 (m, 2 H), 7.61 (tm, J
=7.8 Hz, 1 H), 7.48 (t, J =7.6 Hz, 1 H), 4.35 (q, J =10.8 Hz, 2 H). 19F
4.2.14. 6-((2,2,2-Trifluoroethyl)selanyl)-[1,3]dioxolo[4,5-j]
phenanthridine (3o)
White solid, 74.6 mg, 97% yield, a mixture of petroleum ether and
ethyl acetate (30:1 (v/v)) as eluents for column chromatography. M.p.:
157–159 °C. 1H NMR (500 MHz, CDCl3) δ 8.28 (d, J =8.2 Hz, 1 H), 8.02
(d, J =8.2 Hz, 1 H), 7.85 (s, 1 H), 7.65 (t, J =7.2 Hz, 1 H), 7.57 (t, J
NMR (471 MHz, CDCl3)
δ
-63.6 (t,
J
=10.6 Hz, 3 F). 13C NMR
=7.9 Hz, 1 H), 7.41 (s, 1 H), 6.16 (s, 2 H), 4.29 (q, J =10.8 Hz, 2 H). 19
F
(126 MHz, CDCl3) δ 156.9, 153.4, 152.1, 144.3, 129.2, 128.7, 128.2,
127.4, 127.0, 126.2 (q, J =274.5 Hz), 126.0, 125.9, 123.6, 123.2,
121.6, 121.1, 121.0, 120.1, 120.0, 112.2, 25.8 (q, J =33.3 Hz). IR
(KBr): 3047, 3009, 2943, 2850, 1629, 1605, 1578, 1567, 1526, 1490,
1470, 1457, 1417, 1399, 1363, 1336, 1290, 1261, 1215, 1197, 1180,
1150, 1116, 1062, 1015, 862, 837, 824, 804, 769, 754, 747, 730, 704,
688, 667, 650, 631 cm−1. HRMS-ESI (m/z) calcd. for C21H13F3NOSe
([M+H]+): 432.0109; found: 432.0095.
NMR (471 MHz, CDCl3)
δ
-63.7 (t,
J
=10.9 Hz, 3 F). 13C NMR
(126 MHz, CDCl3) δ 151.9, 151.5, 148.4, 143.7, 130.0, 128.9, 128.3,
126.2, 126.1 (q, J =274.2 Hz), 123.6, 123.0, 122.0, 103.6, 102.2,
100.5, 25.7 (q, J =33.3 Hz). IR (KBr): 3072, 3044, 2995, 2954, 2924,
2823, 2782, 1634, 1611, 1572, 1522, 1500, 1481, 1463, 1445, 1417,
1378, 1294, 1264, 1250, 1236, 1206, 1184, 1108, 1056, 1040, 980,
945, 857, 835, 783, 762, 721, 705, 633, 612 cm−1. HRMS-ESI (m/z)
calcd. for C16H11F3NO2Se ([M+H]+): 385.9902; found: 385.9898.
4.2.19. 3-Methyl-6-((2,2,2-trifluoroethyl)selanyl)phenanthridine (3t)
Light yellow solid, 36.7 mg, 52% yield, a mixture of petroleum ether
and ethyl acetate (30:1 (v/v)) as eluents for column chromatography.
M.p.: 104–105 °C. 1H NMR (500 MHz, CDCl3) δ 8.52 (d, J =8.2 Hz,
1 H), 8.36 (d, J =8.3 Hz, 1 H), 8.07 (d, J =8.1 Hz, 1 H), 7.86 (s, 1 H),
7.82 (t, J =7.3 Hz, 1 H), 7.65 (t, J =7.4 Hz, 1 H), 7.44 (d, J =8.3 Hz,
1 H), 4.31 (q, J =10.8 Hz, 2 H), 2.59 (s, 3 H). 19F NMR (471 MHz,
CDCl3) δ -63.7 (t, J =10.6 Hz, 3 F). 13C NMR (126 MHz, CDCl3) δ 153.6,
144.2, 139.3, 132.5, 131.1, 128.6, 128.2, 127.3, 126.3, 126.2 (q, J
=274.8 Hz), 126.0, 122.4, 122.0, 121.0, 25.3 (q, J =33.3 Hz), 21.5. IR
(KBr): 3072, 3056, 3003, 2937, 2848, 1621, 1575, 1526, 1479, 1411,
1294, 1282, 1256, 1211, 1151, 1116, 1057, 954, 930, 885, 856, 832,
808, 776, 755, 721, 708, 685, 632, 603 cm−1. HRMS-ESI (m/z) calcd.
for C16H13F3NSe ([M+H]+): 356.0160; found: 356.0169.
4.2.15. 4-((2,2,2-Trifluoroethyl)selanyl)thieno[3,2-c]quinolone (3p)
White solid, 58.4 mg, 84% yield, a mixture of petroleum ether and
ethyl acetate (40:1 (v/v)) as eluents for column chromatography. M.p.:
79–81 °C. 1H NMR (500 MHz, CDCl3) δ 8.12 (d, J =8.3 Hz, 1 H), 8.05
(d, J =7.9 Hz, 1 H), 7.69 (t, J =7.6 Hz, 1 H), 7.60-7.56 (m, 2 H), 7.53
(d, J =5.4 Hz, 1 H), 4.32 (q, J =10.7 Hz, 2 H). 19F NMR (471 MHz,
CDCl3) δ -63.9 (t, J =10.9 Hz, 3 F). 13C NMR (126 MHz, CDCl3) δ 147.7,
144.4, 144.0, 133.1, 129.0, 128.7, 126.5, 126.5, 126.1 (q,
J
=274.3 Hz), 123.3, 123.2, 122.8, 24.9 (q, J =33.7 Hz). IR (KBr): 3108,
3005, 2963, 2940, 1609, 1550, 1540, 1504, 1468, 1446, 1402, 1389,
1338, 1293, 1264, 1214, 1151, 1138, 1112, 1063, 974, 947, 861, 833,
802, 781, 754, 733, 727, 707, 680, 631 cm−1. HRMS-ESI (m/z) calcd.
for C13H9F3NSSe ([M+H]+): 347.9568; found: 347.9579.
4.2.16. 4-((2,2,2-Trifluoroethyl)selanyl)thieno[2,3-c]quinolone (3q)
White solid, 66.6 mg, 96% yield, a mixture of petroleum ether and
ethyl acetate (40:1 (v/v)) as eluents for column chromatography. M.p.:
103–105 °C. 1H NMR (500 MHz, CDCl3) δ 8.21 (dd, J = 8.1, 0.9 Hz,
1 H), 8.14 (d, J =8.3 Hz, 1 H), 7.96 (d, J =5.3 Hz, 1 H), 7.81 (d, J
=5.3 Hz, 1 H), 7.69 (tm, J =7.8 Hz, 1 H), 7.60 (tm, J =7.6 Hz, 1 H),
4.32 (q, J =10.7 Hz, 2 H). 19F NMR (471 MHz, CDCl3) δ -64.0 (t, J
=10.5 Hz, 3 F). 13C NMR (126 MHz, CDCl3) δ 145.8, 144.9, 141.5,
134.0, 131.0, 128.8, 128.4, 126.3, 126.0 (q, J =274.6 Hz), 123.5,
123.4, 122.1, 25.4 (q, J =33.8 Hz). IR (KBr): 3116, 3059, 3003, 2940,
1612, 1562, 1543, 1494, 1456, 1432, 1412, 1384, 1331, 1296, 1276,
1244, 1219, 1189, 1158, 1134, 1111, 1092, 1069, 1051, 959, 899, 845,
834, 788, 759, 727, 709, 669, 640, 633 cm−1. HRMS-ESI (m/z) calcd.
for C13H9F3NSSe ([M+H]+): 347.9568; found: 347.9567.
4.2.20. 2-Chloro-6-((2,2,2-trifluoroethyl)selanyl)phenanthridine (3u)
White solid, 33.2 mg, 44% yield, a mixture of petroleum ether and
ethyl acetate (60:1 (v/v)) as eluents for column chromatography. M.p.:
117–119 °C. 1H NMR (500 MHz, CDCl3) δ 8.44 (d, J =8.3 Hz, 1 H), 8.39
(d, J =2.1 Hz, 1 H), 8.07 (d, J =8.1 Hz, 1 H), 7.96 (d, J =8.7 Hz, 1 H),
7.85 (t, J =8.0 Hz, 1 H), 7.71 (t, J =7.7 Hz, 1 H), 7.62 (dd, J = 8.7,
2.2 Hz, 1 H), 4.27 (q, J =10.8 Hz, 2 H). 19F NMR (471 MHz, CDCl3) δ
-63.7 (t, J =10.6 Hz, 3 F). 13C NMR (126 MHz, CDCl3) δ 154.5, 142.4,
132.3, 131.5, 131.2, 130.3, 129.4, 128.4, 126.6, 126.1, 126.1 (q, J
=274.6 Hz), 124.3, 122.6, 121.9, 25.4 (q, J =33.4 Hz). IR (KBr): 3068,
3016, 2952, 2844, 1603, 1574, 1562, 1518, 1483, 1424, 1400, 1332,
1293, 1257, 1217, 1197, 1163, 1116, 1085, 1065, 1041, 952, 942, 870,
862, 853, 828, 758, 734, 719, 707, 632, 621 cm−1. HRMS-ESI (m/z)
calcd. for C15H10ClF3NSe ([M+H]+): 375.9614; found: 375.9627.
7

C.-L. Zhao, et al.
JournalofFluorineChemistry226(2019)109360
4.2.21. 7-Methyl-1-((2,2,2-trifluoroethyl)selanyl)-3,4-dihydroisoquinoline
(3w)
Appendix A. Supplementary data
Light yellow solid, 13.1 mg, 21% yield, a mixture of petroleum ether
and ethyl acetate (40:1 (v/v)) as eluents for column chromatography.
M.p.: 84–86 °C. 1H NMR (500 MHz, CDCl3) δ 7.31 (s, 1 H), 7.21 (d, J
=7.6 Hz, 1 H), 7.10 (d, J =7.6 Hz, 1 H), 3.84 (q, J =10.8 Hz, 2 H), 3.79
(t, J =7.4 Hz, 2 H), 2.72 (t, J =7.4 Hz, 2 H), 2.38 (s, 3 H). 19F NMR
(471 MHz, CDCl3) δ -63.7 (t, J =10.8 Hz, 3 F). 13C NMR (126 MHz,
CDCl3) δ 158.2, 137.0, 133.8, 132.1, 129.7, 127.4, 126.1 (q, J
=274.0 Hz), 125.8, 49.6, 26.0, 24.5 (q, J =33.0 Hz), 21.2. IR (KBr):
3002, 2937, 2863, 1604, 1494, 1461, 1402, 1347, 1330, 1291, 1266,
1254, 1226, 1214, 1161, 1114, 1066, 1019, 981, 935, 879, 871, 838,
Supplementary material related to this article can be found, in the on-
line version, at doi:https://doi.org/10.1016/j.jfluchem.2019.109360.
References
[1] (a) Selected books and reviews, P. Kirsch, Modern Fluoroorganic Chemistry:
Synthesis, Reactivity, Applications, 2nd ed., Wiley-VCH, Weinheim, 2013;
(b) I. Ojima (Ed.), Fluorine in Medicinal Chemistry and Chemical Biology, Wiley-
Blackwell, 2009;
(c) G.J. Puts, P. Crouse, B.M. Ameduri, Chem. Rev. 119 (2019) 1763–1805;
(d) R. Ragni, A. Punzi, F. Babudri, G.M. Farinola, Eur. J. Org. Chem. (2018)
3500–3519 2018.
815, 718, 706, 689, 632 cm−1
. HRMS-ESI (m/z) calcd. for
[2] (a) Selected reviews, M.-C. Gagnon, M. Auger, J.-F. Paquin, Org. Biomol. Chem. 16
(2018) 4925–4941;
C
12H12F3NNaSe ([M + Na]+): 329.0021; found: 329.0019.
(b) E.V. Nosova, G.N. Lipunova, V.N. Charushin, O.N. Chupakhin, J. Fluorine
Chem. 212 (2018) 51–106;
4.2.22. 6,7-Dimethyl-1-((2,2,2-trifluoroethyl)selanyl)-3,4-
(c) Y. Zhu, J. Han, J. Wang, N. Shibata, M. Sodeoka, V.A. Soloshonok,
J.A.S. Coelho, F.D. Toste, Chem. Rev. 118 (2018) 3887–3964;
(d) N.A. Meanwell, J. Med. Chem. 61 (2018) 5822–5880;
(e) K. Haranahalli, T. Honda, I. Ojima, J. Fluorine Chem. 217 (2019) 29–40;
(f) A.M. Remete, M. Nonn, S. Fustero, F. Fülöp, L. Kiss, Tetrahedron 74 (2018)
6367–6418;
dihydroisoquinoline (3x)
White solid, 29.4 mg, 46% yield, a mixture of petroleum ether and
ethyl acetate (40:1 (v/v)) as eluents for column chromatography. M.p.:
85–87 °C. 1H NMR (500 MHz, CDCl3) δ 7.29 (s, 1 H), 7.00 (s, 1 H), 3.85
(q, J =10.9 Hz, 2 H), 3.79 (t, J =7.3 Hz, 2 H), 2.71 (t, J =7.3 Hz, 2 H),
2.30 (s, 3 H), 2.30 (s, 3 H). 19F NMR (471 MHz, CDCl3) δ -63.7 (t, J
=10.9 Hz, 3 F). 13C NMR (100 MHz, CDCl3) δ 158.1, 140.7, 135.5,
134.2, 128.9, 127.8, 126.4, 126.2 (q, J =274.4 Hz), 49.7, 25.9, 24.4 (q,
J =33.2 Hz), 20.0, 19.6. IR (KBr): 3193, 3060, 3007, 2972, 2923, 2860,
1663, 1609, 1560, 1496, 1480, 1458, 1423, 1400, 1338, 1327, 1310,
1291, 1268, 1215, 1109, 1067, 1021, 945, 921, 873, 832, 718, 706,
632, 600 cm−1. HRMS-ESI (m/z) calcd. for C13H15F3NSe ([M+H]+):
322.0316; found: 322.0320.
(g) S. Huhmann, B. Koksch, Eur. J. Org. Chem. (2018) 3667–3679 2018;
(h) J. Krüll, M.R. Heinrich, Asian J. Org. Chem. 8 (2019) 576–590.
[3] (a) J.-B. Han, J.-H. Hao, C.-P. Zhang, H.-L. Qin, Curr. Org. Chem. 19 (2015)
1554–1565 Selected reviews;
(b) K. Uneyama, T. Yamazaki, J. Fluorine Chem. 203 (2017) 3–30;
(c) Q.-Y. Han, C.-L. Zhao, C.-P. Zhang, Chin. J. Org. Chem. 39 (2019) 84–94;
(d) H.-X. Song, Q.-Y. Han, C.-L. Zhao, C.-P. Zhang, Green Chem. 20 (2018)
1662–1731.
[4] (a) A. van Oeveren, M. Motamedi, N.S. Mani, K.B. Marschke, F.J. Lopez,
W.T. Schrader, A. Negro-Vilar, L. Zhi, J. Med. Chem. 49 (2006) 6143–6146 Selected
examples;
(b) F. Xu, M. Zacuto, N. Yoshikawa, R. Desmond, S. Hoerrner, T. Itoh, M. Journet,
G.R. Humphrey, C. Cowden, N. Strotman, P. Devine, J. Org. Chem. 75 (2010)
7829–7841;
4.2.23. 6,7-Dimethoxy-1-((2,2,2-trifluoroethyl)selanyl)-3,4-
dihydroisoquinoline (3y)
(c) R. Gujjar, F.E. Mazouni, J. White, S. Creason, D.M. Shackleford, X. Deng,
W.N. Charman, I. Bathurst, J. Burrows, D.M. Floyd, D. Matthews, F.S. Buckner,
S.A. Charman, M.A. Phillips, P.K. Rathod, J. Med. Chem. 54 (2011) 3935–3949;
(d) R. Vorberg, N. Trapp, D. Zimmerli, B. Wagner, H. Fischer, N.A. Kratochwil,
M. Kansy, E.M. Carreira, K. Müller, ChemMedChem 11 (2016) 2216–2239.
[5] (b) H. Zhang, H.-Y. Wang, Y. Luo, C. Chen, Y. Cao, P. Chen, Y.-L. Guo, Y. Lan,
G. Liu, ACS Catal. 8 (2018) 2173–2180;
White solid, 54.6 mg, 78% yield, a mixture of petroleum ether and
ethyl acetate (40:1 (v/v)) as eluents for column chromatography. M.p.:
110–112 °C. 1H NMR (500 MHz, CDCl3) δ 7.00 (s, 1 H), 6.69 (s, 1 H),
3.91 (s, 3 H), 3.91 (s, 3 H), 3.84 (q, J =10.9 Hz, 2 H), 3.76 (t, J
=7.5 Hz, 2 H), 2.68 (t, J =7.5 Hz, 2 H). 19F NMR (471 MHz, CDCl3) δ
-63.7 (t, J =10.9 Hz, 3 F). 13C NMR (126 MHz, CDCl3) δ 157.4, 151.6,
147.9, 130.5, 126.1 (q, J =274.5 Hz), 122.6, 110.3 108.6, 56.2, 56.1,
49.4, 26.0, 24.6 (q, J =33.2 Hz). IR (KBr): 3192, 2996, 2966, 2942,
2921, 2860, 2836, 1657, 1605, 1570, 1513, 1471, 1438, 1410, 1348,
1283, 1270, 1256, 1226, 1214, 1198, 1124, 1054, 930, 858, 836, 801,
632 cm−1. HRMS-ESI (m/z) calcd. for C13H15F3NO2Se ([M+H]+):
354.0215; found: 354.0227.
(a) ref 3a and the references cited therein.
(c) X. Zhang, C. Yang, Adv. Synth. Catal. 357 (2015) 2721–2727;
(d) S.-Y. Yan, Z.-Z. Zhang, B.-F. Shi, Chem. Commun. (Camb.) 53 (2017)
10287–10290;
(e) Y. Yang, Q. Zhou, J. Cai, T. Xue, Y. Liu, Y. Jiang, Y. Su, L. Chung, D.A. Vicic,
Chem. Sci. 10 (2019) 5275–5282;
(f) X. Yu, S.M. Cohen, J. Am. Chem. Soc. 138 (2016) 12320–12323;
(g) Y. Ohtsuka, T. Yamakawa, J. Fluorine Chem. 185 (2016) 96–102;
(h) H. Luo, G. Wu, Y. Zhang, J. Wang, Angew. Chem. Int. Ed. 54 (2015)
14503–14507;
(i) X. Wang, D. Huang, K.-H. Wang, J. Liu, W. Zong, J. Wang, Y. Su, Y. Hu, Appl
Organometal Chem. (2019) e4995;
4.2.24. 5-((2,2,2-Trifluoroethyl)selanyl)-7,8-dihydro-[1,3]dioxolo[4,5-g]
isoquinoline (3z)
(j) M. Zhu, X. Han, W. Fu, Z. Wang, B. Ji, X.-Q. Hao, M.-P. Song, C. Xu, J. Org.
Chem. 81 (2016) 7282–7287;
(k) E.-J. Han, Y. Sun, Q. Shen, Q.-Y. Chen, Y. Guo, Y.-G. Huang, Org. Chem. Front.
2 (2015) 1379–1387;
White solid, 48.2 mg, 72% yield, a mixture of petroleum ether and ethyl
acetate (10:1 (v/v)) as eluents for column chromatography. M.p.:
126–128 °C. 1H NMR (500 MHz, CDCl3) δ 7.02 (s, 1 H), 6.67 (s, 1 H), 5.99
(s, 2 H), 3.82 (q, J =10.9 Hz, 2 H), 3.73 (t, J =7.5 Hz, 2 H), 2.66 (t, J
(l) X.-J. Tang, C.S. Thomoson, W.R. Dolbier, Jr. Org. Lett. 16 (2014) 4594–4597;
(m) K.G. Andrews, R. Faizova, R.M. Denton, Nat. Commun. 8 (2017) 15913
[6] (a) B.L. Tóth, S. Kovács, G. Sályi, Z. Novák, Angew. Chem. Int. Ed. 55 (2016)
1988–1992;
=7.6 Hz, 2 H). 19F NMR (471 MHz, CDCl3) δ -63.7 (t, J =11.0 Hz, 3 F). 13
C
(b) J. Yang, Q.-Y. Han, C.-L. Zhao, T. Dong, Z.-Y. Hou, H.-L. Qin, C.-P. Zhang, Org.
Biomol. Chem. 14 (2016) 7654–7658;
NMR (126 MHz, CDCl3) δ 157.3, 149.8, 146.7, 132.4, 126.1 (q, J
=274.6 Hz), 123.9, 107.9, 105.9, 101.6, 49.2, 26.7, 24.7 (q, J =33.2 Hz).
IR (KBr): 3026, 2945, 2906, 2860, 1622, 1592, 1505, 1482, 1403, 1365,
1339, 1324, 1294, 1270, 1241, 1213, 1173, 1158, 1108, 1078, 1063, 1039,
952, 937, 856, 838, 734, 709, 632, 609 cm−1. HRMS-ESI (m/z) calcd. for
(c) S. Kovács, B.L. Tóth, G. Borsik, G. Borsik, T. Bihari, N.V. May, A. Stirling,
Z. Novák, Adv. Synth. Catal. 359 (2017) 527–532;
(d) A.J. Borah, Z. Shi, Chem. Commun. (Camb.) 53 (2017) 3945–3948;
(e) M. Maraswami, S. Pankajakshan, G. Chen, T.P. Loh, Org. Lett. 19 (2017)
4223–4226;
(f) Q.-Y. Han, X. Hu, X.-S. Xue, C.-L. Zhao, C.-P. Zhang, Asian J. Org. Chem. 8
(2019) 665–670.
C
12H11F3NO2Se ([M+H]+): 337.9902; found: 337.9893.
[7] (b) C.-L. Zhao, Q.-Y. Han, C.-P. Zhang, Org. Lett. 20 (2018) 6480–6484;
(a) ref 3b and the references cited therein.
Acknowledgements
(c) S. Maiti, J. Kim, J.-H. Park, D. Nam, J.B. Lee, Y.-J. Kim, J.-M. Kee, J.K. Seo, K.
Myung, J.-U. Rohde, W. Choe, O.-H. Kwon, S.Y. Hong, J. Org. Chem. 84 (2019)
6737–6751
We thank the National Natural Science Foundation of China (21602165,
51503037), the “Chutian Scholar” Program from Department of Education
of Hubei Province (China), the “Hundred Talent” Program of Hubei
Province (China), and the Chongqing Research Program of Basic and
Frontier Technology (cstc2018jcyjAX0106) for financial supports.
[8] (a) E.V. Costa, M.L.B. Pinheiro, B.H.L. Maia, M.B.P. Soares, N.S.F.A. Marques,
A.L.T.G. Ruiz, G.M. Marchetti, D.J.E. Carvalho, C.O.S. Costa, A.F.C. Galvao,
N.P. Lopes, H.H.F. Koolen, D.P. Bezerra, A. Barison, J. Nat. Prod. 79 (2016)
1524–1531;
(b) Z.-H. Zhang, H.-J. Zhang, A.-J. Deng, B. Wang, Z.-H. Li, Y. Liu, L.-Q. Wu, W.-
8

C.-L. Zhao, et al.
JournalofFluorineChemistry226(2019)109360
J. Wang, H.-L. Qin, J. Med. Chem. 58 (2015) 7557–7571;
Chem. Soc. Perkin Trans. I 1 (1976) 33–38;
(c) A. Debono, B. Capuano, P.J. Scammells, J. Med. Chem. 58 (2015) 5699–5727;
(d) K.W. Bentley, Nat. Prod. Rep. 23 (2006) 444–463;
(c) P.A.S. Smith, R.O. Kan, Organic Synth. 44 (1964) 91.
[13] (a) A.E. Feiring, J. Org. Chem. 45 (1980) 1958–1961;
(b) R. Khajuria, K.K. Bhasin, R.D. Verma, J. Fluorine Chem. 67 (1994) 61–65;
(c) J. Dong, Z. Li, Z. Weng, Org. Biomol. Chem. 16 (2018) 9269–9273;
(d) T. Yamamoto, E. Moriura, A. Sawa, M. Yoshimatsu, Chem. Lett. 37 (2008)
1046–1047;
(e) R. Sanz, Y. Fernández, M.P. Castroviejo, A. Pérez, F.J. Fañanás, Eur. J. Org.
Chem. (2007) 62–69;
(f) T. Nakanishi, M. Suzuki, Org. Lett. 1 (1999) 985–988;
(g) L.-M. Tumir, M.R. Stojković, I. Piantanida, Beilstein J. Org. Chem. 10 (2014)
2930–2954;
(e) J. Li, C. Ma, D. Xing, W. Hu, Org. Lett. 21 (2019) 2101–2105;
(f) S. Piettre, Z. Janousek, H.G. Viehe, Synthesis (1982) 1083–1084;
(g) C. Ghiazza, C. Monnereau, L. Khrouz, M. Médebielle, T. Billard, A. Tlili, Synlett
30 (2019) 777–782;
(h) S. Haider, A.G. Chittiboyina, I.A. Khan, Curr. Org. Chem. 22 (2018) 148–164;
(i) Z.-X. Qing, P. Yang, Q. Tang, P. Cheng, X.-B. Liu, Y.-J. Zheng, Y.-S. Liu, J.-
G. Zeng, Curr. Org. Chem. 21 (2017) 1920–1934;
(j) M. Chrzanowska, A. Grajewska, M.D. Rozwadowska, Chem. Rev. 116 (2016)
12369–12465.
(h) Q.-Y. Han, C.-L. Zhao, T. Dong, J. Shi, K.-L. Tan, C.-P. Zhang, Org. Chem. Front.
6 (2019) 2732–2737.
[9] B. Zhang, A. Studer, Chem. Soc. Rev. 44 (2015) 3505–3521.
[10] (a) W. Guo, S. Li, L. Tang, M. Li, L. Wen, C. Chen, Org. Lett. 17 (2015) 1232–1235;
(b) W.-S. Guo, Q. Dou, J. Hou, L.-R. Wen, M. Li, J. Org. Chem. 82 (2017)
7015–7022;
[14] T. Umemoto, Y. Gotoh, Bull. Chem. Soc. Jpn. 64 (1991) 2008–2010.
[15] G.L. Tolnai, A. Székely, Z. Makó, T. Gáti, J. Daru, T. Bihari, A. Stirling, Z. Novák,
Chem. Commun. (Camb.) 51 (2015) 4488–4491.
[16] (a) B.J. Stokes, B. Jovanović, H. Dong, K.J. Richert, R.D. Riell, T.G. Driver, J, . Org.
Chem. 74 (2009) 3225–3228;
(c) L.-R. Wen, Q. Dou, Y.-C. Wang, J.-W. Zhang, W.-S. Guo, M. Li, J. Org. Chem. 82
(2017) 1428–1436.
(b) P. Xiao, J. Rong, C. Ni, J. Guo, X. Li, D. Chen, J. Hu, Org. Lett. 18 (2016)
5912–5915.
[11] (a) H. Heimgartner, Y. Zhou, P.K. Atanassov, G.L. Sommen, Phosphorus Sulfur
Silicon Relat. Elem. 183 (2008) 840–855;
[17] G. Prabhu, L. Santhosh, G. Nagendra, V. Panduranga, V.V. Sureshbabu,
ChemistrySelect 2 (2017) 1202–1206.
(b) D.R. Garud, M. Koketsu, H. Ishihara, Molecules 12 (2007) 504–535;
(c) M. Ninomiya, D.R. Garud, M. Koketsu, Heterocycles 81 (2010) 2027–2055.
[12] (a) L.-R. Wen, Q. Dou, Y.-C. Wang, J.-W. Zhang, W.-S. Guo, M. Li, J. Org. Chem. 82
(2017) 1428–1436;
[18] A.K. Sharma, A. Sharma, D. Desai, S.V. Madhunapantula, S.J. Huh, G.P. Robertson,
S. Amin, J. Med. Chem. 51 (2008) 7820–7826.
[19] W.L.F. Armarego, C.L.L. Chai, Purification of Laboratory Chemicals, 5th ed.,
Butterworth Heinemann, Oxford, 2003.
(b) M.W. Gittos, M.R. Robinson, J.P. Verge, R.V. Davies, B. Iddon, H. Suschitzky, J.
9