Visible-light-induced photocatalytic trifluoromethylation/1,2-carbon migration sequences for the synthesis of CF3-substituted cyclic ketones

Article abstract of DOI:10.1016/j.jfluchem.2015.08.008

A visible-light-induced photoredox trifluoromethylation/1,2-carbon migration sequence of alkenols is described. This approach provides a mild and operationally simple access to the synthesis of CF₃-substituted cyclic ketones via trifluoromethyl

Full text of DOI:10.1016/j.jfluchem.2015.08.008

Accepted Manuscript
Title: Visible-Light-Induced Photocatalytic
Trifluoromethylation/1,2-Carbon Migration Sequences for the
Synthesis of CF3-Substituted Cyclic Ketones
Author: Saet Byeol Woo Dae Young Kim
PII:
S0022-1139(15)00252-3
DOI:
Reference:
http://dx.doi.org/doi:10.1016/j.jfluchem.2015.08.008
FLUOR 8639
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Received date:
Revised date:
Accepted date:
20-6-2015
2-8-2015
8-8-2015
Please cite this article as: S.B. Woo, D.Y. Kim, Visible-Light-Induced Photocatalytic
Trifluoromethylation/1,2-Carbon Migration Sequences for the Synthesis of
CF3-Substituted Cyclic Ketones, Journal of Fluorine Chemistry (2015),
http://dx.doi.org/10.1016/j.jfluchem.2015.08.008
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Graphical Abstract
Visible-Light-Induced Photocatalytic Trifluoromethylation/1,2-Carbon Migration
Sequences for the Synthesis of CF3-Substituted Cyclic Ketones
Saet Byeol Woo and Dae Young Kim
O
Ru(phen)3Cl2
(2 mol %)
OH
Ar
+
Ar
CF3
S
acetone, 15 min
blue LEDs
BF4
CF3
66-77% yields
Communications
Visible-Light-Induced Photocatalytic Trifluoromethylation/1,2-Carbon Migration
Sequences for the Synthesis of CF3-Substituted Cyclic Ketones
Saet Byeol Woo and Dae Young Kim
Department of Chemistry, Soonchunhyang University, Asan, Chungnam 336-745, Republic of Korea
*Corresponding author. Tel: +82-41-530-1244; fax: +82-41-530-1247.
E-mail: dyoung@sch.ac.kr
Abstract:
Page 1 of 20

A visible-light-induced photoredox trifluoromethylation/1,2-carbon migration sequences of
alkenols is described. This approach provides a mild and operationally simple access to the
synthesis of CF3-substituted cyclic ketones via trifluoromethylation and 1,2-carbon migration
of 1-(1-arylvinyl)cyclobutanol derivatives.
Highlight
1. We have developed the photocatalyzed trifluoromethylation and 1,2-
carbon migration of 1-(1-arylvinyl)cyclobutanol derivatives.
2. Moderate to high yields (3a-3f, 66-77%) observed under mild reaction
conditions.
3. This reaction requires short reaction time and has broad substrate scope
including 6 and 7.
Keywords: Trifluoromethylation, Photocatalysis, Radical reaction, 1,2-Carbon migration
1. Introduction
The chemistry of fluorinated molecules is a rapidly developing research area because
of their their utility as medicines, agrochemicals, and functional materials [1]. Especially, the
trifluoromethyl group is an important structural motif found in pharmaceuticals,
agrochemicals, and biologically active compounds [2]. The introductionof a trifluoromethyl
group into organic compounds usually leads to improvement of their biological and
physiological characteristics due to unique physical and chemical properties [3]. For example,
the incorporated trifluoromethyl group could improve their chemical and metabolic stability
and increase their bioavailability [4]. Consequently, considerable effort has been contributed
toward the development of expedient methods for C-CF3 bond formation [5]. Among the
most direct approaches for the construction of C-CF3 bonds is the trifluoromethylation of
alkenes by using the trifluoromethyl radical source in the presence of transition metal
complexes or organic oxidants as external initiators through radical intermediate [6].
The application of visible-light photoredox catalysis has emerged as a novel and
Page 2 of 20

powerful tool for chemical transformations in organic chemistry, because of its attractive
features such as environmental compatibility, mild and green conditions, excellent functional
group tolerance, and versatility in promoting various reactions [7]. The visible-light-induced
photocatalytic difunctionalization of alkenes provides a useful approach to obtain various
diversely functionalized molecules [8]. The photocatalytic difunctionalization of alkenes with
suitable trifluoromethyl sources also enable the facile incorporation of the trifluoromethyl
moiety into valuable organic compounds [9]. The application of such a visible-light-induced
photocatalytic strategy to achieve functionalized trifluoromethyl-containing compounds is
highly desirable. Recently, several groups independently reported the preparation of -
trifluoromethyl ketones from allylic alcohols via 1,2-aryl migration using Togni’s reagent in
the presence of transition metal complexes [10] and Langlois’ reagent under metal-free
condition [11]. After completion of this work and during the preparation of this manuscript, a
paper by Glorius group on visible-light photoredox catalyzed semipinacol-type
rearrangement via trifluomethylation/ring expansion was published [12]. This reported
protocol requires 1.2 eq. of trimethylsilyl trifluoromethanesulfonate (TMSOTf) and long
reaction time (8 h).
In the framework of our research program on the internal redox reaction and
cyclization sequences, we recently reported the C-H bond functionalization via 1,5-hydride
transfer and cyclization cascade [13]. In this communication, we wish to describe visible-
light-induced photoredox trifluoromethylation/1,2-carbon migration [14] sequences of 1-(1-
arylvinyl)cyclobutanol derivatives for the synthesis of trifluoromethyl-substituted cyclic
ketones.
2. Results and discussion
Page 3 of 20

To determine suitable reaction conditions for the visible-light-induced photocatalytic
trifluoromethylation/1,2-carbon migration of 1-(1-arylvinyl)cyclobutanols, we examined the
visible-light-induced photocatalytic reaction of 1-(1-phenylvinyl)cyclobutanol (1a) with
electrophilic trifluromethylation reagents (2) in the presence of 5 mol% of Ru(phen)3Cl2
under visible-light irradiation from blue LEDs (5 W, max = 455 nm) in dichloromethane at
room temperature (Table 1). By screening trifluromethylation reagents 2a-2d, we found that
Umemoto’s reagent 2c was the best trifluromethylation reagent for this
trifluoromethylation/1,2-carbon migration, affording the corresponding product 3a in 70%
yield (Table 1, entry 3). Next, we examined the effect of photocatalysts in dichloromethane
(entries 3 and 5-9). A. survey of the different photocatalysts indicate that Ru(bpy)3(PF6)2,
.
Ru(bpy)3Cl2 6H2O, and fluorescein gave moderate to low yields (68-22%), while eosin Y and
eosin Y.Na2 gave trace amount of product 3a. In addition, the solvent was found to have an
effect on reactivity. Among the solvents probed (entries 3 and 10-14), the best result was
achieved when the reaction was conducted in acetone (77% yield, entry 12). The present
catalytic system tolerates photocatalyst loading down to 2 mol % without compromising the
yield (entries 12 and 15).The control experiment showed that the reaction could not proceed
in the absence of a photocatalyst and visible-light (entries 16-17).
Page 4 of 20

Table 1. Optimization of the reaction conditionsa
O
OH
Ph
photocatalyst (5 mol %)
CF3
+ CF3 source
Ph
solvent, rt, blue LEDs
1a
2
3a
O
O
O
I
I
S
S
BF4
OTf
CF3
CF3
CF3
CF3
2a
2b
2c
2d
yield
entry
2
photocatalyst
solvent
time
(%)b
trace
1
2
2a
2b
2c
2d
2c
2c
2c
Ru(phen)3Cl2
Ru(phen)3Cl2
Ru(phen)3Cl2
Ru(phen)3Cl2
Ru(bpy)3(PF6)2
Ru(bpy)3Cl2·6H2O
Fluorescein
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
14 h
10 h
trace
70
3
15 min
15 min
15 min
15 min
1 h
4
60
5
24
6
7c
68
22
8c
2c
2c
2c
2c
2c
2c
2c
2c
2c
2c
Eosin Y
Eosin Y·Na2
Ru(phen)3Cl2
Ru(phen)3Cl2
Ru(phen)3Cl2
Ru(phen)3Cl2
Ru(phen)3Cl2
Ru(phen)3Cl2
-
CH2Cl2
CH2Cl2
CH3Cl
CH2CH2Cl2
acetone
CH3CN
DMF
acetone
acetone
acetone
6 h
6 h
1 h
trace
trace
7
27
77
36
26
77
0
9c
10
11
12
13
14
15d
16
17e
1 h
15 min
30 min
30 min
15 min
1 h
Ru(phen)3Cl2
1 h
0
a
Reaction conditions: 1-(1-phenylvinyl)cyclobutanol (1a, 0.3 mmol), CF3 reagent (2, 0.6 mmol), photocatalyst
b
c
(0.015 mmol), solvent (3.0 mL) at room temperature under visible-light irradiation. Isolated yield. 10 mol%
photocatalyst loading. d 2 mol% photocatalyst loading. e The reaction was performed in the dark.
Page 5 of 20

With optimal reaction conditions in hand, we investigated the scope of this visible-
light-induced photocatalytic reaction of 1-(1-phenylvinyl)cyclobutanolderivatives 1 with
electrophilic trifluromethylation reagent (2c) in the presence of 2 mol% of Ru(phen)3Cl2
under light irradiation from blue LEDs (5 W, max = 455 nm) in acetone at room temperature.
As it can be seen by the results summarized in Table 2, various 1-(1-
phenylvinyl)cyclobutanols 1 with electron-withdrawing or electron-donating aryl groups
furnished the corresponding migration products with moderate to good yields (3a–3f). 3-(1-
Phenylvinyl)oxetan-3-ol (1g) afforded the corresponding product 3g in low yield. Also, 1-
(1H-inden-3-yl)cyclobutanol (1h) and 1-(3,4-dihydronaphthalen-1-yl)cyclobutanol (1i) gave
the desired products 3h-3i in moderate to low yields with 2:1 dr.
Page 6 of 20

Table 2. Variation of substrates 1a,b
R1
O
Ru(phen)3Cl2
(2 mol %)
Ar
CF3
+
R2
OH2
R2
R3
Ar
S
acetone, 15 min
blue LEDs
R3
BF4
R1
CF3
3
1
2c
___________________________________________________
O
O
O
F
Me
F3C
F3C
F3C
3b, 73%
3a, 77%
3c, 66%
Cl
F
O
O
O
F3C
F3C
F3C
3e
3f
3d
, 70%
, 70%
, 73%
O
O
O
CF3
CF3
O
F3C
3g, 25%
3h
, 42% (2:1 dr)
3i, 37% (2:1 dr)
___________________________________________________
a
Reaction conditions: cyclobutanols (1, 0.3 mmol), CF3 reagent (2a, 0.6 mmol), Ru(phen)3Cl2 (0.006 mmol),
acetone (3.0 mL) at room temperature under visible-light irradiation. b Isolated yields.
Page 7 of 20

Furthermore, 9-(1-phenylvinyl)-9H-fluoren-9-ol 4 derived from fluoreone and allyl
alcohol 6 were also used as a substrate in this visible-light-induced photocatalytic reaction
under the optimal conditions. It was found that the corresponding products 5 and 7 were
obtained in 82% and 48% yields (Scheme 1).
O
OH
Ru(phen)3Cl2
(2 mol %)
Ph
Ph
CF3
2c
+
acetone, 15 min
blue LEDs
4
5
(82% yield)
O
Ru(phen)3Cl2
(2 mol %)
OH
Ph
Ph
Ph
CF3
2c
+
acetone, 15 min
blue LEDs
Ph
7 (48% yield)
6
Scheme 1. Visible-light-induced photocatalytic trifluoromethylation/1,2-carbon migration of
4 and 6.
Page 8 of 20

To get an insight of the mechanism of this transformation, a radical-trapping
experiment was carried out. It was found that no product was detected in the presence of a
radical inhibitor TEMPO. Based on this result, we propose a plausible mechanism for the
reaction in Figure 1. A photocatalyst Ru(phen)32+ undergoes a metal to ligand charge transfer
process by visible-light to produce the excited state Ru*(phen)32+A single electron transfer
process then occurs to trifluormethylation reagent 2c would generate Ru(phen)33+ and an CF3
radical. Subsequently, CF3 radical will react with substrate 1 to generate intermediate I,
which undergoes single electron transfer from Ru(phen)33+ and intermediate I generate to
cation II. A 1,2-carbon migration of cation II afford the product 3.
2c
S
BF4
CF3
2+
Ru*(phen)3
excited state
S
CF3
visible
light
3+
Ru(phen)3
R1
Ar
CF3
R1
Ar
OH
R2
OH
R2
R3
R3
2+
Ru(phen)3
I
1
ground state
R1
Ar
CF3
O
Ar
CF3
R2
OH
R2
R3
R3
R1
II
3
Figure 1. Proposed reaction mechanism.
Page 9 of 20

3. Conclusions
In conclusion, we have developed the visible-light-induced photoredox-catalyzed
trifluoromethylation and 1,2-carbon migration sequences of 1-(1-arylvinyl)cyclobutanol
derivatives using Ru(phen)3Cl2 and Umemoto’s reagent 2c under mild reaction conditions. It
provides an efficient method for the synthesis of CF3-substituted cyclic ketone derivatives.
The approach offers a quick and convenient way to prepare CF3-substituted cyclic ketone
derivatives as compared to the recently reported methods [12]. Further study on asymmetric
version of the visible-light-induced photoredox-catalyzed trifluoromethylation and 1,2-carbon
migration are currently underway in our laboratory.
4. Experimental
4.1.General information
All commercial reagents and solvents were used without purification. TLC analyses
were carried out on pre-coated silica gel plates with F254 indicator. Visualization was
accomplished by UV light (254 nm), I2, p-anisaldehyde, ninhydrin, and phosphomolybdic
acid solution as an indicator. Purification of reaction products was carried out by flash
1
chromatography using E. Merck silica gel 60 (230-400 mesh). H NMR,13C NMR, and19F
NMRspectra were recorded at 400 MHz, 100 MHz, 376 MHzrespectively, on a Jeol ECS 400
MHz NMR spectrometer. Chemical shift values () are reported in ppm relative to Me4Si as
the internal references and PhCF3 as the external references. Mass spectra were measured on
Jeol HX110/110A using electrospray ionization technique.
Page 10 of 20

4.2. General procedure for the visible-light-induced photocatalytic trifluoromethylation/1,2-
carbon migration sequences for the synthesis of CF3-substituted cyclic ketones
An oven-dried Schlenk tube was equipped with a magnetic stir bar, 1-(1
arylvinyl)cyclobutanol derivatives (1, 0.3 mmol), Ru(phen)3Cl2 (0.006 mmol), 5-
(trifluoromethyl)dibenzothiophenium tetrafluoroborate (2c, 0.6 mmol). The reaction tube was
evacuated and backfilled with N2 for 3 times. Dry acetone (3 mL) was added with syringe
under N2. The reaction mixture was allowed to stir for 15 min under irradiation of blue LEDs
(5 W). After the reaction was finished, the mixture was concentrated under vacuum to
remove solvent, and the residue was purified by chromatography on silica gel (ethyl acetate:
n-hexane = 1:50) to afford the CF3-substituted cyclic ketones 3.
2-Phenyl-2-(2,2,2-trifluoroethyl)cyclopentanone (3a):
1H NMR (400 MHz, CDCl3) m, 5 H), 2.93 (dd, J = 12.0 Hz, 5.6 Hz, 1 H), 2.80
(dq, J = 15.5 Hz, 11.2 Hz, 1 H), 2.49 (dq, J = 15.5 Hz, 11.2 Hz, 1 H), 2.36-2.16 (m, 2 H),
2.14-1.97 (m,
2
H), 1.86-1.73 (m,
1
H); 13C NMR (100 MHz, CDCl3)
q, J = 276.8 Hz), 53.4, 42.1 (q, J = 27.0 Hz), 35.6,
19
32.5, 18.4; F NMR (376 MHz, CDCl3) t,J = .0 Hz)R (film) 1739 cm-1; ESI-
HRMS: m/z calcd for C13H13F3NaO [M+Na]+ : 265.0816; found 265.0821.
2-(m-Tolyl)-2-(2,2,2-trifluoroethyl)cyclopentanone(3b):
1H NMR (400 MHz, CDCl3) 7.25-7.21 (m, 1 H), 7.18-7.16 (m, 2 H), 7.09-7.07 (m, 1 H),
2.90 (dd, J = 13.4 Hz, 5.8 Hz, 1 H), 2.77 (dq, J = 15.4 Hz, 11.3 Hz, 1 H), 2.49 (dq, J = 15.4
Hz, 11.3 Hz, 1 H), 2.39-2.29 (m, 4 H), 2.25-2.15 (m, 1 H), 2.12-1.95 (m, 2 H), 1.85-1.72 (m,
13
1 H); C NMR (100 MHz, CDCl3) 216.4, 138.7, 136.1, 128.9, 128.5, 127.6, 126.3 (q, J =
Page 11 of 20

19
276.8 Hz), 123.8, 53.4, 42.0 (q, J = 27.3 Hz), 35.6, 32.5, 21.7, 18.4; F NMR (376 MHz,
CDCl3) t,J = .1 Hz)R (film) 1741 cm-1; ESI-HRMS: m/z calcd for
C14H15F3NaO [M+Na]+ : 279.0973; found 279.0971.
2-(3-Fluorophenyl)-2-(2,2,2-trifluoroethyl)cyclopentanone (3c):
1H NMR (400 MHz, CDCl3) m, 1 H), 7.19-7.17 (m, 1 H), 7.14-7.10 (m, 1 H),
7.01-6.96 (m, 1 H), 2.88 (dd, J = 13.2 Hz, 5.6 Hz, 1 H), 2.80 (dq, J = 15.5 Hz, 10.9 Hz, 1 H),
2.45 (dq, J = 15.5 Hz, 10.9 Hz, 1 H), 2.37-2.18 (m, 2 H), 2.15-1.99 (m, 2 H), 1.86-1.73 (m, 1
H); 13C NMR (100 MHz, CDCl3) d, J = 245 Hz), 138.8 (d, J = 6.7 Hz), 130.5
(d, J = 8.6 Hz), 126.2 (q, J = 276.8 Hz), 122.6, 114.9 (d, J = 21.0 Hz), 114.2 (d, J = 21.9 Hz),
53.2, 42.1 (q, J = 27.3 Hz), 35.6, 32.6, 18.4; 19F NMR (376 MHz, CDCl3) t, J = .0
Hz)R (film) 1744 cm-1; ESI-HRMS: m/z calcd for C13H12F4NaO [M+Na]+ :
283.0722; found 283.0727.
2-(p-Tolyl)-2-(2,2,2-trifluoroethyl)cyclopentanone(3d):
1H NMR (400 MHz, CDCl3) 7.28-7.26 (m, 2 H), 7.17-7.15 (m, 2 H), 2.90 (dd, J = 12.0 Hz,
6.0 Hz, 1 H), 2.78 (dq, J = 15.4 Hz, 11.2 Hz, 1 H), 2.52-2.431 (m, 1 H), 2.35-2.26 (m, 4 H),
13
2.24-1.95 (m, 3 H), 1.85-1.74(m, 1H); C NMR (100 MHz, CDCl3) , 137.5, 132.8,
129.6, 126.7, 126.5 (q, J = 276.8 Hz), 53.0, 42.0 (q, J = 27.0 Hz), 35.4, 32.4, 20.1, 18.3; 19F
NMR (376 MHz, CDCl3) t,J = .1 Hz)R (film) 1738 cm-1; ESI-HRMS: m/z
calcd for C14H15F3NaO [M+Na]+ : 279.0973; found 279.0977.
2-(4-Fluorophenyl)-2-(2,2,2-trifluoroethyl)cyclopentanone (3e):
1H NMR (400 MHz, CDCl3) 7.38-7.35 (m, 2 H), 7.07-6.99 (m, 2 H), 2.90 (dd, J = 13.0 Hz,
Page 12 of 20

5.8 Hz, 1 H), 2.79 (dq, J = 15.4 Hz, 11.1 Hz, 1 H), 2.42 (dq, J = 15.4 Hz, 11.1 Hz, 1 H), 2.36-
2.17 (m, 2 H), 2.13-1.98 (m, 2 H), 1.85-1.72 (m, 1 H); 13C NMR (100 MHz, CDCl3) 0,
162.3 (d, J = 246.9 Hz), 131.5, 131.3 (d, J = 9.5 Hz), 128.8 (d, J = 8.5 Hz), 126.3 (q, J =
276.8 Hz), 116.3 (d, J = 21.9 Hz), 116.0 (d, J = 21.0 Hz), 52.8, 42.2 (q, J = 27.3 Hz), 35.5,
32.8, 18.4; 19F NMR (376 MHz, CDCl3) t,J = .2 Hz)R (film) 1741 cm-
1; ESI-HRMS: m/z calcd for C13H12F4NaO [M+Na]+ : 283.0722; found 283.0725.
2-(4-Chlorophenyl)-2-(2,2,2-trifluoroethyl)cyclopentanone (3f):
1H NMR (400 MHz, CDCl3) m, 4 H), 2.89 (dd, J = 13.0 Hz, 5.8 Hz, 1 H), 2.79
(dq, J = 15.6 Hz, 11.0 Hz, 1 H), 2.43 (dq, J = 15.6 Hz, 11.0 Hz, 1 H), 2.37-2.17 (m, 2 H),
2.13-1.99 (m, 2H), 1.85-1.71 (m,
1
H); 13C NMR (100 MHz, CDCl3)
126.2 (q, J = 276.8 Hz), 52.9, 42.1 (q, J = 27.3 Hz), 35.5,
19
32.6, 18.4; F NMR (376 MHz, CDCl3) t,J = .1 Hz)R (film) 1742 cm-1; ESI-
HRMS: m/z calcd for C13H12ClF3NaO [M+Na]+ : 299.0426; found 299.0421.
4-Phenyl-4-(2,2,2-trifluoroethyl)dihydrofuran-3(2H)-one (3g):
1H NMR (400 MHz, CDCl3) m, 2 H), 7.44-7.32 m, 2 H), 7.32-7.28 m, 1 H),
5.06 (d, J = 10.6 Hz, 1 H), 4.22 (d, J = 10.6 Hz, 1 H), 4.11 (d, J = 17.4 Hz, 1 H), 3.92 (d, J =
17.4 Hz, 1 H), 3.04 (dq, J = 15.6 Hz, 10.8 Hz, 1 H), 2.53 (dq, J = 15.6 Hz, 10.8 Hz, 1 H);13C
NMR (100 MHz, CDCl3) q, J= 278.1 Hz), 74.1 (q,
19
J = 2.4 Hz), 69.6, 52.1, 38.9 (q, J = 28.8 Hz); F NMR (376 MHz, CDCl3) t,J =
.0 Hz)R (film) 1766 cm-1; ESI-HRMS: m/z calcd for C12H11F3NaO2 [M+Na]+ : 267.0609;
found 267.0611.
Page 13 of 20

2'-(Trifluoromethyl)-2',3'-dihydrospiro[cyclopentane-1,1'-inden]-2-one (3h):
1H NMR (400 MHz, CDCl3) m, 3 H), 7.07-7.05 (m, 1 H), 3.48-3.41 (m, 1 H),
13
3.26-3.01 (m, 2 H), 2.60-2.37 (m, 4 H), 2.27-2.09 (m, 2 H); C NMR (100 MHz, CDCl3)
216.3 145.2, 141.0, 128.0, 127.6, 126.8 (q, J = 277.1 Hz), 124.9, 122.5, 60.7, 54.3 (q, J =
19
26.7 Hz), 38.4, 37.2, 32.0, 19.9; F NMR (376 MHz, CDCl3) d, J = .0 Hz)R
(film) 1743 cm-1; ESI-HRMS: m/z calcd for C14H13F3NaO [M+Na]+ : 277.0816; found
277.0811.
2'-(Trifluoromethyl)-3',4'-dihydro-2'H-spiro[cyclopentane-1,1'-naphthalen]-2-one (3i):
1H NMR (400 MHz, CDCl3) m, 3 H), 7.00-6.95 (m, 1 H), 3.03-2.93 (m, 1 H),
2.85-2.77 (m, 1 H), 2.75-2.64 (m, 2 H), 2.61-2.48 (m, 2 H), 2.46-2.34 (m, 2 H), 2.19-2.12 (m,
13
2 H), 2.10-2.04 (m, 1 H); C NMR (100 MHz, CDCl3) 218.6, 138.9, 136.3, 129.1, 128.0,
126.8, 126.7, 125.4 (q, J = 280.0 Hz), 52.9, 46.4 (q, J = 24.8 Hz), 41.4, 38.2, 29.8, 27.1, 20.1;
19F NMR (376 MHz, CDCl3) d, J = .7 Hz)R (film) 1744 cm-1; ESI-HRMS: m/z
calcd for C15H15F3NaO [M+Na]+ : 291.0973; found 291.0969.
10-Phenyl-10-(2,2,2-trifluoroethyl)phenanthren-9(10H)-one (5):
1H NMR (400 MHz, CDCl3) 8.19-8.07 (m, 3 H), 7.72-7.66 (m, 1 H), 7.50-7.46 (m, 1 H),
7.43-7.37 (m, 2 H), 7.29-7.15 (m, 4 H), 7.06-7.00 (m, 2 H), 4.17 (dq, J = 15.0 Hz, 10.1 Hz, 1
H), 3.21 (dq, J = 15.0 Hz, 10.1 Hz, 1 H); 13C NMR (100 MHz, CDCl3) 196.8, 141.7, 138.5,
137.1, 135.1, 130.5, 130.3, 129.0, 128.9, 128.8, 128.6, 128.3, 128.1, 127.8, 127.0, 125.7 (q, J
= 277.9 Hz), 124.0, 123.3, 55.1, 42.2 (q, J = 27.3 Hz); 19F NMR (376 MHz, CDCl3)
t, J = .9 Hz)R (film) 1680 cm-1; ESI-HRMS: m/z calcd for C22H15F3NaO
[M+Na]+ : 375.0973; found 375.0975.
Page 14 of 20

4,4,4-Trifluoro-1,2-diphenylbutan-1-one (7):
1H NMR (400 MHz, CDCl3) m, 2 H), 7.53-7.49 (m, 1 H), 7.43-7.39 (m, 2 H),
7.34-7.29 (m, 4 H), 7.27-7.22 (m, 1 H), 4.91 (dd, J = 7.6 Hz, 5.6 Hz, 1 H), 3.38-3.24 (m, 1 H),
2.61-2.49 (m, 1 H); 13C NMR (100 MHz, CDCl3) 196.7, 137.4, 135.7, 133.3, 129.3, 128.8,
128.7, 128.0, 127.8, 125.8 (q, J = 278.5 Hz), 47.1, 37.3 (q, J = 28.0 Hz); 19F NMR (376 MHz,
CDCl3) t, J = .4 Hz)R (film) 1686 cm-1; ESI-HRMS: m/z calcd for
C16H13F3NaO [M+Na]+ : 301.0816; found 301.0814.
Acknowledgement: This research was supported by the Soonchunhyang University
Research Fund and Basic Science Research Program through the National Research
Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning
(2014006224).
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