Novel and efficient approach to (Z)-4-trifluoroethylidene-1,3-dioxolane derivatives via (trifluoromethyl)ethynylation of ketones and aldehydes

Article abstract of DOI:10.1016/j.jfluchem.2008.05.021

Perfluoroalkylated 4-trifluoroethylidene-1,3-dioxolanes 2a-p were prepared in quantitative yields from the reaction of new stable (trifluoromethyl)ethynylation reagent 1a with TBAF at -15 °C for 10 min, followed by treatment with phenyl perfluoroalkylated

Full text of DOI:10.1016/j.jfluchem.2008.05.021

Journal of Fluorine Chemistry 129 (2008) 1018–1028
Contents lists available at ScienceDirect
Journal of Fluorine Chemistry
journal homepage: www.elsevier.com/locate/fluor
Novel and efficient approach to (Z)-4-trifluoroethylidene-1,3-dioxolane
derivatives via (trifluoromethyl)ethynylation of ketones and aldehydes
Sung Lan Jeon a, Ji Hoon Choi a, Jung Ah Cho a, Bum Tae Kim b, In Howa Jeong a,
*
a Department of Chemistry, Yonsei University, Wonju, Republic of Korea
b Korea Research Institute of Chemical Technology, Daejeon, Republic of Korea
A R T I C L E I N F O
A B S T R A C T
Article history:
Perfluoroalkylated 4-trifluoroethylidene-1,3-dioxolanes 2a–p were prepared in quantitative yields from
the reaction of new stable (trifluoromethyl)ethynylation reagent 1a with TBAF at ꢀ15 8C for 10 min,
followed by treatment with phenyl perfluoroalkylated ketones at room temperature. The use of
aldehydes under the same reaction condition afforded 1,3-dioxolanes 2q–r in good yields. The reaction of
1a with TBAF, followed by treatment with aldehydes or ketones at ꢀ15 8C for 10 min and then with
trifluoroacetophenone at room temperature provided 1,3-dioxolane derivatives 2s–t in good yields.
Tetrabutylammonium trifluoropropynylide [II] was treated with benzaldehyde derivatives at ꢀ15 8C for
10 min, followed by treatment with trifluoroacetophenone, to give the corresponding 1,3-dioxolanes 2u–
z and 1,3-dioxines 3u–z with different reaction condition.
Received 31 March 2008
Received in revised form 30 May 2008
Accepted 30 May 2008
Available online 8 June 2008
Keywords:
4-Trifluoroethylidene-1,3-dioxolanes
(Trifluoromethyl)ethynylation
Perfluoroalkylated ketones
Aldehydes
ß 2008 Published by Elsevier B.V.
4-Trifluoroethylidene-4H-1,3-dioxines
TBAF
1. Introduction
2,2-Bis(trifluoromethyl)-4-methylidene as an exocyclic olefin was
synthesized via dehydrobromination of 2,2-bis(trifluoromethyl)-
Fluorinated 1,3-dioxolane compounds have attracted much
attention in recent years because of their unique nonlinear optical,
electrical and chemical properties, which are very important
factors in the development of new optical material. 4-Trifluor-
oethylidene-1,3-dioxolane derivatives are outstanding com-
pounds having nonlinear optical properties [1]. Amorphous
polymers, new Teflon-AF fluorocopolymer, formed from either
polymerization of 2,2-bis(trifluoromethyl)-4,5-difluoro-1,3-diox-
ole monomer [2] or perfluoro(5-methylene-2,2-dimethyl-1,3-
dioxolane) monomer [3] showed better thermal and chemical
stability. Fluorinated dioxolane exocyclic olefins are also a quite
useful intermediate to give the corresponding epoxides, which
furnish as lubricants, curing materials, adhesives and coatings [4].
Several examples have been reported for the synthesis of
fluorinated 1,3-dioxolane, but the methodology for its prepara-
tions is quite limited. Fluorination of 4- or 5-chlorinated 1,3-
dioxolane has been known as a general method for the synthesis of
4- or 5-fluorinated 1,3-dioxolanes [5]. Radical addition reaction of
1,3-dioxolane with perfluoro-1-alkenes in the presence of BPO
also gave 4-fluoroalkylated 1,3-dioxolane in excellent yields [6].
4-bromomethyl-1,3-dioxolane which can be prepared from the
reaction of epibromohydrin with hexafluoroacetone [4]. Reaction
of trifluoropropyne with enol silyl ether generated from aldehyde
in the presence of tetrabutylammoniun fluoride, provided the
corresponding 2,5-disubstituted 4-trifluoroethylidene-1,3-dioxo-
lanes as trifluoromethylated exocyclic olefin [7]. 2-Bromotrifluor-
opropene was reacted with ketones having
a-hydrogen from
carbonyl group in the presence of sodium methoxide to give the
corresponding 2,2,5,5-tetrasubstituted 4-trifluoroethylidene-1,3-
dioxolanes in high yields [1]. Although the reaction mechanisms of
these two reactions are not clear, it seems that the generation of
enolate as an intermediate is a key step to proceed these reactions.
Therefore, aldehydes or ketones having
a-hydrogen carbonyl
group is the key factor for the synthesis of 4-trifluoroethylidene-
1,3-dioxolanes.
Herein, we wish to report a novel and efficient method for the
synthesis of 4-trifluoroethylidene-1,3-dioxolane derivatives via
new stable (trifluoromethyl)ethynylation reagent [8–12] and
mechanistic rationalization for the formation of these compounds.
2. Results and discussion
From previous report that described literature report shows the
reaction of an ethereal solution of trifluoropropynyl lithium with
* Corresponding author. Tel.: +82 33 760 2240; fax: +82 33 763 4323.
E-mail address: jeongih@yonsei.ac.kr (I.H. Jeong).
0022-1139/$ – see front matter ß 2008 Published by Elsevier B.V.
doi:10.1016/j.jfluchem.2008.05.021

S.L. Jeon et al. / Journal of Fluorine Chemistry 129 (2008) 1018–1028
1019
Scheme 1.
Weinreb amide (N-methoxy-N-methylbenzamide), resulted in the
tar formation [13]. By carefully monitoring, it is observed that the
intermediate formed from the reaction of trifluoropropynyl
lithium with Weinreb amide was stable at 0 8C, in which N-
methoxy group in Weinreb benzamide plays an important role in
the formation of lithium complex. Therefore, the trapping reaction
of intermediate with trimethylsilyl chloride at 0 8C, followed by
warming to room temperature afforded trifluoromethylated
propargyl trimethylsilyl ether derivatives 1a–c as new stable
(trifluoromethyl)ethynylation reagents in 70–94% yields (Scheme
1), in which trifluoropropynyl lithium was generated from the
reaction of 2-bromotrifluoropropene with LDA at ꢀ78 8C [14–17].
The reaction of 2-bromotrifluoropropene with LDA results in the
formation of trifluoropropynyl lithium in higher yields with
respect to reactions trifluoropropyne with n-BuLi [18].
In order to examine the ability of 1a–c as (trifluoromethy-
l)ethynylation reagent we carried out the reaction of 1a–c with
reagents as a fluoride source such as tetrabutylammonium fluoride
(TBAF), cesium fluoride, and potassium fluoride in various solvents
at different reaction temperatures, followed by treatment with
2,2,2-trifluoroacetophenone (2 equiv.) to give 4-trifluoroethyli-
dene-1,3-dioxolane derivative 2a (Table 1). It has been found that
the reaction of 1a (1.3 equiv.) with TBAF (1.3 equiv.) in acetonitrile
at ꢀ15 8C for 10 min, followed by reaction with 2,2,2-trifluor-
oacetophenone at room temperature for 1 h, afforded only (Z)-2a
(1:1 diastereomer ratio) in 99% yield, while 1b and 1c provided (Z)-
2a under the same reaction conditions in 90% and 85% yields,
respectively. The use of acetonitrile resulted in better yields as
compared to ether and THF. The use of 1.0 equiv. of 1a in this
reaction also provided the low yield of (Z)-2a. When the reaction of
1a with TBAF was performed at ꢀ35 8C for 10 min, followed by
reaction with 2,2,2-trifluoroacetophenone at room temperature
for 1 h, however, (Z)-2a was obtained in 80% yield.
Intermediate [I] generated from the reaction of 1a with TBAF
[11], was suggested to be an equilibrium with N-methoxy-N-
methylbenzamide and tetrabutylammonium trifluoropropynyl
anion [II] (Scheme 2) which acts as a (trifluoromethyl)ethynylation
reagent to react with 2,2,2-trifluoroacetophenone. N-Methoxy-N-
methylbenzamide, which is a key reagent for the formation of 1
and relatively expensive, was always recovered in quantitative
yield at the end of reaction. In order to compare reactivity between
[II] and trifluoropropynyl lithium against 2,2,2-trifluoroacetophe-
none, we also carried out the direct reaction of 2,2,2-trifluor-
oacetophenone (2 equiv.) with trifluoropropynyl lithium, either
generated from the reaction of 2-bromotrifluoropropene with LDA
at ꢀ78 8C or from the reaction of trifluoropropyne with n-BuLi at
ꢀ78 8C, but desired product (Z)-2a was obtained in only 35% yield.
Thus, tetrabutylammonium, the counter cation of trifluoropropy-
Table 1
Optimization of reaction condition for the preparation of 4-trifluoroethylidene-1,3-dioxolane derivatives 2a
Entry
MF
n
Solvent
t1 (8C)
T1 (min)
t2 (8C)
T2 (h)
Yield (%)a
1
2
TBAF
TBAF
TBAF
TBAF
TBAF
TBAF
TBAF
TBAF
TBAF
TBAF
TBAF
KF
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.3
1.3
1.3
1.3
1.3
Ether
Ether
Ether
Ether
Ether
Ether
Ether
Ether
THF
ꢀ78
ꢀ35
ꢀ15
ꢀ15
ꢀ15
ꢀ15
ꢀ15
ꢀ15
ꢀ15
ꢀ15
ꢀ35
ꢀ15
60
60
60
60
10
10
10
10
10
10
10
10
ꢀ78
ꢀ35
ꢀ15
ꢀ15
ꢀ15
ꢀ15 ! rt
rt
1
1
1
1
1
1
1
1
1
1
1
1
0
0
3
0
4
0
5
0
6
30
79
96
80
99
80
25
7
8
rt
9
rt
10
11
12
CH3CN
CH3CN
DMF
rt
rt
rt
a
Isolated yield.

1020
S.L. Jeon et al. / Journal of Fluorine Chemistry 129 (2008) 1018–1028
Scheme 2.
Scheme 3.
nyl anion, plays an important role for the formation of 2a in
quantitative yield. However, the addition of tetrabutylammonium
chloride in this direct reaction did not provide improved yield
of (Z)-2a.
It seems likely that the reaction mechanism in the formation of
(Z)-2a involves the addition of intermediate [II] toward 2,2,2-
trifluoroacetophenone to give an intermediate [III], which further
reacts with another equivalence of 2,2,2-trifluoroacetophenone to
afford an intermediate [IV] that undergoes diagonal exocyclization
to give vinyl carbanion intermediate [V]. Protonation of inter-
mediate [V] provided two diastereomers (syn:anti = 1:1). (Z)-
Stereospecificity of 2a can be rationalized by the less steric
hindrance between vinylic trifluoromethyl group and groups on
the allylic position in the formation of intermediate [V]. The
plausible mechanism was described in Scheme 3.
The assignment of syn and anti diastereomers of (Z)-2a was
confirmed by the comparison of X-ray diffraction of 2e, whose both
diastereomers can be crystallized, with 19F NMR spectrum. The X-
ray data [19] of two diastereomers of 2e (Figs. 1 and 2) showed that
the vinylic trifluoromethyl group is arranged to O-3 position of 1,3-
dioxolane ring system and two phenyl rings are arranged on the
same side in the syn isomer and on the opposite side in the anti
isomer. It has been found that 19F NMR signal (ꢀ58.62 ppm) in the
syn isomer of (Z)-2e is more shielded than anti (ꢀ58.46 ppm).
The reactions of 1a with 2,2,2-trifluoroacetophenone or
pentafluoroethyl phenyl ketone derivatives having proton, chloro,
fluoro, methoxy, trifluoromethyl, vinyl, and phenoxy substitution
on the benzene rings afforded (Z)-2a–o in 97–99% yields.
However, the longer reaction time was required in reaction of
Fig. 1. ORTEP representation of anti-(Z)-2e at the 50% probability level. Selected bond
˚
lengths (A) and angles (8): C1–C2 1.318(2), C1–C7 1.479(3), C1–H1A 0.9300, C2–O3
1.3606(19), C2–C6 1.523(2), O3–C4 1.4172(19), C4–O5 1.405(2), C4–C11 1.515(2),
C4–C19 1.548(3), O5–C6 1.4317(18), C6–C23 1.542(2), C6–C31 1.544(3); C2–C1–C7
123.38(17), C2–C1–H1A 118.3, C7–C1–H1A 118.3, C1–C2–O3 119.99(16), C1–C2–C6
131.65(16), O3–C2–C6 108.20(13), C2–O3–C4 109.93(13), O5–C4–O3 106.29(12),
O5–C4–C11 112.67(14),O3–C4–C11109.90(14), O5–C4–C19 109.88(15),O3–C4–C19
105.15(15), C11–C4–C19 112.50(14), C4–O5–C6 110.91(12), O5–C6–C2 102.38(12),
O5–C6–C23 108.76(13), C2–C6–C23 119.47(14), O5–C6–C31 103.27(13), C23–C6–
C31 111.66(14), C2–C6–C31 109.67(15).

S.L. Jeon et al. / Journal of Fluorine Chemistry 129 (2008) 1018–1028
1021
heterocyclic moieties such as a thiophene also reacted with
tetrabutylammonium trifluoropropynylide [II] to give the corre-
sponding dioxolane (Z)-2p in 98% yield. When 1a was reacted with
TBAF, followed by reaction with 1,1,1-trifluoroacetone under
the same reaction condition, however, several products were
obtained which could not be identified. The treatment of
tetrabutylammonium trifluoropropynylide [II] with 2 equiv.
aldehydes such as butanal, 2-methylbutanal and cyclohexancar-
baldehyde resulted in the formation of the corresponding 4-
trifluoroethylidene-1,3-dioxolane derivatives (Z)-2q–r in 72–74%
yields, while the reaction with 2 equiv. of ketones did not provide
any desired products. The experimental results of these reactions
are summarized in Table 2.
Treatment of tetrabutylammonium trifluoropropynylide [II]
with 1 equiv. of butanal or cyclohexanone, followed by 1 equiv. of
trifluoroacetophenone, resulted in the formation of the corre-
sponding 4-trifluoroethylidene-1,3-dioxolane derivatives 2s and
2t in 72% and 82% yields, respectively (Scheme 4).
Fig. 2. ORTEP representation of syn-(Z)-2e at the 50% probability level. Selected
˚
bond lengths (A) and angles (8): C1–C2 1.313(6), C1–C7 1.459(6), C1–H1A 0.9300,
However, tetrabutylammonium trifluoropropynylide [II] was
treated with 1 equiv. of benzaldehyde derivatives at ꢀ15 8C for
10 min, followed by 1 equiv. of trifluoroacetophenone, to give the
corresponding 1,3-dioxolane derivatives 2u–z and 1,3-dioxine
derivatives 3u–z depending on the reaction conditions. Generally,
the high temperature and prolong reaction time resulted in the
formation of 3 as a single product. The experimental results of
these reactions are summarized in Table 3.
C2–O3 1.363(5), C2–C6 1.521(5), O3–C4 1.413(4), C4–O5 1.420(4), C4–C11
1.516(5), C4–C19 1.539(6), O5–C6 1.445(5), C6–C23 1.520(5), C6–C31 1.544(5);
C2–C1–C7 123.8(4), C2–C1–H1A 118.1, C7–C1–H1A 118.1, C1–C2–O3 122.7(3), C1–
C2–C6 128.5(4), O3–C2–C6 108.7(3), C2–O3–C4 110.5(3), O5–C4–O3 106.6(3), O5–
C4–C11 114.4(3), O3–C4–C11 114.7(3), O5–C4–C19 106.6(3), O3–C4–C19 106.6(3),
C11–C4–C19 110.3(3), C4–O5–C6 110.6(3), O5–C6–C2 102.4(3), O5–C6–C23
111.2(3), C2–C6–C23 116.5(3), O5–C6–C31 104.7(3), C23–C6–C31 113.4(3), C2–
C6–C31 107.4(3).
Formation of 3 can be rationalized by the rearrangement of the
carbanion intermediate [V] to [VI] which undergoes endo-diagonal
cyclization to produce the six-membered ring intermediate. 1,3-H
shift, followed by protonation afforded the dioxine derivatives 3.
The driving force to produce the intermediate [VI] is due to the
resonance stabilization of the carbanion by phenyl group and
relatively high stability of 1,3-dioxine system as compare to
ethylidene-1,3-dioxolane system. Comparison of entries 8, 10, 12
1a with ketone derivatives having chloro, fluoro, 2-methoxy and
trifluoromethyl substitution on the benzene ring. Although we did
not carry out the reaction with the longer perfluroalkylated
ketone than pentafluoroethylated one, the similar results could be
obtained because the steric effect does not affect on the addition
reaction of tetrabutylammonium trifluoropropynylide [II] toward
perfluoroalkylated ketone. Trifluoromethylated ketones having
Table 2
Preparation of 4-trifluoroethylidene-1,3-dioxolane derivatives 2
Compound
R1
R2
t (h)
Yield (%)a,b
2a
2b
2c
2d
2e
2f
CF3
C6H5
1
2
99
98
97
99
99
98
98
97
99
99
99
97
98
97
98
98
72c
74c
CF3
4-F–C6H4
CF3
4-Cl–C6H4
4-CH3O–C6H4
2-CH3O–C6H4
4-CF3–C6H4
3-CF3–C6H4
4-CH2 CH–C6H4
4-C6H5O–C6H4
C6H5
2
CF3
1
CF3
3
CF3
5
2g
2h
2i
CF3
5
CF3
1
CF3
1
2j
C2F5
C2F5
C2F5
C2F5
C2F5
C2F5
CF3
1
2k
2l
4-CH3O–C6H4
4-CF3–C6H4
4-Cl–C6H4
4-CH2 CH–C6H4
4-C6H5O–C6H4
2-Thienyl
1
12
2
2m
2n
2o
2p
2q
2r
1
1
1
C3H7
c-Hex
H
1
H
2
a
Isolated yield.
b
c
All products were obtained as a 1:1 diastereomer mixture.
Reaction of 2nd step was performed at ꢀ20 8C, followed by warming to room temperature.

1022
S.L. Jeon et al. / Journal of Fluorine Chemistry 129 (2008) 1018–1028
Scheme 4.
Table 3
Preparation of 2,5-bis(trifluoromethyl)-1,3-dioxine derivatives 3
Entry
X
Y
Condition 1
Condition 2
Compound
Yield (%)a
2
3
1
2
H
H
ꢀ15 8C, 10 min
ꢀ15 8C, 10 min
ꢀ15 8C, 10 min
ꢀ15 8C, 10 min
ꢀ15 8C, 10 min
ꢀ15 8C, 10 min
ꢀ15 8C, 10 min
ꢀ15 8C, 10 min
ꢀ15 8C, 10 min
ꢀ15 8C, 10 min
ꢀ15 8C, 10 min
ꢀ15 8C, 10 min
ꢀ15 8C, 10 min
2u, 3u
2u, 3u
2v, 3v
2v, 3v
2w, 3w
2w, 3w
2x, 3x
2x, 3x
2y, 3y
2y, 3y
2z, 3z
2z, 3z
42
0
18
65
20
65
12
67
0
H
H
ꢀ15 8C ! rt, 30 min
ꢀ15 8C, 10 min
3
H
OCH3
OCH3
CF3
CF3
H
43
0
4
H
ꢀ15 8C ! rt, 30 min
ꢀ15 8C, 10 min
5
H
51
0
6
H
ꢀ15 8C ! rt, 30 min
ꢀ15 8C ! rt, 30 min
ꢀ15 8C ! rt, 12 h
ꢀ15 8C ! 0 8C, 30 min
ꢀ15 8C ! rt, 3 h
7
OCH3
OCH3
F
29
0
8
H
28
0
9
H
51
0
10
11
12
F
H
51
24
55
CF3
CF3
H
ꢀ15 8C, 10 min
32
0
H
ꢀ15 8C ! rt, 30 min
a
Isolated yield.
Scheme 5.
in Table 3 would support the mechanistic consideration as shown
in Scheme 5. Thus, the final 1,3-H shift should be facilitated by the
electron-withdrawing substituent on the aromatic ring and the
electron-releasing group should work in an opposite manner.
trifluoroethylidene-1,3-dioxolane derivatives in good to excellent
yields. Several stable and isolable (trifluoromethyl)ethynylation
reagents were successfully prepared from the reaction of Weinreb
amides with trifluoropropynyl lithium formed from 2-bromotri-
fluoropropene. Tetrabutylammonium trifluoropropynylide [II],
from the reaction of (trifluoromethyl)ethynylation reagents with
TBAF, was reacted with 1 equiv. of benzaldehyde derivatives at
ꢀ15 8C for 10 min, followed by treatment with 1 equiv. of
trifluoroacetophenone, to give the corresponding 1,3-dioxolane
and 1,3-dioxine derivatives depending on the reaction condition.
3. Conclusions
In this paper, we have explored the (trifluoromethyl)ethynyla-
tion to perfluoroalkylated phenyl ketones and aldehydes with a
wide range of substituents to produce the corresponding 4-

S.L. Jeon et al. / Journal of Fluorine Chemistry 129 (2008) 1018–1028
1023
Generally, the prolong reaction time at relatively high temperature
afforded the corresponding 1,3-dioxine derivatives.
(s, 3H), 0.23 (s, 9H); 19F NMR (CDCl3, internal standard CFCl3)
d
ꢀ51.19 (s, 3F); MS, m/z (relative intensity) 269 (M+, 3), 176 (10), 89
(7), 83 (39), 70 (37), 69 (48), 43 (100); IR (neat) 2960, 2275,1281,
1150, 1040 cmꢀ1. Anal. Calcd. for C10H18F3NO2Si: C, 44.59; H, 6.74.
Found: C, 44.45; H, 6.77.
4. Experimental
1H NMR spectra were recorded on a 200-MHz Gemini-200 NMR
spectrometer and 19F NMR spectra were recorded on a 100-MHz
Bruker AC-100F NMR spectrometer with tetramethylsilane (TMS)
and CFCl3 as an internal standard, respectively and the upfield as
4.2. General procedure for the preparation of 4-trifluoroethylidene-
1,3-dioxolanes 2
negative. All chemical shifts (
d
) are expressed in parts per million
A 25-mL two-neck round bottom flask equipped with a
magnetic stirrer bar, a septum and condenser connected to an
argon source was charged with 5 mL of CH3CN and 1a (0.430 g,
1.3 mmol) and then cooled to ꢀ15 8C. After TBAF (1.3 mmol, 1.0 M
in THF) was added and stirred at ꢀ15 8C for 10 min, perfluor-
oalkylated ketone (2.0 mmol) was added and then the reaction
mixture was allowed to warm to room temperature. The reaction
mixture was extracted with ether twice, dried over anhydrous
MgSO4 and chromatographed on SiO2 column. Elution with a
mixture of hexane and ether (9:1) provided 4-trifluoroethylidene-
1,3-dioxolanes 2.
and coupling constant (J) are given in Hertz. Infrared spectra were
determined on a Mattson Genesis series FT High Resolution
Spectrophotometer. Mass spectra were obtained by using GC/MS-
Qp1000-Shimadzu (EI, 70 eV). Melting points were determined in
open capillary tubes and are uncorrected.
Commercially available reagents were purchased from Aldrich,
Lancaster, Tokyo Kasei and Fluorochem. All solvents were dried by
general purification method. Flash chromatography was per-
formed on 40–60
mm silica gel (230–400 mesh).
4.1. General procedure for the preparation of
(trifluoromethyl)ethynylation reagents 1
4.2.1. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(trifluoromethyl)-2,4-
diphenyl-1,3-dioxolane (2a)
A 100-mL three-neck round bottom flask equipped with a
magnetic stirrer bar, a septum and condenser connected to an
argon source was charged with 50 mL of THF and 2-bromo-3,3,3-
trifluoropropene (6.25 mmol) and then cooled to ꢀ78 8C. After LDA
(12.5 mmol) was added and stirred at ꢀ78 8C for 0.5 h, Weinreb
amide (3.125 mmol) was added and then the reaction mixture was
allowed to warm to 0 8C, followed by quench with TMSCl
(3.2 mmol). The reaction mixture was allowed to warm to room
temperature, extracted with ether twice, dried over anhydrous
MgSO4 and chromatographed on SiO2 column. Elution with a
mixture of hexane and ether (19:1) provided (trifluoromethy-
l)ethynylation reagents 1a–c.
2a (anti:syn = 1:1) was prepared in 99% yield (0.438 g)
according to the general procedure (trifluoroacetophenone was
used as a perfluoroalkylated ketone). 2a (syn): mp 64–65 8C; 1H
NMR (CDCl3)
d
7.70–7.66 (m, 4H), 7.52–7.48 (m, 6H), 5.40 (q,
ꢀ58.64
J = 7.1 Hz, 1H); 19F NMR (CDCl3, internal standard CFCl3)
d
(d, J = 7.1 Hz, 3F), ꢀ77.17 (s, 3F), ꢀ82.51 (s, 3F); MS, m/z (relative
intensity) 442 (M+, 1), 373 (32), 199 (13), 171 (10), 151 (29), 105
(100), 77 (12); IR (KBr) 3136, 3078, 2937, 1709, 1500, 1454, 1279,
1207, 1132, 1063, 731, 698 cmꢀ1. Anal. Calcd. for C19H11F9O2: C,
51.60; H, 2.51. Found: C, 51.44; H, 2.47%. 2a (anti): oil; 1H NMR
(CDCl3)
(CDCl3, internal standard CFCl3)
d
7.52–7.17 (m, 10H), 5.43 (q, J = 7.1 Hz, 1H); 19F NMR
d
ꢀ58.53 (d, J = 7.1 Hz, 3F), ꢀ76.84
(s, 3F), ꢀ83.18 (s, 3F). Anal. Calcd. for C19H11F9O2: C, 51.60; H, 2.51.
4.1.1. 4,4,4-Trifluoro-1-(N-methoxy-N-methylamino)-1-phenyl-1-
(trimethylsiloxyl)-2-butyne (1a)
Found: C, 51.48; H, 2.49%.
1a was prepared in 94% yield (0.972 g) according to the general
procedure (N-methoxy-N-methylbenzamide was used as a Wein-
4.2.2. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(trifluoromethyl)-2,4-
bis(p-fluorophenyl)-1,3-dioxolane (2b)
2b (anti:syn = 1:1) was prepared in 98% yield (0.468 g)
according to the general procedure (trifluoromethyl p-fluorophe-
nyl ketone was used as a perfluoroalkylated ketone). 2a (syn): oil;
reb amide). 1a: oil; 1H NMR (CDCl3)
d
7.65–7.60 (m, 2H), 7.38–7.35
(m, 3H), 3.46 (s, 3H), 2.40 (s, 3H), 0.20 (s, 9H); 19F NMR (CDCl3,
internal standard CFCl3)
d
ꢀ51.20 (s, 3F); MS, m/z (relative
intensity) 331 (M+, 5), 271 (100), 242 (36), 208 (12), 179 (11), 151
(23), 105 (27), 77 (10), 73 (47); IR (neat) 3067, 2960, 2262,1273,
1147, 1087 cmꢀ1. Anal. Calcd. for C15H20F3NO2Si: C, 54.36; H, 6.08.
Found: C, 54.08; H, 6.01.
1H NMR (CDCl3)
J = 6.9 Hz, 1H); 19F NMR (CDCl3, internal standard CFCl3)
(d, J = 6.9 Hz, 3F), ꢀ77.30 (s, 3F), ꢀ82.68 (s, 3F), ꢀ109.67 (s, 1F),
ꢀ110.48 (s, 1F); MS, m/z (relative intensity) 478 (M+, 1), 409 (30),
258 (33), 217 (22), 189 (25), 169 (17), 123 (100), 95 (20), 75 (8); IR
(neat) 3118, 2924, 1715, 1611, 1372, 1290, 1206, 1083, 842 cmꢀ1
.
d 7.72–7.63 (m, 4H), 7.25–7.02 (m, 4H), 5.38 (q,
d
ꢀ58.69
4.1.2. 4,4,4-Trifluoro-1-(N-methoxy-N-methylamino)-1-benzyl-1-
(trimethylsiloxyl)-2-butyne (1b)
1b was prepared in 65% yield (0.701 g) according to the general
procedure (N-methoxy-N-methylphenylacetamide was used as a
Anal. Calcd. for C19H9F11O2: C, 47.72; H, 1.90. Found: C, 47.65; H,
1.85%. 2a (anti): mp 54–55 8C; 1H NMR (CDCl3)
7.49–7.40 (m, 4H),
7.04–6.90 (m, 4H), 5.43 (q, J = 7.1 Hz, 1H); 19F NMR (CDCl3, internal
standard CFCl3)
d
Weinreb amide). 1b: oil; 1H NMR (CDCl3)
d
7.36–7.32 (m, 5H), 3.66
(s, 3H), 3.12 (s, 2H), 2.41 (s, 3H), 0.21 (s, 9H); 19F NMR (CDCl3,
internal standard CFCl3)
d
ꢀ58.63 (d, J = 7.1 Hz, 3F), ꢀ77.00 (s, 3F), ꢀ83.37
(s, 3F), ꢀ109.37 (s, 1F), ꢀ110.05 (s, 1F). Anal. Calcd. for C19H9F11O2:
d
ꢀ51.47 (s, 3F); MS, m/z (relative
C, 47.72; H, 1.90. Found: C, 47.59; H, 1.84%.
intensity) 345 (M+, 3), 285 (11), 254 (21), 151 (18), 134 (16), 91
(44), 77 (11), 73 (100), 65 (16), 45 (51); IR (neat) 3050, 2960,
2271,1275, 1147, 1099 cmꢀ1. Anal. Calcd. for C16H22F3NO2Si: C,
55.63; H, 6.42. Found: C, 55.39; H, 6.31.
4.2.3. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(p-chlorophenyl)-2,4-
bis(trifluoromethyl)-1,3-dioxolane (2c)
2c (anti:syn = 1:1) was prepared in 97% yield (0.496 g)
according to the general procedure (p-chlorophenyl trifluoro-
methyl ketone was used as a perfluoroalkylated ketone). 2c (syn):
4.1.3. 4,4,4-Trifluoro-1-(N-methoxy-N-methylamino)-1-methyl-1-
(trimethylsiloxyl)-2-butyne (1c)
oil; 1H NMR (CDCl3)
d F
7.65–7.22 (m, 8H), 5.45 (q, J = 6.9 Hz, 1H); 19
1c was prepared in 70% yield (0.588 g) according to the general
procedure (N-methoxy-N-methylacetamide was used as a Wein-
NMR (CDCl3, internal standard CFCl3)
d
ꢀ58.66 (d, J = 6.9 Hz, 3F),
ꢀ76.93 (s, 3F), ꢀ83.26 (s, 3F); MS, m/z (relative intensity) 512
reb amide). 1c: oil; 1H NMR (CDCl3)
d
3.60 (s, 3H), 2.60 (s, 3H), 1.64
(M++2, 2), 510 (M+, 4), 441 (24), 274 (28), 205 (12), 139 (100), 111

1024
S.L. Jeon et al. / Journal of Fluorine Chemistry 129 (2008) 1018–1028
(25), 75 (14), 69 (4); IR (neat) 3124, 2929, 1711, 1600, 1369, 1281,
1137, 1096, 839 cmꢀ1. Anal. Calcd. for C19H9Cl2F9O2: C, 44.64; H,
omethylphenyl ketone was used as a perfluoroalkylated ketone).
2g (syn): oil; 1H NMR (CDCl3)
7.97–7.39 (m, 8H), 5.53 (q,
J = 7.1 Hz, 1H); 19F NMR (CDCl3, internal standard CFCl3)
ꢀ58.73
d
1.77. Found: C, 44.32; H, 1.83%. 2c (anti): oil; 1H NMR (CDCl3)
d
d
7.65–7.22 (m, 8H), 5.38 (q, J = 6.9 Hz, 1H); 19F NMR (CDCl3, internal
standard CFCl3)
(d, J = 7.1 Hz, 3F), ꢀ63.66 (s, 3F), 63.78 (s, 3F), ꢀ76.76 (s, 3F),
ꢀ83.09 (s, 3F); MS, m/z (relative intensity) 578 (M+, 1), 461 (8), 308
(10), 267 (18), 239 (24), 219 (45), 173 (100), 145 (95), 126 (36), 95
(21), 75 (23); IR (neat) 3084, 2964, 1713, 1621, 1369, 1267, 1136,
1094, 1076, 875, 775, 690 cmꢀ1. Anal. Calcd. for C21H9F15O2: C,
43.62; H, 1.57. Found: C, 43.35; H, 1.53%. 2g (anti): oil; 1H NMR
d
ꢀ58.63 (d, J = 6.9 Hz, 3F), ꢀ77.25 (s, 3F), ꢀ82.59
(s, 3F). Anal. Calcd. for C19H9Cl2F9O2: C, 44.64; H, 1.77. Found: C,
44.37; H, 1.82%.
4.2.4. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(trifluoromethyl)-2,4-
bis(p-methoxyphenyl)-1,3-dioxolane (2d)
2d (anti:syn = 1:1) was prepared in 99% yield (0.497 g) according
to the general procedure (trifluoromethyl p-methoxyphenyl ketone
was used as a perfluoroalkylated ketone). 2d (syn): mp 69–70 8C; 1H
(CDCl3)
(CDCl3, internal standard CFCl3)
(s, 6F), ꢀ77.19 (s, 3F), ꢀ82.49 (s, 3F). Anal. Calcd. for C21H9F15O2: C,
d
7.65–7.22 (m, 8H), 5.46 (q, J = 7.1 Hz, 1H); 19F NMR
d
ꢀ58.73 (d, J = 7.1 Hz, 3F), ꢀ63.45
43.62; H, 1.57. Found: C, 43.41; H, 1.56%.
NMR (CDCl3)
J = 7.1 Hz, 1H), 3.85 (s, 6H); 19F NMR (CDCl3, internal standard
CFCl3)
m/z (relative intensity) 502 (M+, 15), 433 (13), 270 (64), 201 (23),
135 (100), 84 (18), 77 (19); IR (KBr) 3124, 2964, 1710, 1614, 1370,
1260, 1177, 1079, 837 cmꢀ1. Anal. Calcd. for C21H15F9O4: C, 50.21;
d 7.64–7.57 (m, 4H), 7.04–6.95 (m, 4H), 5.33 (q,
4.2.8. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(trifluoromethyl)-2,4-
bis(p-vinylphenyl)-1,3-dioxolane (2h)
2h (anti:syn = 1:1) was prepared in 97% yield (0.479 g)
according to the general procedure (trifluoromethyl p-vinylphenyl
ketone was used as a perfluoroalkylated ketone). 2h (syn): oil; 1H
d
ꢀ58.56 (d, J = 7.1 Hz, 3F), ꢀ77.17 (s, 3F), ꢀ82.70 (s, 3F); MS,
H, 3.01. Found: C, 49.85; H, 2.94%. 2d (anti): oil; 1H NMR (CDCl3)
7.40–7.33 (m, 4H), 6.80–6.71 (m, 4H), 5.36 (q, J = 7.1 Hz, 1H), 3.88 (s,
3H), 3.85 (s, 3H); 19F NMR (CDCl3, internal standard CFCl3)
ꢀ58.48
(d, J = 7.1 Hz, 3F), ꢀ77.05 (s, 3F), ꢀ83.42 (s, 3F). Anal. Calcd. for
21H15F9O4: C, 50.21; H, 3.01. Found: C, 49.91; H, 2.97%.
d
NMR (CDCl3)
5.85 (d, J = 17.7 Hz, 2H), 5.44–5.26 (m, 3H); 19F NMR (CDCl3,
internal standard CFCl3)
ꢀ82.48 (s, 3F); MS, m/z (relative intensity) 494 (M+, 11), 425 (18),
266 (37), 197 (12), 177 (18), 131 (100), 103 (31), 77 (25); IR (neat)
3074, 2988, 1707, 1611, 1369, 1202, 1125, 1094, 839 cmꢀ1. Anal.
Calcd. for C23H15F9O2: C, 55.88; H, 3.06. Found: C, 55.45; H, 3.00%.
d 7.68–7.43 (m, 8H), 6.75 (dd, J = 17.7, 11.0 Hz, 2H),
d
d
ꢀ58.63 (d, J = 6.5 Hz, 3F), ꢀ77.09 (s, 3F),
C
4.2.5. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(trifluoromethyl)-2,4-
bis(o-methoxyphenyl)-1,3-dioxolane (2e)
2h (anti): oil; 1H NMR (CDCl3)
2H), 5.73 (dd, J = 17.5, 5.3 Hz, 2H), 5.42 (d, J = 7.1 Hz, 1H), 5.31 (dd,
J = 13.6, 2.8 Hz, 2H); 19F NMR (CDCl3, internal standard CFCl3)
d 7.49–7.24 (m, 8H), 6.70–6.53 (m,
2e (anti:syn = 1:1) was prepared in 99% yield (0.497 g)
according to the general procedure (trifluoromethyl o-methox-
yphenyl ketone was used as a perfluoroalkylated ketone). 2e (syn):
d
ꢀ58.57 (d, J = 7.1 Hz, 3F), ꢀ76.81 (s, 3F), ꢀ83.14 (s, 3F). Anal. Calcd.
mp 112–113 8C; 1H NMR (CDCl3)
d
7.85–7.81 (m, 1H), 7.66–7.62
for C23H15F9O2: C, 55.88; H, 3.06. Found: C, 55.53; H, 3.01%.
(m, 1H), 7.49–7.41 (m, 2H), 7.12–6.99 (m, 4H), 5.80 (q, J = 7.5 Hz,
1H), 3.88 (s, 3H), 3.87 (s, 3H); 19F NMR (CDCl3, internal standard
4.2.9. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(trifluoromethyl)-2,4-
bis(p-phenoxyphenyl)-1,3-dioxolane (2i)
CFCl3)
d
ꢀ58.62 (d, J = 7.5 Hz, 3F), ꢀ75.29 (s, 3F), ꢀ81.14 (s, 3F); MS,
m/z (relative intensity) 502 (M+, 8), 433 (22), 270 (9), 201 (5), 135
(100), 84 (7), 77 (19); IR (KBr) 3014, 2948, 1708, 1603, 1360, 1261,
1128, 1068, 756 cmꢀ1. Anal. Calcd. for C21H15F9O4: C, 50.21; H,
3.01. Found: C, 49.98; H, 2.98%. 2e (anti): mp 110–111 8C; 1H NMR
2i (anti:syn = 1:1) was prepared in 99% yield (0.620 g)
according to the general procedure (trifluoromethyl p-phenox-
yphenyl ketone was used as a perfluoroalkylated ketone). 2i
(syn): oil; 1H NMR (CDCl3)
1H); 19F NMR (CDCl3, internal standard CFCl3)
d
d
7.65–6.80 (m, 18H), 5.38 (q, J = 7.1 Hz,
ꢀ58.57 (d,
(CDCl3)
5.31 (q, J = 7.5 Hz, 1H), 3.88 (s, 3H), 3.39 (s, 3H); 19F NMR (CDCl3,
internal standard CFCl3)
d
7.68–7.64 (m, 1H), 7.41–7.24 (m, 3H), 6.96–6.72 (m, 4H),
J = 7.1 Hz, 3F), ꢀ76.88 (s, 3F), ꢀ83.23 (s, 3F); MS, m/z (relative
intensity) 626 (M+, 17), 557 (4), 239 (8), 197 (100), 169 (10), 141
(18), 115 (15), 77 (30); IR (neat) 3067, 2927, 1710, 1613, 1371,
1247, 1133, 1087, 842 cmꢀ1. Anal. Calcd. for C31H19F9O4: C, 59.43;
d
ꢀ58.56 (d, J = 7.5 Hz, 3F), ꢀ74.35 (s, 3F),
ꢀ81.61 (s, 3F). Anal. Calcd. for C21H15F9O4: C, 50.21; H, 3.01. Found:
C, 49.94; H, 2.96%.
H, 3.06. Found: C, 59.11; H, 3.01%. 2i (anti): oil; 1H NMR (CDCl3)
7.65–6.80 (m, 18H), 5.38 (q, J = 7.1 Hz, 1H); 19F NMR (CDCl3,
internal standard CFCl3)
d
4.2.6. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(trifluoromethyl)-2,4-
bis(p-trifluoromethylphenyl)-1,3-dioxolane (2f)
2f (anti:syn = 1:1) was prepared in 98% yield (0.566 g)
according to the general procedure (trifluoromethyl p-trifluor-
omethylphenyl ketone was used as a perfluoroalkylated ketone). 2f
d
ꢀ58.50 (d, J = 7.1 Hz, 3F), ꢀ77.09 (s, 3F),
ꢀ82.55 (s, 3F). Anal. Calcd. for C31H19F9O4: C, 59.43; H, 3.06. Found:
C, 59.04; H, 2.99%.
(syn): oil; 1H NMR (CDCl3)
1H); 19F NMR (CDCl3, internal standard CFCl3)
d
7.88–7.76 (m, 8H), 5.47 (q, J = 6.0 Hz,
4.2.10. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(pentafluoroethyl)-
2,4-diphenyl-1,3-dioxolane (2j)
2j (anti:syn = 2:1) was prepared in 99% yield (0.537 g)
according to the general procedure (pentafluoroethyl phenyl
ketone was used as a perfluoroalkylated ketone). 2j (syn): oil;
d
ꢀ58.77 (d,
J = 6.9 Hz, 3F), ꢀ63.45 (s, 3F), ꢀ63.55 (s, 3F), ꢀ77.14 (s, 3F), ꢀ82.42
(s, 3F); MS, m/z (relative intensity) 578 (M+, 2), 509 (23), 308 (12),
267 (21), 219 (17), 173 (100), 145 (11); IR (neat) 3078, 2952, 1713,
1624, 1328, 1208, 1136, 1089, 837 cmꢀ1
.
Anal. Calcd. for
1H NMR (CDCl3)
J = 6.9 Hz, 1H); 19F NMR (CDCl3, internal standard CFCl3)
d 7.68–7.62 (m, 4H), 7.56–7.40 (m, 6H), 5.55 (q,
C
21H9F15O2: C, 43.62; H, 1.57. Found: C, 43.39; H, 1.61%. 2f (anti):
d
ꢀ58.78
oil; 1H NMR (CDCl3)
d
7.68–7.53 (m, 8H), 5.55 (q, J = 6.9 Hz, 1H); 19
F
(d, J = 6.9 Hz, 3F), ꢀ78.25 (s, 3F), ꢀ79.79 (s, 3F), ꢀ118.21 (d,
J = 279.6 Hz, 1F), ꢀ120.17 (d, J = 279.6 Hz, 1F), ꢀ126.02 (s, 1F),
ꢀ126.16 (s, 1F); MS, m/z (relative intensity) 542 (M+, 1), 423 (19),
299 (3), 199 (3), 151 (10), 105 (100), 77 (27); IR (neat) 3079, 1708,
NMR (CDCl3, internal standard CFCl3)
d
ꢀ58.77 (d, J = 6.9 Hz, 3F),
ꢀ63.78 (s, 3F), ꢀ63.80 (s, 3F), ꢀ76.61 (s, 3F), ꢀ82.97 (s, 3F). Anal.
Calcd. for C21H9F15O2: C, 43.62; H, 1.57. Found: C, 43.24; H, 1.52%.
1455, 1275, 1199, 1052, 755, 698 cmꢀ1
. Anal. Calcd. for
4.2.7. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(trifluoromethyl)-2,4-
bis(m-trifluoromethylphenyl)-1,3-dioxolane (2g)
2g (anti:syn = 1:1) was prepared in 98% yield (0.566 g)
according to the general procedure (trifluoromethyl m-trifluor-
C
21H11F13O2: C, 46.51; H, 2.04. Found: C, 46.24; H, 2.08%. 2j
(anti): oil; 1H NMR (CDCl3)
d
7.50–7.09 (m, 10H), 5.57 (q, J = 7.1 Hz,
ꢀ58.74 (d,
J = 7.1 Hz, 3F), ꢀ78.44 (s, 3F), ꢀ79.88 (s, 3F), ꢀ119.11 to ꢀ120.02
1H); 19F NMR (CDCl3, internal standard CFCl3)
d

S.L. Jeon et al. / Journal of Fluorine Chemistry 129 (2008) 1018–1028
1025
(m, 2F), ꢀ126.57 to ꢀ126.66 (m, 2F). Anal. Calcd. for C21H11F13O2:
nyl ketone was used as a perfluoroalkylated ketone). 2n (syn): oil;
1H NMR (CDCl3)
7.66–7.47 (m, 8H), 6.75 (dd, J = 17.6, 11.0 Hz,
2H), 5.85 (d, J = 17.6 Hz, 2H), 5.53 (q, J = 6.9 Hz, 1H), 5.37 (d,
J = 11.0 Hz, 2H); 19F NMR (CDCl3, internal standard CFCl3)
(d, J = 6.9 Hz, 3F), ꢀ78.17 (s, 3F), ꢀ79.71 (s, 3F), ꢀ118.24 (d,
J = 279.5 Hz, 1F), ꢀ120.79 (d, J = 279.5 Hz, 1F), ꢀ125.91 to ꢀ126.06
(m, 2F); MS, m/z (relative intensity) 594 (M+, 3), 475 (15), 337 (2),
177 (6), 131 (100), 103 (15), 77 (10); IR (neat) 3094, 2987, 1708,
1613, 1282, 1195, 1085, 837 cmꢀ1. Anal. Calcd. for C25H15F13O2: C,
50.52; H, 2.54. Found: C, 50.27; H, 2.49%. 2n (anti): oil; 1H NMR
C, 46.51; H, 2.04. Found: C, 46.19; H, 2.09%.
d
4.2.11. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(pentafluoroethyl)-
2,4-bis(p-methoxyphenyl)-1,3-dioxolane (2k)
2k (anti:syn = 1:1) was prepared in 99% yield (0.596 g)
according to the general procedure (pentafluoroethyl p-methox-
yphenyl ketone was used as a perfluoroalkylated ketone). 2k (syn):
d
ꢀ58.77
oil; 1H NMR (CDCl3)
d
7.62–7.52 (m, 4H), 7.03–6.93 (m, 4H), 5.48 (q,
J = 7.1 Hz, 1H), 3.85 (s, 6H); 19F NMR (CDCl3, internal standard
CFCl3)
d
ꢀ58.70 (d, J = 7.1 Hz, 3F), ꢀ78.19 (s, 3F), ꢀ79.77 (s, 3F),
(CDCl3)
5.56 (q, J = 6.9 Hz, 1H), 5.23–5.33 (m, 2H); 19F NMR (CDCl3, internal
standard CFCl3)
d 7.60–7.16 (m, 8H), 6.70–6.50 (m, 2H), 5.79–5.64 (m, 2H),
ꢀ117.03 (d, J = 279.3 Hz, 1F), ꢀ122.16 (d, J = 279.3 Hz, 1F), ꢀ125.98
(s, 1F), ꢀ126.16 (s, 1F); MS, m/z (relative intensity) 602 (M+, 1), 483
(6), 320 (3), 229 (3), 201 (11), 181 (7), 135 (100), 92 (16), 77 (16); IR
d
ꢀ58.64 (d, J = 6.9 Hz, 3F), ꢀ78.44 (s, 3F), ꢀ79.82
(s, 3F), ꢀ119.23 to ꢀ119.88 (m, 2F), ꢀ126.53 to 126.66 (m, 2F).
Anal. Calcd. for C25H15F13O2: C, 50.52; H, 2.54. Found: C, 50.21; H,
2.48%.
(neat) 3010, 2963, 1707, 1613, 1342, 1260, 1179, 1083, 839 cmꢀ1
.
Anal. Calcd. for C23H15F13O4: C, 45.86; H, 2.52. Found: C, 45.61; H,
2.47%. 2k (anti): oil; 1H NMR (CDCl3)
7.41–7.27 (m, 4H), 6.81–
6.64 (m, 4H), 5.50 (q, J = 7.1 Hz, 1H), 3.76 (s, 3H), 3.72 (s, 3H); 19
NMR (CDCl3, internal standard CFCl3)
d
F
4.2.15. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(pentafluoroethyl)-
2,4-bis(p-phenoxyphenyl)-1,3-dioxolane (2o)
2o (anti:syn = 1:1) was prepared in 98% yield (0.711 g)
according to the general procedure (pentafluoroethyl p-phenox-
yphenyl ketone was used as a perfluoroalkylated ketone). 2o (syn):
d
ꢀ58.58 (d, J = 7.1 Hz, 3F),
ꢀ78.41 (s, 3F), ꢀ79.87 (s, 3F), ꢀ119.34 to ꢀ119.59 (m, 1F), ꢀ119.98
(s, 1F), ꢀ126.60 (s, 2F). Anal. Calcd. for C23H15F13O4: C, 45.86; H,
2.52. Found: C, 45.52; H, 2.45%.
oil; 1H NMR (CDCl3)
NMR (CDCl3, internal standard CFCl3)
ꢀ78.11 to ꢀ78.28 (m, 3F), ꢀ79.68 to ꢀ79.79 (m, 3F), ꢀ116.07 to
ꢀ123.02 (m, 2F), ꢀ125.91 to ꢀ126.38 (m, 2F); MS, m/z (relative
intensity) 726 (M+, 12), 607 (8), 469 (1), 382 (3), 304 (2), 244 (3),
197 (100), 141 (5), 77 (5); IR (neat) 3064, 2969, 1707, 1612, 1366,
1223, 1134, 1084, 840 cmꢀ1. Anal. Calcd. for C33H19F13O4: C, 54.56;
d
7.63–6.75 (m, 18H), 5.56–5.45 (m, 1H); 19
ꢀ58.60 to ꢀ58.76 (m, 3F),
F
4.2.12. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(pentafluoroethyl)-
2,4-bis(p-trifluoromethylphenyl)-1,3-dioxolane (2l)
2l (anti:syn = 1:1) was prepared in 97% yield (0.658 g)
according to the general procedure (pentafluoroethyl p-trifluor-
omethylphenyl ketone was used as a perfluoroalkylated ketone). 2l
d
(syn): oil; 1H NMR (CDCl3)
1H); 19F NMR (CDCl3, internal standard CFCl3)
d
7.87–7.73 (m, 8H), 5.60 (q, J = 6.9 Hz,
ꢀ58.92 (d,
d
H, 2.64. Found: C, 54.20; H, 2.57%. 2o (anti): oil; 1H NMR (CDCl3)
7.63–6.75 (m, 18H), 5.56–5.45 (m, 1H); 19F NMR (CDCl3, internal
standard CFCl3)
d
J = 6.9 Hz, 3F), ꢀ63.94 (s, 3F), ꢀ78.33 (s, 3F), ꢀ79.76 (s, 3F),
ꢀ118.52 (d, J = 281.1 Hz, 1F), ꢀ119.56 (d, J = 281.1 Hz, 1F), ꢀ126.95
(s, 1F), 127.03 (s, 3F); MS, m/z (relative intensity) 678 (M+, 1), 659
(1), 560 (1), 371 (9), 219 (32), 173 (90), 145 (100), 126 (35), 69 (35);
IR (neat) 3137, 2959, 1710, 1624, 1326, 1226, 1138, 1072,
839 cmꢀ1. Anal. Calcd. for C23H9F19O2: C, 40.73; H, 1.34. Found:
d
ꢀ58.60 to ꢀ58.76 (m, 3F), ꢀ78.11 to ꢀ78.28 (m,
3F), ꢀ79.68 to ꢀ79.79 (m, 3F), ꢀ116.07 to ꢀ123.02 (m, 2F),
ꢀ125.91 to ꢀ126.38 (m, 2F). Anal. Calcd. for C33H19F13O4: C, 54.56;
H, 2.64. Found: C, 54.24; H, 2.58%.
C, 40.29; H, 1.30%. 2l (anti): oil; 1H NMR (CDCl3)
8H), 5.65 (q, J = 6.9 Hz, 1H); 19F NMR (CDCl3, internal standard
CFCl3)
d
7.85–7.36 (m,
4.2.16. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(trifluoromethyl)-
2,4-dithiophen-2-yl-1,3-dioxolane (2p)
2p (anti:syn = 1:1) was prepared in 98% yield (0.445 g)
according to the general procedure (trifluoromethyl 2-thiophenyl
ketone was used as a perfluoroalkylated ketone). 2p (syn): oil; 1H
d
ꢀ58.81 (d, J = 6.9 Hz, 3F), ꢀ63.94 (s, 6F), ꢀ78.33 (s, 3F),
ꢀ79.76 (s, 3F), ꢀ119.07 to ꢀ119.93 (m, 2F), ꢀ126.40 (s, 2F). Anal.
Calcd. for C23H9F19O2: C, 40.73; H, 1.34. Found: C, 40.34; H, 1.29%.
NMR (CDCl3)
2H), 5.37 (q, J = 7.1 Hz, 1H); 19F NMR (CDCl3, internal standard
CFCl3)
m/z (relative intensity) 454 (M+, 8), 274 (36), 255 (9), 246 (100),
205 (16), 177 (53), 132 (12), 111 (63), 83 (28), 69 (11); IR (neat)
3119, 2962, 1714, 1372, 1275, 1137, 1069 cmꢀ1. Anal. Calcd. for
d 7.54–7.49 (m, 2H), 7.44–7.40 (m, 2H), 7.14–7.09 (m,
4.2.13. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(p-chlorophenyl)-
2,4-bis(pentafluoroethyl)-1,3-dioxolane (2m)
2m (anti:syn = 1:1) was prepared in 98% yield (0.600 g)
according to the general procedure (pentafluoroethyl p-chlorophe-
nyl ketone was used as a perfluoroalkylated ketone). 2m (syn): oil;
d
ꢀ58.88 (d, J = 7.1 Hz, 3F), ꢀ77.78 (s, 3F), ꢀ82.70 (s, 3F); MS,
1H NMR (CDCl3)
NMR (CDCl3, internal standard CFCl3)
ꢀ78.12 (s, 3F), ꢀ79.66 (s, 3F), ꢀ118.38 (d, J = 280.5 Hz, 1F), ꢀ120.76
(d, J = 280.5 Hz, 1F), ꢀ126.97 to ꢀ127.08 (m, 2F); MS, m/z (relative
intensity) 611 (M+, 1), 491 (22), 333 (4), 187 (4), 158 (7), 141 (26),
139 (100), 111 (5); IR (neat) 3077, 1708, 1602, 1281, 1197, 1083,
841 cmꢀ1. Anal. Calcd. for C21H9Cl2F13O2: C, 41.22; H, 1.48. Found:
d
7.64–7.42 (m, 8H), 5.52 (q, J = 6.9 Hz, 1H); 19F
ꢀ58.86 (d, J = 6.9 Hz, 3F),
C
15H7F9O2S2: C, 39.66; H, 1.55. Found: C, 39.39; H, 1.52%. 2p (anti):
oil; 1H NMR (CDCl3)
7.36–7.33 (m, 2H), 7.20–7.16 (m, 2H), 6.95–
6.89 (m, 2H), 5.38 (q, J = 7.1 Hz, 1H); 19F NMR (CDCl3, internal
standard CFCl3)
d
d
d
ꢀ58.78 (d, J = 7.1 Hz, 3F), ꢀ77.63 (s, 3F), ꢀ83.13
(s, 3F). Anal. Calcd. for C15H7F9O2S2: C, 39.66; H, 1.55. Found: C,
39.35; H, 1.51%.
C, 40.93; H, 1.44%. 2m (anti): oil; 1H NMR (CDCl3)
8H), 5.56 (q, J = 6.9 Hz, 1H); 19F NMR (CDCl3, internal standard
CFCl3)
d
7.63–7.15 (m,
4.2.17. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-dipropyl-1,3-dioxolane
(2q)
2q (anti:syn = 1:1) was prepared in 72% yield (0.171 g)
according to the general procedure (butanal was used as a
carbonyl compound). 2q (syn): oil; 1H NMR (CDCl3)
d 5.30 (t,
d
ꢀ58.75 (d, J = 6.9 Hz, 3F), ꢀ78.38 (s, 3F), ꢀ79.79 (s, 3F),
ꢀ119.17 to ꢀ120.70 (m, 2F), ꢀ126.60 to ꢀ126.70 (m, 2F). Anal.
Calcd. for C21H9Cl2F13O2: C, 41.22; H, 1.48. Found: C, 40.88; H, 1.42%.
J = 4.7 Hz, 1H), 4.57–4.44 (m, 1H), 4.48 (q, J = 7.7 Hz, 1H), 1.85–1.43
(m, 4H), 0.97 (t, J = 7.3 Hz, 3H); 19F NMR (CDCl3, internal standard
4.2.14. (Z)-5-(2,2,2-Trifluoroethylidene)-2,4-bis(trifluoromethyl)-
2,4-bis(p-vinylphenyl)-1,3-
CFCl3)
d
ꢀ57.28 (d, J = 7.7 Hz, 3F); MS, m/z (relative intensity) 238
dioxolane (2n)
(M+, 1), 210 (7), 195 (35), 149 (37), 127 (33), 109 (34), 91 (40), 55
(100); IR (neat) 2965, 1703, 1395, 1252, 1110 cmꢀ1. Anal. Calcd. for
2n (anti:syn = 1:1) was prepared in 97% yield (0.576 g)
according to the general procedure (pentafluoroethyl p-vinylphe-
C11H17F3O2: C, 55.45; H, 7.19. Found: C, 55.03; H, 7.03%. 2q (anti):

1026
S.L. Jeon et al. / Journal of Fluorine Chemistry 129 (2008) 1018–1028
oil; 1H NMR (CDCl3)
4.51 (q, J = 7.5 Hz, 1H), 1.85–1.43 (m, 4H), 0.97 (t, J = 7.3 Hz, 3H);
19F NMR (CDCl3, internal standard CFCl3)
3F). Anal. Calcd. for C11H17F3O2: C, 55.45; H, 7.19. Found: C, 55.09;
H, 7.07%.
d
5.52 (t, J = 4.7 Hz, 1H), 4.69–4.66 (m, 1H),
internal standard CFCl3)
d
ꢀ58.24 (d, J = 6.9 Hz, 3F), ꢀ82.84 (s, 3F);
MS, m/z (relative intensity) 374 (M+, 6), 305 (28), 100 (35), 172
(100), 131 (37), 105 (60), 77 (74), 51 (36); IR (neat) 3079, 2915,
1714, 1500, 1454, 1266, 1197, 1136, 1081, 755, 698 cmꢀ1. Anal.
Calcd. for C18H12F6O2: C, 57.76; H, 3.23. Found: C, 57.41; H, 3.16%.
d
ꢀ57.27 (d, J = 7.5 Hz,
2u (anti): oil; 1H NMR (CDCl3)
4.48 (q, J = 7.1 Hz, 1H); 19F NMR (CDCl3, internal standard CFCl3)
ꢀ58.21 (d, J = 7.1 Hz, 3F), ꢀ82.37 (s, 3F). Anal. Calcd. for
18H12F6O2: C, 57.76; H, 3.23. Found: C, 57.38; H, 3.14%.
d 7.72–7.39 (m, 10H), 5.99 (s, 1H),
4.2.18. (Z)-5-(2,2,2-trifluoroethylidene)-2,4-dicyclohexyl-1,3-
dioxolane (2r)
2r (anti:syn = 1:1) was prepared in 74% yield (0.235 g)
according to the general procedure (cyclohexylcarbaldehyde
was used as a carbonyl compound). 2r (syn): oil; 1H NMR (CDCl3)
d
C
4.2.22. (Z)-5-(2,2,2-Trifluoroethylidene)-2-trifluoromethyl-2-
(p-methoxyphenyl)-4-phenyl-1,3-dioxolane (2v)
d
5.27 (d, J = 4.5 Hz, 1H), 4.50 (q, J = 7.7 Hz, 1H), 4.44–4.42 (m, 1H),
1.76–1.05 (m, 22H); 19F NMR (CDCl3, internal standard CFCl3)
d
2v (anti:syn = 1:1) was prepared in 43% yield (0.174 g)
according to the general procedure (benzaldehyde and trifluor-
omethyl p-methoxyphenyl ketone were used as carbonyl com-
pounds and condition 2 is ꢀ15 8C for 10 min). 2v (syn): oil; 1H NMR
ꢀ57.18 (d, J = 7.7 Hz, 3F); MS, m/z (relative intensity) 318 (M+, 1),
235 (60), 207 (27), 189 (100), 147 (16), 111 (9), 95 (43), 81 (31), 67
(12); IR (neat) 2930, 1701, 1322, 1284, 1110 cmꢀ1. Anal. Calcd. for
C
17H25F3O2: C, 64.13; H, 7.91. Found: C, 63.88; H, 7.79%. 2r (anti):
oil; 1H NMR (CDCl3)
5.03 (d, J = 4.1 Hz, 1H), 4.49 (q, J = 7.7 Hz, 1H),
4.38–4.37 (m, 1H), 1.76–1.05 (m, 22H); 19F NMR (CDCl3, internal
standard CFCl3)
ꢀ57.09 (d, J = 7.7 Hz, 3F). Anal. Calcd. for
17H25F3O2: C, 64.13; H, 7.91. Found: C, 63.85; H, 7.80%.
(CDCl3) d 7.92–6.90 (m, 9H), 5.49–5.45(m, 1H), 4.49 (q, J = 7.5 Hz,
d
1H), 3.84 (s, 3H); 19F NMR (CDCl3, internal standard CFCl3)
d
ꢀ58.19 (d, J = 7.5 Hz, 3F), ꢀ83.03 (s, 3F); MS, m/z (relative
intensity) 404 (M+, 12), 335 (54), 172 (83), 135 (100), 107 (12),
77 (34); IR (neat) 3014, 2941, 1708, 1602, 1310, 1268, 1170, 1077,
835, 755, 698 cmꢀ1. Anal. Calcd. for C19H14F6O3: C, 56.44; H, 3.49.
d
C
4.2.19. (Z)-5-(2,2,2-Trifluoroethylidene)-2-trifluoromethyl-2-
phenyl-4-propyl-1,3-dioxolane (2s)
2s (anti:syn = 1:1) was prepared in 72% yield (0.245 g)
according to the general procedure (butanal and trifluoroaceto-
phenone were used as a carbonyl compound). 2s (syn): oil; 1H NMR
Found: C, 56.23; H, 3.46%. 2v (anti): oil; 1H NMR (CDCl3)
6.92 (m, 9H), 5.97 (s, 1H), 4.46 (q, J = 7.3 Hz, 1H), 3.85 (s, 3H); 19
NMR (CDCl3, internal standard CFCl3)
d 7.67–
F
d
ꢀ58.17 (d, J = 7.3 Hz, 3F),
ꢀ82.54 (s, 3F). Anal. Calcd. for C19H14F6O3: C, 56.44; H, 3.49. Found:
C, 56.19; H, 3.44%.
(CDCl3)
J = 7.5 Hz, 1H), 1.86–1.42 (m, 4H), 0.93 (t, J = 7.3 Hz, 3H); 19F NMR
(CDCl3, internal standard CFCl3)
(s, 3F); MS, m/z (relative intensity) 340 (M+, 1), 271 (31), 229 (7),
149 (9), 123 (10), 105 (100), 91 (20), 77 (33); IR (neat) 3069, 2967,
1716, 1291, 1218, 1119, 1088, 1048, 755, 698 cmꢀ1. Anal. Calcd. for
d 7.65–7.58 (m, 2H), 7.54–7.38 (m, 3H), 5.10 (s, 1H), 4.71 (q,
4.2.23. (Z)-5-(2,2,2-Trifluoroethylidene)-2-trifluoromethyl-2-(p-
trifluoromethylphenyl)-4-phenyl-1,3-dioxolane (2w)
d
ꢀ57.92 (d, J = 7.5 Hz, 3F), ꢀ82.82
2w (anti:syn = 1:1) was prepared in 51% yield (0.225 g)
according to the general procedure (benzaldehyde and trifluor-
omethyl p-trifluoromethylphenyl ketone were used as carbonyl
compounds and condition 2 is ꢀ15 8C for 10 min). 2w (syn): oil; 1H
C
15H14F6O2: C, 52.95; H, 4.15. Found: C, 52.51; H, 4.07%. 2s (anti):
oil; 1H NMR (CDCl3)
7.65–7.58 (m, 2H), 7.54–7.38 (m, 3H), 4.77–
4.61 (m, 2H), 1.85–1.42 (m, 4H), 1.01 (t, J = 7.3 Hz, 3H); 19F NMR
(CDCl3, internal standard CFCl3)
d
NMR (CDCl3) d 7.87–7.18 (m, 9H), 6.02 (s, 1H), 4.53 (q, J = 7.5 Hz,
1H); 19F NMR (CDCl3, internal standard CFCl3)
d
ꢀ58.34 (d,
d
ꢀ57.90 (d, J = 7.5 Hz, 3F), ꢀ83.30
J = 7.5 Hz, 3F), ꢀ63.54 (s, 3F), ꢀ82.36 (s, 3F); MS, m/z (relative
intensity) 442 (M+, 5), 373 (17), 200 (42), 181 (9), 172 (100), 145
(31), 131 (36), 103 (17), 77 (18); IR (neat) 3071, 2930, 1716, 1264,
1132, 1072, 837, 753, 695 cmꢀ1. Anal. Calcd. for C19H11F9O3: C,
51.60; H, 2.51. Found: C, 51.32; H, 2.42%. 2w (anti): oil; 1H NMR
(s, 3F). Anal. Calcd. for C15H14F6O2: C, 52.95; H, 4.15. Found: C,
52.48; H, 4.06%.
4.2.20. (Z)-5-(2,2,2-Trifluoroethylidene)-2-trifluoromethyl-2-
phenyl-1,3-dioxaspiro[4,5]decane (2t)
2t (anti:syn = 1:1) was prepared in 82% yield (0.300 g)
according to the general procedure (cyclohexanone and trifluor-
oacetophenone were used as a carbonyl compound). 2t (syn): oil;
(CDCl3)
1H); 19F NMR (CDCl3, internal standard CFCl3)
J = 7.5 Hz, 3F), ꢀ63.54 (s, 3F), ꢀ82.75 (s, 3F). Anal. Calcd. for
19H11F9O3: C, 51.60; H, 2.51. Found: C, 51.37; H, 2.44%.
d
7.87–7.18 (m, 9H), 5.50–5.47 (m, 1H), 4.46 (q, J = 7.5 Hz,
d
ꢀ58.30 (d,
C
1H NMR (CDCl3)
d
7.69–7.64 (m, 2H), 7.44–7.40 (m, 3H), 4.65 (q,
J = 7.5 Hz, 1H), 2.13–2.07 (m, 1H), 1.86–1.23 (m, 9H); 19F NMR
(CDCl3, internal standard CFCl3)
4.2.24. (Z)-5-(2,2,2-Trifluoroethylidene)-2-trifluoromethyl-4-(p-
methoxyphenyl)-2-phenyl-1,3-dioxolane (2x)
d
ꢀ57.69 (d, J = 7.5 Hz, 3F), ꢀ84.08
(s, 3F); MS, m/z (relative intensity) 366 (M+, 3), 297 (56), 192 (14),
175 (20), 123 (21), 105 (100), 91 (17), 81 (64), 67 (27); IR (neat)
3067, 2944, 1708, 1374, 1257, 1194, 1084, 751, 696 cmꢀ1. Anal.
Calcd. for C17H16F6O2: C, 55.74; H, 4.40. Found: C, 55.32; H, 4.28%.
2x (anti:syn = 1:1) was prepared in 29% yield (0.117 g)
according to the general procedure (p-methoxybenzaldehyde
and trifluoroacetophenone were used as carbonyl compounds
and condition 2 is ꢀ15 8C to room temperature). 2x (syn): oil; 1H
2t (anti): oil; 1H NMR (CDCl3)
3H), 4.60 (q, J = 7.5, 1H), 2.15–2.09 (m, 1H), 1.88–1.25 (m, 9H); 19
NMR (CDCl3, internal standard CFCl3)
d
7.69–7.64 (m, 2H), 7.44–7.40 (m,
NMR (CDCl3) d 7.76–7.66 (m, 2H), 7.50–7.42 (m, 3H), 7.38–7.29
F
(m, 2H), 7.00–6.95 (m, 2H), 5.45–5.42 (m, 1H), 4.40 (q, J = 7.5 Hz,
1H), 3.85 (s, 3H); 19F NMR (CDCl3, internal standard CFCl3)
d
ꢀ58.18 (d, J = 7.5 Hz, 3F), ꢀ82.94 (s, 3F); MS, m/z (relative
intensity) 404 (M+, 27), 335 (1), 230 (7), 202 (100), 187 (13), 133
(8), 105 (22), 77 (17); IR (neat) 3069, 2961, 1714, 1614, 1353,
1256, 1178, 1075, 839, 754, 696 cmꢀ1
. Anal. Calcd. for
d
ꢀ57.64 (d, J = 7.5 Hz, 3F),
ꢀ84.48 (s, 3F). Anal. Calcd. for C17H16F6O2: C, 55.74; H, 4.40. Found:
C, 55.41; H, 4.30%.
4.2.21. (Z)-5-(2,2,2-Trifluoroethylidene)-2-trifluoromethyl-2,4-
diphenyl-1,3-dioxolane (2u)
C
19H14F6O3: C, 56.44; H, 3.49. Found: C, 56.15; H, 3.38%. 2x
2u (anti:syn = 1:1) was prepared in 42% yield (0.157 g)
according to the general procedure (benzaldehyde and trifluor-
oacetophenone were used as carbonyl compounds and condition 2
(anti): oil; 1H NMR (CDCl3)
d
7.71–7.69 (m, 2H), 7.60–7.41 (m,
3H), 7.19–7.11 (m, 2H), 5.96 (s, 1H), 4.47 (q, J = 7.5 Hz, 1H), 3.80
(s, 3H); 19F NMR (CDCl3, internal standard CFCl3)
d
ꢀ58.15 (d,
is ꢀ15 8C for 10 min). 2u (syn): oil; 1H NMR (CDCl3)
d
7.72–7.42 (m,
J = 7.5 Hz, 3F), ꢀ82.31 (s, 3F). Anal. Calcd. for C19H14F6O3: C,
10H), 5.48–5.47(m, 1H), 4.41 (q, J = 6.9 Hz, 1H); 19F NMR (CDCl3,
56.44; H, 3.49. Found: C, 56.11; H, 3.41%.

S.L. Jeon et al. / Journal of Fluorine Chemistry 129 (2008) 1018–1028
1027
4.2.25. (Z)-5-(2,2,2-Trifluoroethylidene)-2-trifluoromethyl-4-
4.3.2. 2,5-Bis(trifluoromethyl)-2-(p-methoxyphenyl)-6-phenyl-4H-
1,3-dioxine (3v)
(fluorophenyl)-2-phenyl-1,3-dioxolane (2y)
2y (anti:syn = 1:1) was prepared in 51% yield (0.200 g)
according to the general procedure (fluorobenzaldehyde and
trifluoroacetophenone were used as carbonyl compounds
3v was prepared in 65% yield (0.263 g) according to the general
procedure (benzaldehyde and trifluoromethyl p-methoxyphenyl
ketone were used as carbonyl compounds and condition 2 is
and condition 2 is ꢀ15 to 0 8C). 2y (syn): oil; 1H NMR (CDCl3)
d
ꢀ15 8C to room temperature). 3v: oil; 1H NMR (CDCl3)
d 7.65–6.89
7.69–7.65 (m, 2H), 7.57–7.38 (m, 3H), 7.29–7.01 (m, 4H), 5.98 (s,
1H), 4.47 (q, J = 7.3 Hz, 1H); 19F NMR (CDCl3, internal standard
(m, 9H), 3.83 (s, 3H), 3.32 (q, J = 9.6 Hz, 2H); 19F NMR (CDCl3,
internal standard CFCl3)
d
ꢀ65.02 (t, J = 9.6 Hz, 3F), ꢀ85.07 (s, 3F);
CFCl3)
d
ꢀ58.23 (d, J = 7.3 Hz, 3F), ꢀ82.45 (s, 3F), ꢀ110.75 to ꢀ11.37
MS, m/z (relative intensity) 404 (M+, 11), 335 (83), 270 (14), 201
(m, 1F); MS, m/z (relative intensity) 392 (M+, 10), 323 (31),
(9), 172 (27), 135 (100), 107 (22), 92 (20), 77 (52); IR (neat) 3064,
2963, 1711, 1613, 1373, 1260, 1136, 1083, 840, 755, 697 cmꢀ1
.
Anal. Calcd. for C19H14F6O3: C, 56.44; H, 3.49. Found: C, 56.03; H,
3.41%.
218 (32), 190 (100), 149 (12), 105 (35), 77 (20); IR (neat) 3071,
2926, 1714, 1608, 1373, 1264, 1123, 1053, 840, 753, 695 cmꢀ1
.
Anal. Calcd. for C18H11F7O2: C, 55.11; H, 2.83. Found: C, 54.83;
H, 2.77%. 2y (anti): oil; 1H NMR (CDCl3)
7.69–7.65 (m, 2H), 7.56–
7.38 (m, 3H), 7.29–7.01 (m, 4H), 5.48–5.45 (m, 1H), 4.39
(q, J = 7.3 Hz, 1H); 19F NMR (CDCl3, internal standard CFCl3)
d
4.3.3. 2,5-Bis(trifluoromethyl)-2-(p-trifluoromethylphenyl)-6-
phenyl-4H-1,3-dioxine (3w)
d
ꢀ58.20 (d, J = 7.3 Hz, 3F), ꢀ82.90 (s, 3F), ꢀ110.75 to ꢀ111.37 (m,
1F). Anal. Calcd. for C18H11F7O2: C, 55.11; H, 2.83. Found: C, 54.87;
H, 2.78%.
3w was prepared in 67% yield (0.296 g) according to the general
procedure (benzaldehyde and trifluoromethyl p-trifluoromethyl-
phenyl ketone were used as carbonyl compounds and condition 2
is ꢀ15 8C to room temperature). 3w: oil; 1H NMR (CDCl3)
d 7.87–
4.2.26. (Z)-5-(2,2,2-Trifluoroethylidene)-2-trifluoromethyl-4-(p-
trifluoromethylphenyl)-2-phenyl-1,3-dioxolane (2z)
2z (anti:syn = 1:1) was prepared in 32% yield (0.141 g)
according to the general procedure (trifluoromethylbenzalde-
hyde and trifluoroacetophenone were used as carbonyl com-
pounds and condition 2 is ꢀ15 8C for 10 min. 2z (syn): oil; 1H
7.83 (m, 2H), 7.77–7.70 (m, 2H), 7.52–7.35 (m, 5H), 3.34 (q,
J = 9.6 Hz, 2H); 19F NMR (CDCl3, internal standard CFCl3)
d
ꢀ63.51
(s, 3F), ꢀ64.94 (q, J = 9.6 Hz, 3F), ꢀ84.81 (s, 3F); MS, m/z (relative
intensity) 442 (M+, 22), 423 (8), 373 (85), 289 (8), 173 (100), 145
(51), 108 (29), 77 (43); IR (neat) 3066, 2941, 1714, 1499, 1326,
1266, 1197, 1137, 1089, 843, 755, 695 cmꢀ1. Anal. Calcd. for
NMR (CDCl3)
d
7.82–7.39 (m, 9H), 7.16 (s, 1H), 4.62–4.40 (m, 1H);
C19H11F9O2: C, 51.60; H, 2.51. Found: C, 51.37; H, 2.44%.
19F NMR (CDCl3, internal standard CFCl3)
d
ꢀ58.35 (d, J = 7.3 Hz,
3F), ꢀ63.38 (s, 3F), ꢀ82.50 to ꢀ82.20 (m, 3F); MS, m/z (relative
intensity) 442 (M+, 10), 373 (26), 240 (55), 199 (31), 173 (92), 145
(100), 127 (39), 105 (77), 77 (86); IR (neat) 3067, 2929, 1713,
1620, 1327, 1266, 1171, 1071, 842, 755, 692 cmꢀ1. Anal. Calcd.
for C19H11F9O2: C, 51.60; H, 2.51. Found: C, 51.27; H, 2.45%. 2z
(anti): oil; 1H NMR (CDCl3)
1H), 4.62–4.40 (m, 1H); 19F NMR (CDCl3, internal standard CFCl3)
4.3.4. 2,5-Bis(trifluoromethyl)-6-(p-methoxyphenyl)-2-phenyl-4H-
1,3-dioxine (3x)
3x was prepared in 28% yield (0.113 g) according to the general
procedure (p-methoxybenzaldehyde and trifluoroacetophenone
were used as carbonyl compounds and condition 2 is ꢀ15 8C to
d
7.82–7.39 (m, 9H), 5.55–5.53 (m,
room temperature for 12 h). 3x: oil; 1H NMR (CDCl3)
d 7.73–6.83
(m, 9H), 3.83 (s, 3H), 3.29 (dq, J = 9.8, 2.0 Hz, 2H); 19F NMR (CDCl3,
internal standard CFCl3)
d
ꢀ58.31 (d, J = 7.5 Hz, 3F), ꢀ63.35 (s, 3F), ꢀ82.44 to ꢀ82.01 (m,
d
ꢀ65.05 (t, J = 9.8 Hz, 3F), ꢀ84.95 (s, 3F);
3F). Anal. Calcd. for C19H11F9O2: C, 51.60; H, 2.51. Found: C, 51.31;
H, 2.46%.
MS, m/z (relative intensity) 404 (M+, 60), 373 (23), 335 (54), 240
(13), 202 (100), 167 (11), 105 (81), 77 (28); IR (neat) 3067, 2939,
1712, 1373, 1256, 1137, 1087, 841, 749, 696 cmꢀ1. Anal. Calcd. for
4.3. General procedure for the preparation of 4-trifluoroethylidene-
C19H14F6O3: C, 56.44; H, 3.49. Found: C, 56.23; H, 3.46%.
4H-1,3-dioxines 3
4.3.5. 2,5-Bis(trifluoromethyl)-6-(p-fluorophenyl)-2-phenyl-4H-1,3-
dioxine (3y)
A 25-mL two-neck round bottom flask equipped with a
magnetic stirrer bar, a septum and condenser connected to an
argon source was charged with 5 mL of CH3CN and 1a (0.430 g,
1.3 mmol) and then cooled to ꢀ15 8C. After TBAF (1.3 mmol, 1.0 M
in THF) was added and stirred at ꢀ15 8C for 10 min, perfluor-
oalkylated ketone (2.0 mmol) was added and then the reaction
mixture was allowed to warm to room temperature. The reaction
mixture was extracted with ether twice, dried over anhydrous
MgSO4 and chromatographed on SiO2 column. Elution with a
mixture of hexane and ether (9:1) provided 4-trifluoroethylidene-
4H-1,3-dioxines 3.
3y was prepared in 51% yield (0.200 g) according to the general
procedure (p-fluorobenzaldehyde and trifluoroacetophenone were
used as carbonyl compounds and condition 2 is ꢀ15 8C to room
temperature for 3 h). 3y: oil; 1H NMR (CDCl3)
d 7.86–7.67 (m, 2H),
7.56–7.42 (m, 3H), 7.38–7.01 (m, 4H), 3.29 (dq, J = 9.7, 2.4 Hz, 2H);
19F NMR (CDCl3, internal standard CFCl3)
d
ꢀ64.97 (t, J = 9.7 Hz, 3F),
ꢀ85.01 (s, 3F), ꢀ111.18 to ꢀ111.37 (m, 1F); MS, m/z (relative
intensity) 392 (M+, 20), 373 (30), 323 (64), 240 (16), 190 (88), 105
(100), 77 (37); IR (neat) 3068, 2931, 1712, 1372, 1266, 1137, 1087,
843, 752, 694 cmꢀ1. Anal. Calcd. for C18H11F7O2: C, 55.11; H, 2.83.
Found: C, 54.83; H, 2.77%.
4.3.1. 2,5-Bis(trifluoromethyl)-2,6-diphenyl-4H-1,3-dioxine (3u)
3u was prepared in 65% yield (0.243 g) according to the general
procedure (benzaldehyde and trifluoroacetophenone were used as
4.3.6. 2,5-Bis(trifluoromethyl)-6-(p-trifluoromethylphenyl)-2-
phenyl-4H-1,3-dioxine (3z)
carbonyl compounds and condition
temperature). 3u: oil; 1H NMR (CDCl3)
7.51–7.34 (m, 8H), 3.33 (dq, J = 9.6, 4.2 Hz, 2H); 19F NMR (CDCl3,
internal standard CFCl3)
MS, m/z (relative intensity) 374 (M+, 53), 305 (100), 221 (7), 165
(9), 105 (18), 77 (42); IR (neat) 3067, 2939, 1711, 1603, 1375, 1227,
1137, 1032, 754, 698 cmꢀ1. Anal. Calcd. for C18H12F6O2: C, 57.76; H,
3.23. Found: C, 57.38; H, 3.15%.
2
is ꢀ15 8C to room
3z was prepared in 55% yield (0.200 g) according to the general
procedure (p-trifluoromethylbenzaldehyde and trifluoroacetophe-
none were used as carbonyl compounds and condition 2 is ꢀ15 8C
d
7.72–7.69 (m, 2H),
d
ꢀ64.92 (t, J = 9.6 Hz, 3F), ꢀ84.97 (s, 3F);
to room temperature). 3z: oil; 1H NMR (CDCl3)
d 7.77–7.18 (m, 9H),
3.37 (dq, J = 9.6, 2.2 Hz, 2H); 19F NMR (CDCl3, internal standard
CFCl3)
d
ꢀ63.70 (s, 3F), ꢀ64.68 (t, J = 9.6 Hz, 3F), ꢀ85.00 (s, 3F); MS,
m/z (relative intensity) 442 (M+, 12), 373 (31), 240 (5), 173 (22),
145 (28), 105 (100), 91 (17), 77 (60); IR (neat) 3069, 2942, 1709,

1028
S.L. Jeon et al. / Journal of Fluorine Chemistry 129 (2008) 1018–1028
1374, 1266, 1194, 1085, 841, 754, 697 cmꢀ1. Anal. Calcd. for
19H11F9O2: C, 51.60; H, 2.51. Found: C, 51.32; H, 2.45%.
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C
Acknowledgements
This work was supported by grant no. R05-2003-000-10308-0
from the Basic Research Program of the Korea Science and
Engineering Foundation.
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