Divergent preparation of allenyl tosylates and α-tosyloxy ketones by facile and efficient isomerization of CF3-containing propargylic tosylates

Article abstract of DOI:10.1016/j.jfluchem.2010.01.003

Treatment of trifluoromethylated propargylic tosylates with hydroxides in a water-organic biphasic solvent system efficiently led to isomerization to allenyl tosylates or hydration to α-tosyloxy ketones at room temperature, just by selection of appropriat

Full text of DOI:10.1016/j.jfluchem.2010.01.003

Journal of Fluorine Chemistry 131 (2010) 646–651
Contents lists available at ScienceDirect
Journal of Fluorine Chemistry
journal homepage: www.elsevier.com/locate/fluor
Short communication
Divergent preparation of allenyl tosylates and
a-tosyloxy ketones by facile and
efficient isomerization of CF3-containing propargylic tosylates
*
Yohsuke Watanabe, Takashi Yamazaki
Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei 184-8588, Japan
A R T I C L E I N F O
A B S T R A C T
Article history:
Treatment of trifluoromethylated propargylic tosylates with hydroxides in a water-organic biphasic
Received 9 November 2009
Received in revised form 4 January 2010
Accepted 7 January 2010
Available online 14 January 2010
solvent system efficiently led to isomerization to allenyl tosylates or hydration to
room temperature, just by selection of appropriate reaction conditions.
a-tosyloxy ketones at
ß 2010 Elsevier B.V. All rights reserved.
Keywords:
Propargylic alcohols
Allenes
Hydration
Trifluoromethyl
1. Introduction
2. Results and discussion
Trifluoromethyl-containing molecules are very attractive be-
cause of their inherent properties applicable to pharmaceutical,
agrochemical and advanced material fields [1]. However, com-
mercially available sources of fluorinated molecules are structur-
ally limited so that even simple compounds have to be prepared by
ourselves and thus endeavors have still been required to develop
novel synthetic routes, allowing ready access to a wide variety of
organofluorine compounds. In continuing our application of
trifluoromethylated propargylic alcohols as CF3-containing build-
ing blocks [2], we have focused our attention for isomerization of
propargylic tosylates 2 to the corresponding allenyl tosylates 3,
which was inspired by facile conversion of electron-deficient
propargylic alcohols to (E)-enones through allenyl intermediates
under basic conditions (Scheme 1) [3]. Moreover, hydration of 2 is
also demonstrated in this communication for direct transforma-
Toluenesulfonates 2 employed in this study were obtained from
these alcohols 1 whose condensation with p-toluenesulfonyl
chloride (TsCl) was successfully mediated by Et3N and a catalytic
amount of 4-(dimethylamino)pyridine. However, 2a was the
exception which was prepared from the alcohol 1a and TsCl in
the presence of Ag2O and KI [7] because of decomposition of 2a
under the former reaction condition. A solution of 2 (1.0 equiv) in
THF was treated with 1 M aq NaOH (3.0 equiv) at room
temperature and the reaction mixture was quenched with 1 M
aq HCl. Table 1 summarized the results of the present facile
isomerization with various tosylates. It is understood that
tosylates 2bꢀ2g (Table 1, entries 2–7) with an aliphatic substitu-
ent at the propargylic position afforded the desired allenyl
tosylates 3b–3g in excellent yields but only a complex mixture
was formed from 2a (Table 1, entry 1) with a phenyl moiety at the
same site. This was presumably due to instability of 2a under this
basic condition by ‘‘triple activation’’ of the benzyl proton which, at
tion to hitherto unknown
a
-tosyloxy-a0-trifluoromethyl ketones
4. Because the corresponding non-fluorinated counterparts are
recognized as significantly important building blocks for the
construction of lactones and heteroaromatics such as pyrazoles,
imidazoles, oxazoles, thiazoles, selenazoles and pyridines [4–6],
these ketones 4 would have importance and value as long as they
can tolerate under reaction conditions employed.
the same time, is
a to the electronically inductive OTs and the
propargylic position whose triple bond possesses a CF3 group as
the terminal substituent [8]. It is interesting to note that
transformation of non-fluorinated propargylic tosylate 2h did
not proceed at all (Table 1, entry 8), which was nicely compared
with the case shown in entry 2 and unambiguously proved the
pivotal role of the strongly electron-withdrawing CF3 group in this
process for efficient increase of acidity of this proton.
During the course of optimization of reaction conditions, we
discovered that addition of DMF to the mixture containing 3
* Corresponding author. Tel.: +81 42 388 7038; fax: +81 42 388 7038.
E-mail address: tyamazak@cc.tuat.ac.jp (T. Yamazaki).
0022-1139/$ – see front matter ß 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.jfluchem.2010.01.003

Y. Watanabe, T. Yamazaki / Journal of Fluorine Chemistry 131 (2010) 646–651
647
Table 2
Hydration of propargylic tosylates 2
.
Scheme 1. Isomerization of propargylic alcohols A to E-enones B.
Entry
Time (h)
4
Yielda (%)
5
Yielda (%)
1
2
5
24
24
24
24
48
4b
4c
4d
4e
4f
76
61
58
26
41
0
5b
5c
5d
5e
5f
17
12
14
16
ꢀ
3
4b
5c
6b,d
4g
5g
0
a
Isolated yield.
b
c
This reaction was carried out in THFꢀH2OꢀDMF (2:1:1).
19F NMR yield using PhCF3 as an internal standard.
The second step was carried out at 90 8C.
d
3). Meanwhile, low-yield formation of 4 was noticed for the
secondary alkylated tosylates 2e and f, with the product of the
latter 4f being unable to be purified by silica gel column
chromatography due to its instability (Table 2, entries 4 and 5).
Additionally, the tertiary alkylated tosylate 2g could not afford the
corresponding ketone 4g at all.
These results can be explained by the mechanism shown in
Scheme 2. After base-mediated isomerization of propargylic
tosylates 2 to allenyl tosylates 3, hydroxide ion would cause the
transformation to 4 by possible initiation by nucleophilic attack at
the electropositive sulfonyl sulfur atom to furnish the cyclic
intermediate 6. Selective cleavage of the S–O bond would proceed
so as to afford energetically more favorable intermediate 7
stabilized by intramolecular Na. . .F interaction rather than 8,
which led to the formation of the desired
a-tosyloxy ketones 4.
Further reaction of 4 with an excess amount of hydroxide ion
affected defluorinative decarboxylation to 5 by way of repeated
elimination of fluoride ion [9]. This mechanism consistently
explains the fact that the conversion of 2h to 3h did not occur: thus,
2h with an electron-donating butyl group should destabilize the
anionic intermediate between 3h and 6h which resulted in
suppression of this process.
Scheme 2. Proposed mechanism for the hydration.
further promoted the hydration reaction to yield the correspond-
ing ketone products 4 in good yields (Table 2). When substituents R
were equivalent to primary alkyl groups, the desired tosyloxy
ketones 4 were obtained in good to high yields (Table 2, entries 1–
3. Conclusion
Table 1
In summary, we have developed facile and efficient synthetic
routes which allowed the selective syntheses of both allenyl
Isomerization of 2–3
tosylates 3 and
containing propargylic tosylates
a
-tosyloxy-a0-trifluoromethyl ketones 4 from CF3-
as the single substrates.
2
.
Advantage of the present method is that both allenes 3 and
ketones 4 can be easily prepared only by selection of the condition
whether DMF is added to the reaction mixture after transformation
of 2–3 or not. Further synthetic study on the scope and limitation of
this hydration and application of allenyl tosylates are underway in
our laboratory.
Entry
R
2
Time (h)
3
Yield (%)a
b
1
2
Ph
2a
2b
2c
2d
2e
2f
1
5
3a
3b
3c
3d
3e
3f
ꢀ
Ph(CH2)2
C9H19
ꢁ99
90
3
24
24
48
48
48
24
4
BnO(CH2)2
c-Hex
80
4. Experimental
5
ꢁ99
78
6
Ph(MOMO)CH
t-Bu
4.1. General
7
8c
2g
2h
3g
3h
97
0d
Ph(CH2)2
1H, 13C and 19F NMR spectra were recorded (1H: 300 MHz; 13C:
75.5 MHz; 19F: 283 MHz) at rt. (JEOL AL 300 spectrometer) with
Me4Si and CFCl3 as the internal standards in CDCl3. 13C NMR
spectra were obtained with complete proton decoupling. Infrared
a
Isolated yield.
b
c
A complex mixture.
2h possessed a Bu group at the terminal position instead of a CF3 group.
77% recovery of 2h.
d

648
Y. Watanabe, T. Yamazaki / Journal of Fluorine Chemistry 131 (2010) 646–651
(IR) spectra were obtained with a JASCO A-302 spectrometer.
HRMS data were obtained with a JEOL JMS-700 spectrometer and
FAB mass spectra were measured in a positive ion mode. Elemental
analysis was run on a Perkin-Elmer Series II CHNS/O Analyzer.
Anhydrous THF (Cat. No. 41001-85) and CH2Cl2 (Cat. No. 11338-
85) were obtained from Kanto Chemical Co., Inc. and used as
received. DMF was freshly distilled from CaH2. All other reagents
were obtained from commercial sources and used as received. All
reactions were carried out under an atmosphere of argon in dried
glassware with magnetic stirring.
1H), 4.76 (d, J = 6.0 Hz, 1H), 7.26–7.39 (m, 5H); 13C NMR
d 55.6,
65.7, 72.8 (q, J = 52.7 Hz, C–CF3), 79.7, 85.6 (q, J = 6.2 Hz, C–CCF3),
94.4, 113.7 (q, J = 257.4 Hz, CF3), 127.6, 128.3, 128.7, 136.0; 19F
NMR
d
ꢀ52.14 (s). Minor isomer; 1H NMR
d 3.51 (s, 3H), 4.53 (br,
1H), 4.72 (d, J = 6.9 Hz, 1H), 4.77 (d, J = 6.9 Hz, 1H), 4.80 (d,
J = 3.9 Hz, 1H), 7.26–7.39 (m, 5H); 13C NMR
J = 52.7 Hz, C–CF3), 81.3, 85.6 (q, J = 6.2 Hz, C–CCF3), 95.1, 113.8 (q,
J = 257.4 Hz, CF3), 127.2, 128.3, 128.6, 136.2; 19F NMR
d 55.7, 66.0, 73.0 (q,
d
ꢀ51.93 (s).
IR (neat): 650, 701, 731, 758, 849, 921, 986, 1036, 1078, 1106, 1146,
1214, 1278, 1401, 1455, 1496, 2276, 2369, 2786, 2829, 2848, 2897,
Analytical thin layer chromatography (TLC) was routinely used
for monitoring reactions by generally using a mixture of n-hexane
2954, 3000, 3034, 3067, 3091, 3405 cmꢀ1
.
Anal. calcd for
C13H13O3F3: C, 56.94; H, 4.78; found: C, 56.71; H, 4.61.
and ethyl acetate (v/v). Spherical neutral silica gel (63–210
mm or
40–50 m) was employed for column chromatography and flush
chromatography, respectively.
m
4.3.2. 1,1,1-Trifluoro-6-phenyl-4-(p-toluenesulfonyloxy)hex-2-yne
(2b)
Yield: 94%. White solid. mp: 48 8C. Rf = 0.46 (n-hexane/EtOAc,
4.2. Experimental procedure
4:1, v/v). 1H NMR
d
2.45 (s, 3H), 2.71–2.84 (m, 2H), 2.71–2.84 (m,
2H), 7.13–7.36 (m, 7H), 7.80 (d, J = 8.4 Hz, 2H); 13C NMR
d
21.6,
4.2.1. Procedure for preparation of 5,5,5-trifluoro-2-
30.5, 36.4, 68.3, 74.3 (q, J = 52.9 Hz, C–CF3), 81.9 (q, J = 6.4 Hz, C–
CCF3), 113.2 (q, J = 257.9 Hz, CF3), 126.6, 128.1, 128.4, 128.7, 129.7,
[(methoxy)methoxy]pent-3-yn-2-ol (1f)
To a solution of diisopropylamine (12.1 mL, 86 mmol) in THF
(80 mL) at 0 8C was added dropwise a 1.6 M solution of n-BuLi in
hexane (53.8 mL, 86 mmol) and the mixture was stirred for 30 min
at that temperature. The resultant LDA mixture was cooled to
ꢀ80 8C, and 2-bromo-3,3,3-trifluoropropene (4.5 mL, 43 mmol) in
THF (5 mL) was slowly added at ꢀ80 8C. After the solution was
stirred for 5 min, 2-(methoxymethoxy)-2-phenylethanal (7.7 g,
43 mmol) was added and the whole was stirred for 1.5 h at that
temperature. The reaction mixture was quenched with 1 M HCl aq.
and extracted with EtOAc three times. Concentration after drying
over MgSO4 furnished a crude mixture that was purified by
distillation under reduced pressure to afford 1f (8.8 g, 75%, DR
76:24). Other fluorinated propargylic alcohols were synthesized by
using Ref. [10] procedure.
133.0, 139.2, 145.7; 19F NMR
d
ꢀ52.53 (s). NMR spectra are in
agreement with the published data [8h].
4.3.3. 1,1,1-Trifluoro-4-(p-toluenesulfonyloxy)tridec-2-yne (2c)
Yield: 98%. Colorless oil. Rf = 0.64 (n-hexane/EtOAc, 4:1, v/v). 1H
NMR
2H), 2.45 (s, 3H), 5.09 (tq, J = 6.6, 3.0 Hz, 1H), 7.36 (d, J = 7.8 Hz, 2H),
7.81 (d, J = 8.4 Hz, 2H); 13C NMR
14.0, 21.5, 22.6, 24.3, 28.6, 29.21,
d 0.88 (t, J = 6.6 Hz, 3H), 1.20–1.47 (m, 14H), 1.76–1.95 (m,
d
29.22, 29.3, 31.8, 34.7, 69.2, 74.1 (q, J = 53.3 Hz, C–CF3), 82.2 (q,
J = 6.2 Hz, C–CCF3), 113.4 (q, J = 258.2 Hz, CF3), 128.1, 129.8, 133.1,
145.6; 19F NMR
d
ꢀ52.38 (s). IR (neat): 2954, 2928, 2857, 1711,
1599, 1467, 1378, 1280, 1212, 1192, 1179, 1151, 1096, 957, 918,
887, 814, 669, cmꢀ1. HRMS (FAB): m/z calcd for C20H28O3F3S
[M+H]+: 405.1711; found: 405.1741.
4.2.2. Typical procedure for preparation of allenyl tosylates (3)
To a solution of 2a (0.153 g, 0.40 mmol) in THF (2.4 mL) was
added a 1 M NaOH aq. solution (1.2 mL) at r.t. and the solution was
stirred at that temperature for 5 h. The reaction mixture was
quenched with a 1 M HCl aq. solution (3 mL) and extracted with
EtOAc (3 ꢂ 15 mL). Concentration by rotary evaporator after dried
over Na2SO4 furnished 3b in an almost pure state. If necessary, the
residue was purified by short column chromatography (hexane–
EtOAc, 8:1) to give pure allenyl tosylate 3b (0.153 g, quant).
4.3.4. 6-(Benzyloxy)-1,1,1-trifluoro-4-(p-toluenesulfonyloxy)hex-2-
yne (2d)
Yield: 59%. Colorless oil. Rf = 0.53 (n-hexane/EtOAc, 4:1, v/v). 1H
NMR
J = 11.7 Hz,1H), 4.48(d,J = 12.0 Hz,1H), 5.39(ddq, J = 8.1, 5.4, 2.7 Hz,
1H), 7.27–7.38 (m, 7H), 7.81 (d, J = 8.4 Hz, 2H); 13C NMR
21.5, 35.3,
d2.03–2.23 (m, 2H), 2.42 (s, 3H), 3.55 (t, J = 5.7 Hz, 2H), 4.41 (d,
d
64.2, 66.4 (q, J = 1.3 Hz, CH–OTs), 73.2, 74.1 (q, J = 52.1 Hz, C–CF3),
82.1 (q, J = 6.2 Hz, C–CCF3), 113.3 (q, J = 257.9 Hz, CF3), 127.7, 127.8,
128.1, 128.4, 129.9, 132.9, 137.7, 145.6; 19F NMR
d
ꢀ52.57 (s). IR
(neat): 2963, 2933, 2871, 2275, 1722, 1598, 1496, 1455, 1376, 1277,
1211, 1192, 1148, 1098, 1070, 1030, 1020, 957, 940, 853, 816, 788,
749, 699, 669 cmꢀ1. HRMS (FAB): m/z calcd for C20H20O4F3S [M+H]+:
413.1034; found: 413.1045.
4.2.3. Typical procedure for preparation of
a-tosyloxyketones (4)
To a solution of 2a (0.153 g, 0.40 mmol) in THF (2.1 mL) was
added a 1 M NaOH aq. solution (1.2 mL) at r.t. The solution was
stirred at that temperature for 4 h before addition of DMF (0.3 mL).
After the resulting solution was stirred for additional 1 h, the
reaction mixture was quenched with a 1 M HCl aq. solution (3 mL)
and extracted with hexane–EtOAc (1:1, 3ꢂ 15 mL). Concentration
by rotary evaporator after dried over Na2SO4 furnished a crude
mixture that was purified by silica gel chromatography (hexane–
EtOAc, 18:1) to afford 4b (0.121 g, 76%).
4.3.5. 4-Cyclohexyl-1,1,1-trifluoro-4-(p-toluenesulfonyloxy)but-2-
yne (2e)
Yield: 88%. White solid. mp: 66 8C. Rf = 0.62 (n-hexane/EtOAc,
4:1, v/v). 1H NMR
d
0.99–1.32 (m, 5H), 1.61–1.85 (m, 6H), 2.44 (s,
3H), 4.91 (dq, J = 5.4, 2.7 Hz, 1H), 7.36 (d, J = 7.8 Hz, 2H), 7.81 (d,
J = 8.4 Hz, 2H); 13C NMR
21.5, 25.2, 25.3, 25.7, 27.7, 27.8, 41.9,
d
73.4 (q, J = 1.2 Hz, CH–OTs), 74.7 (q, J = 53.3 Hz, C–CF3), 81.4 (q,
J = 6.8 Hz, C–CCF3), 113.3 (q, J = 257.4 Hz, CF3), 128.0, 129.8, 133.0,
4.3. Experimental data
145.5; 19F NMR
d
ꢀ52.18 (s). IR (CH2Cl2): 2935, 2858, 1599, 1452,
4.3.1. 5,5,5-Trifluoro-2-[(methoxy)methoxy]pent-3-yn-2-ol (1f)
IR (neat): 650, 701, 731, 758, 849, 921, 986, 1036, 1078, 1106,
1146, 1214, 1278, 1401, 1455, 1496, 2276, 2369, 2786, 2829, 2848,
2897, 2954, 3000, 3034, 3067, 3091, 3405 cmꢀ1. Anal. calcd for
1373, 1339, 1280, 1212, 1190, 1178, 1154, 1096, 965, 935, 916,
897, 887, 844, 829, 813, 787, 745, 670 cmꢀ1. HRMS (FAB): m/z calcd
for C17H19O3F3SNa [M+Na]+: 383.0905; found: 383.0876.
C
13H13O3F3: C, 56.94; H, 4.78; found: C, 56.71; H, 4.61. DR 76:24.
Yield: 75%. Colorless oil. bp: 150 8C (2.3 mmHg). Rf = 0.23 (n-
hexane/EtOAc, 3:1, v/v). Major isomer; 1H NMR
3.43 (s, 3H), 4.58
(quint, J = 3.0 Hz, 1H), 4.64 (d, J = 6.6 Hz, 1H), 4.68 (d, J = 6.9 Hz,
4.3.6. 1,1,1-Trifluoro-5-[(methoxy)methoxy]-5-phenyl-4-(p-
toluenesulfonyloxy)pent-2-yne (2f)
IR (neat): 3066, 3035, 2999, 2955, 2895, 2847, 2828, 2274,
1598, 1495, 1455, 1377, 1279, 1214, 1190, 1153, 1104, 1037, 1020,
d

Y. Watanabe, T. Yamazaki / Journal of Fluorine Chemistry 131 (2010) 646–651
649
959, 922, 903, 870, 810, 783, 758, 701, 667 cmꢀ1. HRMS (FAB): m/z
4.3.11. 6-(Benzyloxy)-1,1,1-trifluoro-4-(p-toluenesulfonyloxy)hexa-
2,3-diene (3d)
Yield: 80%. Colorless oil. Rf = 0.46 (n-hexane/EtOAc, 4:1, v/v). 1H
NMR 2.45 (s, 3H), 2.57–2.62 (m, 2H), 3.52 (dt, J = 9.9, 6.0 Hz, 1H),
3.57 (dt, J = 9.9, 6.0 Hz, 1H), 4.41 (d, J = 15.6 Hz, 1H), 4.46 (d,
J = 15.6 Hz, 1H), 5.74 (qt, J = 5.7, 3.0 Hz, 1H), 7.24–7.36 (m, 7H),
7.75–7.79 (m, 2H); 13C NMR
d 21.6, 32.6, 65.4, 73.0, 96.3 (q,
calcd for C20H20O5F3S [M+H]+: 429.0984; found: 429.1029. DR
74:26. Yield: 89%. Colorless oil. Rf = 0.57 (n-hexane/EtOAc, 4:1, v/
v). Major; 1H NMR
d
2.43 (s, 3H), 3.34 (s, 3H), 4.55 (d, J = 6.6 Hz, 1H),
4.61 (d, J = 6.6 Hz, 1H), 4.85 (d, J = 6.9 Hz, 1H), 5.27 (dq, J = 6.9,
2.7 Hz, 1H), 7.26–7.37 (m, 7H), 7.76 (d, J = 8.4 Hz, 2H); 13C NMR
d
d
21.5, 55.8, 71.6 (q, J = 1.2 Hz, CH–OTs), 75.5 (q, J = 53.3 Hz, C–CF3),
77.4, 80.0 (q, J = 6.8 Hz, C–CCF3), 94.5, 113.1, (q, J = 258.0 Hz, CF3),
J = 39.7 Hz, C–CF3), 120.6 (q, J = 271.7 Hz, CF3), 127.5, 127.6, 128.30,
128.34, 128.7, 129.8, 132.2, 137.8, 145.7 (q, J = 0.7 Hz, C–C55CCF3),
127.8, 128.0, 128.5, 129.2, 129.7, 132.8, 134.5, 145.7; 19F NMR
d
ꢀ52.97 (d, J = 4.5 Hz). Minor; 1H NMR 2.43 (s, 3H), 3.37 (s, 3H), 4.56
(d, J = 6.9 Hz, 1H), 4.61 (d, J = 6.6 Hz, 1H), 4.92 (d, J = 5.4 Hz, 1H),
5.16 (dq, J = 3.0, 3.0 Hz, 1H), 7.26–7.37 (m, 7H), 7.66 (d, J = 8.4 Hz,
2H); 13C NMR 21.5, 55.8, 71.5 (q, J = 1.2 Hz, CH–OTs), 74.9 (q,
J = 52.7 Hz, C–CF3), 77.1, 80.4 (q, J = 6.2 Hz, C–CCF3), 94.2, 113.3, (q,
J = 258.0 Hz, CF3), 127.6, 128.0, 128.5, 129.1, 129.8, 132.5, 134.7,
145.7; 19F NMR ꢀ52.67 (d, J = 4.5 Hz).
199.6 (q, J = 5.6 Hz, C–CCF3); 19F NMR
d
ꢀ63.40 (d, J = 6.8 Hz). IR
(neat): 2867, 1598, 1454, 1436, 1415, 1380, 1308, 1273, 1195,
1181, 1133, 1091, 1060, 972, 851, 815, 740, 699, 680, 659 cmꢀ1
.
HRMS (FAB): m/z calcd for C20H20O4F3S [M+H]+: 413.1034; found:
413.1051.
4.3.12. 4-Cyclohexyl-1,1,1-trifluoro-4-(p-toluenesulfonyloxy)buta-
2,3-diene (3e)
4.3.7. 1,1,1-Trifluoro-5,5-dimethyl-4-(p-toluenesulfonyloxy)hex-2-
yne (2g)
Yield: quant. Colorless oil. Rf = 0.63 (n-hexane/EtOAc, 4:1, v/v).
1H NMR
d
0.95–1.32 (m, 5H), 1.61–1.85 (m, 5H), 2.20 (tq, J = 11.1,
3.3 Hz, 1H), 2.45 (s, 3H), 5.78 (qd, J = 5.7, 3.0 Hz, 1H), 7.32–7.37 (m,
2H), 7.75–7.79 (m, 2H); 13C NMR
21.6, 25.35, 25.37, 25.7, 29.48,
29.52, 96.2 (q, J = 39.0 Hz, C–CF3), 120.8 (q, J = 271.7 Hz, CF3), 128.3,
129.8, 132.5, 135.3, 146.6, 198.4 (q, J = 5.6 Hz, C–CCF3); 19F NMR
ꢀ63.61 (d, J = 4.5 Hz). IR (neat): 2934, 1404, 1373, 1292, 1218,
Yield: 95%. White solid. mp: 64–67 8C. Rf = 0.63 (n-hexane/
EtOAc, 4:1, v/v). 1H NMR
d
1.03 (s, 9H), 2.45 (s, 3H), 4.77 (q,
J = 2.7 Hz, 1H), 7.36 (d, J = 8.1 Hz, 2H), 7.81 (d, J = 8.1 Hz, 2H); 13C
NMR 21.4, 25.0, 36.0, 74.7 (q, J = 53.3 Hz, C–CF3), 77.2, 81.4 (q,
J = 6.8 Hz, C–CCF3), 113.3 (q, J = 258.0 Hz, CF3), 128.1, 129.8, 133.0,
145.6; 19F NMR
d
d
d
d
ꢀ52.35 (s); IR (CH2Cl2): 2974, 1370, 1279, 1246,
1192, 1179, 1152, 1134, 1086, 1004, 829, 815, 739, 665 cmꢀ1
.
1213, 1191, 1178, 1153, 956, 936, 897, 840, 814, 771, 704,
672 cmꢀ1. Anal. calcd for C15H17O3F3S: C, 53.88; H, 5.12; found: C,
53.43; H, 5.51.
HRMS (FAB): m/z calcd for C17H19O3F3S [M]+: 360.1007; found:
360.1034.
4.3.13. 1,1,1-Trifluoro-5-[(methoxy)methoxy]-5-phenyl-4-(p-
toluenesulfonyloxy)penta-2,3-diene (3f)
DR: 50:50. Yield: 78%. Colorless oil. Rf = 0.47 (n-hexane/EtOAc,
4:1, v/v). 1H NMR
d 2.44 (s, 6H), 3.32 (s, 6H), 4.53 (d, J = 6.9 Hz, 1H),
4.3.8. 1-Phenyl-3-(p-toluenesulfonyloxy)non-4-yne (2h)
Yield: 40%. Colorless oil. Rf = 0.50 (n-hexane/EtOAc, 4:1, v/v). 1H
NMR
d
0.86 (t, J = 7.2 Hz, 3H), 1.23–1.33 (m, 4H), 1.98–2.14 (m, 4H),
2.44 (s, 3H), 2.65–2.82 (m, 2H), 5.08 (tt, J = 6.3, 1.8 Hz, 1H),
4.55 (d, J = 7.2 Hz, 1H), 4.63 (d, J = 6.6 Hz, 1H), 4.66 (d, J = 6.6 Hz,
1H), 5.27 (t, J = 2.1 Hz, 2H), 5.87 (qd, J = 5.7, 2.1 Hz, 1H), 5.89 (qd,
J = 5.7, 2.1 Hz, 1H), 7.23–7.35 (m, 14H), 7.61–7.67 (m, 4H); 13C
7.13 ꢀ 7.33 (m, 7H), 7.79–7.83 (m, 2H); 13C NMR
d 13.4, 18.2, 21.6,
21.7, 30.1, 30.8, 37.7, 72.0, 75.2, 89.8, 126.1, 128.0, 128.36, 128.42,
129.4, 134.3, 140.3, 144.4. IR (neat): 2957, 2932, 2871, 1600, 1496,
1455, 1366, 1189, 1175, 1097, 895, 814, 749, 700, 667 cmꢀ1. HRMS
(FAB): calcd for C22H28O3S [M+2H]+: 372.1759; found: 372.1798.
NMR
d 21.6, 55.65, 55.68, 75.1, 75.2, 94.2, 98.0 (q, J = 39.8 Hz, C–
CF3), 98.1 (q, J = 39.1 Hz, C–CF3), 120.6, (q, J = 271.7 Hz, CF3), 120.7,
(q, J = 271.7 Hz, CF3), 127.27, 127.32, 128.25, 128.29, 128.4, 128.7,
129.4, 129.5, 129.7, 131.91, 131.93, 135.9, 136.0, 145.7, 198.7, (q,
4.3.9. 1,1,1-Trifluoro-6-phenyl-4-(p-toluenesulfonyloxy)hexa-2,3-
diene (3b)
J = 5.6 Hz, C–CCF3), 198.8, (q, J = 6.2 Hz, C–CCF3); 19F NMR
d
ꢀ63.18
(d, J = 4.5 Hz), ꢀ63.11 (d, J = 4.5 Hz). IR (neat): 2928, 1721, 1674,
1598, 1450, 1365, 1307, 1271, 1191, 1178, 1139, 1097, 1020, 994,
816, 768, 699, 661 cmꢀ1. HRMS (FAB): m/z calcd for C20H21O5F3S
[M+2H]+: 430.1063; found: 430.1082.
Yield: quant. Colorless oil. Rf = 0.70 (n-hexane/EtOAc, 4:1, v/v).
1H NMR
d
2.45 (s, 3H), 2.56–2.63 (m, 2H), 2.70–2.76 (m, 2H), 5.66
(qt, J = 5.7, 3.0 Hz, 1H), 7.09–7.35 (m, 7H), 7.75–7.79 (m, 2H). 13C
NMR (75.5 MHz, CDCl3): 21.3, 31.6, 33.2, 96.2 (q, J = 39.1 Hz, C–
d
CF3), 120.5 (q, J = 271.6 Hz, CF3), 126.2, 128.1, 128.2, 128.3, 129.8,
130.3, 132.1, 139.3, 145.7, 199.3 (q, J = 5.6 Hz, C–CCF3). 19F NMR
4.3.14. 1,1,1-Trifluoro-5,5-dimethyl-4-(p-toluenesulfonyloxy)hexan-
2-one (3g)
(283 MHz, CDCl3):
d
ꢀ63.38 (t, J = 6.9 Hz). IR (neat): 3030, 2928,
Yield: 97%. Colorless oil. Rf = 0.63 (n-hexane/EtOAc, 4:1, v/v). 1H
1737, 1598, 1496, 1454, 1437, 1418, 1376, 1271, 1214, 1195, 1181,
1145, 1128, 1087, 1071, 1033, 940, 865, 846, 819, 745, 700, 680,
.
650 cmꢀ1 HRMS (FAB): m/z calcd for C19H18O3F3S [M+H]+:
NMR
(m, 2H), 7.76–7.80 (m, 2H); 13C NMR
J = 39.1 Hz, C–CF3), 120.9 (q, J = 271.0 Hz, CF3), 128.3, 129.8, 132.7,
138.0, 145.6, 196.6 (q, J = 6.2 Hz, C–CCF3); 19F NMR
d
1.07 (s, 9H), 2.45 (s, 3H), 5.85 (q, J = 5.7 Hz, 1H), 7.32–7.36
d
21.6, 27.1, 34.9, 97.7 (q,
383.0929; found: 383.0950.
d
ꢀ63.52 (d,
J = 6.8 Hz). IR (neat): 2360, 1419, 1381, 1269, 1195, 1180, 1128,
1048, 861, 776, 741, 661 cmꢀ1. HRMS (FAB): m/z calcd for
4.3.10. 1,1,1-Trifluoro-4-(p-toluenesulfonyloxy)trideca-2,3-diene
(3c)
C
15H18O3F3S [M+H]+: 335.0929; found: 335.0969.
Yield: 98%. Colorless oil. Rf = 0.74 (n-hexane/EtOAc, 4:1, v/v). 1H
NMR
3.0 Hz, 2H), 2.46 (s, 3H), 5.73 (qt, J = 5.7, 3.0 Hz, 1H), 7.33–7.37 (m,
2H), 7.76–7.81 (m, 2H). 13C NMR
14.1, 21.6, 22.6, 25.3, 28.4, 29.1,
d
0.88 (t, J = 6.8 Hz, 3H), 1.18–1.41 (m, 14H), 2.27 (td, J = 7.5,
4.3.15. 1,1,1-Trifluoro-6-phenyl-4-(p-toluenesulfonyloxy)hexan-3-
one (4b)
d
Yield: 76%. Colorless oil. Rf = 0.43 (n-hexane/EtOAc, 4:1, v/v). 1H
29.2, 29.3 31.786, 31.794, 96.1 (q, J = 39.8 Hz, C–CF3), 120.7 (q,
J = 271.7 Hz, CF3), 128.4, 129.8, 131.4, 132.4, 145.7 (q, J = 0.6 Hz, C–
NMR d 1.91–2.10 (m, 2H), 2.39–2.49 (m, 1H), 2.47 (s, 3H), 2.58
(ddd, J = 14.7, 9.3, 6.0 Hz, 1H), 3.40 (dq, J = 18.0, 9.9 Hz, 1H), 3.50
(dq, J = 18.0, 9.9 Hz, 1H), 4.65 (dd, J = 7.8, 5.1 Hz, 1H), 6.96–6.98 (m,
2H), 7.17–7.25 (m, 3H), 7.38 (d, J = 8.1 Hz, 2H), 7.79 (d, J = 8.4 Hz,
C55CCF3), 199.3 (q, J = 6.0 Hz, C–CCF3). 19F NMR
d
ꢀ63.38 (d,
J = 6.8 Hz). IR (neat): 2957, 2927, 2857, 1599, 1466, 1418, 1379,
1306, 1283, 1213, 1193, 1179, 1129, 1088, 1020, 900, 841, 815,
785, 717, 687, 665 cmꢀ1. HRMS (FAB): m/z calcd for C20H27O3F3S
[M]+: 404.1633; found: 404.1590.
2H). 13C NMR (75.5 MHz, CDCl3):
d 21.7, 30.4, 32.7, 41.7 (q,
J = 29.1 Hz, C–CF3), 82.8 (q, J = 1.8 Hz, CH–OTs), 123.4 (q,
J = 276.7 Hz, CF3), 126.5, 128.1, 128.3, 128.6, 130.2, 132.1, 139.2,

650
Y. Watanabe, T. Yamazaki / Journal of Fluorine Chemistry 131 (2010) 646–651
146.0, 197.2 (q, J = 2.5 Hz, C–CCF3). 19F NMR (283 MHz, CDCl3):
d
1097, 969, 944, 888, 841, 814, 667 cmꢀ1. HRMS (FAB): m/z calcd for
20H30O4F3S [M+2H]+: 356.2021; found: 356.2027.
ꢀ63.66 (t, J = 6.9 Hz). IR (neat): 3030, 2931, 1742, 1598, 1496,
C
1455, 1410, 1374, 1275, 1192, 1177, 1109, 1051, 1017, 982, 930,
834, 816, 750, 700, 667 cmꢀ1
C
.
HRMS (FAB): m/z calcd for
4.3.21. 5-(Benzyloxy)-3-(p-toluenesulfonyloxy)pentan-2-one (5d)
Yield: 14%. Colorless oil. Rf = 0.39 (n-hexane/EtOAc, 4:1, v/v). 1H
19H20O4F3S [M+H]+: 401.1034; found: 401.1028.
NMR
3.47–3.54 (m, 1H), 4.28 (s, 2H), 4.88 (dd, J = 6.6, 5.1 Hz, 1H), 7.26–
7.38 (m, 5H), 7.77–7.82 (m, 2H); 13C NMR
21.6, 26.1, 31.9, 64.4,
72.8, 81.4, 127.4, 127.6, 127.9, 128.3, 130.1, 132.9, 137.8, 145.3,
205.0. IR (neat): 2927, 1724, 1599, 1454, 1368, 1271, 1190, 1177,
1119, 1029, 1010, 956, 847, 816, 744, 714, 699, 668 cmꢀ1. HRMS
(FAB): m/z calcd for C19H23O5S [M+H]+: 363.1266; found: 363.1255.
d2.19(s,3H), 2.40(s, 3H), 1.97–2.07(m, 2H), 3.32–3.39(m, 1H),
4.3.16. 1,1,1-Trifluoro-4-(p-toluenesulfonyloxy)tridecan-3-one (4c)
Yield: 61%. Colorless oil. Rf = 0.57 (n-hexane/EtOAc, 4:1, v/v).
d
1H NMR
d
0.88 (t, J = 6.6 Hz, 3H), 1.04–1.31 (m, 14H), 1.58–1.78 (m,
2H), 2.47 (s, 3H), 3.43 (dq, J = 18.0, 9.9 Hz, 1H), 3.53 (dq, J = 18.0,
9.9 Hz, 1H), 4.60 (dd, J = 8.1, 4.5 Hz, 1H), 7.37–7.41 (m, 2H), 7.79–
7.82 (m, 2H); 13C NMR
d14.0, 21.6, 22.6, 24.2, 28.6, 29.1, 29.2, 29.3,
31.1, 31.8, 41.6 (q, J = 29.1 Hz, C–CF3), 83.7 (q, J = 1.2 Hz, C–CCF3),
123.4 (q, J = 276.0 Hz, CF3), 128.1, 130.1, 132.1, 145.9, 197.6 (br);
4.3.22. 3-Cyclohexyl-3-(p-toluenesulfonyloxy)propan-2-one (5e)
Yield: 16%. Colorless oil. Rf = 0.47 (n-hexane/EtOAc, 4:1, v/v). 1H
19F NMR
d
ꢀ63.67 (t, J = 9.0 Hz). IR (neat): 2953, 2927, 2856, 1743,
1598, 1466, 1411, 1374, 1277, 1191, 1178, 1125, 1105, 1040, 1020,
982, 943, 912, 887, 842, 815, 771, 723, 707, 688, 667 cmꢀ1. HRMS
NMR
3H), 4.38 (d, J = 5.7 Hz, 1H), 7.34–7.37 (m, 2H), 7.76–7.82 (m, 2H);
13C NMR
21.7, 25.5, 25.6, 25.7, 26.9, 27.3, 28.5, 39.9, 88.4, 128.1,
d 0.85–1.40 (m, 6H), 1.56–1.83 (m, 5H), 2.16 (s, 3H), 2.46 (s,
(FAB): m/z calcd for
C
20H29O4F3S [M]+: 422.1739; found:
d
422.1710.
129.9, 132.8, 145.3, 205.7. IR (neat): 2931, 2856, 1716, 1598, 1451,
1370, 1191, 1177, 1096, 954, 897, 885, 836, 816, 786, 684,
.
668 cmꢀ1 HRMS (FAB): m/z calcd for C16H23O4S [M+H]+:
4.3.17. 6-(Benzyloxy)-1,1,1-trifluoro-4-(p-
toluenesulfonyloxy)hexan-3-one (4d)
311.1317; found: 311.1349.
Yield: 58%. Colorless oil. Rf = 0.43 (n-hexane/EtOAc, 4:1, v/v). 1H
NMR
3.57 (m, 4H), 4.28 (s, 2H), 4.90 (t, J = 5.4 Hz, 1H), 7.17–7.21 (m, 2H),
7.28–7.37 (m, 5H), 7.77–7.81 (m, 2H); 13C NMR
21.5, 31.8, 41.8 (q,
d 1.93–2.03 (m, 1H), 2.09–2.21 (m, 1H), 2.42 (s, 3H), 3.29–
Acknowledgment
d
The authors are grateful to Tosoh F-Tech Inc. for the generous
gift of 2-bromo-3,3,3-trifluoropropene.
J = 29.2 Hz, C–CF3), 63.7, 72.8, 80.7 (q, J = 1.2 Hz, CH–OTs), 123.5 (q,
J = 276.1 Hz, CF3), 127.5, 127.7, 127.9, 128.3, 130.1, 132.3, 137.4,
145.8, 196.9 (q, J = 2.5 Hz, C–CCF3); 19F NMR
J = 10.3 Hz). IR (neat): 1030, 1043, 1101, 1191, 2930, 2871,
d
ꢀ63.92 (t,
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20H22O5F3S [M+H]+: 431.1140; found: 431.1168.
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2.47 (s, 3H), 3.43 (q, J = 9.9 Hz, 2H), 4.39 (d, J = 6.0 Hz, 1H), 7.37–
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J = 1.8 Hz, C–CCF3); 19F NMR
d
ꢀ63.73 (t, J = 9.0 Hz). IR (neat): 2934,
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.
HRMS (FAB): m/z calcd for C17H22O4F3S [M+H]+: 379.1191; found:
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379.1178.
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NMR
3H), 4.65 (dd, J = 7.8, 5.1 Hz, 1H), 6.99–7.02 (m, 2H), 7.17–7.25 (m,
3H), 7.36 (d, J = 8.1 Hz, 2H), 7.80 (d, J = 8.1 Hz, 2H); 13C NMR
21.7,
25.9, 30.6, 33.1, 83.7, 126.3, 128.0, 128.3, 128.5, 130.0, 132.8, 139.7,
145.4, 205.1. IR (neat): 2927, 1723, 1598, 1496, 1455, 1418, 1402,
1368, 1279, 1233, 1212, 1191, 1176, 1097, 1019, 928, 815, 749,
701, 668 cmꢀ1. HRMS (FAB): m/z calcd for C18H21O4S [M+H]+:
333.1161; found: 333.1152.
d 1.89–2.09 (m, 2H), 2.20 (s, 3H), 2.42–2.64 (m, 2H), 2.46 (s,
d
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4.3.20. 3-(p-Toluenesulfonyloxy)dodecan-2-one (5c)
Yield: 12%. Colorless oil. Rf = 0.50 (n-hexane/EtOAc, 4:1, v/v). 1H
NMR
2H), 2.21 (s, 3H), 2.46 (s, 3H), 4.58 (dd, J = 8.4, 4.8 Hz, 1H), 7.34–
7.38 (m, 2H), 7.79–7.83 (m, 2H); 13C NMR
14.1, 21.7, 22.6, 24.4,
d 0.88 (t, J = 6.6 Hz, 3H), 1.12–1.31 (m, 14H), 1.56–1.77 (m,
d
25.9, 28.8, 29.188, 29.189, 29.3, 31.4, 31.8, 84.5, 128.0, 129.9, 133.0,
145.3, 205.6. IR (neat): 2926, 2855, 1724, 1465, 1371, 1190, 1178,

Y. Watanabe, T. Yamazaki / Journal of Fluorine Chemistry 131 (2010) 646–651
651
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