Convenient synthesis of 3,3,3-trifluoropropenyl compounds from aromatic aldehydes by means of the TBAF-mediated horner reaction

Article abstract of DOI:10.1021/jo0111311

A simple synthesis of 3,3,3-trifluoropropenyl compounds by means of the TBAF-mediated Horner reaction is described. The reagent, 2,2,2-trifluoroethyldiphenylphosphine oxide, was readily prepared either by Arbuzov reaction of ethyl diphenylphosphinite with 2,2,2-trifluoroethyl iodide or by treating chlorodiphenylphosphine with trifluoroacetic acid and water. Treatment of the phosphine oxide with aromatic aldehydes in the presence of TBAF at room temperature afforded the corresponding 3,3,3-trifluoropropenyl compounds in good yields. The present method is very convenient for preparing 3,3,3-trifluoropropenyl compounds from aromatic aldehydes in terms of availability of the reagent, operational simplicity, and good yields of the products.

Full text of DOI:10.1021/jo0111311

3156
J . Org. Chem. 2002, 67, 3156-3159
Sch em e 1
Con ven ien t Syn th esis of
3,3,3-Tr iflu or op r op en yl Com p ou n d s fr om
Ar om a tic Ald eh yd es by Mea n s of th e
TBAF -Med ia ted Hor n er Rea ction
Tetsuya Kobayashi, Takuya Eda, Osamu Tamura, and
Hiroyuki Ishibashi*
sequence of reactions and the use of expensive and/or low-
boiling reagents.5 One of the most direct routes to
synthesize the trifluoropropenyl structure seems to be
the use of a Wittig-type reaction of an aldehyde with a
trifluoromethyl-containing reagent. Indeed, the Wittig
reaction of 2,2,2-trifluoroethyltriphenylphosphonium tri-
flate with benzaldehyde in the presence of CsF was
reported.6 However, the preparation of the phosphonium
salt requires a multistep sequence of reactions involving
the use of a hypervalent iodine compound.6 The reaction
of triphenylphosphine with 2,2,2-trifluoroethyl iodide
giving phosphonium iodide does not proceed within the
preparative time scale (9 months, 9%).7,8 In this paper,
we report a convenient method for synthesizing 3,3,3-
trifluoropropenyl compounds 3 using the TBAF-mediated
Horner reaction of 2,2,2-trifluoroethyldiphenylphosphine
oxide (2) with aldehydes 1 (Scheme 1).
Faculty of Pharmaceutical Sciences, Kanazawa University,
Takara-machi, Kanazawa 920-0934, J apan
isibasi@mail.p.kanazawa-u.ac.jp
Received December 7, 2001
Abstr a ct: A simple synthesis of 3,3,3-trifluoropropenyl
compounds by means of the TBAF-mediated Horner reaction
is described. The reagent, 2,2,2-trifluoroethyldiphenylphos-
phine oxide, was readily prepared either by Arbuzov reaction
of ethyl diphenylphosphinite with 2,2,2-trifluoroethyl iodide
or by treating chlorodiphenylphosphine with trifluoroacetic
acid and water. Treatment of the phosphine oxide with
aromatic aldehydes in the presence of TBAF at room
temperature afforded the corresponding 3,3,3-trifluoropro-
penyl compounds in good yields. The present method is very
convenient for preparing 3,3,3-trifluoropropenyl compounds
from aromatic aldehydes in terms of availability of the
reagent, operational simplicity, and good yields of the
products.
Resu lts a n d Discu ssion s
The starting phosphine oxide 2 could readily be pre-
pared from ethyl diphenylphosphinite (4) by Michaelis-
Arbuzov reaction with 2,2,2-trifluoroethyl iodide (5) in
81% yield (Scheme 2). Sartori and Mosler reported an
alternative method for the preparation of 2 that consisted
of treating chlorodiphenylphosphine (6) with trifluoro-
acetic acid and water at 180 °C for 80 h.9 So, we then
examined the modification of Sartori’s procedure and
found that treatment of 6 with a mixture of trifluoroacetic
acid and water at 0 °C to room temperature for 30 min,
followed by heating around 100 °C for 2 h, afforded 2 in
It is well-known that the introduction of a fluorine
atom into biologically active compounds often intensifies
their activities and chemical and/or biological stabilities.1
Among fluorine-containing groups, a 3,3,3-trifluoropro-
penyl structure (CF3CHdCH-) has been found in can-
didates for medicines2 or agricultural chemicals.3 In a
series of pyrethroid-type insecticides, the 3,3,3-trifluoro-
propenyl group contributes to their volatility, which is
essential for exhibiting their activity.3a-d Reactions of the
unsaturated moiety of 3,3,3-trifluoropropenyl compounds
have also been widely investigated.4 While a variety of
methods have been developed for synthesizing 3,3,3-
trifluoropropenyl compounds, the methods have several
disadvantages, such as the requirement of a multistep
(5) (a) Drakesmith, F. G.; Stewart, O. J .; Tarrant, P. J . Org. Chem.
1968, 33, 280. (b) Sakai, T. T.; Santi, D. V. J . Med. Chem. 1973, 16,
1079. (c) Eliseenkov, E. V.; Koginov, A. S.; Dneprovskii, A. S. Zh. Org.
Khim. 1978, 14, 781. (d) Fuchikami, T.; Yatabe, M.; Ojima, I. Synthesis
1981, 365. (e) Dolbier, W. R., J r.; Medinger, K. S. Tetrahedron 1982,
38, 2411. (f) Kitazume, T.; Ishikawa, N. J . Am. Chem. Soc. 1985, 107,
5186. (g) Yamazaki, T.; Ishikawa, N. Chem. Lett. 1985, 889. (h)
Wiemers, D. M.; Burton, D. J . J . Am. Chem. Soc. 1986, 108, 832. (i)
Fujita, M.; Hiyama, T. Tetrahedron Lett. 1986, 27, 3659. (j) Urata, H.;
Fuchikami, T. Tetrahedron Lett. 1991, 32, 91. (k) Su, D.-B.; Duan, J .-
X.; Chen, Q.-Y. Tetrahedron Lett. 1991, 32, 7689. (l) Tellier, F.;
Sauvetre, R. J . Fluorine Chem. 1993, 62, 183. (m) Mizutani, K.;
Yamazaki, T.; Kitazume, T. J . Chem. Soc., Chem. Commun. 1995, 51.
(n) Furuta, S.; Kuroboshi, M.; Hiyama, T. Bull. Chem. Soc. J pn. 1999,
72, 805. (o) Zang, X.; Qing, F. L.; Yang, Y.; Yu, J .; Fu, X.-K. Tetrahedron
Lett. 2000, 41, 2953. (p) Shimizu, M.; Fujimoto, T.; Minezaki, H.; Hata,
T.; Hiyama, T. J . Am. Chem. Soc. 2001, 123, 6947. See also ref 3a.
(6) (a) Umemoto, T.; Gotoh, Y. Bull. Chem. Soc. J pn. 1987, 60, 3307.
(b) Umemoto, T.; Gotoh, Y. Bull. Chem. Soc. J pn. 1991, 64, 2008. The
method for the preparation of phosphonium salt is as follows. CF3-
CH2I + TFAA + TFA + H2O2 f CF3CH2I(OCOCF3)2; CF3CH2I-
(OCOCF3)2 + TfOH + PhH f CF3CH2I(OTf)Ph; CF3CH2I(OTf)Ph +
Ph3P f Ph3P+CH2CF3 TfO-.
(1) For reviews, see: (a) Schlosser, M. Tetrahedron 1978, 34, 3. (b)
Kobayashi, Y.; Kumadaki, I. Acc. Chem. Res. 1978, 11, 197. (c)
Ishikawa, N. Kagaku No Ryoiki 1981, 35, 441. (d) Filler, R.; Kobayashi,
Y. Biomedicinal Aspects of Fluorine Chemistry; Kodansha, Elsevier
Biomedical: Tokyo, 1982. (e) Welch, J . T. Tetrahedron 1987, 43, 3123.
(f) Resnati, G. Tetrahedron 1993, 49, 9385. (g) Hiyama, T. Organo-
fluorine CompoundssChemistry and Applications; Springer: Berlin,
2000.
(2) (a) Wataya, Y.; Matsuda, A.; Santi, D. V.; Bergstrom, D. E.; Ruth,
J . L. J . Med. Chem. 1979, 22, 339. (b) Bergstrom, D. E.; Ruth, J . L.;
Reddy, P. A.; Clercq, E. D. J . Med. Chem. 1984, 27, 279. (c) Noyori,
R.; Morisawa, Y.; Maeda, T.; Yasuda, S.; Uchida, K. J P-02056462, 1990.
(3) (a) Bentley, P. D.; Cheetham, R.; Huff, R. K.; Pascoe, R.; Sayle,
J . D. Pestic. Sci. 1980, 11, 156. (b) Mack, H.; Hanack, M. Angew. Chem.,
Int. Ed. Engl. 1986, 25, 184. (c) Mack, H.; Hanack, M. Liebigs Ann.
Chem. 1989, 833. (d) Na¨gele, U. M.; Hanack, M. Liebigs Ann. Chem.
1989, 847. (e) Scheiblich, S.; Maier, T.; Baltruschat, H. S.; Hoellmueller,
T. US-6130188, 2000.
(7) Henry, R. A. J . Chem. Eng. Spectrum 1976, 21, 503.
(8) The SN2 reaction scarcely occurs on the carbon R to a trifluo-
romethyl group due to the strong electron-withdrawing nature of the
trifluoromethyl group. See: Shinohara, N.; Yamazaki, T.; Kitazume,
T. Reviews on Heteroatom Chemistry; Oae, S., Ed.; MYU: Toyko, 1996;
pp 165-182. This is the reason the hypervalent iodine compound was
used for the preparation of the phosphonium salt bearing trifluorom-
ethyl group; see ref 6.
(9) (a) Sartori, P.; Mosler, G. Phosphorus Sulfur 1980, 8, 115. See
also: (b) Smith, D. J . H.; Trippett, S. J . Chem. Soc., Perkin Trans. 1
1975, 963.
(4) For leading references, see: (a) Morikawa, T.; Nishiwaki, T.;
Kobayashi, Y. Tetrahedron Lett. 1989, 30, 2407. (b) Hanzawa, Y.;
Suzuki, M.; Kobayashi, Y.; Taguchi, T.; Iitaka, Y. J . Org. Chem. 1991,
56, 1718. (c) Tanaka, K.; Mori, T.; Mitsuhashi, K. Bull. Chem. Soc.
J pn. 1993, 66, 263. (d) Bouvet, D.; Sdassi, H.; Oure´vitch, M.; Bonnet-
Delpon, D. J . Org. Chem. 2000, 65, 2104. (e) Kuroki, Y.; Asada, D.;
Sakamaki, Y.; Iseki, K. Tetrahedron Lett. 2000, 41, 4603.
10.1021/jo0111311 CCC: $22.00 © 2002 American Chemical Society
Published on Web 04/11/2002

Notes
J . Org. Chem., Vol. 67, No. 9, 2002 3157
Sch em e 2
In contrast to the use of TBAF, the use of common
bases such as BuLi, KHMDS, KH, t-BuOK, and Triton
B for the reaction of 1a gave no 3,3,3-trifluoropropenyl
compound 3a . These results are rationalized in terms of
the short lifetime of the anionic intermediate 7 as
mentioned above. For instance, treatment of the phos-
phine oxide 2 with KH gave only the difluorovinyl
compound 8 even in the presence of 1a .15 Compound 8
can no longer regenerate anion 7 due to an insufficient
quantity of fluoride anion. In addition, neither KF nor
CeF worked as a fluoride anion.
The results of Horner reaction of 2 with several
aldehydes 1 giving 3,3,3-trifluoropropenyl compounds 3
are summarized in Table 1 [2 (2 equiv), TBAF (10 equiv),
rt, 1 h]. Benzaldehydes 1b-d also gave the desired
trifluoropropenyl compounds 3b,5c,d,f 3c,5d,n and 3d in good
yields (Table 1, entries 1-3). Reactions of benzaldehydes
having electron-withdrawing groups 1e and 1f gave the
corresponding products 3e and 3f in 64 and 65 yields,
respectively (Table 1, entries 4 and 5). Reaction of
4-acetylbenzaldehyde (1g) also provided trifluoropropenyl
compound 3g, although the yield was low (Table 1, entry
6). Heteroaromatic aldehydes 1h -j yielded products 3h ,
3i,5d and 3j in good yields (Table 1, entries 7-9). The
reaction of trans-cinnamaldehyde (1k ) gave 3k 5d,n in 83%
yield (Table 1, entry 10). However, 3-phenylpropanal (1l)
gave no expected compound 3l (PhCH2CH2CHdCHCF3)
but afforded ester 10 in 60% yield (Table 1, entry 11).
This might be because the deprotonation of the enolizable
aldehyde 1l with fluoride anion competed with that of
phosphine oxide 2 (Scheme 3). Reactions with ketones
such as the benzophenone and 4-tert-butylcyclohexanone
afforded no 3,3,3-trifluoropropenyl compounds.
76% yield without any chromatographic separation (see
the Experimental Section). This modified Sartori’s pro-
cedure is recommended for a large-scale preparation of
2 due to the low prices of the starting materials.
With the phosphine oxide 2 in hand, we initiated our
investigation by examining the reaction of 2 with 2-naph-
thaldehyde (1a ). Reaction of equimolar amounts of 2 with
1a in the presence of TBAF (10 equiv) (pre-dehydrated
with MS 4A in THF) at room temperature for 2 h gave
2-(3,3,3-trifluoropropenyl)naphthalene (3a )5d,n in 73%
yield with recovery of 14% yield of 1a . A similar reaction
using 1.5 equiv of 2 gave 3a in high yield (81%), but a
small amount of the aldehyde was still recovered. The
most satisfactory result was obtained by using 2 equiv
of 2: these conditions gave 3a (E/Z ) 85:15) in 98% yield
after 1 h of reaction. Attempts to reduce the amount of
TBAF gave unsatisfactory results: for example, treat-
ment of 2 (2 equiv) with 1a in the presence of 5 equiv of
TBAF afforded 3a in 50% yield with recovery of 45% yield
of 1a .
A possible mechanism for the Horner reaction of 2 with
1a is as follows. A fluoride anion of TBAF deprotonates
from 2 to generate the phosphinoxy carbanion 7.10,11 The
anion 7 reacts with aldehyde 1a to give the adduct 9,
whose elimination of phosphinate affords the product 3a .
It is assumed that the anion 7 having a trifluoromethyl
group is unstable12,13 and rapidly gives the elimination
product difluorovinylphosphine oxide 8.14 However, the
Michael addition of fluoride anion to 8 can regenerate
7.13a In fact, treatment of difluorovinyl compound 8 (1
equiv), prepared according to the reported procedure,14
with 1a (10 equiv) in the presence of TBAF (10 equiv)
gave 3a in 47% yield.
In summary, the present Horner reaction is quite
convenient for preparing 3,3,3-trifluoropropenyl com-
pounds from aldehydes in terms of availability of reagent
2, operational simplicity, and generally good yields of the
products, although the scope is somewhat limited. A
control of E/Z selectivity of the products and application
to the synthesis of biologically active compounds are
currently under investigation.
Exp er im en ta l Section
Melting points are uncorrected. 1H and 13C NMR spectra were
measured for solutions in CDCl3, CCl4, or benzene-d6. Column
chromatography was performed on Silica gel 60 PF254 under
pressure.
P r ep a r a tion of 2,2,2-Tr iflu or oeth yld ip h en ylp h osp h in e
Oxid e (2). (a ) F r om eth yl d ip h en ylp h osp h in ite (4). A
mixture of ethyl diphenylphosphinite (4) (1.98 g, 5.79 mmol) and
2,2,2-trifluoroethyl iodide (5) (3.60 g, 17.2 mmol) was stirred at
room temperature for 3 h under an argon atmosphere. After
removal of excess 5 by evaporation, the residue was chromato-
graphed on silica gel (AcOEt) to give crude 2. Recrystallization
(11) For a review of synthetic application utilizing the fluoride anion
as a base, see: Clark, J . H. Chem. Rev. 1980, 80, 429.
(12) (a) Nakai, T.; Tanaka, K.; Ishikawa, N. Chem. Lett. 1976, 1263.
(b) Nakai, T.; Tanaka, K.; Setoi, H.; Ishikawa, N. Bull. Chem. Soc.
J pn. 1977, 50, 3069. (c) Aktaev, N. P.; Eremin, O. G.; Sokol’skii, G. A.;
Knunyants, I. L. Izv. Akad. Nauk SSSR, Ser. Khim. 1977, 1117. (d)
Bergstrom, D. E.; Ng, M. W.; Wong, J . J . J . Org. Chem. 1983, 48, 1902.
(13) For generation of an anion R to a trifluoromethyl group, see:
(a) Ishikawa, N.; Yokozawa, T. Bull. Chem. Soc. J pn. 1983, 56, 724.
(b) Fuchigami, T.; Nakagawa, Y. J . Org. Chem. 1987, 52, 5276. (c)
Uneyama, K.; Momota, M. Bull. Chem. Soc. J pn. 1989, 62, 3378.
(14) Ichikawa, J .; J yono, H.; Yonemaru, S.; Okauchi, T.; Minami,
T. J . Fluorine Chem. 1999, 97, 109.
(10) For other fluoride anion-mediated Wittig and Horner reactions,
see: (a) Schiemenz, G. P.; Becker, J .; Sto¨ckigt, J . Chem. Ber. 1970,
103, 2077. (b) Texier-Boullet, F.; Villemin, D.; Ricard, M.; Moison, H.;
Foucaud, A. Tetrahedron 1985, 41, 1259.
(15) Treatment of phosphine oxide 2 with t-BuOK in THF also gave
difluorovinylphosphine oxide 8 in 25% yield.

3158 J . Org. Chem., Vol. 67, No. 9, 2002
Notes
Ta ble 1. Hor n er Rea ction of Ald eh yd es 1 w ith
P h osp h in e Oxid e 2
100 °C for 2 h. After cooling, the mixture was diluted with CHCl3
(200 mL) and concentrated under reduced pressure. To the
residue were added CHCl3 (400 mL) and an aqueous saturated
solution of NaHCO3 (400 mL), and the mixture was stirred
vigorously for 1 h. The organic phase was separated, and the
aqueous phase was extracted with CHCl3 (400 mL × 2). The
combined organic phase was washed successively with an
aqueous saturated solution of NaHCO3 (300 mL × 2) followed
by brine (200 mL × 2) and dried over MgSO4. After filtration,
the filtrate was concentrated under reduced pressure, and the
residue was recrystallized from AcOEt (300 mL) to afford 2 (50.4
g), mp 160-161 °C. The mother liquor was concentrated under
reduced pressure, and the residue was further recrystallized
from AcOEt (80 mL) to afford the second crop of 2 (11.4 g, total
76%), which was sufficiently pure for use.
Gen er a l P r oced u r e for Hor n er Rea ction . MS 4A (powder,
2.4 g) was added to a 1 M solution of TBAF in THF (3.0 mL, 3.0
mmol), and the mixture was stirred at room-temperature
overnight under an argon atmosphere. To the mixture were
added a solution of aldehyde 1 (0.3 mmol) and phosphine oxide
2 (0.6 mmol) in THF (5 mL). After the mixture was stirred for
1 h, MS 4A was removed by filtration. Water (30 mL) was added
to the filtrate, and the whole was extracted with AcOEt. The
extract was washed with brine, dried (MgSO4), and concentrated.
The residue was chromatographed on silica gel (AcOEt-hexane)
to give 3.
2-(3,3,3-Tr iflu or op r op -1-en yl)n a p h th a len e (3a ): colorless
crystals; mp 108-109 °C (3a -E from hexane) (lit.5n mp 108-
109 °C, lit.5d mp 108-108.5 °C); 1H NMR (500 MHz, benzene-
d6) δ 5.38 (15/100 H, dq, J ) 12.7, 9.3 Hz, Z), 5.91 (85/100 H,
dq, J ) 16.1, 6.8 Hz, E), 6.44 (15/100 H, d, J ) 12.7 Hz, Z), 7.00
(85/100 H, dq, J ) 14.6, 2.0 Hz, E), 7.10 (85/100 H, dd, J ) 9.3,
2.0 Hz, E), 7.17-7.55 (6 H, m, E + Z), 7.60 (15/100 H, br s, Z);
1H NMR (500 MHz, CDCl3) δ 5.85 (15/100 H, dq, J ) 12.6, 9.2
Hz, Z), 6.32 (85/100 H, dq, J ) 16.1, 6.4 Hz, E), 7.08 (15/100 H,
d, J ) 12.6 Hz, Z), 7.31 (85/100 H, dq, J ) 16.1, 2.4 Hz, E), 7.49-
7.55 (15/100 + 2 × 85/100 H, m, E + Z), 7.59 (85/100 H, dd, J )
8.8, 2.0 Hz, E), 7.81-7.88 (4 H, m, E + Z); 13C NMR (67.8 MHz,
CDCl3) for E-isomer δ 116.0 (q, J ) 34.2 Hz), 123.1, 123.7 (q, J
) 268.5 Hz), 126.8, 127.2, 127.8, 128.4, 128.8, 129.1, 130.9, 133.3,
134.1, 137.7 (q, J ) 7.4 Hz). The 1H NMR spectrum (in CDCl3)
was identical with that reported.5d,n
(3,3,3-Tr iflu or op r op -1-en yl)ben zen e (3b): colorless oil; 1H
NMR (500 MHz, benzene-d6) δ 5.29 (22/100 H, dq, J ) 12.2, 8.8
Hz, Z), 5.82 (78/100 H, dq, J ) 16.1, 6.3 Hz, E), 6.30 (22/100 H,
d, J ) 12.2 Hz, Z), 6.82-7.05 [(4 + 2 × 78/100) H, m], 7.20 (22/
a
b
Volatile compound. This reaction was carried out by using
1
100 H, d, J ) 6.8 Hz, Z); H NMR (500 MHz, CCl4) δ 5.65 (22/
2 (2 equiv) and TBAF (6 equiv) at -40 °C. c 44% of 1g was
recovered. Ph2P(O)CH2CO2CHdCHCH2Ph (10).
100 H, dq, J ) 12.2, 8.8 Hz, Z), 6.10 (78/100 H, dq, J ) 15.6, 6.3
Hz, E), 7.06 (78/100 H, dq, J ) 15.6, 1.9 Hz, E), 7.21-7.35 (5 H,
m, E + Z); 13C NMR (67.8 MHz, CDCl3) for E-isomer δ 115.9 (q,
J ) 34.2 Hz), 123.6 (q, J ) 268.6 Hz), 127.5, 128.9, 130.0, 133.4.
The 1H NMR spectrum (in CCl4) was identical with that
reported.5c,d,f
d
Sch em e 3
1-(3,3,3-Tr iflu or opr op-1-en yl)-4-m eth oxyben zen e (3c): col-
orless oil; 1H NMR (270 MHz, benzene-d6) δ 3.19 (3 × 5/100 H,
s, Z), 3.21 (3 × 95/100 H, s, E), 5.27 (5/100 H, dq, J ) 12.9, 9.6
Hz, Z), 5.77 (95/100 H, dq, J ) 16.3, 6.8 Hz, E), 6.28 (5/100 H,
d, J ) 12.9 Hz, Z), 6.58 (2 H, br d, J ) 11.0 Hz, E + Z), 6.85 (2
H, br d, J ) 11.0 Hz, E + Z), 6.91 (95/100 H, dq, J ) 16.1, 2.3
Hz, E). 3c-E: 1H NMR (500 MHz, CDCl3) δ 3.84 (3 H, s, OMe),
6.06 (1 H, dq, J ) 16.1, 6.5 Hz), 6.91 (2 H, d, J ) 8.8 Hz) δ 7.09
(1 H, dq, J ) 16.1, 2.3 Hz), 7.39 (2 H, d, J ) 8.8 Hz); 13C NMR
(67.8 MHz, CDCl3) for E-isomer δ 55.3, 113.4 (q, J ) 34.2 Hz),
114.3, 123.9 (q, J ) 268.6 Hz), 126.1, 129.0, 137.1 (q, J ) 7.3
Hz). The 1H NMR spectrum (in CDCl3) was identical with that
reported.5d,n
from AcOEt-hexane gave 2 (1.98 g, 81%) as colorless needles:
mp 160-161 °C (lit.9a mp 155-157 °C); 1H NMR (270 MHz,
CDCl3) δ 3.25 (2 H, dq, J ) 11.8, 10.5 Hz), 7.40-7.64 (6 H, m),
7.72-7.87 (4 H, m). The 1H NMR spectrum was identical with
that reported.9a (b) F r om ch lor od ip h en ylp h osp h in e (6). To
a stirred mixture of trifluoroacetic acid (21.9 mL, 0.284 mol) and
water (15.3 mL, 0.851 mol) was added dropwise phosphine 6
(203.8 mL, 1.135 mol) at 0 °C for 30 min, and the mixture
solidified gradually. When the mixture was allowed to warm to
room temperature, it turned to a pale yellow solution. After 30
min, the mixture was heated within the range between 90 and
1-Ch lor o-4-(3,3,3-tr iflu or op r op -1-en yl)ben zen e (3d ): pale
yellow oil; 1H NMR (500 MHz, benzene-d6) δ 5.24 (18/100 H,
dq, J ) 12.7, 8.8 Hz, Z), 5.64 (82/100 H, dq, J ) 16.1, 6.4 Hz, E),
6.09 (18/100 H, d, J ) 12.7 Hz, Z), 6.53 (2 × 82/100 H, br d, J )
8.3 Hz, E), 6.65 (82/100 H, dq, J ) 16.1, 2.4 Hz, E), 6.87 (2 ×
18/100 H, br d, J ) 8.3 Hz, Z), 6.91 (2 × 82/100 H, br d, J ) 8.3
Hz, E), 6.94 (2 × 18/100 H, br d, J ) 8.3 Hz, Z); HRMS calcd for
C9H635ClF3 206.0111, found 206.0115.
4-(3,3,3-T r iflu o r o p r o p -1-e n y l)b e n ze n e c a r b o n it r ile
(3e): colorless crystals; mp 37-39 °C; 1H NMR (270 MHz,
benzene-d6) δ 5.55 (1 H, dq, J ) 16.0, 6.8 Hz), 6.35 (2 H, br d, J

Notes
J . Org. Chem., Vol. 67, No. 9, 2002 3159
) 8.4 Hz), 6.49 (1 H, dq, J ) 16.0, 21 Hz), 6.81 (2 H, br d, J )
8.4 Hz); 13C NMR (125.7 MHz, CDCl3) δ 113.6, 118.2, 119.4 (q,
J ) 34.7 Hz), 123.0 (q, J ) 268.2 Hz), 128.1, 132.8, 135.9 (q, J
) 6.9 Hz), 137.7; HRMS calcd for C10H6F3N 197.0453, found
197.0450.
) 12.5 Hz, Z), 7.17 (73/100 H, dq, J ) 16.0, 2.0 Hz, E), 7.32
(27/100 H, dd, J ) 7.8, 5.0 Hz, Z), 7.35 (73/100 H, dd, J ) 7.8,
5.0 Hz, E), 7.75 (27/100 H, dt, J ) 7.8, 2.0 Hz, Z), 7.78 (73/100
H, dt, J ) 7.8, 2.0 Hz, E), 8.58 (27/100 H, dd, J ) 5.0, 2.0 Hz,
Z), 8.60 (27/100 H, d, J ) 2.0 Hz, Z), 8.62 (73/100 H, dd, J )
5.0, 2.0 Hz, E), 8.70 (73/100 H, d, J ) 2.0 Hz, E); 13C NMR (67.8
MHz, CDCl3) for E-isomer δ 117.9 (q, J ) 34.2 Hz), 123.0 (q, J
) 268.5 Hz), 123.1, 123.6, 133.8, 135.9 (q, J ) 6.1 Hz), 149.1,
150.9. The 1H NMR spectrum (in CDCl3) was identical with that
reported.5d
4-(3,3,3-Tr iflu or op r op -1-en yl)p yr id in e (3j): yellow oil; 1H
NMR (270 MHz, benzene-d6) δ 5.75 (1H, dq, J ) 16.2, 6.6 Hz),
6.38 (2H, br d, J ) 4.4 Hz), 6.52 (1H, dq, J ) 16.2, 2.2 Hz), 8.41
(2H, br d, J ) 4.4 Hz). Anal. Calcd for C8H6F3N: C, 55.50; H,
3.49; N, 8.09. Found: C, 55.21; H, 3.59; N, 8.02.
Meth yl 4-(3,3,3-tr iflu or op r op -1-en yl)ben zoa te (3f): color-
1
less crystals; mp 70-72 °C; H NMR (500 MHz, benzene-d6) δ
3.46 (3 × 5/100 H, s, Z), 3.49 (3 × 95/100 H, s, E), 5.26 (5/100 H,
dq, J ) 12.6, 9.3 Hz, Z), 5.73 (95/100 H, dq, J ) 16.7, 6.0 Hz, E),
6.16 (5/100 H, d, J ) 12.6 Hz, Z), 6.73 (95/100 H, dq, J ) 16.7,
2.1 Hz, E), 6.75 (2 × 95/100 H, br d, J ) 8.5 Hz, E), 7.07 (2 ×
5/100 H, br d, J ) 8.6 Hz, Z), 7.95 (2 × 95/100 H, br d, J ) 8.5
Hz, E), 7.97 (2 × 5/100 H, br d, J ) 8.6 Hz, Z); 13C NMR (67.8
MHz, CDCl3) for E-isomer δ 52.3, 118.2 (q, J ) 34.2 Hz), 123.2
(q, J ) 34.2 Hz), 127.5, 130.2, 131.4, 136.6 (q, J ) 6.1 Hz), 137.6,
166.4; HRMS calcd for C11H9F3O 230.0554, found 230.0552.
1-[4-(3,3,3-Tr iflu or op r op -1-en yl)-4-a cet ylb en zen e (3g):
(5,5,5-Tr iflu or op en ta -1,3-d ien yl)ben zen e (3k ): colorless
oil; 1H NMR (500 MHz, benzene-d6) d 5.16 (38/100 H, dq, J )
11.7, 8.8 Hz, Z), 5.34 (62/100 H, dq, J ) 15.1, 7.3 Hz, E), 5.99
(38/100 H, td, J ) 11.7, 1.0 Hz, Z), 6.18-6.25 (2 × 64/100 H, m,
E), 6.30 (38/100 H, br d, J ) 15.6 Hz, Z), 6.55-6.62 (62/100 H,
m, E), 6.99-7.14 (5 H, m, E + Z), 7.21 (38/100 H, ddq, J ) 15.6,
1
pale yellow oil; H NMR (500 MHz, benzene-d6) δ 2.03 (3 × 62/
100 H, s, Z), 2.05 (3 × 38/100 H, s, E), 5.29 (62/100 H, dq, J )
12.7, 9.3 Hz, Z), 5.78 (38/100 H, dq, J ) 16.1, 6.3 Hz, E), 6.18
(62/100 H, d, J ) 12.7 Hz, Z), 6.77 (38/100 H, dq, J ) 16.1, 2.4
Hz, E), 6.78 (2 × 38/100 H, br d, J ) 8.3 Hz, E), 7.07 (2 × 62/
100 H, br d, J ) 8.3 Hz, Z), 7.61 (2 × 38/100 H, br d, J ) 8.3 Hz,
E), 7.62 (2 × 62/100 H, J ) 8.3 Hz, Z); 13C NMR (125.7 MHz,
CDCl3) δ 26.6 (E and Z), 118.3 (q, J ) 34.6 Hz, E), 120.0 (q, J )
34.7 Hz, Z), 122.5 (q, J ) 270.5 Hz, Z), 123.2 (q, J ) 268.2 Hz,
E), 136.5 (q, J ) 6.9 Hz, E), 138.5 (q, J ) 6.9 Hz, Z), 197.2 (E),
197.4 (Z); HRMS calcd for C11H9F3O 214.0605, found 214.0606.
2-(3,3,3-Tr iflu or op r op -1-en yl)-1-m eth ylin d ole (3h ): color-
1
11.7, 1.2 Hz, Z); H NMR (500 MHz, CDCl3) δ 5.55 (38/100 H,
dqdd, J ) 11.7, 8.8, 1.2, 1.0 Hz, Z), 5.80 (62/100 H, dq, J ) 15.1,
6.8 Hz, E), 6.57 (38/100 H, ddd, J ) 12.2, 11.7, 1.2 Hz, Z), 6.76
(62/100 H, dd, J ) 15.1, 9.8 Hz, E), 6.78 (38/100 H, ddd, J )
15.1, 1.2, 1.0 Hz, Z), 6.82 (62/100 H, br d, J ) 15.1 Hz, E), 6.90
(62/100 H, ddq, J ) 15.1, 9.8, 2.0 Hz, E), 7.17 (38/100 H, ddqn,
J ) 15.1, 12.2, 1.2 Hz, Z), 7.31 (1 H, br t, J ) 6.8 Hz, E+Z), 7.36
(2 H, br t, J ) 6.8 Hz, E+Z), 7.44 (2 × 62/100 H, br d, J ) 6.8
Hz, E), 7.46 (2 × 38/100 H, br d, J ) 6.8 Hz, Z); 13C NMR (67.8
MHz, CDCl3) for E-isomer δ 118.3 (q, J ) 34.7 Hz), 123.5 (q, J
) 268.2 Hz), 124.9, 128.8, 128.9, 129.1, 135.8, 137.5 (q, J ) 6.9
Hz), 139.3. The 1H NMR spectral data (in benzene-d6 and in
CDCl3) were identical with those reported.5d,n
1
less crystals; mp 92-93 °C; H NMR (500 MHz, benzene-d6) δ
2.66 (3 H, s), 5.90 (1 H, dq, J ) 16.2, 6.6 Hz), 6.45 (1 H, br s),
6.84 (1 H, dq, J ) 16.2, 2.0 Hz), 6.87 (1 H, br d, J ) 7.8 Hz),
7.12 (1 H, br t, J ) 7.8 Hz), 7.17 (1 H, br t, J ) 7.8 Hz), 7.56 (1
H, br d, J ) 7.8 Hz); 13C NMR (125.7 MHz, CDCl3) δ 29.9, 102.7,
109.5, 116.3 (q, J ) 34.6 Hz), 120.4, 121.2, 123.3, 123.5 (q, J )
268.2 Hz), 126.3 (q, J ) 6.9 Hz), 127.3, 133.7, 138.7; HRMS calcd
for C12H10NF3 225.0766, found 225.0767.
3-P h en ylp r op en yl d ip h en ylp h osp h or osoa cet a t e (10):
1
colorless oil; H NMR (500 MHz, CDCl3) δ 3.18 (2 × 80/100 H,
d, J ) 7.3 Hz, Z), 3.24 (2 × 20/100 H, J ) 7.3 Hz, E), 3.54 (2 ×
20/100 H, J ) 15.6 Hz, E), 3.61 (2 × 80/100 H, J ) 15.6 Hz, Z),
5.00 (80/100 H, br q, J ) 7.3 Hz, Z), 5.37 (20/100 H, dt, J )
15.6, 7.3 Hz, E), 6.94-7.84 (16 H, m); HRMS calcd for C23H21O3P
336.1228, found 336.1234.
3-(3,3,3-Tr iflu or op r op -1-en yl)p yr id in e (3i): pale yellow
oil; 1H NMR (500 MHz, benzene-d6) δ 5.28 (27/100 H, dq, J )
12.7, 8.8 Hz, Z), 5.70 (73/100 H, dq, J ) 16.1, 6.8 Hz, E), 6.04
(27/100 H, d, J ) 12.7 Hz, Z), 6.56 (73/100 H, dd, J ) 7.8, 4.4
Hz, E), 6.61 (27/100 H, dd, J ) 7.8, 4.4 Hz, Z), 6.63 (73/100 H,
dq, J ) 16.1, 2.5 Hz, E), 6.81 (73/100 H, dt, J ) 7.8, 2.0 Hz, E),
7.29 (27/100 H, dt, J ) 7.8, 2.0 Hz, Z), 8.29 (73/100 H, d, J ) 2.0
Hz, E), 8.35 (27/100 H, dd, J ) 4.4, 2.0 Hz, Z), 8.36 (73/100 H,
dd, J ) 4.4, 2.0 Hz, E), 8.46 (27/100 H, d, J ) 2.0 Hz, Z); 1H
NMR (500 MHz, CDCl3) δ 5.92 (27/100 H, dq, J ) 12.5, 9.4 Hz,
Z), 6.30 (73/100 H, dq, J ) 16.0, 6.3 Hz, E), 6.92 (27/100 H, d, J
Su p p or tin g In for m a tion Ava ila ble: 1H NMR spectra for
3d -h and 10 and 13C NMR spectra for 3e-h . This material
is available free of charge via the Internet at http://pubs.acs.org.
J O0111311