A R T I C L E S
Spraul et al.
chromatography on silica gel hexane/ethyl acetate (85:15) to afford
257 mg (65%) of the dimer of 7 as a clear oil. H NMR (500 MHz,
4.1.14. (4-(Trifluorovinyloxy)phenyl)trimethylstannane (9). To a
flame dried two-neck flask, 1 (3 g, 11.85 mmol) and 30 mL of dry
Et2O were charged. The reaction mixture was cooled to -78 °C, and
t-BuLi (1.5 M in pentane, 8.3 mL, 12.39 mmol) was added dropwise
via syringe. After complete addition, the reaction was maintained at
-78 °C for 1 h, and Me3SnCl (2.35 g, 11.85 mmol) in ether (20 mL)
was added. The reaction was allowed to warm and stir for 4 h at room
temperature. Water was added to quench the reaction, and the organic
layer was extracted into ether, dried with MgSO4, concentrated by rotary
evaporation, and purified by column chromatography on silica gel
hexane/ethyl acetate (85:15) to afford 3.39 mg (85%) of 9 as a clear
oil. GC/MS (EI) m/z (% relative intensity): 135 (15), 226 (14), 293
(12), 323 (100). FTIR (KBr, cm-1): 3022 (m), 2983 (m), 2923 (m),
1831 (m), 1579 (s), 1492 (s) 1388 (w), 1284 (s), 1175 (s), 1072 (m),
766 (s). 1H NMR (500 MHz, CDCl3, δ): 0.33 (s, 9H), 7.11 (d, J ) 10
Hz, 2H), 7.51 (d, J ) 10 Hz, 2H). 19F NMR (470 MHz, CDCl3, δ):
-133.78 (dd, 1F), -126.92 (dd 1F), -119.98 (dd, 1F) (Jgem ) 97 Hz,
Jcis ) 58 Hz, Jtrans ) 111 Hz). 13C NMR (125 MHz, CDCl3, δ): -9.5,
115.6, 133.7 (ddd, J ) 42 Hz, 38 Hz, 263 Hz), 137.4, 147.1 (ddd, J )
59 Hz, 276 Hz, 275 Hz), 155.8. HRMS Calculated (Found) for C11H13F3-
OSn 337.9940 (337.9938).
1
CDCl3, δ): 7.23 (d, J ) 10 Hz, 1H), 7.34 (d, J ) 9 Hz, 1H), 7.89-
7.94 (m, 2H), 9.97 (s, 1H), 9.99 (s, 1H). 19F NMR (470 MHz, CDCl3,
δ) -132.08, -131.66, -130.09, -129.53, -129.49, -129.00, -128.24,
-127.76, -127.51, -127.03. 13C NMR (125 MHz, CDCl3, δ): 118.3,
118.4, 131.8, 131.9, 133.6, 133.7, 156.8, 190.5. HRMS Calculated
(Found) for C18H10F6O4 404.0483 (404.0481).
4.1.10. 4-(Trifluorovinyloxy)benzyl Alcohol (Precursor to 8). In
a two-neck flask, equipped with a nitrogen inlet adapter and magnetic
stir bar, was added 7 (2.20 g, 11 mmol) dissolved in dry MeOH (20
mL). The solution was cooled to 0 °C, and NaBH4 (413 mg, 11 mmol)
was added in four portions at 15 min intervals. After stirring for 3 h,
the reaction was allowed to warm to room temperature and stirred for
an additional 15 h. The reaction mixture was then quenched with water,
and the organic layer was extracted into diethyl ether, dried with
MgSO4, and concentrated by rotary evaporation to afford 1.84 g (82%)
of 4-(trifluorovinyloxy)benzyl alcohol as a colorless oil. 1H NMR (500
MHz, CDCl3, δ): 2.63 (s, 1H), 4.48 (s, 2H), 7.06 (d, J ) 10 Hz, 2H),
7.39 (d, J ) 10 Hz, 2H). 19F NMR (470 MHz, CDCl3, δ): -134.2 (dd,
1F), -126.30 (dd), -119.41 (dd, 1F) (Jgem ) 99 Hz, Jcis ) 56 Hz, Jtrans
) 108 Hz). 13C NMR (125 MHz, CDCl3, δ): 115.9, 128.7, 133.8 (ddd,
J ) 41 Hz, 39 Hz, 262 Hz), 137.6, 147.0 (ddd, J ) 60 Hz, 277 Hz,
272 Hz), 154.5.
4.1.15. 1,2-Bis(4-trimethylstannylphenoxy)hexafluorocyclobutane.
To a flame dried two-neck flask, bis(4-bromophenoxyl)hexafluorocy-
clobutane (200 mg, 40 mmol) in dry Et2O (5 mL) was added and cooled
to -78 °C. At that temperature, t-BuLi (1.5 M in pentane, 0.58 mL,
0.87 mmol) was added dropwise via syringe. After the reaction stirred
for 1 h, Me3SnCl (165 mg, 0.83 mmol) in ether (3 mL) was added and
the reaction mixture was allowed to warm and stir for 4 h at room
temperature. The reaction mixture was quenched with water, and the
product was extracted into ether. The organic layer was concentrated
by rotary evaporation, and the product was purified by column
chromatography on silica gel treated with NEt3 to afford 108 mg (80%)
of the dimer of 9 as a white crystalline solid. Mp 158 °C. GC/MS (EI)
m/z (% relative intensity): 165(100), 306(38), 321(67), 477(33),
497(35). 1H NMR (500 MHz, CDCl3, δ): 0.031 (s, 9 H), 7.11 (d, J )
8 Hz, 1H), 7.19 (d, J ) 7 Hz, 1H), 7.45 (d, J ) 10 Hz, 1H), 7.47 (d,
J ) 11 Hz, 1H). 19F NMR (470 MHz, CDCl3, δ): -131.47, -130.87,
-130.56-130.09, -129.92, -128.67, -128.16, -127.7. 13C NMR (125
MHz, CDCl3, δ): -10.7, 115.6, 118.3, 129.7, 129.9, 137.0, 137.2, 138.6,
138.9, 152.9, 153.0. HRMS Calculated (Found) for C21H23F6O2Sn2
660.9646 (660.9657).
4.1.11. 4-Bromomethyl(trifluorovinyloxy)benzene (Immediate
Precursor to 8). In a two-neck 50 mL flask equipped with a nitrogen
inlet adapter and magnetic stir bar, 4-(trifluorovinyloxy)benzyl alcohol
(1.83 g, 8.95 mmol) was diluted in CH2Cl2 (12 mL) and cooled to 0
°C. PBr3 (2.42 g, 8.95 mmol) was added dropwise to the reaction
mixture at 0 °C. After complete addition the reaction was stirred at
room temperature for 3 h. The organic layer was diluted with CH2Cl2
and washed several times with water. The organic layer was dried,
concentrated by rotary evaporation, and purified by column chroma-
tography on silica gel hexane/ethyl acetate (95:5) to afford 1.53 g (64%)
of 4-bromomethyl(trifluorovinyloxy)benzene as a colorless oil. 1H NMR
(500 MHz, CDCl3, δ): 4.47 (s, 1H), 7.05 (d, J ) 8 Hz, 1H), 7.38 (d,
J ) 8, 1H Hz). 19F NMR (470 MHz CDCl3, δ): -134.24 (dd, 1H),
-126.34 (dd, 1H), -119.46 (dd, 1H) (Jgem ) 103 Hz, Jcis ) 56 Hz,
Jtrans ) 117 Hz). 13C NMR (125 MHZ, CDCl3, δ): 64.3, 115.9, 128.7,
133.8 (ddd, J ) 44 Hz, 39 Hz, 266 Hz), 137.6, 144.6, 145.1, 146.7,
147.2, 148.9, 149.4 (ddd, J ) 61 Hz, 280 Hz, 276 Hz), 154.5.
4.1.12. Diethyl(4-(trifluorovinyloxy)phenyl)methylphosphonate
(8). In a one-neck flask, 4-bromomethyl(trifluorovinyloxy)benzene (770
mg, 2.88 mmol) and P(OEt)3 (527 mg, 3.17 mmol) were combined
and heated at 80 °C for 12 h under nitrogen. Excess P(OEt)3 was
removed by vacuum distillation to afford 924 mg (99%) of 8 as a clear
4.1.16. 4-Vinyl(trifluorovinyloxy)benzene (10). To a three-neck
flask, 1 (316 mg, 1.25 mmol) and DME (5 mL) were dissolved,
degassed with N2, and stirred for 20 min after which Pd(PPh3)4 (14
mg, 0.012 mmol) was added. The solution was degassed again and
stirred under N2 for 10 min. K2CO3 (172 mg, 1.25 mmol) was added
followed by water (3 mL) and 2,4,6-trivinylcyclotriboroxane pyridine
complex (301 mg, 1.25 mmol) prepared according to a published
procedure.21 The reaction was heated and stirred at 85 °C for 20 h.
The solvent was then removed under vacuum, and the product was
purified by column chromatography on silica hexane/ethyl acetate (95:
5) to afford 185 mg (74%) of 10 as a clear oil. FTIR (KBr, cm-1):
1831 (w), 1601 (w), 1503 (m), 1312 (m), 1269 (s),1186 (m), 1181
1
oil. H NMR (500 MHz, CDCl3, δ): 1.22 (t, 6H, J ) 7 Hz), 3.07 (d,
2H, J ) 20 Hz), 3.99 (q, 4H, J ) 3 Hz), 7.01 (d, 2H, J ) 5 Hz), 7.26
(d, 2H J ) 9 Hz). 19F NMR (470 MHz, CDCl3, δ): -134.25 (dd, 1F),
-126.33 (dd, 1F), -119.46 (dd, 1F) (Jgem ) 94 Hz, Jcis ) 57 Hz, Jtrans
) 109 Hz). 13C NMR (125 MHz, CDCl3, δ): 16.3, 34.6 62.3, 116.3,
130.9, 133. 6 (ddd, J ) 45 Hz, 40 Hz, 260 Hz), 134.6, 144.5, 147.2
(ddd, J ) 64 Hz, 279 Hz, 271 Hz), 154.9. HRMS Calculated (Found)
for C13H16F3O4P 324.0738 (324.0730).
1
(m), 1142 (s). H NMR (300 MHz, CDCl3, δ): 5.25 (d, J ) 11 Hz,
1H), 5.69 (d, J ) 18 Hz, 1H), 6.67 (dd J ) 11 Hz, 17 Hz, 1H), 7.08
(d, J ) 8 Hz, 2H), 7.42 (d, J ) 6 Hz, 2H). 19F NMR (470 MHz, CDCl3,
δ): -133.92 (dd, 1F), -126.72 (dd, 1F), -119.77 (dd, 1F) (Jgem ) 94
Hz, Jcis ) 56 Hz, Jtrans ) 108 Hz). 13C NMR (125 MHz, CDCl3, δ):
127.8, 133.5 (ddd, J ) 40 Hz, 41 Hz, 262 Hz), 134.6, 135.6, 147.0
(ddd, J ) 61 Hz, 277 Hz, 270 Hz), 154.7. HRMS Calculated (Found)
for C10H7O1F3 200.0449 (200.0446).
4.1.13. 1,2-Bis(4-diethyl(methylphosphonate)phenoxy)hexafluoro-
cyclobutane. Diethyl (4-(trifluorovinyloxy)phenyl)methylphosphonate
(8) (205 mg, 632 mmol) was heated in a single-neck round-bottom
flask at 150 °C for 2 days to afford 205 mg (100%) of the dimer of 8
as a viscous yellow oil. GC/MS (EI) m/z (% relative intensity): 90
1
(80), 107 (80), 124 (45), 187 (100), 324 (30). H NMR (500 MHz,
CDCl3, δ): 1.18-1.28 (m, 12H), 3.07 (d, J ) 5 Hz, 2H), 3.10 (d, J )
5 Hz, 2H), 3.94-4.03 (m, 8H), 7.04 (d, J ) 8 Hz, 2H), 7.12 (d, J )
6 Hz, 2H), 7.23-7.28 (m, 4H). 19F NMR (470 MHz, CDCl3, δ):
-131.30, -130.75, -130.63, -130.28, -130.12, -129.64, -128.68,
-128.36, -128.20, -127.89. 13C NMR (125 MHz, CDCl3, δ): 16.25,
32.06, 62.18, 115.98, 118.2, 128.40, 128.67, 131.00, 151.46.
4.1.17. 1,2-Bis(4-vinylphenoxy)hexafluorocyclobutane. In a two-
neck flask, bis(4-bromophenoxyl)hexafluorocyclobutane (200 mg, 0.40
mmol) and DME (5 mL) were added and degassed with 15 cycles of
vacuum and N2. The solution was allowed to stir under N2 for 20 min
after which Pd(PPh3)4 (9 mg, 0.008 mmol) was added and the solution
9
7062 J. AM. CHEM. SOC. VOL. 128, NO. 21, 2006