K. Tamura et al. / Journal of Fluorine Chemistry 126 (2005) 918–930
927
19F NMR (CDCl3): d 123.7 (ddd, J = 17.22, 56.75,
284.7 Hz), 120.6 (ddd, J = 14.68, 56.75, 287.4 Hz). IR
(neat): g 1699 (C O) cmꢀ1. Anal. Calcd for C14H15NO4F2:
C, 56.19; H, 5.05; N, 4.68. Found: C, 55.87; H, 5.30; N, 4.66.
NMR (CDCl3): d 72.6 (d, J = 9.60 Hz). IR (neat): g 1742
(C O) cmꢀ1. Anal. Calcd for C15H19O2F3: C, 62.49; H,
6.64. Found: C, 62.26; H, 6.38.
4.17. Benzyl 3-(trifluoromethyl)-4-methylpentanoate
(1c)
4.14. Ethyl 3-(trifluoromethyl)-4-methylpentanoate (1b)
To a solution of corresponding nitro compound 9a
(7.00 g, 27.2 mmol) and tributyltin hydride (7.32 ml,
27.2 mmol) in anhydrous benzene (20 ml) was added
a,a0-azobis(isobutyronitrile) (0.89 g, 5.44 mmol) or ben-
zoyl peroxide (1.32 g, 5.44 mmol) under an atmosphere of
argon. After 6 h refluxed, the reaction mixture was
evaporated and the residue was purified by silica gel
column chromatography (hexane/ethyl acetate, 10:1) to give
the desired denitro compound 1b as a colorless liquid
Yield 72%. 1H NMR (CDCl3): d 0.88 (3H, d,
J = 6.60 Hz), 0.90 (3H, d, J = 7.20 Hz), 2.02 (1H, dsept,
J = 3.60, 6.90 Hz), 2.38 (1H, dd, J = 6.00, 16.50 Hz), 2.49
(1H, dd, J = 6.60, 16.65 Hz), 2.68 (1H, qq, J = 3.30,
6.45 Hz), 5.07 (2H, s), 7.25–7.33 (Ar–H, m). 13C NMR
(CDCl3): d 18.47 (q, J = 1.43 Hz), 20.27, 26.80 (q,
J = 1.66 Hz), 44.63 (q, J = 24.60 Hz), 66.80, 127.63 (q,
J = 280.60 Hz), 128.11, 128.18, 128.38, 135.24, 171.18. 19
F
NMR (CDCl3): d 69.3 (d, J = 9.60 Hz). IR (neat): g 1742
(C O) cmꢀ1. Anal. Calcd for C14H17O2F3: C, 61.31; H,
6.25. Found: C, 61.56; H, 5.94.
1
(3.75 g, yield 65%). H NMR (CDCl3): d 0.97 (6H, dd,
J = 7.20, 8.10 Hz), 1.25 (3H, t, J = 7.20 Hz), 2.09 (1H,
dsept, J = 3.60, 6.75 Hz), 2.39 (1H, dd, J = 6.00, 16.50 Hz),
2.49 (1H, dd, J = 6.60, 16.50 Hz), 2.72 (1H, qq, J = 3.60,
6.60 Hz), 4.15 (2H, q, J = 7.20 Hz). 13C NMR (CDCl3): d
14.02, 18.40 (q, J = 1.43 Hz), 20.26, 26.78 (q, J = 1.74 Hz),
29.82 (q, J = 2.87 Hz), 44.60 (q, J = 24.92 Hz), 60.89,
127.67 (q, J = 280.63 Hz), 171.30. 19F NMR (CDCl3): d
69.3 (d, J = 10.15 Hz). IR (neat): g 1741 (C O) cmꢀ1. Anal.
Calcd for C9H15O2F3: C, 50.94; H, 7.12. Found: C, 50.83; H,
6.77.
4.18. Benzyl 3-(trifluoromethyl)-4,4-dimethylpentanoate
(1d)
1
Yield 68%. H NMR (CDCl3): d 1.05 (9H, s), 2.57 (1H,
dd, J = 5.40, 9.15 Hz), 2.61 (1H, dd, J = 6.30, 16.50 Hz),
2.77 (1H, dquint, J = 5.10, 6.45 Hz), 5.18 (2H, s), 7.35–7.41
(Ar–H, m). 13C NMR (CDCl3): d 14.06, 28.00 (q,
J = 1.96 Hz), 31.15 (q, J = 3.40 Hz), 48.22 (q,
J = 23.77 Hz), 66.80, 127.91 (q, J = 282.03 Hz), 128.06,
128.13, 128.36, 135.30, 171.57. 19F NMR (CDCl3): d 65.2
(d, J = 10.16 Hz). IR (neat): g 1743 (C O) cmꢀ1. Anal.
Calcd for C15H19O2F3: C, 62.49; H, 6.64. Found: C, 62.37;
H, 6.46.
4.15. Benzyl 3-(difluoromethyl)-4-methylpentanoate
(1k)
Yield 68%. 1H NMR (CDCl3): d 0.94 (3H, d,
J = 7.20 Hz), 0.97 (3H, d, J = 7.80 Hz), 1.92 (1H, dquint,
J = 1.80. 5.10 Hz), 2.36 (1H, dsept, J = 2.40, 5.70 Hz), 2.40
(1H, dd, J = 5.70, 16.50 Hz), 2.56 (1H, dd, J = 6.30,
16.05 Hz), 5.13 (2H, s), 5.87 (1H, dt, J = 3.30, 56.10 Hz),
7.26–7.37 (Ar–H, m). 13C NMR (CDCl3): d 19.29, 19.86,
27.10 (t, J = 3.17 Hz), 29.64 (t, J = 5.13 Hz), 44.48 (t,
J = 18.04 Hz), 66.49, 117.35 (t, J = 241.64 Hz), 128.01,
128.04, 128.31, 135.48, 171.94. 19F NMR (CDCl3): d 125.3
(ddd, J = 20.89, 56.89, 282.3 Hz), 120.9 (ddd, J = 11.86,
56.04, 282.62 Hz). IR (neat): g 1734 (C O) cmꢀ1. Anal.
Calcd for C14H19O2F2: C, 65.61; H, 7.08. Found: C, 65.62;
H, 7.06.
4.19. Benzyl 3-(trifluoromethyl)-4-pentenoate (1e)
1
Yield 75%. H NMR (CDCl3): d 2.57 (1H, dd, J = 9.90,
15.90 Hz), 2.79 (1H, dd, J = 4.20, 15.90 Hz), 3.37 (1H,
dsext, J = 4.50, 9.00 Hz), 5.13 (2H, s), 5.29 (1H, s), 5.33
(1H, d, J = 4.80 Hz), 5.70 (1H, td, J = 8.40, 18.45 Hz), 7.30–
7.41 (Ar–H, m). 13C NMR (CDCl3): d 33.27 (q,
J = 2.57 Hz), 44.44 (q, J = 28.07 Hz), 66.80, 121.58,
125.29 (q, J = 278.9 Hz), 128.38, 128.25, 128.19, 129.67
(q, J = 2.57 Hz), 135.13, 169.65. 19F NMR (CDCl3): d 72.7
(d, J = 8.75 Hz). IR (neat): g 1742 (C O) cmꢀ1. Anal. Calcd
for C13H13O2F3: C, 60.46; H, 5.07. Found: C, 60.87; H, 4.87.
4.16. Benzyl 3-(trifluoromethyl)heptanoate (1a)
4.20. Ethyl 4,4,4-trifluoro-3-(4-methoxy-phenyl)-
butanoate (1f)
The transesterification of oxazolidone derivatives (11)
carried out the same procedure of Evans et al. [16] Yield
1
67%. H NMR (CDCl3): d 0.80 (3H, t, J = 7.20 Hz), 1.18–
Yield 75%. 1H NMR (CDCl3): d 1.06 (3H, t, J = 7.20 Hz),
2.77 (1H, dd, J = 9.90, 16.20 Hz), 2.92 (1H, dd, J = 5.10,
16.20 Hz), 3.71 (3H, s), 3.79 (1H, dquint, J = 5.10, 9.30 Hz),
3.98 (2H, ddq, J = 8.10, 10.80, 11.70 Hz), 6.81 (2H, d,
J = 8.70 Hz), 7.17 (2H, d, J = 8.10 Hz). 13C NMR (CDCl3):
d 13.96, 34.47, 45.27 (q, J = 27.70 Hz), 55.08, 60.86,
113.84, 125.40, 126.23 (q, J = 279.1 Hz), 129.76, 159.32,
1.36 (6H, m), 2.34 (1H, dd, J = 7.50, 16.35 Hz), 2.57 (1H,
dd, J = 5.70, 16.20 Hz), 2.63 (1H, dsept, J = 16.20,
2.10 Hz), 5.07 (2H, s), 7.31–7.25 (Ar–H, m). 13C NMR
(CDCl3):
J = 2.87 Hz), 36.65 (q, J = 26.04 Hz), 66.73, 127.56 (q,
J = 279.16 Hz), 128.15, 128.20, 128.38, 135.25, 170.71. 19
d 13.77, 22.55, 27.97, 28.60, 33.33 (q,
F