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4.11–4.26 (m, 1H), 4.68 ppm (d, J=7.70 Hz, 1H); 13C NMR (CDCl3):
d=20.1 (s), 20.9 (s), 26.3 (s), 44.4 (s), 61.2 (s), 72.1 (q, J=29.8 Hz),
125.7 ppm (q, J=283.5 Hz); 19F NMR (CDCl3): d=À77.0 ppm (d, J=
8.50 Hz, 3F); HRMS (EI): m/z calcd for C7H13F3O2 [M]+: 186.0868;
found: 186.0875.
syn-2-Butyl-4,4,4-trifluorobutane-1,3-diol (syn-4ac)[8b]
Rf 0.18 (hexane–ethyl acetate=4:1); ½a27 =À21.18 (c=0.55, CHCl3,
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90% ee); IR (KBr): n˜ =3356 cmÀ1 (OH); H NMR (CDCl3): d=0.90 (t,
J=6.51 Hz, 4H), 1.19–1.45 (m, 6H), 1.48–1.61 (m, 1H), 1.98 (brs,
1H), 3.82 (d, J=5.00 Hz, 2H), 4.25 ppm (qd, J=7.93, 2.48 Hz, 1H);
13C NMR (CDCl3): d=14.0 (s), 22.9 (s), 24.4 (s), 29.9 (s), 40.8 (s), 63.7
(s), 72.0 (q, J=29.8 Hz), 125.6 ppm (q, J=283.1 Hz); 19F NMR
(CDCl3): d=À75.0 ppm (d, J=7.93 Hz, 3F); HRMS (CI): m/z calcd for
C8H16F3O2 [M+H]+: 201.1102; found: 201.1108.
syn-4,4-Difluoro-2-hexylbutane-1,3-diol (syn-4bd)
Rf 0.13 (CH2Cl2–ethyl acetate=10:1); ½a25 =À17.58 (c=0.72, CHCl3,
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77% ee); IR (KBr): n˜ =3356 cmÀ1 (OH); H NMR (CDCl3): d=0.87 (t,
J=6.51 Hz, 3H), 1.25–1.33 (m, 8H), 1.37–1.40 (m, 2H), 1.84 (brs,
1H), 2.70 (brs, 1H), 3.54 (brs, 1H), 3.72–3.83 (m, 2H), 3.92–4.03 (m,
1H), 5.80 ppm (td, J=55.98, 5.23 Hz, 1H); 13C NMR (CDCl3): d=14.2
(s), 22.7 (s), 24.9 (s), 27.6 (s), 29.6 (s), 31.8 (s), 40.7 (s), 63.6 (s), 73.1
(dd, J=24.5, 21.6 Hz), 115.9 ppm (t, J=242.9 Hz); 19F NMR (CDCl3):
d=À129.1 (ddd, J=290.02, 55.98, 14.95 Hz, 1F), À127.0 ppm (ddd,
J=290.02, 55.98, 7.13 Hz, 1F); HRMS (CI): m/z calcd for C10H21F2O2
[M+H]+: 211.1510; found: 210.1509.
anti-2-Butyl-4,4,4-trifluorobutane-1,3-diol (anti-4ac)[8b]
Rf 0.25 (hexane–ethyl acetate=4:1); ½a27 = +3.88 (c=0.73, CHCl3,
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97% ee); IR (KBr): n˜ =3318 cmÀ1 (OH); H NMR (CDCl3): d=0.92 (t,
J=7.18 Hz, 3H), 1.28–1.44 (m, 4H), 1.56–1.72 (m, 2H), 1.82 (oct, J=
3.41, 1H), 2.60 (brs, 1H), 3.77 (dd, J=10.80, 3.60 Hz, 1H), 4.01 (dd,
J=7.70, 3.60 Hz, 1H), 4.11 (d, J=11.20 Hz, 1H), 4.48 ppm (brs, 1H);
13C NMR (CDCl3): d=14.0 (s), 22.8 (s), 28.5 (s), 29.3 (s), 38.3 (s), 63.4
(s), 73.7 (q, J=30.1 Hz), 125.6 ppm (q, J=283.1 Hz); 19F NMR
(CDCl3): d=À76.8 ppm (d, J=7.70 Hz, 3F); HRMS (EI): m/z calcd for
C8H15F3O2 [M]+: 200.1024; found: 200.1027.
anti-4,4-Difluoro-2-hexylbutane-1,3-diol (anti-4bd)
Rf 0.19 (CH2Cl2–ethyl acetate=10:1); ½a24 =À3.78 (c=0.79, CHCl3,
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85% ee); IR (KBr): n˜ =3356 cmÀ1 (OH); H NMR (CDCl3): d=0.87 (t,
syn-4,4,4-Trifluoro-2-hexylbutane-1,3-diol (syn-4ad)
J=6.74 Hz, 3H), 1.21–1.38 (m, 8H), 1.42–1.54 (m, 2H), 1.78 (brs,
1H), 2.91 (brs, 1H), 3.68–3.98 (m, 4H), 5.86 ppm (td, J=56.10,
4.50 Hz, 1H); 13C NMR (CDCl3): d=14.1 (s), 22.7 (s), 27.1 (s), 28.3 (s),
29.4 (s), 31.8 (s), 39.4 (s), 63.1 (s), 73.9 (t, J=23.0 Hz), 116.2 ppm (t,
J=243.4 Hz); 19F NMR (CDCl3): d=À128.49 (ddd, J=287.17, 56.10,
12.45 Hz, 1F), À128.32 ppm (ddd, J=287.17, 56.10, 9.58 Hz, 1F);
HRMS (CI): m/z calcd for C10H21F2O2 [M+H]+: 211.1510; found:
211.1514.
Rf 0.13 (hexane–ethyl acetate=4:1); ½a27 =À15.78 (c=0.36, CHCl3,
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84% ee); IR (KBr): n˜ =3333 cmÀ1 (OH); H NMR (CDCl3): d=0.88 (t,
J=6.73 Hz, 3H), 1.18–1.33 (m, 10H), 1.34–1.42 (m, 2H), 1.48–1.57
(m, 1H), 1.99 (brs, 1H), 3.83 (d, J=5.80 Hz, 1H), 4.25 ppm (qd, J=
8.03, 2.15 Hz, 1H); 13C NMR (CDCl3): d=14.2 (s), 22.7 (s), 24.7 (s),
27.7 (s), 29.5 (s), 31.8 (s), 40.8 (s), 63.8 (s), 72.2 (q, J=30.1 Hz),
125.6 ppm (q, J=283.1 Hz); 19F NMR (CDCl3): d=À75.0 ppm (d, J=
8.03 Hz, 3F); HRMS (CI): m/z calcd for C10H20F3O2 [M+H]+:
229.1415; found: 229.1411.
Typical Procedure for the Preparation of 1,3-Dioxane 6
Benzaldehyde dimethyl acetal (52.5 mg, 0.345 mmol) and p-TsOH
monohydrate (9 mg, 0.051 mmol) were added to a solution of syn-
4aa (55.7 mg, 0.23 mmol) in CH2Cl2 (2.4 mL) at 08C. After the mix-
ture was stirred for 1 h at room temperature, it was quenched by
the addition of a saturated aqueous solution of Na2HCO3 (50 mL).
The organic materials were extracted with ethyl acetate (3
30 mL), dried over Na2SO4, filtered, and concentrated in vacuo. Pu-
rification by preparative TLC (ethyl acetate–hexane=1:7) gave
acetal 6 (58.5 mg, 78%).
anti-4,4,4-Trifluoro-2-hexylbutane-1,3-diol (anti-4ad)
Rf 0.25 (hexane–ethyl acetate=4:1); ½a27 = +4.08 (c=0.81, CHCl3,
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91% ee); IR (KBr): n˜ =3337 cmÀ1 (OH); H NMR (CDCl3): d=0.88 (t,
J=6.73 Hz, 3H), 1.22–1.43 (m, 8H), 1.53–1.68 (m, 2H), 1.82 (oct, J=
3.41, 1H), 2.64 (s, 1H), 3.76 (dd, J=11.25, 3.15 Hz, 1H), 4.01 (s, 1H),
4.11 (d, J=10.80 Hz, 1H), 4.50 ppm (s, 1H); 13C NMR (CDCl3): d=
14.2 (s), 22.7 (s), 27.1 (s), 28.8 (s), 29.4 (s), 31.8 (s), 38.4 (s), 63.5 (s),
73.7 (q, J=30.1 Hz), 125.6 ppm (q, J=283.4 Hz); 19F NMR (CDCl3):
d=À76.7 ppm (d, J=7.60 Hz, 3F); HRMS (CI): m/z calcd for
C10H20F3O2 [M+H]+: 229.1415; found: 229.1425.
(4S,5R)-5-Benzyl-2-phenyl-4-(trifluoromethyl)-1,3-dioxane
(syn-6)
syn-4,4,4-Trifluoro-2-isopropylbutane-1,3-diol (syn-4ae)
Rf 0.65 (hexane–ethyl acetate=7:1); ½a26 =À95.18 (c=1.00, CHCl3);
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m.p. 53.4–54.98C; 1H NMR (CDCl3): d=2.00–2.07 (m, 1H), 3.01 (d,
J=13.03 Hz, 1H), 3.21 (t, J=13.03 Hz, 1H), 3.82 (d, J=11.85 Hz,
1H), 4.02 (d, J=11.85 Hz, 1H), 4.54 (qd, J=7.18, 2.25 Hz, 1H), 5.63
(s, 1H), 7.21–7.34 (m, 5H), 7.38–7.59 ppm (m, 5H); 13C NMR (CDCl3):
d=30.6 (s), 35.5 (s), 68.3 (s), 78.1 (q, J=31.9 Hz), 102.7 (s), 123.5 (q,
J=282.5 Hz), 126.4 (s), 126.6 (s), 128.6 (s), 128.7 (s), 129.6 (s), 129.7
(s), 137.3 (s), 139.2 ppm (s); 19F NMR (CDCl3): d=À74.0 ppm (d, J=
7.18 Hz, 3F); HRMS (EI): m/z calcd for C18H17F3O2 [M]+: 322.1181;
found: 322.1181.
Rf 0.15 (hexane–ethyl acetate=4:1); ½a25 =À6.88 (c=0.26, CHCl3,
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92% ee); m.p. 81.5–83.08C (92% ee); IR (KBr): n˜ =3341 cmÀ1 (OH);
1H NMR (CDCl3): d=0.97 (d, J=6.51 Hz, 3H), 1.03 (d, J=6.51 Hz,
3H), 1.82–1.99 (m, 3H), 3.77–3.94 (m, 2H), 3.95–4.07 (m, 1H),
4.31 ppm (qd, J=8.10, 3.20 Hz, 1H); 13C NMR (CDCl3): d=20.7 (s),
22.3 (s), 26.0 (s), 47.5 (s), 61.9 (s), 71.3 (q, J=29.8 Hz), 126.0 ppm (q,
J=284.7 Hz); 19F NMR (CDCl3): d=À74.1 ppm (d, J=8.10 Hz, 3F);
HRMS (EI): m/z calcd for C7H13F3O2 [M]+: 186.0868; found:
186.0863.
(4R,5R)-5-Benzyl-2-phenyl-4-(trifluoromethyl)-1,3-dioxane
anti-4,4,4-Trifluoro-2-isopropylbutane-1,3-diol (anti-4ae)
(anti-6)
Rf 0.35 (hexane–ethyl acetate=4:1); ½a25 = +1.58 (c=0.16, CHCl3,
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90% ee); IR (KBr): n˜ =3314 cmÀ1 (OH); H NMR (CDCl3): d=1.02 (dd,
Rf 0.65 (hexane–ethyl acetate=7:1); ½a24 =À12.08 (c=1.00, CHCl3);
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J=11.44, 6.96 Hz, 6H), 1.52 (q, J=3.14, 1H), 2.07 (oct, J=6.73 Hz,
1H), 2.75 (brs, 1H), 3.93 (d, J=9.45 Hz, 1H), 4.06 (d, J=9.45, 1H),
m.p. 76.5–78.88C; H NMR (CDCl3): d=2.26 (dd, J=13.65, 10.77 Hz,
1H), 2.38–2.51 (m, 1H), 3.04 (d, J=13.65 Hz, 1H), 3.51 (t, J=
Chem. Asian J. 2015, 10, 2701 – 2707
2706
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