M. Kawasaki et al. / Tetrahedron: Asymmetry 14 (2003) 1529–1534
1533
The organic phase was washed with water, saturated
4.10. (S)-Phenyl 1-phenyl-3-butenyl ether (S)-8
sodium hydrogen carbonate, brine and dried over
sodium sulfate. After removal of the solvent, the
residue was chromatographed (silica gel, hexane–ethyl
acetate 5:1 (v/v)) to give (R)-5 (0.59 g, 66%, >99% e.e.)
as a white solid; mp 42.8–44.5°C; [h]2D7 +46.6 (c 1.0,
(S)-8 was prepared in 62% yield and 95% e.e. from
1
(R)-6 by the above method. H NMR spectral date of
this sample were identical with those of (R)-8.
4.11. (R)-3-Phenoxy-3-phenylpropanoic acid (R)-9
1
CHCl3) (lit.4 [h]D +51 (c 1, CHCl3) (R)); H NMR: l
7.87–7.90 (1H, m), 7.45–7.50 (1H, m), 6.96–7.03 (2H,
m), 4.56–4.64 (1H, m), 2.69 (2H, d, J=7.6), 1.53 (3H,
d, J=6.1); IR (CCl4): 1229, 1695 cm−1; MS (m/z) 162
(M+). HRMS calcd for C10H10O2 (M+), 162.0681.
Found: 162.0651.
A solution of NaIO4 (15.56 g, 72.75 mmol) in water
(330 ml) was treated with KMnO4 (0.23 g, 1.46 mmol),
K2CO3 (1.17 g, 8.47 mmol) and tert-butyl alcohol (85
ml). To the mixture, a solution of (R)-8 (1.78 g, 7.94
mmol) in tert-butyl alcohol (80 ml) was slowly added.
The resulting brown suspension was stirred for 3 h at
rt. A solution of KMnO4 (0.30 g, 1.90 mmol) in water
(20 ml) was added to the mixture to consume (R)-8
completely, and the resulting mixture was stirred for 1
h at ambient temperature. The mixture was treated with
ethylene glycol (3 ml), stirred for 2 h, and acidified to
pH 4 with 1 M HCl. The resulting brown solid was
filtrated with suction, and the filtrate was extracted
three times with ethyl acetate. The organic layer was
washed with brine, then dried over anhydrous sodium
sulfate and concentrated under reduced pressure. The
residue was chromatographed (silica gel, hexane–ethyl
acetate 1:2 (v/v)) to give (R)-9 (1.28 g, 67%) as a
4.7. (S)-2-Methylchroman-4-one (S)-5
(S)-5 was prepared from (S)-5 according procedure
described above in 89% yield and >99% e.e.; mp 44.0–
44.5°C (lit.7 39–40°C); [h]D241−48.1 (c 1.1, CHCl3) (lit.4
[h]D +51 (c 1, CHCl3) (R)); H NMR: l 7.87–7.89 (1H,
m), 7.46–7.49 (1H, m), 6.96–7.03 (2H, m), 4.57–4.63
(1H, m), 2.69 (2H, d, J=8.3), 1.52 (3H, d, J=6.4); IR
(CCl4): 1229, 1696 cm−1; MS (m/z) 162 (M+). HRMS
calcd for C10H10O2 (M+), 162.0681. Found: 162.0689.
4.8. Lipase-catalyzed transesterification of ( )-6 with
vinyl acetate
1
colorless viscous oil; H NMR: l 7.16–7.41 (7H, m),
6.85–6.91 (3H, m), 5.62 (1H, dd, J=9.2, J=4.3), 3.09
(1H, dd, J=16.0, J=9.2) 2.83 (1H, dd, J=20.1, J=
4.4); IR (CCl4): 1236, 1704 cm−1; MS (m/z) 242 (M+).
HRMS calcd for C15H14O3 (M+), 242.0943. Found:
242.0945.
Amano PS (20 g) was added to a solution of ( )-6 (5.00
g, 33.7 mmol) and vinyl acetate (11.60 g, 134.7 mmol)
in isooctane (300 ml). The mixture was stirred for 48 h
at 30°C. The reaction was quenched by filtration and
the filtrate was concentrated under reduced pressure.
The residue was chromatographed (silica gel, hexane–
ethyl acetate 99:1–9:1 (v/v)) to give (S)-6 (2.00 g, 40%,
>99% e.e.) as a colorless oil and the acetate (R)-7 (3.01
g, 47%, 92% e.e.) as a colorless oil. 6 M NaOH (5 ml)
was added to a solution of the (R)-7 (3.01 g, 15.8
mmol) in methanol (30 ml). The mixture was stirred for
6 h at rt. After removal of the solvent, the residue was
extracted with ethyl acetate. The organic layer was
washed with brine, then dried over Na2SO4 and concen-
trated under reduced pressure to give (R)-6. According
to the procedures described above, the crude alcohol
(R)-6 obtained here was again subjected to the lipase-
catalyzed transesterification, and the resultant ester (R)-
7 was again hydrolyzed with NaOH to give (R)-6 (1.10
4.12. (S)-3-Phenoxy-3-phenylpropanoic acid (S)-9
(S)-9 was prepared in 80% yield from (S)-8 by the
1
above method. H NMR spectral date of this sample
were identical with those of (R)-9.
4.13. (R)-2-Phenylchroman-4-one (R)-10
(R)-10 was prepared from (R)-9 according to the proce-
dure for preparation of (R)-5. Chromatography (silica
gel, hexane–ethyl acetate 5:1 (v/v)) of the crude product
and subsequent recrystallization from hexane afforded
(R)-10 (49%, 96% e.e.) as a white solid; [h]2D4 +61.6 (c
1.0, CHCl3) (lit.4 [h]D −67 (c 1, CHCl3) (S)); mp
1
77.8–79.0°C (lit.11 mp 74.5–75°C); H NMR: l 7.94–
g, 22% from ( )-6, >99% e.e.). H NMR spectral date
1
of (R)-6 and (S)-6 were identical with those of ( )-6.
7.95 (2H, m), 7.40–7.54 (6H, m), 7.06–7.09 (2H, m),
5.50 (1H, dd, J=13.3, J=2.8), 3.07–3.14 (1H, m) 2.88–
2.93 (1H, m); IR (CCl4): 1228, 1697 cm−1; MS (m/z)
224 (M+). HRMS calcd for C15H12O2 (M+), 224.0837.
Found: 224.0833.
4.9. (R)-Phenyl 1-phenyl-3-butenyl ether (R)-8
(R)-8 was prepared from (S)-6 and phenol using
triphenylphosphine and DIAD (diisopropyl azodicar-
boxylate) in 61% yield and 97% e.e. according to the
procedure for preparation of ( )-2. Chromatography
(silica gel, hexane–ethyl acetate 20:1 (v/v)) of the crude
4.14. (S)-2-Phenylchroman-4-one (S)-10
(S)-10 was prepared in 60% yield and 96% e.e. from
(S)-9 according to the procedure for preparation of
(R)-5; [h]2D6 −58.6 (c 1.0, CHCl3) (lit.4 [h]D −67 (c 1,
1
product afforded (R)-8 as a colorless oil; H NMR: l
7.16–7.37 (7H, m), 6.83–6.88 (3H, m), 5.81–5.92 (1H,
m), 5.06–5.16 (4H, m), 2.73–2.80 (1H, m), 2.55–2.62
(1H, m); IR (neat): 1238, 1642 cm−1; MS (m/z) 224
(M+). HRMS calcd for C16H16O (M+), 224.1201.
Found: 224.1239.
1
CHCl3) (S)); mp 77.4–78.2°C (lit.11 mp 75–77°C); H
NMR: l 7.93–7.96 (2H, m), 7.38–7.54 (6H, m), 7.05–
7.08 (2H, m), 5.50 (1H, dd, J=13.4, J=2.9), 3.07–3.14
(1H, m) 2.88–2.93 (1H, m); IR (CCl4): 1228, 1697 cm−1;