A. Maly et al. / Tetrahedron: Asymmetry 14 (2003) 1019–1024
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3.2.5. Diethyl 1,2-dihydroxy-2-(p-chlorophenyl)ethane-
phosphonate. 73% yield; 31P NMR (CDCl3), l: 23.9
Hz, OCH2CH3); 16.37 (d, J=5.7 Hz, OCH2CH3); 62.69
(d, J=7.3 Hz, OCH2CH3); 63.47 (d, J=6.8 Hz,
OCH2CH3); 72.06 (d, J=158.2 Hz, HCP); 72.24 (d,
J=3.6 Hz, PhCH); 127.31, 186.64, 129.07 (aromatic
ring); 140.93 (d, J=12.0 Hz, Cipso).
1
(threo) and 24.1 (erythro); H NMR (CDCl3), l: 1.10
(t, J=6.9 Hz, 6H, OCH2CH3, erythro); 1.18–1.31 (m,
6H, OCH2CH3, threo); 3.64 (bs, 1H, OH); 3.82–3.98
(m, 2H, OH, Ha); 4.06 (qq, J=6.8 Hz, OCH2CH3);
4.90–5.20 (m, 1H, Hb); 7.2–7.34 (m, 4H, aromatic pro-
tons); 13C NMR (l): 16.05 (d, J=6.0 Hz, OCH2CH3,
erythro); 16.33 (d, J=5.3 Hz, OCH2CH3, threo); 63.24
(d, J=7.4 Hz, OCH2CH3, erythro); 64.16 (d, J=6.9
Hz, OCH2CH3, threo); 72.30 (d, J=159.0 Hz, HCP,
threo); 72.51 (d, J=156.4 Hz, HCP, erythro); 72.23 (d,
J=1.1 Hz, PhCH, threo); 74.37 (d, J=1.1 Hz, PhCH,
erytho); 128.74, 128.84, 129.09, 129.16, 138.17 (aro-
matic ring); 138.54 (d, J=13.5 Hz, Cipso, threo); elemen-
tal analysis was not done because of the instability of
the compound.
3.3.2. Diethyl (1S,2S)-dihydroxy-2-(p-methylphenyl)-
ethanephosphonate. 31P NMR (CDCl3), l: 24.1; 1H
NMR (CDCl3), l: 1.19 and 1.25 (t, J=7.0 Hz, 3H
each, OCH2CH3); 2.26 (s, 3H, CH3); 3.94 (dd, J=3.0/
8.6 Hz, 1H, Ha); 4.00 (qq, J=7.0 Hz, 4H, OCH2CH3);
4.10 (bs, 1H, OH); 5.03 (bs, 1H, Hb); 7.07–7.25 (m, 4H,
aromatic protons); 13C NMR (l): 16.31 and 16.57 (d,
J=5.6 Hz, OCH2CH3); 21.09 (s, CH3); 62.68 (d, J=7.2
Hz, OCH2CH3); 63.41 (d, J=6.8 Hz, OCH2CH3); 72.10
(d, J=157.8 Hz, HCP); 72.16 (d, J=3.6 Hz, PhCH);
126.44, 128.93, 137.47 (aromatic ring); 137.90 (d, J=9.0
Hz, Cipso).
3.2.6. Diethyl 1,2-dihydroxy-2-(p-bromophenyl)ethane-
phosphonate. 23% yield; 31P NMR (CDCl3), l: 23.9
3.3.3. Diethyl (1R,2R)-dihydroxy-2-(o-methylphenyl)-
ethanephosphonate. 31P NMR (CDCl3), l: 24.1; 1H
NMR (CDCl3), l: 1.19–1.41 (m, J=7.0 Hz, 6H,
OCH2CH3); 2.26 (s, 3H, CH3); 3.47 (bs, 1H, OH); 3.97
(dd, J=2.4/7.2 Hz, 1.5H, Ha); 4.01–4.26 (m, 6.5H,
OCH2CH3, OH, Ha); 5.08 (m, 1H, Hb); 7.21–7.41 (m,
4H, aromatic protons); 13C NMR (l): 16.35 (d, J=5.9
Hz, OCH2CH3); 18.99 (s, CH3); 62.57 (d, J=7.4 Hz,
OCH2CH3); 63.60 (d, J=6.6 Hz, OCH2CH3); 68.29 (d,
J=3.4 Hz, PhCH); 70.25 (d, J=158.7 Hz, HCP);
125.93, 127.66, 129.93, 130.38 (aromatic ring); 137.96
(d, J=12.0 Hz, Cipso).
1
(threo) and 24.0 (erythro); H NMR (CDCl3), l: 1.06
(t, J=7.0 Hz, 6H, OCH2CH3, erythro); 1.11–1.27 (m,
6H, OCH2CH3, threo); 3.66 (bs, 1H, OH); 3.37–4.12
(bm, 4H, OCH2, Ha); 4.90 (d, J=5.5 Hz, Hb, erythro);
4.94–4.98 (m, 1H, Hb, threo); 7.20–7.40 (m, 4H, aro-
matic protons); 13C NMR (l): 15.99 (d, J=6.2 Hz,
OCH2CH3, erythro); 16.26 (d, J=3.0 Hz, OCH2CH3,
threo); 62.50 (d, J=6.9 Hz, OCH2CH3, erythro); 63.53
(d, J=7.4 Hz, OCH2CH3, threo); 72.01 (d, J=158.4
Hz, HCP, threo); 72.21 (d, J=155.6 Hz, HCP, ery-
thro); 73.94 (d, J=1.1 Hz, PhCH); 121.54, 121.61,
128.36, 131.11, 131.23 (aromatic ring); 140.62 (d, J=9.0
Hz, Cipso, threo); 141.01 (d, J=10.5 Hz, Cipso, threo);
elemental analysis was not done because of the instabil-
ity of the compound.
3.3.4. Diethyl (1R,2R)-dihydroxy-2-(m-methylphenyl)-
ethanephosphonate. 31P NMR (CDCl3), l: 24.1 1H
NMR (CDCl3), l: 1.23 and 1.27 (t, J=7.1 Hz, 3H
each, OCH2CH3); 2.28 (s, 3H, CH3); 3.90 (dd, J=3.2/
9.0 Hz, 1H, Ha); 4.00 (qq, J=7.1 Hz, 4H, OCH2). 4.10
(bs, 1H, OH); 4.96 (dd, J=3.4/17.5 Hz, Hb); 7.19–7.41
(m, 4H, aromatic protons); 13C NMR (l): 16.38 (d,
J=5.1 Hz, OCH2CH3); 16.41 (d, J=5.8 Hz,
OCH2CH3); 21.46 (s, CH3, threo); 62.62 (d, J=7.1 Hz,
OCH2CH3); 63.58 (d, J=6.7 Hz, OCH2CH3); 71.97 (d,
J=158.0 Hz, HCP); 72.07 (d, J=2.5 Hz, PhCH);
123.46, 127.02, 128.25, (aromatic ring); 139.82 (d, J=
11.8 Hz, Cipso).
3.3. Asymmetric dihydroxylation of vinylphosphonates
3-synthesis of diethyl erythro-1,2-dihydroxyethanephos-
phonates 2a
A solution of the reagent was prepared by mixing 5 mL
of t-butanol, 5 mL of water, 1.4 g appropriate AD-mix
and 0.95 g of methanesulphonate. This solution was
cooled to 0–5°C in water-ice bath and 1 mmol of
vinylphosphonate 3 was added, bath was removed and
the mixture allowed to reach room temperature. Then
1.5 g of sodium sulphite was added and stirring contin-
ued for additional 30–60 min. Product was extracted
with four portions (10 mL) of ethyl acetate, organic
layer was washed with 2 M potassium hydroxide solu-
tion (2×10 mL) and the organic layer dried over anhy-
drous magnesium sulphate. Products were purified by
means of planar rotary chromatography using mixtures
of ethyl acetate–dichloromethane–methanol (3:2:1) or
ethyl acetate–chloroform–methanol (3:2:1).
3.3.5. Diethyl (1S,2S)-dihydroxy-2-(p-chlorophenyl)-
ethanephosphonate. 31P NMR (CDCl3), l: 23.8 1H
NMR (CDCl3), l: 1.18 and 1.23 (t, J=7.1 Hz, 3H
each, OCH2CH3); 2.35 (bs, 1H, OH); 3.90 (dd, J=3.4/
0.2 Hz, 1H, Ha); 4.00 (qq, J=7.1 Hz, OCH2CH3); 4.96
(dd, J=3.7/9.2 Hz, 1H, Hb); 7.19–7.30 (m, 4H, aro-
matic protons); 13C NMR (l): 16.32 and 16.39 (d,
J=5.3 Hz, OCH2CH3); 62.87 (d, J=7.5 Hz,
OCH2CH3); 63.45 (d, J=6.8 Hz, OCH2CH3); 71.76 (d,
J=1.1 Hz, PhCH); 72.07 (d, J=157.5 Hz, HCP);
127.97, 128.36, 133.53 (aromatic ring); 138.69 (d, J=
12.0 Hz, Cipso).
3.3.1. Diethyl (1S,2S)-dihydroxy-2-phenylethanephos-
phonate and diethyl (1R,2R)-dihydroxy-2-phenylethane-
phosphonate. 31P NMR (CDCl3), l: 24.0; 1H NMR
(CDCl3), l: 1.17–1.24 (m, 6H, OCH2CH3); 1.88 (bs,
1H, OH); 3.95 (dd, J=2.7/8.3 Hz, Ha); 4.0 (qq, J=7.2
Hz, 4H, OCH2CH3); 5.03 (bs, 1H, Hb); 7.19–7.36 (m,
5H, aromatic protons); 13C NMR (l): 16.33 (d, J=5.5
3.3.6. Diethyl (1S,2S)-dihydroxy-2-(p-bromophenyl)-
ethanephosphonate. 31P NMR (CDCl3), l: 23.7 1H
NMR (CDCl3), l: 1.19 and 1.25 (t, J=7.1 Hz, 3H
each, OCH2CH3); 3.90 (dd, J=3.5/9.2 Hz, 1H, Ha);