336
(silica gel, CH2Cl2/EtOH 95/05) to give pure (–)–ψ-endo-30 18]+, 401 (14.1%) [M + 1]+, 297 (12.0%), 280 (10.8 %); Anal.
(870.0 mg).
Calcd for C19H20FeO6: C, 43.87; H, 3.99. Found: C, 43.97; H,
SM: CH2Cl2/EtOH 95/05 Rf 0.51 (yellow solid, 69%); IR 4.00; [α]D = –48.2 (C = 2.0 g/100 mL, CH2Cl2, 23 °C).
(KBr) 2929 (νCH), 2060, 1990 (νCO complex), 1754, 1714
1
(2S,3S)-2-Benzyloxymethyl-3-buta-1E,3-dienyl-[1,4]dioxane
32
(νCO ester), 1460, 1204, 1114, 612, 561; H NMR (CDCl3,
300 MHz) δ 7.37–7.29 (m, 5H, aromatics), 5.27–5.18 (m, 2H,
CH complex), 4.55 (s, 2H, OCH2Ph), 3.76–3.60 (m, 7H), 3.53
(dd, 1H, J= 9.4 and 6.7 Hz), 3.45 (dd, 1H, J= 9.6 and 4.6 Hz),
2.68 (t, 1H, OH, J = 6.7 Hz), 1.63 (t, 1H, J = 7.0 Hz), 1.19 (q,
1H, CH complex, J = 7.3 Hz), 1.06 (dd, 1H, CH complex,
J= 5.6 and 7.6 Hz); 13C NMR (CDCl3, 75 MHz) δ 210.7 (3 CO
complex), [137.3, 128.3, 127.6, 127.5] (aromatics), 82.6 and
81.4 (s, CH complex), 79.4, 74.6, 73.3, 72.2, 64.3, 62.7, 62.1,
60.5; MS (CI, NH3) m/z 436 (100 %) [M+18]+, 419 (7.4 %)
[M + 1]+, 401 (26%) [M–OH]+, 357 (99.7 %) [M–
OCH2CH2OH]+, 296 (20.7%), 93 (27.8); Anal. Calcd for
C19H22FeO7: C, 54.60; H, 5.30. Found: C, 54.53; H, 5.31;
[α]D = –9.5 (C = 2.0 g/100 mL, CH2Cl2, 26 °C).
The preparation of the optically active benzylated complex
(–)–(2S,3S)-32 (200.0 mg, 0.5 mmol) is carried out in the same
fashion as the preparation of the decomplexed rac-20. Purifi-
cation of crude (–)–32 is best accomplished by flash chroma-
tography (silica gel, hexane/ethyl ether 1/1) to give the pure
optically active (–)–(2S,3S)-32 (120.0 mg).
SM: hexane/ethyl ether 1/1 Rf 0.48 (colorless oil, 92%); IR
(KBr) 2857 (νCH), 1605 (νCH=CH), 1453, 1353, 1274, 1119,
1006, 904, 737, 698; 1H NMR (CDCl3, 300 MHz) δ 7.33–7.26
(m, 5H, aromatics), 6.32–6.23 (m, 2H, H-alkene), 5.54 (dd,
1H, H-alkene, J= 14.2 and 7.2 Hz), 5.22 (d, 1H, H-alkene, J=
14.8 Hz), 5.12 (d, 1H alkene, J= 11.0 Hz), 4.62 and 4.22 (2d,
2H, OCH2Ph, J= 12.2 Hz), 4.02 (t, 1H, J= 8.0 Hz), 3.83–3.72
(m, 4H, OCH2CH2O), 3.50 (t, 2H, J = 4.3 Hz), 3.43–3.39 (m,
1H); 13C NMR (CDCl3, 75 MHz) δ [137.7, 135.9, 134.4,
128.8, 128.1] (aromatics), 118.3, 78.8, 73.4, 69.6, 66.6 and
66.0 (-OCH2CH2O-); MS (CI, NH3) m/z 278 (100%) [M+18]+,
261 (43.7%) [M + 1]+; Anal. Calcd for C16H20FeO3: C, 73.80;
H, 7.70. Found: C, 73.31; H, 7.98; [α]D = –37.5 (C = 2.0 g/100
mL, CH2Cl2, 24 °C).
ψ-exo-Tricarbonyl[(2S,3R)-2-Benzyloxymethyl-3-buta-1E,3-
dienyl-[1,4]dioxane]iron 31
The preparation of the optically active iron-complexed
trans-dioxane (–)–(2S,3R)–31 from the starting diol (–)–ψ-
endo-30 is carried out in the same fashion as described in ref 4.
Starting from (–)–30 (420.0 mg, 1.0 mmol), it allows the
obtention of the optically active (–)–31 (290.0 mg). Its analyti-
cal and spectroscopic data are detailed below.
(2R,3R)-(3-Benzyloxymethyl-[1,4]dioxan-2-yl)-methanol 33
The obtention of (–)–(2R,3R)-33 by the sequence ozoniza-
tion/NaBH4-mediated ozonide reduction is similar to the
preparation of rac-21. Accordingly, the benzylated diene
(–)–32 (260.0 mg, 1.0 mmol) affords the pure optically active
(–)–(2R,3R)–33 (190.0 mg) (flash chromatography on a silica
gel column, hexane/ethyl ether 1/1).
SM: hexane/ethyl ether 1/1 Rf 0.12 (colorless oil, 87%);
chiral analytical HPLC: same conditions as for (–)–(2S,3R)–
31, retention time 10.5 min, optical purity greater than 97.0%;
IR (KBr) 3456 (νOH), 2857 (νCH), 1721, 1454, 1366, 1262,
1116, 923, 847, 739, 699; 1H NMR (CDCl3, 300 MHz) δ 7.37–
7.25 (m, 5H, aromatics), 4.62 and 4.50 (2d, 2H, –OCH2Ph,
J= 12.2 and 18.1 Hz), 3.84–3.47 (m, 10H); 13C NMR (CDCl3,
75 MHz) δ [137.3, 129.5, 128.3, 127.6] (aromatics), 77.6,
75.6, 73.5, 69.7, 66.6 and 66.3 (OCH2CH2O), 62.3; MS (CI,
NH3) m/z 256 (100%) [M+18]+, 239 (14.9 %) [M + 1]+; High
Resolution EI-MS m/z Calcd for C13H16O4, 238.1205. Found:
238.1208 [M]+. Calcd for C12H15O3, 207.1021. Found:
207.1021; Anal. Calcd for C18H18O3: C, 73.80; H, 7.70. Found:
C, 73.31; H, 7.98; [α]D = –12.5 (C = 2.0 g/100 mL, CH2Cl2,
23 °C).
SM: hexane/ethyl ether 1/1 Rf 0.44 (yellow solid, 72%);
chiral analytical HPLC on a Chiracel OD column (column
temperature 20 °C) eluted isocratically by the mixture hexane/
isopropanol 95/05, 0.8 mL/min, λUV 230 nm, retention time
12.5 min, optical purity greater than 96.0%; IR (KBr) 2885
(νCH), 2058 and 1965 (νCO carbonyl and νC=C aromatics), 1055;
1H NMR (C6D6, 300 MHz) δ 7.23–7.03 (m, 5H, aromatics),
5.28 (dd, 1H, internal CH complex, J = 4.9 and 8.6 Hz), 4.60
(ddd, 1H, internal CH complex, J = 4.9, 6.4 and 9.1 Hz), 4.35
(d, 1H, OCH2Ph, J = 12.1 Hz), 4.16 (d, 1H, OCH2Ph, J = 12.1
Hz), 3.70 (dd, 1H, CH complex, J = 2.0 and 8.6 Hz), 3.37 (t,
2H, J = 8.6 Hz), 3.32–3.24 (m, 4H, OCH2CH2O), 3.12–3.07
(m, 1H), 1.28 (dd, 1H, syn CH complex, J = 1.1 and 6.3 Hz),
1.01 (dd, 1H, J = 1.8 and 8.7 Hz), –0.13 (dd, 1H, anti CH
complex, J = 1.6 and 9.1 Hz); 1H NMR (CDCl3, 300 MHz) δ
7.36–7.25 (m, 5H, aromatics), 5.46 (dd, 1H, internal CH com-
plex, J= 4.9 and 8.6 Hz), 5.19 (ddd, 1H, internal CH complex,
J = 4.9, 6.5 and 9.1 Hz), 4.67 and 4.38 (d, 1H, OCH2Ph, J =
12.2 Hz), 3.82–3.79 (m, 1H), 3.76–3.57 (m, 4H), 3.56–3.46
(m, 2H), 3.30–3.25 (m, 1H), 1.60 (dd, syn CH complex, J= 1.7
and 6.8 Hz), 0.79 (dd, 1H, CH complex, J = 2.6 and 8.8 Hz),
–0.4 (dd, 1H, anti CH complex, J= 2.0 and 9.1 Hz); 13C NMR
(C6D6, 75 MHz) δ 210.2 (3 CO complex), [138.6, 128.6, (2S,3R)-3-Benzyloxymethyl-[1,4]dioxane-2-carbaldehyde 34
127.7] (aromatics), 84.3 and 80.7 (CH complex), 81.1 and The ozonization protocol is strictly identical to the one
76.7 (CH-O), 73.5 (OCH2Ph), [70.5, 66.8, 66.6] (CH2–O), developed toward rac-21, except that the ozonide is destroyed
60.7 (CH complex), 38.9 (CH2 complex); 13C NMR (CDCl3, by excess Me2S (0.5 mL) before similar processing. (–)–
75 MHz) δ 210.4 (3 CO complex), [137.5, 128.2, 127.8] (2S,3S)–32 (520.0 mg, 2.0 mmol) affords the pure (2S,3R)–
(aromatics), 83.8 (internal CH complex), 80.6 and 75.6 (CH– dioxane aldehyde 34 (300.0 mg) after flash chromatography
O), 80.5 (internal CH complex), 73.1 (OCH2Ph), [69.3, 66.7 (silica gel column, CH2Cl2/EtOH 95/05).
and 66.2] (CH2–O), 59.3 (CH complex), 38.6 (CH2 complex);
SM: CH2Cl2/EtOH 95/05 Rf 0.38 (colorless paste, 65%);
MS (CI, NH3) m/z 435 (100 %) [M+35]+, 418 (82.3%) [M + 1H NMR (CDCl3, 300 MHz) δ 9.56 (s, 1H, CHO), 7.32–7.26
Israel Journal of Chemistry
41
2001