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4.3. (1R,2R,3S,4R)-1,2-Dihydroxy-3,4-diacetyloxycyclohex-5-ene (−)-1
Lipozyme (200 mg) and n-BuOH (0.033 ml, 0.36 mmol) were added to a solution of (−)-2 (100 mg,
0.36 mmol, e.e.>95%) in t-BME (10 ml). The reaction was monitored by GC analysis and after 4 h (−)-1
was isolated by column chromatography (hexane:EtOAc=1:1), yield 55%, [α]D −213.2 (c 1.2, CHCl3).
4.4. (1S,2S,3R,4S)-2-Hydroxy-1,3,4-triacetyloxycyclohex-5-ene (+)-2
Lipase from C. cylindracea (140 mg) and vinyl acetate (0.033 ml, 0.36 mmol) were added to a solution
of (+)-1 (70 mg, 0.30 mmol, e.e.>95%) in t-BME (7 ml). After 24 h, conversion was complete (TLC)
and (+)-2 was crystallised from EtOAc:hexane (73 mg, 89% yield); [α]D +275.8 (c 1.2, CHCl3).
4.5. (1R,2S,3R,4S,5R,6R)-1,2-Dihydroxy-3,4-diacetyloxy-5,6-epoxycyclohexane (+)-3
3-Chloroperoxybenzoic acid (650 mg, 3.76 mmol) was added to a solution of (+)-1 (420 mg, 1.82
mmol, e.e.>95%) in CH2Cl2 (20 ml) and the mixture kept at room temperature for 48 h. After evaporation
of the solvent, the residue was subjected to column chromatography (EtOAc:hexane=1:1) to give (+)-3
(385 mg, 86% yield); [α]D +104.6 (c 1.2, CHCl3); 1H NMR (CDCl3) δ 2.06 (3H, s), 2.11 (3H, s), 3.38
(1H, dd, J=3.3 and 2.2), 3.52 (1H, dd, J=3.6 and 3.3), 3.90 (1H, dd, J=9.3 and 5.2), 4.32 (1H, dd, J=5.2
and 3.6), 5.13 (1H, dd, J=9.3 and 3.5), 5.65 (1H, dd, J=3.5 and 2.2); 13C NMR (CDCl3) δ 20.6, 20.7,
54.1, 54.7, 65.4, 66.6, 66.7, 68.3, 169.7, 170.5.
4.6. 1L-1,2-Diacetoxy-4-azido-4-deoxy-chiro-inositol (−)-4
NaN3 (154 mg, 2.36 mmol) and NH4Cl (126 mg, 2.35 mmol) were added to a solution of epoxide (+)-3
(345 mg, 1.40 mmol) in DMF (8 ml). The suspension was stirred for 36 h at 50°C and then filtered. The
filtrate was taken to dryness and the residue purified on Si gel (EtOAc:hexane=3:2) to give azidoinositol
(−)-4 (323 mg, 79% yield); [α]D −37.2 (c 0.5, CHCl3); 1H NMR (CD3OD) δ 2.04 (3H, s), 2.09 (3H, s),
3.64 (3H, m), 3.89 (1H, m), 5.18 (1H, m), 5.31 (1H, m); 13C NMR (CD3OD) δ 20.7, 20.9, 67.9, 70.8,
71.0, 71.2, 71.8, 73.0, 171.3, 172.0. Anal. calcd for C10H15N3O7: C, 41.52; H, 5.23; N, 14.53. Found: C,
41.58; H, 5.29; N, 14.47.
4.7. 1L-1,2-Diacetoxy-4-amino-4-deoxy-chiro-inositol (−)-5
Azido compound (−)-4 (300 mg, 1.02 mmol) in EtOH (8 ml) was hydrogenated in the presence of Pd/C
(20 mg) at barometric pressure and room temperature. After 24 h, the reaction mixture was centrifuged
and filtered and the supernatant taken to dryness to give (−)-5 (263 mg, 98% yield); [α]D −20.8 (c 0.4,
EtOH); 1H NMR (D2O): δ 2.10 (3H, s), 2.15 (3H, s), 3.42 (1H, t, J=10.6), 4.06 (3H, m), 5.11 (1H, dd,
J=10.0 and 3.1), 5.36 (1H, t, J=3.1); 13C NMR (CD3OD) δ 20.6, 20.7, 56.4, 68.5, 68.9, 70.6, 71.7, 73.4,
171.1, 171.9.
4.8. 1L-4-Amino-4-deoxy-chiro-inositole-hexaacetate (+)-6
An aliquot of (−)-5 was subjected to conventional acetylation (Ac2O/py) to give (+)-6; [α]D +13.7 (c
0.3, C6H6); 1H NMR (C6D6) δ 1.46 (3H, s), 1.59 (3H, s), 1.65 (3H, s), 1.72 (3H, s), 1.75 (6H, s), 4.71
(1H, d, J=9.9), 5.06 (1H, ddd, J=11.2, 10.3 and 9.9), 5.32 (1H, dd, J=11.2 and 2.8), 5.50 (1H, t, J=10.3),