G. Fantin et al. / Tetrahedron: Asymmetry 11 (2000) 2367±2373
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b-cyclodextrin in OV 1701 from Mega s.n.c.: carrier gas: helium 82 kPa. For the oxidation of 1a:
temperature 90±200ꢀC (1ꢀC/min), retention time (min): (1S,5R)-2a, 6.73; (1R,5S)-2a, 7.22;
(1S,5R,6S)-1a, 12.65; (1R,5S,6R)-1a, 12.83. For the oxidation of 1b: temperature 100±200ꢀC
(1.5ꢀC/min), retention time (min): (1S,5S)-2b, 11.56; (1R,5R)-2b, 11.81; (1S,2S,5S)-1b (as acetyl
derivative), 16.96; (1R,2R,5R)-1b (as acetyl derivative), 16.82. For the oxidation of 1c: temperature
70±200ꢀC (1.5ꢀC/min), retention time (min): (S)-2c, 11.71, (R)-2c, 11.88, (1R,2S)-1c (as acetyl
derivative), 17.43; (1S-2R)-1c (as acetyl derivative), 18.00. For the oxidation of 1d: temperature
80±150ꢀC (0.5ꢀC/min), retention time (min): 2d, 4.41; (S)-1d, 6.95, (R)-1d, 7.08. For the oxidation
of 1e: temperature 80±200ꢀC (1.5ꢀC/min), retention time (min): 2e, 9.45, (S)-1e, 13.27, (R)-1e,
13.85. For the oxidation of 1f: temperature 80±200ꢀC (0.5ꢀC/min), retention time (min): 2f, 6.34;
(R)-1f, 10.51; (S)-1f, 11.15. For the oxidation of 1g: temperature 70±200ꢀC (1.5ꢀC/min), retention
time (min): (S)-2c, 11.27; (R)-2c, 11.47; (1R,2R)-1g (as acetyl derivative), 16.41; (1S-2S)-1g (as
acetyl derivative), 17.45. For reduction with baker's yeast (or YL2): temperature: 85ꢀC, retention
time (min): (S)-2c, 12.31; (R)-2c, 12.49; (1R,2R)-1g (as acetyl derivative) 22.17; (1R,2S)-1c (as
acetyl derivative), 23.58; (1S,2S)-1g (as acetyl derivative) 24.07; (1S-2R)-1c (as acetyl derivative),
24.58.
The absolute con®gurations of the compounds were determined comparing the sign of their
speci®c rotation with those of the literature: for (1R,5S,6R)-1a6 [ꢀ]D=^68 (c 1.1, CHCl3); for
(1S,5R)-2a6 [ꢀ]D=^63 (c 1.2, CHCl3); for (1R,2R,5R)-1b6 [ꢀ]D=151 (c 1.5, CHCl3); for (1S,5S)-
2b6 [ꢀ]D=^502 (c 1.3, CHCl3); for (R)-2c14 [ꢀ]D=14 (c 0.23, MeOH); for (1S,2R)-1c14 [ꢀ]D=18 (c
1.0, MeOH); for (R)-1d7 [ꢀ]D=^12.1 (c 4.6, CHCl3); for (R)-1e7 [ꢀ]D=^14.5 (c 1.3, EtOH); for
(R)-1f7 [ꢀ]D=^25.9 (c 3.5, CHCl3); for (1R,2R)-1g15 [ꢀ]D=^38.2 (c 9.6, EtOH).
3.2. Culture media
Culture medium A (Saboraud): glucose (40 g/L) and peptone (10 g/L). Culture medium B:
yeast extract (4 g/L), malt extract (10 g/L) and glucose (4 g/L).
3.3. Microorganisms
Yarrowia lipolytica strains9 were isolated from various habitat and belong to DPVA (Dipartimento
di Protezione e Valorizzazione Agroalimentare, University of Bologna, Italy). Ten strains9 were
tested in the oxidation of racemic alcohols: YL2 (Y9), YL6 (Y5), YL8 (1A), YL12 (RO13), YL13
(RO18), YL14 (RO21), YL15 (16B), YL17 (PO6), YL18 (PO17), YL19 (PO23).
3.4. Screening of oxidation with Y. lipolytica strains of the alcohols 1a±h on analytical scale.
General procedure
The sterilized (120ꢀC for 20 min) culture medium A (or B) (10 mL) was pre-inoculated with a
spore suspension of the selected Yarrowia lipolytica and grown for 24 h at 28ꢀC. The grown culture
(0.2 mL) was added to 10 mL of culture medium A (or B) and grown for a further 48 h at 28ꢀC.
To the culture was added the selected substrate solution (100 mL, 10 mg) (the solution was prepared
dissolving 0.1 g of the selected substrate in 1 mL of DMF). Aliquots were withdrawing periodically,
extracted with diethyl ether, dried over anhydrous Na2SO4 and monitored by GLC on chiral
column using 2-hexanol as internal standard. The most signi®cant results are summarized in
Table 1.