CHEM01200604012 Dibakar Goswami - Homi Bhabha National ...

mmol) in one lot. After stirring for 3 h, the reaction mixture was diluted with Et 2 O (30
mL), and the supernatant passed through a pad of silica gel (2″ x 1″). Removal of solvent
in vacuo followed by column chromatography of the residue (silica gel, 0-10%
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EtOAc/hexane) furnished pure 131. Yield: 1.40 g (88%); colourless oil; [α] D +2.62 (c
2.03, CHCl 3 ); IR: 1741 cm -1 ; 1 H NMR: δ 1.05 (s, 9H), 1.14 (d, J = 7.2 Hz, 3H), 1.41-1.63
(m, 10H), 2.50-2.72 (m, 1H), 2.84 (dd, J = 7.2, 11.4 Hz, 2H), 3.62 (t, J = 7.2 Hz, 1H),
3.94-4.16 (m, 2H), 4.18-4.23 (m, 1H), 4.82-5.07 (m, 2H), 5.64-5.84 (m, 1H), 7.24-7.46 (m,
6H), 7.62-7.74 (m, 4H); 13 C NMR: δ 9.0, 19.3, 23.8, 25.1, 27.0, 34.3, 35.8, 45.5, 51.2,
67.6, 74.9, 75.2, 109.6, 117.7, 127.8, 127.9, 130.0, 130.1, 131.2, 133.1, 136.0, 206.8. Anal.
Calcd. for C 31 H 42 O 4 Si: C, 73.47; H, 8.35%. Found: C, 73.25; H, 8.53%.
(4S,5S,6S,7R)-6-(tert)-Butyldiphenylsilyloxy-7,8-cyclohexylidenedioxy-5-methyloct-1-
en-4-ol 132. To a cooled (0 o C) and stirred suspension of NaBH 4 (0.082 g, 2.157 mmol) in
MeOH (10 mL) was added 131 (1.09 g, 2.16 mmol) in MeOH (10 mL). After stirring the
mixture at the same temperature for 3 h (cf. TLC), the mixture was brought to room
temperature, the supernatant decanted and concentrated in vacuo. The residue was taken in
Et 2 O (25 mL), washed with H 2 O (10 mL) and brine (10 mL), and dried. Removal of
solvent in vacuo followed by column chromatography of the residue (silica gel, 0-10%
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EtOAc/hexane) furnished pure 132. Yield: 1.04 g (95%); colourless oil; [α] D +20.1 (c
1.2, CHCl 3 ); IR: 3443 cm -1 ; 1 H NMR: δ 1.06 (overlapping d and s, J = 7.0 Hz, 12H), 1.27-
1.54 (m, 10H), 1.77-1.82 (m, 1H), 1.88-2.04 (m, 2H), 2.75 (broad s, 1H), 3.55-3.63 (m,
2H), 4.02-4.17 (m, 3H), 4.92-4.99 (m, 2H), 5.61-5.75 (m, 1H), 7.34-7.44 (m, 6H), 7.64-
7.70 (m, 4H); 13 C NMR: δ 11.1, 19.4, 23.9, 25.0, 27.1, 35.0, 35.7, 39.6, 43.6, 68.5, 72.8,
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