CHEM01200604012 Dibakar Goswami - Homi Bhabha National ...

1 H NMR: δ 1.03 (s, 9H),1.40-1.62 (m, 10H), 2.66 (m, 1H), 3.63-3.77 (m, 2H), 3.80-4.12
(m, 3H), 5.00-5.22 (m, 2H), 5.82-6.01 (m, 1H), 7.21-7.52 (m, 10H).
(2R,4R)-1,2-Cyclohexylidenedioxy-4-C-(tert)-butyldiphenylsilyloxy-3-one-5-hexene
84d. Colourless oil; Yield: 0.702g (70.0%); [α] 25 D -4.68 (c 1.80, CHCl 3 ); IR: 1717 cm -1 ;
1 H NMR: δ 1.05 (s, 9H),1.38-1.61 (m, 10H), 2.65 (m, 1H), 3.64-3.80 (m, 2H), 3.82-4.13
(m, 3H), 5.04-5.24 (m, 2H), 5.83-6.03 (m, 1H), 7.22-7.55 (m, 10H).
(2R,3R,4R/4S)-1,2-Cyclohexylidenedioxy-4-C-(tert)-butyldiphenylsilyloxy-5-hexene-3-
ol 83a or 83b. To a cooled (-78 o C) and stirred solution of the ketone 84c or 84d (0.5 g,
1.04 mmol) in THF (50 mL) was injected K-selectride (1.0 mL, 1M in THF). The mixture
was stirred at -78 o C for an additional 2 h, gradually brought to room temperature, and
water and EtOAc were added. The organic layer was separated and the aqueous layer
extracted with EtOAc. The combined organic extracts were washed with water and brine,
and dried. Removal of solvent in vacuo followed by column chromatography of the residue
(silica gel, 0-15% EtOAc/hexane) afforded of 83a or 83b.
(2R,3R,4R)-1,2-Cyclohexylidenedioxy-4-C-(tert)-butyldiphenylsilyloxy-5-hexene-3-ol
83a. Colourless oil; Yield: 0.465 (93%); [α] 25 D -2.0 (c 0.9, CHCl3); IR: 3400, 920 cm -1 ;
1 H NMR: δ 1.04 (s, 9H), 1.41 (m, 2H), 1.55-1.62 (m, 8H), 2.25-2.50 (m, 1H), 2.88 (broad
s, 1H), 3.60-3.71 (m, 1H), 3.75-4.02 (m, 4H), 4.11-4.23 (m, 1H), 5.00-5.22 (m, 2H), 5.70-
6.00 (m, 1H), 7.40 (m, 6H), 7.65 (m, 4H); Anal. Calcd. for C 29 H 40 O 4 Si: C, 72.47 H, 8.38%.
Found, C, 72.42; H, 8.44%.
(2R,3R,4S)-1,2-Cyclohexylidenedioxy-4-C-(tert)-butyldiphenylsilyloxy-5-hexene-3-ol
83b. Colourless oil; Yield: 0.456 g (91.5%); [α] 25 D -7.2 (c 1.0, CHCl3); IR: 3400, 922 cm -
1 ; 1 H NMR: δ 1.03 (s, 9H), 1.42 (m, 2H), 1.56-1.62 (m, 8H), 1.90 (broad s, 1H), 2.23-2.44
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