CHEM01200604012 Dibakar Goswami - Homi Bhabha National ...

IV.6 EXPERIMENTAL SECTION
(2R,3S,4R)-1,2-Cyclohexylidenedioxy-3-tosyloxy-4-vinyl-decane 105 : To a cooled (0
o C) and stirred solution of compound 79c (3.0 g, 10.13 mmol) in pyridine (10 mL) was
dropwise added a solution of p-TsCl (2.32 g, 12.16 mmol) in pyridine (15 mL) and the
solution was stirred for 3 h (cf. TLC). Water and EtOAc was added to the mixture, the
organic layer separated and the aqueous layer extracted with EtOAc (100 mL). The
combined organic extracts were washed with aqueous HCl, water and brine, and dried.
Solvent removal in vacuo and chromatographic purification (silica gel, 0-15%
EtOAc/Hexane) of the crude residue afforded pure 105. Yield: 3.65 g (80%); colourless
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oil; [α] D +11.32 (c 1.2, CHCl3 ); IR: 1365, 1177, 1096, 930 cm -1 ; 1 H NMR: δ 0.85 (t, J =
6.6 Hz, 3H), 1.16-1.40 (m, 21H), 2.42 (s, 3H), 3.74-3.91 (m, 2H), 4.01-4.11 (m, 1H), 4.66
(dd, J = 7.4 and 2.2 Hz, 1H), 4.99-5.09 (m, 2H), 5.45-5.63 (m, 1H), 7.30 (d, J = 8.2 Hz,
2H), 7.76 (d, J = 8.0 Hz, 2H); 13 C NMR: δ 13.8, 21.3, 22.4, 23.6, 23.7, 24.9, 26.8, 28.8,
30.5, 31.4, 34.6, 35.9, 45.7, 66.2, 74.0, 84.9, 109.5, 118.0, 127.4, 129.5, 134.4, 136.3,
144.4. Anal. Calcd. for C 25 H 38 O 5 S: C, 66.63 H, 8.50 S, 7.12%. Found, C, 66.42; H, 8.61;
S, 6.98%.
(2R,3S,4R)-3-Tosyloxy-4-vinyl-decan-1,2-diol 106 : To a cooled (0 o C) and stirred
solution of 105 (3.1 g, 6.89 mmol) in CH 2 Cl 2 (30 mL) was added aqueous TFA (10 mL) in
portions. When the reaction was complete (~2.5 h, cf. TLC), the mixture was treated with
NaHCO 3 , and water, and the mixture thoroughly extracted with CHCl 3 (50 mL). The
combined organic extracts were washed with water and brine, and dried. Removal of
solvent in vacuo followed by column chromatography (silica gel, 0-5% MeOH/CHCl 3 ) of
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the residue afforded 106. Yield: 1.92 g (78%); colourless oil; [α] D +7.24 (c 1.6, CHCl 3);
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