CHEM01200604012 Dibakar Goswami - Homi Bhabha National ...

(m, 12H), 1.61-1.72 (m, 2H), 3.36-3.48 (m, 2H), 3.62 (t, J=7.2Hz, 1H), 3.71 (dd, J = 2.2
and 6.4 Hz, 1H), 3.86-3.93 (m, 1H), 4.09-4.16 (m, 1H), 7.25-7.47 (m, 6H), 7.66-7.73 (m,
4H); 13 C NMR: δ 15.2, 19.3, 23.7, 23.8, 25.0, 26.9, 33.8, 34.5, 35.2, 35.9, 60.7, 67.4, 75.6,
77.5, 108.9, 127.3, 127.4, 129.5, 129.6, 133.4, 133.5, 135.8. Anal. Calcd. for C 29 H 42 O 4 Si:
C, 72.15; H, 8.77%. Found: C, 72.34; H, 8.52%.
(2R,3S,4S)-1,2-O-Cyclohexylidene-3-O-(tert)-butyldiphenylsilyl-4-Methyl-6-
benzyloxyhexane 178. Reaction of 177 (2.80 g, 5.81 mmol) with BzCN (0.83 mL, 6.97
mmol) and Et 3 N (1.2 mL, 8.71 mmol) in CH 2 Cl 2 (15 mL), followed by work up, isolation
and purification by column chromatography (silica gel, 0-10% EtOAc/hexane) furnished
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pure 178. Yield: 3.06 g (90%); light yellow oil; [α] D -8.7 (c 1.2, CHCl3 ); IR: 1719, 909
cm -1 ; 1 H NMR: δ 1.04 (d merged with s, 12H), 1.31-1.49 (m, 10H), 1.59-1.65 (m, 1H),
1.85-1.93 (m, 2H), 3.54-3.62 (m, 1H), 3.70 (dd, J = 1.8 and 7.0 Hz, 1H), 3.87-3.95 (m,
1H), 4.09-4.20 (m, 3H), 7.25-7.38 (m, 9H), 7.50-7.66 (m, 4H), 7.90-7.99 (m, 2H); 13 C
NMR: δ 14.7, 19.3, 23.7, 25.0, 26.7, 26.9, 31.3, 34.4, 34.6, 35.9, 63.2, 67.6, 75.4, 77.3,
190.0, 127.4, 128.1, 129.4, 129.6, 130.3, 132.5, 133.3, 133.5, 135.8, 166.2.
(2R,3S,4S)-3-O-(tert)-butyldiphenylsilyl-4-Methyl-6-O-benzoyl-1,2,3,6-tetrahydroxyhexane
179. A mixture of 178 (2.8 g, 4.78 mmol) in CH 2 Cl 2 (25 mL) and aqueous 80%
TFA (10 mL) was stirred for 3 h at 0 °C. The mixture was diluted with water (50 mL) and
extracted with CHCl 3 (50 mL), the organic layer separated and the aqueous layer extracted
with CHCl 3 (20 mL). The organic extract was washed successively with aqueous 2%
NaHCO 3 (10 mL), H 2 O (20 mL) and brine, and dried. Solvent removal in vacuo followed
by column chromatography of the residue (silica gel, 0-5% MeOH/CHCl 3 ) furnished pure
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