CHEM01200604012 Dibakar Goswami - Homi Bhabha National ...

36.7, 41.9, 64.4, 72.2, 73.6, 77.8, 118.0, 127.5, 127.6, 128.3, 129.7, 133.1, 135.8, 136.0,
167.0. Anal. Calcd. for C 32 H 40 O 5 Si : C, 72.14; H, 7.57%. Found: C, 72.05; H, 7.36%.
(1R,2R,3S,4S)-1-Phenyl-2-(tert)-butyldiphenylsilyloxy-3-methyl-4-benzyloxyheptan-1-
ol 142. To a stirred solution of 140 (0.100 g, 0.188 mmol) in 60% aqueous CH 3 CN (20
mL) was added NaIO 4 (0.080 g, 0.376 mmol) in portions. After stirring for 2 h, the mixture
was filtered, the filtrate extracted with CHCl 3 . The organic layer was washed with water
and brine, and concentrated in vacuo to get the aldehyde 141. Yield: 0.088 g (93%);
colourless oil; [α] 23 D + 9.2 (c 1.22, CHCl 3 ); IR: 2710, 1730, 1712 cm -1 ; 1 H NMR: δ 1.10
(overlapping s and d, J = 6.8 Hz, 12H), 1.95-2.03 (m, 1H), 2.21-2.29 (m, 2H), 4.21 (dd, J
= 1.8, 2.4 Hz, 1H), 4.87-5.02 (m, 2H), 5.23-5.29 (m, 1H), 5.62-5.83 (m, 1H), 7.15-7.47 (m,
9H), 7.49-7.60 (m, 4H), 7.78-7.82 (m, 2H), 9.35 (d, J = 1.8 Hz, 1H); 13 C NMR: δ 11.6,
19.5, 27.4, 36.7, 42.1, 74.5, 81.1, 116.9, 127.2, 127.5, 128.1, 129.2, 132.9, 136.0, 136.2,
140.8, 169.2, 203.4. Anal. Calcd. for C 31 H 36 O 4 Si: C, 74.36; H, 7.25%. Found: C, 74.24; H,
7.15%.
To a cooled (-30 °C) and stirred solution of PhMgBr [prepared from 1-
bromobenzene (0.056 g, 0.353 mmol) and Mg-turnings (0.011 g, 0.441 mmol)] in THF (10
mL) was injected 141 (0.075 g, 0.150 mmol) in THF (10 mL). After stirring for 3 h, the
reaction was quenched with aqueous saturated NH 4 Cl (2 mL), the organic layer was
separated and the aqueous portion extracted with Et 2 O (30 mL). The organic extract was
washed with water, brine, and dried. Solvent removal in vacuo and column
chromatography of the residue (silica gel, 0-15% EtOAc/hexane) afforded pure alcohol
22
142. Yield: 0.091 g (84%); white solid; [α] D -5.2 (c 1.21, CHCl3 ); IR: 3478, 1721 cm -1 ;
1 H NMR: δ 1.05 (s, 9H), 1.12 (d, J = 7.4 Hz, 3H), 1.86-2.12 (m, 3H), 2.20-2.49 (m, 1H),
197