CHEM01200604012 Dibakar Goswami - Homi Bhabha National ...

23
(2R,3S,4R)-1,2-Cyclohexylidenedioxy-4-vinyldecan-3-ol 79b : Colourless oil; [α] D
12.04 (c 4.6, CHCl 3 ); IR: 3476, 2931, 2857, 1639, 1103 cm -1 ; 1 H NMR: δ 0.82 (broad t,
3H), 1.24 (m, 10H), 1.38 (m, 2H), 1.5-1.7 (m, 8H), 1.95 (broad s, 1H), 2.32 (m, 1H), 3.72
(dd, J = 8.8, 3.4 Hz, 1H), 3.80-3.95 (m, 2H), 4.07-4.16 (m, 1H), 5.0-5.2 (m, 2H), 5.5-5.7
(m, 1H). 13 C NMR: δ 13.95, 22.53, 23.67, 23.84, 24.89, 26.66, 29,20, 30.33, 31.71, 34.82,
36.02, 47.52, 63.37, 72.50, 76.47, 109.01, 116.67, 138.50. Anal. calcd. for C 18 H 32 O 3 : C,
72.93; H, 10.88%. Found, C, 72.95; H, 10.67%.
23
(2R,3R,4S)-1,2-Cyclohexylidenedioxy-4-vinyldecan-3-ol 79c : Colourless oil; [α] D
+17.71 (c 2.6, CHCl 3 ); IR: 3465, 2931, 2856, 1101, 913 cm -1 ; 1 H NMR: δ 0.84 (broad t,
3H), 1.25 (m, 10H), 1.38 (m, 2H), 1.56-1.66 (m, 8H), 2.19-2.38 (m, 1H), 3.68 (t, J = 4.5
Hz, 1H), 3.8-4.0 (m, 3H), 4.71 (broad s, 1H), 5.0-5.2 (m, 2H), 5.6-5.8 (m, 1H); 13 C NMR:
δ 14.0, 22.6, 23.8, 24.0, 25.1, 27.1, 29,2, 31.0, 31.7, 34.8, 36.3, 46.40, 65.4, 73.9, 76.4,
109.0, 117.5, 137.9. Anal. calcd. for C 18 H 32 O 3 : C, 72.93; H, 10.88%. Found, C, 73.05; H,
10.80%.
4-(tert)-Butyldiphenylsilyloxy-2Z-buten-1-ol 81. To a cooled (0 o C) and stirred solution
of 80 (5.0 g, 56.81 mmol) and imidazole (4.25 g, 62.5 mmol) in CH 2 Cl 2 (75 mL) was
added TBDPSCl (17.12 g, 62.5 mmol) in CH 2 Cl 2 (25 mL). After stirring for 2.5 h (cf.
TLC), the mixture was poured into water, the organic layer separated and the aqueous layer
extracted with CHCl 3 . The combined organic extracts were washed with water and brine,
and dried. Solvent removal in vacuo and column chromatography (silica gel, 2-10%
EtOAc/hexane) of the residue afforded pure 81. Yield 14.22 g (77%); colourless oil; IR:
3450, 3397, 3063, 3028 cm -1 ; 1 H NMR: δ 1.1 (s, 9H), 1.93 (broad s, D 2 O exchangeable,
129