2 OH), 3.95 (brs, 1H, OH); 13C NMR (CDCl3): ¤ 11.9 (SiCH),
16.7 (CH3), 18.0 (SiCHCH3), 31.7 (CH2), 33.7 (CH), 39.8
(CH), 63.5 (CH2OH), 65.0 (CH2), 68.9 (CH), 75.7 (CH); MS
(CI-NH3): m/z 335 (M + H+), 176, 162, 149, 144, 126, 108,
96, 75; Anal. Found: C, 60.67; H, 11.82%. Calc. for
C17H38O4Si: C, 61.03; H, 11.45%.
127.9, 128.0, 128.5, 129.8, 133.1, 137.9, 144.7. 42d: [α]D
¹12.2 (c 1.0, CH2Cl2); TLC (hexane:EtOAc = 3:1) Rf = 0.75;
IR (KBr, cm¹1): 2866, 1599, 1455, 1367, 1177, 1097, 957, 814,
1
665, 554; H NMR (CDCl3): ¤ 0.81 (d, J = 6.5 Hz, 3H), 0.89
(d, J = 6.6 Hz, 3H), 0.90-1.32 (m, 25), 1.42-1.71 (m, 2H),
2.23-2.34 (m, 2H), 2.47 (s, 3H), 2.50 (s, 3H), 3.40-3.61 (m,
4H), 3.98 (dd, J = 10.1, 4.0 Hz, 1H), 4.12 (dd, J = 10.1,
3.8 Hz, 1H), 4.41 (d, J = 12 Hz, 2H), 4.78 (m, 1H), 7.23-7.41
(m, 9H), 7.77-7.84 (m, 4H); 13C NMR (CDCl3): ¤ 12.0 (SiCH),
17.3 (CH3), 18.0 (SiCHCH3), 19.8 (CH3), 21.6 (CH3), 27.2
(CH), 33.2 (CH), 33.5 (CH2), 37.3 (CH), 41.5 (CH2), 68.3
(CH2), 68.6 (CH2), 68.9 (CH2), 73.2 (CH2), 81.2 (CH), 127.6,
127.7, 127.8, 127.9, 128.3, 129.6, 129.8, 134.0, 137.4, 144.5,
144.8.
(2S,4R,6R,7R)-8-Benzyloxy-7-hydroxy-6-hydroxymethyl-
2,4-dimethyl-1-triisopropylsilyloxy-octane 42a and
(2R,3R,5R,7S)-8-Triisopropylsilyloxy-3-benzyloxymethyl-
5,7-dimethyl-octan-1,2-diol 42b: Sulfone ent-12a (620 mg,
1.5 mmol) was reacted with epoxide 35b (194.2 mg, 1 mmol)
in the preceding conditions [ent-12a/35b/BuLi molar ratio
1.5:1:2.5] to give, after separation of ent-12a (212 mg, 80%) by
column chromatography (hexane/EtOAc), a mixture of sul-
fones 41a and 41b (601 mg, 99%) which was treated with
Na¢Hg in MeOH as above. Usual processing was followed by
column chromatography (hexane/EtOAc) to obtain successive-
ly diol 42a (331.5 mg, 72%) and the isomeric diol 42b (50.0
mg, 11%), both as viscous colourless oil. 42a: [α]D ¹30.8 (c
1.0, CH2Cl2); TLC (hexane:EtOAc = 2:1) Rf = 0.36; IR (KBr,
cm¹1): 3417, 2943, 1729, 1463, 1383, 1248, 1206, 1099, 882,
789, 735, 682; 1H NMR (CDCl3): ¤ 0.85-1.12 [m, 8H, in which
d at 0.87 (J = 6.5 Hz, 3H) and 0.89 (J = 6.6 Hz, 3H)], 1.26-
1.43 (m, 3H), 1.53-1.75 (m, 3H), 2.89 (brs, 1H, OH), 3.05 (brs,
1H, OH), 3.40-3.53 (m, 3H), 3.58-3.64 (m, 2H), 3.75-3.85 (m,
2H), 4.57 (s, 2H), 7.27-7.39 (m, 5H); 13C NMR (CDCl3): ¤
12.0 (SiCH), 17.4 (CH3), 18.3 (SiCHCH3) 20.2 (CH3), 27.6
(CH), 33.3 (CH), 35.3 (CH2), 39.8 (CH), 41.9 (CH2), 63.9
(CH2), 68.5 (CH2), 73.0 (CH2), 73.4 (CH2), 74.9 (CH), 127.7,
127.8, 128.4, 137.7; MS (CI-NH3): m/z 467 (M + H+), 423,
341, 297, 183, 167, 149, 123, 9. 42b: [α]D ¹32.7 (c 1.0,
CH2Cl2); TLC (hexane:EtOAc = 2:1) Rf = 0.20; IR (KBr,
cm¹1): 2866, 1599, 1455, 1367, 1177, 1097, 957, 814, 665,
(2S,4R,6S,7R)-8-Benzyloxy-2,4,6-trimethyloctane-1,7-diol
19b: The tosylate 42c (281 mg, 0.45 mmol) was reacted with
excess LAH in ether to give, after column chromatography
(hexane/EtOAc), alcohol 19a (187.6 mg) as a colourless oil.
19a: [α]D ¹26.3 (c 1.0, CH2Cl2); TLC (hexane:EtOAc = 3:1)
Rf = 0.65; IR (KBr, cm¹1): 3445, 2943, 2866, 1463, 1381,
1248, 1102, 995, 882, 789, 734, 681; 1H NMR (CDCl3): ¤ 0.85
(d, J = 6.5 Hz, 3H), 0.90 (d, J = 6.6 Hz, 6H), 0.87-1.41 (m,
25H), 1.52-1.78 (m, 3H), 2.29 (brs, 1H, OH), 3.39-3.57 (m,
4H), 3.61-3.70 (m, 1H), 4.55 (s, 2H), 7.27-7.41 (m, 5H);
13C NMR (CDCl3): ¤ 12.0 (CH), 14.3 (CH3), 17.4 (CH3), 18.0
(CH3), 19.8 (CH3), 27.3 (CH), 33.1 (CH), 33.3 (CH), 40.0
(CH2), 42.1 (CH2), 68.6 (CH2), 72.9 (CH2), 73.3 (CH2), 74.5
(CH), 127.6, 127.7, 128.4, 138.0. 19a was then treated by
TBAF¢3H2O (284 mg, 0.9 mmol) in THF (2 mL). After 16 h
stirring at rt, the reaction mixture was diluted with EtOAc
(6 mL) and water (3 mL) and the aqueous phase was thoroughly
extracted with EtOAc (5 © 1 mL). The pooled organic phases
were dried (MgSO4) and the solvents were eliminated in a
vacuum to give, after a purification by column chromatography
(hexane/EtOAc), diol 19b (106 mg; overall 92%, from 42c) as
a colourless oil; [α]D ¹32.9 (c 1.0, CH2Cl2); TLC (hexane:
EtOAc = 1:1) Rf = 0.50; IR (KBr, cm¹1): 3418, 2920, 1455,
1380, 1101, 737, 698; 1H NMR (CDCl3): ¤ 0.84 (d, J = 6.6 Hz,
3H), 0.88 (d, J = 6.7 Hz, 3H), 0.89 (d, J = 6.8 Hz, 3H), 0.90-
1.33 (m, 4H), 1.50-1.77 (m, 3H), 2.45 (brs, 2H, 2 OH), 3.30-
3.55 (m, 3H), 3.53 (dd, J = 9.4, 3.1 Hz, 3H), 3.59-3.67 (m,
1H), 4.53 (s, 2H), 7.24-7.38 (m, 5H); 13C NMR (CDCl3): ¤
14.5 (CH3), 17.2 (CH3), 20.1 (CH3), 27.2 (CH), 32.8 (CH),
32.9 (CH), 39.9 (CH2), 41.6 (CH2), 68.0 (CH2), 72.8 (CH2),
73.3 (CH2), 74.4 (CH), 127.7, 127.8, 128.4, 138.0; Anal.
Found: C, 73.26; H, 10.12%. Calc. for C18H30O3: C, 73.43; H,
10.27%.
1
554; H NMR (CDCl3): ¤ 0.87 (d, J = 6.6 Hz, 3H), 0.89 (d,
J = 6.6 Hz, 3H), 0.90-1.16 (m, 22H), 1.25-1.45 (m, 2H), 1.49-
1.60 (m, 1H), 1.66-1.76 (m, 1H), 1.85-1.94 (m, 1H), 2.54 (brs,
1H, OH), 3.38-3.68 (m, 8H, in which 1 OH), 4.50 (s, 2H),
7.27-7.39 (m, 5H); 13C NMR (CDCl3): ¤ 11.9 (SiCH), 17.5
(CH3), 18.0 (SiCHCH3) 20.2 (CH3), 27.7 (CH), 33.3 (CH),
35.7 (CH2), 38.3 (CH), 41.8 (CH2), 65.0 (CH2), 68.5 (CH2),
71.2 (CH2), 73.6 (CH2), 75.4 (CH), 127.7, 127.9, 128.5, 137.4.
(2S,4R,6R,7R)-8-Benzyloxy-7-hydroxy-6-tosyloxymethyl-
2,4-dimethyl-1-triisopropylsilyloxy-octane 42c:
The diol
42a (270.3 mg, 0.580 mmol) was reacted with TsCl as usual to
give, after separation by column chromatography (hexane/
EtOAc), tosylate 42c (315 mg, 88%), and the bis-tosylate 42d
(48 mg, 4.5%); [α]D ¹17.0 (c 1.0, CH2Cl2); TLC (hexane:
EtOAc = 3:1) Rf = 0.59; IR (KBr, cm¹1): 3445, 2866, 1599,
(2S,4R,6S,7R)-8-Benzyloxy-7-hydroxy-2,4,6-trimethyl-
octyl 4-Methylbenzenesulfonate 19d: Diol 19b (100 mg,
0.34 mmol) was tosylated as usual to give, after purification by
column chromatography (hexane/EtOAc), the tosylate 19d
(113 mg, 74%) as a viscous colourless oil; [α]D ¹13.9 (c 1.0,
CH2Cl2); TLC (hexane:EtOAc = 1:1) Rf = 0.72; IR (KBr,
cm¹1): 3460, 3064, 2924, 1598, 1496, 1455, 1360, 1177,
1
1463, 1361, 1177, 1098, 957, 883, 814, 666, 555; H NMR
(CDCl3): ¤ 0.82 (d, J = 6.5 Hz, 3H), 0.86 (d, J = 6.6 Hz, 3H),
0.87-0.89 (m, 2H), 0.99-1.09 (m, 21H), 1.26-1.32 (m, 1H),
1.36-1.72 (m, 3H), 1.82-1.91 (m, 1H), 2.37 (brs, 1H, OH),
2.43 (s, 3H), 3.38-3.55 (m, 4H), 3.70-3.76 (m, 1H), 4.11 (dd,
J = 9.7, 4.3 Hz, 1H), 4.18 (dd, J = 9.7, 3.5 Hz, 1H), 4.51 (AB
quartet, ¦¯AB = 10.0 Hz, JAB = 11.9 Hz, 2H), 7.27-7.39 (m,
7H), 7.77 (d, J = 8.3 Hz, 2H); 13C NMR (CDCl3): ¤ 12.1
(SiCH), 17.4 (CH3), 18.1 (CH3), 20.3 (CH3), 21.7 (CH3), 27.3
(CH), 33.4 (CH), 34.2 (CH2), 38.5 (CH), 41.8 (CH2), 68.8
(CH2), 69.2 (CH2), 70.5 (CH), 72.4 (CH2), 73.4 (CH2), 127.8,
1
1098, 963, 815, 736, 666, 556; H NMR (CDCl3): ¤ 0.79 (d,
J = 6.5 Hz, 3H), 0.84 (d, J = 6.6 Hz, 3H), 0.87 (d, J = 6.7 Hz,
3H), 0.90-1.21 (m, 4H), 1.41-1.54 (m, 1H), 1.58-1.69 (m, 1H),
1.82-1.93 (m, 1H), 2.43 (s, 3H), 3.37-3.43 (m, 1H), 3.53 (dd,
J = 9.3, 3.0 Hz, 1H), 3.57-3.64 (m, 1H), 3.77 (dd, J = 9.3,
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