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4.13. (2S,6S,7S)-7-(Benzyloxy)-2-[1-(tert-butyl)-1,1-
diphenylsilyl]oxy-6-methylnonan-4-one (17)
28.2, 26.9, 24.9, 22.5, 19.0, 17.2, 10.1; MS (ESI): m/z 533
(MþþH); ESI-HRMS, m/z calcd for C34H49O3Si (MþþH):
533.3450, found: 533.3444.
To a stirred solution of dithiane 16 (5.8 g, 9.57 mmol) in
40 mL CH3CNeCH2Cl2eH2O (8:1:1) was added freshly pre-
pared DesseMartin periodinane (7.848 g, 19.14 mmol) in one
portion. The reaction mixture was stirred at room temperature,
exposed to air, for 2 h until complete consumption of starting
material was observed by TLC. The reaction mixture was
diluted with 50% aq NaHCO3, the layers were separated, and
the aqueous layer was extracted with CH2Cl2 (3ꢃ50 mL). The
combined organic layers were washed with brine, dried over
Na2SO4, and concentrated in vacuo. Purification by silica gel
column chromatography using 4% ethyl acetateehexane as
eluent furnished ketone 17 (4.197 g, 85% yield) as a pale yel-
lowish liquid; [a]D25 ꢀ1.2 (c 3.75, CHCl3); IR (Neat): nmax
3068, 2963, 2932, 2858, 1712, 1458, 1427, 1374, 1108, 993,
4.15. (2S,4R,6S,7S)-7-(Benzyloxy)-2-[1-(tert-butyl)-1,1-
diphenylsilyl]oxy-4,6-dimethylnonan-4-ol (18b)
[a]2D5 ꢀ13.54 (c 4.34, CHCl3); IR (Neat): nmax 3446, 2961,
2923, 2853, 1462, 1378, 1108, 702 cmꢀ1
;
1H NMR
(300 MHz, CDCl3): d 7.80e7.69 (m, 4H), 7.46e7.33 (m, 6H),
7.32e7.15 (m, 5H), 4.48 (s, 2H), 4.28e4.13 (m, 1H), 3.87 (br
s, 1H, ꢀOH), 3.15e3.06 (m, 1H), 2.13e1.98 (m, 1H), 1.82
(dd, J¼14.3, 9.0 Hz, 1H), 1.56e1.44 (m, 3H), 1.39 (dd,
J¼14.3, 3.7 Hz, 1H), 1.28e1.09 (m, 4H), 1.02 (s, 9H), 0.96
(d, J¼6.8 Hz, 3H), 0.96 (d, J¼6.8 Hz, 3H), 0.93 (t, J¼7.5 Hz,
3H); 13C NMR (75 MHz, CDCl3): d 138.9, 135.8, 135.7,
134.3, 133.1, 129.8, 129.5, 128.1, 127.7, 127.3, 85.5, 72.3,
71.3, 69.1, 49.7, 46.6, 30.2, 27.0, 26.8, 25.0, 22.2, 19.0, 17.4,
9.9; MS (ESI): m/z 533 (MþþH); ESI-HRMS, m/z calcd for
C34H49O3Si (MþþH): 533.3450, found: 533.3452.
738 cmꢀ1 1H NMR (400 MHz, CDCl3): d 7.70e7.61 (m,
;
4H), 7.42e7.30 (m, 6H), 7.30e7.16 (m, 5H), 4.47 (d,
J¼11.0 Hz, 1H), 4.41 (d, J¼11.0 Hz, 1H), 4.31e4.23 (m, 1H),
3.09e3.01 (m, 1H), 2.56 (dd, J¼15.4, 5.9 Hz, 1H), 2.40 (dd,
J¼16.2, 4.4 Hz, 1H), 2.35 (dd, J¼16.2, 5.9 Hz, 1H), 2.29e
2.20 (m, 1H), 2.14 (dd, J¼16.2, 8.1 Hz, 1H), 1.54e1.40 (m,
2H), 1.05 (d, J¼6.6 Hz, 3H), 1.01 (s, 9H), 0.90 (t, J¼7.3 Hz,
3H), 0.84 (d, J¼6.6 Hz, 3H); 13C NMR (75 MHz, CDCl3):
d 138.8, 135.7, 134.7, 134.3, 129.6, 129.5, 128.1, 127.6,
127.5, 127.4, 127.3, 83.8, 71.4, 66.3, 52.7, 47.1, 31.1, 26.9,
26.5, 23.6, 22.8, 19.1, 16.0, 9.5; MS (ESI): m/z 517 (MþþH);
ESI-HRMS, m/z calcd for C33H45O3Si (MþþH): 517.3137,
found: 517.3148.
4.16. (2R,4R,6S,7R)-7-(Benzyloxy)-4,6-dimethylnonane-2,4-
diol (19a)
To an ice-cooled solution of 18a (1.6 g, 3.0 mmol) in dry
THF (15 mL) was added a 1 M solution of TBAF in THF
(6 mL, 6 mmol) and stirred for 4 h at room temperature. After
completion of the reaction, water was added to the reaction mix-
ture and extracted with ethyl acetate. The combined organic ex-
tracts were washed with water (1ꢃ5 mL) and brine (1ꢃ5 mL),
dried over anhydrous Na2SO4, and concentrated in vacuo. The
residue was purified by silica gel column chromatography using
20% ethyl acetateehexane as eluent to afford the alcohol 19a
(0.78 g, 89% yield) as a colorless oil; [a]2D5 ꢀ15.3 (c 2.60,
CHCl3); IR (Neat): nmax 3365, 2968, 2931, 2875, 1457, 1376,
4.14. (2S,4S,6S,7S)-7-(Benzyloxy)-2-[1-(tert-butyl)-1,1-
diphenylsilyl]oxy-4,6-dimethylnonan-4-ol (18a)
To a freshly prepared methyllithium solution [prepared from
methyl iodide (0.725 mL, 11.62 mmol) and lithium (0.054 g,
7.75 mmol)] in dry ether (25 mL) under nitrogen atmosphere
at 0 ꢁC, ketone 17 (4 g, 7.75 mmol) was added slowly. After
the addition was complete, the mixture was allowed to stir at
room temperature for 2 h. The reaction mixture was quenched
with saturated NH4Cl solution (15 mL) and extracted with
diethyl ether (2ꢃ40 mL). The organic extracts were washed
with water (2ꢃ10 mL) and brine (1ꢃ10 mL), dried over anhy-
drous Na2SO4, and concentrated in vacuo. Purification of the
residue by silica gel column chromatography using 5% ethyl
acetateehexane as eluent resulted in the alcohols 18a and 18b
(3.546 g, 87% yield) in 65:35 ratio as colorless liquids; 18a:
[a]2D5 þ2.89 (c 1.73, CHCl3); IR (Neat): nmax 3509, 3070,
1
1275, 1105, 1068, 922, 739, 700 cmꢀ1; H NMR (300 MHz,
CDCl3): d 7.38e7.21 (m, 5H), 4.56 (d, J¼11.3 Hz, 1H), 4.44
(d, J¼11.3 Hz, 1H), 4.16e4.03 (m, 1H), 3.41 (br s, 1H,
ꢀOH), 3.05 (dd, J¼10.5, 6.0 Hz, 1H), 2.01e1.89 (m, 1H),
1.74e1.37 (m, 5H), 1.37e1.19 (m, 1H), 1.15 (s, 3H), 1.10 (d,
J¼6.0 Hz, 3H), 0.99 (d, J¼7.5 Hz, 3H), 0.94 (t, J¼7.5 Hz,
3H); 13C NMR (75 MHz, CDCl3): d 138.5, 128.3, 127.9,
127.5, 85.6, 73.4, 71.6, 65.3, 49.5, 44.1, 31.2, 30.2, 24.3, 22.4,
17.9, 9.3; MS (ESI): m/z 295 (MþþH); ESI-HRMS, m/z calcd
for C18H30O3Na (MþþNa): 317.2092, found: 317.2102.
4.17. (2R,4S,6S,7R)-7-(Benzyloxy)-4,6-dimethylnonane-2,4-
diol (19b)
2964, 2932, 2858, 1454, 1428, 1377, 1111, 1069, 740 cmꢀ1
;
1H NMR (300 MHz, CDCl3): d 7.80e7.65 (m, 4H), 7.44e
7.32 (m, 6H), 7.31e7.19 (m, 5H), 4.45 (s, 2H), 4.28e4.10 (m,
1H), 3.83 (br s, 1H, ꢀOH), 3.07e2.95 (m, 1H), 2.04e1.88 (m,
1H), 1.77 (dd, J¼14.8, 9.0 Hz, 1H), 1.60e1.37 (m, 5H), 1.10
(s, 3H), 1.01 (s, 9H), 0.96 (d, J¼6.6 Hz, 3H), 0.95 (d,
J¼6.6 Hz, 3H), 0.90 (t, J¼6.6 Hz, 3H); 13C NMR (75 MHz,
CDCl3): d 139.0, 135.8, 135.7, 134.4, 133.3, 129.8, 129.5,
128.2, 127.7, 127.3, 85.8, 72.4, 71.5, 68.9, 50.5, 44.4, 31.0,
In the same manner as described above for compound 19a,
TBDPS ether 18b (1.1 g, 2.06 mmol) was converted into diol
19b (0.547 g, 90% yield) as a colorless liquid; [a]2D5 ꢀ42.86 (c
3.34, CHCl3); IR (Neat): nmax 3377, 2967, 2931, 2875, 1458,
1
1375, 1065, 739 cmꢀ1; H NMR (300 MHz, CDCl3): d 7.39e
7.23 (m, 5H), 4.62 (d, J¼11.3 Hz, 1H), 4.38 (d, J¼11.3 Hz,
1H), 4.20e4.06 (m, 1H), 3.11e3.02 (m, 1H), 2.05e1.88 (m,
1H), 1.87e1.72 (m, 1H), 1.68e1.41 (m, 3H), 1.31e1.19 (m,