6
5
5
.65 (dt, J ) 16.8, 10.6 Hz, 1H), 6.01 (t, J ) 11.0 Hz, 1H),
.53 (t, J ) 10.4 Hz, 1H), 5.21 (dd, J ) 16.8, 1.8 Hz, 1H),
.14 (br d, J ) 10.2 Hz, 1H), 4.68 (ddd, J ) 9.5, 5.1, 3.2
atmosphere of argon was treated dropwise over a period of
15 min with n-BuLi (1.6 M in hexanes, 3.12 mL, 5.0 mmol).
After stirring at 0 °C for 15 min, a solution of 29 (1.10 g,
1.75 mmol) in THF (10 mL) was added dropwise. There-
upon, the reaction mixture was stirred at 0 °C for 1 h and
worked up; 1 N NaOH (40 mL) and TBME (40 mL) were
added sequentially, and the layers were separated. The
organic layer was washed with 1 N NaOH (40 mL) and
Hz, 1H), 4.20 (d, J ) 5.1 Hz, 2H), 4.02-3.93 (m, 2H), 3.68
(
(
t, J ) 4.3 Hz, 1H), 3.26 (dd, J ) 13.4, 3.2 Hz, 1H), 2.88
br dqd, J ) 10.4, 6.9, 4.3 Hz, 1H), 2.79 (dd, J ) 13.4, 9.5
Hz, 1H), 2.72 (br s, 1H), 1.78-1.70 (m, 1H), 1.32 (d, J )
6
.5 Hz, 3H), 1.02 (d, J ) 6.9 Hz, 3H), 1.00 (d, J ) 7.0 Hz,
1
3
3
H), 0.98 (t, J ) 7.9 Hz, 9H), 0.64 (q, J ) 7.9 Hz, 6H); C
, 125 MHz, 300 K): δ 177.1, 152.7, 135.2,
35.1, 132.5, 129.4, 129.3, 128.9, 127.4, 117.4, 78.7, 73.2,
6.1, 55.1, 40.8, 39.6, 37.7, 36.5, 18.8, 13.0, 9.4, 7.0, 5.5;
saturated aqueous NaCl (2 × 40 mL), dried over MgSO
4
,
NMR (DMSO-d
1
6
6
and concentrated in vacuo to give the crude thioester 30 (1.28
g) as a gel, which did not require further purification. An
analytical sample was obtained by purification with flash
IR (film): νmax 3540m (br), 2959s, 2877s, 1785s, 1695m,
chromatography (SiO
9:1 heptane/AcOEt); H NMR (CDCl , 500 MHz, 300 K):
2
1
, 95:5 hexane/AcOEt). R
f
) 0.77 (SiO
2
,
1
455m, 1382s, 1352m, 1237m, 1209s, 1110m, 1076m,
3
-
1
+
1011s, 969m, 737s, 702m cm ; MS (ES ) m/z (%) 1053
δ 7.34-7.23 (m, 5H), 6.64 (dt, J ) 16.8, 10.6 Hz, 1H), 6.02
(t, J ) 11.0 Hz, 1H), 5.52 (t, J ) 10.3 Hz, 1H), 5.22 (d, J
) 16.8 Hz, 1H), 5.14 (d, J ) 10.2 Hz, 1H), 4.11 (s, 2H),
4.09 (t, J ) 4.8 Hz, 1H), 3.58 (dd, J ) 5.9, 3.6 Hz, 1H),
2.94-2.86 (m, 1H), 2.80-2.88 (m, 1H), 1.73-1.56 (m, 1H),
1.20 (d, J ) 7.0 Hz, 3H), 1.05 (d, J ) 6.9 Hz, 3H), 1.01 (t,
J ) 8.0 Hz, 9H), 0.96 (d, J ) 6.9 Hz, 3H), 0.94 (s, 9H),
+
2+
(40, [2 M + Na] ), 1050 (15, [4 M + Ca] ), 793 (27, [3 M
2+
2+
+
Ca] ), 785 (13, [3 M + Na + H] ), 538 (100, [M +
+
2+
Na] ), 535 (18, [2 M + Ca] ).
R)-4-Benzyl-3-[(Z)-(2R,3S,4R,5S,6S)-3-(tert-butyldi-
methyl-silanyloxy)-2,4,6-trimethyl-5-triethyl-silanyloxydeca-
,9-dienoyl]-oxazolidin-2-one (29). A solution of 28 (1.74
g, 3.37 mmol) and 2,6-lutidine (1.03 mL, 8.87 mmol) in CH
Cl (16 mL) at -20 °C under an atmosphere of argon was
(
7
0.69 (q, J ) 8.0 Hz, 6H), 0.10 (s, 3H), 0.06 (s, 3H); 13
NMR (DMSO-d , 125 MHz, 300 K): δ 201.2, 137.5, 134.1,
C
2
-
2
6
treated dropwise with TBSOTf (1.83 mL, 8.00 mmol). The
resulting reaction mixture was allowed to warm-up at 0 °C
within 30 min and was stirred for an additional 2.5 h before
being worked up. TBME (50 mL) and 1 N HCl (30 mL)
were added sequentially, and the layers were separated. The
aqueous layer was extracted with TBME (50 mL). The
organic layers were washed with 1 N HCl (30 mL), saturated
129.4, 128.9, 128.5, 127.1, 117.3, 73.7, 52.8, 41.8, 36.5, 33.2,
26.2, 18.7, 18.5, 12.4, 11.6, 7.1, 5.6, -3.7, -3.8; IR (film):
ν
max 2957s, 2877s, 2857s, 1789s, 1472m, 1455s, 1252s,
1121s, 1075s, 1006s, 1020s, 958s, 837s, 775s, 738s, 700 m
-
1
+
+
cm ; MS (ES ) m/z (%) 561 (13, [M - CH
3
] ), 547 (56,
+
]+), 363 (100, [M -
[M - C
2
H
5
+
] ), 519 (32, [M - C
4
H
9
C
11
H
23OSi] ).
aqueous NaHCO
mL) and were combined, dried over MgSO
trated in vacuo. Purification of the residue by flash chro-
matography (200 g of SiO , 95:5 hexane/AcOEt) afforded
the silyl-ether product 29 as a colorless oil (1.91 g, 90%).
3
(30 mL), and saturated aqueous NaCl (30
(Z)-(2S,3R,4R,5S,6S)-3-(tert-Butyldimethyl-silanyloxy)-
2,4,6-trimethyl-5-triethyl-silanyloxydeca-7,9-dien-1-ol (31).
To a solution of crude 30 (1.28 g) in THF (20 mL) at 0 °C
under an atmosphere of argon were sequentially added LiBH
4
4
, and concen-
2
(300 mg 14 mmol) and EtOH (0.80 mL, 14 mmol)). The
resulting mixture was stirred at 23 °C overnight and then
worked up; 1 N NaOH (30 mL) was added. After stirring
for 1 h at 23 °C, TBME (40 mL) was added, and the layers
were separated. The aqueous layer was extracted with TBME
(2 × 40 mL). The organic layers were washed with 1 N
NaOH (30 mL) and saturated aqueous NaCl (2 × 40 mL)
1
R
5
(
2
f
) 0.52 (SiO
00 MHz, 300 K): δ 7.37-7.19 (m, 5H), 6.71 (m, 1H), 5.99
t, J ) 11.1 Hz, 1H), 5.68 (t, J ) 10.2 Hz, 1H), 5.19 (m,
H), 4.58 (ddd, J ) 9.8, 4.7, 3.2 Hz, 1H), 4.13 (d, J ) 4.7
Hz, 2H), 4.08 (dd, J ) 7.4, 1.6 Hz, 1H), 4.04 (dq, J ) 7.4,
2 6
, 3:1 heptane/AcOEt). H NMR (DMSO-d ,
6.7 Hz, 1H), 3.59 (dd, J ) 9.0, 1.3 Hz, 1H), 3.24 (dd, J )
13.3, 3.2 Hz, 1H), 2.95 (br dqd, J ) 10.2, 7.0, 1.3 Hz, 1H),
2.72 (dd, J ) 13.3, 9.8, Hz, 1H), 1.47-1.39 (m, 1H), 1.24
4
and were combined, dried over MgSO , and concentrated in
vacuo. Purification of the residue by flash chromatography
(200 g of SiO , 95:5 hexane/AcOEt) afforded the alcohol
31 as a colorless oil (670 mg, 84% over two steps based on
(d, J ) 6.7 Hz, 3H), 1.06 (d, J ) 7.0 Hz, 3H), 1.00 (t, J )
2
8
.0 Hz, 9H), 0.97 (s, 9H), 0.95 (d, J ) 6.8 Hz, 3H), 0.67 (q,
13
1
J ) 8.0 Hz, 6H), 0.18 (s, 3H), 0.15 (s, 3H); C NMR
DMSO-d , 125 MHz, 300 K): δ 175.8, 152.8, 135.4, 133.7,
33.4, 129.4, 128.8, 127.2, 116.5, 72.9, 65.9, 55.4, 43.8, 42.4,
7.7, 35.5, 26.2, 19.5, 18.5, 15.0, 10.9, 7.1, 5.6, -3.4; IR
29). R
f
2 3
) 0.27 (SiO , 9:1 heptane/AcOEt). H NMR (CDCl ,
(
1
3
6
500 MHz, 300 K): δ 6.60 (dt, J ) 16.8, 10.6 Hz, 1H), 6.04
(t, J ) 11.0 Hz, 1H), 5.60 (t, J ) 10.4 Hz, 1H), 5.22 (dd, J
) 16.8, 1.8 Hz, 1H), 5.14 (d, J ) 10.1 Hz, 1H), 3.71 (t, J )
4.1 Hz, 1H), 3.61 (br dd, J ) 10.6, 7.0 Hz, 1H), 3.56 (dd, J
) 7.0, 3.3 Hz, 1H), 3.44 (br dd, J ) 10.6, 6.4 Hz, 1H),
2.94-2.86 (m, 1H), 1.91-1.82 (m, 1H), 1.72 (br t, 1H),
1.73-1.66 (m, 1H), 1.05 (d, J ) 6.9 Hz, 3H), 1.00 (t, J )
8.0 Hz, 9H), 0.97 (d, J ) 6.9 Hz, 3H), 0.94 (s, 9H), 0.85 (d,
J ) 6.9 Hz, 3H), 0.67 (q, J ) 8.0 Hz, 6H), 0.12 (s, 3H),
(film): νmax 2957s, 2878s, 1785s, 1697s, 1455m, 1382s,
1
210s, 1120s, 1078m, 1048m, 1020s, 969m, 835s, 774m,
-
1
+
739s, 702m cm ; MS (ES ) m/z (%) 964 (25, [3 M +
2+
2+
+
Ca] ), 956 (7, [3 M + Na + H] ), 652 (100, [M + Na] ),
2+
6
49 (38, [2 M + Ca] ).
Z)-(2R,3S,4R,5S,6S)-3-(tert-Butyldimethyl-silanyloxy)-
,4,6-trimethyl-5-triethyl-silanyloxydeca-7,9-dienethioic
(
1
3
2
6
0.10 (s, 3H); C NMR (DMSO-d , 125 MHz, 300 K): δ
Acid S-Benzyl Ester (30). A solution of benzyl mercaptan
0.80 mL, 6.8 mmol) in THF (20 mL) at 0 °C under an
134.5, 132.4, 129.0, 117.4, 77.8, 73.5, 65.9, 40.7, 40.2, 35.9,
26.1, 19.0, 18.4, 12.2, 11.7, 7.1, 5.7, -3.6, -3.9; IR (film):
(
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