3.2 Experimental Procedures
53
1.95 (td, J = 13.5, 5.6 Hz, 1 H, H
15a ), 1.87–1.72 (m, 3 H, H
1a,9,11a ), 1.67–
1.62 (m, 2 H, H
22ab ), 1.56–1.49 (m, 3 H, H
5,6a,7a ), 1.46–1.42 (m, 4 H, H
6b,27 ),
1.40–1.32 (m, 3 H, H
1b,21ab ), 1.31–1.20 (m, 6 H, H
7b,15b,16b,26 ), 1.19 (s, 3 H,
H
24 ), 1.00 (s, 3 H, H
29 ), 0.94 (s, 3 H, H
25 ), 0.90 (s, 3 H, H
30 ).
13 C-NMR
(150 MHz, CDCl 3 , major): δ 178.9 (C
28 ), 171.1 (C
33 ), 170.4 (C
31 ), 169.7
(C
3 ), 91.6 (C
13 ), 68.4 (C
23 ), 56.3 (C
12 ), 52.5 (C
18 ), 48.3 (C
5 ), 45.6 (C
9 ), 44.9
(C
17 ), 44.1 (C
4 ), 43.6 (C
14 ), 42.3 (C
8 ), 40.1 (C
19 ), 37.3 (C
1 ), 36.2 (C
10 ), 34.0
(C
21 ), 33.8 (C
7 ), 33.4 (C
29 ), 32.0 (C
20 ), 31.0 (C
11 ), 29.2 (C
15 ), 27.6 (C
22 ),
23.7 (C
30 ), 21.4 (C
16 ), 21.2 (C
27 ), 21.0 (C
34 ), 20.3 (C
2 ), 20.1 (C
32 ), 19.0
(C
6 ), 18.9 (C
26 ), 18.8 (C
24 ), 17.3 (C
25 ). IR (neat) 2928, 2863, 1770, 1743,
1465. HRMS (ESI-TOF) m/z: [M + Na]
+ Calcd for C 34 H 50 BrNNaO 6
+
670.2714; Found 670.2712.
3.2.10 12α-Bromo-23-hydroxy-3-oxo-olean-28,13β-olide
(8b)
O
H
H
H
Br
O
O
1
2
3
4
5
6
7
8
9
10
11
12 13
14
15
16
17
18
19
20
21
22
28
24
23
25
26
29
27
30
HO
A round bottom flask, equipped with magnetic stirring bar, was charged with
a solution of 7b (9.29 mmol, 6.026 g, 1 equiv) and K 2 CO 3 (9.29 mmol, 1.284 g,
1 equiv) in MeOH (93 ml). The flask was immersed into a preheated oilbath
(60 °C) and the reaction was left stirring at 60 °C for 1 h. After addition
of THF (93 ml) and a solution of copper sulfate pentahydrate (46.4 mmol,
11.597 g, 5 equiv) in H 2 O (93 ml), the resulting suspension was left stirring at
60 °C for 16 h. After cooling to room temperature, the mixture was extracted
with EtOAc (1 × 465 ml and 2 × 232 ml). The combined organic phases were
dried over MgSO 4 and concentrated under reduced pressure. Purification by
column chromatography (silica gel, heptane/EtOAc = 1:2) gave the target
53
1.95 (td, J = 13.5, 5.6 Hz, 1 H, H
15a ), 1.87–1.72 (m, 3 H, H
1a,9,11a ), 1.67–
1.62 (m, 2 H, H
22ab ), 1.56–1.49 (m, 3 H, H
5,6a,7a ), 1.46–1.42 (m, 4 H, H
6b,27 ),
1.40–1.32 (m, 3 H, H
1b,21ab ), 1.31–1.20 (m, 6 H, H
7b,15b,16b,26 ), 1.19 (s, 3 H,
H
24 ), 1.00 (s, 3 H, H
29 ), 0.94 (s, 3 H, H
25 ), 0.90 (s, 3 H, H
30 ).
13 C-NMR
(150 MHz, CDCl 3 , major): δ 178.9 (C
28 ), 171.1 (C
33 ), 170.4 (C
31 ), 169.7
(C
3 ), 91.6 (C
13 ), 68.4 (C
23 ), 56.3 (C
12 ), 52.5 (C
18 ), 48.3 (C
5 ), 45.6 (C
9 ), 44.9
(C
17 ), 44.1 (C
4 ), 43.6 (C
14 ), 42.3 (C
8 ), 40.1 (C
19 ), 37.3 (C
1 ), 36.2 (C
10 ), 34.0
(C
21 ), 33.8 (C
7 ), 33.4 (C
29 ), 32.0 (C
20 ), 31.0 (C
11 ), 29.2 (C
15 ), 27.6 (C
22 ),
23.7 (C
30 ), 21.4 (C
16 ), 21.2 (C
27 ), 21.0 (C
34 ), 20.3 (C
2 ), 20.1 (C
32 ), 19.0
(C
6 ), 18.9 (C
26 ), 18.8 (C
24 ), 17.3 (C
25 ). IR (neat) 2928, 2863, 1770, 1743,
1465. HRMS (ESI-TOF) m/z: [M + Na]
+ Calcd for C 34 H 50 BrNNaO 6
+
670.2714; Found 670.2712.
3.2.10 12α-Bromo-23-hydroxy-3-oxo-olean-28,13β-olide
(8b)
O
H
H
H
Br
O
O
1
2
3
4
5
6
7
8
9
10
11
12 13
14
15
16
17
18
19
20
21
22
28
24
23
25
26
29
27
30
HO
A round bottom flask, equipped with magnetic stirring bar, was charged with
a solution of 7b (9.29 mmol, 6.026 g, 1 equiv) and K 2 CO 3 (9.29 mmol, 1.284 g,
1 equiv) in MeOH (93 ml). The flask was immersed into a preheated oilbath
(60 °C) and the reaction was left stirring at 60 °C for 1 h. After addition
of THF (93 ml) and a solution of copper sulfate pentahydrate (46.4 mmol,
11.597 g, 5 equiv) in H 2 O (93 ml), the resulting suspension was left stirring at
60 °C for 16 h. After cooling to room temperature, the mixture was extracted
with EtOAc (1 × 465 ml and 2 × 232 ml). The combined organic phases were
dried over MgSO 4 and concentrated under reduced pressure. Purification by
column chromatography (silica gel, heptane/EtOAc = 1:2) gave the target