Epoxy Taxol

1
Epoxy Taxol

• Example of 2D-NMR

2
Basic structure
4 methyl singlets Position 20 oxetane
H9 and H10 2 Doublets deshielded
19
18
H5/H7 deshielded Coupled to same AB shielded H6
9
10
11
12
7
6
8
H13 dd desh. H14 ABX shielded
13
15
16/17
5
1
4
14
2
3
20
H2 (d) deshielded H3 (d) more shielded
3
1H NMR
d
o.m
Me (s)
t
d
dd
Ac
d
4
COSY
Gem- Me
3
5,7
9
6a,b
9
10
2
2
3
9
2H
10,
13
5
1H NMR
OH
10
20a
5
3
2
9
7
13
18
20b
6
1H NMR Expansion
4 Ac
18
20b
14b
6a
14a
6b
7
13C NMR
Ac
CC
CO
C-O
8
HMQC
9
HMQC
10
HMBC
12/11
8
8
1
15
CO Ac
15
1
OH
13
Me18
imp
11
(No Transcript)
12
(No Transcript)
13
NOESY
14
(No Transcript)
15
Conf. Of Ring B
16
Ring C
17
Ring C
18
Ring C Bottom
U-Shape
19
Ring A
20
Ring A
21
Long Range