OPP
H
H
HO
H 2 O
8
1,5-hydride shift
11/5-membered
ring system
5/8/5-membered
ring system
Fig. 68 Proposed
cyclization mechanism for
the formation of the 5/8/5membered ring system
OHC
HO
O
O
103
OHC
HO
O
104
O
O
105
OH
OHC
106
HO
O
6
6
6
6
Fig. 69 Structures of 103–
106
107
HO
HN
O
O
Fig. 70 Structure of
asperophiobolin A (107)
Sesterterpenoids
37