One possible mechanism for the formation of the 6/5/4-membered ring system
starting from geranylfarnesyl diphosphate (8) is shown in Fig. 84 [3]. In this
proposal, the cyclization reactions occur twice to generate the characteristic 6/5/4O
O
O
118
Fig. 83 Structure of lintenone (118)
OPP
OPP
H
OPP
O
H
+
HO
H
HO
H
O
OPP
H
+
8
118
formation of epoxide
Fig. 84 Proposed cyclization mechanism for the formation of the 6/5/4-membered ring system of 118
44
T. Mitsuhashi and I. Abe