Isocedranes

Cedranes are formally derived from farnesane by connection of bonds between C-1 and C-6, C-2 and C-11 as well as C-6 and C-10. Cedrane is formally converted into isocedrane by migration of the C-15 methyl group from C-3 to C-5. 

Isocedrane derivatives occur predominantly in Jungia species, exemplified by (+)-4-isocedren-15-al in Jungia malvaefolia and (+)-4-isocedren-15,14-olide and other isocedrenes in Jungia stuebelii. 

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