iboga from catharathine

stratosphere · Mon May 30, 2005 8:59 am

iboga and catharathine (periwinkle extract) are highly related structuraly which gives promise to the synthesis of iboga analogs from catharathine.

one possiblity is to carry out decarboxylation using the kochi reaction, followed by catalytic hydrogenation of the cyclohexene ring and simulatanous reduction of the halo bond created from the kochi reaction. the kochi reaction would seem a better choice then the hundiecker as its unclear what possible side reactions the presence of Br2 and of the COOBr intemediates might create.

http://scripts.iucr.org/cgi-bin/paper?dn1063&buy=1 indicates that heterogenous catalytic hydrogenation converts the cyclohexene ring to a cyclohexane.
of course the result of this would lack the 5 methoxy group that iboga has.