SYNTHESIS IN THE SERIES OF ERYTHRINA ALKALOIDS: II. STERIC CONFIGURATION OF THE SYNTHETIC BASE

2-Cyclohexanone acetic acid ethyl ester oxime was hydrogenated in acidic medium to the corresponding amino ester, which is of the cis form, as by ring closure it gives a hexahydrooxindole which in turn is reduced by lithium aluminum hydride to cis-octahydroindole. Also, it has been shown that the amino ester can be transformed into cis-aminoethylcyclohexane. The high pressure Raney nickel hydrogenation of the oxime ester followed by lithium aluminum hydride reduction gave also cis-octahydroindole, although in neutral medium the trans form could have been expected.