ENANTIOSELECTIVE SYNTHESIS OF 3-AZABICYCLO[4.3.0]NONANE ALKALOIDS

The stereospecific synthesis of the monoterpene alkaloids (-)-alpha-skytanthine ((-)-2), (-)-N-demethyl-delta-sky-tanthine ((-)-7), and (+)-epidihydrotecomanine (+)-4 was achieved from a common intermediate 22, which in turn was obtained from (1R,4S,1'S)-2-(1'-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene (10), via a ketene aza-Claisen rearrangement. The piperidine derivative (+)-31, formally the aza-analogue of (+)-isoiridomyrmecin, was also obtained from the same intermediate 22.