Enantioselective Synthesis of 3‐ Azabicyclo[4.3.0]nonane Alkaloids

The stereospecific synthesis of the monoterpene alkaloids (−)‐α‐skytanthine ((−)‐2), (−)‐N ‐demethyle‐δ‐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.