We report the first enantioselective total syntheses of the hasubanan alkaloid (−)-
metaphanine and the norhasubanan alkaloid (+)-stephadiamine. Key features of these
syntheses include diastereoselective oxidative phenolic coupling reaction and subsequent
regioselective intramolecular aza-Michael reaction, which efficiently construct the
hasubanan skeleton with the all-carbon quaternary stereogenic center at C13. Based on our
hypothesis regarding the biosynthetic pathway of (+)-stephadiamine, we found that (−) …

An asymmetric synthesis of (+)-stephadiamine has been accomplished featuring (a) an
enantioselective dearomatizative Michael addition to generate a quaternary stereocenter;(b)
a domino sequence involving reductive generation of nitrone from γ-nitro ketone followed by
a highly regio-and diastereo-selective intramolecular [3+ 2] cycloaddition to construct the
aza [4, 3, 3] propellane core with concurrent generation of two quaternary stereocenters and
two functional groups ready for subsequent transformations;(c) the Curtius rearrangement of …